CHARACTERIZATION OF A SPORULATION GENE, SPOIVA, INVOLVED IN SPORE COAT MORPHOGENESIS IN BACILLUS-SUBTILIS

Mutations in the spoIVA locus of Bacillus subtilis abolish cortex synthesis and interfere with the synthesis and assembly of the spore coat. We have characterized the cloned spoIVA locus in terms of its physical structure and regulation during sporulation. The locus contains a single gene capable of encoding an acidic protein of 492 amino acids (molecular weight, 55,174). The gene is transcribed from a sigma(E)-dependent promoter soon after the formation of the spore septum. A genetic test indicated that expression of spoIVA is only necessary in the mother cell compartment for the formation of a mature spore. This, together with the phenotypic properties of spoIVA mutations, would be in accord with the hypothesis that sigma(E) is only active after septation and in the mother cell compartment.