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.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / genetics*
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Adenosine Triphosphatases / metabolism*
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Bacterial Proteins / genetics*
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Bacterial Proteins / metabolism*
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Blotting, Western
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Gene Expression Regulation, Bacterial / genetics
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Gene Expression Regulation, Bacterial / physiology
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Magnesium / metabolism
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Membrane Transport Proteins / genetics*
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Membrane Transport Proteins / metabolism*
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Promoter Regions, Genetic / genetics*
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Salmonella typhimurium / genetics*
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Salmonella typhimurium / metabolism*
Substances
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Bacterial Proteins
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Membrane Transport Proteins
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PhoQ protein, Bacteria
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PhoP protein, Bacteria
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Adenosine Triphosphatases
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MgtA protein, bacteria
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Magnesium