Mutations in toxR and toxS that separate transcriptional activation from DNA binding at the cholera toxin gene promoter.

ABSTRACT: ToxR and ToxS are integral membrane proteins that activate the transcription of virulence genes in Vibrio cholerae. ToxR can be separated into three different domains: an N-terminal cytoplasmic DNA binding domain, a central transmembrane domain, and a C-terminal periplasmic domain. ToxS is thought to enhance ToxR-mediated transcriptional activation through a periplasmic interaction. By P22 challenge phage selection for DNA binding, in combination with a screen for cholera toxin gene transcription, 12 toxR and toxS positive control mutants producing variant ToxR proteins from the toxRS operon that bind to the cholera toxin promoter but that fail to activate transcription were isolated. One mutation in toxR specifies an E82K change in the predicted helix-loop-helix DNA binding domain and des

SUBMITTER: Pfau JD 

PROVIDER: S-EPMC107489 | biostudies-literature | 1998 Sep

REPOSITORIES: biostudies-literature