title: Identification of multiple sigma54-dependent transcriptional activators in Vibrio cholerae.
abstract: In the pathogenic bacterium Vibrio cholerae, the alternate sigma factor sigma54 is required for expression of multiple sets of genes, including an unidentified gene(s) necessary for enhanced colonization within the host. To identify sigma54-dependent transcriptional activators involved in colonization, PCR was performed with V. cholerae chromosomal DNA and degenerate primers, revealing six novel and distinct coding sequences with homology to sigma54-dependent activators. One sequence had high homology to the luxO gene of V. harveyi, which in that organism is involved in quorum sensing. Phenotypes of V. cholerae strains containing mutations in each of the six putative sigma54-dependent activator genes identified one as a probable ntrC homologue. None of the mutant strains exhibited a defect in the ability to colonize infant mice, suggesting the presence of additional sigma54-dependent activators not identified by this technique.
authors.affiliation: Department of Microbiology, University of Texas Health Science Center, San Antonio, Texas 78284-7758, USA klose@uthscsa.edu
authors.forename: K E
authors.initials: KE
authors.lastname: Klose
authors.forename: V
authors.initials: V
authors.lastname: Novik
authors.forename: J J
authors.initials: JJ
authors.lastname: Mekalanos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000502:physiology*; D005974:Glutamate-Ammonia Ligase / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D051877:RNA Polymerase Sigma 54; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000502:physiology*; D015534:Trans-Activators / Q000502:physiology*; D014734:Vibrio cholerae / Q000235:genetics* / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012808:Sigma Factor; D015534:Trans-Activators; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54; C081173:glutamine synthetase I; D005974:Glutamate-Ammonia Ligase