| The effects of amino acid supplementation on porin expression and ToxR levels in Vibrio cholerae. | |
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MedLine Citation:
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PMID: 22144480 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Vibrio cholerae responds to environmental changes by altering the protein composition of its outer membrane. In rich medium, V. cholerae expresses almost exclusively the outer membrane porin OmpU, whereas in minimal medium, OmpT is the dominant porin. Supplementing a minimal medium with a mixture of asparagine, arginine, glutamic acid and serine (NRES) promotes OmpU production and OmpT repression similar to levels seen in rich media. Here we show that the altered Omp profile is not due to a growth rate increase in the presence of supplemental amino acids, but requires the addition of specific amino acids. The effects of the NRES mix on Omp production were mediated by ToxR, a known regulator of omp gene expression. No changes in the Omp profile were detected in a toxR mutant. Supplementing with the NRES mix resulted in significantly higher levels of ToxR, and elevated ToxR was sufficient to cause a switch in Omp synthesis. The increase in ToxR protein correlated with an increase in toxR mRNA, and was observed only when toxR was expressed from its native promoter. ToxS, which is required for ToxR activity, was necessary for the NRES-mediated omp gene regulation, but not for the increase in ToxR levels. Growth of V. cholerae in the presence of bile acids also resulted in Omp switching, and this required ToxR. However, unlike the NRES mix, bile acids did not increase either ToxR protein or toxR mRNA, suggesting a different mechanism of omp gene regulation by bile than by amino acids. |
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Authors:
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Alexandra R Mey; Stephanie A Craig; Shelley M Payne |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-12-5 |
Journal Detail:
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Title: Infection and immunity Volume: - ISSN: 1098-5522 ISO Abbreviation: - Publication Date: 2011 Dec |
Date Detail:
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Created Date: 2011-12-6 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0246127 Medline TA: Infect Immun Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Section of Molecular Genetics and Microbiology and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, 78712-1095. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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