title: Translational activation by the noncoding RNA DsrA involves alternative RNase III processing in the rpoS 5'-leader.
abstract: The intricate regulation of the Escherichia coli rpoS gene, which encodes the stationary phase sigma-factor sigmaS, includes translational activation by the noncoding RNA DsrA. We observed that the stability of rpoS mRNA, and concomitantly the concentration of sigmaS, were significantly higher in an RNase III-deficient mutant. As no decay intermediates corresponding to the in vitro mapped RNase III cleavage site in the rpoS leader could be detected in vivo, the initial RNase III cleavage appears to be decisive for the observed rapid inactivation of rpoS mRNA. In contrast, we show that base-pairing of DsrA with the rpoS leader creates an alternative RNase III cleavage site within the rpoS/DsrA duplex. This study provides new insights into regulation by small regulatory RNAs in that the molecular function of DsrA not only facilitates ribosome loading on rpoS mRNA, but additionally involves an alternative processing of the target.
authors.affiliation: Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University Departments at the Vienna Biocenter, A-1030 Vienna, Austria.
authors.forename: Armin
authors.initials: A
authors.lastname: Resch
authors.forename: Taras
authors.initials: T
authors.lastname: Afonyushkin
authors.forename: Tania B
authors.initials: TB
authors.lastname: Lombo
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: McDowall
authors.forename: Udo
authors.initials: U
authors.lastname: Bläsi
authors.forename: Vladimir R
authors.initials: VR
authors.lastname: Kaberdin
mesh_terms: D017398:Alternative Splicing; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D012323:RNA Processing, Post-Transcriptional; D020871:RNA Stability; D012329:RNA, Bacterial / Q000235:genetics* / Q000378:metabolism*; D058727:RNA, Small Untranslated; D022661:RNA, Untranslated / Q000235:genetics* / Q000378:metabolism*; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; C405431:DsrA RNA, E coli; D012329:RNA, Bacterial; D058727:RNA, Small Untranslated; D022661:RNA, Untranslated; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D043244:Ribonuclease III