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See detailTranscription factor TFIIH and DNA endonuclease Rad2 constitute yeast nucleotide excision repair factor 3: implications for nucleotide excision repair and Cockayne syndrome
Habraken, Yvette ULg; Sung, Patrick; Prakash, Louise et al

in Proceedings of the National Academy of Sciences of the United States of America (1996), 93(20), 10718-22

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See detailExpression of protein encoded by varicella-zoster virus open reading frame 63 in latently infected human ganglionic neurons
Mahalingam, Ravy; Wellish, Mary; Cohrs, Randall et al

in Proceedings of the National Academy of Sciences of the United States of America (1996), 93(5), 2122-2124

The ganglionic cell type in which varicellazoster virus (VZV) is latent in humans was analyzed by using antibodies raised against in vitro-expressed VZV open reading frame 63 protein, VZV open reading ... [more ▼]

The ganglionic cell type in which varicellazoster virus (VZV) is latent in humans was analyzed by using antibodies raised against in vitro-expressed VZV open reading frame 63 protein, VZV open reading frame 63 protein was detected exclusively in the cytoplasm of neurons of latently infected human trigeminal and thoracic ganglia. This is, to our knowledge, the first identification of a herpesvirus protein expressed during latency in the human nervous system. [less ▲]

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See detailThe catalytic mechanism of beta-lactamases: NMR titration of an active-site lysine residue of the TEM-1 enzyme.
Damblon, Christian ULg; Raquet, X.; Lian, L. Y. et al

in Proceedings of the National Academy of Sciences of the United States of America (1996), 93(5), 1747-52

Beta-Lactamases are widespread in the bacterial world, where they are responsible for resistance to penicillins, cephalosporins, and related compounds, currently the most widely used antibacterial agents ... [more ▼]

Beta-Lactamases are widespread in the bacterial world, where they are responsible for resistance to penicillins, cephalosporins, and related compounds, currently the most widely used antibacterial agents. Detailed structural and mechanistic understanding of these enzymes can be expected to guide the design of new antibacterial compounds resistant to their action. A number of high-resolution structures are available for class A beta-lactamases, whose catalytic mechanism involves the acylation of a serine residue at the active site. The identity of the general base which participates in the activation of this serine residue during catalysis has been the subject of controversy, both a lysine residue and a glutamic acid residue having been proposed as candidates for this role. We have used the pH dependence of chemical modification of epsilon-amino groups by 2,4,6,-trinitrobenzenesulfonate and the pH dependence of the epsilon-methylene 1H and 13C chemical shifts (in enzyme selectively labeled with [epsilon-13C]lysine) to estimate the pKa of the relevant lysine residue, lysine-73, of TEM-1 beta-lactamase. Both methods show that the pKa of this residue is > 10, making it very unlikely that this residue could act as a proton acceptor in catalysis. An alternative mechanism in which this role is performed by glutamate-166 through an intervening water molecule is described. [less ▲]

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See detailEmergence of the ZNF91 Kruppel-associated box-containing zinc finger gene family in the last common ancestor of anthropoidea
Bellefroid, Eric J.; Marine, Jean-Christophe; Matera, A Gregory et al

in Proceedings of the National Academy of Sciences of the United States of America (1995), 92(23), 10757-61

The ZNF91 gene family, a subset of the Kruppel-associated box (KRAB)-containing group of zinc finger genes, comprises more than 40 loci; most reside on human chromosome 19p12-p13.1. We have examined the ... [more ▼]

The ZNF91 gene family, a subset of the Kruppel-associated box (KRAB)-containing group of zinc finger genes, comprises more than 40 loci; most reside on human chromosome 19p12-p13.1. We have examined the emergence and evolutionary conservation of the ZNF91 family. ZNF91 family members were detected in all species of great apes, gibbons, Old World monkeys, and New World monkeys examined but were not found in prosimians or rodents. In each species containing the ZNF91 family, the genes were clustered at one major site, on the chromosome(s) syntenic to human chromosome 19. To identify a putative "founder" gene, > 20 murine KRAB-containing zinc finger protein (ZFP) cDNAs were randomly cloned, but none showed sequence similarity to the ZNF91 genes. These observations suggest that the ZNF91 gene cluster is a derived character specific to Anthropoidea, resulting from a duplication and amplification event some 55 million years ago in the common ancestor of simians. Although the ZNF91 gene cluster is present in all simian species, the sequences of the human ZNF91 gene that confer DNA-binding specificity were conserved only in great apes, suggesting that there is not a high selective pressure to maintain the DNA targets of these proteins during evolution. [less ▲]

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See detailActivation of mitogen-activated protein kinases by vascular endothelial growth factor and basic fibroblast growth factor in capillary endothelial cells is inhibited by the antiangiogenic factor 16-kDa N-terminal fragment of prolactin
D'Angelo, Gisela; Struman, Ingrid ULg; Martial, Joseph ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (1995), 92(14), 6374-8

A number of factors both stimulating and inhibiting angiogenesis have been described. In the current work, we demonstrate that the angiogenic factor vascular endothelial growth factor (VEGF) activates ... [more ▼]

A number of factors both stimulating and inhibiting angiogenesis have been described. In the current work, we demonstrate that the angiogenic factor vascular endothelial growth factor (VEGF) activates mitogen-activated protein kinase (MAPK) as has been previously shown for basic fibroblast growth factor. The antiagiogenic factor 16-kDa N-terminal fragment of human prolactin inhibits activation of MAPK distal to autophosphorylation of the putative VEGF receptor, Flk-1, and phospholipase C-gamma. These data show that activation and inhibition of MAPK may play a central role in the control of angiogenesis. [less ▲]

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See detailAttenuation Of Bovine Leukemia-Virus By Deletion Of R3 And G4 Open Reading Frames
Willems, Luc ULg; Kerkhofs, P.; Dequiedt, Franck ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (1994), 91(24),

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See detailChromosomal localization of the callipyge gene in sheep (Ovis aries) using bovine DNA markers
Cockett, N. E.; Jackson, S. P.; Shay, T. D. et al

in Proceedings of the National Academy of Sciences of the United States of America (1994), 91

A mutation causing muscular hypertrophy, with associated leanness and improved feed efficiency, has been recently identified in domestic sheep (Ovis aries). Preliminary results indicate that an autosomal ... [more ▼]

A mutation causing muscular hypertrophy, with associated leanness and improved feed efficiency, has been recently identified in domestic sheep (Ovis aries). Preliminary results indicate that an autosomal dominant gene may be responsible for this economically advantageous trait. We have exploited the conservation in sequence and chromosomal location of DNA markers across Bovidae to map the corresponding callipyge locus to ovine chromosome 18 using a battery of bovine chromosome 21 markers. Chromosomal localization of the ovine callipyge locus is the first step toward positional cloning of the corresponding gene. [less ▲]

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See detailMicrosatellite mapping of the gene causing weaver disease in cattle will allow the study of an associated QTL
Georges, Michel ULg; Lathrop, M.; Dietz, A. B. et al

in Proceedings of the National Academy of Sciences of the United States of America (1993), 90

A genetic disease in cattle, progressive degenerative myeloencephalopathy (weaver disease), is associated with increased milk production. This association could result from population stratification, from ... [more ▼]

A genetic disease in cattle, progressive degenerative myeloencephalopathy (weaver disease), is associated with increased milk production. This association could result from population stratification, from a pleiotropic effect of a single gene, or from linkage disequilibrium between the gene causing weaver disease and a quantitative trait locus (QTL) for milk production. To test these hypotheses, we performed an extensive linkage study in a bovine pedigree segregating for the weaver condition and identified a microsatellite locus (TGLA116) closely linked to the weaver gene (zmax, 8.15; theta, 0.03). TGLA116 and, by extension, the weaver locus were assigned to bovine synteny group 13. This microsatellite can be used to identify weaver carriers, to select against this genetic defect, and to study the effect of the corresponding chromosomal region on milk production in Brown Swiss and other breeds of cattle. [less ▲]

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See detailMutations In The Bovine Leukemia-Virus Tax Protein Can Abrogate The Long Terminal Repeat-Directed Transactivating Activity Without Concomitant Loss Of Transforming Potential
Willems, Luc ULg; Grimonpont, C.; Heremans, H. et al

in Proceedings of the National Academy of Sciences of the United States of America (1992), 89(9),

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See detailFusogenic Segments Of Bovine Leukemia-Virus And Simian Immunodeficiency Virus Are Interchangeable And Mediate Fusion By Means Of Oblique Insertion In The Lipid Bilayer Of Their Target-Cells
Voneche, V.; Portetelle, Daniel ULg; Kettmann, Richard ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (1992), 89(9),

Modified bovine leukemia virus (BLV) glycoproteins were expressed by using vaccinia virus recombinants, and their fusogenic capacities were examined by a syncytia-formation assay. This analysis indicates ... [more ▼]

Modified bovine leukemia virus (BLV) glycoproteins were expressed by using vaccinia virus recombinants, and their fusogenic capacities were examined by a syncytia-formation assay. This analysis indicates that (i) both BLV envelope glycoproteins gp51 and gp30 are necessary for cell fusion; (ii) insertion of the N-terminal segment of gp30 (fusion peptide) into the lipid bilayer in an oblique orientation, as predicted by computer conformational analysis, results in fusogenic capacities higher than insertion in a perpendicular or parallel orientation; and (iii) replacement of the BLV fusion peptide with its simian immunodeficiency virus counterpart does not modify the fusogenic capacity of the BLV glycoprotein. [less ▲]

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See detailIdentification of the major pregnancy-specific antigens of cattle and sheep as inactive members of the aspartic proteinase family
Xie, Sancai; Low, Boon G.; Nagel, Robert J. et al

in Proceedings of the National Academy of Sciences of the United States of America (1991), 88(22), 10247-10251

Pregnancy in cattle and sheep can be diagnosed by the presence of a conceptus-derived antigen in maternal serum that is secreted by trophoblast and placental tissue primarily as an acidic component of Mr ... [more ▼]

Pregnancy in cattle and sheep can be diagnosed by the presence of a conceptus-derived antigen in maternal serum that is secreted by trophoblast and placental tissue primarily as an acidic component of Mr 67,000. Molecular cloning of its cDNA reveals that the antigen belongs to the aspartic proteinase family and has greater than 50% amino acid sequence identity to pepsin, cathepsin D, and cathepsin E. The inferred sequences of the ovine and bovine polypeptides show approximately 73% identity to each other. Critical amino acid substitutions at the active site regions suggest that both proteins are enzymatically inactive. The antigen is a product of trophoblast binucleate cells that invade maternal endometrium at implantation sites. [less ▲]

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See detailCYTODUCTION IN CHLAMYDOMONAS-REINHARDTII
Matagne, René-Fernand ULg; Remacle, Claire ULg; DINANT, M.

in Proceedings of the National Academy of Sciences of the United States of America (1991), 88(16), 7447-7450

After conjugation between Chlamydomonas gametes of opposite mating type, a transient dikaryon is formed. The two nuclei fuse within 4-6 hr after mating. The young diploid zygote differentiates into ... [more ▼]

After conjugation between Chlamydomonas gametes of opposite mating type, a transient dikaryon is formed. The two nuclei fuse within 4-6 hr after mating. The young diploid zygote differentiates into dormant zygospore competent to complete meiosis, or more rarely (2-10% of cases) it undergoes mitosis to produce a stable diploid progeny. We here bring genetical, biochemical, and cytological evidence that among the mitotic zygotes, a large proportion of them undergo cytokinesis without fusion of the nuclei - a process that has been termed "cytoduction." By using appropriate genetic markers, haploid cytoductants that possess the nuclear genotype of one parent and the chloroplast marker of the other parent can easily be isolated. Genetical analysis and hybridization experiments moreover show that many haploid cytoductants transmit the chloroplast DNA molecules of both parents and that, as in diploids, these DNA copies occasionally recombine. This process of cytoduction extends the life cycle of Chlamydomonas and provides new tools for its genetic analysis. [less ▲]

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See detailThe evolutionarily conserved Kruppel-associated box domain defines a subfamily of eukaryotic multifingered proteins
Bellefroid, Eric J.; Poncelet, Dominique A; Lecocq, Pierre J et al

in Proceedings of the National Academy of Sciences of the United States of America (1991), 88(9), 3608-12

We have previously shown that the human genome includes hundreds of genes coding for putative factors related to the Kruppel zinc-finger protein, which regulates Drosophila segmentation. We report herein ... [more ▼]

We have previously shown that the human genome includes hundreds of genes coding for putative factors related to the Kruppel zinc-finger protein, which regulates Drosophila segmentation. We report herein that about one-third of these genes code for proteins that share a very conserved region of about 75 amino acids in their N-terminal nonfinger portion. Homologous regions are found in a number of previously described finger proteins, including mouse Zfp-1 and Xenopus Xfin. We named this region the Kruppel-associated box (KRAB). This domain has the potential to form two amphipathic alpha-helices. Southern blot analysis of "zoo" blots suggests that the Kruppel-associated box is highly conserved during evolution. Northern blot analysis shows that these genes are expressed in most adult tissues and are down-regulated during in vitro terminal differentiation of human myeloid cells. [less ▲]

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See detailEven Transcriptionally Competent Proviruses Are Silent In Bovine Leukemia Virus-Induced Sheep Tumor-Cells
Vandenbroeke, A.; Cleuter, Y.; Chen, G. et al

in Proceedings of the National Academy of Sciences of the United States of America (1988), 85(23),

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See detailTransferrin receptors in rat plasma.
Beguin, Yves ULg; Huebers, H. A.; Josephson, B. et al

in Proceedings of the National Academy of Sciences of the United States of America (1988), 85(2), 637-40

Antigenic material in rat plasma reacting with rat transferrin receptor antibodies was identified as an intact receptor molecule complexed with transferrin. Plasma transferrin receptors were measured by ... [more ▼]

Antigenic material in rat plasma reacting with rat transferrin receptor antibodies was identified as an intact receptor molecule complexed with transferrin. Plasma transferrin receptors were measured by ELISA in rats of different age and sex, of different iron status, with different degrees of erythropoiesis, and with inflammation. An inverse relationship between iron status and receptor number was found, whereas a direct relationship existed between erythropoiesis and receptors. These changes in receptor number can be explained by assuming that the number of tissue receptors determined the number of plasma receptors and that the erythroid cells possessed most of the body's receptors. Increases in plasma receptors lagged behind the appearance of circulating reticulocytes, suggesting that receptors were released to the plasma during the terminal phase of erythrocyte maturation. [less ▲]

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See detailExpression of a synthetic gene encoding human insulin-like growth factor I in cultured mouse fibroblasts.
Bayne, M. L.; Cascieri, M. A.; Kelder, B. et al

in Proceedings of the National Academy of Sciences of the United States of America (1987), 84

A synthetic gene encoding human insulin-like growth factor I (hIGF-I) was assembled and inserted into an expression vector containing the cytomegalovirus immediate early (CMV-IE) transcriptional ... [more ▼]

A synthetic gene encoding human insulin-like growth factor I (hIGF-I) was assembled and inserted into an expression vector containing the cytomegalovirus immediate early (CMV-IE) transcriptional regulatory region and portions of the bovine growth hormone gene. The recombinant plasmid encodes a 97 amino acid fusion protein containing the first 27 amino acids of the bovine growth hormone precursor and the 70 amino acids of hIGF-I. This plasmid, when transiently introduced into cultured mouse fibroblasts, directs synthesis of the fusion protein, subsequent proteolytic removal of the bovine growth hormone signal peptide, and secretion of hIGF-I into the culture medium. Conditioned medium from transfected cells inhibits binding of 125I-labeled IGF-I to type I IGF receptors on human placental membranes and to acid-stable human serum carrier proteins. The recombinant hIGF-I produced is biologically active, as monitored by the stimulation of DNA synthesis in vascular smooth muscle cells. [less ▲]

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See detailThyroid hormone receptors bind to defined regions of the growth hormone and placental lactogen genes
Barlow, John W; Voz, Marianne ULg; Eliard, Pierre H et al

in Proceedings of the National Academy of Sciences of the United States of America (1986), 83(23), 9021-5

The intracellular receptor for thyroid hormone is a protein found in chromatin. Since thyroid hormone stimulates transcription of the growth hormone gene through an unknown mechanism, the hypothesis that ... [more ▼]

The intracellular receptor for thyroid hormone is a protein found in chromatin. Since thyroid hormone stimulates transcription of the growth hormone gene through an unknown mechanism, the hypothesis that the thyroid hormone-receptor complex interacts with defined regions of this gene has been investigated in a cell-free system. Nuclear extracts from human lymphoblastoid IM-9 cells containing thyroid hormone receptors were incubated with L-3,5,3'-tri[125I]iodothyronine and calf thymus DNA-cellulose. Restriction fragments of the human growth hormone gene were added to determine their ability to inhibit labeled receptor binding to DNA-cellulose. These fragments encompassed nucleotide sequences from about three kilobase pairs upstream to about four kilobase pairs downstream from the transcription initiation site. The thyroid hormone-receptor complex bound preferentially to the 5'-flanking sequences of the growth hormone gene in a region between nucleotide coordinates -290 and -129. The receptor also bound to an analogous promoter region in the human placental lactogen gene, which has 92% nucleotide sequence homology with the growth hormone gene. These binding regions appear to be distinct from those that are recognized by the receptor for glucocorticoids, which stimulate growth hormone gene expression synergistically with thyroid hormone. The presence of thyroid hormone was required for binding of its receptor to the growth hormone gene promoter, suggesting that thyroid hormone renders the receptor capable of recognizing specific gene regions. [less ▲]

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See detailConformational analysis of the calcium--A23187 complex at a lipid--water interface.
Brasseur, Robert ULg; Deleers, M.; Malaisse, W. J. et al

in Proceedings of the National Academy of Sciences of the United States of America (1982), 79(9), 2895-7

A possible conformation of the complex formed by one calcium ion and two molecules of the ionophore A23187 at a simulated lipid--water interface was predicted by a variant method for conformational ... [more ▼]

A possible conformation of the complex formed by one calcium ion and two molecules of the ionophore A23187 at a simulated lipid--water interface was predicted by a variant method for conformational analysis. This method takes into account, in addition to the Van der Waals energy, electrostatic interaction, and torsional potential, the alteration of electrostatic forces attributable to changes in dielectric constant at the interface and the transfer energy for each part of the complex as it moves through the lipid-water interface. The most probable conformer was characterized by a two-fold axial symmetry that was maintained during transition to the hydrophobic bulk conformation. Minor changes in the interfacial structure were sufficient to achieve the configuration characteristic of the hydrophobic bulk phase. [less ▲]

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See detailRegulation of growth hormone messenger RNA by thyroid and glucocorticoid hormones
Martial, Joseph ULg; Baxter, John D; Goodman, Howard M et al

in Proceedings of the National Academy of Sciences of the United States of America (1977), 74(5), 1816-20

Thyroid and glucocorticoid hormones stimulate growth hormone synthesis in cultured rat pituitary cells (GC). We have compared changes in growth hormone production and mRNA in these cells. Triiodothyronine ... [more ▼]

Thyroid and glucocorticoid hormones stimulate growth hormone synthesis in cultured rat pituitary cells (GC). We have compared changes in growth hormone production and mRNA in these cells. Triiodothyronine (10 nM) and dexamethasone (1 micron) stimulated increases in growth hormone production by 2.5- and 3.8-fold, respectively. There were corresponding increases in the capacity of RNA from hormone-treated cells to direct synthesis of pregrowth hormone in a wheat germ cell-free translation system, suggesting hormone-regulated increases in growth hormone mRNA. Hormone-induced changes in mRNA were also demonstrated by determining the kinetics of hybridization of a cDNA probe prepared from RNA enriched (about 70%) for growth hormone translational activity with RNA from control and hormone-treated cells. These results suggest that thyroid and glucocorticoid hormones can regulate growth hormone production by influencing the levels of its mRNA. [less ▲]

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See detailRegulation of growth hormone gene expression: synergistic effects of thyroid and glucocorticoid hormones
Martial, Joseph ULg; Seeburg, Peter H; Guenzi, Doris et al

in Proceedings of the National Academy of Sciences of the United States of America (1977), 74(10), 4293-4295

Cultured rat pituitary cells (GC) respond to thyroid and glucocorticoid hormones by increases in growth hormone production and growth hormone mRNA. When these cells are transferred from medium containing ... [more ▼]

Cultured rat pituitary cells (GC) respond to thyroid and glucocorticoid hormones by increases in growth hormone production and growth hormone mRNA. When these cells are transferred from medium containing normal animal serum (with 1.8 mug of thyroxine per dl) to a medium containing serum from a thyroidectomized calf, "hypothyroid medium" (with no detectable thyroid hormone), growth hormone production decreases markedly. In cells maintained for 5 days in hypothyroid medium, triiodothyronine induces within 50 hr a 17-fold increase in growth hormone production whereas glucocorticoids, during the same time, produce a negligible (3-fold or less) stimulation. In combination, the two hormones promote a 45-fold stimulation. In all instances the changes in growth hormone production are paralleled by changes in the levels of growth hormone mRNA as measured by cell-free translation. The transfer to hypothyroid medium and the hormonal induction do not affect the relative activities of other mRNAs whose products are detectable on polyacrylamide gels. These studies indicate that thyroid hormone can be an activator of the expression of the growth hormone gene. The results also show that triiodothyronine controls the magnitude of the effect of glucocorticoids on growth hormone mRNA, and provide a model for "permissive" triiodothyronine action. The synergistic effect of these two classes of hormone suggests that they increase levels of growth hormone mRNA by different mechanisms. [less ▲]

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