title: Riboswitches. Sequestration of a two-component response regulator by a riboswitch-regulated noncoding RNA.
abstract: Riboswitches are ligand-binding elements contained within the 5' untranslated regions of bacterial transcripts, which generally regulate expression of downstream open reading frames. Here, we show that in Listeria monocytogenes, a riboswitch that binds vitamin B12 controls expression of a noncoding regulatory RNA, Rli55. Rli55, in turn, controls expression of the eut genes, whose products enable ethanolamine utilization and require B12 as a cofactor. Defects in ethanolamine utilization, or in its regulation by Rli55, significantly attenuate Listeria virulence in mice. Rli55 functions by sequestering the two-component response regulator EutV by means of a EutV-binding site contained within the RNA. Thus, Rli55 is a riboswitch-regulated member of the small group of regulatory RNAs that function by sequestering a protein and reveals a distinctive mechanism of signal integration in bacterial gene regulation.
authors.affiliation: Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015 Paris, France. INSERM, U604, Paris, F-75015 France. INRA, USC2020, F-75015 Paris, France.
authors.forename: J R
authors.initials: JR
authors.lastname: Mellin
authors.affiliation: Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015 Paris, France. INSERM, U604, Paris, F-75015 France. INRA, USC2020, F-75015 Paris, France.
authors.forename: Mikael
authors.initials: M
authors.lastname: Koutero
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Dar
authors.affiliation: Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015 Paris, France. INSERM, U604, Paris, F-75015 France. INRA, USC2020, F-75015 Paris, France.
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Nahori
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Rotem
authors.initials: R
authors.lastname: Sorek
authors.affiliation: Unité des Interactions Bactéries-Cellules, Institut Pasteur, F-75015 Paris, France. INSERM, U604, Paris, F-75015 France. INRA, USC2020, F-75015 Paris, France. pcossart@pasteur.fr.
authors.forename: Pascale
authors.initials: P
authors.lastname: Cossart
mesh_terms: D020121:5' Untranslated Regions; D000818:Animals; D019856:Ethanolamine / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008089:Listeria monocytogenes / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D009876:Operon; D022661:RNA, Untranslated / Q000378:metabolism*; D020218:Response Elements; D058928:Riboswitch; D014805:Vitamin B 12 / Q000378:metabolism*
chemical_list: D020121:5' Untranslated Regions; D022661:RNA, Untranslated; D058928:Riboswitch; D019856:Ethanolamine; D014805:Vitamin B 12