title: Transcriptional regulation of opaR, qrr2-4 and aphA by the master quorum-sensing regulator OpaR in Vibrio parahaemolyticus.
abstract: BACKGROUND
  Vibrio parahaemolyticus is a leading cause of infectious diarrhea and enterogastritis via the fecal-oral route. V. harveyi is a pathogen of fishes and invertebrates, and has been used as a model for quorum sensing (QS) studies. LuxR is the master QS regulator (MQSR) of V. harveyi, and LuxR-dependent expression of its own gene, qrr2-4 and aphA have been established in V. harveyi. Molecular regulation of target genes by the V. parahaemolyticus MQSR OpaR is still poorly understood.
  
  
  RESULTS
  The bioinformatics analysis indicated that V. parahaemolyticus OpaR, V. harveyi LuxR, V. vulnificu SmcR, and V. alginolyticus ValR were extremely conserved, and that these four MQSRs appeared to recognize the same conserved cis-acting signals, which was represented by the consensus constructs manifesting as a position frequency matrix and as a 20 bp box, within their target promoters. The MQSR box-like sequences were found within the upstream DNA regions of opaR, qrr2-4 and aphA in V. parahaemolyticus, and the direct transcriptional regulation of these target genes by OpaR were further confirmed by multiple biochemical experiments including primer extension assay, gel mobility shift assay, and DNase I footprinting analysis. Translation and transcription starts, core promoter elements for sigma factor recognition, Shine-Dalgarno sequences for ribosome recognition, and OpaR-binding sites were determined for the five target genes of OpaR, which gave a structural map of the OpaR-dependent promoters. Further computational promoter analysis indicated the above regulatory circuits were shared by several other closely related Vibrios but with slight exceptions.
  
  
  CONCLUSIONS
  This study gave a comprehensive computational and characterization of the direct transcriptional regulation of five target genes, opaR, qrr2-4 and ahpA, by OpaR in V. parahaemolyticus. These characterized regulatory circuits were conserved in V. harveyi and V. parahaemolyticus.
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Yiquan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yefeng
authors.initials: Y
authors.lastname: Qiu
authors.forename: Yafang
authors.initials: Y
authors.lastname: Tan
authors.forename: Zhaobiao
authors.initials: Z
authors.lastname: Guo
authors.forename: Ruifu
authors.initials: R
authors.lastname: Yang
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Zhou
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D053038:Quorum Sensing; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014736:Vibrio parahaemolyticus / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C500454:OpaR protein, Vibrio parahaemolyticus; D014157:Transcription Factors