Mutant RNA polymerase of Escherichia coli terminates transcription in strains making defective rho factor.

Abstract

A rifampicin-resistant mutant of E. coli RNA polymerase that restores transcription termination in strains with a defective rho protein was isolated. In such strains, the mutant RNA polymerase terminates transcription at normally rho-dependent sites at the end of the trp operon, in bacteriophage .lambda., and within the lac operon. A strain with this mutant RNA polymerase remains viable with an amber mutation in rho, but a strain with wild-type RNA polymerase does not. The mutant RNA polymerase can probably terminate transcription at normally rho-dependent sites in the absence of rho.