RcsB-BglJ activates the Escherichia coli leuO gene, encoding an H-NS antagonist and pleiotropic regulator of virulence determinants.

TitleRcsB-BglJ activates the Escherichia coli leuO gene, encoding an H-NS antagonist and pleiotropic regulator of virulence determinants.
Publication TypeJournal Article
Year of Publication2012
AuthorsStratmann, T, Pul, Ü, Wurm, R, Wagner, R, Schnetz, K
JournalMol Microbiol
Volume83
Issue6
Pagination1109-23
Date Published2012 Mar
ISSN1365-2958
KeywordsBase Sequence, DNA-Binding Proteins, Escherichia coli, Escherichia coli Proteins, Fimbriae Proteins, Gene Expression Regulation, Bacterial, Molecular Chaperones, Molecular Sequence Data, Operon, Promoter Regions, Genetic, Protein Binding, Trans-Activators, Transcriptional Activation, Transcription Factors, Virulence Factors
Abstract

The LysR-type transcription factor LeuO is involved in regulation of pathogenicity determinants and stress responses in Enterobacteriaceae, and acts as antagonist of the global repressor H-NS. Expression of the leuO gene is repressed by H-NS, and it is upregulated in stationary phase and under amino acid starvation conditions. Here, we show that the heterodimer of the FixJ/NarL-type transcription regulators RcsB and BglJ strongly activates expression of leuO and that RcsB-BglJ regulates additional loci. Activation of leuO by RcsB-BglJ is independent of the Rcs phosphorelay system. RcsB-BglJ binds to the leuO promoter region and activates one of two leuO promoters mapped in vivo. Moreover, LeuO antagonizes activation of leuO by RcsB-BglJ and acts as negative autoregulator in vivo and in vitro. Further, the H-NS paralogue StpA causes repression of leuO in addition to H-NS. Together, our data suggest a complex arrangement of regulatory elements and they indicate a feedback control mechanism of leuO expression.

DOI10.1111/j.1365-2958.2012.07993.x
Alternate JournalMol. Microbiol.