Expression of Alkaline Protease Gene in Bacillus subtilis Mutants That Lack Positive Regulatory Genes degR, degQ, senS, tenA, and proB

Abstract

In addition to the two-component regulatory system, DegS-DegU, five other genes degR, degQ, senS, tenA, and proB positively regulate the production of Bacillus subtilis exoproteases when they are present on a multicopy plasmid. To study the extent of involvement of these genes in exoprotease production in a single copy state and possible relationship among these genes, strains carrying single or multiple disruption mutations in these loci were constructed, and the expression of aprE'-'lacZ was analyzed. From such studies, the following results were obtained with respect to the regulation of aprE expression. i) Disruption mutations were divided into two groups; one (degQ and degR) significantly reduced aprE expression, while the other (senS, tenA, and proB) had little effect on it. ii) SenS was involved in temporal regulation. iii) The combined effects of dome of the disruption mutations tested were not necessarily additive. iv) The extent of the negative effects generated by the mutations depended on the medium used.