Pol eta, also called Rad30A, is a translesion synthesis (TLS) polymerase. Translesion synthesis is a process that allows the bypass of a variety of DNA lesions. TLS polymerases lack proofreading activity and have low fidelity and low processivity. They use damaged DNA as templates and insert nucleotides opposite the lesions. Unlike other Y-family members, Pol eta can efficiently and accurately replicate DNA past UV-induced lesions. Its activity is initiated by two simultaneous interactions: the PIP box in pol eta interacting with PCNA, and the UBZ (ubiquitin-binding zinc finger) in pol eta interacting with monoubiquitin attached to PCNA. Pol eta is more efficient in copying damaged DNA than undamaged DNA and seems to recognize when a lesion has been passed, facilitating a lesion-dependent dissociation from the DNA.
Jiyao W et al.(2023). "The conserved domain database in 2023.",