Temporally distinct translesion synthesis pathways for ultraviolet light-induced photoproducts in the mammalian genome

► We describe a comprehensive set of assays to study genomic DNA damage tolerance. ► Ubiquitinated PCNA (PCNA-Ub), Polη, Rev1, and Rev3 are important for UV tolerance. ► PCNA-Ub is involved in bypass of CPD and (6-4)PP lesions, early after UV exposure. ► Rev1 plays PCNA-Ub-dependent and -independent roles in bypass of (6-4)PP. ► Late bypass of CPD requires PCNA-Ub, but not Polη.