Reference: Randell JC, et al. (2006) Sequential ATP hydrolysis by Cdc6 and ORC directs loading of the Mcm2-7 helicase. Mol Cell 21(1):29-39

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Abstract


Loading of the Mcm2-7 DNA replicative helicase onto origin-proximal DNA is a critical and tightly regulated event during the initiation of eukaryotic DNA replication. The resulting protein-DNA assembly is called the prereplicative complex (pre-RC), and its formation requires the origin recognition complex (ORC), Cdc6, Cdt1, and ATP. ATP hydrolysis by ORC is required for multiple rounds of Mcm2-7 loading. Here, we investigate the role of ATP hydrolysis by Cdc6 during pre-RC assembly. We find that Cdc6 is an ORC- and origin DNA-dependent ATPase that functions at a step preceding ATP hydrolysis by ORC. Inhibiting Cdc6 ATP hydrolysis stabilizes Cdt1 on origin DNA and prevents Mcm2-7 loading. In contrast, the initial association of Mcm2-7 with the other pre-RC components does not require ATP hydrolysis by Cdc6. Importantly, these coordinated yet distinct functions of ORC and Cdc6 ensure the correct temporal and spatial regulation of pre-RC formation.

Reference Type
Journal Article | Research Support, N.I.H., Extramural | Research Support, Non-U.S. Gov't
Authors
Randell JC, Bowers JL, Rodríguez HK, Bell SP
Primary Lit For
CDC6 | TAH11 | ORC2 | ORC4 | ORC1 | ORC3 | ORC5 | Nuclear origin recognition complex
Additional Lit For
MCM2 | MCM6 | MCM3 | MCM5 | MCM4 | MCM7