The objective of the proposed research project is to define possible controls for DNA biosynthesis during normal and neoplastic growth. 1) A multi-enzyme complex for DNA biosynthesis in normal proliferating and neoplastic cells will be further characterized and its possible in vivo function studied. 2) DNA polymerases in normal and neoplastic cells will continue to be studied as a prelude to determining their physiological functions. 3) The DNases in nuclei of normal and neoplastic cells will be characterized and their relationship to DNA replication and/or repair investigated. 4) In vitro DNA synthesis with isolated nuclei from normal and neoplastic cells will be investigated for the role of cell integrity in the control.