THE HEMIMETHYLATED REPLICATION ORIGIN OF ESCHERICHIA-COLI CAN BE INITIATED INVITRO

Unmethylated, fully methylated, and hemimethylated oriC-containing plasmids were assayed as substrates for DNA replication in vitro by using a system reconstituted with pure proteins. In contrast to the in vivo situation, all three substrates were initiated efficiently; the fully methylated plasmid was about twice as active as the other two.