We have determined the nucleotide sequence of a 1496 bp stretch of Bacillus subtilis chromosome that complements the gerE36 mutation. The sequence contains three open reading frames. One of these is part of the sdhC gene, the other two, whose functions are unknown, are capable of encoding proteins with Mr values of approximately 17,000 and 8500. The use of integrational plasmids to delimit the gerE transcriptional unit shows that the gerE locus consists of one gene, which encodes a polypeptide of 74 amino acid residues and which is switched on after t3 during sporulation of wild-type B. subtilis 168.