REPLICATION OF A DEOXYRIBONUCLEIC ACID VIRUS IN THYMINE-DEFICIENT MAMMALIAN CELLS.

Gentry, Glenn A. (University of Mississippi School of Medicine, Jackson), Lucy A. Lawson, and Charles C. Randall. Replication of a deoxyribonucleic acid virus in thymine-deficient mammalian cells. J. Bacteriol. 88:1324-1328. 1964.-Equine abortion virus (EAV), a deoxyribonucleic acid (DNA) virus, causes the degradation of host cell DNA to acid-soluble components in the L-M cell. It was hypothesized that inhibitors of DNA synthesis such as 5-fluorodeoxyuridine (FUdR) and amethopterin, which act by causing a deficiency in thymidine (TdR) nucleotides, would not block virus replication because the breakdown of the host cell DNA would supply sufficient TdR nucleotides for synthesis of viral DNA. The drugs were added 24 hr prior to the virus, amethopterin at 10(-6)m with adenosine included as a purine source, or FUdR at 10(-5)m. In either case, control experiments indicated that the thymineless state was achieved in the host cells. When EAV was added, neither FUdR nor amethopterin had any effect on the production of infectious virus, as determined by plaque assay, thus supporting the hypothesis.