Abstract
Increased DNA polymerase (E.C. 2.7.7.7[EC] ) activity after infection with vaccinia virus has been found in several different host cell systems (Magee, 1962; Green, Piña & Chagoya, 1964; Jungwirth & Joklik, 1965). Various lines of evidence indicate that this increase results from the formation of a new DNA polymerase (Jungwirth & Joklik, 1965; Magee & Miller; 1967; Berns, Silverman & Weissbach, 1969).
We report here that the enzyme produced in two different infected-cell systems has similar properties, and can in each case be distinguished from the DNA polymerase of the uninfected cells. This suggests that the genetic information for the post-infection DNA polymerase is encoded in the virus genome, rather than in a normally repressed portion of the host cell genome.
L cells were grown in suspension as described by Gold & Helleiner (1964). Primary explants of chick embryo fibroblasts were prepared by the method of Paul (1965).
* Present address: Department of Physiology and Biochemistry, University of Southampton, Southampton, England.