title: Global gene expression and phenotypic analysis of a Vibrio cholerae rpoH deletion mutant.
abstract: Vibrio cholerae, the cause of cholera, can grow in a variety of environments outside of human hosts. During infection, this pathogen must adapt to significant environmental alterations, including the elevated temperature of the human gastrointestinal tract. Sigma(32), an alternative sigma factor encoded by rpoH, activates transcription of genes involved in the heat shock response in several bacterial species. Here, we assessed the role of sigma(32) in V. cholerae physiology. In aggregate, our findings suggest that sigma(32) promotes V. cholerae growth at temperatures ranging at least from 15 degrees C to 42 degrees C. Growth of the rpoH mutant was severely attenuated within the suckling mouse intestine, suggesting that sigma(32)-regulated genes are critical for V. cholerae adaptation to conditions within the gastrointestinal tract. We defined the V. cholerae RpoH regulon by comparing the whole-genome transcription profiles of the wild-type and rpoH mutant strains after a temperature up-shift. Most of the V. cholerae genes expressed in an RpoH-dependent manner after heat shock encode proteins that influence protein fate, such as proteases and chaperones, or are of unknown function. Bioinformatic analyses of the microarray data were used to define a putative sigma(32) consensus binding sequence and subsequently to identify genes that are likely to be directly regulated by RpoH in the whole V. cholerae genome.
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA.
authors.forename: Leyla
authors.initials: L
authors.lastname: Slamti
authors.forename: Jonathan
authors.initials: J
authors.lastname: Livny
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Waldor
mesh_terms: D000818:Animals; D000833:Animals, Suckling; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002771:Cholera / Q000382:microbiology; D019295:Computational Biology; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics*; D018869:Heat-Shock Response / Q000235:genetics; D007422:Intestines / Q000382:microbiology; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D018085:Regulon / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012808:Sigma Factor / Q000235:genetics*; D013696:Temperature; D013997:Time Factors; D014158:Transcription, Genetic; D014734:Vibrio cholerae / Q000235:genetics* / Q000254:growth & development
chemical_list: D006360:Heat-Shock Proteins; D012808:Sigma Factor; C069774:heat-shock sigma factor 32