Ribonuclease from Bacillus thuringiensis var. subtoxicus: Gene structure and regulation of biosynthesis

The gene for extracellular guanyl-specific ribonuclease of Bacillus thuring iensis var. subtoxicus (RNase Bth), a close homologue of the B. intermedius RNase (binase), was completely sequenced. Analysis of nucleotide sequences in the regions adjoining RNase genes revealed an identical organization of the chromosomal loci of RNase Bth and binase. Growth Characteristics of th e Bacillus thuringiensis var, subtoxicus strain and its synthesis of RNase were studied. It was shown that the exogenous inorganic phosphate inhibits the biosynthesis of RNase. At the same time, actinomycin D in low doses sti mulates the enzyme synthesis. Comparative analysis of the influence of inor ganic phosphate and actinomycin D on the biosynthesis of RNAse Bth and bina se suggests a possibility of coincidence of regulatory pathways of synthesi s of these enzymes.