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2015-01-13 - Article/Dans un journal avec peer-review - Anglais - 13 page(s)

Lévi-Meyrueis Corinne, Monteil Véronique, Sismeiro Odile, Dillies Marie-Agnès, Kolb Annie, Monot Marc, Dupuy Bruno, Serradas Duarte Sara, Jagla Bernd, Coppée Jean-Yves, Beraud Mélanie , Norel Françoise, "Repressor activity of the RpoS/SigmaS-dependent RNA polymerase requires DNA binding" in Nucleic Acids Research

  • Edition : Oxford University Press, Oxford (United Kingdom)
  • Codes CREF : Biochimie (DI3112), Biologie moléculaire (DI3111)

Abstract(s) :

(Anglais) The RpoS/sigmaS sigma subunit of RNA polymerase (RNAP) activates transcription of stationary phase genes in many Gram-negative bacteria and controls adaptive functions, including stress resistance, biofilm formation and virulence. In this study, we address an important but poorly understood aspect of sigmaS-dependent control, that of a repressor. Negative regulation by sigmaS has been proposed to result largely from competition between sigmaS and other sigma factors for binding to a limited amount of core RNAP (E). To assess whether sigmaS binding to E alone results in significant downregulation of gene expression by other sigma factors, we characterized an rpoS mutant of Salmonella enterica serovar Typhimurium producing a sigmaS protein proficient for E-sigmaS complex formation but deficient in promoter DNA binding. Genome expression profiling and physiological assays revealed that this mutant was defective for negative regulation, indicating that gene repression by sigmaS requires its binding to DNA. Although the mechanisms of repression by sigmaS are likely specific to individual genes and environmental conditions, the study of transcription downregulation of the succinate dehydrogenase operon suggests that sigma competition at the promoter DNA level plays an important role in gene repression by E-sigmaS.

Identifiants :
  • DOI : 10.1093/nar/gku1379

Mots-clés :
  • (Anglais) Transcriptional regulation
  • (Anglais) Sigma factor
  • (Anglais) RNA Polymerase
  • (Anglais) Salmonella enterica serovar typhimurium