IDENTIFICATION AND CHARACTERIZATION OF THE BACILLUS-SUBTILIS SPOIIP LOCUS

We have identified an additional sporulation gene, named spoIIP, in th e region of the Bacillus subtilis chromosome located immediately downs tream of the gpr gene (227 degrees on the genetic map), A null mutatio n of spoIIP arrests sporulation at an early stage of engulfment (stage IIii), a phenotype similar to that already described for spoIID and s poIIM mutants, This gene encodes a 401-residue polypeptide, which is p redicted to be anchored in the membrane, most of the protein being loc alized outside the cytoplasm, The spoIIP gene is transcribed from a pr omoter located in the interval between the gpr and the spoIIP reading frames. This promoter has the structural and genetic characteristics o f a sigma(E)-dependent promoter. Transcription of spoIIP is abolished by a mutation in spoIIGB, the gene encoding sigma(E), and can be induc ed during exponential growth in cells engineered to produce an active form of sigma(E) :Plasmid integration-excision experiments leading to the formation of genetic mosaics during sporulation indicate that as w ith SpoIID and SpoIIM, SpoIIP is required only in the mother cell, Dis ruption of spoIIP had little or no effect on the expression of sigma(F )- and sigma(E)-controlled regulons but inhibited transcription from s igma(G)-dependent promoters and abolished transcription from promoters under the control of sigma(K), We propose that, together with SpoIID and SpoIIM, the SpoIIP protein is involved in the dissolution of the p eptidoglycan located in the sporulation septum.