Studies of transcriptional regulation of the Bacillus subtilis developmental gene spoVE

The structural gene of the spoVE locus of Bacillus subtilis was replaced with the promoterless lacZ gene of Escherichia coli. The spoVE::lacZ gene fusion was transferred to the B. subtilis chromosome and beta-galactosidase activity was measured under sporulation conditions. Expression of the hybrid gene could be detected as early as 40 min after the induction of sporulation. Transcription of the spoVE::lacZ gene was dependent on the products of two stage 0 loci, spo0H and spo0K. Mutations in the spoIIA and spoIIG loci did not impede expression of spoVE and, therefore, neither of the sigma factors coded for by these loci seems to be necessary for its transcription. Consequently, the spoVE locus does not seem to be part of the dependent sequence of operons involved in the developmental change, although its protein product is clearly needed for the completion of spore formation.