Influence of Mutations and Phage Infection on E. coli RNA Polymerase

INTRODUCTION RNA polymerase is a complex enzyme consisting of different subunits. It functions in an intimate interaction with template DNA and protein regulatory factors, primarily with sigma factor. In studying these complex interactions, one of the approaches is the investigation of the effects of alterations in RNA polymerase subunits. Therefore we studied the following problems: (1) the influence of phage infection and RNA polymerase mutations on the transcriptional properties of the enzyme; (2) the influence of phage infection and RNA polymerase mutations on the interaction of core enzyme with sigma factor; and (3) the influence of RNA polymerase mutations on the synthesis of its subunits. RESULTS AND DISCUSSION Influence of Phage Infection and RNA Polymerase Mutations on Transcriptional Properties of the Enzyme Phage-induced Changes In the course of T-even phage development, all the phage-induced RNAs are synthesized by bacterial RNA polymerase, which undergoes several changes (Walter, Seifert and Zillig 1968; Travers 1971; Stevens 1972; Horvitz 1973). It is natural to assume that these phage-induced changes of RNA polymerase structure should affect its functional properties. However, the only essential difference between RNA polymerases from infected and uninfected cells observed in vitro is the inability of the former to compete with the latter for template DNA (Khesin et al. 1972). We have therefore compared the transition temperatures of rapidly initiating complex formation for the two enzymes in the rifampicin challenge experiment (Chamberlin 1974; Travers 1974a, b). As can be seen from Figure 1, the transition temperature for the E. coli RNA polymerase...