Replication origin under-licensing extends S phase and leads to mitotic entry before S-phase completion. At mitotic entry, M-CDKs phosphorylate DNA Pol, leading to its eviction from chromatin, which activates the DNA Damage Checkpoint. This provides time to complete DNA synthesis by MiDAS at the expense of genome stability. Pol1 and Pol1-Cdk13A interactomes were analyzed during S phase and mitosis in a context of an extended S phase.