title: Characterization of the role of ribonucleases in Salmonella small RNA decay.
abstract: In pathogenic bacteria, a large number of sRNAs coordinate adaptation to stress and expression of virulence genes. To better understand the turnover of regulatory sRNAs in the model pathogen, Salmonella typhimurium, we have constructed mutants for several ribonucleases (RNase E, RNase G, RNase III, PNPase) and Poly(A) Polymerase I. The expression profiles of four sRNAs conserved among many enterobacteria, CsrB, CsrC, MicA and SraL, were analysed and the processing and stability of these sRNAs was studied in the constructed strains. The degradosome was a common feature involved in the turnover of these four sRNAs. PAPI-mediated polyadenylation was the major factor governing SraL degradation. RNase III was revealed to strongly affect MicA decay. PNPase was shown to be important in the decay of these four sRNAs. The stability of CsrB and CsrC seemed to be independent of the RNA chaperone, Hfq, whereas the decay of SraL and MicA was Hfq-dependent. Taken together, the results of this study provide initial insight into the mechanisms of sRNA decay in Salmonella, and indicate specific contributions of the RNA decay machinery components to the turnover of individual sRNAs.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal.
authors.forename: Sandra C
authors.initials: SC
authors.lastname: Viegas
authors.forename: Verena
authors.initials: V
authors.lastname: Pfeiffer
authors.forename: Alexandra
authors.initials: A
authors.lastname: Sittka
authors.forename: Inês J
authors.initials: IJ
authors.lastname: Silva
authors.forename: Jörg
authors.initials: J
authors.lastname: Vogel
authors.forename: Cecília M
authors.initials: CM
authors.lastname: Arraiano
mesh_terms: D004722:Endoribonucleases / Q000235:genetics / Q000502:physiology; D005095:Exoribonucleases / Q000235:genetics / Q000502:physiology; D009154:Mutation; D026723:Polyadenylation; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics / Q000502:physiology; D020871:RNA Stability; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D022661:RNA, Untranslated / Q000737:chemistry / Q000378:metabolism*; D043244:Ribonuclease III / Q000235:genetics / Q000502:physiology; D012260:Ribonucleases / Q000502:physiology*; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
chemical_list: D012329:RNA, Bacterial; D022661:RNA, Untranslated; D011062:Polynucleotide Adenylyltransferase; D004722:Endoribonucleases; D005095:Exoribonucleases; D012260:Ribonucleases; D043244:Ribonuclease III; C022537:ribonuclease E