Question

Explain the central role played by CdK (cell cycle-dependent kinases) in the transition from G1 to S and preRC to preIC at DNA origins of replication. Use the diagram below for help

RC ORC Cyclin A/B+ Cdk APC Licensed DNA Rb DNA replication MCM ORC Rb S G1 D cyclins Cdk4/6 Cyclin A Cdk2 Cyclin E+Cdk2 ORC DNA licensing inactivation Skp2 CUL4 → Cok

Answer 1

cdk phosphorylates the MCM ,ORC and cdc6 that dispalces cdc6 and cdt1 from the preRC and further recruitment of replicative DNA polymerase α and its primase for DNA replication form the preIC where DNA replication begins.hereafter cell enter in S-phase.