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. Author manuscript; available in PMC: 2018 Oct 6.
Published in final edited form as: Annu Rev Cell Dev Biol. 2017 Aug 11;33:291–318. doi: 10.1146/annurev-cellbio-100616-060447

Figure 1. Overview of DNA replication.

Figure 1

The fork fires as the MCM2-7 helicase proceeds out in a bidirectional fashion from the origin of replication (ORI), unwinding double-stranded DNA as it goes. ORC proteins and cdc6 dissociated from the origin, where they were initially bound to facilitate helicase loading. CDC45 and GINS travel with the MCM2-7 helicase to create the CMG replication complex. The leading strand is synthesized primarily through the actions of DNA polymerase ε. The lagging strand is discontinuously synthesized primarily through the actions of DNA polymerase α and δ. Pol α synthesizes the RNA primer needed to initiate DNA synthesis. The lagging strand is additionally processed by FEN1 and ligase to complete synthesis. The RFC complex is responsible for loading PCNA, which acts as a processivity factor for DNA pol ε and DNA pol δ. Cohesins link the two sister chromatids following passage of the replication fork.