References of "Muller, Marc"
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See detailHeat shock stimulation of a tilapia heat shock protein 70 promoter is mediated by a distal element
Molina, Alfredo; Di Martino, Emmanuel; Martial, Joseph ULg et al

in Biochemical Journal (2001), 356(Pt 2), 353-9

We reported previously that a tilapia (Oreochromis mossambicus) heat shock protein 70 (HSP70) promoter is able to confer heat shock response on a reporter gene after transient expression both in cell ... [more ▼]

We reported previously that a tilapia (Oreochromis mossambicus) heat shock protein 70 (HSP70) promoter is able to confer heat shock response on a reporter gene after transient expression both in cell culture and in microinjected zebrafish embryos. Here we present the first functional analysis of a fish HSP70 promoter, the tiHSP70 promoter. Using transient expression experiments in carp EPC (epithelioma papulosum cyprini) cells and in microinjected zebrafish embryos, we show that a distal heat shock response element (HSE1) at approx. -800 is predominantly responsible for the heat shock response of the tiHSP70 promoter. This element specifically binds an inducible transcription factor, most probably heat shock factor, and a constitutive factor. The constitutive complex is not observed with the non-functional, proximal HSE3 sequence, suggesting that both factors are required for the heat shock response mediated by HSE1. [less ▲]

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See detailGene structure and promoter function of a teleost ribosomal protein: a tilapia (Oreochromis mossambicus) L18 gene
Molina, Alfredo; Iyengar, Arati; Marins, Luis F. et al

in Biochimica et Biophysica Acta (2001), 1520(3), 195-202

We have cloned and characterized a tilapia (Oreochromis mossambicus) L18 ribosomal protein gene, including the complete transcribed region and 488 bp of upstream regulatory sequences. We have also ... [more ▼]

We have cloned and characterized a tilapia (Oreochromis mossambicus) L18 ribosomal protein gene, including the complete transcribed region and 488 bp of upstream regulatory sequences. We have also isolated two L18 cDNAs from another tilapia (Oreochromis niloticus) with a few conservative nucleotide differences. Our results suggest the presence of two genes in both species. Reporter constructs were tested for transient expression in CV1 cells and in microinjected zebrafish and tilapia embryos. The tilapia L18 promoter was able to drive expression of the reporter gene in all three experiments, with no apparent preference for a particular tissue. The tilapia L18 promoter is therefore likely to be a powerful tool to drive tissue-independent gene expression in fish. [less ▲]

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See detailThe ornithine decarboxylase gene is essential for cell survival during early murine development
Pendeville-Samain, Hélène ULg; Carpino, Nick; Marine, Jean-Christophe et al

in Molecular & Cellular Biology (2001), 21(19), 6549-58

Overexpression and inhibitor studies have suggested that the c-Myc target gene for ornithine decarboxylase (ODC), the enzyme which converts ornithine to putrescine, plays an important role in diverse ... [more ▼]

Overexpression and inhibitor studies have suggested that the c-Myc target gene for ornithine decarboxylase (ODC), the enzyme which converts ornithine to putrescine, plays an important role in diverse biological processes, including cell growth, differentiation, transformation, and apoptosis. To explore the physiological function of ODC in mammalian development, we generated mice harboring a disrupted ODC gene. ODC-heterozygous mice were viable, normal, and fertile. Although zygotic ODC is expressed throughout the embryo prior to implantation, loss of ODC did not block normal development to the blastocyst stage. Embryonic day E3.5 ODC-deficient embryos were capable of uterine implantation and induced maternal decidualization yet failed to develop substantially thereafter. Surprisingly, analysis of ODC-deficient blastocysts suggests that loss of ODC does not affect cell growth per se but rather is required for survival of the pluripotent cells of the inner cell mass. Therefore, ODC plays an essential role in murine development, and proper homeostasis of polyamine pools appears to be required for cell survival prior to gastrulation. [less ▲]

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See detailInhibition of protein phosphatase PP1 in GH3B6, but not in GH3 cells, activates the MEK/ERK/c-fos pathway and the human prolactin promoter, involving the coactivator CPB/p300
Manfroid, Isabelle ULg; Martial, Joseph ULg; Muller, Marc ULg

in Molecular Endocrinology (Baltimore, Md.) (2001), 15(4), 625-37

The human (hPRL) PRL gene proximal promoter (-164/+15) is the target for numerous signal transduction pathways involving protein kinases. The inhibitor of Ser/Thr-protein phosphatases okadaic acid (OA ... [more ▼]

The human (hPRL) PRL gene proximal promoter (-164/+15) is the target for numerous signal transduction pathways involving protein kinases. The inhibitor of Ser/Thr-protein phosphatases okadaic acid (OA) was shown to induce this promoter in rat pituitary GH3B6 through a synergism between increased amounts of the ubiquitous factor AP-1 and the pituitary-specific factor Pit-1. Here we show that this activation results mainly from transcriptional stimulation of the c-fos promoter leading to increased AP-1 activity. We report the surprising absence of the hPRL and c-fos promoter stimulation by OA in GH3 cells, closely related to GH3B6 cells, and we use this discrepancy to dissect the precise mechanism of action. c-fos gene activation involves the mitogen-activated kinase (MAPK)-ternary complex factor (TCF) pathway and can be obtained by expressing active V12ras in both cell lines. We show that OA acts by inhibiting protein phosphatase PP1, thereby protecting MAPK kinase (MEK)1/2 and/or a MEK1/2-kinase from dephosphorylation. PP1 inhibition of MEK activation by V12ras does not occur in GH3 cells, indicating that a distinct, PP1-sensitive phosphorylation site is used in GH3B6 cells to activate the TCF pathway in GH3B6 cells. Finally, we show that the synergistic OA activation of the hPRL promoter by Pit-1 and AP-1 is independent of the Pit-1 transactivation domain and is mediated by the general coactivator (CRE-binding protein)-binding protein (CBP)/p300. [less ▲]

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See detailCloning and expression analysis of an inducible HSP70 gene from tilapia fish
Molina, Alfredo; Biemar, Frédéric; Muller, Ferenc et al

in FEBS Letters (2000), 474(1), 5-10

We isolated and characterized the tilapia (Oreochromis mossambicus) HSP70 gene, highly homologous to other HSP70 genes. A dramatic increase of tilapia HSP70 mRNA levels was observed after heat shock of ... [more ▼]

We isolated and characterized the tilapia (Oreochromis mossambicus) HSP70 gene, highly homologous to other HSP70 genes. A dramatic increase of tilapia HSP70 mRNA levels was observed after heat shock of whole animals in all organs tested. Reporter constructs were tested for transient expression in carp cells and in microinjected zebrafish embryos. The entire isolated regulatory region (-851/+157) was able to mediate heat shock inducible expression of the reporter gene, with no preference for a particular tissue. Our studies represent the first transcriptional analysis of a HSP70 promoter from fish, revealing a powerful tool to direct controlled, tissue-independent gene expression in fish. [less ▲]

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See detailSilencing subdomains of v-ErbA interact cooperatively with corepressors: involvement of helices 5/6
Busch, Kerstin; Martin, Bernd; Baniahmad, Aria et al

in Molecular Endocrinology (Baltimore, Md.) (2000), 14(2), 201-11

Members of the thyroid hormone receptor (TR) family act on vertebrate development and homeostasis by activating or repressing transcription of specific target genes in a ligand-dependent way. Repression ... [more ▼]

Members of the thyroid hormone receptor (TR) family act on vertebrate development and homeostasis by activating or repressing transcription of specific target genes in a ligand-dependent way. Repression by TR in the absence of ligand is mediated by an active silencing mechanism. The oncogene v-ErbA is a variant form of TR unable to bind hormone and thus acts as a constitutive repressor. Functional studies and mutation analysis revealed that the TR/v-ErbA silencing domain is composed of three silencing subdomains (SSD1-3) which, although nonfunctional individually, synergize such that silencing activity is restored when they are combined in a heteromeric complex. Here we demonstrate, using protein interaction assays in vitro and in vivo, that the inactive v-ErbA point mutant L489R within helix 5/6 in SSD2 fails to interact with the two corepressors N-CoR (nuclear receptor corepressor) or SMRT (silencing mediator of retinoic acid and thyroid hormone receptor). Furthermore, mutants in SSD1 and SSD3 exhibit a reduced corepressor recruitment corresponding to their weak residual silencing activity. In mammalian two-hybrid assays, only the combination of all three silencing subdomains, SSD1-3, leads to a cooperative binding to the corepressors N-CoR or SMRT comparable to that of the full-length v-ErbA repression domain. In conclusion, full silencing activity requires corepressor interaction with all three silencing subdomains, SSD1-3. Among these, SSD2 is a new target for N-CoR and SMRT and is essential for corepressor binding and function. [less ▲]

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See detailFar upstream sequences regulate the human prolactin promoter transcription
Van de Weerdt, Cécile ULg; Peers, Bernard ULg; Belayew, A. et al

in Neuroendocrinology (2000), 71(2), 124-37

The human prolactin gene is mainly expressed in pituitary lactotrope cells, but transcription from an alternative, far upstream promoter was detected in lymphoid, placental and mammary cells. We describe ... [more ▼]

The human prolactin gene is mainly expressed in pituitary lactotrope cells, but transcription from an alternative, far upstream promoter was detected in lymphoid, placental and mammary cells. We describe the transcriptional activity in rat pituitary cells of the complete region separating the two promoters, using transient transfection experiments. A far upstream activating region was only functional in combination with the prolactin promoter. DNaseI protection experiments revealed, in addition to binding sites for the pituitary-specific factor Pit-1, sites (e.g. SD1) for several ubiquitous factors and one lymphoid-specific factor (SD4). A single copy of the ubiquitous site SD1 or the lymphoid-specific site SD4 was unable to activate transcription of a heterologous promoter in pituitary cells. However, SD1 activated transcription in nonpituitary cells and SD4 was functional specifically in lymphoid cells. Five copies of a distal site (D8) activated transcription in each cell type tested. Gel retardation experiments show that this site binds the specific factor C/EBP in liver and a distinct factor in other cell types. Our results suggest that different elements within this large region direct specific expression from each promoter via a complex interplay between cell-specific and ubiquitous transcription factors. [less ▲]

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See detailTranscription factor Pit-1 expression is modulated upon seasonal acclimatization of eurythermal ectotherms: Identification of two Pit-1 genes in the carp
Kausel, Gudrun; Vera, María Inés; San Martin, Rody et al

in Journal of Cellular Biochemistry (1999), 75(4), 598-609

A second Pit-1 gene in carp (Cyprinus carpio), including the complete structural gene and 1.1 kb of promoter region, was identified and completely sequenced. The exon-intron structure was determined, and ... [more ▼]

A second Pit-1 gene in carp (Cyprinus carpio), including the complete structural gene and 1.1 kb of promoter region, was identified and completely sequenced. The exon-intron structure was determined, and reverse transcription-polymerase chain reaction (RT-PCR) experiments suggest that only one Pit-1 splice variant is present in carp pituitary. The effect of seasonal acclimatization on the extent of Pit-1 gene expression was studied in summer- and winter-acclimatized carp. Quantitative RT-PCR analysis revealed a clear increase of Pit-1 mRNA in the pituitaries from summer-acclimatized carp compared with the winter-adapted fish. In situ hybridization of pituitary gland sections with riboprobes representing the complete 5-transactivating region of carp Pit-1 depicted a significantly higher Pit-1 mRNA level in the rostral pars distalis of the summer-acclimatized fish where prolactin is expressed in a manner that resembles the seasonal increase observed in the proximal pars distalis and the pars intermedia. The cell- and temporal-specific transcription of Pit-1 supports its role in the molecular mechanisms that underly the acclimatization process undergone by eurythermal fish as a result of the physical effects of seasonal changes on their habitat. J. Cell. Biochem. 75:598-609, 1999. © 1999 Wiley-Liss, Inc. [less ▲]

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See detailReceptors as screening tools in the detections of hormones. Applications in the control of meat production
Maghuin-Rogister, Guy ULg; Baise, Etienne ULg; Carpeaux, Rudy et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (1999), 4(1), 21-22

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See detailStructure and functional analysis of a tilapia (Oreochromis mossambicus) growth hormone gene: activation and repression by pituitary transcription factor Pit-1
Sekkali, Belaid; Brim, Hassan; Muller, Marc ULg et al

in DNA & Cell Biology (1999), 18(6), 489-502

A gene encoding the Tilapia mossambica (Oreochromis mossambicus) growth hormone (tiGH) was isolated and sequenced. The gene spans 5.6 kb, including 3.7 kb of 5' and 0.2 kb of 3' flanking sequences and a 1 ... [more ▼]

A gene encoding the Tilapia mossambica (Oreochromis mossambicus) growth hormone (tiGH) was isolated and sequenced. The gene spans 5.6 kb, including 3.7 kb of 5' and 0.2 kb of 3' flanking sequences and a 1.7-kb transcription unit comprised of six exons and five introns. The gene and the 5' flanking region contain several potential binding sites for Pit-1, a key transcription activator of mammalian GH genes. One of these (-57/-42) is highly conserved in fish GH genes. It activates transcription in pituitary cells and binds Pit-1. Transfection of luciferase reporter plasmids containing either the -3602/+19 tiGH sequence or one of its 5' deletion mutants (-2863/, -1292/, and -463/+19) resulted in strong activity in Pit-1-producing rat pituitary GC cells. A dose-dependent activation of the tiGH promoter was achieved in nonpituitary fish EPC and monkey COS cells cotransfected with a rat Pit-1 expression vector, demonstrating the crucial role played by Pit-1 as an activator of the tiGH gene. Fusion of the tiGH promoter with the beta-galactosidase gene led to transient expression specifically in the nervous system of microinjected zebrafish embryos. The activity of the tiGH promoter in GC and EPC cells was strongly repressed by extending its 3' end from +19 to +40, a sequence in which a Pit-1-binding site was identified using gel retardation assays. Point mutations of the site that suppressed Pit-1 binding in vitro restored full tiGH promoter activity. Thus, a Pit-1-binding site located in the 5' untranslated region mediates Pit-1-dependent repression of the tiGH gene. [less ▲]

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See detailPit-1 mediates cell-specific and cAMP-induced transcription of the tilapia GH gene
Sekkali, B.; Belayew, A.; Bortolussi, M. et al

in Molecular & Cellular Endocrinology (1999), 152(1-2), 111-23

Expression of the tilapia growth hormone (tiGH) gene is pituitary-specific and controlled by intracellular cAMP levels. DNaseI protection experiments allowed us to identify four Pit-1 binding sites in the ... [more ▼]

Expression of the tilapia growth hormone (tiGH) gene is pituitary-specific and controlled by intracellular cAMP levels. DNaseI protection experiments allowed us to identify four Pit-1 binding sites in the tiGH - 465/ + 19 region. Deletion and mutagenesis analysis revealed that the - 131/+ 19 region, containing two Pit-1 sites, or four copies of the most proximal site tiGHF1 fused to the heterologous Tk promoter, confer high level expression in rat pituitary cells and direct transcription in non-pituitary cells only after expression of rat Pit-1. We show that a tilapia pituitary factor specifically binds to site tiGHF1 and obtained a partial cDNA sequence coding for tilapia Pit-1. The cAMP stimulation is mediated by the proximal (- 131/- 31) promoter region. It is Pit-1-dependent and requires the tiGHF1 site. In addition, four copies of this site confer cAMP inducibility to the Tk promoter in GC cells. [less ▲]

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See detailAPH-1, a POU homeobox gene expressed in the salt gland of the crustacean Artemia franciscana
Chavez, Marcela; Landry, Claire; Loret, Suzanne et al

in Mechanisms of Development (1999), 87(1-2), 207-12

We characterized the first POU-homeoprotein in a crustacean (designated APH-1 for Artemia POU-Homeoprotein, EMBL Y15070). The amino acid sequence of the APH-1 POU-domain is identical, except for two ... [more ▼]

We characterized the first POU-homeoprotein in a crustacean (designated APH-1 for Artemia POU-Homeoprotein, EMBL Y15070). The amino acid sequence of the APH-1 POU-domain is identical, except for two residues, to that of the two class III POU proteins Cf1-a (Drosophila) and POU-M1 (Bombyx mori). Southern blot analysis suggests that crustaceans have only one class III POU gene. RT-PCR and whole-mount in situ hybridization show that APH-1 mRNA is present in larvae specifically in the salt gland, an organ which is involved in osmoregulation, and disappears in the adult. [less ▲]

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See detailFunctional analysis of ZNF85 KRAB zinc finger protein, a member of the highly homologous ZNF91 family
Poncelet, Dominique A.; Bellefroid, Eric J.; Bastiaens, P. V. et al

in DNA & Cell Biology (1998), 17(11), 931-43

We previously identified the ZNF85 (HPF4) KRAB zinc finger gene, a member of the human ZNF91 family. Here, we show that the ZNF85 gene is highly expressed in normal adult testis, in seminomas, and in the ... [more ▼]

We previously identified the ZNF85 (HPF4) KRAB zinc finger gene, a member of the human ZNF91 family. Here, we show that the ZNF85 gene is highly expressed in normal adult testis, in seminomas, and in the NT2/D1 teratocarcinoma cell line. Immunocytochemical localization of a panel of beta-Gal/ZNF85 fusion proteins revealed that ZNF85 contains at least one nuclear localization signal located in the spacer region connecting the KRAB domain with the zinc finger repeats. Bacterially expressed ZNF85 zinc finger domain bound strongly and exclusively to DNA in vitro in a zinc-dependent manner. The KRAB(A) domain of the ZNF85 protein and of several other members of the ZNF91 family exhibited repressing activity when tested in Gal4 fusion protein assays. The repression was significantly enhanced by the addition of the KRAB (B) domain, whereas further addition of other conserved regions had no effect. The ZNF85 KRAB(A) and (B) domains in vitro bound several nuclear proteins that might constitute critical cofactors for repression. [less ▲]

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See detailEffect of seasonal acclimatization on the expression of the carp transcription factor Pit-1
Kausel, G.; Vera, M. I.; Figueroa, J. et al

in Biochemistry and Molecular Biology International (1998), 45(5), 813-21

We isolated a clone comprising four exons of the carp Pit-1 gene. Using synthetic oligonucleotide probes derived from the carp Pit-1 sequence Pit-1 expression was assessed by in situ hybridization in ... [more ▼]

We isolated a clone comprising four exons of the carp Pit-1 gene. Using synthetic oligonucleotide probes derived from the carp Pit-1 sequence Pit-1 expression was assessed by in situ hybridization in pituitary sections from summer- and winter-acclimatized carp. Semiquantitative analyses of the hybridization signals revealed a significant higher Pit-1 expression in the proximal pars distalis (PPD) and pars intermedia (PI) of the pituitary glands from summer-acclimatized carp, compared to the winter-acclimatized fish. In both adaptive states, relative to the PPD and PI, only a basal Pit-1 expression was detected in the rostral pars distalis. Thus, during seasonal acclimatization of an eurythermal fish, Pit-1 seems to be involved in the mechanisms that underlie the compensatory response. [less ▲]

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See detailRégulation transcriptionnelle du gène de la prolactine humaine
Muller, Marc ULg; Berwaer, Monique; Caccavelli, Laure et al

in Medecine Sciences : M/S (1998), 14(580-587),

Le gène humain de la prolactine (hPRL) est exprimé essentiellement par l'antéhypophyse. L'analyse des éléments régulateurs de la transcription sur plus de 5 000 bases en amont du site de début de ... [more ▼]

Le gène humain de la prolactine (hPRL) est exprimé essentiellement par l'antéhypophyse. L'analyse des éléments régulateurs de la transcription sur plus de 5 000 bases en amont du site de début de transcription a montré l'importance du contrôle par le facteur de transcription Pit-1, spécifique de l'hypophyse, à côté de facteurs ubiquistes. Des hormones modulent l'expression du gène hPRL, transmettant leur signal par les voies intracellulaires de l'AMP cyclique et du calcium, relayées au niveau du promoteur proximal (-250/+1) essentiellement par les facteurs de transcription Pit-1 et AP-1. Les récepteurs nucléaires contrôlent aussi en partie la transcription de hPRL: le récepteur des oestrogènes l'active en se liant aux éléments de réponse distaux ; les récepteurs nucléaires des hormones thyroïdiennes et des glucocorticoïdes la répriment en interférant respectivement avec la fonction activatrice de AP-1 et de Pit-1. [less ▲]

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See detailPro239Ser: a novel recessive mutation of the Pit-1 gene in seven Middle Eastern children with growth hormone, prolactin, and thyrotropin deficiency
Pernasetti, Flavia; Milner, Robert DG; al Ashwal, Abdullah A Z et al

in Journal of Clinical Endocrinology and Metabolism (1998), 83(6), 2079-83

Pit-1, a member of the POU-homeo domain protein family, is one of the transcription factors responsible for anterior pituitary development and pituitary-specific gene expression. Here, we describe seven ... [more ▼]

Pit-1, a member of the POU-homeo domain protein family, is one of the transcription factors responsible for anterior pituitary development and pituitary-specific gene expression. Here, we describe seven children with GH, PRL, and TSH deficiency from three, reportedly unrelated, Middle Eastern families, harboring a newly recognized Pro- > Ser recessive mutation in codon 239 of the Pit-1 gene. The mutated residue is located at the beginning of the second alpha-helix of the POU-homeodomain and is strictly conserved among all POU proteins. The Pro239Ser mutant binds DNA normally but is unable to stimulate transcription. [less ▲]

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See detailTranscription factor AP1 is involved in basal and okadaic acid-stimulated activity of the human PRL promoter
Caccavelli, Laure; Manfroid, Isabelle ULg; Martial, Joseph ULg et al

in Molecular Endocrinology (Baltimore, Md.) (1998), 12(8), 1215-27

The tumor promoter, okadaic acid (OA), an inhibitor of protein phosphatases, stimulates the activity of the human PRL (hPRL) proximal promoter. We analyzed in detail the effects of OA on transcription ... [more ▼]

The tumor promoter, okadaic acid (OA), an inhibitor of protein phosphatases, stimulates the activity of the human PRL (hPRL) proximal promoter. We analyzed in detail the effects of OA on transcription factor binding to elements P1 and P2 of this promoter, sequences known to contain at least one Pit-1 binding site each. OA treatment induces binding of an AP1-related transcription factor to the P1 site. This effect is specific, as protein binding to the P2 site is not altered by the treatment. Specific antibodies were used to confirm that the OA-induced complex is related to AP1 and to show that it contains JunD and c-fos, but not Pit-1. The increase in AP1 binding to P1 and to a canonical AP1 site correlates to an increase in cellular JunD and c-fos content. Transient transfection experiments showed that both AP1 and Pit-1 are involved in the regulation of basal and OA-stimulated promoter activity. Our results demonstrate that a member of the AP1 family, containing JunD and c-fos, can bind to the proximal element P1 within the hPRL promoter. In addition, they show that AP1 is involved in both basal and OA-stimulated expression of the hPRL gene. [less ▲]

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See detailAt Least Three Subdomains of V-Erba Are Involved in Its Silencing Function
Busch, Kerstin; Martin, Bernd; Baniahmad, Aria et al

in Molecular Endocrinology (1997), 11(3), 379-89

Several members of the thyroid hormone receptor (TR) family are able to switch from a transcriptional repressor to a transcriptional activator upon binding of their ligand. The oncogene v-erbA is a ... [more ▼]

Several members of the thyroid hormone receptor (TR) family are able to switch from a transcriptional repressor to a transcriptional activator upon binding of their ligand. The oncogene v-erbA is a variant form of the TR unable to bind hormone and thus acts as a constitutive repressor. We demonstrate, using fusion proteins between the DNA-binding domain of the yeast factor GAL4 and the silencing domains of v-erbA and TR beta, that point mutations in three different regions severely affect their repression function. Furthermore, the three regions, each as an inactive fusion protein with the GAL4 DNA-binding domain, restore silencing activity when assembled on the same promoter. These observations define at least three silencing subdomains, SSD1-SSD3, which are involved in the silencing function of v-erbA. We propose a model in which full silencing activity is brought about by the combined interaction of each silencing subdomain with corepressors and/or basal transcription factors. [less ▲]

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See detailRegulation of prolactin gene expression in fishes
Poncelet, A. C.; Yaron, Z.; Levavi-Sivan, B. et al

in Nagabhushanan, R.; Thompson, M.F.; Fingennan, M. (Eds.) Recent Advances in Marine Biotechnology (1997)

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