Trends Plant Sci, 1999 Mar, 4(3), 117 - 120 Is hexokinase really a sugar sensor in plants? Halford NG, Purcell PC, Hardie DG. The molecular mechanisms by which plant cells sense sugar levels are not understood, but current models (adapted from models for sugar sensing in yeast) favour hexokinase as the primary sugar sensor . However, the hypothesis that yeast hexokinase has a signalling function has not been supported by more recent studies and the idea that hexokinase is involved in sugar sensing in plants has yet to be proven. Trends Plant Sci, 1999 Mar, 4(3), 107 - 112 Function of the ubiquitin-proteosome pathway in auxin response; del Pozo JC et al.; Proteolysis of important regulatory proteins by the ubiquitin-proteosome pathway is a key aspect of cellular regulation in eukaryotes . Genetic studies in Arabidopsis indicate that response to auxin depends on the function of proteins in this pathway . The auxin transport inhibitor resistant 1 (TIR1) protein is part of a ubiquitin-protein-ligase complex (E3), known as SKP1 CDC53 F-boxTIR1 (SCFTIR1), that possibly directs ubiquitin-modification of protein regulators of the auxin response . In yeast, a similar E3 complex, SCFCDC4, is regulated by conjugation of the ubiquitin-related protein Rub1 to the Cdc53 protein . In Arabidopsis, the auxin-resistant1 (AXR1) gene encodes a subunit of the RUB1-activating enzyme, the first enzyme in the RUB-conjugation pathway . Loss of AXR1 results in loss of auxin response . These results suggest a model in which RUB1 modification regulates the activity of SCFTIR1, thereby directing the degradation of the repressors of the auxin response. Trends Cell Biol, 1999 May, 9(5), 166 - 9 Nedd4-like proteins: an emerging family of ubiquitin-protein ligases implicated in diverse cellular functions; Harvey KF et al.; The members of an emerging family of proteins similar to Nedd4 have a unique modular structure consisting of a Ca2+/lipid-binding domain, multiple protein-protein interaction modules and a ubiquitin-protein ligase domain . Although little is known about the physiological roles of these proteins, studies in both mammals and yeast are providing evidence that members of this family might be involved in diverse cellular functions, such as regulation of membrane channels and permeases, the cell cycle and transcription . This article attempts to bring together what is currently known about these evolutionarily conserved ubiquitin-protein ligases. Curr Opin Genet Dev, 1999 Apr, 9(2), 218 - 24 Telomeres and telomerase: broad effects on cell growth; Price CM; During the past year, major advances have been made in understanding the link between telomerase expression and cell immortality . Studies of yeast telomeres have revealed an unexpected role for the non-homologous end-joining machinery in telomere maintenance and have provided the first definitive evidence that telomeres play a critical role in meiosis . Identification of new telomere proteins has led to a better understanding of vertebrate telomere structure and function. Mol Microbiol, 1999 May, 32(3), 557 - 68 The multiply-regulated gabA gene encoding the GABA permease of Aspergillus nidulans: a score of exons; Hutchings H et al.; We describe the cloning, sequence and expression of gabA, encoding the gamma-amino-n-butyrate (GABA) permease of the fungus Aspergillus nidulans . Sequence changes were determined for three up-promoter (gabI ) and six gabA loss-of-function mutations . The predicted protein contains 517 residues and shows 30.3% overall identity with a putative GABA permease of Arabidopsis thaliana, 29.6% identity with the yeast choline transporter and 23.4% identity with the yeast UGA4 GABA permease . Structural predictions favour 11-12 transmembrane domains . Comparison of the genomic and cDNA sequences shows the presence of 19 introns, an unusually large number of introns for, we believe, any fungal gene . In agreement with the wealth of genetic data available, transcript level analyses demonstrate that gabA is subject to carbon catabolite and nitrogen metabolite repression, omega-amino acid induction and regulation in response to ambient pH (being acid-expressed) . In agreement with this, we report consensus binding sites 5' to the coding region, six each for CreA and AREA and one for PacC, the transcription factors mediating carbon catabolite and nitrogen metabolite repression and response to ambient pH respectively. J Biol Chem, 1999 May 14, 274(20), 14352 - 8 The autonomous transactivation domain in helix H3 of the vitamin D receptor is required for transactivation and coactivator interaction; Kraichely DM et al.; A ligand-inducible transactivation function (AF-2) exists in the extreme carboxyl terminus of the vitamin D receptor (VDR) that is essential for 1alpha,25-dihydroxyvitamin D3 (1,25-(OH)2D3)-activated transcription and p160 coactivator interaction . Crystallographic data of related nuclear receptors suggest that binding of 1, 25-(OH)2D3 by VDR induces conformational changes in the ligand-binding domain (LBD), the most striking of which is a packing of the AF-2 helix onto the LBD adjacent to helices H3 and H4 . In this study, a panel of VDR helix H3 mutants was generated, and residues in helix H3 that are important for ligand-activated transcription by the full-length VDR were identified . In particular, one mutant (VDR (Y236A)) exhibited normal ligand binding and heterodimerization with the retinoid X receptor (RXR) but was transcriptionally inactive . Yeast two-hybrid studies and in vitro protein interaction assays demonstrated that VDR (Y236A) was selectively impaired in interaction with AF-2-interacting coactivator proteins such as SRC-1 and GRIP-1 . These data indicate an importance of helix H3 in the mechanism of VDR-mediated transcription, and they support the concept that helix H3 functions in concert with the AF-2 domain to form a transactivation surface for binding the p160 class of nuclear receptor coactivators. Biochemistry, 1999 May 11, 38(19), 6093 - 103 Role of unusual amino acid residues in the proximal and distal heme regions of a plant P450, CYP73A1; Schalk M et al.; CYP73A1 is a typical plant P450 in terms of its function and primary sequence . The enzyme catalyzes the 4-hydroxylation of trans-cinnamic acid, the first oxidative step in the phenylpropanoid pathway . Its primary protein sequence exhibits some particular landmarks which are characteristic of plant P450 enzymes . The most interesting is a proline residue (Pro448), very unusual in animal P450s, just C-terminal to the invariant heme-binding cysteine . To determine the role of this proline, we substituted it with valine, isoleucine, or phenylalanine, residues found in animal P450s, using site-directed mutagenesis . Expression of the wild type and mutants in yeast indicated that replacement of Pro448 led to disruption of the heme-protein interaction, loss of catalytic activity, and either impaired expression or destabilization of the apoprotein . Pro448 is thus essential for the correct insertion of heme in the apoprotein . Another typical feature of CYP73A proteins is the presence of an alanine-alanine motif (Ala306-Ala307) on the presumed N-terminal edge of the cleft in the central part of the I helix . This cleft faces the iron on the distal side of the heme and is proposed to be essential for catalysis . Substitution of each or both Ala306 and Ala307 residues with glycines showed that they are critical for the stability of the protein and influence the positioning of the substrate in the active site . Results are discussed with reference to the structural X-ray data that are available for bacterial P450 proteins. Ann Neurol, 1999 May, 45(5), 673 - 5 Direct evidence that mitochondrial iron accumulation occurs in Friedreich ataxia; Delatycki MB et al.; Friedreich ataxia (FRDA) is due to mutations in the FRDA gene (FRDA) . When the gene homologous to FRDA is knocked out in yeast, there is accumulation of iron in mitochondria and reduced respiratory function . So far, there is only indirect evidence to support the hypothesis that FRDA is due to accumulation of mitochondrial iron leading to increased production of free radicals . We show here that mitochondrial iron is significantly higher in fibroblasts from patients with FRDA than in control fibroblasts . This is the first direct evidence that the findings in yeast are reproducible in cells from patients with FRDA. Cell, 1999 Apr 30, 97(3), 383 - 93 RESPONSIVE-TO-ANTAGONIST1, a Menkes/Wilson disease-related copper transporter, is required for ethylene signaling in Arabidopsis; Hirayama T et al.; Ethylene is an important regulator of plant growth . We identified an Arabidopsis mutant, responsive-to-antagonist1 (ran1), that shows ethylene phenotypes in response to treatment with trans-cyclooctene, a potent receptor antagonist . Genetic epistasis studies revealed an early requirement for RAN1 in the ethylene pathway . RAN1 was cloned and found to encode a protein with similarity to copper-transporting P-type ATPases, including the human Menkes/Wilson proteins and yeast Ccc2p . Expression of RAN1 complemented the defects of a ccc2delta mutant, demonstrating its function as a copper transporter . Transgenic CaMV 35S::RAN1 plants showed constitutive expression of ethylene responses, due to cosuppression of RAN1 . These results provide an in planta demonstration that ethylene signaling requires copper and reveal that RAN1 acts by delivering copper to create functional hormone receptors. Int J Syst Bacteriol, 1999 Apr, 49 Pt 2, 351 - 9 Thermococcus barophilus sp . nov., a new barophilic and hyperthermophilic archaeon isolated under high hydrostatic pressure from a deep-sea hydrothermal vent; Marteinsson VT et al.; A novel barophilic, hyperthermophilic, anaerobic sulfur-metabolizing archaeon, strain MPT (T = type strain), was isolated from a hydrothermal vent site (Snakepit) on the Mid-Atlantic Ridge (depth, 3550 m) . Enrichments and isolation were done under 40 MPa hydrostatic pressure at 95 degrees C . Strain MPT was barophilic at 75, 80, 85, 90, 95 and 98 degrees C, and was an obligate barophile between 95 and 100 degrees C (Tmax) . For growth above 95 degrees C, a pressure of 15.0-17.5 MPa was required . The strain grew at 48-95 degrees C under atmospheric pressure . The optimal temperature for growth was 85 degrees C at both high (40 MPa) and low (0.3 MPa) pressures . The growth rate was twofold higher at 85 degrees C under in situ hydrostatic pressure compared to at low pressure . Strain MPT cells were motile, coccoid, 0.8-2.0 microns in diameter and covered by a hexagonal S-layer lattice . The optimum pH and NaCl concentration for growth at low pressure were 7.0 and 20-30 g l-1, respectively . The new isolate was an obligate heterotroph and utilized yeast extract, beef extract and peptone for growth . Growth was optimal in the presence of elemental sulfur . Rifampicin and chloramphenicol inhibited growth . The core lipids consisted of a major archaeol and a complex lipid pattern consisting of a major phospholipid . The DNA G + C content was 37.1 mol% . Sequencing of the 16S rRNA gene revealed that strain MPT belonged to the genus Thermococcus and it is proposed that this isolate should be designated as a new species, Thermococcus barophilus. Immunol Rev, 1999 Feb, 167, 211 - 21 The mouse major histocompatibility complex: some assembly required; Amadou C et al.; We have assembled a contig of 81 yeast artificial chromosome clones that spans 8 Mb and contains the entire major histocompatibility complex (Mhc) from mouse strain C57BL/6 (H2b), and we are in the process of assembling an Mhc contig of bacterial artificial chromosome (BAC) clones from strain 129 (H2bc), which differs from C57BL/6 in the H2-Q and H2-T regions . The current BAC contig extends from Tapasin to D17Leh89 with gaps in the class II, H2-Q, and distal H2-M regions . Only four BAC clones were required to link the class I genes of the H2-Q and H2-T regions, and no new class I gene was found in the previous gap . The proximal 1 Mb of the H2-M region has been analyzed in detail and is ready for sequencing; it includes 21 class I genes or fragments, at least 14 olfactory receptor-like genes, and a number of non-class I genes that clearly establish a conserved synteny with the class I regions of the human and rat Mhc. Proc Natl Acad Sci U S A, 1999 May 11, 96(10), 5832 - 7 poc1: an Arabidopsis mutant perturbed in phytochrome signaling because of a T DNA insertion in the promoter of PIF3, a gene encoding a phytochrome-interacting bHLH protein; Halliday KJ et al.; The phytochrome family of informational photoreceptors has a central role in regulating light-responsive gene expression, but the mechanism of intracellular signal transduction has remained elusive . In a genetic screen for T DNA-tagged Arabidopsis mutants affected in early signaling intermediates, we identified poc1 (photocurrent 1), which exhibits enhanced responsiveness to red light . This phenotype is absent in a phyB (phytochrome B) null mutant background, indicating that the poc1 mutation enhances phyB signal transduction . The T DNA insertion in poc1 was found to be located in the promoter region of PIF3, a gene encoding a basic helix-loop-helix protein . The mutant phenotype seems to result from insertion-induced overexpression of this gene in red-light-grown seedlings, consistent with PIF3 functioning as a positively acting signaling intermediate . These findings, combined with data from a separate yeast two-hybrid screen that identified PIF3 as a phytochrome-interacting factor necessary for normal signaling, provide evidence that phytochrome signal transduction may include a direct pathway to photoresponsive nuclear genes via physical interaction of the photoreceptor molecules with the potential transcriptional regulator PIF3. Proc Natl Acad Sci U S A, 1999 May 11, 96(10), 5528 - 32 Interaction of rat hormone-sensitive lipase with adipocyte lipid-binding protein; Shen WJ et al.; Hormone-sensitive lipase (HSL) is a cytosolic neutral lipase that functions as the rate-limiting enzyme for the mobilization of free fatty acids in adipose tissue . By using the yeast two-hybrid system to examine the potential interaction of HSL with other cellular proteins, evidence is provided to demonstrate a direct interaction of HSL with adipocyte lipid-binding protein (ALBP), a member of the family of intracellular lipid-binding proteins that binds fatty acids, retinoids, and other hydrophobic ligands . The interaction was demonstrated in vitro by the binding of ALBP to HSL translated in vitro, to HSL in extracts of HSL overexpressing Chinese hamster ovary (CHO) cells, and to HSL in extracts of rat adipose tissue . Finally, the presence of ALBP was documented in immune complexes from rat adipose tissue immunoprecipitated with anti-HSL antibodies . The HSL-ALBP interaction was mapped to an N-terminal 300-aa region of HSL that is distinct from the C-terminal catalytic domain . These results suggest that HSL-derived fatty acids are bound by ALBP to facilitate intracellular trafficking of hydrophobic lipids. J Biol Chem, 1999 May 14, 274(20), 14422 - 8 Myb-interacting protein, ATBF1, represses transcriptional activity of Myb oncoprotein; Kaspar P et al.; Using the yeast two-hybrid system, the transcription factor ATBF1 was identified as v-Myb- and c-Myb-binding protein . Deletion mutagenesis revealed amino acids 2484-2520 in human ATBF1 and 279-300 in v-Myb as regions required for in vitro binding of both proteins . Further experiments identified leucines Leu325 and Leu332 of the Myb leucine zipper motif as additional amino acid residues important for efficient ATBF1-Myb interaction in vitro . In co-transfection experiments, the full-length ATBF1 was found to form in vivo complexes with v-Myb and inhibit v-Myb transcriptional activity . Both ATBF1 2484-2520 and Myb 279-300 regions were required for the inhibitory effect . Finally, the chicken ATBF1 was identified, showing high degree of amino acid sequence homology with human and murine proteins . Our data reveal Myb proteins as the first ATBF1 partners detected so far and identify amino acids 279-300 in v-Myb as a novel protein-protein interaction interface through which Myb transcriptional activity can be regulated. J Biol Chem, 1999 May 14, 274(20), 14382 - 91 A protein phosphatase methylesterase (PME-1) is one of several novel proteins stably associating with two inactive mutants of protein phosphatase 2A; Ogris E et al.; Carboxymethylation of proteins is a highly conserved means of regulation in eukaryotic cells . The protein phosphatase 2A (PP2A) catalytic (C) subunit is reversibly methylated at its carboxyl terminus by specific methyltransferase and methylesterase enzymes which have been purified, but not cloned . Carboxymethylation affects PP2A activity and varies during the cell cycle . Here, we report that substitution of glutamine for either of two putative active site histidines in the PP2A C subunit results in inactivation of PP2A and formation of stable complexes between PP2A and several cellular proteins . One of these cellular proteins, herein named protein phosphatase methylesterase-1 (PME-1), was purified and microsequenced, and its cDNA was cloned . PME-1 is conserved from yeast to human and contains a motif found in lipases having a catalytic triad-activated serine as their active site nucleophile . Bacterially expressed PME-1 demethylated PP2A C subunit in vitro, and okadaic acid, a known inhibitor of the PP2A methylesterase, inhibited this reaction . To our knowledge, PME-1 represents the first mammalian protein methylesterase to be cloned . Several lines of evidence indicate that, although there appears to be a role for C subunit carboxyl-terminal amino acids in PME-1 binding, amino acids other than those at the extreme carboxyl terminus of the C subunit also play an important role in PME-1 binding to a catalytically inactive mutant. J Biol Chem, 1999 May 14, 274(20), 14331 - 6 Heterodimeric interactions between chicken ovalbumin upstream promoter-transcription factor family members ARP1 and ear2; Avram D et al.; Members of the chicken ovalbumin upstream promoter-transcription factor (COUP-TF) subfamily of orphan nuclear receptors, which minimally includes COUP-TFI and ARP1, are highly expressed in brain and are generally considered to be constitutive repressors of transcription . We have used a yeast two-hybrid system to isolate proteins expressed in brain that interact with ARP1 . One of the proteins isolated in this screen was Ear2, another orphan receptor that has been suggested to be a member of the COUP-TF subfamily . Here we demonstrate that ARP1 and Ear2 form heterodimers in solution and on directly repeated response elements with high efficiency and a specificity differing from that of homodimeric complexes composed of either receptor . ARP1 and Ear2 were observed to interact in mammalian cells, and the tissue distribution of Ear2 transcripts was found to overlap precisely with the expression pattern of ARP1 in several mouse tissues and embryonal carcinoma cell lines . Heterodimeric interactions between ARP1 and Ear2 may define a distinct pathway of orphan receptor signaling. Plant Physiol, 1999 May, 120(1), 23 - 32 Messenger RNA-binding properties of nonpolysomal ribonucleoproteins from heat-stressed tomato cells Stuger R, Ranostaj S, Materna T, Forreiter C. Most cells experiencing heat stress reprogram their translational machinery to favor the synthesis of heat-stress proteins . Translation of other transcripts is almost completely repressed, but most untranslated messengers are not degraded . In contrast to yeast, Drosophila melanogaster, and HeLa cells, plant cells store repressed messengers in cytoplasmic nonpolysomal ribonucleoproteins (RNPs) . To follow the fate of untranslated transcripts, we studied protein composition, mRNA content, and RNA-binding properties of nonpolysomal RNPs from heat-stressed tomato (Lycopersicon peruvianum) cells . Contrary to the selective interaction in vivo, RNPs isolated from tomato cells bound both stress-induced and repressed messengers, suggesting that the selection mechanism resides elsewhere . This binding was independent of a cap or a poly(A) tail . The possible role of proteasomes and heat-stress granules (HSGs) in mRNA storage is a topic of debate . We found in vitro messenger-RNA-binding activity in messenger RNP fractions free of C2-subunit-containing proteasomes and HSGs . In addition, mRNAs introduced into tobacco (Nicotiana plumbaginifolia) protoplasts were found in the cytoplasm but were not associated with HSGs. Plant Physiol, 1999 May, 120(1), 257 - 74 Two SNF1-related protein kinases from spinach leaf phosphorylate and inactivate 3-hydroxy-3-methylglutaryl-coenzyme A reductase, nitrate reductase, and sucrose phosphate synthase in vitro; Sugden C et al.; We resolved from spinach (Spinacia oleracea) leaf extracts four Ca2+-independent protein kinase activities that phosphorylate the AMARAASAAALARRR (AMARA) and HMRSAMSGLHLVKRR (SAMS) peptides, originally designed as specific substrates for mammalian AMP-activated protein kinase and its yeast homolog, SNF1 . The two major activities, HRK-A and HRK-C (3-hydroxy-3-methylglutaryl-coenzyme A reductase kinase A and C) were extensively purified and shown to be members of the plant SnRK1 (SNF1-related protein kinase 1) family using the following criteria: (a) They contain 58-kD polypeptides that cross-react with an antibody against a peptide sequence characteristic of the SnRK1 family; (b) they have similar native molecular masses and specificity for peptide substrates to mammalian AMP-activated protein kinase and the cauliflower homolog; (c) they are inactivated by homogeneous protein phosphatases and can be reactivated using the mammalian upstream kinase; and (d) they phosphorylate 3-hydroxy-3-methylglutaryl-coenzyme A reductase from Arabidopsis at the inactivating site, serine (Ser)-577 . We propose that HRK-A and HRK-C represent either distinct SnRK1 isoforms or the same catalytic subunit complexed with different regulatory subunits . Both kinases also rapidly phosphorylate nitrate reductase purified from spinach, which is associated with inactivation of the enzyme that is observed only in the presence of 14-3-3 protein, a characteristic of phosphorylation at Ser-543 . Both kinases also inactivate spinach sucrose phosphate synthase via phosphorylation at Ser-158 . The SNF1-related kinases therefore potentially regulate several major biosynthetic pathways in plants: isoprenoid synthesis, sucrose synthesis, and nitrogen assimilation for the synthesis of amino acids and nucleotides. Plant Physiol, 1999 May, 120(1), 53 - 64 Transformation of the collateral vascular bundles into amphivasal vascular bundles in an Arabidopsis mutant; Zhong R et al.; Arabidopsis inflorescence stems develop a vascular pattern similar to that found in most dicots . The arrangement of vascular tissues within the bundle is collateral, and vascular bundles in the stele are arranged in a ring . Although auxin has been shown to be an inducer of vascular differentiation, little is known about the molecular mechanisms controlling vascular pattern formation . By screening ethyl methanesufonate-mutagenized populations of Arabidopsis, we have isolated an avb1 (amphivasal vascular bundle) mutant with a novel vascular pattern . Unlike the collateral vascular bundles seen in the wild-type stems, the vascular bundles in the avb1 stems were similar to amphivasal bundles, i.e . the xylem completely surrounded the phloem . Furthermore, branching vascular bundles in the avb1 stems abnormally penetrated into the pith, which resulted in a disruption in the ring-like arrangement of vascular bundles in the stele . The avb1 mutation did not affect leaf venation pattern and root vascular organization . Auxin polar transport assay indicated that the avb1 mutation did not disrupt the auxin polar transport activity in inflorescence stems . The avb1 mutation also exhibited pleiotropic phenotypes, including curled stems and extra cauline branches . Genetic analysis indicated that the avb1 mutation was monogenic and partially dominant . The avb1 locus was mapped to a region between markers mi69 and ASB2, which is covered by a yeast artificial chromosome clone, CIC9E2, on chromosome 5 . Isolation of the avb1 mutant provides a novel means to study the evolutionary mechanisms controlling the arrangement of vascular tissues within the bundle, as well as the mechanisms controlling the arrangement of vascular bundles in the stele. J Oral Pathol Med, 1999 Apr, 28(4), 178 - 82 Paediatric AIDS--related linear gingival erythema: a form of erythematous candidiasis? Velegraki A, Nicolatou O, Theodoridou M, Mostrou G, Legakis NJ. Three vertically HIV-infected children showed, in addition to oral candidiasis, HIV-gingivitis, which healed on antimycotic treatment . The intense linear gingival erythema of a fourth child was also clinically evaluated as a possible form of erythematous oral candidiasis . Direct microscopic examination of material from the gingival lesions of the latter disclosed yeast cells and hyphae . Subsequent culture, biochemical and serological tests identified the yeast as Candida dubliniensis . As the patient was on long-term prophylaxis with fluconazole, ketoconazole was administered and led to a good clinical response . This is the first report implicating this new Candida species as a pathogen in linear gingival erythema in a HIV-positive individual . The case reports presented provide evidence that linear gingival erythema may be of candidal origin . Further clinical and laboratory observations are required to establish whether this condition constitutes a variant of erythematous candidiasis associated with paediatric HIV infection. Differentiation, 1999 Mar, 64(3), 161 - 71 Analysis of the pattern of QM expression during mouse development; Mills AA et al.; QM, a novel gene that was originally identified as a putative tumor suppressor gene, has since been cloned from species encompassing members of the plant, animal, and fungal kingdoms . Sequence comparison indicates that QM has been highly conserved throughout eukaryotic evolution . QM is a member of a multigene family in both mouse and man, is expressed in a broad range of tissues, and is downregulated during adipocyte differentiation . Jif-1, a chicken homolog of QM, has been reported to interact with the protooncogene c-Jun, and to inhibit transactivation of AP-1 regulated promoters in vitro . Furthermore, disruption of the yeast QM homolog is lethal . Although these studies suggest that the QM gene product plays an important role within the normal cell, the precise role of QM has remained elusive . In this study, a thorough analysis of the pattern of QM expression during mouse development was undertaken, using the techniques of whole mount in situ hybridization and whole mount immunohistochemistry, in combination with conventional immunohistochemical analysis of tissue sections . QM is expressed in numerous embryonic tissues, and is differentially expressed throughout the embryo . The cytoplasmic localization of QM is consistent with its reported association with ribosomes, and inconsistent with its previously hypothesized function as a direct modulator of the nuclear protooncogene c-Jun . QM is expressed in the developing epidermis, and is particularly strong within developing limbs . Analysis of embryos of various stages of gestation indicate that QM is downregulated in the surface ectoderm of the embryo as development proceeds . QM protein is not detectable within either nucleated or enucleated red blood cell precursors . QM is strongly expressed within chondrocytes within the transition zone of developing limb cartilage, as well as within differentiated keratinocytes of the suprabasal regions of the epidermis . Furthermore, within both cartilage and skin, there is an inverse relationship between QM expression and proliferative capacity . This pattern of QM expression suggests that this novel gene product may be involved in processes such as posttranslational protein processing which are essential for differentiation of specific tissues during embryogenesis. Eur J Hum Genet, 1999 Apr, 7(3), 332 - 8 Refinement of the RP17 locus for autosomal dominant retinitis pigmentosa, construction of a YAC contig and investigation of the candidate gene retinal fascin; Bardien-Kruger S et al.; The RP17 locus for autosomal dominant retinitis pigmentosa has previously been mapped to chromosome 17q by linkage analysis . Two unrelated South African families are linked to this locus and the identification of key recombination events assigned the RP17 locus to a 10 cM interval on 17q22 . The work reported here refines the mapping of the locus from a 10 cM to a 1 cM interval between the microsatellite markers D17S1604 and D17S948 . A physical map of this interval was constructed using information from the Whitehead/MIT YAC contig WC 17.8 . Sequence-tagged site (STS) content mapping of seven overlapping YACs from this contig was employed in order to build the map . A BAC library was screened to cover a gap in the YAC contig and two positive BACs were identified . Intragenic polymorphisms in the retinal fascin gene provided evidence for the exclusion of this candidate as the RP17 disease gene. Ann Transplant, 1998, 3(3), 21 - 4 Opportunistic fungal infections in patients treated with heart transplantation--own centre experiences; Konduracka E; The aim of this study was to analyse frequency, type and course of fungal infection in patients treated with heart transplantation (HT) and to estimate the efficacy of diagnostic procedures in patients before and after HT . The study was conducted on 30 patients (group I) aged 20-64 referred for HT and treated after HT in Coronary Disease Department in Cracow . Standard immunosuppressive protocol consisting of CSA-A, Aza, Prednisone was administered to all recipients after HT . As a control group 40 healthy persons aged 25-65 were examined . In all persons quantitative and mycoserological examinations were carried out according to a special protocol . In some justified cases despite serological and quantitative examinations, bronchoscopy with BAL, biopsy procedure, histological examination of tissue were performed in patients after HT . The commonest infections in patients after HT were oropharyngeal Candida infections . They mostly occurred in the first months after HT, and were observed in 67% of recipients . Besides, in two patients deep Aspergillus infections were documented . Quantitative mycological examinations were very useful in diagnosing early stages of superficial mycoses . In none of these patients before HT were permanent oropharyngeal yeast and Aspergillus colonizations observed . Diagnosis of deep Aspergillus mycoses was difficult . Even antigen detection did not allow for making definitive diagnosis, because antigen was found in some recipients without infections and in some healthy persons . Definitive diagnosis depended on histological and mycological examinations of tissue sections obtained by surgical procedure and in second case by autopsy. Nippon Ishinkin Gakkai Zasshi, 1999, 40(2), 99 - 102 Subcutaneous phaeohyphomycosis caused by Phaeoacremonium rubrigenum in an immunosuppressed patient; Matsui T et al.; BACKGROUND: Phaeohyphomycosis refers to infection by dematiaceous fungi with pigmented hyphae or yeast-like cells in the tissue . In humans, this disease is usually considered to be an opportunistic infection . The causal agents of phaeohyphomycosis include numerous species belonging to different genera and they are increasing as a result of the development of intensive medical therapy . OBSERVATION: We report the case of a 61-year-old Japanese female under corticosteroid treatment for malignant rheumatoid arthritis . An asymptomatic subcutaneous tumor developed on the back of her left foot . Histological examination of the excised material revealed mixed cell granuloma (H&E) and the presence of branched hyphal elements (periodic acid-Schiff) . A fungus grown in pure culture was identified as Phaeoacremonium rubrigenum . CONCLUSION: The hyphomycete genus, Phaeoacremonium, was proposed in 1996 by Crous et al . Three species belonging to this genus have been isolated from clinical specimens: P . inflatipes, from a human toenail, human synovial fluid and human mycetoma of the foot, P . parasiticum, from a subcutaneous lesion on a kidney transplant patient and several other sources, and P . rubrigenum, from a human patient with pneumonia . To our knowledge, however, this is the first report of phaeohyphomycosis caused by Phaeoacremonium rubrigenum. J Neurosci, 1999 May 15, 19(10), 3926 - 34 Postsynaptic density-93 interacts with the delta2 glutamate receptor subunit at parallel fiber synapses; Roche KW et al.; The glutamate receptor subunit delta2 has a unique distribution at the parallel fiber-Purkinje cell synapse of the cerebellum, which is developmentally regulated such that delta2 occurs at both parallel fiber synapses and climbing fiber synapses early in development but is restricted to parallel fiber synapses in adult animals . To identify proteins that might be involved in the trafficking or docking of delta2 receptors, we screened a yeast two-hybrid library with the cytosolic C terminus of delta2 and isolated a member of the postsynaptic density (PSD)-95 family of proteins, which are known to interact with the extreme C termini of NMDA receptors . We find that delta2 binds specifically to PSD-93, which is enriched in Purkinje cells . In addition, PSD-93 clusters delta2 when they are coexpressed in heterologous cells, and clustering is disrupted by point mutations of delta2 that disrupt the delta2-PSD-93 interaction . Ultrastructural localization of PSD-93 and delta2 shows they are colocalized at parallel fiber synapses; however, PSD-93 also is present at climbing fiber synapses of the adult rat, where delta2 is not found, indicating that the presence of PSD-93 alone is not sufficient for determining the synaptic expression of delta2. J Virol, 1999 Jun, 73(6), 5018 - 25 The carboxy-terminal acidic domain of Rift Valley Fever virus NSs protein is essential for the formation of filamentous structures but not for the nuclear localization of the protein; Yadani FZ et al.; The ambisense S segment of Rift Valley fever (RVF) virus (a phlebovirus in the Bunyaviridae family) codes for two proteins: the viral complementary-sense RNA for the N nucleoprotein and the genomic-sense RNA for the nonstructural protein NSs . Except for the fact that the NSs protein is phosphorylated and forms filamentous structures in the nuclei of infected cells (R . Swanepoel and N . K . Blackburn, J . Gen . Virol . 34:557-561, 1977), its role is poorly understood, especially since the replication cycle of all these viruses takes place in the cytoplasm . To investigate the mechanisms involved in filament formation, we expressed NSs in mammalian cells via a recombinant Semliki Forest virus and demonstrated that the protein alone was able to form structures similar to those observed in RVF virus-infected cells, indicating that the presence of other RVF virus proteins is not required for filament formation . The yeast two-hybrid system was used to show that the protein interacts with itself and to map the interacting domains . Various deletion and substitution mutants were constructed, and the mutant proteins were analyzed by immunoprecipitation, Western blotting and immunofluorescence . These experiments indicated that the 10 to 17 amino acids of the carboxy-terminal domain were involved in self-association of the protein and that deletion of this acidic carboxy-terminal domain prevents the protein from forming filaments but does not affect its nuclear localization . The role of two phosphorylation sites present in this domain was also investigated, but they were not found to have a major influence on the formation of the nuclear filament. J Invest Dermatol, 1999 May, 112(5), 751 - 6 UVB activates ERK1/2 and p38 signaling pathways via reactive oxygen species in cultured keratinocytes; Peus D et al.; We have previously shown that hydrogen peroxide is an important mediator of ultraviolet B induced phosphorylation of the epidermal growth factor receptor in human keratinocytes . Here we demonstrate that physiologic doses of ultraviolet B and hydrogen peroxide stimulate activation of two related but distinct mitogen-activated protein kinase pathways: extracellular regulated kinase 1 and 2 (ERK1/2), as well as p38, the mammalian homolog of HOG1 in yeast which is a major kinase for a recently identified stress-induced signaling pathway . The time-dependent activation of ERK1/2 and p38 are distinct, and ultraviolet B-induced ERK1/2 activation is downregulated more rapidly than p38 . Using dihydrorhodamine or Amplex as specific fluorescent dye probes, we show that ultraviolet B-induced peroxides can be inhibited by ascorbic acid . Ascorbic acid strongly blocks ERK1/2 and p38 activation by ultraviolet B and hydrogen peroxide whereas pyrrolidine dithiocarbamate and butyl hydroxyanisole are less effective . Pyrrolidine dithiocarbamate was unable to inhibit ultraviolet B-induced p38 activation . Cell death was increased after ultraviolet B when ERK1/2 activation was attenuated by the specific inhibitor PD098059 . The distinct time courses and extents of activation and inhibition of ERK1/2 and p38 indicate that these pathways are separate and regulated independently in keratinocytes . Specific types of reactive oxygen species induced by ultraviolet B as well as selective activation or inhibition of specific phosphatases may mediate these responses in keratinocytes . These findings demonstrate that reactive oxygen species are important multifunctional mediators of ultraviolet B-induced ERK1/2 and p38 signaling transduction pathways and suggest that ERK1/2 may play an important part in protecting keratinocytes from cell death following oxidative stress. Cancer Res, 1999 May 1, 59(9), 2041 - 4 Centrosomal kinase AIK1 is overexpressed in invasive ductal carcinoma of the breast; Tanaka T et al.; A centrosomal serine/threonine kinase, AIK1(3)/breast tumor amplified kinase/aurora2, which was recently identified as an oncogene, shows high amino acid identity with chromosome segregation kinases, fly Aurora, and yeast Ipl1 . Immunohistochemical analyses of invasive ductal adenocarcinomas of the breast revealed that overexpression of AIK1 was observed in 94% of the cases, irrespective of the histopathological type, whereas the protein was not detected in normal ductal and lobular cells . Benign breast lesions including fibrocystic disease and fibroadenoma (epithelial components) displayed weakly detectable AIK1 expression in part of the lesions . This is the first immunohistochemical report of AIK1 expression in primary human breast carcinomas . Although the physiological function(s) of AIK1 kinase during cell division remains to be determined, the markedly high positivity of AIK1 staining in the cancer lesions suggested a possible involvement of its overexpression in the tumorigenesis of some of breast cancer cells. Genome, 1999 Apr, 42(2), 330 - 7 Application of restriction fragment fingerprinting with a rice microsatellite sequence to assembling rice YAC clones; Ashikawa I et al.; To refine the current physical map of rice, we have established a restriction fragment fingerprinting method for identifying overlap between pairs of rice yeast artificial chromosome (YAC) clones and defining the physical arrangement of YACs within contiguous fragments (contigs) . In this method, Southern blots of rice YAC DNAs digested with a restriction endonuclease are probed with a rice microsatellite probe, (GGC)5 . The probe produces a unique fingerprint profile characteristic of each YAC clone . The profile is then digitized, processed in a computer, and a statistic that represents the degree of overlap between two YACs is calculated . The statistics have been used to detect overlaps among YAC clones, thereby filling a gap between two neighbouring contigs and organizing overlapping rice YAC clones into contiguous fragments . We applied this method to rearranging YACs that had previously been assigned to rice chromosome 6 by anchoring with RFLP markers. Gene, 1999 Apr 29, 231(1-2), 111 - 20 A compact gene cluster in Drosophila: the unrelated Cs gene is compressed between duplicated amd and Ddc; Tatarenkov A et al.; Cs, a gene with unknown function, and amd and Ddc, which encode decarboxylases, are among the most closely spaced genes in D . melanogaster . Untranslated 3' ends of the convergently transcribed genes Cs and Ddc are known to overlap by 88bp . A number of questions arise about the organization of this tightly-packed gene region and about the evolution and function of the Cs gene . We have now investigated this three-gene cluster in Scaptodrosophila lebanonensis (which diverged from D . melanogaster 60-65 MYA), as well as in D . melanogaster and D . simulans . Gene order and direction of transcription is the same in all three species . The Cs gene codes, in Scaptodrosophila, for a polypeptide of 544 amino acids; in D . melanogaster, it consists of 504 amino acids, which is twice as long as previously suggested, which makes the gene density even more spectacular . The Cs sequences exhibit higher number of non-synonymous substitutions between species, higher ratios of non-synonymous to synonymous substitutions, and lower codon usage bias than other genes, suggesting that Cs is less functionally constrained than the other genes . This is consistent with the failure of inducing phenotypic mutations in D . melanogaster . The function of Cs remains to be identified, but a high degree of similarity indicates that it is homologous to genes coding for a corticosteroid-binding protein in yeast and a polyamine oxidase in maize. Environ Health Perspect, 1999 Feb, 107 Suppl 1, 89 - 108 Comparison of short-term estrogenicity tests for identification of hormone-disrupting chemicals; Andersen HR et al.; The aim of this study was to compare results obtained by eight different short-term assays of estrogenlike actions of chemicals conducted in 10 different laboratories in five countries . Twenty chemicals were selected to represent direct-acting estrogens, compounds with estrogenic metabolites, estrogenic antagonists, and a known cytotoxic agent . Also included in the test panel were 17beta++-estradiol as a positive control and ethanol as solvent control . The test compounds were coded before distribution . Test methods included direct binding to the estrogen receptor (ER), proliferation of MCF-7 cells, transient reporter gene expression in MCF-7 cells, reporter gene expression in yeast strains stably transfected with the human ER and an estrogen-responsive reporter gene, and vitellogenin production in juvenile rainbow trout . 17beta-Estradiol, 17alpha-ethynyl estradiol, and diethylstilbestrol induced a strong estrogenic response in all test systems . Colchicine caused cytotoxicity only . Bisphenol A induced an estrogenic response in all assays . The results obtained for the remaining test compounds--tamoxifen, ICI 182.780, testosterone, bisphenol A dimethacrylate, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol dodecylethoxylate, butylbenzylphthalate, dibutylphthalate, methoxychlor, o,p'-DDT, p,p'-DDE, endosulfan, chlomequat chloride, and ethanol--varied among the assays . The results demonstrate that careful standardization is necessary to obtain a reasonable degree of reproducibility . Also, similar methods vary in their sensitivity to estrogenic compounds . Thus, short-term tests are useful for screening purposes, but the methods must be further validated by additional interlaboratory and interassay comparisons to document the reliability of the methods. Eur J Biochem, 1999 May, 262(1), 36 - 42 Structure and splice products of the human gene encoding sds22, a putative mitotic regulator of protein phosphatase-1; Ceulemans H et al.; sds22 is a regulatory subunit of protein phosphatase-1 that is required for the completion of mitosis in yeast . It consists largely of 11 tandem leucine-rich repeats of 22 residues that are expected to mediate interactions with other polypeptides, including protein phosphatase-1 . In this paper, we report on the structure of the human gene encoding sds22, designated PPP1R7 . This gene (33 kb) comprises 11 exons, but these do not coincide with the sequences encoding the leucine-rich repeats . Up to six splice variants can be generated by exon skipping and alternative polyadenylation, as revealed by expressed sequence tag database analysis, RT-PCR and Northern blot analysis . The sds22 transcripts are expected to encode four different polypeptides . sds22alpha1 corresponds to the variant cloned previously from human brain {Renouf et al . (1995) FEBS Lett . 375, 75-78} . Sds22beta1 is truncated within the ninth repeat and has a short and different C-terminus . Both variants also exist without the sequence corresponding to exon 2, and these are termed sds22alpha2 and sds22beta2 . The 5'-flanking region of PPP1R7 contains two NF-Y-binding CCAAT boxes near the transcription start site and potential binding sites for the transcription factors c-Myb, Ik-2 and NF-1, which are conserved in the mouse gene. DNA Res, 1999 Feb 26, 6(1), 37 - 44 Characterization of a 1200-kb genomic segment of chromosome 3p22-p21.3; Daigo Y et al.; We previously determined the nucleotide sequence and characterized the 685-kb proximal half of CEPH YAC936c1, which corresponds to a portion of human chromosome 3p21.3 . In the study reported here, we characterized the remaining 515-kb of this YAC clone corresponding to the telomeric half of its human insert . The newly sequenced region contained a total of ten genes including six reported previously: phospholipase C delta 1 (PLCD1), human activin receptor type IIB (hActR-IIB), organic cation transporter-like 1 (OCTL1), organic cation transporter-like 2 (OCTL2), oxidative stress response 1 (OSR1), and human xylulokinase-like protein (XYLB) . The remaining four genes present in the telomeric region included two known genes, MyD88 and ACAA, and two novel genes . One (designated ENGL) of the novel sequences was found to encode an amino-acid sequence homologous to the family of DNA/RNA endonucleases, especially endonuclease G . The other gene F56 revealed no significant homology to any known genes . These results disclosed complete physical and transcriptional maps of the 1200-kb region of 3p present in YAC 936c1. Neuron, 1999 Apr, 22(4), 809 - 18 A dynamically regulated 14-3-3, Slob, and Slowpoke potassium channel complex in Drosophila presynaptic nerve terminals; Zhou Y et al.; Slob is a novel protein that binds to the carboxy-terminal domain of the Drosophila Slowpoke (dSlo) calcium-dependent potassium (K(Ca)) channel . A yeast two-hybrid screen with Slob as bait identifies the zeta isoform of 14-3-3 as a Slob-binding protein . Coimmunoprecipitation experiments from Drosophila heads and transfected cells confirm that 14-3-3 interacts with dSlo via Slob . All three proteins are colocalized presynaptically at Drosophila neuromuscular junctions . Two serine residues in Slob are required for 14-3-3 binding, and the binding is dynamically regulated in Drosophila by calcium/calmodulin-dependent kinase II (CaMKII) phosphorylation . 14-3-3 coexpression dramatically alters dSlo channel properties when wild-type Slob is present but not when a double serine mutant Slob that is incapable of binding 14-3-3 is present . The results provide evidence for a dSlo/Slob/14-3-3 regulatory protein complex. Plant J, 1999 Mar, 17(6), 667 - 78 Inhibition of protoporphyrinogen oxidase expression in Arabidopsis causes a lesion-mimic phenotype that induces systemic acquired resistance; Molina A et al.; We have used an antisense expression technology in Arabidopsis based on the yeast GAL4/UAS transactivation system (Guyer et al., Genetics, 1998; 149:633-639) to reduce levels of protoporphyrinogen IX oxidase (PPO), the last common enzyme of the biosynthesis of the haem group and chlorophyll . Plants expressing the antisense PPO gene presented growth alterations and their leaves showed necrotic lesions that appeared similar to lesions characteristic of the pathogen-induced hypersensitive reaction, and seen in the so-called lesion-mimic mutants . Plants expressing the antisense gene also had high endogenous salicylic acid levels, constitutive expression of the PR-1 gene, and were resistant to Peronospora parasitica, consistent with the activation of systemic acquired resistance (SAR) . Treatment of wild-type plants with sublethal concentrations of herbicides that inhibit PPO also induced defence responses that conferred enhanced tolerance to P . parasitica . This effect was not observed in NahG and nim1 plants, which are compromised in their ability to activate SAR . These results demonstrate that genetic or chemical disruption of a metabolic pathway can lead to the induction of a set of defence responses including activation of SAR. Bioelectrochem Bioenerg, 1999 Feb, 48(1), 3 - 16 Fundamentals of electroporative delivery of drugs and genes; Neumann E et al.; Electrooptical and conductometrical relaxation methods have given a new insight in the molecular mechanisms of the electroporative delivery of drug-like dyes and genes (DNA) to cells and tissues . Key findings are: (1) Membrane electroporation (ME) and hence the electroporative transmembrane transport of macromolecules are facilitated by a higher curvature of the membrane as well as by a gradient of the ionic strength across charged membranes, affecting the spontaneous curvature . (2) The degree of pore formation as the primary field response increases continuously without a threshold field strength, whereas secondary phenomena, such as a dramatic increase in the membrane permeability to drug-like dyes and DNA (also called electropermeabilization), indicate threshold field strength ranges . (3) The transfer of DNA by ME requires surface adsorption and surface insertion of the permeant molecule or part of it . The diffusion coefficient for the translocation of DNA (M(r) approximately 3.5 x 10(6)) through the electroporated membrane is Dm = 6.7 x 10(-13) cm2 s-1 and Dm for the drug-like dye Serva Blue G (M(r) approximately 854) is Dm = 2.0 x 10(-12) cm2 s-1 . The slow electroporative transport of both DNA and drugs across the electroporated membrane reflects highly interactive (electro-) diffusion, involving many small pores coalesced into large, but transiently occluded pores (DNA) . The data on mouse B-cells and yeast cells provide directly the flow and permeability coefficients of Serva blue G and plasmid DNA at different electroporation protocols . The physico-chemical theory of ME and electroporative transport in terms of time-dependent flow coefficients has been developed to such a degree that analytical expressions are available to handle curvature and ionic strength effects on ME and transport . The theory presents further useful tools for the optimization of the ME techniques in biotechnology and medicine, in particular in the new field of electroporative delivery of drugs (electrochemotherapy) and of DNA transfer and gene therapy. EMBO J, 1999 May 4, 18(9), 2631 - 7 Structure and interactions of the translation initiation factor eIF1; Fletcher CM et al.; eIF1 is a universally conserved translation factor that is necessary for scanning and involved in initiation site selection . We have determined the solution structure of human eIF1 with an N-terminal His tag using NMR spectroscopy . Residues 29-113 of the native sequence form a tightly packed domain with two alpha-helices on one side of a five-stranded parallel and antiparallel beta-sheet . The fold is new but similar to that of several ribosomal proteins and RNA-binding domains . A likely binding site is indicated by yeast mutations and conserved residues located together on the surface . No interaction with recombinant eIF5 or the initiation site RNA GCCACAAUGGCA was detected by NMR, but GST pull-down experiments show that eIF1 binds specifically to the p110 subunit of eIF3 . This interaction explains how eIF1 is recruited to the 40S ribosomal subunit. Neurochem Res, 1999 Apr, 24(4), 565 - 80 Peroxisomal disorders: clinical, biochemical, and molecular aspects; Wanders RJ; Peroxisomes are subcellular organelles catalyzing a number of indispensable functions in cellular metabolism . The importance of peroxisomes in man is stressed by the existence of an expanding group of genetic diseases in which there is an impairment in one or more peroxisomal functions . Much has been learned in recent years about these functions and many of the enzymes involved have been characterized, purified and their cDNAs cloned . This has allowed resolution of the enzymatic and molecular basis of many of the single peroxisomal enzyme deficiencies . Similarly, the molecular basis of the peroxisome biogenesis disorders is also being resolved rapidly thanks to the successful use of CHO as well as yeast mutants . In this paper we will provide an overview of the peroxisomal disorders with particular emphasis on their clinical, biochemical and molecular characteristics. J Med Genet, 1999 Apr, 36(4), 271 - 8 Systematic characterisation of disease associated balanced chromosome rearrangements by FISH: cytogenetically and genetically anchored YACs identify microdeletions and candidate regions for mental retardation genes; Wirth J et al.; Disease associated balanced chromosome rearrangements (DBCRs) have been instrumental in the isolation of many disease genes . To facilitate the molecular cytogenetic characterisation of DBCRs, we have generated a set of >1200 non-chimeric, cytogenetically and genetically anchored CEPH YACs, on average one per 3 cM, spaced over the entire human genome . By fluorescence in situ hybridisation (FISH), we have performed a systematic search for YACs spanning translocation breakpoints . Patients with DBCRs and either syndromic or non-syndromic mental retardation (MR) were ascertained through the Mendelian Cytogenetics Network (MCN), a collaborative effort of, at present, 270 cytogenetic laboratories throughout the world . In this pilot study, we have characterised 10 different MR associated chromosome regions delineating candidate regions for MR . Five of these regions are narrowed to breakpoint spanning YACs, three of which are located on chromosomes 13q21, 13q22, and 13q32, respectively, one on chromosome 4p14, and one on 6q25 . In two out of six DBCRs, we found cytogenetically cryptic deletions of 3-5 Mb on one or both translocation chromosomes . Thus, cryptic deletions may be an important cause of disease in seemingly balanced chromosome rearrangements that are associated with a disease phenotype . Our region specific FISH probes, which are available to MCN members, can be a powerful tool in clinical cytogenetics and positional cloning. Fundam Clin Pharmacol, 1999, 13(2), 220 - 5 Effects of tramadol on experimental inflammation; Bianchi M et al.; We examined the ability of the analgesic drug tramadol to affect the development of inflammation in rats . The acute administration of tramadol significantly reduced the edema and the hyperalgesia induced by yeast injection in the paw . Moreover, in the subcutaneous carrageenin-induced inflammation, tramadol reduced the amount of the exudate, as well as the prostaglandin (PG)E2-like bio- and immuno-activity in the exudate; on the contrary, leukotriene (LT)B4 concentrations in the exudate were not changed . However, tramadol did not affect the ability of macrophages to migrate towards the chemotactic peptide N-formyl-L-methionil-L-leucyl-L-phenylalanine (FMLP) . Our results suggest that tramadol is able to inhibit the development of different types of inflammation in the rat without affecting immune mechanisms, and contribute to explain the efficacy of this drug in the treatment of inflammatory pain. Curr Biol, 1999 Apr 22, 9(8), 405 - 15 Rho-family GTPases require the Arp2/3 complex to stimulate actin polymerization in Acanthamoeba extracts; Mullins RD et al.; BACKGROUND: Actin filaments polymerize in vivo primarily from their fast-growing barbed ends . In cells and extracts, GTPgammaS and Rho-family GTPases, including Cdc42, stimulate barbed-end actin polymerization; however, the mechanism responsible for the initiation of polymerization is unknown . There are three formal possibilities for how free barbed ends may be generated in response to cellular signals: uncapping of existing filaments; severing of existing filaments; or de novo nucleation . The Arp2/3 complex localizes to regions of dynamic actin polymerization, including the leading edges of motile cells and motile actin patches in yeast, and in vitro it nucleates the formation of actin filaments with free barbed ends . Here, we investigated actin polymerization in soluble extracts of Acanthamoeba . RESULTS: Addition of actin filaments with free barbed ends to Acanthamoeba extracts is sufficient to induce polymerization of endogenous actin . Addition of activated Cdc42 or activation of Rho-family GTPases in these extracts by the non-hydrolyzable GTP analog GTPgammaS stimulated barbed-end polymerization, whereas immunodepletion of Arp2 or sequestration of Arp2 using solution-binding antibodies blocked Rho-family GTPase-induced actin polymerization . CONCLUSIONS: For this system, we conclude that the accessibility of free barbed ends regulates actin polymerization, that Rho-family GTPases stimulate polymerization catalytically by de novo nucleation of free barbed ends and that the primary nucleation factor in this pathway is the Arp2/3 complex. J Cell Biol, 1999 May 3, 145(3), 425 - 35 The maize homologue of the cell cycle checkpoint protein MAD2 reveals kinetochore substructure and contrasting mitotic and meiotic localization patterns; Yu HG et al.; We have identified a maize homologue of yeast MAD2, an essential component in the spindle checkpoint pathway that ensures metaphase is complete before anaphase begins . Combined immunolocalization of MAD2 and a recently cloned maize CENPC homologue indicates that MAD2 localizes to an outer domain of the prometaphase kinetochore . MAD2 staining was primarily observed on mitotic kinetochores that lacked attached microtubules; i.e., at prometaphase or when the microtubules were depolymerized with oryzalin . In contrast, the loss of MAD2 staining in meiosis was not correlated with initial microtubule attachment but was correlated with a measure of tension: the distance between homologous or sister kinetochores (in meiosis I and II, respectively) . Further, the tension-sensitive 3F3/2 phosphoepitope colocalized, and was lost concomitantly, with MAD2 staining at the meiotic kinetochore . The mechanism of spindle assembly (discussed here with respect to maize mitosis and meiosis) is likely to affect the relative contributions of attachment and tension . We support the idea that MAD2 is attachment-sensitive and that tension stabilizes microtubule attachments. Radiother Oncol, 1999 Jan, 50(1), 1 - 11 Towards prediction and modulation of treatment response; Bartelink H et al.; The purpose of this paper is to evaluate new predictive assays and their potential to modulate treatment response . Their impact is presented in the context of three EORTC clinical trials in head and neck, lung and breast cancer, showing an improvement in survival by accelerated fractionation, concomitant use of cisplatin and radiotherapy and adjuvant hormonal treatment, respectively . Assays have been developed to predict the response to treatment by measuring tumor characteristics, such as the growth potential by the labeling index after i.v . injection of IdUrd, the extent of radiation-induced stable and unstable chromosome aberrations and the induction of apoptosis . These assays could guide us in the adaptation of the individual radiation doses and fractionation schedules . The measurement of the effect of cisplatin on DNA has become feasible with the development of antibodies against DNA adducts . In a recently completed phase II dose escalation trial with concomitant radiotherapy and daily cisplatin in lung cancer, we found that patients with high DNA adduct levels measured in the buccal mucosa, had a much better survival rate than patients with a low or undetectable amount of cisplatin DNA adducts . A better understanding of the signal transduction pathways involved in radiation-induced apoptosis may help to design studies aimed at modulating the apoptotic response . We and others have recently shown that alkylphospholipids, which inhibit mitogenic signaling, induce apoptosis in a variety of tumor cell lines . In combination with ionizing radiation, these compounds cause an enhancement of apoptotic cell kill . This type of signaling-based intervention study may form the basis for new therapeutic strategies . Pretreatment levels of apoptosis may be helpful in predicting treatment outcome, although the data so far show inconsistent results . The importance of evaluating other tumor-biological parameters, including cell kinetics should be stressed . Based on assays predicting reliably the response to hormonal therapy, a more appropriate choice can be made for therapeutic intervention with hormonal therapy and for selecting the appropriate adjuvant therapy in breast cancer patients . The development of a functional estrogen receptor assay (ER-FASAY), based on a yeast growth-assay, provides a way of estimating abnormal function of the receptor in tumors with a positive estrogen receptor score as measured by a classical immuno-histochemistry assay . This yeast assay can also detect different DNA mutations of the estrogen receptor existing in an individual tumor specimen. Genetics, 1999 May, 152(1), 191 - 9 The pro1(+) gene from Sordaria macrospora encodes a C6 zinc finger transcription factor required for fruiting body development; Masloff S et al.; During sexual morphogenesis, the filamentous ascomycete Sordaria macrospora differentiates into multicellular fruiting bodies called perithecia . Previously it has been shown that this developmental process is under polygenic control . To further understand the molecular mechanisms involved in fruiting body formation, we generated the protoperithecia forming mutant pro1, in which the normal development of protoperithecia into perithecia has been disrupted . We succeeded in isolating a cosmid clone from an indexed cosmid library, which was able to complement the pro1(-) mutation . Deletion analysis, followed by DNA sequencing, subsequently demonstrated that fertility was restored to the pro1 mutant by an open reading frame encoding a 689-amino-acid polypeptide, which we named PRO1 . A region from this polypeptide shares significant homology with the DNA-binding domains found in fungal C6 zinc finger transcription factors, such as the GAL4 protein from yeast . However, other typical regions of C6 zinc finger proteins, such as dimerization elements, are absent in PRO1 . The involvement of the pro1(+) gene in fruiting body development was further confirmed by trying to complement the mutant phenotype with in vitro mutagenized and truncated versions of the pro1 open reading frame . Southern hybridization experiments also indicated that pro1(+) homologues are present in other sexually propagating filamentous ascomycetes. Appl Environ Microbiol, 1999 May, 65(5), 2179 - 83 Localized, positive charge mediates adhesion of rhodosporidium toruloides to barley leaves and polystyrene Buck JW, Andrews JH. The physicochemical forces that mediate attachment of yeasts to the phylloplane are unknown . Cell surface charge and hydrophobicity and adhesion to polystyrene, glass, and barley were assessed for wild-type Rhodosporidium toruloides and attachment-minus (Att-) mutants . Cells were grown under conditions promoting (excess carbon) or not promoting (excess nitrogen) capsule production . Hydrophobicity was measured by adhesion to xylenes, and surface charge characteristics were assessed by attachment to either DEAE (positive)- or carboxymethyl (CM) (negative)-Sephadex ion-exchange beads . Hydrophobicity and adhesiveness of nonencapsulated, wild-type R . toruloides decreased from mid-log to late stationary phase . Encapsulated wild-type R . toruloides cells were more hydrophobic and more adhesive than nonencapsulated cells . However, two encapsulated Att- mutants were more hydrophobic than the wild type and levels of adhesion of R . toruloides were similar on polystyrene and less hydrophobic glass surfaces . Adhesion of wild-type yeast to barley and polystyrene was correlated with attachment to CM-Sephadex beads, indicating a positive cell surface charge . Sixteen Att- mutants did not exhibit a positive cell surface charge, and wild-type yeast cells that did not attach to CM-Sephadex did not adhere to either polystyrene or barley . Wild-type R . toruloides attached to CM-Sephadex beads by the poles of the cells, indicating a localization of positive charge which was also visualized with India ink . We conclude that localized, positive charge, and not hydrophobic interactions, mediates attachment of R . toruloides to barley leaves. J Biol Chem, 1999 May 7, 274(19), 13711 - 7 Smad1 interacts with homeobox DNA-binding proteins in bone morphogenetic protein signaling; Shi X et al.; Bone morphogenetic proteins (BMP) transduce their signals into the cell through a family of mediator proteins known as Smads . Upon phosphorylation by the BMP receptors, Smad1 interacts with Smad4 and translocates into the nucleus where the complex recruits DNA-binding protein(s) to activate specific gene transcription . However, the DNA-binding protein(s) involved in BMP signaling has not been identified . Using a yeast two-hybrid approach, we found that Smad1 interacts with Hoxc-8, a homeodomain transcription factor . The interaction between Smad1 and Hoxc-8 was confirmed by a "pull-down" assay and a co-immunoprecipitation experiment in COS-1 cells . Interestingly, purified Smad1 inhibited Hoxc-8 binding to the osteopontin Hoxc-8 site in a concentration-dependent manner . Transient transfection studies showed that native osteopontin promoter activity was elevated upon BMP stimulation . Consistent with the gel shift assay, overexpression of Hoxc-8 abolished the BMP stimulation . When a wild type or mutant Hoxc-8 binding element was linked to an SV40 promoter-driven reporter gene, the wild type but not the mutant Hoxc-8 binding site responded to BMP stimulation . Again, overexpression of Hoxc-8 suppressed the BMP-induced activity of the wild type reporter construct . Our findings suggest that Smad1 interaction with Hoxc-8 dislodges Hoxc-8 from its DNA binding element, resulting in the induction of gene expression. J Biol Chem, 1999 May 7, 274(19), 12975 - 8 Loss-of-function and dominant-negative mechanisms associated with hepatocyte nuclear factor-1beta mutations in familial type 2 diabetes mellitus; Tomura H et al.; Hepatocyte nuclear factor (HNF)-1beta, a homeodomain-containing transcription factor, regulates gene expression in a dimerized form in pancreas, liver, and some other tissues . Recent genetic studies have identified two HNF-1beta mutations, R177X and A263fsinsGG, in subjects with a monogenic form of type 2 diabetes . Despite the defects being in the same gene, diverse severities of disease are observed in the affected subjects . To investigate the molecular mechanism by which mutations might cause various phenotypic features, wild type and mutant proteins were transiently expressed in insulin-producing (MIN6) and hepatic (HepG2) cells . Luciferase reporter assay showed that both mutations resulted in a marked reduction of transactivation activity . Because their dimerization activity was found to be intact by the yeast two-hybrid system, it was possible that they were dominant-negative to wild type activity . When co-expressed with wild type, both of the mutants significantly decreased wild type activity in HepG2 cells . In contrast, although A263fsinsGG functioned similarly in MIN6 cells, R177X failed to affect wild type activity in this cell line . Immunohistochemical analysis of the mutants suggests that this functional divergence might be generated by the modification of nuclear localization . These results suggest that HNF-1beta mutations may impair pancreatic beta-cell function by loss-of-function and dominant-negative mechanisms. Nippon Rinsho, 1999 Apr, 57(4), 856 - 61 {Cloning and characterization of cDNA for DRPLA interacting protein}; Okamumoho Y et al.; Dentatorubral-pallidoluysian atrophy (DRPLA) is associated with CAG repeat expansion . While the DRPLA gene is ubiquitously expressed, neuron death occurs in specific area of the brain, predicting that the DRPLA protein interacts with other proteins, which may play a role in the pathogenesis . We isolated a DRPLA binding protein with a yeast two-hybrid system, and identified it to be a human homologue of insulin receptor substrate protein of 53 kDa (IRSp53) . The binding of the DRPLA protein with IRSp53 was ascertained by co-immunoprecipitation, and colocalization . A proline-rich region near polyglutamine of the DRPLA protein and the SH3 domain of IRSp53 were involved in the binding . Extended polyglutamine significantly reduced the binding ability in yeast cells. Biochem Biophys Res Commun, 1999 Apr 29, 258(1), 102 - 8 Dynamics of DNA molecules in gel studied by fluorescence microscopy; Kantor RM et al.; The dynamics of individual DNA molecules in a thin gel were studied with fluorescence microscopy . Driven by an electric field, molecules hooked around isolated obstacles and became extended . By analyzing molecular images, we identified the reptation tube and primitive chain . When the field was turned off, the molecules relaxed . The relaxation time tau1 and primitive chain length <L> at equilibrium depend on N, the size of the molecule in base pairs, consistently with reptation theory . Using five yeast chromosomal DNAs ranging in size from 245 kb to 980 kb, we found that: These results constitute a way of sizing individual DNA molecules by imaging rather than by gel electrophoresis . Exp Cell Res, 1999 May 1, 248(2), 339 - 49 Subunits and substrates of the anaphase-promoting complex; Peters JM; The initiation of anaphase and exit from mitosis depend on a ubiquitination complex called the anaphase-promoting complex (APC) or cyclosome . The APC is composed of more than 10 constitutive subunits and associates with additional regulatory factors in mitosis and during the G1 phase of the cell cycle . At the metaphase-anaphase transition the APC ubiquitinates proteins such as Pds1 in budding yeast and Cut2 in fission yeast whose subsequent degradation by the 26S proteasome is essential for the initiation of sister chromatid separation . Later in anaphase and telophase the APC promotes the inactivation of the mitotic cyclin-dependent protein kinase 1 by ubiquitinating its activating subunit cyclin B . The APC also mediates the ubiquitin-dependent proteolysis of several other mitotic regulators, including other protein kinases, APC activators, spindle-associated proteins, and inhibitors of DNA replication . Genes Chromosomes Cancer, 1999 May, 25(1), 60 - 4 Identification of three commonly deleted regions on chromosome arm 6q in human pancreatic cancer; Abe T et al.; Pancreatic cancer has one of the poorest prognoses among malignant diseases . To understand its molecular mechanisms, we studied allelic losses on the long arm of chromosome 6 . Using 55 paired DNAs of tumors and their corresponding normal tissues and 30 microsatellite markers that spanned the entire 6q chromosome arm, we found three distinct regions of common allelic loss: region A, a less than 500-kb region bordered by D6S449 and D6S283 on 6q21 with a loss of heterozygosity (LOH) frequency of 69% (38/55); region B, a 7-cM region bordered by D6S292 and D6S308 on 6q23-q24 with a LOH frequency of 60% (33/55); and region C, a 13-cM region bordered by D6S305 and D6S264 with a LOH frequency of 51% (28/55) . We further focused on region A and constructed a physical map using yeast artificial chromosome (YAC) clones, their derived cosmid clones, and bacterial artificial chromosome (BAC) clones . Region A was completely covered by three overlapping BAC clones . Our results in the present study should shed light on the cloning and characterization of tumor suppressor genes in pancreatic carcinogenesis. Physiol Rev, 1999 Apr, 79(2), 361 - 85 Vacuolar and plasma membrane proton-adenosinetriphosphatases; Nelson N et al.; The vacuolar H+-ATPase (V-ATPase) is one of the most fundamental enzymes in nature . It functions in almost every eukaryotic cell and energizes a wide variety of organelles and membranes . V-ATPases have similar structure and mechanism of action with F-ATPase and several of their subunits evolved from common ancestors . In eukaryotic cells, F-ATPases are confined to the semi-autonomous organelles, chloroplasts, and mitochondria, which contain their own genes that encode some of the F-ATPase subunits . In contrast to F-ATPases, whose primary function in eukaryotic cells is to form ATP at the expense of the proton-motive force (pmf), V-ATPases function exclusively as ATP-dependent proton pumps . The pmf generated by V-ATPases in organelles and membranes of eukaryotic cells is utilized as a driving force for numerous secondary transport processes . The mechanistic and structural relations between the two enzymes prompted us to suggest similar functional units in V-ATPase as was proposed to F-ATPase and to assign some of the V-ATPase subunit to one of four parts of a mechanochemical machine: a catalytic unit, a shaft, a hook, and a proton turbine . It was the yeast genetics that allowed the identification of special properties of individual subunits and the discovery of factors that are involved in the enzyme biogenesis and assembly . The V-ATPases play a major role as energizers of animal plasma membranes, especially apical plasma membranes of epithelial cells . This role was first recognized in plasma membranes of lepidopteran midgut and vertebrate kidney . The list of animals with plasma membranes that are energized by V-ATPases now includes members of most, if not all, animal phyla . This includes the classical Na+ absorption by frog skin, male fertility through acidification of the sperm acrosome and the male reproductive tract, bone resorption by mammalian osteoclasts, and regulation of eye pressure . V-ATPase may function in Na+ uptake by trout gills and energizes water secretion by contractile vacuoles in Dictyostelium . V-ATPase was first detected in organelles connected with the vacuolar system . It is the main if not the only primary energy source for numerous transport systems in these organelles . The driving force for the accumulation of neurotransmitters into synaptic vesicles is pmf generated by V-ATPase . The acidification of lysosomes, which are required for the proper function of most of their enzymes, is provided by V-ATPase . The enzyme is also vital for the proper function of endosomes and the Golgi apparatus . In contrast to yeast vacuoles that maintain an internal pH of approximately 5.5, it is believed that the vacuoles of lemon fruit may have a pH as low as 2 . Similarly, some brown and red alga maintain internal pH as low as 0.1 in their vacuoles . One of the outstanding questions in the field is how such a conserved enzyme as the V-ATPase can fulfill such diverse functions. FEMS Microbiol Lett, 1999 Apr 1, 173(1), 117 - 25 A mitogen-activated protein kinase (MPKA) is involved in polarized growth in the filamentous fungus, Aspergillus nidulans; Bussink HJ et al.; An Aspergillus nidulans kinase gene, which encodes a protein kinase with high similarity to mitogen-activated protein kinases involved in cell wall construction and morphogenesis in yeast species, was cloned and sequenced . Targeted deletion of the Aspergillus nidulans kinase gene indicates that this kinase is involved in germination of conidial spores and polarized growth . These defects were largely remedied on complex high osmolarity media, although abnormal swellings of hyphal tips were still observed . Glycerol (1 M) only supported the growth of compact colonies . The Aspergillus nidulans kinase gene is, thus, required for normal polarized growth at several stages of colony formation in the filamentous fungus A . nidulans. Proc Natl Acad Sci U S A, 1999 Apr 27, 96(9), 5322 - 7 Regulatory interaction of PRL1 WD protein with Arabidopsis SNF1-like protein kinases; Bhalerao RP et al.; Mutation of the PRL1 gene, encoding a regulatory WD protein, results in glucose hypersensitivity and derepression of glucose-regulated genes in Arabidopsis . The yeast SNF1 protein kinase, a key regulator of glucose signaling, and Arabidopsis SNF1 homologs AKIN10 and AKIN11, which can complement the Deltasnf1 mutation, were found to interact with an N-terminal domain of the PRL1 protein in the two-hybrid system and in vitro . AKIN10 and AKIN11 suppress the yeast Deltasnf4 mutation and interact with the SNF4p-activating subunit of SNF1 . PRL1 and SNF4 bind independently to adjacent C-terminal domains of AKIN10 and AKIN11, and these protein interactions are negatively regulated by glucose in yeast . AKIN10 and AKIN11, purified in fusion with glutathione S-transferase, undergo autophosphorylation and phosphorylate a peptide of sucrose phosphate synthase in vitro . The sucrose phosphate synthase-peptide kinase activity of AKIN complexes detected by immunoprecipitation is stimulated by sucrose in light-grown Arabidopsis plants . In comparison with wild type, the activation level of AKIN immunocomplexes is higher in the prl1 mutant, suggesting that PRL1 is a negative regulator of Arabidopsis SNF1 homologs . This conclusion is supported by the observation that PRL1 is an inhibitor of AKIN10 and AKIN11 in vitro. Chromosome Res, 1999, 7(1), 65 - 9 Characterization of an alphoid subfamily located near p-arm sequences on human chromosome 22; Eisenbarth I et al.; The centromeric heterochromatin of all human chromosomes is composed of tandemly repeated alpha satellite DNA . Here we describe another alphoid subfamily that maps to human chromosome 22 as determined by FISH . The alphoid sequences were isolated from three YAC-clones carrying DNA from the pericentromeric region of the short arm of human chromosome 22 and limited amounts of alphoid DNA . This property enabled us to map the members of the subfamily to the border of the centromeric region and the short arm of the chromosome . The new alphoid subfamily may contribute to the closure of the gap remaining between the centromeric and short-arm maps of human chromosome 22. FEBS Lett, 1999 Mar 19, 447(1), 76 - 80 Eos: a novel member of the Ikaros gene family expressed predominantly in the developing nervous system; Honma Y et al.; We identified a novel member of the Ikaros gene family, which has critical roles in the development of lymphoid lineages . This gene, which we named Eos, was expressed predominantly in the developing central and peripheral nervous system . Eos protein could interact with itself and Ikaros protein through its C-terminal portion in the yeast two hybrid assay . These findings suggested that Eos may have important roles in neural development similarly to the Ikaros family in the development of hemolymphoid tissue. Trends Genet, 1999 Apr, 15(4), 141 - 5 Non-conventional infectious elements in filamentous fungi; Silar P et al.; Old data (most often in French) described phenomena involving non-conventional infectious factors in filamentous fungi . Recently, it was shown that two yeast cytoplasmic determinants are similar to known mammalian prions, in that their different states are attributed to conformational changes of normal cellular proteins . In the light of this discovery, fungal elements are now being reconsidered . This review presents four elements that affect vegetative incompatibility, conidiogenesis, morphology and cell growth . Recently, one element has been shown to be a prion analogue . The status of the others is not clear . We consider the view that non-conventional inheritance might be initiated by the appearance, in the cytoplasm, of a metabolite or a macromolecule whose production involves a positive regulatory loop. Int J Biochem Cell Biol, 1999 Jan, 31(1), 37 - 41 Protein synthesis initiation factor 4G; Keiper BD et al.; eIF4G is a member of the class of translational initiation factors involved in mRNA recruitment to the 43S initiation complex . The proteins from yeast to mammals are present in multiple isoforms of 82-176 kDa . Mammalian eIF4G-1 is synthesized by internal initiation of translation and is specifically degraded by viral and host proteases activated by stress conditions . The role of eIF4G in protein synthesis is inferred from the presence of binding sites for other initiation factors that serve to co-localize the 5'- and 3'-termini of mRNA with RNA-helicase activity and the 40S ribosomal subunit . Growth-regulated mRNAs are preferentially translated under conditions of accentuated eIF4E-eIF4G interaction . Proteolysis of eIF4G or expression of competitor proteins interferes with its binding to either the 5'- or 3'-termini, changing the spectrum of mRNAs translated . Elevated eIF4G levels correlate with malignant cell transformation and diminished eIF4G levels, with nutritional deprivation and anoxia. Eur J Biochem, 1999 Apr, 261(2), 379 - 91 The structural and functional role of lysine residues in the binding domain of cytochrome c in the electron transfer to cytochrome c oxidase; Dopner S et al.; The interactions of yeast iso-1 cytochrome c with bovine cytochrome c oxidase were studied using cytochrome c variants in which lysines of the binding domain were substituted by alanines . Resonance Raman spectra of the fully oxidized complexes of both proteins reveal structural changes of both the heme c and the hemes a and a3 . The structural changes in cytochrome c are the same as those observed upon binding to phospholipid vesicles where the bound protein exists in two conformers, B1 and B2 . Whereas the structure of B1 is the same as that of the unbound cytochrome c, the formation of B2 is associated with substantial alterations of the heme pocket . In cytochrome c oxidase, the structural changes in both hemes refer to more subtle perturbations of the immediate protein environment and may be a result of a conformational equilibrium involving two states . These changes are qualitatively different to those observed for cytochrome c oxidase upon poly-l-lysine binding . The resonance Raman spectra of the various cytochrome c/cytochrome c oxidase complexes were analyzed quantitatively . The spectroscopic studies were paralleled by steady-state kinetic measurements of the same protein combinations . The results of the spectra analysis and the kinetic studies were used to determine the stability of the complexes and the conformational equilibria B2/B1 for all cytochrome c variants . The complex stability decreases in the order: wild-type WT > J72K > K79A > K73A > K87A > J72A > K86A > K73A/K79A (where J is the natural trimethyl lysine) . This order is not exhibited by the conformational equilibria . The electrostatic control of state B2 formation does not depend on individual intermolecular salt bridges, but on the charge distribution in a specific region of the front surface of cytochrome c that is defined by the lysyl residues at positions 72, 73 and 79 . On the other hand, the conformational changes in cytochrome c oxidase were found to be independent of the identity of the bound cytochrome c variant . The maximum rate constants determined from steady-state kinetic measurements could be related to the conformational equilibria of the bound cytochrome c using a simple model that assumes that the conformational transitions are faster than product formation . Within this model, the data analysis leads to the conclusion that the interprotein electron transfer rate constant is around two times higher in state B2 than in B1 . These results can be interpreted in terms of an increase of the driving force in state B2 as a result of the large negative shift of the reduction potential. Genes Dev, 1999 Apr 15, 13(8), 954 - 65 ebi regulates epidermal growth factor receptor signaling pathways in Drosophila; Dong X et al.; ebi regulates the epidermal growth factor receptor (EGFR) signaling pathway at multiple steps in Drosophila development . Mutations in ebi and Egfr lead to similar phenotypes and show genetic interactions . However, ebi does not show genetic interactions with other RTKs (e.g., torso) or with components of the canonical Ras/MAP kinase pathway . ebi encodes an evolutionarily conserved protein with a unique amino terminus, distantly related to F-box sequences, and six tandemly arranged carboxy-terminal WD40 repeats . The existence of closely related proteins in yeast, plants, and humans suggests that ebi functions in a highly conserved biochemical pathway . Proteins with related structures regulate protein degradation . Similarly, in the developing eye, ebi promotes EGFR-dependent down-regulation of Tramtrack88, an antagonist of neuronal development. Prog Neurobiol, 1999 Apr, 57(5), 507 - 25 Subcellular RNA compartmentalization; Mohr E; The phenomenon of mRNA sorting to defined subcellular domains is observed in diverse organisms such as yeast and man . It is now becoming increasingly clear that specific transport of mRNAs to extrasomal locations in nerve cells of the central and peripheral nervous system may play an important role in nerve cell development and synaptic plasticity . Although the majority of mRNAs that are expressed in a given neuron are confined to the cell somata, some transcript species are specifically delivered to dendrites and/or, albeit less frequently, to the axonal domain . The physiological role and the molecular mechanisms of mRNA compartmentalization is now being investigated extensively . Even though most of the fundamental aspects await to be fully characterized, a few interesting data are emerging . In particular, there are a number of different subcellular distribution patterns of different RNA species in a given neuronal cell type and RNA compartmentalization may differ depending on the electrical activity of nerve cells . Furthermore, RNA transport is different in neurons of different developmental stages . Considerable evidence is now accumulating that mRNA sorting, at least to dendrites and the initial axonal segment, enables local synthesis of key proteins that are detrimental for synaptic function, nerve cell development and the establishment and maintenance of nerve cell polarity . The molecular determinants specifying mRNA compartmentalization to defined microdomains of nerve cells are just beginning to be unravelled . Targeting appears to be determined by sequence elements residing in the mRNA molecule to which proteins bind in a manner to direct these transcripts along cytoskeletal components to their site of function where they may be anchored to await transcriptional activation upon demand. Mol Biochem Parasitol, 1999 Mar 15, 99(1), 11 - 9 Molecular cloning and nuclear localization of a histone deacetylase homologue in Plasmodium falciparum; Joshi MB et al.; Reversible acetylation of core histones plays an important role in transcriptional regulation, cell cycle progression and developmental events . The acetylation state of histones is controlled by a dynamic equilibrium between activities of histone acetylase and deacetylase enzymes . Histone deacetylase (HDAC) was recently suggested to be the target of a fungus-derived antiprotozoal agent exhibiting structural similarity to known HDAC inhibitors . We have initiated a study of HDAC of human malaria parasite, Plasmodium falciparum, to evaluate its potential as the target for novel antimalarials and its role in parasite development . We have isolated HDAC1 gene from the P . falciparum genomic and cDNA libraries . The nucleotide sequence contains no intervening sequence and its open reading frame (ORF) codes for a protein of 449 amino acid residues . We have named the protein, PfHDAC1, as the sequence shows significant homology to yeast, human and other eukaryotic HDACs . Northern blot analysis of the total RNA from different asexual and sexual stages of the parasite reveals the presence of single mRNA transcript, which is predominantly expressed in mature asexual blood stages and in gametocytes . Antiserum raised against a carboxyl terminal peptide immunoprecipitated an in vitro translated P . falciparum HDAC gene product and recognized an approximately 50 kDa protein in the Triton X-100 insoluble fraction of parasites . Immunoelectron microscopy analysis showed majority of the protein localized in the nucleus of P . falciparum . To our knowledge, this is the first HDAC gene isolated from the malaria parasite. Planta, 1999 Mar, 208(1), 125 - 31 Isolation and characterization of four type-1 ribosome-inactivating proteins, with polynucleotide:adenosine glycosidase activity, from leaves of Phytolacca dioica L; Di Maro A et al.; Four type-1 (single-chain) ribosome-inactivating proteins (RIPs), with isoelectric points between 9.5 and 9.7, were isolated from leaves of Phytolacca dioica L . The purification procedure furnished the four proteins with an overall yield of about 16% and separated them from a protein of 29,407 +/- 2 Da, as determined by electrospray mass spectrometry, whose N-terminal amino acid sequence differed from that of pokeweed (Phytolacca americana L.) leaf chitinase (PLC-B) by only one amino acid (R17I) . The four RIPs (PD-L1 to PD-L4) inhibited protein synthesis by a rabbit reticulocyte lysate with 50% inhibition at the picomolar level, and produced the beta-fragment, diagnostic of the specific enzymatic action of RIPs, on yeast ribosomes . Comparison of their N-terminal sequences, up to residue 45, showed that PD-L1 is identical to PD-L2 {designated the isoleucine (Ile) form from the N-terminal residue} and PD-L3 is identical to PD-L4 {designated the valine (Val) form from the N-terminal residue} and that there are 35 identical residues between the two forms . Furthermore, the Val form presents the same number of identical residues as PD-S2, an RIP isolated from the seeds of the same plant . With the exception of PD-L4, the purified RIPs gave a positive reaction when stained for sugars on SDS-PAGE gels and, when analyzed by electrospray mass spectrometry, had M(r) values of 32,715 +/- 1 (PD-L1), 31,542 +/- 1 (PD-L2), 30,356 +/- 1 (PD-L3) and 29,185 +/- 1 Da (PD-L4) . The 1171 kDa difference in M(r), within the same RIP form, could be due to glycosylation . Like leaf saporins and many other RIPs, the four RIPs released several adenines from poly(A), herring sperm DNA and rRNA 16S + 23S, thus acting as polynucleotide:adenosine glycosidases . This property was less pronounced in PD-L1 and PD-L3 than in PD-L2 and PD-L4, respectively . The proteins PD-L1 and PD-L4 showed 3.7% reactivity with the antiserum anti-dianthin 32 and no reactivity with antisera to PAP-R saporin-S6, momordin 1 and even PD-S2, an RIP isolated from the seeds of the same plant . Protein PD-L4 showed 12.5% cross-reactivity with anti-PD-L1, while the opposite cross-reactivity was 100%. Philos Trans R Soc Lond B Biol Sci, 1999 Mar 29, 354(1383), 613 - 27 Replication of tobacco mosaic virus RNA; Buck KW; The replication of tobacco mosaic virus (TMV) RNA involves synthesis of a negative-strand RNA using the genomic positive-strand RNA as a template, followed by the synthesis of positive-strand RNA on the negative-strand RNA templates . Intermediates of replication isolated from infected cells include completely double-stranded RNA (replicative form) and partly double-stranded and partly single-stranded RNA (replicative intermediate), but it is not known whether these structures are double-stranded or largely single-stranded in vivo . The synthesis of negative strands ceases before that of positive strands, and positive and negative strands may be synthesized by two different polymerases . The genomic-length negative strand also serves as a template for the synthesis of subgenomic mRNAs for the virus movement and coat proteins . Both the virus-encoded 126-kDa protein, which has amino-acid sequence motifs typical of methyltransferases and helicases, and the 183-kDa protein, which has additional motifs characteristic of RNA-dependent RNA polymerases, are required for efficient TMV RNA replication . Purified TMV RNA polymerase also contains a host protein serologically related to the RNA-binding subunit of the yeast translational initiation factor, eIF3 . Study of Arabidopsis mutants defective in RNA replication indicates that at least two host proteins are needed for TMV RNA replication . The tomato resistance gene Tm-1 may also encode a mutant form of a host protein component of the TMV replicase . TMV replicase complexes are located on the endoplasmic reticulum in close association with the cytoskeleton in cytoplasmic bodies called viroplasms, which mature to produce 'X bodies' . Viroplasms are sites of both RNA replication and protein synthesis, and may provide compartments in which the various stages of the virus mutiplication cycle (protein synthesis, RNA replication, virus movement, encapsidation) are localized and coordinated . Membranes may also be important for the configuration of the replicase with respect to initiation of RNA synthesis, and synthesis and release of progeny single-stranded RNA. Diagn Microbiol Infect Dis, 1999 Apr, 33(4), 217 - 22 Trends in species distribution and susceptibility to fluconazole among blood stream isolates of Candida species in the United States; Pfaller MA et al.; National surveillance of blood stream infections (BSI) attributable to Candida spp . has been limited to date . Recent studies have suggested in increase in the proportion of BSI attributable to non-Candida albicans species and have also raised concerns regarding the emergence of antifungal resistance among Candida spp . The increased utilization of broad-spectrum antifungal agents and the recognition of Candida spp . as prominent pathogens with the potential for developing antifungal resistance, emphasize the need for ongoing surveillance of antifungal susceptibility patterns . In this investigation trends in species distribution and susceptibility to fluconazole among BSI isolates of Candida spp . referred to our laboratory by United States hospitals were evaluated over the 7-year period from 1992 to 1998 . A total of 1579 BSI isolates from more than 50 medical centers were processed . Overall, C . albicans accounted for 52% of isolates followed by C . glabrata (18%), C . parapsilosis (15%), C . tropicalis (11%), and C . krusei (2%) . The proportion of BSI isolates that were C . albicans ranged from 45% in 1992 to 60% in 1998 . Among the non-C . albicans isolates, C . glabrata succeeded C . parapsilosis as the most common species beginning in 1995 . Overall, the susceptibility of all Candida species (C . albicans plus all other species) to fluconazole remained stable (MIC90, 16 micrograms/mL) . The fluconazole MIC90 for C . albicans was 0.5-2.0 micrograms/ml for all years studied except 1995 (8.0 micrograms/mL) and was 1.0 microgram/mL overall . The present study suggests a continued prominent role of C . albicans as a cause of BSI, and a constant level of susceptibility of Candida BSI isolates to fluconazole over 7 years . These data should serve as a baseline for future surveillance efforts for anti-fungal agents tested against yeast BSI isolates. J Biol Chem, 1999 Apr 30, 274(18), 12803 - 10 Replacement of threonine 558, a critical site of phosphorylation of moesin in vivo, with aspartate activates F-actin binding of moesin . Regulation by conformational change; Huang L et al.; Point and deletion mutants of moesin were examined for F-actin binding by blot overlay and co-sedimentation, and for intra- and intermolecular interactions with N- and C-terminal domains with yeast two-hybrid and in vitro binding assays . Wild-type moesin molecules interact poorly with F-actin and each other, and bind neither C- nor N-terminal fragments . Interaction with F-actin is strongly enhanced by replacement of Thr558 with aspartate (T558D), by deletion of 11 N-terminal residues (DelN11), by deletion of the entire N-terminal membrane-binding domain of both wild type and T558D mutant molecules, and by exposure to phosphatidylinositol 4, 5-diphosphate . Activation of F-actin binding is accompanied by changes in inter- and intramolecular domain interactions . The T558D mutation renders moesin capable of binding wild type but not mutated (T558D) C-terminal or wild type N-terminal fragments . The interaction between the latter two is prevented . DelN11 truncation enables binding of wild type N and C domain fragments . These changes suggest that the T558D mutation, mimicking phosphorylation of Thr558, promotes F-actin binding by disruption of interdomain interactions between N and C domains and exposure of the high affinity F-actin binding site in the C-terminal domain . Oscillation between activated and resting state could thus provide the structural basis for transient interactions between moesin and the actin cytoskeleton in protruding and retracting microextensions. J Cell Sci, 1999 May, 112 ( Pt 10), 1465 - 76 A novel hnRNP protein (HAP/SAF-B) enters a subset of hnRNP complexes and relocates in nuclear granules in response to heat shock; Weighardt F et al.; A two-hybrid screening in yeast for proteins interacting with the human hnRNP A1, yielded a nuclear protein of 917 amino acids that we termed hnRNP A1 associated protein (HAP) . HAP contains an RNA binding domain (RBD) flanked by a negatively charged domain and by an S/K-R/E-rich region . In in vitro pull-down assays, HAP interacts with hnRNP A1, through its S/K-R/E-rich region, and with several other hnRNPs . HAP was found to be identical to the previously described Scaffold Attachment Factor B (SAF-B) and to HET, a transcriptional regulator of the Heat Shock Protein 27 gene . We show that HAP is a bona fide hnRNP protein, since anti-HAP antibodies immunoprecipitate from HeLa cell nucleoplasm the complete set of hnRNP proteins . Unlike most hnRNP proteins, the subnuclear distribution of HAP is profoundly modified in heat-shocked HeLa cells . Heat-shock treatment at 42 degrees C causes a transcription-dependent recruitment of HAP to a few large nuclear granules that exactly coincide with sites of accumulation of Heat Shock Factor 1 (HSF1) . The recruitment of HAP to the granules is temporally delayed with respect to HSF1 and persists for a longer time during recovery at 37 degrees C . The hnRNP complexes immunoprecipitated from nucleoplasm of heat-shocked cells with anti-HAP antibodies have an altered protein composition with respect to canonical complexes . Altogether our results suggest an involvement of HAP in the cellular response to heat shock, possibly at the RNA metabolism level. Biochim Biophys Acta, 1999 Apr 1, 1449(3), 211 - 6 Isolation of spermidine synthase gene (spsA) of Dictyostelium discoideum; Guo K et al.; The gene encoding spermidine synthase (spsA) was isolated from Dictyostelium discoideum using the technique of insertional mutagenesis . Northern blot analysis showed that the spsA mRNA is expressed maximally during the vegetative stage and decreases gradually during the 24 h of development . Sequencing of the genomic DNA and a full-length cDNA clone indicated the presence of one intron in a gene coding for a predicted protein (SpsA) with 284 amino acids . The sequence is highly conserved, with amino acid identities compared to spermidine synthases of humans, 59.5%, to mouse, 61.3%, and to yeast, 58.1% . A null mutant of the spsA gene is unable to grow in the absence of exogenous spermidine . Development of spsA null cells grown in the absence of spermidine produced fruiting bodies that have abnormally short stalks. Biochim Biophys Acta, 1999 Apr 14, 1418(1), 61 - 70 Transbilayer movement and distribution of spin-labelled phospholipids in the inner mitochondrial membrane; Gallet PF et al.; The transmembrane diffusion and equilibrium distribution of spin-labelled phosphatidylethanolamine (PE*), phosphatidylcholine (PC*) and cardiolipin (CL*) were investigated in purified mitochondrial inner membranes using electron spin resonance spectroscopy . Using the back exchange technique, we found that the outside-inside movement of PE* and PC* in beef-heart inner mitochondrial membranes was rapid (t1/2 in the range 10-15 min at 30 degrees C) . The steady-state distributions in non-energised mitoplasts were approximately 30% in the inner leaflet for PC* and 39% for PE* . Within the limits of probe concentration that can possibly be used in these experiments, the initial velocity of the inward movement was not saturable with respect to the amount of analogue added to the membranes, suggesting that the spin-labelled phospholipids diffused passively between the two leaflets of the inner mitochondrial membrane . In energised mitoplasts, PC* behaviour was not affected, PE* diffused approximately two times faster toward the inner monolayer but reached the same plateau . Treatment of energised mitochondria with N-ethylmaleimide did not affect PC* diffusion, while the kinetics of PE* internalisation became identical to that of PC* . Similar results were found when PC* and PE* movements were studied in mitoplasts from beef heart, rat liver or yeast . The spin-labelled cardiolipin, which possesses four long chains, had to be introduced in the mitoplast with some ethanol . After equilibration (t1/2 of the order of 13 min at 30 degrees C), the transmembrane distribution suggested that approximately half of the cardiolipin analogue remained in the outer leaflet . These results do not allow us to determine if a specific protein (or flippase) is involved in the phospholipid transmembrane traffic within inner mitochondrial membranes, but they show that lipids can rapidly flip through the mitochondrial membrane. Curr Biol, 1999 Apr 8, 9(7), 381 - 4 A novel Rab6-interacting domain defines a family of Golgi-targeted coiled-coil proteins; Barr FA; In recent years, a large number of coiled-coil proteins localised to the Golgi apparatus have been identified using antisera from human patients with a variety of autoimmune conditions {1} . Because of their common method of discovery and extensive regions of coiled-coil, they have been classified as a family of proteins, the golgins {1} . This family includes golgin-230/245/256, golgin-97, GM130/golgin-95, golgin-160/MEA-2/GCP170, giantin/macrogolgin and a related group of proteins - possibly splice variants - GCP372 and GCP364{2}{3}{4}{5}{6}{7}{8}{9}{10}{11} . GM130 and giantin have been shown to function in the p115-mediated docking of vesicles with Golgi cisternae {12} . In this process, p115, another coiled-coil protein, is though to bind to giantin on vesicles and to GM130 on cisternae, thus acting as a tether holding the two together {12} {13} . Apart from giantin and GM130, none of the golgins has yet been assigned a function in the Golgi apparatus . In order to obtain clues as to the functions of the golgins, the targeting to the Golgi apparatus of two members of this family, golgin-230/245/256 and golgin-97, was investigated . Each of these proteins was shown to target to the Golgi apparatus through a carboxy-terminal domain containing a conserved tyrosine residue, which was critical for targeting . The domain preferentially bound to Rab6 on protein blots, and mutations that abolished Golgi targeting resulted in a loss of this interaction . Sequence analysis revealed that a family of coiled-coil proteins from mammals, worms and yeast contain this domain at their carboxyl termini . One of these proteins, yeast Imh1p, has previously been shown to have a tight genetic interaction with Rab6 {14} . On the basis of these data, it is proposed that this family of coiled-coil proteins functions in Rab6-regulated membrane-tethering events. Curr Biol, 1999 Apr 8, 9(7), 377 - 80 The GRIP domain - a novel Golgi-targeting domain found in several coiled-coil proteins; Munro S et al.; Many large coiled-coil proteins are being found associated peripherally with the cytoplasmic face of the organelles of the secretory pathway . Various roles have been proposed for these proteins, including the docking of donor vesicles or organelles to an acceptor organelle prior to fusion, and, in the case of the Golgi apparatus, the stacking of the cisternae {1} {2} {3} {4} {5} . Such critical roles require accurate recruitment to the correct organelle . For the endosomal coiled-coil protein EEA1, targeting requires a carboxy-terminal FYVE domain, which interacts with Rab5 and phosphatidylinositol 3-phosphate (PI(3)P), whereas the Golgi protein GM130 interacts with Golgi membranes via the protein GRASP65 {3} {6} {7} . In this paper, we show that two other mammalian Golgi coiled-coil proteins, golgin-245/p230 and golgin-97, have a conserved domain of about 50 amino acids at their carboxyl termini . This 'GRIP' domain is also found at the carboxyl terminus of several other large coiled-coiled proteins of unknown function, including two human proteins and proteins in the genomes of Caenorhabditis elegans and yeasts . The GRIP domains from several of these proteins, including that from the yeast protein Imh1p, were sufficient to specify Golgi targeting in mammalian cells when fused to green fluorescent protein (GFP) . This result suggests that this small domain functions to recruit specific coiled-coil proteins to the Golgi by recognising a determinant that has been well conserved in eukaryotic evolution. Curr Biol, 1999 Apr 8, 9(7), 341 - 50 A DNA unwinding factor involved in DNA replication in cell-free extracts of Xenopus eggs; Okuhara K et al.; BACKGROUND: Alteration of chromatin structure is a key step in various aspects of DNA metabolism . DNA unwinding factors such as the high mobility group (HMG) proteins are thought to play a general role in controlling chromatin structure and a specific role in controlling DNA replication . For instance, in the in vitro simian virus 40 replication system, minichromosomes containing HMG-17 replicate more efficiently than those without it, suggesting that HMG-17 enhances the rate of replication of a chromatin template by unfolding the higher-order chromatin structure . At present, however, only limited data suggest an involvement of DNA unwinding factors in DNA replication . RESULTS: We purified from Xenopus eggs a novel heterodimeric factor, termed DNA unwinding factor (DUF), that consists of 87 kDa and 140 kDa polypeptides . DUF unwinds closed-circular duplex DNA in the presence of topoisomerase I, but it does not possess a DNA gyrase activity: it does not introduce negative supercoils into DNA at the expense of ATP hydrolysis . Cloning and sequencing of the cDNAs encoding the two polypeptides revealed that the 87 kDa polypeptide is homologous to a mammalian HMG protein, T160/structure-specific recognition protein . The 140 kDa polypeptide is homologous to yeast Cdc68, a protein that controls the expression of several genes during the G1 phase of the cell cycle by modulating chromatin structure . Immunodepletion of DUF from Xenopus egg extracts drastically reduced the ability of the extract to replicate exogenously added sperm chromatin or plasmid DNA . CONCLUSIONS: We propose that DUF plays a role in DNA replication in Xenopus egg extracts. J Cell Biol, 1999 Apr 19, 145(2), 317 - 30 Rac homologues and compartmentalized phosphatidylinositol 4, 5-bisphosphate act in a common pathway to regulate polar pollen tube growth; Kost B et al.; Pollen tube cells elongate based on actin- dependent targeted secretion at the tip . Rho family small GTPases have been implicated in the regulation of related processes in animal and yeast cells . We have functionally characterized Rac type Rho family proteins that are expressed in growing pollen tubes . Expression of dominant negative Rac inhibited pollen tube elongation, whereas expression of constitutive active Rac induced depolarized growth . Pollen tube Rac was found to accumulate at the tip plasma membrane and to physically associate with a phosphatidylinositol monophosphate kinase (PtdIns P-K) activity . Phosphatidylinositol 4, 5-bisphosphate (PtdIns 4, 5-P2), the product of PtdIns P-Ks, showed a similar intracellular localization as Rac . Expression of the pleckstrin homology (PH)-domain of phospholipase C (PLC)-delta1, which binds specifically to PtdIns 4, 5-P2, inhibited pollen tube elongation . These results indicate that Rac and PtdIns 4, 5-P2 act in a common pathway to control polar pollen tube growth and provide direct evidence for a function of PtdIns 4, 5-P2 compartmentalization in the regulation of this process. Neuroreport, 1999 Feb 25, 10(3), 563 - 8 Isolation of human delta-catenin and its binding specificity with presenilin 1; Tanahashi H et al.; We screened proteins for interaction with presenilin (PS) 1, and cloned the full-length cDNA of human delta-catenin, which encoded 1225 amino acids . Yeast two-hybrid assay, GST binding assay and immunoprecipitation demonstrated that delta-catenin interacted with a hydrophilic loop region in the endoproteolytic C-terminal fragment of PS1, but not with that of PS-2 . These results suggest that PS1 and PS2 partly differ in function . PS1 loop fragment containing the pathogenic mutation retained the binding ability . We also found another armadillo-protein, p0071, interacted with PS1. Development, 1999 May, 126(10), 2227 - 39 The Caenorhabditis elegans gene ncc-1 encodes a cdc2-related kinase required for M phase in meiotic and mitotic cell divisions, but not for S phase; Boxem M et al.; We have identified six protein kinases that belong to the family of cdc2-related kinases in Caenorhabditis elegans . Results from RNA interference experiments indicate that at least one of these kinases is required for cell-cycle progression during meiosis and mitosis . This kinase, encoded by the ncc-1 gene, is closely related to human Cdk1/Cdc2, Cdk2 and Cdk3 and yeast CDC28/cdc2(+) . We addressed whether ncc-1 acts to promote passage through a single transition or multiple transitions in the cell cycle, analogous to Cdks in vertebrates or yeasts, respectively . We isolated five recessive ncc-1 mutations in a genetic screen for mutants that resemble larval arrested ncc-1(RNAi) animals . Our results indicate that maternal ncc-1 product is sufficient for embryogenesis, and that zygotic expression is required for cell divisions during larval development . Cells that form the postembryonic lineages in wild-type animals do not enter mitosis in ncc-1 mutants, as indicated by lack of chromosome condensation and nuclear envelope breakdown . However, progression through G1 and S phase appears unaffected, as revealed by expression of ribonucleotide reductase, incorporation of BrdU and DNA quantitation . Our results indicate that C . elegans uses multiple Cdks to regulate cell-cycle transitions and that ncc-1 is the C . elegans ortholog of Cdk1/Cdc2 in other metazoans, required for M phase in meiotic as well as mitotic cell cycles. Mol Cell Biol, 1999 May, 19(5), 3614 - 23 The catenin p120(ctn) interacts with Kaiso, a novel BTB/POZ domain zinc finger transcription factor; Daniel JM et al.; p120(ctn) is an Armadillo repeat domain protein with structural similarity to the cell adhesion cofactors beta-catenin and plakoglobin . All three proteins interact directly with the cytoplasmic domain of the transmembrane cell adhesion molecule E-cadherin; beta-catenin and plakoglobin bind a carboxy-terminal region in a mutually exclusive manner, while p120 binds the juxtamembrane region . Unlike beta-catenin and plakoglobin, p120 does not interact with alpha-catenin, the tumor suppressor adenomatous polyposis coli (APC), or the transcription factor Lef-1, suggesting that it has unique binding partners and plays a distinct role in the cadherin-catenin complex . Using p120 as bait, we conducted a yeast two-hybrid screen and identified a novel transcription factor which we named Kaiso . Kaiso's deduced amino acid sequence revealed an amino-terminal BTB/POZ protein-protein interaction domain and three carboxy-terminal zinc fingers of the C2H2 DNA-binding type . Kaiso thus belongs to a rapidly growing family of POZ-ZF transcription factors that include the Drosophila developmental regulators Tramtrak a