sentences:  The isolated CMG helicase and Replisome Progression Complex contain a single Mcm protein ring complex suggesting that the loaded double hexamer of the Mcm proteins at origins might be broken into two single hexameric rings as part of the initiation process, with each Mcm protein complex ring forming the core of a CMG helicase at the two replication forks established from each origin.The full CMG complex is required for DNA unwinding, and the complex of CDC45-Mcm-GINS is the functional DNA helicase in eukaryotic cells.The CMG complex interacts with the replisome through the interaction with Ctf4 and And1 proteins.