title: Defining a role for Hfq in Gram-positive bacteria: evidence for Hfq-dependent antisense regulation in Listeria monocytogenes.
abstract: Small trans-encoded RNAs (sRNAs) modulate the translation and decay of mRNAs in bacteria. In Gram-negative species, antisense regulation by trans-encoded sRNAs relies on the Sm-like protein Hfq. In contrast to this, Hfq is dispensable for sRNA-mediated riboregulation in the Gram-positive species studied thus far. Here, we provide evidence for Hfq-dependent translational repression in the Gram-positive human pathogen Listeria monocytogenes, which is known to encode at least 50 sRNAs. We show that the Hfq-binding sRNA LhrA controls the translation and degradation of its target mRNA by an antisense mechanism, and that Hfq facilitates the binding of LhrA to its target. The work presented here provides the first experimental evidence for Hfq-dependent riboregulation in a Gram-positive bacterium. Our findings indicate that modulation of translation by trans-encoded sRNAs may occur by both Hfq-dependent and -independent mechanisms, thus adding another layer of complexity to sRNA-mediated riboregulation in Gram-positive species.
authors: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
authors: Jesper Sejrup
authors: JS
authors: Nielsen
authors: Lisbeth Kristensen
authors: LK
authors: Lei
authors: Tine
authors: T
authors: Ebersbach
authors: Anders Steno
authors: AS
authors: Olsen
authors: Janne Kudsk
authors: JK
authors: Klitgaard
authors: Poul
authors: P
authors: Valentin-Hansen
authors: Birgitte Haahr
authors: BH
authors: Kallipolitis
mesh_terms: D020029:Base Pairing; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D035001:Host Factor 1 Protein / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008089:Listeria monocytogenes / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010442:Peptide Chain Initiation, Translational; D014176:Protein Biosynthesis; D020871:RNA Stability; D016372:RNA, Antisense / Q000737:chemistry* / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D022661:RNA, Untranslated / Q000737:chemistry* / Q000235:genetics
chemical_list: D035001:Host Factor 1 Protein; D016372:RNA, Antisense; D012333:RNA, Messenger; D022661:RNA, Untranslated