title: Repression of flagellar genes in exponential phase by CsgD and CpxR, two crucial modulators of Escherichia coli biofilm formation.
abstract: Escherichia coli adapts its lifestyle to the variations of environmental growth conditions, swapping between swimming motility or biofilm formation. The stationary-phase sigma factor RpoS is an important regulator of this switch, since it stimulates adhesion and represses flagellar biosynthesis. By measuring the dynamics of gene expression, we show that RpoS inhibits the transcription of the flagellar sigma factor, FliA, in exponential growth phase. RpoS also partially controls the expression of CsgD and CpxR, two transcription factors important for bacterial adhesion. We demonstrate that these two regulators repress the transcription of fliA, flgM, and tar and that this regulation is dependent on the growth medium. CsgD binds to the flgM and fliA promoters around their -10 promoter element, strongly suggesting direct repression. We show that CsgD and CpxR also affect the expression of other known modulators of cell motility. We propose an updated structure of the regulatory network controlling the choice between adhesion and motility.
authors.affiliation: Laboratoire Adaptation et Pathogénie des Micro-organismes, UMR5163, Institut Jean Roget, Domaine de la Merci, Université Joseph Fourier, Grenoble, France.
authors.forename: Omaya
authors.initials: O
authors.lastname: Dudin
authors.forename: Johannes
authors.initials: J
authors.lastname: Geiselmann
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ogasawara
authors.forename: Akira
authors.initials: A
authors.lastname: Ishihama
authors.forename: Stéphan
authors.initials: S
authors.lastname: Lacour
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C499694:CsgD protein, E coli; D029968:Escherichia coli Proteins; D012808:Sigma Factor; D015534:Trans-Activators; C069567:sigma factor KatF protein, Bacteria; C085504:CpxR protein, Bacteria; D000242:Cyclic AMP