[Cloning of DNA fragments containing promoter activity from Streptomyces mycarofaciens 1748].

A DNA fragment containing promoter activity has been cloned from midecamycin producing strain (S. mycarofaciens 1748)., using promoter-probe plasmid vector pIJ486. The molecular size of this fragment was 2.3kb as shown by restriction analysis. A HindIII-HindIII 2.08KB DNA fragment obtained from the original fragment has been analysed by subcloning it into polylinker of vector pIJ486/7 which have opposite direction. The result showed that HindIII-HindIII 2.08kb DNA fragment has promoter activity in both direction. Transformants of plasmid containing this fragment in vector pIJ487 in S. lividans TK24 were resistant to Km in the level of 20mg/ml, but in vector pIJ 486 were resistant to the level of 3mg/ml. It indicated that a rather strong promoter activity region was in the HindIII/XbaI-HindIII direction. BamHI fragments (A-0.79kg, B-0.67kb, C-0.62kb) in 2.08kb DNA fragment have been studied in regards of their promoter activity. The result suggested that A-0.79kb region has the same promoter activity as in HindIII-HindIII 2.08kb DNA fragment.