recE-Dspendent Gene Amplification Induced by a Tunicamycin-resistant Mutation (tmrA7) in Bacillus subtilis

Abstract

A recombinant Bacillus subtilis phage, ρ11-AA248, contains the tmrA7-amyR2-amyE⁺-tmrB⁺-aroI⁺ region of the B. subtilis N7 chromosome on a 22.4kb DNA fragment. The amyE⁺-tmrB⁺ gene region in the phage genome of the B. subtilis 207-21 transductants by ρ11-AA248 was amplified to approximately 10 copies after cultivation in the presence of tunicamycin (10 μg/ml) and to two copies without tunicamycin. The amplification of the gene region caused hyper-production of extracellular α-amylase. In contrast, no amplification of the gene region was detected in the transductants of B. subtilis 207-25, a recE-deficient derivative of 207-21 strain.