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- Title
Direct regulation of the natural competence regulator gene tfoX by cyclic AMP (cAMP) and cAMP receptor protein (CRP) in Vibrios.
- Authors
Rui Wu; Meng Zhao; Jing Li; He Gao; Biao Kan; Weili Liang
- 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 tfoXVC was restored by trans-complementation of crp in Δcrp and by exogenous cAMP in Δcya. 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 tfoXVC promoter was demonstrated by EMSA assays. Additionally, the transcriptional start site (TSS) of tfoXVF 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.
- Subjects
REGULATOR genes; CYCLIC adenylic acid; VIBRIO; GENETIC transcription; MESSENGER RNA
- Publication
Scientific Reports, 2015, p1
- ISSN
2045-2322
- Publication type
Article
- DOI
10.1038/srep14921