title: CspC regulates rpoS transcript levels and complements hfq deletions.
abstract: The general stress response in Escherichia coli is activated by several stress agents, including entering the stationary growth phase. This response constitutes a complex regulatory network in which a large number of genes are induced and others are repressed. The stress response is regulated by the alternative sigma factor σ(S) encoded by the rpoS gene. The rpoS transcripts are substrates of the RNA binding protein, Hfq, which is essential for its translation. The rpoS mRNA is also a substrate of the cold shock protein C (CspC) which stabilizes the transcripts. Here we demonstrate, using pull-down assays, that CspC interacts with Hfq via mRNA molecules. We also show that CspC acts on the 5' UTR of the rpoS transcript, but its activity on rpoS is independent of Hfq. Moreover, we show that CspC suppresses the phenotypes of an hfq deletion. These results elucidate a new aspect in the post-transcriptional regulation of the stress response and will further our understanding of this complex network.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Ifat
authors.initials: I
authors.lastname: Cohen-Or
authors.forename: Yotam
authors.initials: Y
authors.lastname: Shenhar
authors.forename: Dvora
authors.initials: D
authors.lastname: Biran
authors.forename: Eliora Z
authors.initials: EZ
authors.lastname: Ron
mesh_terms: D020121:5' Untranslated Regions; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D048168:Escherichia coli K12 / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D035001:Host Factor 1 Protein / Q000235:genetics* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D018384:Oxidative Stress; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological; D015533:Transcriptional Activation
chemical_list: D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C087373:Hfq protein, E coli; D035001:Host Factor 1 Protein; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012808:Sigma Factor; C490241:cspC protein, E coli; C069567:sigma factor KatF protein, Bacteria