Based on studies in budding yeast, after CDT1-mediated loading of the MCM2-7 complex to CDC6 bound to the ORC(1-6) complex at the replication origin and ATP-dependent release of CDT1, another complex of CDT1 and MCM2-7 is loaded, resulting in the formation of the salt-stable double hexamer of MCM2-7 (Fernández-Cid et al. 2013). MCM2-7 double hexamers are connected head-to-head via their N-terminal rings. DNA runs through a central channel in the double hexamer (Remus et al. 2009). In a study using human proteins, it was suggested that geminin inhibits the formation of salt-resistant pre-replicative complexes (Wu et al. 2014), possibly by interfering with CDT1-mediated loading of the second MCM2-7 hexamer.