title: The expression of Longus type 4 pilus of enterotoxigenic Escherichia coli is regulated by LngR and LngS and by H-NS, CpxR and CRP global regulators.
abstract: Enterotoxigenic Escherichia coli produces a long type 4 pilus called Longus. The regulatory elements and the environmental signals controlling the expression of Longus-encoding genes are unknown. We identified two genes lngR and lngS in the Longus operon, whose predicted products share homology with transcriptional regulators. Isogenic lngR and lngS mutants were considerably affected in transcription of lngA pilin gene. The expression of lngA, lngR and lngS genes was optimally expressed at 37°C at pH 7.5. The presence of glucose and sodium chloride had a positive effect on Longus expression. The presence of divalent ions, particularly calcium, appears to be an important stimulus for Longus production. In addition, we studied H-NS, CpxR and CRP global regulators, on Longus expression. The response regulator CpxR appears to function as a positive regulator of lng genes as the cpxR mutant showed reduced levels of lngRSA expression. In contrast, H-NS and CRP function as negative regulators since expression of lngA was up-regulated in isogenic hns and crp mutants. H-NS and CRP were required for salt- and glucose-mediated regulation of Longus. Our data suggest the existence of a complex regulatory network controlling Longus expression, involving both local and global regulators in response to different environmental signals.
authors.affiliation: Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI IMSS, Mexico City, Mexico.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: De la Cruz
authors.affiliation: Facultad de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ruiz-Tagle
authors.affiliation: Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI IMSS, Mexico City, Mexico.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Ares
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología UNAM, Cuernavaca, Mexico.
authors.forename: Sabino
authors.initials: S
authors.lastname: Pacheco
authors.affiliation: Facultad de Estomatología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Yáñez
authors.affiliation: Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.
authors.forename: Lilia
authors.initials: L
authors.lastname: Cedillo
authors.affiliation: Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI IMSS, Mexico City, Mexico.
authors.forename: Javier
authors.initials: J
authors.lastname: Torres
authors.affiliation: Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.|Department of Pediatrics, University of Virginia, Charlottesville, VA, 22908, USA.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Girón
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D053263:Gene Regulatory Networks / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D002373:Cyclic AMP Receptor Protein; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C121921:LngA protein, E coli; C000622751:LngR protein, E coli; C000622752:LngS protein, E coli; D015534:Trans-Activators; D037521:Virulence Factors; C481662:crp protein, E coli; D036781:Fimbriae Proteins; C085504:CpxR protein, Bacteria