Molecular Pharmacology, Vol 6, 281-291, Copyright © 1970 by the American Society for Pharmacology and Experimental Therapeutics

Fluorinated Pyrimidines

XXXVIII. The Incorporation of 5-Trifluoromethyl-2'-deoxyuridine into the Deoxyribonucleic Acid of Vaccinia Virus

¹ McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, Wisconsin 53706

A comparison has been made of the properties of purified vaccina virions replicated in HeLa cells in the presence of thymidine or the powerfully antiviral 5-trifluoromethyl-2'-deoxyuridine (F₃TdR). The replacement of thymidine by the analogue in the DNA of the virions amounted to 1.4-9.8%, and such virions were noninfective. Sucrose density gradient centrifugation of the DNA isolated from purified virions revealed that the normal virions had a sedimentation coefficient to 70, whereas the analogue-containing DNA sedimented with S-values of 52 and 39. The presence of F₃TdR in the medium did not affect the process of uncoating of the infecting virions, but recoating of the viral DNA occurred to only 50% of normal. The morphology of vaccinia virions containing F₃TdR in their DNA was considerably different from normal.