Random and Unique Bacillus subtilis DNA Fragments Carrying a Portion of the RNA Polymerase Genes

Abstract

INTRODUCTION
The size of RNA polymerase (nucleoside triphosphate: RNA nucleotidyltransferase E.C. 2.7.7.6.) indicates that at least 0.27% of the Bacillus genome is devoted to coding for its components. Primarily because of its size and the complexity of its structure, the structure–function relationship between the enzyme and its substrates remains obscure. Control of RNA polymerase synthesis, of its substrate recognition and of the types of structural alteration that can occur in RNA polymerase might be better understood if the genes coding for the enzyme could be purified and characterized.

Until now, the major genetic tool available has been mutational alteration of the enzyme to rifampin (rfm) or streptolydigin (std) resistance. Genetic mapping of such mutations has been successful in locating the markers on the B. subtilis chromosome (Haworth and Brown 1973; Sonenshein et al. 1974).

Recently, purification of the rfm-std region has been achieved (C. Jones and L. R. Brown, in preparation). Estimates of the physical size of the region, its restriction endonuclease sites and the isolation of the genetic markers by physical and enzymatic methods are described elsewhere.

Since high-frequency, specialized transducing phages that will transduce the rfm-std region in B. subtilis have not been isolated, techniques similar to those used to isolate the RNA polymerase β and β′ genes in Escherichia coli could not be used (Kirschbaum and Konrad 1973; Kirschbaum and Scaife 1975; Ikeuchi, Yura and Yamagishi 1975). We report below the characteristics of both random and unique B. subtilis DNA fragments isolated by exploiting the base...