Open AccessQuorum Sensing Negatively Regulates Hemolysin Transcriptionally and Posttranslationally in Vibrio cholerae
Author(s) -
Amy M. Tsou,
Jun Zhu
Publication year - 2010
Publication title -
infection and immunity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.508
H-Index - 220
eISSN - 1070-6313
pISSN - 0019-9567
DOI - 10.1128/iai.00590-09
Subject(s) - vibrio cholerae , quorum sensing , virulence , biology , cholera toxin , hemolysin , microbiology and biotechnology , pilus , virulence factor , transcriptional regulation , transcription factor , gene , bacteria , genetics
Recent work has shown that in addition to cholera toxin (CT) and the toxin-coregulated pilus (TCP), other cytotoxic proteins inVibrio cholerae also cause disease symptoms, and this is particularly evident in strains lacking CT. One such protein is the hemolysin encoded byhlyA . Here we show that, like CT and TCP, HlyA is repressed by the quorum-sensing-regulated transcription factor HapR. This repression occurs on two levels: one at the transcriptional level that is independent of the metalloprotease HapA and one at the posttranslational level that is mediated by HapA. The transcriptional regulation is significantly more apparent on solid media than in liquid cultures. This is the first time that hemolysis has been shown to be directly regulated by quorum sensing inV. cholerae , and it is interesting that, like other virulence factors, HlyA is also repressed by HapR, which is expressed late in infection.