Figure 1
From: Emerging players in the initiation of eukaryotic DNA replication
Emerging players in the assembly of pre-replicative complex (pre-RC). The classical model of pre-RC assembly involves the ordered loading of ORC, Cdc6, Cdt1 and MCM2-7 onto replication origins. The Cdt1 inhibitor, Geminin associates with Cdt1 outside G1 phase of the cell cycle and prevents the re-assembly of pre-RC. Several ORC interacting proteins (ORCA/LRWD1, 14-3-3) and non-coding RNAs (G-quadruplex RNA, Y RNA) have been found to be involved in regulating ORC binding to origins. MCM8 interacts with Cdc6 and is required for Cdc6 chromatin loading. HBO1 and MCM9 facilitate Cdt1 activity by antagonizing Geminin and modulating Cdt1-Geminin stoichiometry respectively. In addition, HOX and Idas interacts with Geminin and may control Geminin’s dual functions in proliferation-differentiation determination.