Using monodispersed cell suspensions, interferon preparations were shown to have both a lethal and a growth-depression effect in the same concentration range as that required for antiviral activity. In addition, synchronized cells treated with interferon respond by delaying their normal uptake of thymidine during S phase until after a period during which new protein is synthesized. Puromycin added during this period prevents both the synthesis of this protein and the subsequent synthesis of DNA.

SUMMARYPurified preparations of L cell virions (LCV) were found to: possess an associated DNA polymerase activity. This enzyme was active with poly(C), oligo(dG) and poly(Cm), oligo(dG) and was able to transcribe poly(A), oligo(dT). Endogenous DNA synthesis was also demonstrable in disrupted virion preparations but this reaction was enhanced, rather than inhibited, by RNase pre-treatment. The effects of variations in a number of the assay parameters on these activities were examined in an attempt to determine the class of DNA polymerase involved.