[Role of RNA-polymerase in gene activity regulation of E. coli RNA-polymerase mutants with a pleiotropic effect. I. Physiological and biochemical studies].

Four Rifr-mutants of E. coli B/r (rpo B401, rpo B402, rpo B403, rpo B409) which differ from the wild strain in one or more phenotypic properties besides rifampicin resistance were obtained. Transfer of the mutant Rifr-alleles into the parent strain gives the latter all the properties of the mutant. This indicates that the new properties are due to the pleiotropic effect of Rifr-mutations. Biochemical studies of the properties of RNA-polymerases from the mutants and the parent showed that some new properties of the mutants could not be explained by the appearance of analogous properties in the mutant RNA-polymerase itself. They seem to be caused by alteration in functional activity of the mutant enzyme, particulary, alteration of its control properties during transcription. The function of the beta-subunit in genetic transcription is discussed.