Regulation of sigL expression by the catabolite control protein CcpA involves a roadblock mechanism in Bacillus subtilis: potential connection between carbon and nitrogen metabolism.

A catabolite-responsive element (CRE), a binding site for the CcpA transcription factor, was identified within the sigL structural gene encoding sigma(L) in Bacillus subtilis. We show that CcpA binds to this CRE to regulate sigL expression by a "roadblock" mechanism and that this mechanism in part accounts for catabolite repression of sigma(L)-directed levD operon expression.