New phage-SPO1-induced polypeptides associated with Bacillus subtilis RNA polymerase

Abstract

RNA polymerase was precipitated from extracts of Bacillus subtilis infected with phage SP01 by antiserum prepared against core RNA polymerase. As shown by sodium dodecyl sulfate gel electrophoresis, the precipitates contained at least five new polypeptides not present in uninfected bacteria, in addition to the known subunits of RNA polymerase. The molecular weights of these polypeptides are (1) 85,000; (II) 40,000; (III) 28,000; (IV) 25,000; and (V) 23,000. Four of the polypeptides (I, III, IV, and V) co-purified with RNA polymerase through gel filtration and phosphocellulose chromatography. A pulse-chase experiment indicated that all five polypeptides are synthesized de novo after infection. The synthesis of polypeptides II, III, and IV commences almost immediately after infection, while polypeptides I and V first appear several minutes later. A sus mutant blocked early in transcription, susF21 [Fujita, et al. (1971) J. Mol. Biol. 57, 301-317] failed to induce polypeptides I, IV, and V, while two other mutants, susF4 and susF14, blocked late in transcription both failed only to induce polypeptide V.