MOLECULAR-GENETIC AND PHENOTYPICAL ANALYSIS OF THE GERM SPORE GERMINATION GENE OF BACILLUS-SUBTILIS-168

The gerM gene, encoding a single product of 22.5 kDa, has been identif ied by subcloning and sequencing of DNA recovered from adjacent to a T n917 insertion. The gene product has a potential lipoprotein signal se quence, but otherwise has no homology to known sequences. Spores of th e gerM mutant were more heat sensitive than wild-type, but their dipic olinic acid content was normal. The level of cortical peptidoglycan in mutant spores is also normal but release at germination of hexosamine -containing fragments, the breakdown products of cortex degradation, i s less complete than wild-type. The sporulation, resistance and germin ation phenotypes of the gerM mutant would be consistent with the gene product having a role, either directly or indirectly, in peptidoglycan synthesis during sporulation.