Abstract
A DNA-synthesizing system in vitro, using nuclei prepared by treatment of human lymphocytes with the detergent Brij 58, was developed. Nuclei from cultured lymphocytes synthesized DNA for as long as 5 hr, and required ATP, deoxynucleoside triphosphates, magnesium, and a calcium chelator. In nuclei from a partially synchronized line of cultured lymphocytes carrying several hundred copies of the Epstein-Barr viral genome, synthesis in vitro was predominately viral in early S phase and cellular in late S phase. These and other data suggested that the DNA synthesis observed in vitro was predominately replicative.