title: Riboswitches. A riboswitch-containing sRNA controls gene expression by sequestration of a response regulator.
abstract: The ethanolamine utilization (eut) locus of Enterococcus faecalis, containing at least 19 genes distributed over four polycistronic messenger RNAs, appears to be regulated by a single adenosyl cobalamine (AdoCbl)-responsive riboswitch. We report that the AdoCbl-binding riboswitch is part of a small, trans-acting RNA, EutX, which additionally contains a dual-hairpin substrate for the RNA binding-response regulator, EutV. In the absence of AdoCbl, EutX uses this structure to sequester EutV. EutV is known to regulate the eut messenger RNAs by binding dual-hairpin structures that overlap terminators and thus prevent transcription termination. In the presence of AdoCbl, EutV cannot bind to EutX and, instead, causes transcriptional read through of multiple eut genes. This work introduces riboswitch-mediated control of protein sequestration as a posttranscriptional mechanism to coordinately regulate gene expression.
authors.affiliation: Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, TX 77030, USA.
authors.forename: Sruti
authors.initials: S
authors.lastname: DebRoy
authors.affiliation: Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
authors.forename: Margo
authors.initials: M
authors.lastname: Gebbie
authors.affiliation: Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Arati
authors.initials: A
authors.lastname: Ramesh
authors.affiliation: Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Goodson
authors.affiliation: Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, TX 77030, USA.
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Cruz
authors.affiliation: Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, TX 77030, USA.
authors.forename: Ambro
authors.initials: A
authors.lastname: van Hoof
authors.affiliation: Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA. danielle.a.garsin@uth.tmc.edu wwinkler@umd.edu.
authors.forename: Wade C
authors.initials: WC
authors.lastname: Winkler
authors.affiliation: Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, TX 77030, USA. danielle.a.garsin@uth.tmc.edu wwinkler@umd.edu.
authors.forename: Danielle A
authors.initials: DA
authors.lastname: Garsin
mesh_terms: D001483:Base Sequence; D003038:Cobamides / Q000378:metabolism*; D013293:Enterococcus faecalis / Q000235:genetics* / Q000378:metabolism; D019856:Ethanolamine / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D058928:Riboswitch / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D003038:Cobamides; D012333:RNA, Messenger; D058928:Riboswitch; D019856:Ethanolamine; C000913:cobamamide