1887

Abstract

The LysR-type transcriptional regulator MvfR (PqsR) (ultiple irulence actor egulator) plays a critical role in pathogenicity via the transcriptional regulation of multiple quorum-sensing (QS)-regulated virulence factors. LasR activates full transcription, and MvfR subsequently activates expression. This study identifies and characterizes the key -regulatory elements through which and transcription is regulated in the highly virulent strain PA14. Deletion and site-directed mutagenesis indicate that: (1) LasR activates transcription by binding to a / box, CTAACAAAAGACATAG, centred at −513 bp upstream of the MvfR translational start site; and (2) RhlR represses transcription by binding to a / box, CTGTGAGATTTGGGAG, centred at −311 bp upstream of the transcriptional initiation site. Furthermore, it is shown that MvfR activates transcription by binding to a box, TTCGGACTCCGAA, centred at −45 bp relative to the transcriptional initiation site, demonstrating that this box has a critical role in the physical interaction between the MvfR protein and the promoter. These results provide new insights into the regulatory relationships between LasR and , and between MvfR/RhlR and the operon, and elucidate further the complex regulation of the QS circuitry.

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2006-06-01
2019-12-14
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