Protease production during sporulation of germination mutants of Bacillus subtilis and the cloning of a functional gerE gene.

Early in sporulation, cells of wild-type Bacillus subtilis produce three proteases (b, c and d) with monomeric Mr values of about 65 000, 53 000 and 43 500, and a further protease, e (Mr about 30 000) at the time of coat assembly. An additional protease, f (Mr about 15 000) appears transiently in sporangia at about the time of spore release. Three strains with defective spore coats were examined for alterations in sporulation proteases. A strain carrying the gerE36 mutation produces b, c and d normally, fails to produce e and accumulates f on or in its spores. A strain carrying the spoVIC610 mutation produces normal quantities of proteases b, c and d, but has a reduced amount of proteases e and f. A strain carrying both the gerE36 and the spoVIC610 mutations accumulates neither protease e nor f. The wild-type allele of the gerE gene was cloned in the vector, phage phi 105J9. Complementation tests with the cloned gene showed that the gerE36 mutation is recessive to the wild-type allele.