title: Characterization of the OxyR regulon of Neisseria gonorrhoeae.
abstract: OxyR regulates the expression of the majority of H(2)O(2) responses in Gram-negative organisms. In a previous study we reported the OxyR-dependent derepression of catalase expression in the human pathogen Neisseria gonorrhoeae. In the present study we used microarray expression profiling of N. gonorrhoeae wild-type strain 1291 and an oxyR mutant strain to define the OxyR regulon. In addition to katA (encoding catalase), only one other locus displayed a greater than two-fold difference in expression in the wild type : oxyR comparison. This locus encodes an operon of two genes, a putative peroxiredoxin/glutaredoxin (Prx) and a putative glutathione oxidoreductase (Gor). Mutant strains were constructed in which each of these genes was inactivated. A previous biochemical study in Neisseria meningitidis had confirmed function of the glutaredoxin/peroxiredoxin. Assay of the wild-type 1291 cell free extract confirmed Gor activity, which was lost in the gor mutant strain. Phenotypic analysis of the prx mutant strain in H(2)O(2) killing assays revealed increased resistance, presumably due to upregulation of alternative defence mechanisms. The oxyR, prx and gor mutant strains were deficient in biofilm formation, and the oxyR and prx strains had decreased survival in cervical epithelial cells, indicating a key role for the OxyR regulon in these processes.
authors.affiliation: School of Molecular and Microbial Sciences and Centre for Metals in Biology, The University of Queensland, Brisbane 4072, Qld, Australia.
authors.forename: Kate L
authors.initials: KL
authors.lastname: Seib
authors.forename: Hsing-Ju
authors.initials: HJ
authors.lastname: Wu
authors.forename: Yogitha N
authors.initials: YN
authors.lastname: Srikhanta
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Edwards
authors.forename: Megan L
authors.initials: ML
authors.lastname: Falsetta
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Hamilton
authors.forename: Tina L
authors.initials: TL
authors.lastname: Maguire
authors.forename: Sean M
authors.initials: SM
authors.lastname: Grimmond
authors.forename: Michael A
authors.initials: MA
authors.lastname: Apicella
authors.forename: Alastair G
authors.initials: AG
authors.lastname: McEwan
authors.forename: Michael P
authors.initials: MP
authors.lastname: Jennings
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D008969:Molecular Sequence Data; D009344:Neisseria gonorrhoeae / Q000201:enzymology / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D018085:Regulon / Q000235:genetics* / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C499299:oxyR protein, E coli