Cloning of sporulation gene spoOB of Bacillus subtilis and its genetic and biochemical analysis.

A specialized transducing phage carrying a sporulation gene (spoOB) was constructed from Bacillus subtilis temperate phage rho 11 by in vitro and in vivo recombinations. Transformation experiments showed that the spoOB gene resides on a 1.4-megadalton fragment generated by EcoRI endonuclease treatment of the phage deoxyribonucleic acid (DNA). Mutants of this phage which lost transducing activity were isolated and used for genetic complementation tests and the analysis of protein(s) coded by the 1.4-megadalton fragment. The spoOB locus was shown to be composed of one cistron. Sodium dodecyl sulfate-polyacrylamide gel analysis of proteins synthesized in ultraviolet-irradiated cells infected with these phages showed that the 1.4-megadalton fragment codes at least one protein, of molecular weight 39,000, which is synthesized in both vegetative and sporulating cells. A cleavage map of the phage DNA was constructed by use of restriction endonucleases, EcoRI, BamHI, and SalI, and the site of integration of the 1.4-megadalton fragment was determined. Expression and function of the spoOB gene are discussed.