title: Molecular characterization of direct target genes and cis-acting consensus recognized by quorum-sensing regulator AphA in Vibrio parahaemolyticus.
abstract: BACKGROUND
  AphA is the master quorum-sensing (QS) regulator operating at low cell density in vibrios. Molecular regulation of target genes by AphA has been characterized in Vibrio harveyi and V. cholerae, but it is still poorly understood in V. parahaemolyticus.
  
  
  RESULTS
  The AphA proteins are extremely conserved in V. parahaemolyticus, Vibrio sp. Ex25, Vibrio sp. EJY3, V. harveyi, V. vulnificus, V. splendidus, V. anguillarum, V. cholerae, and V. furnissii. The above nine AphA orthologs appear to recognize conserved cis-acting DNA signals which can be represented by two consensus constructs, a 20 bp box sequence and a position frequency matrix. V. parahaemolyticus AphA represses the transcription of ahpA, qrr4, and opaR through direct AphA-target promoter DNA association, while it inhibits the qrr2-3 transcription in an indirect manner. Translation and transcription starts, core promoter elements for sigma factor recognition, Shine-Dalgarno sequences for ribosome recognition, and AphA-binding sites (containing corresponding AphA box-like sequences) were determined for the three direct AphA targets ahpA, qrr4, and opaR in V. parahaemolyticus.
  
  
  CONCLUSIONS
  AphA-mediated repression of ahpA, qrr2-4, and opaR was characterized in V. parahaemolyticus by using multiple biochemical and molecular experiments. The computational promoter analysis indicated the conserved mechanism of transcriptional regulation of QS regulator-encoding genes ahpA, qrr4, and opaR in vibrios.
authors.affiliation: Department of Pharmacy, Southwest Hospital, Third Military Medical University, Chongqing, People's Republic of China.
authors.forename: Fengjun
authors.initials: F
authors.lastname: Sun
authors.forename: Yiquan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Yan
authors.forename: Yafang
authors.initials: Y
authors.lastname: Tan
authors.forename: Zhaobiao
authors.initials: Z
authors.lastname: Guo
authors.forename: Jingfu
authors.initials: J
authors.lastname: Qiu
authors.forename: Ruifu
authors.initials: R
authors.lastname: Yang
authors.forename: Peiyuan
authors.initials: P
authors.lastname: Xia
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Zhou
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015169:Colony Count, Microbial; D016384:Consensus Sequence / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D006706:Homeostasis / Q000235:genetics; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics*; D053038:Quorum Sensing / Q000235:genetics*; D012097:Repressor Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics; D014158:Transcription, Genetic; D014736:Vibrio parahaemolyticus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins