Analyses of the regulatory mechanism and physiological roles of Pseudomonas aeruginosa OhrR, a transcription regulator and a sensor of organic hydroperoxides.
ohrR encodes an organic hydroperoxide sensor and a transcriptional repressor that regulates organic hydroperoxide-inducible expression of a thiol peroxidase gene, ohr, and itself. OhrR binds directly to the operators and represses transcription of these genes. Exposure to an organic hydroperoxide leads to oxidation of OhrR and to subsequent structural changes that result in the loss of the repressor's ability to bind to the operators that allow expression of the target genes. Differential induction of ohrR and ohr by tert-butyl hydroperoxide suggests that factors such as the repressor's dissociation constants for different operators and the chemical nature of the inducer contribute to OhrR-dependent organic hydroperoxide-inducible gene expression. ohrR and ohr mutants show increased and decreased resistance to organic hydroproxides, respectively, compared to a parental strain. Moreover, the ohrR mutant had a reduced-virulence phenotype in the Pseudomonas aeruginosa-Caenorhabditis elegans pathogenicity model.
Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand.
Sopapan
S
Atichartpongkul
Mayuree
M
Fuangthong
Paiboon
P
Vattanaviboon
Skorn
S
Mongkolsuk
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D017173:Caenorhabditis elegans / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D016297:Mutagenesis, Site-Directed; D009876:Operon / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014774:Virulence / Q000235:genetics / Q000502:physiology; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
D001426:Bacterial Proteins; D012097:Repressor Proteins; C112257:organic hydroperoxide resistance protein, Xanthomonas campestris; C122138:peroxide repressor proteins; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide