"Damage-induced fork reversal in mammalian cells requires PCNA ubiquitination UBC13 and K63-linked polyubiquitin chains previously involved in error-free damage tolerance. Fork reversal in vivo also requires ZRANB3 translocase activity and its interaction with polyubiquitinated PCNA pinpointing ZRANB3 as a key effector of error-free DNA damage tolerance."xsd:string