Once-per-cell cycle replication is regulated through the assembly onto chromatin of
multisubunit protein complexes that license DNA for a further round of replication. Licensing
consists of the loading of the hexameric MCM2–7 complex onto chromatin during G 1 phase
and is dependent on the licensing factor Cdt1. In vitro experiments have suggested a two-
step binding mode for minichromosome maintenance (MCM) proteins, with transient initial
interactions converted to stable chromatin loading. Here, we assess MCM loading in live …