References of "Muller, Marc"
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See detailCooperative interaction of chicken lysozyme enhancer sub-domains partially overlapping with a steroid receptor binding site.
Altschmied, J.; Muller, Marc ULg; Baniahmad, A. et al

in Nucleic Acids Research (1989), 17(13), 4975-91

Expression of the lysozyme gene is a marker for the differentiation of macrophages, lysozyme transcription being gradually increased during maturation. We have analyzed the fine structure and function of ... [more ▼]

Expression of the lysozyme gene is a marker for the differentiation of macrophages, lysozyme transcription being gradually increased during maturation. We have analyzed the fine structure and function of two macrophage-specific enhancer elements of the chicken lysozyme gene (E-2.7 kb and E-0.2 kb). Both increase their activities upon LPS induction, both contain multiple binding sites for similar or identical nuclear factors and both can be divided into two functional modules. For the E-0.2 kb enhancer we found a synergistic activity of the modules to be dependent on their distance. Binding sites for nuclear proteins within enhancer E-0.2 kb overlap substantially with the previously identified progesterone/glucocorticoid receptor binding site, which is required for steroid induction of lysozyme transcription in the oviduct. [less ▲]

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See detailPairing Properties of Bromouracil and Repair of Bromouracil-Containing DNA. Possible Utilization of Bromodeoxyuridine Triphosphate for Site-Directed Mutagenesis
Muller, Marc ULg; Martial, Joseph ULg; Verly, W. G.

in Biochemical Journal (1988), 253(3), 637-643

5-Bromo-2'-deoxyuridine triphosphate (Br-dUTP) and dTTP are used interchangeably for DNA synthesis in vitro by the Klenow fragment of Escherichia coli DNA polymerase I. When DNA containing Br-dUMP instead ... [more ▼]

5-Bromo-2'-deoxyuridine triphosphate (Br-dUTP) and dTTP are used interchangeably for DNA synthesis in vitro by the Klenow fragment of Escherichia coli DNA polymerase I. When DNA containing Br-dUMP instead of dTMP at a few preselected sites is transfected into competent bacteria, no mutation occurs, indicating that in vivo E. coli DNA polymerase always places a dAMP residue in front of any unrepaired Br-dUMP residue. On the other hand, in vitro Br-dUTP can also replace dCTP, but only with difficulty: when dCTP is absent, Br-dUMP can be forced in front of a dGMP residue, but the Klenow polymerase pauses before and after addition of Br-dUMP. Transfection into E. coli of the substituted DNA leads to the expected G----A transitions. These mutations can easily be targeted by using a suitable primer and the correctly chosen mix of deoxynucleoside triphosphates containing Br-dUTP. When Br-dUMP has been placed in front of a dGMP residue, the mutation yield is not 100%, showing a partial repair of the transfected DNA before it is replicated. Advantage can be taken of this partial repair to prepare a set of different mutations within a target region in a single experiment. [less ▲]

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See detailMany transcription factors interact synergistically with steroid receptors.
Schule, Roland; Muller, Marc ULg; Kaltschmidt, Christian et al

in Science (1988), 242(4884), 1418-20

Progesterone (PRE) or glucocorticoid receptor (GRE) DNA binding sites are often found clustered with binding sites for other transcription factors. Individual protein binding sites were tested without the ... [more ▼]

Progesterone (PRE) or glucocorticoid receptor (GRE) DNA binding sites are often found clustered with binding sites for other transcription factors. Individual protein binding sites were tested without the influence of adjacent factors by analyzing isolated combinations of several transcription factor binding sites with PREs or GREs. All show strong synergistic effects on steroid induction. The degree of synergism is inversely related to the strength of the GRE. Thus, a steroid responsive unit can be composed of several modules that, if positioned correctly, act synergistically. [less ▲]

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See detailCooperativity of the glucocorticoid receptor and the CACCC-box binding factor.
Schule, Roland; Muller, Marc ULg; Otsuka-Murakami, Hidetsuka et al

in Nature (1988), 332(6159), 87-90

Glucocorticoid receptor binding sites (GRE) are often tightly clustered with other transcription factor binding sequences. Examples of this occur upstream of the genes for chicken lysozyme and human ... [more ▼]

Glucocorticoid receptor binding sites (GRE) are often tightly clustered with other transcription factor binding sequences. Examples of this occur upstream of the genes for chicken lysozyme and human metallothionein IIA (ref. 3), in several retroviral LTRs and upstream of the rat tryptophan oxygenase (TO) gene. In the TO gene, sequences immediately upstream of a glucocorticoid receptor binding site are required for steroid induction and contain a CACCC-box identical to that found in the beta globin gene. Here we demonstrate specific binding to this TO-CACCC element and show that it will also act cooperatively with a MMTV glucocorticoid receptor binding site. The response to dexamethasone is independent of the order and relative orientation of these elements but does depend on their precise spacing. Optimal induction occurs at a periodicity of approximately 10 base pairs (bp) indicating a requirement for stereospecific alignment. Binding to the CACCC box, however, is not affected by its distance from the glucocorticoid receptor site. We conclude that the observed cooperativity is mediated by protein:protein interactions and does not depend on cooperative DNA binding. [less ▲]

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See detailActivity of two different silencer elements of the chicken lysozyme gene can be compensated by enhancer elements.
Baniahmad, A.; Muller, Marc ULg; Steiner, C. et al

in EMBO Journal (1987), 6(8), 2297-303

The chicken lysozyme gene is constitutively expressed in macrophages. Transfection of recombinant genes containing different portions of the lysozyme 5' upstream region revealed the existence of two ... [more ▼]

The chicken lysozyme gene is constitutively expressed in macrophages. Transfection of recombinant genes containing different portions of the lysozyme 5' upstream region revealed the existence of two negative transcriptional elements within 1 kb upstream of the start sites. Both elements placed upstream or downstream of a heterologous promoter-gene unit repress transcription independent of their orientation and are therefore called silencer elements, although their repressing activities 3' of the gene are reduced. One silencer (N-1.0 kb) at position -1 kb consists of the central region of the chicken middle repetitive sequence element CR1 and can be divided into two functional domains. N-1.0 kb is active in all cell types tested. The other silencer (N-0.25 kb) at position -0.25 kb shows reduced activity in primary macrophages. Despite their different specificities, the activity of both silencer elements can be influenced similarly. An inverse linear relationship between the transcriptional activity of the tested constructs and the potential inhibition by the silencer elements was found: weak transcription units can be strongly repressed, whereas strong transcription units can be only weakly repressed. Such a mechanism may help to turn off completely a particular gene in situations or tissues where strong positive regulators are inactive. [less ▲]

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See detailLysozyme gene activity in chicken macrophages is controlled by positive and negative regulatory elements.
Steiner, Christoph; Muller, Marc ULg; Baniahmad, Aria et al

in Nucleic Acids Research (1987), 15(10), 4163-78

The chicken lysozyme gene is constitutively active in macrophages and under the control of steroid hormones in the oviduct. To investigate which DNA elements are involved in the control of its expression ... [more ▼]

The chicken lysozyme gene is constitutively active in macrophages and under the control of steroid hormones in the oviduct. To investigate which DNA elements are involved in the control of its expression in macrophages we performed transient DNA transfer experiments with two different types of plasmids: 5'-deletion mutants of the upstream region of the chicken lysozyme gene and different fragments from this area in front of the thymidine kinase promoter (herpes simplex virus), each placed in front of the CAT (chloramphenicol acetyl transferase) coding sequence. Two enhancers (E-2.7 kb and E-0.2 kb) were characterized. They are active in macrophages, but not in chicken fibroblasts. Furthermore a negative element (N-2.4 kb) was identified, which is active in fibroblasts and promyelocytes, but not in mature macrophages. The combined action of all three elements contributes to the observed lysozyme gene activities: no activity in fibroblasts, moderate activity in promyelocytes and high activity in mature macrophages. [less ▲]

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See detailFidelité de la réparation de l'ADN
Muller, Marc ULg

Doctoral thesis (1986)

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See detailDifferential implication of deoxyribonucleic acid methylation in rat prolactin and rat growth hormone gene expressions: a comparison between rat pituitary cell strains
Laverriere, Jean-Noël; Muller, Marc ULg; Buisson, Nicole et al

in Endocrinology (1986), 118(1), 198-206

In order to assess the potential role of DNA methylation in the expression of rat PRL (rPRL) as compared to rat GH (rGH) gene, the cleavage patterns generated by the isoschizomeric restriction enzymes ... [more ▼]

In order to assess the potential role of DNA methylation in the expression of rat PRL (rPRL) as compared to rat GH (rGH) gene, the cleavage patterns generated by the isoschizomeric restriction enzymes HpaII and MspI were examined in DNA isolated from rat pituitary cell lines producing either high levels of rPRL (GH3B6) or of rGH (GC) and in a stable variant cell strain which produces minute amounts of both hormones (GH3CDL cells). The rPRL and the rGH genes were found hypomethylated in GH3B6 and GC cells, respectively, whereas in GH3CDL cells both genes were methylated, indicating a correlation between the extent of gene methylation and the level of expression. However the use of 5-azacytidine (5-azaC), which decreases DNA methylation, suggested a variable importance of gene methylation in the control of rPRL and rGH gene expression. 5-AzaC was unable to increase rPRL production to a detectable level in GC cells, whereas the cytidine analog markedly increased rPRL production and rGH production in GH3CDL cells. Further analysis using GH3CDL cells showed that the extent of the 5-azaC-induced rPRL and rGH gene demethylation was consistent with the 5-azaC-induced increase of gene expressions. However, in these cells, the stimulation of rPRL and rGH production unexpectedly increased as a function of time elapsed after drug withdrawal. The maximal stimulation, 30-fold and 7-fold, respectively, was observed 3 weeks after a 60-h exposure to 5-azaC. This pattern suggests that other events are required for the full expression of rPRL and rGH genes in addition to their own demethylation. [less ▲]

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See detailRégulations de l'expression des gênes de la prolactine et de l'hormone de croissance dans des cellules hypophysaires en culture
Laverriere, J. N.; Tixier-Vidal, A.; Morin, Alexis ULg et al

in Annales d'Endocrinologie (1986), 47(1), 22-7

The rat pituitary tumor derived cell lines of the "GH" family offer a fruitful model for studying the expressions of the prolactin (rPRL) and growth hormone (rGH) genes in basic and regulated states. In ... [more ▼]

The rat pituitary tumor derived cell lines of the "GH" family offer a fruitful model for studying the expressions of the prolactin (rPRL) and growth hormone (rGH) genes in basic and regulated states. In order to assess the potential role of DNA methylation in the basic expressions of rPRL and rGH genes we have used different cell strains which produce either high level of rPRL (GH3B6 cells) or of rGH (GC cells) and minute amounts of both hormones (GH3CDL cells). The cleavage patterns generated by the methylation sensitive enzymes Hpa II and Msp I indicated an inverse correlation between the extent of gene methylation and the level of expression. However the use of 5-azacytidine which decreases DNA methylation suggested a variable importance of gene methylation in the respective control of rPRL and rGH genes depending on the cell lines. In an other hand we attempted to elucidate some of the mechanisms by which thyroliberin (TRH) enhances rPRL gene transcription in GH3B6 cells. Preliminary results indicated that the persistent occupancy of the TRH receptors was required to sustain at least for the first 5 hours the increased rate of rPRL gene transcription. In addition the possible relationship between the TRH-induced acute rPRL release and the stimulation of rPRL gene transcription was investigated. The results suggested that the activators of the C kinase-mediated pathway which are actually involved in the stimulation of the acute release were not sufficient alone for eliciting the maximum TRH response at the gene level. [less ▲]

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See detailDNA methylation and expression of prolactin and growth hormone genes in a rat pituitary strain selected on steroid-depleted medium
Laverriere, J. N.; Muller, Marc ULg; Tougard, C. et al

in MacLeod, R. M.; Thorner, M. O.; Scapagnini, U. (Eds.) Prolactin, basic and clinical correlates (1985)

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See detailLocalisation of the phosphoester bond hydrolyzed by the major apurinic/apyrimidinic endodeoxyribonuclease from rat-liver chromatin.
Verly, Walter G; Colson, Pierre ULg; Zocchi, Germaine ULg et al

in European Journal of Biochemistry (1981), 118

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