Open AccessIdentification of toxS, a regulatory gene whose product enhances toxR-mediated activation of the cholera toxin promoter
Author(s) -
Virginia L Miller,
Victor J. DiRita,
John J. Mekalanos
Publication year - 1989
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.171.3.1288-1293.1989
Subject(s) - operon , biology , vibrio cholerae , cholera toxin , gene , activator (genetics) , regulator gene , gene product , gal operon , plasmid , promoter , genetics , l arabinose operon , regulation of gene expression , microbiology and biotechnology , regulatory sequence , escherichia coli , gene expression , bacteria
We describe the cloning of the toxS gene from Vibrio cholerae E1 Tor strain E7946. This gene lies downstream from the toxR gene, which encodes the transcriptional activator for the cholera toxin (ctx) operon in V. cholerae. We show that ToxS acts in conjunction with ToxR to activate expression of the ctx operon in Escherichia coli. The classical strain 569B, which is attenuated for virulance but which synthesizes high levels of cholera toxin in vitro, carries a deletion of 1.2 kilobase pairs of DNA, downstream from the toxR gene, which removes toxS. We present evidence that toxS is the downstream gene in an operon with toxR.