Evidence in vivo for autogenous control of the cyclic AMP receptor protein gene (crp) in Escherichia coli by divergent RNA

Control of crp expression in vivo was studied by using the cloned crp gene. The synthesis of the product of this gene, cyclic AMP (cAMP) receptor protein (CRP), was strongly reduced by exogenous cAMP. This regulation was completely abolished by the inactivation of a divergent promoter located within the crp promoter region. These data are consistent with our in vitro studies (Okamoto and Freundlich, Proc.Natl. Acad. Sci. USA 83:5000-5004, 1986), which showed that crp autoregulation is due to the inhibition of crp transcription by divergent (antisense) RNA produced by cAMP-CRP activation of the divergent promoter.