title: YjjQ Represses Transcription of flhDC and Additional Loci in Escherichia coli.
abstract: The presumptive transcriptional regulator YjjQ has been identified as being virulence associated in avian pathogenic Escherichia coli (APEC). In this work, we characterize YjjQ as transcriptional repressor of the flhDC operon, encoding the master regulator of flagellar synthesis, and of additional loci. The latter include gfc (capsule 4 synthesis), ompC (outer membrane porin C), yfiRNB (regulated c-di-GMP synthesis), and loci of poorly defined function (ybhL and ymiA-yciX). We identify the YjjQ DNA-binding sites at the flhDC and gfc promoters and characterize a DNA-binding sequence motif present at all promoters found to be repressed by YjjQ. At the flhDC promoter, the YjjQ DNA-binding site overlaps the RcsA-RcsB DNA-binding site. RcsA-RcsB likewise represses the flhDC promoter, but the repression by YjjQ and that by RcsA-RcsB are independent of each other. These data suggest that YjjQ is an additional regulator involved in the complex control of flhDC at the level of transcription initiation. Furthermore, we show that YjjQ represses motility of the E. coli K-12 laboratory strain and of uropathogenic E. coli (UPEC) strains CFT073 and 536. Regulation of flhDC, yfiRNB, and additional loci by YjjQ may be features relevant for pathogenicity.
  
  
  OBJECTIVE
  Escherichia coli is a commensal and pathogenic bacterium causing intra- and extraintestinal infections in humans and farm animals. The pathogenicity of E. coli strains is determined by their particular genome content, which includes essential and associated virulence factors that control the cellular physiology in the host environment. However, the gene pools of commensal and pathogenic E. coli are not clearly differentiated, and the function of virulence-associated loci needs to be characterized. In this study, we characterize the function of yjjQ, encoding a transcription regulator that was identified as being virulence associated in avian pathogenic E. coli (APEC). We characterize YjjQ as transcriptional repressor of flagellar motility and of additional loci related to pathogenicity.
authors.affiliation: Institute for Genetics, University of Cologne, Cologne, Germany.
authors.forename: Helene
authors.initials: H
authors.lastname: Wiebe
authors.affiliation: Center for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany.
authors.forename: Doreen
authors.initials: D
authors.lastname: Gürlebeck
authors.affiliation: Institute for Genetics, University of Cologne, Cologne, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Groß
authors.affiliation: Institute for Genetics, University of Cologne, Cologne, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Dreck
authors.affiliation: Institute for Genetics, University of Cologne, Cologne, Germany.
authors.forename: Derk
authors.initials: D
authors.lastname: Pannen
authors.affiliation: Institute for Hygiene and Infectious Diseases of Animals, Justus-Liebig-Universität Giessen, Giessen, Germany.
authors.forename: Christa
authors.initials: C
authors.lastname: Ewers
authors.affiliation: Center for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany Robert Koch Institute, Berlin, Germany.
authors.forename: Lothar H
authors.initials: LH
authors.lastname: Wieler
authors.affiliation: Institute for Genetics, University of Cologne, Cologne, Germany schnetz@uni-koeln.de.
authors.forename: Karin
authors.initials: K
authors.lastname: Schnetz
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D063185:Epigenetic Repression; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D056426:Genetic Loci; D009876:Operon / Q000235:genetics; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D037521:Virulence Factors / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D014157:Transcription Factors; D037521:Virulence Factors; C529263:YjjQ protein, E coli