Premium
Molecular basis for the differential expression of the global regulator VieA in Vibrio cholerae biotypes directed by H‐NS, LeuO and quorum sensing
Author(s) -
Ayala Julio C.,
Wang Hongxia,
Benitez Jorge A.,
Silva Anisia J.
Publication year - 2018
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13884
Subject(s) - vibrio cholerae , biology , operon , quorum sensing , el tor , transcription (linguistics) , promoter , genetics , lac operon , biofilm , regulator , stringent response , gene , microbiology and biotechnology , gene expression , bacteria , escherichia coli , linguistics , philosophy
Summary VieA is a cyclic diguanylate phosphodiesterase that modulates biofilm development and motility in Vibrio cholerae O1 of the classical biotype. vieA is part of an operon encoding the VieSAB signal transduction pathway that is nearly silent in V. cholerae of the El Tor biotype. A DNA pull‐down assay for proteins interacting with the vieSAB promoter identified the LysR‐type regulator LeuO. We show that in classical biotype V. cholerae , LeuO cooperates with the nucleoid‐associated protein H‐NS to repress vieSAB transcription. LeuO and H‐NS interacted with the vieSAB promoter of both biotypes with similar affinities and protected overlapping DNA sequences. H‐NS was expressed at similar levels in both cholera biotypes. In contrast, El Tor biotype strains expressed negligible LeuO under identical conditions. In El Tor biotype vibrios, transcription of vieSAB is repressed by the quorum sensing regulator HapR, which is absent in classical biotype strains. Restoring HapR expression in classical biotype V. cholerae repressed vieSAB transcription by binding to its promoter. We propose that double locking of the vieSAB promoter by H‐NS and HapR in the El Tor biotype prior to the cessation of exponential growth results in a more pronounced decline in VieA specific activity compared to the classical biotype.