DNA replication of plasmids from gram-positive bacteria in Bacillus subtilis. Plasmid pUB110 as a model system.

The small high copy plasmids from gram-positive bacteria like pUB110 replicate via an asymmetric rolling circle mechanism. On the based of several criteria those plasmids could be subdivided in four different families. By analysing pUB110 replication in B. subtilis as a model system we have obtained information on the way by which initiation, elongation and termination in replication is accomplished in B. subtilis.