ISOLATION AND SEQUENCE DETERMINATION OF THE CDNA-ENCODING DNA-POLYMERASE-DELTA FROM DROSOPHILA-MELANOGASTER

The cDNA encoding the catalytic subunit of Drosophila melanogaster (Dm ) DNA polymerase delta (Pol delta) was isolated by a combination of PC R amplification and cDNA library screening. The cDNA is 3457 nucleotid es in length and contains an open reading frame (ORF) that encodes a p rotein of 1092 amino acids (124 799 Da). The ORF contains the sequence that was determined for a peptide from the purified catalytic subunit of Dm Pol delta. Polyclonal antibodies raised against Dm Pol delta sp ecifically recognize a protein of the expected size when the cDNA is e xpressed in either Escherichia coli or insect cells. Comparison of the deduced aa sequence with other Pol delta sequences demonstrates that Pol delta is one of the most highly conserved of the DNA polymerases.