Nature, 1984 Jul 5-11, 310(5972), 25 - 31 Sequence of a Drosophila segmentation gene: protein structure homology with DNA-binding proteins; Laughon A et al.; Mutations in the fushi tarazu (ftz) locus of Drosophila result in embryos with half the usual number of body segments . The sequences of the wild-type gene, a temperature-sensitive allele and a dominant mutant allele are presented . A portion of the conserved protein domain present in ftz and several homoeotic genes resembles the DNA-binding region of prokaryotic DNA-binding proteins, and is also similar to products of the yeast mating-type locus. Science, 1984 Jun 22, 224(4655), 1312 - 6 The interleukin-2 T-cell system: a new cell growth model; Cantrell DA et al.; Synchronized interleukin-2 receptor-positive T cells, homogeneous immunoaffinity-purified interleukin-2, and a monoclonal antibody to interleukin-2 receptors were used to show that only three factors are critical for T-cell cycle progression: interleukin-2 concentration, interleukin-2 receptor density, and the duration of the interleukin-2 receptor interaction . Since the proliferative characteristics of T cells are identical to those of both prokaryotic and all other eukaryotic cells, these findings provide a new model that accounts fully for the variables that determine cell cycle progression. Nature, 1984 Jun 14-20, 309(5969), 637 - 9 Xenopus oocytes can secrete bacterial beta-lactamase; Wiedmann M et al.; Most secretory proteins are synthesized as precursor polypeptides carrying N-terminal, hydrophobic sequences which, by means of a signal recognition particle (SRP), trigger the membrane transfer of the polypeptide and are subsequently cleaved off . The signal sequences appear to be interchangeable between prokaryotes and eukaryotes . In bacteria, secretion only involves the crossing of a membrane, whereas in eukaryotes the secretory process can be separated into two distinct phases: translocation across the membrane of the rough endoplasmic reticulum and subsequent intraluminal transport by processes involving vesicle budding and fusion . Since secretory proteins must be distinguished from other soluble proteins destined for various sites in the reticular system, it is conceivable that eukaryotic secretory proteins possess additional markers distinct from the signal peptide to guide the polypeptide after its transfer through the membrane . Proteins are secreted at different rates from a eukaryotic cell, suggesting a role in intracellular transport for receptors with differing affinities for some topogenic features in secretory proteins . We have tested this possibility by introducing into the lumen of eukaryotic rough endoplasmic reticulum a prokaryotic protein which, by virtue of its origin, had not been adapted to the eukaryotic secretory pathway . We reasoned that secretion of the bacterial protein would indicate that after membrane transfer no topogenic signal(s) and corresponding recognition system(s) are required . We report here that this is indeed the case. Biochemistry, 1984 Jun 5, 23(12), 2691 - 5 Chemical synthesis and 2H NMR investigations of polyisoprenols: dynamics in model membranes; de Ropp JS et al.; Polyisoprenols (PIs) such as dolichol and undecaprenol have been shown to play an important role as enzymatic cofactors in the synthesis of glycoconjugates of both prokaryotic and eukaryotic cells . Presented here is a synthetic route used for obtaining specifically labeled {omega,omega-(C2H3)2}PIs that initiates with the selective oxidation of the omega-terminal double bond of the PI with N-bromosuccinimide . Continuation of the reaction sequence produces an omega-terminal aldehyde three carbons shorter than the original PI . A Wittig reaction with an appropriate deuterium-labeled phosphonium salt is then used to form an omega-terminal-deuterated PI identical with the starting material except for replacement of 1H with 2H at the two omega-terminal methyls of the PI . Deuterium NMR spectra of {omega, omega-(C2H3)2}geraniol and -farnesol incorporated into phospholipid multilamellar vesicles show powder patterns . The quadrupole splitting of the 2H NMR signals was interpretable in terms of the degree of orderedness of the 2H-labeled site . The pure trans isomer geraniol gave rise to a single set of splittings for each C2H3 group while farnesol, a mixture of isomers, showed multiple quadrupole splittings . The quadrupole splittings of the PIs increased with increasing concentration of label and with lowering of temperature . Deuterium NMR T1 measurements, revealing rates of motion of the 2H-labeled site, showed fast motion for {omega,omega-(C2H3)3}geraniol relative to {omega,omega-(C2H3)2}cholesterol under similar conditions . A correlation time of 5 X 10(-10) s was estimated for {omega,omega-(C2H3)2}geraniol, which was 1 order of magnitude faster than for {26,27-(C2H3)2}cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS) Can J Biochem Cell Biol, 1984 Jun, 62(6), 311 - 20 The ribosomal 5.8S RNA: eukaryotic adaptation or processing variant? Nazar RN. A striking difference between the cytoplasmic ribosomes of eukaryotes and prokaryotes is the presence (in eukaryotes) of one additional RNA component, the 5.8S rRNA . This RNA, which is hydrogen bonded to the cognate high molecular weight RNA of the large subunit, is about 160 nucleotides in length, and is cotranscribed with the high molecular weight rRNA as part of a much larger precursor molecule, the nucleolar 36S-45S rRNA . Because of its relatively small size the 5.8S RNA is considered a good model for studies on rRNA structure, synthesis, maturation, ribosomal integration, function, and even evolution . Over the last decade numerous studies have examined these questions with many interesting results, including the probability that this RNA sequence may actually be present in all ribosomes, although not necessarily as a separate RNA component . Their findings are summarized in this review. J Anim Sci, 1984 Jun, 58(6), 1465 - 83 Ionophores: their effect on production efficiency and mode of action; Bergen WG et al.; Carboxylic polyether ionophores, when fed to growing ruminants improve efficiency of production . This review summarizes the observed effects of ionophores on the ruminal fermentation and the host animal . The effect of ionophores on prokaryotic and eukaryotic cells is described and this knowledge is then utilized to explain many of the observed ionophore effects on the rumen fermentations and host gastrointestinal physiology. Proc Natl Acad Sci U S A, 1984 Jun, 81(12), 3665 - 9 Correlation of lac operator DNA imino proton exchange kinetics with its function; Cheung S et al.; The kinetics for imino hydrogen exchange, at individual base pairs in the DNA sequence corresponding to the lactose operon operator of Escherichia coli, has been examined by NMR saturation recovery measurements as a function of temperature . Three 17-base-pair subsections of the lac operator DNA were chemically synthesized for these studies . The results support our previous observations in the 36-base-pair complete lac operator DNA fragment that has been used in our previous NMR studies . The results indicate faster opening kinetics at a GTG/CAC that is also the site of operator mutations leading to the highest level of constitutive beta-galactosidase synthesis . The GTG/CAC sequence occurs frequently and often symmetrically in prokaryotic and eukaryotic DNA sites where one anticipates specific protein interaction for gene regulation or recombination. Nucleic Acids Res, 1984 May 25, 12(10), 4411 - 27 A computer algorithm for testing potential prokaryotic terminators; Brendel V et al.; The nucleotide sequences of 30 factor-independent terminators of transcription with RNA polymerase from E . coli have been compiled and analyzed . The standard features - a stretch of thymine residues and a preceding dyad symmetry - are shared by most sequences, but there are striking exceptions which indicate that these features alone are not sufficient to describe these sites . In two thirds of the sequences the 3'-half of the dyad symmetry contains the pentanucleotide CGGG (G/C) or a close derivative; about one third have TCTG or a close derivative just downstream of the termination point . The TCTG -box might be implied in termination of stringently controlled operons of E . coli . An algorithm to locate terminators in templates of known nucleotide sequence has been constructed on the basis of correlation to the distribution of dinucleotides along the aligned signal sequences . The algorithm has been tested on natural sequences of a total length of about 11,500 N . It finds all known independent terminators and only a few other sites, including some of the rho-dependent and putative terminators. Nucleic Acids Res, 1984 May 25, 12(10), 4259 - 79 Secondary structure of mouse 28S rRNA and general model for the folding of the large rRNA in eukaryotes; Michot B et al.; We present a secondary structure model for the entire sequence of mouse 28S rRNA (1) which is based on an extensive comparative analysis of the available eukaryotic sequences, i.e . yeast (2, 3), Physarum polycephalum (4), Xenopus laevis (5) and rat (6) . It has been derived with close reference to the models previously proposed for yeast 26S rRNA (2) and for prokaryotic 23S rRNA (7-9) . Examination of the recently published eukaryotic sequences confirms that all pro- and eukaryotic large rRNAs share a largely conserved secondary structure core, as already apparent from the previous analysis of yeast 26S rRNA (2) . These new comparative data confirm most features of the yeast model (2) . They also provide the basis for a few modifications and for new proposals which extend the boundaries of the common structural core (now representing about 85% of E . coli 23S rRNA length) and bring new insights for tracing the structural evolution, in higher eukaryotes, of the domains which have no prokaryotic equivalent and are inserted at specific locations within the common structural core of the large subunit rRNA. Nature, 1984 May 31-Jun 6, 309(5967), 467 - 9 Evolution of phosphofructokinase--gene duplication and creation of new effector sites; Poorman RA et al.; Phosphofructokinases (PFK; EC 2.7.1.11) are tetrameric enzymes that have a key role in the regulation of glycolysis; as such, they are subject to allosteric activation and inhibition by various metabolites . Eukaryotic PFKs are about twice the size of prokaryotic enzymes and are regulated by a wider repertoire of effectors: for example, the subunit molecular weights of rabbit muscle (RM) PFK and Bacillus stearothermophilus (Bs) PFK are 82,000 and 36,000, respectively . Both enzymes are activated by ADP (or AMP), but RM-PFK is also activated by fructose bisphosphates (FBP) and inhibited by ATP and citrate . This, together with other evidence, has led to speculation that mammalian PFKs have evolved by duplication of a prokaryotic gene, although previous peptide analysis failed to reveal internal homology in RM-PFK . Here we demonstrate clear homology among the N- and C-halves of RM-PFK and Bs-PFK, thus establishing an evolutionary relationship by series gene duplication and divergence . Furthermore, detailed knowledge of the Bs-PFK structure provides the basis for inferences concerning the structural organization of RM-PFK and the evolution of new effector sites in the enzyme tetramer. Hoppe Seylers Z Physiol Chem, 1984 May, 365(5), 577 - 85 Purification and properties of a manganese-containing superoxide dismutase from Acholeplasma laidlawii; Reinards R et al.; From the prokaryotic microorganism Acholeplasma laidlawii the major manganese-containing superoxide dismutase has been purified to homogeneity, as judged by polyacrylamide gel electrophoresis . The molecular mass of the enzyme was found to be 41 500 Da . It consists of two subunits of identical size and has an isoelectric point of 6.4 . The enzyme contains 0.51 +/- 0.05 atoms of manganese per subunit . Its amino-acid composition and light absorption spectra are presented and compared with Mn- and Fe- containing superoxide dismutases from other prokaryotic organisms. Proc Natl Acad Sci U S A, 1984 May, 81(10), 3153 - 7 Homologous recombination between plasmids in mammalian cells can be enhanced by treatment of input DNA; Kucherlapati RS et al.; We have used the eukaryotic-prokaryotic shuttle vector pSV2Neo to demonstrate that cultured mammalian somatic cells have the enzymatic machinery to mediate homologous recombination and that the frequency of this recombination can be enhanced by pretreatment of the input DNA . Two nonoverlapping deletion mutants of pSV2Neo were constructed, each affecting the bacterial aminoglycoside 3'-phosphorylase gene (the neo gene), which confers resistance to aminoglycoside antibiotics on bacteria and resistance to the antibiotic G418 on mammalian cells . Mammalian cells transfected with either deletion plasmid alone yield no G418 -resistant colonies . Cells cotransfected with both deletion plasmids yield G418 -resistant colonies with high frequency . We show that these resistant colonies result from recombination involving homologous crossing-over or gene conversion between the deletion plasmids by rescuing from the resistant cells both types of reciprocal recombinant, full-length plasmids, and doubly deleted plasmids . Cutting one of the input plasmids to generate a double-stranded gap in the neo gene considerably enhances the frequency of homologous recombination within the gene . This suggests that targeting exogenous DNA to specific sites in mammalian chromosomes could be facilitated by suitable pretreatment of the DNA. Proc Natl Acad Sci U S A, 1984 May, 81(10), 2950 - 4 DNA methylation of three 5' C-C-G-G 3' sites in the promoter and 5' region inactivate the E2a gene of adenovirus type 2; Langner KD et al.; The E2a gene of human adenovirus type 2 (Ad2) encodes the 72-kilodalton DNA-binding protein . We previously described perfect inverse correlations between the methylation of all 5' C-C-G-G 3' sequences in the Ad2 E2a gene in virus-transformed hamster cells containing viral DNA sequences in an integrated state and the extent to which this gene is expressed . We subsequently showed that in vitro methylation of all 14 5' C-C-G-G 3' sequences in the cloned E2a gene by prokaryotic Hpa II DNA methyltransferase leads to transcriptional inactivation after microinjection into Xenopus laevis oocytes . The unmethylated cloned E2a gene is expressed in these cells . We report here the construction of partly methylated clones of the E2a gene . In the promoter (5')-methylated construct, three 5' C-C-G-G 3' sequences at the 5' end of the subclone were methylated . One of these sites is located 215 base pairs (bp) upstream (bp 26,169 of Ad2 DNA), and two sites are located 5 and 23 bp downstream from the cap site (bp 25,931 and 25,949 of Ad2 DNA) of the E2a gene . This construct was transcriptionally inactive upon microinjection into nuclei of X . laevis oocytes . In the gene (3')-methylated construct, 11 5' C-C-G-G 3' sequences in the main part of the transcribed gene region were methylated in vitro . This construct was transcribed in X . laevis oocytes, and at least some of the Ad2-specific RNA synthesized was initiated at the same sites as in Ad2-infected human KB cells . Both mock-methylated constructs were transcribed into Ad2-specific RNA in X . laevis oocytes . These results demonstrate that DNA methylations at or close to the promoter and 5' end of the E2a gene cause transcriptional inactivation . Perhaps only one methyl group would be adequate for inactivation; in vivo methylation of more than one cytosine may be a form of safeguard or redundancy. EMBO J, 1984 May, 3(5), 1109 - 13 The primary structure of elongation factor EF-1 alpha from the brine shrimp Artemia; van Hemert FJ et al.; cDNA as well as amino acid sequencing has revealed the complete primary structure of elongation factor EF-1 alpha from the brine shrimp Artemia . A comparison with the published sequences of bacterial EF-Tu, mitochondrial EF-Tu and chloroplastic EF-Tu shows that distinct areas of these polypeptide chains are conserved in evolution . The evolutionary distance between prokaryotic and eukaryotic types of EF-Tu is larger than among bacterial and organellar EF- Tus . A number of regions present in both EF-Tu and EF-G from Escherichia coli are also found in EF-1 alpha from Artemia. Biochem Biophys Res Commun, 1984 Apr 30, 120(2), 607 - 13 Enzymatic synthesis of the penicillin and cephalosporin nuclei from an acyclic peptide containing carboxymethylcysteine; Bowers RJ et al.; The tripeptide delta-(L- carboxymethylcysteinyl )-L-cysteinyl-D-valine (L-CMC-CV) is converted sequentially into the CMC analog of isopenicillin N, the CMC analog of penicillin N, and the CMC analog of desacetoxycephalosporin C by, respectively, isopenicillin N synthetase, isopenicillin N epimerase, and desacetoxycephalosporin C synthetase, all isolated from the beta-lactam producing prokaryote Streptomyces clavuligerus. Nature, 1984 Apr 26-May 2, 308(5962), 863 - 4 Signal sequence mutations disrupt feedback between secretion of an exported protein and its synthesis in E . coli; Kumamoto CA et al.; Recent studies in a eukaryotic system indicate that a block in secretion can lead to a block in the translation of secretory proteins . This feedback on protein synthesis is thought to be a result of an interaction of the signal recognition particle with the signal sequences of nascent proteins . Genetic studies in the prokaryote Escherichia coli suggest that a complex secretion machinery and a similar feedback mechanism exist . In addition, mutations affecting two genes, secA and secC, thought to encode components of the bacterial secretion machinery, selectively interfere with the synthesis of exported proteins . This selective interference with translation may be a result of recognition by the secretion machinery of signal sequences . If so, alteration of the signal sequence of a particular protein by mutation should eliminate the block in synthesis for that protein . We show here that signal sequence mutants for an exported protein, maltose binding protein, prevent the block in synthesis of this protein in a secA mutant. Proc Natl Acad Sci U S A, 1984 Apr, 81(8), 2322 - 6 Immunological evidence for the in vivo occurrence of (2'-5')adenylyladenosine oligonucleotides in eukaryotes and prokaryotes; Laurence L et al.; A monoclonal antibody highly specific for (2'-5')adenylyladenosine oligonucleotides was used together with a 125I-labeled analog of this compound to detect and quantify phosphorylated and nonphosphorylated (2'-5')adenylyladenosine oligonucleotides in a variety of tissues and cells . These oligonucleotides were first assayed as a whole in perchloric acid extracts and then further individually characterized by HPLC analysis . Their sensitivity to alkaline phosphatase, snake venom phosphodiesterase, and T2 RNase was systematically checked . Nonphosphorylated (2'-5')adenylyladenosine oligonucleotides were found in mammalian tissues as well as in yeast and bacteria . In normal mouse brain, lung, heart, pancreas, spleen, kidney, and liver their concentrations ranged from 10 to 200 pmol/g wet weight, depending on tissue and strain . The oligonucleotides were mainly dimers, trimers, tetramers, and pentamers . In addition, phosphorylated (2'-5')adenylyladenosine oligonucleotides were shown in liver and kidney extracts. Virologie, 1984 Apr-Jun, 35(2), 119 - 25 Effect of biologically active compounds (anthracyclines and ethidium bromide) on some membrane-mediated processes in the course of viral infection . Investigations on a prokaryotic (bacteriophage-bacterium) system; Mihalache O et al.; Anthracycline antibiotics--violamycin B1 and adriamycin--have an obvious effect on the efficiency of phage lambda L47.1 DNA transfection into E . coli Q358 cells . Treatment with anthracyclines of either phage DNA or bacterial cells results in a marked decrease in the number of transfectants per microgram DNA . On the other hand, adsorption of phage lambda gt WES to E . coli LE392 is considerably modified by exposure to anthracyclines of either the phage or the host cells. Proc Natl Acad Sci U S A, 1984 Apr, 81(7), 1971 - 5 Use of prokaryotic-derived probes to identify poly(sialic acid) in neonatal neuronal membranes; Vimr ER et al.; Three prokaryotic-derived probes to identify and study the temporal expression of polysialosyl units in neuronal tissue have been developed . A polyclonal antibody, a bacteriophage-derived endo-neuraminidase, and an Escherichia coli K1 sialyltransferase are all specific for either recognizing or synthesizing poly(sialic acid) containing alpha-2,8-ketosidic linkages . Polysialosyl immunoreactivity with apparent Mr values of 180,000-240,000 was specific for developing neuronal tissue; it was not detected in neonatal liver or kidney or in adult brain tissue . The developmentally regulated disappearance in poly(sialic acid) is consistent with the probes described here recognizing the polysialosyl carbohydrate units of a neuronal cell adhesion molecule (N-CAM) . Treatment of brain extracts with a bacteriophage-derived endo-neuraminidase specific for alpha-2,8-linked polysialosyl units abolished the immunoreactivity . The material solubilized by endo-neuraminidase was isolated, reduced with borotritide, and shown to contain oligomers of sialic acid with three to six sialyl units . Treatment of the 3H-labeled oligosialic acid with exo-neuraminidase quantitatively converted the radioactivity to sialitol, establishing that the brain-derived oligomers were composed solely of sialic acid . A membranous sialytransferase from E . coli K1 that can transfer sialic acid to exogenous acceptors of oligo- or poly(sialic acid) also recognized rat brain membranes, further substantiating the presence of poly(sialic acid) in rat brain . This conclusion was confirmed by using a mutant of E . coli K1 that was defective in the synthesis of poly(sialic acid) and could only transfer sialic acid to exogenous acceptors of oligo- or poly(sialic acid) . Sialyl polymer synthesis was restored in the mutant when brain membranes were added as exogenous acceptor. Mol Cell Biochem, 1984 Apr, 62(1), 13 - 24 Structural and functional properties of DNA polymerase delta from rabbit bone marrow; Byrnes JJ; DNA polymerase delta, the most recently described class of eukaryotic DNA polymerase, has been purified to apparent homogeneity from rabbit bone marrow . Unlike the previously known eukaryotic DNA polymerases, delta has a 3' to 5' exonuclease as an integral component of its 122 000 molecular weight, single polypeptide structure . Similar to the function with prokaryotic DNA polymerases, the 3' to 5' exonuclease assists DNA polymerase delta in maintaining the fidelity of DNA synthesis by excising misincorporated nucleotides . DNA polymerase delta and the longer known eukaryotic DNA polymerase alpha are similar in many features . Both are very sensitive to sulfhydryl inhibitors such as N-ethylmaliemide (NEM) and to the antibiotic aphidicolin . Such criteria distinguish alpha and delta from DNA polymerases beta and gamma . This has led to the conclusion that nuclear DNA replication, which is sensitive to NEM and aphidicolin, is carried out by DNA polymerase alpha . However, the similar sensitivity of delta to these reagents requires that the role of alpha and delta in nuclear DNA replication be further defined . In many features DNA polymerase delta is also similar to the viral induced DNA polymerases such as the Herpes simplex virus DNA polymerases which also have associated 3' to 5' exonuclease . Understanding of DNA synthesis and the mechanism of DNA replication fidelity in mammalian cells depends upon a further understanding of both DNA polymerases alpha and delta and the nature of the relationship they have to each other. Proc Natl Acad Sci U S A, 1984 Apr, 81(8), 2290 - 4 High-level expression of a chemically synthesized gene for human interferon-gamma using a prokaryotic expression vector; Jay E et al.; A chemically synthesized gene for human interferon-gamma has been cloned into a prokaryotic expression vector under the regulation of a synthetic constitutive transcriptional-translational control unit that contains a strong bacteriophage T5 early promoter and a strong ribosome-binding site . Cells harboring the recombinant plasmid express high levels (4 X 10(9) units per liter of culture) of antiviral activity specific for interferon-gamma . Analysis of total cell lysates on NaDodSO4/polyacrylamide gels revealed a 17,200-dalton protein, expected for the nonglycosylated form of human interferon-gamma, that constitutes greater than 15% of total cell protein. Nucleic Acids Res, 1984 Mar 26, 12(6), 2649 - 67 Xenopus laevis 18S ribosomal RNA: experimental determination of secondary structural elements, and locations of methyl groups in the secondary structure model; Atmadja J et al.; 18S ribosomal RNA from X . laevis was subjected to partial digestion with ribonucleases A or T1 under a variety of conditions, and base-paired fragments were isolated . Sequence analysis of the fragments enabled five base-paired secondary structural elements of the 18S RNA to be established . Four of these elements (covering bases 221-256, 713-757, 1494-1555 and 1669-1779) confirm our previous secondary structure predictions, whereas the fifth (comprising bases 1103-1125) represents a phylogenetically conserved "switch" structure, which can also form in prokaryotic 16S RNA . The results are incorporated into a refined model of the 18S RNA secondary structure, which also includes the locations of the many methyl groups in X . laevis 18S RNA . In general the methyl groups occur in non-helical regions, at hairpin loop ends, or at helix boundaries and imperfections . One large cluster of 2'-O-methyl groups occurs in a region of complicated secondary structure in the 5'-one third of the molecule. Nucleic Acids Res, 1984 Mar 26, 12(6), 2837 - 50 Nucleotide sequence of the gene for the P680 chlorophyll alpha apoprotein of the photosystem II reaction center from spinach; Morris J et al.; The DNA sequence of 2210 nucleotides including the gene for the "51 kd" chlorophyll alpha-conjugated thylakoid membrane protein associated with the photosystem II reaction center of spinach has been determined . This protein is functionally identical with the P680 chlorophyll alpha apoprotein that catalyses the primary light-induced photochemical processes of photosystem II (Camm, E.L . and Green, B.R . (1983) Biochim . Biophys . Acta 724 291-293) . The only large open reading frame in the sequence consists of 508 triplets encoding a protein of molecular mass of 56,246 kd . The deduced amino acid sequence shows clustering of hydrophobic residues into seven core regions which probably traverse the membrane, and a large hydrophilic domain of about 200 amino acids interspersed between span VI and VII . Potential transcription promotor and terminator signals flanking the structural gene show prokaryotic-like features . Seven discrete RNA species ranging in size from 2.0 to over 5.0 kilobases display complementarity to apoprotein coding sequences implying that the region can be polycistronically transcribed . The primary transcript includes information for at least two further genes coding for subunits of the cytochrome b/f complex. Eur J Biochem, 1984 Mar 15, 139(3), 451 - 7 The 5S RNA binding protein from yeast (Saccharomyces cerevisiae) ribosomes . An RNA binding sequence in the carboxyl-terminal region; Yaguchi M et al.; The carboxyl-terminal half (CN2 fragment) of the yeast 5S RNA binding protein (YL3) retains an ability to form homogeneous ribonucleoprotein complexes with RNA although the N-terminal half (CN1) appears to confer specificity for the 5S RNA molecule {Nazar, R.N., Yaguchi, M., Willick, G.E., Rollin, C.F . and Roy, C . (1979) Eur . J . Biochem . 102, 573-582} . The nucleic acid binding site in this fragment was more clearly delineated by cleaving the CN2 fragment with a variety of enzymatic and chemical reagents and further examining the ability of the products to form RNA-peptide complexes . Hot acetic acid treatment produced a 47-residue subfragment (CN2-A1) which originated from the C terminus and continued to form stable ribonucleopeptide complexes . The amino acid sequence of this subfragment was determined to be: -Pro-Ala-Phe-Lys-Pro-Thr-Glu-Lys50-Phe-Thr-Lys-Glu-Gln-Tyr-Ala-Ala -Glu60-Ser-Ly s -Lys-Tyr-Arg-Gln-Thr-Lys-Leu-Ser70-Lys-Gln-Gln-Arg-Ala-Ala-Arg-Val -Ala-Ala80-Ly s -Ile-Ala-Ala-Leu-Ala-Gly-Gln-Gln-COOH, with 12 of the 16 basic residues in the CN2 fragment being present in this binding site . The amino acid sequence of the CN2-A1 fragment bears a limited homology in both amino acid and charge distribution with histone 2B from mammals and with one of the 5S RNA binding proteins (EL25) from Escherichia coli . The results suggest that many protein binding sites for nucleic acids may share common structural features and further support the notion that the single large eukaryotic 5S RNA protein may have evolved through a fusion of genes for the multiple 5S RNA binding proteins in prokaryotes. Biochem Biophys Res Commun, 1984 Mar 15, 119(2), 657 - 62 Synthesis of rat apolipoprotein E by Escherichia coli infected with recombinant bacteriophage; de Jong FA et al.; A cDNA library was constructed from rat liver polyadenylated RNA using the expression vector lambda gt11-Amp3 . Several clones expressing antigenic determinants for rat apolipoprotein E were identified . The cDNA insert in one clone was further characterized and found to have a sufficient length (1120 base pairs) to code for full length apolipoprotein E . Restriction mapping and nucleotide sequencing showed the clone to contain the coding region for apolipoprotein E flanked by about 120 nucleotides at the 3'-side and by about 64 nucleotides on the 5'-side . One of the proteins produced by the clone was found to be a prokaryotic/eukaryotic hybrid protein reacting with antibodies to both bacterial beta-galactosidase and rat apolipoprotein E. Biochim Biophys Acta, 1984 Mar 14, 770(2), 127 - 35 Sodium-dependent uptake of taurine in encapsulated Staphylococcus aureus strain M; Bieber EJ et al.; A novel uptake system for the unusual sulfonated amino acid taurine was discovered in the prokaryote, encapsulated Staphylococcus aureus strain M . This strain has been shown previously to contain taurine in its capsular polysaccharide . Taurine uptake by whole cells incubated in buffer showed a saturable dependency upon Na+ and taurine uptake was itself a saturable process, stimulated by glucose, and markedly affected by temperature . No evidence was found for the inducibility of taurine uptake . In the presence of 10 mM NaCl Lineweaver-Burk plots revealed a Km of 42 microM and Vmax of 4.6 nmol/min per mg dry weight for taurine uptake at 37 degrees C . Increasing concentrations of Na+ decreased the Km of the system and appeared to increase the Vmax . Of various other cations tested only Li+ supported marked taurine uptake . Excess unlabelled taurine did not cause efflux of radioactivity taken up . Taurine was taken up into cold trichloroacetic acid-soluble material and did not chromatograph as taurine, indicating rapid metabolism during or closely following uptake . Taurine uptake appeared to occur via a highly specific system because amino acids representing the major known groups of amino acid transport systems in S . aureus did not inhibit taurine uptake, and uptake was only slightly diminished by the structurally closely related compounds hypotaurine and 3-amino-1-propane sulfonic acid . Sulfhydryl group reagents, electron transport inhibitors, an uncoupler and inhibitors of Na+-linked transport processes inhibited taurine uptake . A variety of other metabolic inhibitors had little effect on taurine uptake. Orig Life, 1984 Mar, 13(3-4), 183 - 93 From proto-mitosis to mitosis--an alternative hypothesis on the origin and evolution of the mitotic spindle; Roos UP; Based on the assumption that the ancestral proto-eukaryote evolved from an ameboid prokaryote I propose the hypothesis that nuclear division of the proto-eukaryote was effected by the same system of contractile filaments it used for ameboid movement and cytosis . When the nuclear membranes evolved from the cell membrane, contractile filaments remained associated with them . The attachment site of the genome in the nuclear envelope was linked to the cell membrane by specialized contractile filaments . During protomitosis , i.e., nuclear and cell division of the proto-eukaryote, these filaments performed segregation of the chromosomes, whereas others constricted and cleaved the nucleus and the mother cell . When microtubules (MTs) had evolved in the cytoplasm, they also became engaged in nuclear division . Initially, an extranuclear bundle of MTs assisted chromosome segregation by establishing a defined axis . The evoluntionary tendency then was towards an increasingly important role for MTs . Spindle pole bodies ( SPBs ) developed from the chromosomal attachment sites in the nuclear envelope and organized an extranuclear central spindle . The chromosomes remained attached to the SPBs during nuclear division . In a subsequent step the spindle became permanently lodged inside the nucleus . Chromosomes detached from the SPBs and acquired kinetochores and kinetochore-MTs . At first, this spindle segregated chromosomes by elongation, the kinetochore-MTs playing the role of static anchors . Later, spindle elongation was supplemented by poleward movement of the chromosomes . When dissolution of the nuclear envelope at the beginning of mitosis became a permanent feature, the open spindle of higher eukaryotes was born. J Biol Chem, 1984 Feb 25, 259(4), 2311 - 20 In vivo studies of pyridine nucleotide metabolism in Escherichia coli and Saccharomyces cerevisiae by carbon-13 NMR spectroscopy; Unkefer CJ et al.; Pyridine nucleotide metabolism has been studied in vivo in a prokaryotic (Escherichia coli) and a eukaryotic (Saccharomyces cerevisiae) system cultured in a medium containing carbon-13-labeled nicotinic acid, followed by NMR detection of the labeled organisms . Chemical exchange between oxidized and reduced nucleotides is found to be sufficiently slow on the NMR time scale to permit the observation of separate resonances corresponding to each redox state . The possibility of significant exchange broadening of reduced pyridine nucleotide resonances under some conditions was further evaluated based on comparative NMR studies utilizing organisms cultured in the presence of either {2-13C}nicotinate or {5-13C}nicotinate . Based on these experiments, it was concluded that broadening as a consequence of intermediate exchange is not significant . Although it was initially anticipated that the carbon-13 resonances arising from the di- and triphosphopyridine nucleotide pools could not be distinguished, the absence of observable resonances corresponding to reduced nucleotides in oxygenated yeast and E . coli cells suggests that the NMR method is fairly specific for determining the redox status of the diphosphopyridine nucleotide pool . Studies of the effects of a variety of perturbations including variation of the oxygen supply, addition of ethanol, and addition of the oxidative phosphorylation uncoupler dinitrophenol have been carried out . Dramatic differences in the response of the catabolic reduction charge, CRC = {NADH}/{NADH} + {NAD+}, between the yeast and E . coli cells are observed . The CRC values for the yeast undergo large changes in response to these perturbations which are not observed for the bacterial cells. Nucleic Acids Res, 1984 Feb 10, 12(3), 1749 - 63 Doublet frequencies in evolutionary distinct groups; Nussinov R; We analyze the dinucleotide frequencies of occurrence and preferences separately within the vertebrates, nonvertebrates, DNA viruses, mitochondria, RNA viruses, bacteria and phage sequences . Over half a million nucleotides from more than 400 sequences were used in this study . Distinct patterns are observed . Some of the patterns are common to all sequences, some to either eukaryotes or prokaryotes and others to the subgroups within them . Doublets are the most basic ingredient of order in nucleotide sequences . We suggest that their preferences and the arrangement of nucleotides in the DNA in general is determined to a large extent by the conformational and packaging considerations of the double helix . Some principles of DNA conformation are viewed in light of our results. Nucleic Acids Res, 1984 Feb 10, 12(3), 1707 - 24 The intron boundaries and flanking rRNA coding sequences of Calliphora erythrocephala rDNA; Smith VL et al.; We have sequenced the available cloned examples of the intron-coding sequence junctions for the rDNA of the higher Dipteran, Calliphora erythrocephala . The introns interrupt the rDNA at the same position as the type 1 intron family detected in Drosophila melanogaster and D . virilis (10,11) . A duplication of 14 base pairs of the 28S rRNA coding sequence surrounds a short version of the major genomic length class of introns . This same duplication is associated with boundaries of the type 1 introns in D . virilis and D . melanogaster (10, 13,14) . We have detected considerable homology between the 3' intron sequences of C . erythrocephala and D . virilis . The rRNA coding sequences flanking the introns are extremely homologous in C . erythrocephala, D . melanogaster and D . virilis, with only one small region of significant divergence . This corresponds to a variable stem region previously identified in eukaryotic 28S rRNA at a site analogous to the L1 ribosomal protein binding site of prokaryotic 23S rRNA (27). Arch Biochem Biophys, 1984 Feb 1, 228(2), 617 - 20 Enzymatic defenses against oxygen toxicity in the hydrothermal vent animals Riftia pachyptila and Calyptogena magnifica; Blum J et al.; Two deep-sea hydrothermal vent organisms, the tube worm Riftia pachyptila and the clam Calyptogena magnifica, contain superoxide dismutase, dianisidine peroxidase, and glutathione peroxidase . The tube worm trophosome exhibits an iron-containing superoxide dismutase, ordinarily associated with prokaryotes and not previously seen in an animal tissue, in accord with the presence of symbiotic bacteria in this tissue . The enzymes which provide a defense against oxygen toxicity are thus present in these animals. Gene, 1984 Feb, 27(2), 223 - 32 New cosmid vectors developed for eukaryotic DNA cloning; Brady G et al.; A series of ColE1 and pSC101 cosmid vectors have been constructed suitable for cloning large stretches of DNA . All contain a single BamHI site allowing cloning of Sau3A, MboI, BglII, BclI , and BamHI-generated fragments . These vectors have the following characteristics: (i) they are relatively small (1.7-3.4 kb); (ii) the BamHI cloning site is flanked by restriction enzyme sites enabling direct cloning of unfractionated insert DNA without generating multiple insert or vector ligation products { Ish - Horowitz and Burke, Nucl . Acids Res . 9 (1981) 2989-2998}; (iii) two vectors ( pHSG272 and pHSG274 ) contain a hybrid Tn5 KmR/ G418R gene which is selectable in both prokaryotic and eukaryotic cells, making them suitable for transferring DNA into eukaryotic cells, and (iv) the different prokaryotic selectable markers available in the other vectors described facilitate cosmid rescue of the transferred DNA sequences from the eukaryotic cell: CmR, ApR, KmR, ( pHSG429 ), CmR, ( pHSG439 ), colicin E1 immunity ( pHSG250 ), (v) the cosmid pHSG272 was used successfully to construct a shuttle vector based on the BPVI replicon { Matthias et al., EMBO J . 2 (1983) 1487-1492}. Gene, 1984 Feb, 27(2), 131 - 49 The use of transposon Tn5 mutagenesis in the rapid generation of correlated physical and genetic maps of DNA segments cloned into multicopy plasmids--a review; de Bruijn FJ et al.; The properties of transposon Tn5 that render it useful for in vivo mutagenesis of cloned DNA sequences are reviewed . Transposition frequency, insertional specificity, polarity and stability of Tn5 insertion mutations are among the topics discussed . Examples are cited from the published literature which illustrate the applications of Tn5 mutagenesis to the analysis of cloned prokaryotic and eukaryotic genes . A methods section is included which outlines precisely how to carry out transposon Tn5 mutagenesis analysis of cloned DNA segments. Nucleic Acids Res, 1984 Jan 25, 12(2), 945 - 58 Structure of the chloroplast gene for the precursor of the Mr 32,000 photosystem II protein from mustard (Sinapis alba L.); Link G et al.; The nucleotide sequence of the mustard chloroplast gene for the precursor of the Mr 32,000 photosystem II protein is presented . A comparison with the corresponding genes from spinach and Nicotiana debneyi (14) reveals less than 5% nucleotide divergence in the coding region . The derived protein of mustard differs from the corresponding proteins by three amino acid positions at the C-terminus . We have defined the presumed transcription start and termination sites of the mustard gene . Upstream from the start site are sequences typical of a prokaryotic promoter and, also, a sequence that resembles the eukaryotic 'TATA' box . A search for intrastrand base pairing revealed stem-loop secondary structure at the transcription start and termination sites and in the region preceding the presumed promoter . This latter region is a 69-base-pair sequence element unique to the 5'flanking sequence of the mustard gene. J Theor Biol, 1984 Jan 21, 106(2), 171 - 82 Self-transcription: RNA polymerase transcription of its own genes, and its role in cellular differentiation and cell cycling; Sanders DA; The concept of RNA polymerase self-transcription, where eukaryotic RNA polymerase II and prokaryotic holoenzyme are responsible for transcription of their own genes, would give these enzymes a unique role in the cellular transcriptional and translational machinery . This self-transcriptional ability would equip a cell with an exquisite mechanism of autogenous regulation for the appearance of these transcriptional units . Such a mechanism could allow layering of other transcriptional control pathways upon the RNA polymerase self-transcriptional pathway, thus forming a complex array of mechanisms to regulate transcription of genes concerned with cellular differentiation and cell cycling . It is proposed that RNA polymerase self-transcription is the central control point of gene expression in cellular differentiation and for cell cycling, thus fulfilling the role of an intrinsic biological clock. Nature, 1984 Jan 19-25, 307(5948), 292 - 4 Transposition of Tn554 does not generate a target duplication; Murphy E et al.; Transposable elements from prokaryotic and eukaryotic organisms are discrete DNA segments bounded by inverted or directly repeated sequences that insert into non-homologous DNA in a reaction that is independent of the general recombination functions of the host . The mechanisms proposed generally involve a staggered double-stranded scission of the target DNA, ligation to the nicked ends of the transposable element, and replication of the element, resulting in the generation of a directly repeated oligonucleotide target sequence flanking the new copy of the element . Most transposons have a relatively low degree of target site specificity coupled with a low insertion frequency . Tn554, a Staphylococcus aureus transposon which specifies resistances to erythromycin and spectinomycin, displays an unusually high degree of insertion specificity . Tn554 transposes with high efficiency to a unique ('primary') site in the S . aureus chromosome and only rarely (less than 10(-6) per transductant) to other, secondary sites . We report here the nucleotide sequences surrounding the junctions of Tn554 in three independent 'primary' insertions and two 'secondary' insertions of the transposon . Two unusual features are revealed: first, the termini of Tn554 contain neither inverted nor directly repeated sequences . Second, transposition of Tn554 does not generate the short direct repeats of the target DNA that are characteristic of other transposable elements . These results suggest that the mechanism of Tn554 insertion may be significantly different from that of other transposons. Nature, 1984 Jan 12-18, 307(5947), 185 - 7 Similarity of the Cin1 repetitive family of Zea mays to eukaryotic transposable elements; Shepherd NS et al.; It has been suggested that the middle repetitive class of sequences that make up a large proportion of the eukaryotic genome have been amplified and dispersed by DNA transposition . Transposition is a phenomenon first postulated by Barbara McClintock on the basis of her genetic analysis of mutants in Zea mays . Since then, DNA transposition has been studied genetically in various plant systems and is well documented on the molecular level in both prokaryotes and eukaryotes . This has included the isolation of DNA inserts at various loci in several plants; however, the prevalence of transposition in plants is not established . We report here DNA nucleotide sequence data which show that some members of the Cin1 middle repetitive family of maize have features characteristic of known transposable elements . One cloned Cin1 repeat has a 6-base pair (bp) perfect inverted repeat sequence at its ends . The terminal five base pairs (5' TGTTG . . . CAACA 3') are identical to the termini of Drosophila copia transposable elements . Two other Cin1 alleles are flanked by 5-bp direct repeats . A comparison is made with the long terminal repeat (LTR) of the copia-Ty1-retrovirus families of moveable genetic elements. FEBS Lett, 1984 Jan 9, 165(2), 175 - 9 Immunocytochemical localization of the elongation factor Tu in E . coli cells; Schilstra MJ et al.; The localization of the elongation factor Tu (EF-Tu) in ultrathin cryosections of E . coli cells was determined with the electron microscope using a highly specific immunological labelling technique . EF-Tu is distributed almost homogeneously throughout the cytoplasm . Although it has often been suggested that EF-Tu could be part of a putative prokaryotic cytoskeleton, we did not find any evidence for supramolecular assemblies, such as fibres or filaments, containing a large amount of EF-Tu . EF-Tu was not observed in association with the outer cell membrane and periplasmic space . A topological relationship with the inner membrane is not apparent in our micrographs . In cells in which the EF-Tu level is raised significantly, the protein piles up in discrete cell regions. Eur J Biochem, 1984 Jan 2, 138(1), 193 - 200 Proteins from the prokaryotic nucleoid . High-resolution 1H NMR spectroscopic study of Escherichia coli DNA-binding proteins NS1 and NS2; Paci M et al.; The 1H-NMR spectra of the two Escherichia coli basic, low-Mr (approximately equal to 9000) DNA-binding proteins NS1 and NS2 and of their native complex NS were studied at 400 MHz and a number of resonances and resonance peaks were assigned . As in the case of some eukaryotic histones, the presence of a large number of high-field perturbed Phe resonances, several shielded and deshielded methyl resonances and backbone NH protons quite inaccessible to the solvent clearly indicate the existence of extensive tertiary and, even more so, quaternary structures involving hydrophobic interactions . These structures are lost upon heating, but readily reform upon cooling . Spectral differences between NS1, NS2 and NS and the greater thermal stability of NS indicate that molecules of the heterologous subunits (NS1 and NS2) aggregate (dimerize) preferentially in comparison to the self-aggregation of the homologous subunits . Unlike those of the eukaryotic histones, the tertiary and quaternary structures of NS are insensitive to extensive variations of the ionic strength. Br J Cancer Suppl, 1984, 6, 7 - 11 Subcellular lesions: the current position; Cramp WA et al.; There continues to be an oversimplification of the approach to correlate cellular lesions with radiation induced cell death . Both in the prokaryotic and eukaryotic cell the relationship between vital macromolecules such as DNA, RNA, membrane and proteins is not yet fully understood either in a structural or functional sense . These macromolecules are often closely associated and interdependent . In spite of these recognised relationships much work is still devoted to measuring relatively early changes induced only in the DNA molecule . However, at the present time the quaternary structure of DNA and its closely neighbouring macromolecules is becoming better defined, and disturbances in these vital interrelationships may prove to be the most important radiation lesions . In the attempts to relate identifiable radiation damage to cell malfunction several criteria must be applied . For instance, the measured lesions must exhibit sensitization, protection and shoulder changes in response to the variety of agents and conditions which produce these phenomena at cellular level . In addition the radiation doses employed to produce measurable change must be within the same dose range as those used to study cellular and tissue effects . In much of the published work these criteria have not been applied. Proc Natl Acad Sci U S A, 1984 Jan, 81(2), 400 - 4 Microinjected pBR322 stimulates cellular DNA synthesis in Swiss 3T3 cells; Hyland JK et al.; When pBR322 is manually microinjected into the nuclei of quiescent Swiss 3T3 cells it stimulates the incorporation of {3H}thymidine into DNA . The evidence clearly shows that this increased incorporation that is detected by in situ autoradiography in microinjected cells represents cellular DNA synthesis and not DNA repair or plasmid replication . The effect is due to pBR322 and not due to impurities, mechanical perturbances due to the microinjection technique, or aspecific effects . This stimulation is striking in Swiss 3T3 cells . Some NIH 3T3 cells show a slight stimulation, but hamster cells, derived from baby hamster kidney (BHK) cells, are not stimulated when microinjected with pBR322 . The preliminary evidence seems to indicate that the integrity of the pBR322 genome is important for the stimulation of cellular DNA synthesis in quiescent Swiss 3T3 cells . These results, although of a preliminary nature, are of interest because they indicate that a prokaryotic genome may alter the cell cycle of mammalian cells . From a practical point of view the stimulatory effect of microinjected pBR322 on cellular DNA synthesis has a more immediate interest, because pBR322 is the vector most commonly used for molecular cloning and 3T3 cells are very frequently used for gene transfer experiments. Orig Life, 1984, 14(1-4), 513 - 22 Present state of the coacervate-in-coacervate theory; origin and evolution of cell structure; Novak VJ; In agreement with the views of Oparin, Fox, Dose etc., the theory assumes that coacervation of protein-like polyaminoacids began with their accumulation along the coasts of the Archaic water basins . Unlike the above authors, however, the present author views the original coacervates as a suitable "culture medium" from which the first polynucleotides originated and their partial replication started . Their base sequence was not fortuitous, but determined by the proteinoids on the basis of their mutual affinity . The polyfunctional enzymic activity of the proteinoids catalyzed their replication as well as other activities . Around the replicating DNA molecules secondary coacervates (coacervates in coacervates) accumulated which developed gradually to the first prokaryotic cells . Their most probable evolution to the first eukaryotic organisms is discussed on the basis of the modified Studitsky's synbacteriogenesis theory. Orig Life, 1984, 14(1-4), 323 - 34 The evolution of prebiological self-organization: probable colloid-chemical evolution of first prokaryotic cells; Liebl V et al.; This is an attempt to analyse the mechanisms of self-assembly in the course of the origin and early evolution of life on the Earth . A special attention is paid to the investigation of transient stages between the physico-chemical and biological bases of self-assembly, including experimental models and paleontological results . The theory of coacervate-in-coacervate is discussed from the point of view of evolution of first procaryotic cells . Many of the high developed structures of the contemporary cells, such as ribosomes, chromosomes, lipid membranes, some other organelles etc., are claimed to posses a rudimentary polyionic coacervate character. J Mol Evol, 1984, 20(2), 175 - 86 The alignment of sets of sequences and the construction of phyletic trees: an integrated method; Hogeweg P et al.; In this paper we argue that the alignment of sets of sequences and the construction of phyletic trees cannot be treated separately . The concept of 'good alignment' is meaningless without reference to a phyletic tree, and the construction of phyletic trees presupposes alignment of the sequences . We propose an integrated method that generates both an alignment of a set of sequences and a phyletic tree . In this method a putative tree is used to align the sequences and the alignment obtained is used to adjust the tree; this process is iterated . As a demonstration we apply the method to the analysis of the evolution of 5S rRNA sequences in prokaryotes. J Mol Evol, 1984, 20(2), 111 - 9 Strong doublet preferences in nucleotide sequences and DNA geometry; Nussinov R; Analysis of the sequence data available today, comprising more than 500,000 bases, confirms the previously observed phenomenon that there are distinct dinucleotide preferences in DNA sequences . Consistent behaviour is observed in the major sequence groups analysed here in prokaryotes, eukaryotes and mitochondria . Some doublet preferences are common to all groups and are found in most sequences of the Los Alamos Library . The patterns seen in such large data sets are very significant statistically and biologically . Since they are present in numerous and diverse nucleotide sequences, one may conclude that they confer evolutionary advantages on the organism . In eukaryotes RR and YY dinucleotides are preferred over YR and RY (where R is a purine and Y a pyrimidine) . Since opposite-chain nearest-neighbour purine clashes are major determinants of DNA structure, it appears that the tight packaging of DNA in nucleosomes disfavors, in general, such (YR and RY) steric repulsion. Nauchnye Doki Vyss Shkoly Biol Nauki, 1984, (5), 5 - 20 {Status and developmental prospects of microbiology}; Egorov NS et al.; The achievements of microbiology in the field of chemistry studying, molecular biology and cellular structure of bacteria are reflected in this review . The peculiarities of energetic, synthetic processes in prokaryotes and also the different methods of regulation of their metabolism have been shown . The achievements in the field of new strains construction and creation of biocatalysts on the basis of immobilized cells and enzymes for the biotechnological purposes have been elucidated . The role of microbiology in solving such social problems as the purification of environment from pollution, replenishing the resources of energy and protein which are rapidly exhausted has been shown. Oxf Surv Eukaryot Genes, 1984, 1, 1 - 35 The Drosophila mitochondrial genome; Clary DO et al.; The mitochondrial genome of Drosophila yakuba is a circular DNA molecule of 16019 nucleotide pairs . The sequence contains the genes for two rRNA molecules, 22 tRNA molecules, five known polypeptides (cytochrome b, cytochrome c oxidase subunits I, II, III and ATPase subunit 6) and eight unidentified polypeptides (URF1, 2, 3, 4L, 4, 5, 6 and A6L) . Between the tRNA(ile) and small rRNA genes there occurs a sequence of 1077 nucleotides that is 92.8 per cent A + T and lacks reading frames greater than 123 nucleotides . Replication of the molecule originates in this A + T-rich region and proceeds toward the small rRNA gene . Non-coding nucleotides between genes are either absent or occur in low numbers (1 to 31) . A sequence equivalent in size and secondary structure potential to the sequence associated with the initiation of second strand synthesis in mammalian mtDNA is missing in Drosophila mtDNA . While the genes found in D . yakuba and mammalian mtDNAs are the same, the relative arrangement of many of these genes differs considerably in the two molecules . The proportions of the two strands of the D . yakuba molecule which serve as template for transcription of genes are approximately equal . This contrasts with the situation in mammalian mtDNAs where all genes except those for URF6 and eight tRNAs are transcribed from one strand . The dihydrouridine and T psi C loops of D . yakuba mt-tRNA genes are highly variable in size, and among these genes there is a general deficiency of nucleotides which are highly conserved in prokaryotic and eukaryotic nuclear-coded tRNAs . The D . yakuba tRNA(AGYser) gene is unusual in that an eleven nucleotide loop replaces the dihydrouridine arm . D . yakuba mitochondrial polypeptide genes utilize 59 sense codons . However, 93.8 per cent of all codons used end in A or T . Unique variations occur in the Drosophila mitochondrial genetic code . AGA appears to specify serine rather than arginine as in the standard code, or termination as in the mammalian mitochondrial code . The Drosophila COI gene lacks a standard translation initiation codon, and may utilize a four nucleotide codon ATAA for that purpose . As in other metazoan mitochondria, TGA and ATA specify tryptophan and methionine, respectively . As a tRNA with an anticodon (TCT) specific for AGA codons does not appear to be encoded in D . yakuba mtDNA, it seems likely that the GCU anticodon of the D . yakuba tRNA which recognizes AGY (serine) codons can also recognize AGA.(ABSTRACT TRUNCATED AT 400 WORDS) J Cell Sci Suppl, 1984, 1, 21 - 9 DNA supercoiling and its effects on the structure of DNA; Wang JC; In prokaryotic organisms, there is strong evidence that the DNA is underwound or negatively supercoiled . The degree of supercoiling of intracellular DNA is less certain, and various estimates that can be made from existing data place the specific linking difference (superhelical density) of intracellular DNA in prokaryotes around -0.04 . The effects of negative supercoiling on DNA structure are illustrated by the flipping of alternating C-G or T-G sequences from right-handed B-helical form to the left-handed Z-helical form . For a plasmid containing a 42 base-pair alternating C-G insert, the B-to-Z transition occurs at a specific linking difference of 0.031 in a dilute aqueous buffer; the same transition occurs at a specific linking difference of -0.041 for a plasmid containing a 42 base-pair alternating T-G insert . The probing of the structure of a particular sequence of intracellular DNA is discussed. Int J Biochem, 1984, 16(12), 1193 - 9 Structural and genetic relationships between cytosolic and mitochondrial isoenzymes; Doonan S et al.; The most common type of genetic relationship between cytosolic and mitochondrial isoenzymes will probably be found to be divergent evolution from a common ancestral form . This is firmly established for the aspartate aminotransferases and less directly so in other cases . The two isoenzymes of aspartate aminotransferase have evolved at roughly equal rates at the level of total amino acid sequence but certain limited surface regions of the mitochondrial form have been much more highly conserved than corresponding regions in the cytosolic protein; these regions probably play a role in topogenesis of the mitochondrial isoenzyme . It is of interest that nearly all mitochondrial proteins are initially synthesised as precursors of molecular weight greater than the mature forms . In the case of aspartate aminotransferase, and possibly of other such isoenzymes, the N-terminus of the mature protein is nearly coincident with that of the cytosolic isoenzyme . Hence during evolution either the gene for the mitochondrial isoenzyme has gained an extra coding region for this N-terminal extension or, less likely, the structural gene for the cytosolic form has suffered a sizeable terminal deletion . Cytosolic and mitochondrial superoxide dismutases have not shared a common ancestral form as shown by the fact that their primary structures are completely unrelated . On the other hand, the mitochondrial and prokaryotic enzymes are clearly related . There is now, however, evidence to suggest that some prokaryotes possess a copper/zinc enzyme related to the eukaryotic cytosolic form . Hence the possibility arises that primitive prokaryotes possessed both proteins . The copper/zinc superoxide dismutase has been retained in the cytosol of eukaryotic cells and a few bacterial species.(ABSTRACT TRUNCATED AT 250 WORDS) Adv Protein Chem, 1984, 36, 1 - 78 Ribosomal proteins: their structure and spatial arrangement in prokaryotic ribosomes; Giri L et al.; During the last 15 years of ribosomal protein study, enormous progress has been made . Each of the proteins from E . coli ribosomes has been isolated, sequenced, and immunologically and physically characterized . Ribosomal proteins from other sources (e.g., from some bacteria, yeast, and rat) have been isolated and studied as well . Several proteins have recently been crystallized, and from the X-ray studies it is expected that much important information on the three-dimensional structure will be forthcoming . Many other proteins can probably be crystallized if suitable preparative procedures and crystallization conditions are found . Tremendous progress has also been made in deciphering the architecture of the ribosome . A battery of different methods has been used to provide the nearest neighbor distances of the ribosomal proteins in situ . Definitive measurements are now emanating from neutron-scattering experiments which also promise to give reasonably accurate radii of gyration of the proteins in situ . In turn, refined immune electron microscopy results supplement the neutron-scattering data and also position the proteins on the subunits themselves . This cannot be done by the other methods . Determination of the three-dimensional RNA structure within the ribosome is still in its infancy . Nonetheless, it is expected that by combining the data from protein-RNA and from RNA-RNA cross-linking studies, the structure of the RNA in situ can be unraveled . Of great interest is the fact that ribosomal subunits and ribosomes themselves have now been crystallized, and low-resolution structural maps have already been obtained . However, to grow suitable crystals and to resolve the ribosomal structure at a sufficiently high resolution remains a great challenge and task to biochemists and crystallographers. Mol Cell Biochem, 1984, 59(1-2), 11 - 32 Mechanism, regulation and physiological significance of the loop diuretic-sensitive NaCl/KCl symport system in animal cells; Saier MH Jr et al.; Investigations in numerous laboratories have characterized a salt transport system, present in many animal cell types, which catalyzes the transmembrane transport of NaCl and KCl in a tightly coupled process . The system is inhibited by loop diuretics such as furosemide and bumetanide . This transport system has been designated the loop diuretic-sensitive NaCl/KCl symporter . It has been implicated in transepithelial salt secretion and absorption as well as in cell volume regulation, and it may be defective in patients suffering from essential hypertension . This review serves to evaluate research conducted to date regarding the mechanism, mode of regulation, and physiological significance of the transport system . Ion binding specificities and absolute binding constants for all three naturally occurring ions have been determined in one cell system, the MDCK kidney epithelial cell line . In that same cell line, substrate binding was shown to exhibit apparent cooperativity . although a few reports suggest unidirectional transport of ions via this system under certain conditions, the consensus of reports indicates fully reversible, bidirectional salt transport with the direction of net flux determined by the magnitudes of the gradients of the three transported ions . Growth of cells in media containing a low concentration of K+ (less than 0.25 mM) allows selection of mutants lacking or defective in the symporter . Kinetic analyses with the MDCK cell line have shown that the symporter catalyzes accelerative exchange transport . However, exchange transport of one ion in the absence of one of the other two ionic substrates has not been documented . Comparison with other well-characterized transmembrane transport systems has shown that the characteristics of the NaCl/KCl symporter most resemble those of two-species facilitators (chemiosmotically-coupled symporters) found in prokaryotes and eukaryotes alike . these two-species facilitators consist of a single transmembrane protein and may function by a carrier-type mechanism as originally proposed by Peter Mitchell . A molecular model for the NaCl/KCl symporter is presented and discussed . Activation of symport activity requires ATP and probably occurs by a protein kinase-catalyzed mechanism . In some cell types activation is cyclic AMP dependent . ATP hydrolysis is not stoichiometric with transport . Phosphorylation of an integral membrane protein with an apparent size of 240 000 daltons correlates with activation of transport . It is postulated that this protein is the loop diuretic-sensitive NaCl/KCl symporter. Ciba Found Symp, 1984, 102, 233 - 45 Accessory DNAs in the bacterial gene pool: playground for coevolution; Hartl DL et al.; Chemostat studies of bacteria that harbour the prokaryotic transposable elements Tn5 and Tn10 and the temperate phages lambda, Mu, P1 and P2 have shown that these accessory DNA elements confer a selective advantage on their hosts . We propose that similar selective effects provided the initial impetus for the evolution of nascent accessory DNA elements in primitive bacterial populations . In subsequent evolution the elements acquired or perfected the 'selfish' characteristics of over-replication and horizontal transmission . Such selfish traits led to the dissemination of accessory DNAs among commensal strains, species and genera, genetically interconnecting them to create a 'commonwealth' of species that potentially share a common gene pool . The involvement of accessory DNAs in genetic exchange provides selection at the population level for refinement and diversification of the elements and for regulation of their replication, transposition and transfer among cells . The diversity of intracellular environments encountered by the elements imposes constraints on their evolution while at the same time altering the selection pressures operating on conventional chromosomal genes . This process of coevolution of accessory DNAs with the genomes of their diverse hosts has led to a unique population structure and mechanism of genetic exchange among bacteria, which constitutes the most effective adaptive strategy yet devised by selection. Cytogenet Cell Genet, 1984, 38(3), 227 - 34 Plasmid, phage, and genomic DNA-mediated transfer and expression of prokaryotic and eukaryotic genes in cultured human cells; Srivatsan ES et al.; Transfection of mammalian cells with genomic DNA and cloned genes is now relatively routine . However, the vast majority of studies have used rodent cells as recipients . Here we describe efficient transfection of two human cell lines, the hypoxanthine guanine phosphoribosyltransferase (HPRT)-deficient HeLa line, D98/AH-2, and the adenine phosphoribosyltransferase (APRT)-deficient HT1080 line, HTD114 . D98/AH-2 cells were transfected with the pSV2-gpt plasmid of Mulligan and Berg, which contains the E . coli xanthine-guanine phosphoribosyltransferase (gpt) gene, and Gpt + transfectants were selected in HAT medium . HTD114 cells were transfected with (1) genomic hamster DNA, and ouabain resistant transfectants were selected in 5 X 10(-7)M ouabain; (2) with hamster and mouse genomic DNA, and Aprt + cells were selected in AAA medium; (3) with plasmids containing either the cloned hamster or mouse APRT genes, and Aprt + cells were selected; and (4) with phage particles containing a cloned mouse APRT gene, and Aprt + cells were selected . Transfection efficiencies ranged from 0.25 to 1.5 X 10(3) transfectants per microgram DNA, and in certain cases secondary transfections were done . Foreign DNA in recipients was detected by blot hybridization, and the expression of foreign genes was detected by cell growth in selective media and the expression of enzymes characteristic of the species of the donor DNA . The majority of transfectants showed stable expression of the transgenome. Proc Natl Acad Sci U S A, 1984 Jan, 81(2), 555 - 9 Mutational analysis of a regulatory region in bacteriophage lambda that has overlapping signals for the initiation of transcription and translation; Wulff DL et al.; The positively regulated PRE promoter of phage lambda structurally overlaps with the ribosome-binding and NH2-terminal coding region of the regulatory protein (cII) that activates PRE transcription . We have isolated and characterized 27 different point mutations that occur within the 36-base-pair overlapping region . A comparison of genetic crossover data with nucleotide separations as determined by DNA sequence analysis reveals that recombination frequencies are greatly depressed at very short distances . Moreover, recombination frequency is critically dependent upon the precise nucleotide sequence of the crossover region for distances of five nucleotides or less . The mutations define precise positions and sequences that are important to (i) PRE promoter function, (ii) translation of the cII gene, and (iii) cII gene function . Mutational changes that affect the function of one element in this region concomitantly define phenotypically silent alterations in the other two elements . Mutations deficient in promoter function (P-RE or cy) are clustered in two regions that lie approximately equal to 10 and approximately equal to 35 nucleotides before the initial base of PRE mRNA, analogous to mutations in other promoters . P-RE mutations in the -10 region alter bases that are conserved in prokaryotic promoters, but P-RE mutations in the -35 region do not affect bases that are normally conserved in other promoters . Several mutations deficient in cII gene activity affect the initiation of cII protein synthesis, including an A leads to G change four bases outside the cII coding region, and AUG leads to GUG, AUG leads to ACG, and AUG leads to AUA mutations in the initiation codon . In the region of overlap between the PRE promoter and the NH2-terminal region of the cII gene, most amino acid substitutions in the cII protein do not result in a loss of cII function, indicating that this region of the gene does not contain essential information for cII function . We suggest that the overlap itself is an evolutionarily conserved structure and that it somehow coordinates the bidirectional transcriptional and translational events that occur in this region. Adv Enzyme Regul, 1984, 22, 157 - 85 The occurrence and consequences of deoxyuridine in DNA; Richards RG et al.; Deoxyuridine can become resident in the DNA of prokaryotic and eukaryotic cells via two general mechanisms - deamination of cytosine to uracil, and nucleotide pool changes that lead to misincorporation of deoxyuridine in place of thymidine . In this paper we have examined the chemical basis of deamination reactions in DNA and discussed a possible mechanism for an increased rate of deamination by means of cross-strand protonation of cytosine by alkylated guanine . In addition, we have examined the genetic and drug-induced conditions that lead to dUMP misincorporation into DNA in place of thymidine and have presented experimental evidence indicating that the antifolate-induced lesion is a general drug-dose dependent lesion of human blood cells . Finally, the toxic and genetic impact of this lesion has been evaluated within the context of a review of the repair mechanisms elicited by dUMP in DNA. J Mol Evol, 1984-85, 21(3), 259 - 69 Comparison of the nucleotide sequence of soybean 18S rRNA with the sequences of other small-subunit rRNAs; Eckenrode VK et al.; We present the sequence of the nuclear-encoded ribosomal small-subunit RNA from soybean . The soybean 18S rRNA sequence of 1807 nucleotides (nt) is contained in a gene family of approximately 800 closely related members per haploid genome . This sequence is compared with the ribosomal small-subunit RNAs of maize (1805 nt), yeast (1789 nt), Xenopus (1825 nt), rat (1869 nt), and Escherichia coli (1541 nt) . Significant sequence homology is observed among the eukaryotic small-subunit rRNAs examined, and some sequence homology is observed between eukaryotic and prokaryotic small-subunit rRNAs . Conserved regions are found to be interspersed among highly diverged sequences . The significance of these comparisons is evaluated using computer simulation of a random sequence model . A tentative model of the secondary structure of soybean 18S rRNA is presented and discussed in the context of the functions of the various conserved regions within the sequence . On the basis of this model, the short base-paired sequences defining the four structural and functional domains of all 18S rRNAs are seen to be well conserved . The potential roles of other conserved soybean 18S rRNA sequences in protein synthesis are discussed. IARC Sci Publ, 1984, (63), 525 - 39 Strategies for the economic preparation of Epstein-Barr virus proteins of diagnostic and protective value by genetic engineering: a new approach based on segments of virus-encoded gene products; Wolf H et al.; Immunoprecipitation of Epstein-Barr viral proteins with various sera from normal adults, patients with fresh infectious mononucleosis or nasopharyngeal carcinoma was used to identify antigens which are of importance in the determination of immune status and characteristic of a particular disease . Some genes coding for of these antigens have been localized on the Epstein-Barr virus (EBV) genome by hybrid-selected translation . With the use of sequence data, these genes could then be subcloned from EBV DNA and expressed in eukaryotic and prokaryotic cells . Data on the expression are presented and the application of the methods described for the production of diagnostic reagents and vaccines is discussed. Mol Gen Genet, 1984, 197(3), 497 - 502 A Tn21 terminal sequence within Tn501: complementation of tnpA gene function and transposon evolution; Grinsted J et al.; The prokaryotic mercury-resistance transposon Tn501 contains a sequence, 80 nucleotides from one end, which is identical with an inverted terminal repeat (IR) of Tn21 . This Tn21 IR sequence is used when Tn21 complements a TnpA- derivative of Tn501, but not when Tn501 is used for the complementation . Complementation by Tn1721 shows a preference for the normal Tn501 IRs . The element (Tn820) transposed when Tn21 is used to complement a Hg- TnpR- TnpA- Res- deletion mutant of Tn501 contains the Tn21 IR sequence at one terminus and a Tn501 IR at the other . Transposition of Tn820 can be complemented by Tn501 and Tn1721, but at a much lower frequency than transposition of the parental element (Tn819) which has two Tn501 IRs . The relationship between the transposition functions of Tn501, Tn21 and Tn1721, and available nucleotide sequence data suggest that Tn501 evolved by the transposition of a Tn21-like element into another transposable element (similar to that found within Tn1721) followed by deletion of the Tn21-like transposition functions. Mol Gen Genet, 1984, 198(1), 84 - 9 Functional characterization of the prokaryotic mobile genetic element IS26; Iida S et al.; IS26L and IS26R are the 820 bp long elements found as direct repeats at both ends of the kanamycin resistance transposon Tn2680 . They can mediate cointegration in E . coli K12 which contains no IS26 in its chromosome . Cointegration occurs in rec+ or recA- strains with similar frequency . Upon cointegration mediated by either IS26R or IS26L, the element is duplicated and integrated into one of many different sites . Both IS26L and IS26R carry 14 bp perfect terminal inverted repeats and generate 8 bp direct repeats at their target sequences . Deletion formation mediated by IS26R was also observed . These functional and structural features of IS26 are characteristic of a prokaryotic mobile genetic element. CRC Crit Rev Biochem, 1984, 17(2), 153 - 215 Enzymology of DNA in replication in prokaryotes; Marians KJ; This review stresses recent developments in the in vitro study of DNA replication in prokaryotes . New insights into the enzymological mechanisms of initiation and elongation of leading and lagging strand DNA synthesis in ongoing studies are emphasized . Data from newly developed systems, such as those replicating oriC containing DNA or which are dependent on the lambda, O, and P proteins, are presented and the information compared to existing mechanisms . Evidence bearing on the coupling of DNA synthesis on both parental strands through protein-protein interactions and on the turnover of the elongation systems are analyzed . The structure of replication origins, and how their tertiary structure affects recognition and interaction with the various replication proteins is discussed. Mol Gen Genet, 1984, 197(1), 62 - 6 The E . coli K-12 chromosome flanked by two IS10 sequences transposes; Harayama S et al.; Transposon are commonly found among prokaryotes and usually range up to 20 kilobases . In this study, we were interested to determine whether a larger DNA segment could transpose . We observed that the E . coli K-12 chromosome, 4,000 kilobases in size, when flanked by two IS10 sequences, could transpose to pACYC177 at a frequency of 10(-8) per cell per generation . We suggest that this transposition event occurs independently of the size and without duplication of the entire DNA sequence flanked by the IS10 elements. CRC Crit Rev Biochem, 1984, 17(1), 45 - 71 Processing of tRNA in prokaryotes and eukaryotes; Deutscher MP; Considerable progress has been made in defining the steps in the conversion of a tRNA precursor to a mature tRNA . These steps, which differ in different systems, include removal of precursor-specific residues from the 5' and 3' termini of the initial transcript, addition of the 3'-C-C-A terminus, splicing of intervening sequences, and modification of nucleotide residues . Despite these advances in defining the "pathways" of tRNA processing, relatively little is known about most of the enzymes actually involved in these processing steps . In this article I describe the sequence of reactions needed to convert the initial tRNA transcript to a functional, mature tRNA, and discuss the specificity and properties of enzymes known to be involved in this process . In addition, I speculate on the expected specificities of other enzymes involved in tRNA processing which have not yet been identified, and on the structural organization of the processing machinery. J Mol Appl Genet, 1984, 2(5), 471 - 84 Analysis of two potential shuttle vectors containing herpes simplex virus defective DNA; Bear SE et al.; Two potential shuttle vectors which contained the identical herpes simplex virus type 1 (HSV-1) defective particle DNA (dDNA), but prokaryotic DNA of different origins, were examined for their stability when propagated in eukaryotic cells, and for their efficiency as shuttle vectors . Each chimeric molecule contained a 9.5 kilobase-pair (kb) EcoRI fragment (HSV12-7) representing a single unit of a class I HSV-1 dDNA . This dDNA was cloned into the bacteriophage lambda (lambda) vector lambda gtWES X lambda B' to create a 45.3 kb chimeric molecule (lambda gtWES::12-7), and into the plasmid vector pBR325, resulting in a 15.5 kb recombinant DNA molecule (pBR325::12-7) . Each of these DNA molecules was transfected independently into African green monkey kidney cells which were then infected with wild-type HSV-1 helper virus . Both chimeric molecules were replicated and packaged into HSV-1 virions . However, regions of the lambda gtWES::12-7 chimeric DNA were rapidly deleted and rearranged, whereas the plasmid/HSV-1 DNA molecules were less rearranged . No intact lambda gtWES::12-7 DNA was recovered from HSV-1 virions as detected by infectivity of in vitro packaged DNA . However, pBR325::12-7 DNA isolated from HSV-1 virions was able to transform E . coli to ampicillin resistance . These results suggest additional considerations when designing single units of HSV-1 dDNA for use as vectors to accommodate large fragments of DNA. Biochim Biophys Acta, 1983 Dec 30, 726(4), 245 - 64 Na+/H+ antiporters; Krulwich TA; Na+/H+ antiports or exchange reactions have been found widely, if not ubiquitously, in prokaryotic and eukaryotic membranes . In any given experimental system, the multiplicity of ion conductance pathways and the absence of specific inhibitors complicate efforts to establish that the antiport observed actually results from the activity of a specific secondary porter which catalyzes coupled exchanged of the two ions . Nevertheless, a large body of evidence suggests that at least some prokaryotes possess a delta psi-dependent, mutable Na+/H+ antiporter which catalyzes Na+ extrusion in exchange for H+; in other bacterial species, the antiporter my function electroneutrally, at least at some external pH values . The bacterial Na+/H+ antiporter constitutes a critical limb of Na+ circulation, functioning to maintain a delta mu Na+ for use by Na+-coupled bioenergetic processes . The prokaryotic antiporter is also involved in pH homeostasis in the alkaline pH range . Studies of mutant strains that are deficient in Na+/H+ antiporter activity also indicate the existence of a relationship, e.g., a common subunit or regulatory factor, between the Na+/H+ antiporter and Na+/solute symporters in several bacterial species . In eukaryotes, an electroneutral, amiloride-sensitive Na+/H+ antiport has been found in a wide variety of cell and tissue types . Generally, the normal direction of the antiport appears to be that of Na+ uptake and H+ extrusion . The activity is thus implicated as part of a complex system for Na+ circulation, e.g., in transepithelial transport, and might have some role in acidification in the renal proximal tubule . In many experimental systems, the Na+/H+ antiport appears to influence intracellular pH . In addition to a role in general pH homeostasis, such Na+-dependent changes in intracellular pH could be part of the early events in a variety of differentiating and proliferative systems . Reconstitution and structural studies, as well as detailed analysis of gene loci and products which affect the antiport activity, are in their very early stages . These studies will be important in further clarification of the precise structural nature and role(s) of the Na+/H+ antiporters . In neither prokaryotes nor eukaryotes systems is there yet incontrovertible evidence that a specific protein carrier, that catalyzes Na+/H+ antiport, is actually responsible for any of the multitude of effects attributed to such antiporters . The Na+-H+ exchange might turn out to be side reactions of other porters or the additive effects of several conductance pathways; or, as appears most likely in at least some bacteria and in renal tissue, the antiporter may be a discrete, complex carr J Biol Chem, 1983 Dec 25, 258(24), 15198 - 205 Enzyme action at 3' termini of ionizing radiation-induced DNA strand breaks; Henner WD et al.; gamma-Irradiation of DNA in vitro produces two types of single strand breaks . Both types of strand breaks contain 5'-phosphate DNA termini . Some strand breaks contain 3'-phosphate termini, some contain 3'-phosphoglycolate termini (Henner, W.D., Rodriguez, L.O., Hecht, S . M., and Haseltine, W . A . (1983) J . Biol . Chem . 258, 711-713) . We have studied the ability of prokaryotic enzymes of DNA metabolism to act at each of these types of gamma-ray-induced 3' termini in DNA . Neither strand breaks that terminate with 3'-phosphate nor 3'-phosphoglycolate are substrates for direct ligation by T4 DNA ligase . Neither type of gamma-ray-induced 3' terminus can be used as a primer for DNA synthesis by either Escherichia coli DNA polymerase or T4 DNA polymerase . The 3'-phosphatase activity of T4 polynucleotide kinase can convert gamma-ray-induced 3'-phosphate but not 3'-phosphoglycolate termini to 3'-hydroxyl termini that can then serve as primers for DNA polymerase . E . coli alkaline phosphatase is also unable to hydrolyze 3'-phosphoglycolate groups . The 3'-5' exonuclease actions of E . coli DNA polymerase I and T4 DNA polymerase do not degrade DNA strands that have either type of gamma-ray-induced 3' terminus . E . coli exonuclease III can hydrolyze DNA with gamma-ray-induced 3'-phosphate or 3'-phosphoglycolate termini or with DNase I-induced 3'-hydroxyl termini . The initial action of exonuclease III at 3' termini of ionizing radiation-induced DNA fragments is to remove the 3' terminal phosphate or phosphoglycolate to yield a fragment of the same nucleotide length that has a 3'-hydroxyl terminus . These results suggest that repair of ionizing radiation-induced strand breaks may proceed via the sequential action of exonuclease, DNA polymerase, and DNA ligase . The possible role of exonuclease III in repair of gamma-radiation-induced strand breaks is discussed. J Biol Chem, 1983 Dec 25, 258(24), 15365 - 70 Cleavage of DNA by mammalian DNA topoisomerase II; Liu LF et al.; Using the P4 unknotting assay, DNA topoisomerase II has been purified from several mammalian cells . Similar to prokaryotic DNA gyrase, mammalian DNA topoisomerase II can cleave double-stranded DNA and be trapped as a covalent protein-DNA complex . This cleavage reaction requires protein denaturant treatment of the topoisomerase II-DNA complex and is reversible with respect to salt and temperature . The product after reversal of the cleavage reaction remains supertwisted, suggesting that the two ends of the putatively broken DNA are held tightly by the topoisomerase . Alternatively, the enzyme-DNA interaction is noncovalent, and the covalent linking of topoisomerase to DNA is induced by the protein denaturant . Detailed characterization of the cleavage products has revealed that topoisomerase II cuts DNA with a four-base stagger and is covalently linked to the protruding 5'-phosphoryl ends of each broken DNA strand . Calf thymus DNA topoisomerase II cuts SV40 DNA at multiple and specific sites . However, no sequence homology has been found among the cleavage sites as determined by direct nucleotide-sequencing studies. J Theor Biol, 1983 Dec 21, 105(4), 707 - 14 Do stalled replication forks synthesize a specific alarmone? Varshavsky A. Potential causes of premature arrest of a replication fork in vivo include an encounter with a chemical lesion in the DNA, inhibition of one of the essential enzymes of the fork, and spontaneous failure of the fork due to its finite degree of processivity . I suggest that a premature arrest of either a eukaryotic or prokaryotic replication fork induces it to enter a different state in which the fork synthesizes a specific signal nucleotide ("alarmone") . One function of the postulated new alarmone would be to increase the probability of re-initiation of DNA replication, either in cis (at an origin proximal to a site of the fork arrest) or in trans (at many different origins) . An additional, mechanistically related function of the postulated alarmone could be to increase the probability of re-assembly of an arrested fork beyond an otherwise impassable DNA lesion . In case of multiple fork arrests, an alarmone-mediated increase in the probability of replicon reinitiation (disproportionate DNA replication) would result in gene amplification at many different loci, thereby increasing the probability of cell's survival in a cytotoxic medium . Other likely functions of a fork-produced alarmone may include stimulation of DNA repair pathways including excision repair.(ABSTRACT TRUNCATED AT 250 WORDS) Biochem Biophys Res Commun, 1983 Dec 16, 117(2), 464 - 9 Hydrodynamic properties and structure of the rat liver 12 S arginyl- and lysyl-tRNA synthetase complex; Dang CV et al.; Eukaryotic aminoacyl-tRNA synthetases occur in multienzyme complexes in contrast to their prokaryotic counterparts . A core 12 S rat liver complex (Mr 290,000) was recently purified to homogeneity consisting of two polypeptides with Mr 73,000 and 65,000 identified as lysyl- and arginyl-tRNA synthetase, respectively (Dang et al . (1982) Biochemistry 21,1959-1966) . Using the modified hydrodynamic theory of Kirkwood (Kirkwood, J.R . (1954) J . Polym . Sci . 12,1-14), we have determined that the model most consistent with the hydrodynamic properties of the 12 S complex is a tetrameric tetrahedral model. J Biol Chem, 1983 Dec 10, 258(23), 14466 - 77 Yeast carbamyl phosphate synthetase . Structure of the yeast gene and homology to Escherichia coli carbamyl phosphate synthetase; Lusty CJ et al.; A cloned fragment of yeast chromosomal DNA carrying the gene CPA2 coding for the large subunit of arginine-specific carbamyl phosphate synthetase has been sequenced . The cloned DNA has a 3,354-nucleotide long continuous reading frame coding for a polypeptide of 1,117 amino acids . The calculated molecular weight of the encoded polypeptide is 123,787, in good agreement with the reported molecular weight of the yeast carbamyl phosphate synthetase large subunit . The amino acid sequence of yeast carbamyl phosphate synthetase is homologous to the recently determined sequence of Escherichia coli carbamyl phosphate synthetase (Nyunoya, H., and Lusty, C . J . (1983) Proc . Natl . Acad . Sci . U . S . A . 80, 4629-4633) over almost the entire length of the protein . Like the E . coli large subunit, the yeast enzyme exhibits an extensive internal homology between its NH2- and carboxyl-terminal halves . The internal homology in both the yeast and E . coli proteins indicates that the gene coding for the large subunit of carbamyl phosphate synthetase was derived from a tandem duplication which occurred prior to the divergence of eukaryotes and prokaryotes. J Biol Chem, 1983 Dec 10, 258(23), 14091 - 7 Two ribonucleic acid-dependent nucleoside triphosphate phosphohydrolases from rat liver nuclei; Blanchard KL et al.; Two nucleic acid-dependent ATPases have been isolated from hypotonic extracts of rat liver nuclei and partially characterized . Both enzymes are active with RNA and DNA but are most active with RNA . The most abundant enzyme, ATPase I, is a microheterogeneous, monomeric protein that consists of at least three forms with apparent molecular weights from 53,000 to 60,000 . It specifically catalyzes the hydrolysis of ATP (or dATP) to ADP (or dADP) and Pi in the presence of Mg2+ ions and nucleic acid cofactor and has a Km for ATP of 0.15 mM . The other enzyme, ATPase II, consists of a single protein with an apparent molecular weight of 37,000 . It catalyzes the hydrolysis of all 4 ribonucleoside triphosphates and dATP to the corresponding nucleoside diphosphate and Pi . For both enzymes, nuclear ribonucleoprotein RNA and cytoplasmic poly(A+) RNA are particularly effective cofactors, while total polysomal RNA (primarily rRNA) is a poor cofactor . The properties of these enzymes make them appear similar to other eukaryotic nucleic acid-dependent ATPases that have been isolated but distinct from the prokaryotic enzyme, RNA synthesis termination factor rho . The biological role of these enzymes is unknown. Proc Natl Acad Sci U S A, 1983 Dec, 80(24), 7586 - 90 Expression of the chloramphenicol acetyltransferase gene in mammalian cells under the control of adenovirus type 12 promoters: effect of promoter methylation on gene expression; Kruczek I et al.; The effect of DNA methylation at specific promoter sites on gene expression was tested by using a sensitive and quantitative assay system . The plasmid pSVO CAT contains the prokaryotic gene chloramphenicol acetyltransferase (CAT) and a HindIII site in front of it for experimental promoter insertion . Upon insertion into pSVO CAT, the E1a and protein IX gene promoters from adenovirus type 12 (Ad12) DNA were capable of mediating CAT expression upon transfection in mouse cells . In many viral and nonviral eukaryotic genes, DNA methylation at highly specific sites in the promoter region can attain a regulatory function in gene expression . One of the important sites is the 5' C-C-G-G 3' sequence . The CAT-promoting activity of the early simian virus 40 promoter in plasmid pSV2 CAT is refractory to methylation by the Hpa II or Hha I DNA methyltransferase at 5' C-C-G-G 3' or 5' G-C-G-C 3' sequences, respectively, because this promoter lacks such sites . The CAT coding sequence of this plasmid carries four Hpa II and no Hha I sites . Methylation of the Hpa II sites in the coding region does not affect expression . The E1a promoter of Ad12 DNA comprising the leftmost 525 base pairs of the viral genome carries two 5' C-C-G-G 3' and three 5' G-C-G-C 3' sites upstream from the leftmost "TATA" signal . Methylation of the Hpa II or Hha I sites incapacitates this promoter . The promoter of protein IX gene of Ad12 DNA contains one 5' C-C-G-G 3' and one 5' G-C-G-C 3' site downstream and two 5' G-C-G-C 3' sites greater than 300 base pairs upstream from the TATA motif and probably outside the promoter . The protein IX promoter is not inactivated by methylation of these sites . These data demonstrate that critical 5' methylations in the promoter region decrease or eliminate transcription; methylations of sites too far upstream or probably any sites downstream from the TATA site do not affect expression. Proc Natl Acad Sci U S A, 1983 Dec, 80(23), 7298 - 302 Point mutations and DNA rearrangements 5' to the inducible qa-2 gene of Neurospora allow activator protein-independent transcription; Geever RF et al.; Expression of the qa-2 gene of Neurospora crassa normally requires a functional activator protein encoded by qa-1F . Twelve transcriptional mutants of the qa-2 gene have been isolated in qa-1F- strains, and these allow partial expression of qa-2 (1-45% of induced wild type) in the absence of functional activator protein . All 12 mutants have been characterized by genomic (Southern) blot hybridization and the DNAs of 5 have been cloned and sequenced . Eight mutations consist of large DNA rearrangements within a 500-base-pair region 5' to the qa-2 gene . One large rearrangement mutation, located 378 base pairs before the normal site of transcription initiation, causes exceptional levels of qa-2 transcription (45% of induced wild type) from near the normal initiation site . Two of the other four mutations cloned involve tandem duplications (68 and 84 base pairs) of the same upstream region (centered at nucleotide - 145), and two involve "point" mutations (at nucleotides -200 and -95) that closely flank the duplicated region . With one possible exception, none of the mutations appears to involve changes directly associated with RNA polymerase II binding and hence they differ from analogous mutations in comparable prokaryotic systems . The overall results suggest that at least some of the large DNA rearrangement mutations may be acting as upstream activator elements, possibly by juxtaposing enhancer-like sequences, whereas the duplications and point mutations may define a region of qa-2 regulation, for instance at the level of RNA polymerase II access. Nucleic Acids Res, 1983 Nov 25, 11(22), 8037 - 49 Secondary structure of the Dictyostelium discoideum small subunit ribosomal RNA; Olsen GJ et al.; We have used comparative analyses of prokaryotic and eukaryotic small subunit ribosomal RNAs to deduce a secondary structure for the Dictyostelium discoideum 18S rRNA . Most of the duplex regions are evolutionarily conserved in all organisms . We have taken advantage of the variation to the D . discoideum sequence (relative to the yeast and frog 19S rRNAs) to identify additional helical regions which are common to the eukaryotic 18S rRNAs. Science, 1983 Nov 18, 222(4625), 734 - 9 Studying promoters and terminators by gene fusion; Rosenberg M et al.; Prokaryotic gene control signals can be isolated, compared, and characterized by precise fusion in vitro to the Escherichia coli galactokinase gene (galK), which provides both a simple assay and genetic selection . This recombinant galK fusion vector system was applied to the study of promoters and terminators recognized by the Escherichia coli RNA polymerase . Three promoters created by mutation from DNA sequences having no promoter function were characterized . Mutations that inactivate promoter function were selected, structurally defined, and functionally analyzed . Similarly, transcription termination was examined, and mutations affecting terminator function were isolated and characterized. Biochem Biophys Res Commun, 1983 Nov 15, 116(3), 843 - 50 Induction by barbiturates of a cytochrome P-450-dependent fatty acid monooxygenase in Bacillus megaterium: relationship between barbiturate structure and inducer activity; Kim BH et al.; In a recent communication (Narhi, L . and Fulco, A.J . {1982} J . Biol . Chem . 257, 2147-2150) we found that a soluble cytochrome P-450-dependent fatty acid monooxygenase isolated from Bacillus megaterium ATCC 14581 could be induced about 28-fold by phenobarbital . We have now examined 19 barbiturates and found that 13 significantly induce the specific monooxygenase activity . Of these, 11 are more active than phenobarbital and three (secobarbital, thiamylal and methohexital) are more than 30 times as active on a molar basis . The dialkyl barbiturates without exception show an excellent correlation between increasing lipophilicity and increasing potency as inducers as do most of the barbiturates containing an aromatic substituent . Nevertheless, it is apparent that certain structural features involving factors other than lipophilicity are also necessary for induction . Our finding that barbiturates can cause the non-substrate induction of a cytochrome P-450-dependent monooxygenase in a prokaryote represents a unique discovery that may provide a relatively simple model for apparently similar induction systems in higher animals. Biochem Biophys Res Commun, 1983 Nov 15, 116(3), 1007 - 12 Sequence homology between prokaryotic and eukaryotic forms of serine hydroxymethyltransferase; Barra D et al.; The sequence of tryptic and chymotryptic peptides from cytosolic and mitochondrial rabbit liver serine hydroxymethyltransferase are compared to the proposed sequence of a protein coded for by the glyA gene of Escherichia coli . The E . coli glyA gene is believed to code for serine hydroxymethyltransferase . Extensive sequence homology between these peptides were found for the proposed E . coli enzyme in the aminoterminal two-thirds of the molecule . All three proteins have identical sequences from residue 222-231 . This sequence is known to contain the lysyl residue which forms a Schiff's base with pyridoxal-P in the two rabbit liver enzymes . These results support the interpretation that the proposed sequence of E . coli serine hydroxymethyltransferase is correct . The data also show that cytosolic and mitochondrial serine hydroxymethyltransferase are homologous proteins. Nucleic Acids Res, 1983 Nov 11, 11(21), 7287 - 302 Replication and expression in mammalian cells of transfected DNA; description of an improved erythrocyte ghost fusion technique; Wiberg FC et al.; After modification of an erythrocyte - ghost fusion technique, DNA can be transferred in large amounts to mammalian cells . The overall recovery permits analysis of transferred DNA immediately after fusion by e.g . Southern - blot hybridization and electron microscopy . In general more than 20% of the cells contain the transfected DNA in their nuclei within 4 hours post fusion . Expression of Polyoma T antigens is delayed, as compared to a normal virus infection, and is detected at about 60 hours after transfer of DNA . During the first days an increase in amount of transferred DNA could be detected which might be due to limited replication . To analyze the replication of hybrid DNA molecules consisting of Polyoma and prokaryotic plasmid DNA sequences, fusion was followed by a normal Polyoma virus infection . The resulting induction of cells to enter the S phase made possible replication analysis of transfected hybrid DNA . Replicating molecules of both the theta form and rolling - circle type were observed. J Biol Chem, 1983 Nov 10, 258(21), 12952 - 6 The amino acid sequence of D-ribose-binding protein from Escherichia coli K12; Groarke JM et al.; The amino acid sequence of the D-ribose-binding protein from Escherichia coli K12 was determined from the DNA sequence of the gene . Protein sequence analyses covering 80% of the protein were consistent with the sequence deduced from the DNA . The mature binding protein has 271 amino acid residues and shows substantial homology to D-galactose-binding protein . A signal peptide sequence of 23 or 25 residues was also deduced from the DNA sequence . It shows the characteristic features of prokaryotic signal peptides. Biochemistry, 1983 Nov 8, 22(23), 5306 - 15 Evolutionary aspects of accuracy of phenylalanyl-tRNA synthetase . Accuracy of fungal and animal mitochondrial enzymes and their relationship to their cytoplasmic counterparts and a prokaryotic enzyme; Gabius HJ et al.; Phenylalanyl-tRNA synthetases from mitochondria of yeast and hen liver resemble their corresponding cytoplasmic counterparts . Whereas slight intraspecies differences at the amino acid binding site, reflecting variations in the structures of these distinct enzymes, are exploitable by phenylalanine analogues, no intraspecies difference can be noted for the strategies to achieve the high fidelity of protein synthesis . While the yeast mitochondrial enzyme follows the pathway of posttransfer proofreading, the hen liver mitochondrial enzyme uses a tRNA-dependent pretransfer proofreading in the case of the natural amino acids . The accuracy of mitochondrial phenylalanyl-tRNA synthetases appears to be even better than the accuracy of the corresponding cytoplasmic enzymes . Interspecies rather than intraspecies differences for the functional role of certain amino acid residues of the enzymes further indicate the close relationship of the intracellular heterotopic isoenzymes . By use of a highly sensitive immunospotting procedure, common antigenic determinants are detected only within the enzymes from the two intracellular compartments of the same organism . The results suggest the origin of the cytoplasm-mitochondrion isoenzyme pair by independent gene duplication of the ancestral nuclear gene . A similarity of mitochondrial enzymes to the phenylalanyl-tRNA synthetase from Escherichia coli is not observed. Eur J Cell Biol, 1983 Nov, 32(1), 136 - 42 Electron microscopic study of eukaryotic 40S initiation complex in protein synthesis; Boublik M et al.; This electron microscopic study demonstrates that formation of a functional eukaryotic 40S initiation complex is accompanied by conformational changes which obscure the characteristic structural features of the 40S ribosomal subunits and of the initiation factor eIF-3, the only macromolecular components of the complex individually resolvable by conventional high resolution electron microscopy . The complex, characterized by a sedimentation coefficient of 46S, appears as a globular particle with a diameter of about 280 A and several characteristic protrusions and incisions . Similar structures were obtained with {40S X eIF-3} initiation complexes formed by interaction of eIF-3 from rabbit reticulocytes with 40S ribosomal subunits from either A . salina cysts or mouse liver . Incubation of eIF-3 with prokaryotic 30S subunits from E . coli produced no {30S X eIF-3} structures . The binding of eIF-3 to 40S subunits is weak, and both the {40S X eIF-3} and the complete 40S initiation complexes have to be stabilized by glutaraldehyde fixation . The extensive conformational changes associated with the complex formation preclude direct electron microscopic localization of eIF-3, a globular protein approximately 100 A in diameter, in the initiation domain of the 40S subunit. J Biochem (Tokyo), 1983 Nov, 94(5), 1457 - 64 Ferredoxin from Aphanothece halophitica, a unicellular blue-green alga: close relationship to ferredoxins from filamentous blue-green algae and phylogenetic implications; Hase T et al.; The amino acid sequence of a ferredoxin from a unicellular blue-green alga, Aphanothece halophitica, was established by the conventional methods . Total number of residues was 98 lacking only tryptophan . A most probable phylogenetic tree was constructed for 19 algal ferredoxins on the basis of an amino acid difference matrix made from the sequence comparison . A . halophitica has been classified as a unicellular blue-green alga in the same genus to which Aphanothece sacrum belongs, but the tree indicates A . halophitica ferredoxin to be very close to those of the members of filamentous blue-green algae . The tree divides prokaryotic and eukaryotic algal ferredoxins into several groups, suggesting that the ferredoxin phylogenetic tree reflects the evolutionary trails of various algae, which is also reflected in the structural characteristics, particularly in the presence of gaps . Other notable features are presented in considering algal taxonomy. Environ Health Perspect, 1983 Nov, 53, 163 - 7 In vitro assessment of asbestos genotoxicity; Daniel FB; Asbestos fibers are highly cytotoxic to cultured mammalian cells and produce chromosomal aberrations in several rodent cell types . There is some uncertainty in the literature as to whether these fibers are clastogenic to cultured human cells . Asbestos fibers do not produce either DNA damage or back mutations in prokaryotic assay systems, and they do not appear to cause DNA strand breaks in either rodent or human cells . The evidence that these fibers can produce either forward mutation or neoplastic transformation of mammalian cells is weak . Asbestos fibers are clearly oncogenic to humans and animals, but, except for clastogenic effects in rodent cells, there is little evidence for genotoxicity of fibers . It is reasonable to expect, therefore, that these materials may be oncogenic by virtue of mechanisms rather than as tumor initiators. Bioorg Khim, 1983 Nov, 9(11), 1544 - 57 {Statistical study of the nucleotide sequence of a prokaryotic promoter . Structural elements determining the efficacy of the transcription initiation stages}; Artem'ev IV et al.; Nucleotide sequences of 188 promoter-containing DNA regions have been studied by the computer statistic analysis . Undecanucleotide NTT(G/C)TTGACA(A/T) or (G/C) X TT(G/C)A(G/C)A(A/T)TT(G/T) (recognition site) and heptanucleotide RTATATR or TATAATR (initiation site) separated by 12-19 base pairs are characteristic of a "generalized" promoter structure . Promoters can function if a minimal level of correspondence for their recognition and initiation sites to a generalized structure is attained (the correspondence function value for the whole structure is not lower than 0,61; for the most effective promoters it may be equal to 1) . The transcription start is situated 3-9 base pairs after initiation site, 4-7 pairs distance being the most effective . Transcription can start from any nucleotide, preferably with A or G . The start from A is the most effective if it is contained within the CAC or CAT trinucleotides . The promoter efficiency is enhanced by some additional structural factors: the presence of an extended A-T rich region directly before the recognition site; availability of integral promoter structures or several RNA polymerase binding sites in the preceding nucleotide sequence . A characteristic feature of the promoter is the presence of either the dyadic axial symmetry elements in the initiation and recognition sites as well as in the intermediate region, or the A-T rich area in the latter. Biochem Int, 1983 Nov, 7(5), 557 - 68 Histones H3 and H2a are homologous to the lambda repressor and cro proteins in 22 residue segments implicated in DNA binding; Magnus KA et al.; The histones H3 and H2a from calf thymus are homologous to the repressor and cro repressor proteins of bacteriophage lambda in a 22-residue segment that has been implicated by mutational and model-building studies in DNA binding . In the lambda proteins this segment is folded into a helix-turn-helix unit of supersecondary structure, and we propose that the homologous regions in the histones possess the same fold . Homology was quantified with a unified procedure based on criteria of identity of key residues, primary structural homology and similarity of secondary structural potential . It has previously been shown that a set of other prokaryotic DNA-binding proteins have primary structural homology with the two lambda proteins . Homologies detected between the histones H4 and H2b and members of this set suggest that these histones also contain the putative DNA-binding fold. Gene, 1983 Nov, 25(1), 49 - 58 Escherichia coli plasmid vectors for high-level regulated expression of the bacteriophage lambda xis gene product; Abremski K et al.; The bacteriophage lambda Xis protein is one of the proteins required for site-specific excisive recombination by which the lambda prophage is excised from the Escherichia coli bacterial chromosome . We cloned the lambda xis gene under the control of several prokaryotic promoters to obtain a sufficient source of the protein for biochemical studies . Our results demonstrate that E . coli lac promoter and lambda pL promoter fusions to the xis gene produce high levels of Xis protein . Induction of the expression vectors results in a 10- to 50-fold increase in Xis activity . In addition, one of these plasmids allows the control of xis expression in vivo. Proc Natl Acad Sci U S A, 1983 Nov, 80(22), 6897 - 901 Partial cDNA sequence to a hamster gene corrects defect in Escherichia coli pyrB mutant; Davidson JN et al.; The first three enzymes of pyrimidine biosynthesis (carbamoyl-phosphate synthetase, aspartate carbamoyl-transferase, and dihydro-orotase) are carried on a multifunctional protein in mammalian cells and are on separate proteins in bacteria . A plasmid containing a cDNA sequence corresponding to 80% of a hamster mRNA for this protein was transformed into Escherichia coli mutants lacking aspartate carbamoyltransferase (pyrB) or dihydro-orotase (pyrC) . Only pyrB transformants were able to grow in the absence of uracil . Plasmid recovered from primary transformants was similar in size to the original plasmid and could yield prototrophs after secondary transformation of E . coli pyrB mutants . When cell extracts were prepared from pyrB transformants, high levels of aspartate carbamoyltransferase activity were found, and the enzyme had properties identical to the mammalian enzyme, including lack of allosteric regulation, precipitation by antiserum specific to the hamster multifunctional protein, and presence of a strong aggregation center . These results demonstrate that (i) a partial hamster protein can complement E . coli defective in pyrimidine biosynthesis, (ii) the order of the enzyme domains of the multifunctional protein is likely to be NH2-dihydro-orotase-carbamoyl-phosphate synthetase-aspartate carbamoyltransferase-COOH, and (iii) the enzyme domains appear to be self-contained at the DNA and protein levels . The protocol described here may be a general means for studying the domains of multifunctional proteins and for isolating other mammalian genes for which bacterial mutants have been prepared . It also permits study of the structure and function of the same gene in both prokaryotic and eukaryotic cells and may provide new insight into the evolution of complex genes. Biochemistry, 1983 Oct 25, 22(22), 5097 - 103 Fluorine-19 nuclear magnetic resonance studies of lipid fatty acyl chain order and dynamics in Acholeplasma laidlawii B membranes . A physical, biochemical, and biological evaluation of monofluoropalmitic acids as membrane probes; McDonough B et al.; Fluorine-19 nuclear magnetic resonance spectroscopy offers a number of unique advantages for studies of lipid fatty acyl chain order and dynamics in model and biological membranes . However, the germinal difluoromethylene fatty acids commonly employed as 19F membrane probes appear to appreciably perturb the organization of model membranes and biomembranes . We have thus synthesized a series of specifically labeled monofluoropalmitic acids and evaluated these as suitable membrane probes . Differential scanning calorimetric studies of aqueous dispersions of several bis-(monofluoropalmitoyl)phosphatidylcholines reveal that a fluorine substitution near the carbonyl group of palmitic acid has only a modest effect on the thermotropic phase behavior of these model membranes and that substitutions in the center or toward the methyl terminus are relatively nonperturbing . Moreover, all bis(monofluoropalmitoyl)phosphatidylcholines tested exhibit nearly ideal mixing in all proportions with dipalmitoylphosphatidylcholine . The thermotropic phase behavior of membranes of the simple, cell-wall-less prokaryote Acholeplasma laidlawii B is also not detectably altered by the presence of appreciable amounts of biosynthetically incorporated monofluoropalmitic acid . We also find that the biosynthetic incorporation of even large amounts of monofluoropalmitic acids into the membrane lipids of A . laidlawii B has no effect upon the growth and survival of this organism . The presence of exogenous monofluoropalmitic acids in the growth medium does not alter the polar head group composition or lipid/protein ratio of the A . laidlawii B membrane . In addition, all monofluoropalmitic acids tested are biosynthetically incorporated as well as palmitic acid itself and distribute relatively evenly between the various membrane glyco- and phospholipids.(ABSTRACT TRUNCATED AT 250 WORDS) Biochem Biophys Res Commun, 1983 Oct 14, 116(1), 327 - 34 A helix-destabilising protein from herpes simplex virus type I infected cells which specifically stimulates the virus induced DNA polymerase activity in vitro; Bruce CB et al.; We have isolated a