MOLECULAR-CLONING OF THE CDNA FOR THE CATALYTIC SUBUNIT OF HUMAN DNA POLYMERASE-DELTA

The cDNA of human DNA polymerase-delta was cloned. The cDNA had a length of 3.5 kb and encoded a protein of 1107 amino acid residues with a calculated molecular mass of 124 kDa. Northern blot analysis showed that the cDNA hybridized to a mRNA of 3.4 kb. Monoclonal and polyclonal antibodies to the C-terminal 20 residues specifically immunoblotted the human pol-delta catalytic polypeptide. A multiple sequence alignment was constructed. This showed that human pol-delta is closely related to yeast pol-delta and the herpes virus DNA polymerases. The levels of pol-delta message were found to be induced concomitantly with DNA pol-delta activity and DNA synthesis in serum restimulated proliferating IMR90 cultured cells. The human pol-delta gene was localized to chromosome 19 by Southern blotting of EcoRI digested DNA from a panel of rodent/human cell hybrids.