EFFECTS OF THE SINR AND DEGU32 (HY) MUTATIONS ON THE REGULATION OF THE APRE GENE IN BACILLUS-SUBTILIS

The aprE gene of Bacillus subtilis codes for the serine alkaline prote ase known as subtilisin. Its expression is regulated by a complex netw ork of activators and repressors that includes the products of hpr, de gU and sinR. In order to understand the effect of these gene products on subtilisin expression, strains carrying combinations of the degU32( Hy), hpr2 and sinR null mutations, were constructed. We found that in all the genetic backgrounds tested, the sinR null mutation decreased a prE expression. Also, by measuring alkaline phosphatase synthesis and the formation of heat-resistant spores, as indicators of sporulation, we found that some of the mutant strains showed alterations in the spo rulation process. These results suggest that these alterations are par tially responsible for some of the observed changes in aprE expression .