[Autonomous replication of plasmid pBR322 containing a mitochondrial DNA fragment of animal origin in the cells of bacteria mutant for DNA-polymerase I].

Escherichia coli K-12 p108(polA6), p3478(polA1) and KS55(polA12 ts) strains were transformed by recombinant DNA consisting of pBR322 plasmid and BamHI fragment A of rat liver mtDNA containing the origin. For all the strains tested, it was shown that the cells containing hybrid molecules were able to grow on the selective medium under the conditions when pBR322 replicon is not functional. The existence of mtDNA insertion in hybrid molecules was confirmed by electrophoresis and colony hybridization with the 125I-mtDNA. Thus, the ability of a vector containing plasmid replicon and the mitochondrial origin to replicate under the conditions nonpermissive for stable replication of plasmid DNA alone, was demonstrated for the first time.