Expression of the mexA gene requires the DNA helicase RecG in Pseudomonas aeruginosa PAO1

This study provides evidence that RecG regulates the expression of the OxyR-independent gene mexA in Pseudomonas aeruginosa PAO1. A reduction in mexA expression was observed in the absence of RecG, but not OxyR, by northern blot and quantitative real-time PCR analyses. The canonical palindromic RecG binding sequence was present upstream of the mexA promoter, and bound purified RecG and single strand-binding protein. These data reveal a novel mechanism of OxyR-independent gene transcription by RecG.