The Burkholderia pseudomallei oxyR gene: expression analysis and mutant characterization

• Published in: Gene 2002-08, Vol.296 (1-2), p.161-169
• Main Authors: Loprasert, Suvit, Sallabhan, Ratiboot, Whangsuk, Wirongrong, Mongkolsuk, Skorn
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - genetics; Base Sequence; Biofilms - drug effects; Burkholderia pseudomallei - drug effects; Burkholderia pseudomallei - genetics; Burkholderia pseudomallei - metabolism; Cell Division - drug effects; Cell Division - genetics; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; DNA-Binding Proteins; Dose-Response Relationship, Drug; Endopeptidases - metabolism; Gene Expression Regulation, Bacterial - drug effects; Gene Order; Genetic Complementation Test; Hydrogen Peroxide - pharmacology; Molecular Sequence Data; Mutation; Repressor Proteins - genetics; RNA, Messenger - drug effects; RNA, Messenger - genetics; RNA, Messenger - metabolism; Sequence Analysis, DNA; Transcription Factors - genetics
• ISSN: 0378-1119
• DOI: 10.1016/S0378-1119(02)00854-5

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.