CLONED GENE ENCODING THE DELTA SUBUNIT OF BACILLUS-SUBTILIS RNA-POLYMERASE

Core RNA polymerase and several forms of RNA polymerase holoenzyme from Bacillus subtilis are found in association with a 21 500-kDa polypeptide called delta (.delta.). We have cloned the structural gene (rpoE) for .delta. by using as a hybridization probe a synthetic oligodeoxynucleotide that was designed on the basis of a partial NH2-terminal amino acid (aa) sequence of purified .delta. protein. The rpoE gene was found to encode a 173-aa polypeptide of a predicted Mr of 20,400. Genetic and physical mapping experiments placed rpoE at 325.degree. on the B. subtilis chromosome and established the gene order ropE-ctrA-spo0F. The .delta. subunit is known to enhance the specificity of transcription in vitro by bacterial and phage SPO1-modified forms of polymerase, but replacement of rpoE by an in vitro-constructed deletion-mutated gene was found not to impair viability sporulation, or the growth of phage SPO1.