title: Direct regulation of the natural competence regulator gene tfoX by cyclic AMP (cAMP) and cAMP receptor protein (CRP) in Vibrios.
abstract: TfoX (Sxy) and CRP are two important competence activators. The link between tfoX and CRP has been shown in H. influenza but lacking evidence of direct interaction. Recently a Sxy-dependent CRP (CRP-S) site autoregulating Sxy was reported in E. coli. Here, we show that the cAMP-CRP complex transcriptionally regulates tfoX expression through multiple canonical CRP (CRP-N) sites in Vibrios. This conclusion is supported by an analysis of the tfoX mRNA levels and tfoX transcriptional reporter fusions. The reduced expression of tfoX(VC) was restored by trans-complementation of crp in ∆crp and by exogenous cAMP in ∆cya. A promoter deletion analysis and the site-directed mutagenesis of the putative CRP-N sites revealed the presence of two functional CRP-N sites. The direct binding of cAMP-CRP to the tfoX(VC)promoter was demonstrated by EMSA assays. Additionally, the transcriptional start site (TSS) of tfoX(VF) in V. fluvialis was determined, and -10/-35 regions were predicted. Further comparison of the tfoX promoter in Vibrios revealed the existence of similar -10 motifs and putative CRP-N sites, indicating the conserved mechanism of CRP regulation on tfoX. Our study demonstrates the direct binding of the cAMP-CRP complex to tfoX promoter, and broadens the understanding of the molecular mechanism regulating tfoX in Vibrios.
authors.affiliation: National Institute for Communicable Disease Control and Prevention, and State Key Laboratory of Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, Changping, Beijing, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.affiliation: National Institute for Communicable Disease Control and Prevention, and State Key Laboratory of Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, Changping, Beijing, People's Republic of China.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhao
authors.affiliation: National Institute for Communicable Disease Control and Prevention, and State Key Laboratory of Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, Changping, Beijing, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: National Institute for Communicable Disease Control and Prevention, and State Key Laboratory of Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, Changping, Beijing, People's Republic of China.
authors.forename: He
authors.initials: H
authors.lastname: Gao
authors.affiliation: National Institute for Communicable Disease Control and Prevention, and State Key Laboratory of Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, Changping, Beijing, People's Republic of China.|Collaborative Innovation Centre for Diagnosis and Treatment of Infectious Diseases, Hangzhou, People's Republic of China.
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
authors.affiliation: National Institute for Communicable Disease Control and Prevention, and State Key Laboratory of Infectious Disease Prevention and Control, Chinese Centre for Disease Control and Prevention, Changping, Beijing, People's Republic of China.|Collaborative Innovation Centre for Diagnosis and Treatment of Infectious Diseases, Hangzhou, People's Republic of China.
authors.forename: Weili
authors.initials: W
authors.lastname: Liang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D000242:Cyclic AMP / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein / Q000235:genetics / Q000378:metabolism*; D061269:DNA Transformation Competence / Q000235:genetics*; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic / Q000235:genetics; D014733:Vibrio / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002373:Cyclic AMP Receptor Protein; D000242:Cyclic AMP