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PubMed · 8955299

Two-component regulatory systems can interact to process multiple environmental signals.

F C Soncini·E A Groisman
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Abstract

The PhoP/PhoQ two-component system of Salmonella typhimurium governs transcription of some 25 loci in response to the extracellular concentration of Mg2+. We have now identified one of these loci as pmrCAB, which codes for a two-component system that mediates resistance to the antibiotic polymyxin B. Transcription of seven of 25 PhoP-activated loci was dependent on a functional PmrA protein, the response regulator of the PmrA/PmrB system. Expression of the PmrA-dependent loci was induced by either Mg2+ limitation or mild acidification, whereas transcription of a PmrA-independent gene was activated by Mg2+ limitation but not acid pH. Induction of PmrA-activated genes by Mg2 limitation required the PhoP and PhoQ proteins. In contrast, the acid-mediated activation of PmrA-regulated genes occurred in strains that were missing either one of these proteins. Transcriptional regulation by a cascade of two-component systems allows pathogenic bacteria to express their virulence determinants in response to a broader spectrum of environmental cues.

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Bacterial ProteinsCulture MediaGene Expression Regulation, BacterialHydrogen-Ion ConcentrationMagnesiumMutagenesis, InsertionalOperonSalmonella typhimuriumTranscription FactorsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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BibTeXRIS

F C Soncini, E A Groisman. 1996. Two-component regulatory systems can interact to process multiple environmental signals.. https://doi.org/10.1128/jb.178.23.6796-6801.1996

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