DNA polymerase lambda, also known as POLL, is a DNA polymerase involved in base excision repair (BER). POLL is a low-fidelity polymerase which plays a role in both spontaneous and DNA damage-induced mutagenesis. In addition, POLL may play a role in the mutagenic bypass of T-T dimers. Pol lambda possesses terminal transferase and 5’-deoxyribose-5-phosphate lyase activity. These activities have been found to be coordinated by PCNA and replication protein A.