DNA POLYMERASE-DELTA FROM EMBRYOS OF DROSOPHILA-MELANOGASTER

We have purified a DNA polymerase activity from 0- to 2-hr embryos of Drosophila melanogaster to near homogeneity. The purified enzyme consi sts of a single 120-kDa polypeptide, which contains polymerase and 3'- ->5' exonuclease activities. Exonuclease activity is inhibited by deox ynucleoside triphosphates, suggesting that the polymerase and exonucle ase activities are coupled. The polymerase is more active with poly(dA -dT) than with activated DNA or poly(dA)/oligo(dT) as template. It sho ws a low degree of processivity with poly(dA)/oligo(dT). The polymeras e is sensitive to aphidicolin and carbonyldiphosphonate but resistant to N2-[p-(n-butyl)phenyl]-2-deoxyguanosine triphosphate, 2-[p-(n-butyl )anilino]-2-deoxyadenosine triphosphate, and dideoxythymidine triphosp hate. The 120-kDa polypeptide can be distinguished from the large subu nit of Drosophila DNA polymerase alpha on the basis of the peptides ge nerated by partial cleavage with N-chlorosuccinimide and by its failur e to react with a monoclonal antibody directed against the large subun it of DNA polymerase alpha. The DNA polymerase is inhibited by 200 mM NaCl and is unable to use poly(rA)/oligo(dT) as a template, thus diffe rentiating it from DNA polymerase gamma. On the basis of these propert ies, we propose that the-DNA polymerase that we have purified from 0- to 2-hr Drosophila melanogaster embryos is DNA polymerase delta.