FIG. 8.

A possible model for the involvement of cellular replication proteins at the MRE. LANA binds to its cognate sequence through its carboxyl terminus, which has also been shown to bind to the ORCs. The binding of ORCs to LANA most probably allows association of ORCs with the DNA element in close proximity to the RE. LANA-bound ORCs may serve as a launching pad for the loading of other cellular replication proteins, including cdc6, Cdt1, and MCMs. Cellular geminin, which is expressed during S phase, associates with Cdt1 and thus prevents relicensing of the TR origins to prevent overreplication, a mechanism similar to the control of replication of host genomic DNA.