Cloning of midecamycin(MLS)-resistance genes from Streptomyces mycarofaciens, Streptomyces lividans and Streptomyces coelicolor A3(2).

DNA containing genes for midecamycin(Mdm)-resistance was cloned from Streptomyces mycarofaciens ATCC 21454 (mdmA gene), Streptomyces lividans 66 (lrm gene) and Streptomyces coelicolor A3(2). The phenotype imparted to S. lividans and Streptomyces griseofuscus transformants by the cloned DNA segments indicates that they encode an MLS-type of resistance activity. The mdmA and lrm genes could be distinguished by the phenotype they conferred in S. lividans and S. griseofuscus, whereas the S. lividans lrm and S. coelicolor MLS genes appears to be identical on the basis of their restriction maps and behavior in S. lividans and S. griseofuscus. The DNA sequence of a 1.4-kb BamH I DNA fragment containing the mdmA gene indicates the presence of one complete orf whose deduced product exhibits a high similarity to the deduced product of the Streptomyces thermotolerans carB gene and several other bacterial MLS-resistance genes.