The Burkholderia pseudomallei oxyR gene: expression analysis and mutant characterization.
Burkholderia pseudomallei (Bp) is the causative agent of the life-threatening melioidosis in humans. The global transcription factor oxyR gene was isolated and characterized. It is located between recG, encoding a putative DNA helicase, and katG, encoding a putative catalase-peroxidase. oxyR is expressed as a monocistronic 1 kb mRNA and is induced by oxidative stress compounds. Northern, primer extension, and transcription reporter fusion analyses showed that oxyR mRNA is induced by 0.2 mM menadione, 2 mM paraquat, and 10 mM H(2)O(2). Two knockout mutants of oxyR were constructed, by single- and double-crossover recombination, and found to be hypersensitive to H(2)O(2) and paraquat. Bp lacking OxyR exhibited autoaggregation when cultured in liquid broth and an increased ability to form biofilms in minimal medium, but not in Luria-Bertani broth. The oxyR mutants also have a decreased level of extracellular protease activity. The altered phenotypes of oxyR deficient mutants were complemented when a copy of oxyR was transposed into the mutant chromosomes on the mini-Tn5 transposon.
Loprasert
Suvit
S
Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand. suvit@tubtim.cri.or.th
Sallabhan
Ratiboot
R
Whangsuk
Wirongrong
W
Mongkolsuk
Skorn
S
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D018441:Biofilms / Q000187:drug effects; D016957:Burkholderia pseudomallei / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D010450:Endopeptidases / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D023061:Gene Order; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; D006861:Hydrogen Peroxide; D010450:Endopeptidases