Affiliation:
1. Department of Microbiology, Dartmouth Medical School, Hanover, New Hampshire 03755
Abstract
ABSTRACT
We describe here a new member of the LysR family of transcriptional regulators, AphB, which is required for activation of the
Vibrio cholerae
ToxR virulence cascade. AphB activates the transcription of the
tcpPH
operon in response to environmental stimuli, and this process requires cooperation with a second protein, AphA. The expression of neither
aphA
or
aphB
is strongly regulated by environmental stimuli, raising the possibility that the activities of the proteins themselves may be influenced under various conditions. Strains of the El Tor biotype of
V. cholerae
typically exhibit lower expression of ToxR-regulated virulence genes in vitro than classical strains and require specialized culture conditions (AKI medium) to induce high-level expression. We show here that expression of
aphB
from the
tac
promoter in El Tor biotype strains dramatically increases virulence gene expression to levels similar to those observed in classical strains under all growth conditions examined. These results suggest that AphB plays a role in the differential regulation of virulence genes between the two disease-causing biotypes.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference38 articles.
1. Organization of tcp, acf, and toxT genes within a ToxT-dependent operon;Brown R. C.;Mol. Microbiol.,1995
2. Phase variation in tcpH modulates expression of the ToxR regulon in Vibrio cholerae;Carroll P. A.;Mol. Microbiol.,1997
3. A branch in the ToxR regulatory cascade of
Vibrio cholerae
revealed by characterization of
toxT
mutant strains
4. Single amino acid substitutions in the N-terminus of Vibrio cholerae TcpA affect colonization, autoagglutination, and serum resistance;Chiang S. L.;Mol. Microbiol.,1995
5. Periplasmic interaction between two membrane regulatory proteins, ToxR and ToxS, results in signal transduction and transcriptional activation;DiRita V. J.;Cell,1991
Cited by
170 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献