Abstract: Mammalian DNA polymerase δ (Pol δ) is a tightly associated heterotetrameric complex, consisting of the p125, p50, p68 and p12 subunits, which plays a crucial role in DNA replication and various DNA repair processes. Pol δ possesses both polymerase and 3′-5′ exonuclease activities. Since the isolation of Pol δ from rabbit bone marrow cytoplasm for the first time in 1976, the Pol δ enzyme complex has been isolated and purified from calf thymus and various mammalian cells, but the purification process is extremely cumbersome and the yield is low. It is difficult to obtain a biologically active Pol δ multi-subunit complex, which seriously hinders our study for the enzymatic properties of mammalian Pol δ. With the development of the insect-baculovirus expression system, the recombinant eukaryotic Pol δ multi-subunit complex was recently prepared by this system, which greatly facilitated the studies of the enzymatic and biochemical characteristics of the enzyme. This article briefly reviews the research progress of the isolation and purification of mammalian DNA polymerase δ from natural sources and the preparation of recombinant Pol δ multi-subunit complex by baculovirus-based expression system.

Key words: DNA polymerase δ, separation and purification, multi-subunit complex