title: A role for the PhoBR regulatory system homologue in the Vibrio cholerae phosphate-limitation response and intestinal colonization.
abstract: To survive and multiply in different environments, Vibrio cholerae has to coordinately regulate the expression of genes involved in adaptive responses. In many pathogens, adaptive responses, including pathogenic responses, are regulated by two-component regulator (TCR) systems. It is likely that members of a TCR family play a role in the regulation of processes involved in intestinal colonization, and therefore pathogenesis, in V. cholerae. We have identified and characterized a TCR system of V. cholerae: this system is a homologue of Escherichia coli PhoBR. The presence of a putative Pho box suggests that the V. cholerae phoBR operon is regulated by inorganic phosphate levels. The phoR and phoB genes are organized the same way as in E. coli. Mutation of the V. cholerae phoB gene affected the expression of the putative Pho regulon, including PhoA, but did not affect the production of cholera toxin. V. cholerae phoB mutants are less able to colonize rabbit intestine than wild-type V. cholerae. The addition of inorganic phosphate at a high concentration to the inoculum only partially restored the ability of the mutants to colonize the intestine, suggesting that the V. cholerae Pho regulon in vivo may not be regulated by inorganic phosphate levels alone.
authors.affiliation: Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK1.
authors.forename: W M A
authors.initials: WMA
authors.lastname: von Krüger
authors.affiliation: Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK1.
authors.forename: S
authors.initials: S
authors.lastname: Humphreys
authors.affiliation: Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK1.
authors.forename: J M
authors.initials: JM
authors.lastname: Ketley
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000714:Anastomosis, Surgical; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002772:Cholera Toxin / Q000378:metabolism; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007082:Ileum / Q000382:microbiology / Q000601:surgery; D007413:Intestinal Mucosa / Q000382:microbiology*; D008969:Molecular Sequence Data; D010710:Phosphates / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D017422:Sequence Analysis, DNA; D014734:Vibrio cholerae / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D010710:Phosphates; C061278:PhoB protein, Bacteria; C061279:PhoR protein, Bacteria; D002772:Cholera Toxin; D011494:Protein Kinases; D000469:Alkaline Phosphatase