title: Promoter and riboswitch control of the Mg2+ transporter MgtA from Salmonella enterica.
abstract: The MgtA protein from Salmonella enterica serovar Typhimurium mediates Mg(2+) uptake from the periplasm into the cytoplasm. Here we report that the PhoP/PhoQ two-component regulatory system, which responds to periplasmic Mg(2+), governs mgtA transcription initiation at all investigated Mg(2+) concentrations and that the Mg(2+)-sensing 5' leader region of the mgtA gene controls transcription elongation into the mgtA coding region when Salmonella is grown in media with <50 muM Mg(2+). Overexpression of the Mg(2+) transporter CorA, which is believed to increase cytoplasmic Mg(2+) levels, decreased mgtA transcription in a manner dependent on a functional mgtA 5' leader.
authors.affiliation: Howard Hughes Medical Institute, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Cromie
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Groisman
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D015153:Blotting, Western; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics / Q000502:physiology; D008274:Magnesium / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; C079792:PhoQ protein, Bacteria; C061064:PhoP protein, Bacteria; D000251:Adenosine Triphosphatases; C093585:MgtA protein, bacteria; D008274:Magnesium