title: Turn-over of the small non-coding RNA RprA in E. coli is influenced by osmolarity.
abstract: The sRNA RprA is known to activate rpoS translation in E. coli in an osmolarity-dependent manner. We asked whether RprA stability contributes to osmolarity-dependent regulation and how the RNA binding protein Hfq and the major E. coli endonucleases contribute to this turn-over. The study reveals that osmolarity-dependent turn-over of RprA indeed contributes to its osmolarity-dependent abundance. RprA is stabilized by the RNA chaperone Hfq and in absence of Hfq its turn-over is no longer osmolarity-dependent. The stability of the RprA target mRNA rpoS shows a lower extent of osmolarity dependence, which differs from the profile observed for RprA. Thus, the effect of sucrose is specific for individual RNAs. We can attribute a role of the endoribonuclease RNase E in turn-over of RprA and an indirect effect of the endoribonuclease III in vivo. In addition, RprA is stabilized by the presence of rpoS suggesting that hybrid formation with its target may protect it against ribonucleases. In vitro RprA is cleaved by the RNase E containing degradosome and by RNase III and rpoS interferes with RNase III cleavage. We also show that temperature affects the stabilities of the sRNAs binding to rpoS and of rpoS mRNA itself differentially and that higher stability of DsrA with decreasing temperature may contribute to its high abundance at lower temperatures. This study demonstrates that environmental parameters can affect the stability of sRNAs and consequently their abundance.
authors: Institut für Mikrobiologie und Molekularbiologie, University of Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
authors: Ramakanth
authors: R
authors: Madhugiri
authors: Sobha Rani
authors: SR
authors: Basineni
authors: Gabriele
authors: G
authors: Klug
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics; D004722:Endoribonucleases / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D006207:Half-Life; D035001:Host Factor 1 Protein / Q000235:genetics; D009994:Osmolar Concentration; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics; D043244:Ribonuclease III / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D058727:RNA, Small Untranslated
chemical_list: D000255:Adenosine Triphosphate; D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D004722:Endoribonucleases; D029968:Escherichia coli Proteins; D035001:Host Factor 1 Protein; D012329:RNA, Bacterial; D012333:RNA, Messenger; D022661:RNA, Untranslated; D012097:Repressor Proteins; D043244:Ribonuclease III; D012808:Sigma Factor; C087373:Hfq protein, E coli; C499686:oxyS small RNA, E coli; D058727:RNA, Small Untranslated; C069567:sigma factor KatF protein, Bacteria; C022537:ribonuclease E