Closing the MCM cycle at replication termination sites.

The initiation of eukaryotic DNA replication is a highly regulated process conserved from yeast to human. The past decade has seen significant advances in understanding how the CMG (Cdc45‐MCM‐GINS) replicative helicase is loaded onto DNA. However, very little was known on how this complex is removed from chromatin at the end of S phase. Two papers in a recent issue of Science [1], [2] show that in yeast and in Xenopus, the CMG complex is unloaded at replication termination sites by an active mechanism involving the polyubiquitylation of Mcm7.