title: Small noncoding RNA GcvB is a novel regulator of acid resistance in Escherichia coli.
abstract: BACKGROUND
  The low pH environment of the human stomach is lethal for most microorganisms; but not Escherichia coli, which can tolerate extreme acid stress. Acid resistance in E. coli is hierarchically controlled by numerous regulators among which are small noncoding RNAs (sncRNA).
  
  
  RESULTS
  In this study, we individually deleted seventy-nine sncRNA genes from the E. coli K12-MG1655 chromosome, and established a single-sncRNA gene knockout library. By systematically screening the sncRNA mutant library, we show that the sncRNA GcvB is a novel regulator of acid resistance in E. coli. We demonstrate that GcvB enhances the ability of E. coli to survive low pH by upregulating the levels of the alternate sigma factor RpoS.
  
  
  CONCLUSIONS
  GcvB positively regulates acid resistance by affecting RpoS expression. These data advance our understanding of the sncRNA regulatory network involved in modulating acid resistance in E. coli.
authors.affiliation: Department of Biochemistry, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pok Fu Lam, Hong Kong SAR, PR China. yejin@hkucc.hku.hk
authors.forename: Ye
authors.initials: Y
authors.lastname: Jin
authors.forename: Rory M
authors.initials: RM
authors.lastname: Watt
authors.forename: Antoine
authors.initials: A
authors.lastname: Danchin
authors.forename: Jian-dong
authors.initials: JD
authors.lastname: Huang
mesh_terms: D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D006863:Hydrogen-Ion Concentration; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C499290:OppA protein, E coli; D022661:RNA, Untranslated; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria