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Mechanisms of nitrogen catabolite repression-sensitive gene regulation by the GATA transcription factors in Saccharomyces cerevisiae / Etude des mécanismes par lesquels les facteurs GATA régulent l'expression des gènes soumis à la répression catabolique azotée chez Saccharomyces cerevisiae

The process of specific gene transcription by RNA polymerase II (Pol II) is initiated by the<p>binding of specific transcription factors to DNA. A global understanding of the mechanisms of gene<p>transcriptional regulation of Saccharomyces cerevisiae goes through the description of the targets and<p>the behavior of those transcription factors.<p>The GATA factors are specific transcription factors intervening in the regulation of Nitrogen<p>Catabolite Repression (NCR)-sensitive genes, a mechanism encompassing the transcriptional<p>regulations leading to the preferential use of good nitrogen sources of the growth medium of yeast in<p>the presence of less good nitrogen sources. Those 4 GATA factors involved in NCR comprise 2<p>activators (Gat1 and Gln3) and 2 repressors (Gzf3 and Dal80).<p>Generally speaking, the promoters of genes have always been described like the main place for<p>the integration of the transcription regulation signals relayed by the general and specific transcription<p>factors and the chromatin remodeling factors. Furthermore, the GATA factors have been described as<p>integrating the external signals of nitrogen availability thanks to their specific DNA binding to<p>consensus GATA sequences in the promoter of NCR-sensitive genes. The results presented here<p>introduce many nuances to the model, notably implying new proteins but also new regions in the<p>regulation process of the NCR-sensitive gene regulation. Indeed, the first goal of this work is to<p>discover and understand the mechanisms of NCR-sensitive gene regulation that will explain the<p>variations in their expression levels in the presence of various nitrogen sources and their dependency<p>towards the GATA factors.<p>Strikingly, it appeared that GATA factor positioning was not limited to the promoter, but<p>occurred also in the transcribed region. It seems that the transcription factors may have been driven<p>by the general transcription machinery (Pol II). The binding of a chromatin remodeling complex, RSC,<p>has also been demonstrated in the coding region of NCR-sensitive genes. Moreover, the binding of the<p>histone acetyltransferase complex, SAGA, recruited by the GATA activators, was highlighted along<p>NCR-sensitive genes. The SAGA complex was also implied in their transcriptional regulation.<p>Finally, a ChIP-sequencing experiment revealed an unsuspected number and diversification of<p>targets of the GATA factors in yeast, which were not limited to NCR-sensitive genes.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Identiferoai:union.ndltd.org:ulb.ac.be/oai:dipot.ulb.ac.be:2013/209169
Date19 December 2014
CreatorsRonsmans, Aria
ContributorsDubois, Evelyne, Droogmans, Louis, Georis, Isabelle, Vanhamme, Luc, Marini, Anna Maria, Helmlinger, Dominique, André, Bruno, Lafontaine, Denis, Hermand, Damien
PublisherUniversite Libre de Bruxelles, Université libre de Bruxelles, Faculté des Sciences – Sciences biologiques, Bruxelles
Source SetsUniversité libre de Bruxelles
LanguageEnglish
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/doctoralThesis, info:ulb-repo/semantics/doctoralThesis, info:ulb-repo/semantics/openurl/vlink-dissertation
Format1 v., No full-text files

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