Concerted Loading of Mcm2-7 Double Hexamers Around DNA during DNA Replication Origin Licensing

By D. Remus, F. Beuron, G. Tolun, J. Griffith, E. Morris, J. Diffley. Cell, 2009

718 citations recorded by the source corpus.

The licensing of eukaryotic DNA replication origins, which ensures once per cell cycle replication, involves the loading of six related minichromosome maintenance proteins (Mcm2-7) into prereplicative complexes (pre-RCs). Mcm2-7 forms the core of the replicative DNA helicase, which is inactive in the pre-RC. The ATP-dependent Mcm2-7 loading reaction requires the Origin Recognition Complex (ORC), Cdc6 and Cdt1. We have reconstituted Mcm2-7 loading with purified budding yeast proteins. Using biochemical approaches and electron microscopy, we show that single heptamers of Cdt1·Mcm2-7 are loaded cooperatively into stable, head-to-head Mcm2-7 double hexamers connected via N-terminal rings. DNA runs through a central channel in the double hexamer, and, once loaded, Mcm2-7 can slide passively along double-stranded DNA. Our work has significant implications for understanding how eukaryotic DNA replication origins are chosen and licensed, how replisomes assemble during initiation and how unwinding occurs during DNA replication.

Subfields: Cell Biology, Genetics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/ba08d578c5bed5cde44286c3c8740d20d3ce88c1

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In Molecular Biology

1. Yuichiro Saito
2. Masato T. Kanemaki

Citations in the corpus

• DNSN-1 recruits GINS for CMG helicase assembly during DNA replication initiation in C. elegans (2023, neutral): “Two such rings are loaded in a concerted fashion around double-stranded DNA at replication origins during G1-phase (Figure S1, step 1), thereby forming a head-to-head double hexamer of Mcm2-7 that lacks helicase activity (13, 14).”
• MCMBP promotes the assembly of the MCM2–7 hetero-hexamer to ensure robust DNA replication in human cells (2022, background): “In the late M to G1 phase, the MCM2–7 hexamer is loaded onto replication origins bound with ORC1–6, to form pre- replicative complexes (pre- RCs) in which the loaded MCM2–7 makes a head- tohead doublehexamer complex (Bleichert et al., 2017; Evrin et al., 2009; Remus et al., 2009).”
• Activation of the MCM2-7 Helicase by Association with Cdc45 and GINS proteins (2010, background): “What information do we now have regarding the molecular disposition of the MCMs on duplex in the pre-RC? Recent work has revealed that ORC, Cdc6, and Cdt1 can load cooperatively onto DNA two copies of the MCM ring where the duplex passes through the double hexamer (Evrin et al., 2009; Remus et al., ”
• DNA interstrand crosslink repair and cancer (2011, neutral): “The replication of DNA requires DNA unwinding ahead of the DNA polymerase, which is achieved by the helicase functions of the minichromosome maintenance complex (MCM2–7”