Mutation analysis of the Pseudomonas aeruginosa mvfR and pqsABCDE gene promoters demonstrates complex quorum-sensing circuitry.
The LysR-type transcriptional regulator MvfR (PqsR) (multiple virulence factor regulator) plays a critical role in Pseudomonas aeruginosa pathogenicity via the transcriptional regulation of multiple quorum-sensing (QS)-regulated virulence factors. LasR activates full mvfR transcription, and MvfR subsequently activates pqsA-E expression. This study identifies and characterizes the key cis-regulatory elements through which mvfR and pqsA-E transcription is regulated in the highly virulent P. aeruginosa strain PA14. Deletion and site-directed mutagenesis indicate that: (1) LasR activates mvfR transcription by binding to a las/rhl box, CTAACAAAAGACATAG, centred at -513 bp upstream of the MvfR translational start site; and (2) RhlR represses pqsA transcription by binding to a las/rhl box, CTGTGAGATTTGGGAG, centred at -311 bp upstream of the pqsA transcriptional initiation site. Furthermore, it is shown that MvfR activates pqsA-E transcription by binding to a LysR box, TTCGGACTCCGAA, centred at -45 bp relative to the pqsA transcriptional initiation site, demonstrating that this LysR box has a critical role in the physical interaction between the MvfR protein and the pqsA promoter. These results provide new insights into the regulatory relationships between LasR and mvfR, and between MvfR/RhlR and the pqs operon, and elucidate further the complex regulation of the P. aeruginosa QS circuitry.
Xiao
Gaoping
G
Department of Surgery, Microbiology and Molecular Genetics, Harvard Medical School, Department of Surgery, Massachusetts General Hospital, and Shriners Burns Institute, Boston, MA 02114, USA.
He
Jianxin
J
Department of Surgery, Microbiology and Molecular Genetics, Harvard Medical School, Department of Surgery, Massachusetts General Hospital, and Shriners Burns Institute, Boston, MA 02114, USA.
Rahme
Laurence G
LG
Department of Surgery, Microbiology and Molecular Genetics, Harvard Medical School, Department of Surgery, Massachusetts General Hospital, and Shriners Burns Institute, Boston, MA 02114, USA.
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C080365:LasR protein, Pseudomonas aeruginosa; D015534:Trans-Activators; D014157:Transcription Factors; D037521:Virulence Factors