Effects of major spore-specific DNA binding proteins on Bacillus subtilis sporulation and spore properties

Sporulation of a Bacillus subtilis strain (termed alpha (-) beta (-)) lacking the majority of the alpha/beta -type small, acid-soluble spore proteins (SASP) that are synthesized in the developing forespore and saturate spore DNA exhibited a number of differences from that of the wild-type strain, including delayed forespore accumulation of dipicolinic acid, overexpression of forespore-specific genes, and delayed expression of at least one mother cell-specific gene turned on late in sporulation, although genes turned on earlier in the mother cell were expressed normally in alpha (-) beta (-) strains. The sporulation defects in alpha (-) beta (-) strains were corrected by synthesis of chromosome-saturating levels of either of two wild-type, alpha/beta -type SASP but not by a mutant SASP that binds DNA poorly. Spores from alpha (-) beta (-) strains also exhibited less glutaraldehyde resistance and slower outgrowth than did wild-type spores, but at least some of these defects in alpha (-) beta (-) spores were abolished by the synthesis of normal levels of alpha/beta -type SASP, These results indicate that alpha/beta -type SASP may well have global effects on gene expression during sporulation and spore outgrowth.