title: RcsB-BglJ activates the Escherichia coli leuO gene, encoding an H-NS antagonist and pleiotropic regulator of virulence determinants.
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.
authors.affiliation: Institut für Genetik, Universität zu Köln, Zülpicher Str. 47a, 50674 Köln, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Stratmann
authors.forename: Ümit
authors.initials: Ü
authors.lastname: Pul
authors.forename: Reinhild
authors.initials: R
authors.lastname: Wurm
authors.forename: Rolf
authors.initials: R
authors.lastname: Wagner
authors.forename: Karin
authors.initials: K
authors.lastname: Schnetz
mesh_terms: D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C103411:BglJ protein, E coli; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C529458:FimG protein, E coli; C430340:LeuO protein, E coli; D018832:Molecular Chaperones; C489568:RcsB protein, E coli; C090104:StpA protein, E coli; D015534:Trans-Activators; D014157:Transcription Factors; D037521:Virulence Factors; D036781:Fimbriae Proteins