Replication of genomes is a complex process that involves the interaction of many proteins and enzyme activities. It initiates at specific locations called origin of replication, which are sites of assembly and binding of protein and enzyme complexes termed origin recognition complex (ORC).

The progress and completion of replication is regulated both in space and in time in such a way that it only starts and terminates at the specific origin and termination sites and at predetermined time points of the cell division cycle. The protein and enzyme complexes responsible for the special and temporal control of the three major stages of initiation, elongation, and termination of DNA replication have been characterized in considerable detail. Biochemical, genetic, and in vitro complementation approaches have been used to reveal common sequence and structural features of the replication machinery such as binding sites for replication proteins, DNA...