A constitutively active variant of the quorum-sensing regulator LuxO affects protease production and biofilm formation in Vibrio cholerae.

摘要: Vibrio cholerae normally inhabits aquatic habitats but can cause a severe diarrheal illness in humans. Its arsenal of virulence factors includes secreted hemagglutinin (HA) protease. An HA protease-deficient mutant V. was isolated and designated E7946 mpc. mpc found to contain point mutation the luxO quorum-sensing regulator. In accordance with this finding, exhibits defect quorum sensing. The allele [luxO(Con)] produces protein leucine-to-glutamine substitution at amino acid 104. Transfer luxO(Con) an otherwise wild-type background sufficient eliminate protease expression; conversely, deletion from restored activity. We demonstrate that LuxO(Con) constitutively represses transcription hapR, essential positive regulator Interestingly, strains harboring form enhanced biofilms, biofilm formation does not appear be dependent on reduced expression. Taken together, results confirm role LuxO as central “switch” coordinately regulates virulence-related phenotypes such production formation.