PMID:12675812
| Citation |
Bordes, P, Conter, A, Morales, V, Bouvier, J, Kolb, A and Gutierrez, C (2003) DNA supercoiling contributes to disconnect sigmaS accumulation from sigmaS-dependent transcription in Escherichia coli. Mol. Microbiol. 48:561-71 |
|---|---|
| Abstract |
The sigmaS subunit of RNA polymerase is a key regulator of Escherichia coli transcription in stress conditions. sigmaS accumulates in cells subjected to stresses such as an osmotic upshift or the entry into stationary phase. We show here that, at elevated osmolarity, sigmaS accumulates long before the beginning of the sigmaS-dependent induction of osmEp, one of its target promoters. A combination of in vivo and in vitro evidence indicates that a high level of DNA negative supercoiling inhibits transcription by EsigmaS. The variations in superhelical densities occurring as a function of growth conditions can modulate transcription of a subset of sigmaS targets and thereby contribute to the temporal disconnection between the accumulation of sigmaS and sigmaS-driven transcription. We propose that, in stress conditions leading to the accumulation of sigmaS without lowering the growth rate, the level of DNA supercoiling acts as a checkpoint that delays the shift from the major (Esigma70) to the general stress (EsigmaS) transcriptional machinery, retarding the induction of a subset of the sigmaS regulon until the conditions become unfavourable enough to cause entry into stationary phase. |
| Links | |
| Keywords |
Bacterial Proteins/metabolism; DNA, Bacterial/chemistry; DNA, Bacterial/metabolism; DNA, Superhelical/chemistry; DNA, Superhelical/metabolism; DNA-Directed RNA Polymerases/metabolism; Enzyme Inhibitors/metabolism; Escherichia coli/drug effects; Escherichia coli/genetics; Escherichia coli/metabolism; Escherichia coli Proteins/genetics; Gene Expression Regulation; Gene Expression Regulation, Bacterial; Genes, Reporter; Membrane Proteins/genetics; Novobiocin/metabolism; Nucleic Acid Conformation; Osmolar Concentration; Plasmids/genetics; Plasmids/metabolism; Promoter Regions, Genetic; Sigma Factor/metabolism; Transcription, Genetic |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.