Figure 2.

DNA replication is organized at the nuclear matrix. (a) Replicons are defined in early G1 phase of the cell cycle by attachment of MARs to the nuclear matrix. (b) In late G1, origins of replication (ORIs) are recruited to the nuclear matrix and replication factors assemble at these sites, licensing the chromatin for replication. (c) Once the appropriate mitogenic stimuli have been received, cells enter S phase, at which ORIs become activated. Following initiation of replication at a particular locus, the two identical newly replicated ORIs probably dissociate from the nuclear matrix. Two loops of replicated DNA gradually emerge (shown in blue), while the yet-to-be replicated DNA of the replicon moves through the replication factory. (d) At the end of S phase, the replication machinery is dismantled. Adapted from [71].