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#Cdt1

2 public questions tagged with this topic.

Cell Cycle Regulation

What is the function of Cdc6 and Cdt1 in DNA replication?

Pre-replication complex formation establishes replication competence before S phase, separating helicase loading from activation. Origin recognition complex ORC marks replication origins throughout cell cycle at AT-rich sequences. In late mitosis and early G1 when CDK activity minimal due to APC/C-Cdh1 mediated cyclin degradation, AAA+ ATPase Cdc6 binds ORC and recruits chaperone Cdt1 bound to single hexamer of MCM2-7 helicase. ATP hydrolysis by Cdc6 and ORC opens MCM ring, allowing encirclement of double-stranded DNA and formation of inactive double hexamer encircling DNA in head-to-head orie

Ref: Bell & Labib, Genes & Dev 2016, Pre-RC Assembly. Alberts 7th ed., Chapter 5, Replication Licensing.

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Cell Cycle Regulation

What is the role of Geminin in the cell cycle?

Eukaryotic replication origins must fire exactly once per cell cycle, a requirement enforced by strict licensing control. In G1, origin recognition complex recruits Cdc6 and Cdt1 to load MCM2-7 double hexamer helicases to form pre-replicative complexes. Upon S-phase entry, CDK and DDK activations fire origins and simultaneously trigger elimination of licensing factors to prevent re-assembly. Geminin provides a crucial additional layer independent of phosphorylation. Synthesized from S phase onward and stable through G2 and early mitosis, geminin directly binds coiled-coil domain of Cdt1 with h

Ref: McGarry & Kirschner, Geminin prevents DNA rereplication, Cell 1998; Alberts et al., Molecular Biology of the Cell, Chapter 5, Origin Licensing.

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