[Essential region for self-replication of Coryneform bacteria plasmid pXZ10145].

A pTSK series of recombinant plasmids were constructed by cloning DNA fragments of pXZ10145 or its deleted deriviate pATN65 into plasmid vector pACYC177 of E. coli. Experiment results of Coryneform bacteria transformation with these pTSK plasmids allowed us to localize the essential region for self-replication on plasmid pXZ10145. The minimal replication region of the pXZ10145 was located on a 1.2kb Nael-Nrul DNA fragment in which only one open reading frame was found. This ORF was believed to be encoded a trans-acting replication factor. The replication origin (oriV) was locate on a 0.3kb NaeI-SalI fragment which was within the ORF region.