[Cloning and expression of Streptomyces lividans promoters]

BamHI restriction fragments from Streptomyces lividans TK24 chromosome DNA have been cloned into BamHI site of promoter probe plasmid pIJ486. Transformants were selected on the medium containing 5 micrograms/ml of neomycin. Four recombinant plasmids pMG1(10.6 kb), pMG40(7.6 kb), pMG50(10.8 kb) and pMG88(7.92 kb), were found and designated respectively. The inserted fragments in pMG40 and pMG50 were reduced to 0.78kb and 2.2 kb by BglII digestion and rejoining. The different levels of neomycin and kanamycin resistance of these recombinant plasmids were determined. The results revealed that pMG50-25 showed a high level of neomycin resistance (90 micrograms/ml) and kanamycin resistance (500 micrograms/ml).