title: Small non-coding RNAs, co-ordinators of adaptation processes in Escherichia coli: the RpoS paradigm.
abstract: Adaptation to the changing environment requires both the integration of external signals and the co-ordination of internal responses. Around 50 non-coding small RNAs (sRNAs) have been described in Escherichia coli; the levels of many of these vary with changing environmental conditions. This suggests that they play a role in cell adaptation. In this review, we use the regulation of RpoS (sigma38) translation as a paradigm of sRNA-mediated response to environmental conditions; rpoS is currently the only known gene regulated post-transcriptionally by at least three sRNAs. DsrA and RprA stimulate RpoS translation in response to low temperature and cell surface stress, respectively, whereas OxyS represses RpoS translation in response to oxidative shock. However, in addition to regulating RpoS translation, DsrA represses the translation of HNS (a global regulator of gene expression), whereas OxyS represses the translation of FhlA (a transcriptional activator), allowing the cell to co-ordinate different pathways involved in cell adaptation. Environmental cues affect the synthesis and stability of specific sRNAs, resulting in specific sRNA-dependent translational control.
authors.affiliation: UMR960 INRA - ENVT, Laboratoire de Microbiologie Moléculaire, 23 Chemin des Capelles, 31076 Toulouse Cedex, France.
authors.forename: F
authors.initials: F
authors.lastname: Repoila
authors.forename: N
authors.initials: N
authors.lastname: Majdalani
authors.forename: S
authors.initials: S
authors.lastname: Gottesman
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D014176:Protein Biosynthesis; D020871:RNA Stability; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D058727:RNA, Small Untranslated; D022661:RNA, Untranslated / Q000502:physiology; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C405431:DsrA RNA, E coli; D012329:RNA, Bacterial; D058727:RNA, Small Untranslated; D022661:RNA, Untranslated; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria