- Cdk-interacting protein 1 directly binds with proliferating cell nuclear antigen and inhibits DNA replication catalyzed by the DNA polymerase delta holoenzyme. Flores-Rozas, H., Kelman, Z., Dean, F.B., Pan, Z.Q., Harper, J.W., Elledge, S.J., O'Donnell, M., Hurwitz, J. Proc. Natl. Acad. Sci. U.S.A. (1994)