Restriction and modification in Bacillus subtilis: expression of the cloned methyltransferase gene from B. subtilis phage SPR in E. coli and B. subtilis.

Expression of the SPR methyltransferase gene from B. subtilis phage SPR cloned into lambda and SPP1 was studied by analyzing the sensitivity of the hybrid phage DNAs to restriction by the enzymes HaeIII, MspI, and HpaII. The following results were obtained: (1) The genes were expressed both in the homologous (B. subtilis) and heterologous (E. coli) host. (2) The specificity of the expression of the cloned gene was identical to that of the gene in SPR. (3) Expression depended on the orientation of the cloned segment within the vector DNAs suggesting that vector promoters were involved in transcription. The coding strand of the cloned DNA was identified through hybridization with SPR mRNA.