Gene Amplification of the amy E-tmrB Region in Bacillus subtilis

Abstract

Bacillus subtilis B7, a tmrA mutant, shows both tunicamycin resistance and α-amylase hyperproductivity. The tmrA characters can be transferred simultaneously to recipient cells by DNA-mediated transformation. We found a typical gene amplification phenomenon in the tmrA transformants and B7 strain. The amplified unit, 16.3kb in size, covers α-amylase structural gene amyE to another tunicamycin resistance gene tmrB, which is located 9kb downstream of the amyE gene. About 10 repeating units are supposed to be tandemly repeated in the transformants. Amplification of the wild amyE and tmrB genes could be the cause of the α-amylase hyperproductivity and tunicamycin resistance of the tmrA transformants and B7 strain.