title: sigmaS, a major player in the response to environmental stresses in Escherichia coli: role, regulation and mechanisms of promoter recognition.
abstract: Bacterial cells often face hostile environmental conditions, to which they adapt by activation of stress responses. In Escherichia coli, environmental stresses resulting in significant reduction in growth rate stimulate the expression of the rpoS gene, encoding the alternative σ factor σ(S). The σ(S) protein associates with RNA polymerase, and through transcription of genes belonging to the rpoS regulon allows the activation of a 'general stress response', which protects the bacterial cell from harmful environmental conditions. Each step of this process is finely tuned in order to cater to the needs of the bacterial cell: in particular, selective promoter recognition by σ(S) is achieved through small deviations from a common consensus DNA sequence for both σ(S) and the housekeeping σ(70). Recognition of specific DNA elements by σ(S) is integrated with the effects of environmental signals and the interaction with regulatory proteins, in what represents a fascinating example of multifactorial regulation of gene expression. In this report, we discuss the function of the rpoS gene in the general stress response, and review the current knowledge on regulation of rpoS expression and on promoter recognition by σ(S).
authors.affiliation: Department of Biosciences, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Landini
authors.forename: Thomas
authors.initials: T
authors.lastname: Egli
authors.forename: Johannes
authors.initials: J
authors.lastname: Wolf
authors.forename: Stephan
authors.initials: S
authors.lastname: Lacour
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D017753:Ecosystem; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria