Quorum-sensing regulators control virulence gene expression in Vibrio cholerae
AUTOR(ES)
Zhu, Jun
FONTE
The National Academy of Sciences
RESUMO
The production of virulence factors including cholera toxin and the toxin-coregulated pilus in the human pathogen Vibrio cholerae is strongly influenced by environmental conditions. The well-characterized ToxR signal transduction cascade is responsible for sensing and integrating the environmental information and controlling the virulence regulon. We show here that, in addition to the known components of the ToxR signaling circuit, quorum-sensing regulators are involved in regulation of V. cholerae virulence. We focused on the regulators LuxO and HapR because homologues of these two proteins control quorum sensing in the closely related luminous marine bacterium Vibrio harveyi. Using an infant mouse model, we found that a luxO mutant is severely defective in colonization of the small intestine. Gene arrays were used to profile transcription in the V. cholerae wild type and the luxO mutant. These studies revealed that the ToxR regulon is repressed in the luxO mutant, and that this effect is mediated by another negative regulator, HapR. We show that LuxO represses hapR expression early in log-phase growth, and constitutive expression of hapR blocks ToxR-regulon expression. Additionally, LuxO and HapR regulate a variety of other cellular processes including motility, protease production, and biofilm formation. Together these data suggest a role for quorum sensing in modulating expression of blocks of virulence genes in a reciprocal fashion in vivo.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=122484Documentos Relacionados
- Three Parallel Quorum-Sensing Systems Regulate Gene Expression in Vibrio harveyi†
- Quorum-Sensing Signals and Quorum-Sensing Genes in Burkholderia vietnamiensis
- Pseudomonas aeruginosa Quorum-Sensing Systems May Control Virulence Factor Expression in the Lungs of Patients with Cystic Fibrosis
- Genetic control of quorum-sensing signal turnover in Agrobacterium tumefaciens
- Cross-species induction of luminescence in the quorum-sensing bacterium Vibrio harveyi.