Quorum-sensing regulation of a copper toxicity system in Pseudomonas aeruginosa.
The LasR/LasI quorum-sensing system in Pseudomonas aeruginosa influences global gene expression and mediates pathogenesis. In this study, we show that the quorum-sensing system activates, via the transcriptional regulator PA4778, a copper resistance system composed of 11 genes. The quorum-sensing global regulator LasR was recently shown to directly activate transcription of PA4778, a cueR homolog and a MerR-type transcriptional regulator. Using molecular genetic methods and bioinformatics, we verify the interaction of LasR with the PA4778 promoter and further demonstrate the LasR binding site. We also identify a putative PA4778 binding motif and show that the protein directly binds to and activates five promoters controlling the expression of 11 genes--PA3519 to -15, PA3520, mexPQ-opmE, PA3574.1, and cueA, a virulence factor in a murine model. Using gene disruptions, we show that PA4778, along with 7 of 11 gene targets of PA4778, increases the sensitivity of P. aeruginosa to elevated copper concentrations. This work identifies a cellular function for PA4778 and four other previously unannotated genes (PA3515, PA3516, PA3517, and PA3518) and suggests a potential role for copper in the quorum response. We propose to name PA4778 cueR.
Department of Biomedical Engineering, Boston University College of Engineering, Boston, Massachusetts 02215, USA.
Joshua T
JT
Thaden
Stephen
S
Lory
Timothy S
TS
Gardner
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D019295:Computational Biology; D003300:Copper / Q000633:toxicity*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D053038:Quorum Sensing / Q000187:drug effects* / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C080365:LasR protein, Pseudomonas aeruginosa; C051124:MerR protein, Bacteria; D015534:Trans-Activators; D003300:Copper