Doan, Thierry (2003) Etude fonctionnelle du génome de Bacillus subtilis : de nouvelles régulations transcriptionnelles du métabolisme central du carbone. PhD thesis Génétique, Biologie, INAPG.
Abstract
In Bacillus subtilis, the transcription of the gapA operon, including the genes of the central part of glycolysis, is stimulated during growth on glycolytic carbon sources. Our in vivo and in vitro studies of CggR, the repressor that controls this stimulation, have demonstrated on one hand that it is able to bind a long single DNA sequence made of two directly repeated motifs (CGGGACN6TGTCN4CGGGACN6TGTC) and located between the promoter and the translation codon of the cggr-gapA operon and on the other hand that its activity is modulated by fructose-1,6-bisphosphate. Sequence analysis and array hybridization indicated that CggR, which is highly conserved in Gram positive bacteria and defines a subfamily of the SorC/DeoR family of transcriptional regulators, is dedicated to the control of the glycolytic genes. A collaboration with structural biologists (CBS, Montpellier) has been engaged to further study this prototype of a not well known sub-family of transcriptional regulators.
Two groups of paralogous genes have been detected on Bacillus subtilis chromosome
(ywkA et malS, ytsJ and mleA) which products are homologous to malic enzymes. Global transcriptome analysis of a wild-type strain in response to growth in the presence of glucose or malate as sole carbon source has revealed that ywkA expression is induced in the presence of malate. Our experiments have demonstrated that ywkA encodes a NAD-dependent malic enzyme and that its expression is specifically induced by malate and is not subjected to carbon catabolite repression. Moreover, the YufL/YufM two component system has been demonstrated to directly activate ywkA transcription in response to the presence of malate.
However, YwkA is not required for efficient growth on malate as sole carbon source.
Actually, transcriptome study using macroarray technique is available for our laboratory. Hence, we have started the global comparison of genes expression profile in response to different carbon sources.
| Item Type: | PhD Thesis (PhD) |
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| Thesis Supervisor: | Aymerich, Stéphane |
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| Date: | April 2003 |
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| Board of examiners: | Gaillardin, Claude and Glaser, Philippe and Stulke, Jorg and Barras, Frédéric |
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| Ecole Doctorale: | ED 435 AGRICULTURE, ALIMENTATION, BIOLOGIE, ENVIRONNEMENTS ET SANTE |
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| Discipline: | Génétique |
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| Collection (Fonds): | INAPG |
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| Institution: | INAPG |
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| Department: | Biologie |
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| Subjects: | 7. Life Sciences and Engineering |
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| Uncontrolled Keywords: | Bacillus subtilis, Transcription repression, Activation, Carbon metabolism, Glycolysis, Krebs cycle, Pentoses phosphate pathway, Transcriptome analysis, CggR, Fructose- 1, 6-Bisphosphate, Malic enzyme, ywkA., Bacillus subtilis, Répression, Activation de la transcription, Métabolisme carboné, Glycolyse, cycle de Krebs, Voie des pentoses-phosphate, Analyse transcriptomique, CggR, Fructose-1, 6-Biphosphate, Enzyme malique, ywkA. |
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