Cloning in Bacillus subtilis of temperature-dependent promoter fragments from Bacillus stearothermophilus and Bacillus subtilis

Using promoter-probe plasmids, more than 200 promoter-containing fragments from Bacillus stearothermophilus and Bacillus subtilis were cloned in B. subtilis. Among these, 15 promoter fragments were highly temperature-dependent in activity compared to the promoter sequence (TTGAAA for the −35 region, TATAAT for the −10 region) of the amylase gene, amyT, from B. stearothermophilus. Some fragments exhibited higher promoter activities at elevated temperature (48°C), others showed higher activities at lower temperature (30°C). Active promoter fragments at higher and lower temperatures were obtained mainly from the thermophile (B. stearothermophilus) and the mesophile (B. subtilis), respectively. A promoter fragment active at high temperature was sequenced, and the feature of the putative promoter region was discussed.