Localization of an origin of replication inCorynebacterium diphtheriaebroad host range plasmid pNG2 that also functions inEscherichia coli

Subcloning and protoplast transformation studies identified a 2.6 kb fragment of Corynebacteriumdiphtheriae plasmid pNG2 which contains an origin of replication (oriR). Molecular combination of the 2.6 kb oriR cartridge with Escherichia coli plasmid pUC18CmR enabled the E. coli cloning vector to replicate within several species of Corynebacterium host cells. A 2.6 kb plasmid formed from the oriR cartridge alone is capable of replicating in E. coli. This suggests that a single origin could be used in vectors shuttling between Corynebacterium spp. and E. coli.