title: The small noncoding DsrA RNA is an acid resistance regulator in Escherichia coli.
abstract: DsrA RNA is a small (87-nucleotide) regulatory RNA of Escherichia coli that acts by RNA-RNA interactions to control translation and turnover of specific mRNAs. Two targets of DsrA regulation are RpoS, the stationary-phase and stress response sigma factor (sigmas), and H-NS, a histone-like nucleoid protein and global transcription repressor. Genes regulated globally by RpoS and H-NS include stress response proteins and virulence factors for pathogenic E. coli. Here, by using transcription profiling via DNA arrays, we have identified genes induced by DsrA. Steady-state levels of mRNAs from many genes increased with DsrA overproduction, including multiple acid resistance genes of E. coli. Quantitative primer extension analysis verified the induction of individual acid resistance genes in the hdeAB, gadAX, and gadBC operons. E. coli K-12 strains, as well as pathogenic E. coli O157:H7, exhibited compromised acid resistance in dsrA mutants. Conversely, overproduction of DsrA from a plasmid rendered the acid-sensitive dsrA mutant extremely acid resistant. Thus, DsrA RNA plays a regulatory role in acid resistance. Whether DsrA targets acid resistance genes directly by base pairing or indirectly via perturbation of RpoS and/or H-NS is not known, but in either event, our results suggest that DsrA RNA may enhance the virulence of pathogenic E. coli.
authors.affiliation: Wadsworth Center, New York State Department of Health, Center for Medical Sciences, Albany, New York, USA. ral@jhu.edu
authors.forename: Richard A
authors.initials: RA
authors.lastname: Lease
authors.forename: Dorie
authors.initials: D
authors.lastname: Smith
authors.forename: Kathleen
authors.initials: K
authors.lastname: McDonough
authors.forename: Marlene
authors.initials: M
authors.lastname: Belfort
mesh_terms: D000143:Acids / Q000494:pharmacology*; D000222:Adaptation, Physiological; D051777:AraC Transcription Factor / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D019453:Escherichia coli O157 / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000502:physiology; D006131:Growth Inhibitors / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D009876:Operon; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D058727:RNA, Small Untranslated; D022661:RNA, Untranslated / Q000235:genetics* / Q000502:physiology*; D018085:Regulon
chemical_list: D000143:Acids; D051777:AraC Transcription Factor; D001426:Bacterial Proteins; C405431:DsrA RNA, E coli; D029968:Escherichia coli Proteins; C491226:GadC protein, E coli; C103589:GadC protein, bacteria; C446316:GadX protein, E coli; D006131:Growth Inhibitors; D008565:Membrane Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D058727:RNA, Small Untranslated; D022661:RNA, Untranslated; C084501:hdeA protein, E coli; C084502:hdeB protein, E coli; C121044:gadA protein, E coli; D005968:Glutamate Decarboxylase