title: An RNA sensor for intracellular Mg(2+).
abstract: Most RNA molecules require Mg(2+) for their structure and enzymatic properties. Here we report the first example of an RNA serving as sensor for cytoplasmic Mg(2+). We establish that expression of the Mg(2+) transporter MgtA of Salmonella enterica serovar Typhimurium is controlled by its 5' untranslated region (5'UTR). We show that the 5'UTR of the mgtA gene can adopt different stem-loop structures depending on the Mg(2+) levels, which determine whether transcription reads through into the mgtA coding region or stops within the 5'UTR. We could recapitulate the Mg(2+)-regulated transcription using a defined in vitro transcription system with RNA polymerase as the only protein component. The initiation of mgtA transcription responds to extracytoplasmic Mg(2+) and its elongation into the coding region to cytoplasmic Mg(2+), providing a singular example in which the same ligand is sensed in different cellular compartments to regulate disparate steps in gene transcription.
authors.affiliation: Howard Hughes Medical Institute, Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8230, St. Louis, MO 63110, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Cromie
authors.forename: Yixin
authors.initials: Y
authors.lastname: Shi
authors.forename: Tammy
authors.initials: T
authors.lastname: Latifi
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Groisman
mesh_terms: D020121:5' Untranslated Regions / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D015374:Biosensing Techniques / Q000379:methods*; D017124:Conserved Sequence / Q000235:genetics; D003593:Cytoplasm / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial; D008274:Magnesium / Q000032:analysis* / Q000378:metabolism* / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000235:genetics; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation / Q000187:drug effects; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics; D012329:RNA, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012260:Ribonucleases / Q000378:metabolism; D013728:Terminator Regions, Genetic / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012260:Ribonucleases; D000251:Adenosine Triphosphatases; C093585:MgtA protein, bacteria; D008274:Magnesium