title: The two-component response regulator PprB modulates quorum-sensing signal production and global gene expression in Pseudomonas aeruginosa.
abstract: The response regulator PprB and its cognate sensor PprA were recently reported as a two-component regulatory system that controls membrane permeability and antibiotic sensitivity of Pseudomonas aeruginosa. We found that a Tn5 insertion mutation in pprB caused a drastic reduction in virulence factor production and cell motility. A transcriptome analysis revealed that 175 genes were regulated by PprB. Among the 113 PprB-activated genes, 85.5% are known to be activated by N-3-oxo-dodecanoyl-homoserine lactone (OdDHL) and N-butanoyl-homoserine lactone (BHL). In particular, the expression of lasI, rhlI and rhlR, which encode key components of the las and rhl quorum-sensing (QS) systems, were significantly decreased in the pprB mutant. These data suggest that PprB might regulate QS signal production. Measurement of OdDHL and BHL in cultures of the mutant sustained this hypothesis. By using various OdDHL- or BHL-responsive QS reporter systems, including lasB-lacZ, lasI-lacZ and rsaL-lacZ, we found that the mutation in pprB resulted in a large decrease in the sensitivity of P. aeruginosa to exogenous OdDHL. However, there was no difference in sensitivity to BHL. Further analysis showed that the OdDHL influx was significantly reduced in the pprB mutant. We conclude that PprB is a novel QS modulator that positively regulates N-acylhomoserine lactone production probably by affecting the OdDHL signal influx and thereby influences global expression of the QS-dependent genes.
authors.affiliation: Institute of Molecular and Cell Biology, 61 Biopolis Drive, 138673, Singapore.
authors.forename: Yi-Hu
authors.initials: YH
authors.lastname: Dong
authors.forename: Xi-Fen
authors.initials: XF
authors.lastname: Zhang
authors.forename: Hui-Meng Linda
authors.initials: HM
authors.lastname: Soo
authors.forename: Everett P
authors.initials: EP
authors.lastname: Greenberg
authors.forename: Lian-Hui
authors.initials: LH
authors.lastname: Zhang
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000032:analysis; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D004251:DNA Transposable Elements; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter / Q000502:physiology; D006714:Homoserine / Q000031:analogs & derivatives / Q000032:analysis; D008025:Ligases / Q000096:biosynthesis; D008969:Molecular Sequence Data; D009068:Movement; D016254:Mutagenesis, Insertional; D020411:Oligonucleotide Array Sequence Analysis; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000096:biosynthesis; D037521:Virulence Factors / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C081237:LasI protein, Pseudomonas aeruginosa; C109860:N-(3-oxododecanoyl)homoserine lactone; C092312:N-butyrylhomoserine lactone; C086515:RhlR protein, Pseudomonas aeruginosa; D015534:Trans-Activators; D014157:Transcription Factors; D037521:Virulence Factors; C112177:osmolarity response regulator proteins; D006714:Homoserine; D008025:Ligases; C096955:RHLI protein, Pseudomonas aeruginosa; D015107:4-Butyrolactone