MCM9 binds Cdt1 and is required for the assembly of prereplication complexes.
Prereplication complexes (pre-RCs) define potential origins of DNA replication and allow the recruitment of the replicative DNA helicase MCM2-7. Here, we characterize MCM9, a member of the MCM2-8 family. We demonstrate that MCM9 binds to chromatin in an ORC-dependent manner and is required for the recruitment of the MCM2-7 helicase onto chromatin. Its depletion leads to a block in pre-RC assembly, as well as DNA replication inhibition. We show that MCM9 forms a stable complex with the licensing factor Cdt1, preventing an excess of geminin on chromatin during the licensing reaction. Our data suggest that MCM9 is an essential activating linker between Cdt1 and the MCM2-7 complex, required for loading the MCM2-7 helicase onto DNA replication origins. Thus, Cdt1, with its two opposing regulatory binding factors MCM9 and geminin, appears to be a major platform on the pre-RC to integrate cell-cycle signals.
Lutzmann
Malik
M
Institute of Human Genetics, CNRS, 141 rue de la Cardonille, 34396 Montpellier, France.
Méchali
Marcel
M
D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D064248:Geminin; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D064110:Minichromosome Maintenance Proteins; D008970:Molecular Weight; D051738:Origin Recognition Complex / Q000378:metabolism; D011485:Protein Binding; D014714:Vertebrates / Q000378:metabolism; D014981:Xenopus; D029867:Xenopus Proteins / Q000378:metabolism*
C467199:CDT1 protein, human; C406819:Cdt1 protein, Xenopus; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; C577998:GMNN protein, Xenopus; D064248:Geminin; D051738:Origin Recognition Complex; D029867:Xenopus Proteins; C507165:MCM9 protein, Xenopus; C501931:MCM9 protein, human; D064110:Minichromosome Maintenance Proteins