A panel of murine hybridoma cell lines which produce antibodies against polypeptides present in human placental DNA polymerase δ preparations was developed. Eight of these antibodies were characterized by virtue of their ability to inhibit DNA polymerase δ activity and immunoblot the 170-kDa catalytic polypeptide. Six of these eight antibodies inhibit DNA polymerase δ but not DNA polymerase α, showing that the two proteins are distinct. However, the other two monoclonal antibodies inhibited both DNA polymerase δ and α activities, providing the first evidence that these two proteins have a structural relationship. In addition to antibodies against the catalytic polypeptide we also identified 11 antibodies which recognize 120-, 100-, 88-, 75-, 62-, 36-, and 22-kDa polypeptides in DNA polymerase δ preparations, suggesting that these proteins might be part of a replication complex. The antibody to the 36-kDa polypeptide was shown to be directed against proliferating cell nuclear antigen/cyclin. These antibodies should prove useful for studies aimed at distinguishing between DNA polymerases α and δ and for the investigation of the functional roles of DNA polymerase δ polypeptides.
ASJC Scopus subject areas
- Molecular Biology