title: Comparative study between transcriptionally- and translationally-acting adenine riboswitches reveals key differences in riboswitch regulatory mechanisms.
abstract: Many bacterial mRNAs are regulated at the transcriptional or translational level by ligand-binding elements called riboswitches. Although they both bind adenine, the adenine riboswitches of Bacillus subtilis and Vibrio vulnificus differ by controlling transcription and translation, respectively. Here, we demonstrate that, beyond the obvious difference in transcriptional and translational modulation, both adenine riboswitches exhibit different ligand binding properties and appear to operate under different regulation regimes (kinetic versus thermodynamic). While the B. subtilis pbuE riboswitch fully depends on co-transcriptional binding of adenine to function, the V. vulnificus add riboswitch can bind to adenine after transcription is completed and still perform translation regulation. Further investigation demonstrates that the rate of transcription is critical for the B. subtilis pbuE riboswitch to perform efficiently, which is in agreement with a co-transcriptional regulation. Our results suggest that the nature of gene regulation control, that is transcription or translation, may have a high importance in riboswitch regulatory mechanisms.
authors.affiliation: Groupe ARN/RNA Group, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lemay
authors.forename: Guillaume
authors.initials: G
authors.lastname: Desnoyers
authors.forename: Simon
authors.initials: S
authors.lastname: Blouin
authors.forename: Benoit
authors.initials: B
authors.lastname: Heppell
authors.forename: Laurène
authors.initials: L
authors.lastname: Bastet
authors.forename: Patrick
authors.initials: P
authors.lastname: St-Pierre
authors.forename: Eric
authors.initials: E
authors.lastname: Massé
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lafontaine
mesh_terms: D000225:Adenine / Q000737:chemistry; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D058928:Riboswitch / Q000235:genetics*; D014158:Transcription, Genetic; D020506:Untranslated Regions / Q000235:genetics; D041261:Vibrio vulnificus / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D058928:Riboswitch; D020506:Untranslated Regions; D000225:Adenine