Establishment of mutant FM3A murine mammary carcinoma cell strains transformed with the herpes simplex virus type 1 thymidine kinase gene.

To establish cell systems appropriate for investigating the mode of action of anti-herpetic nucleoside analogs, mutants were constructed from murine FM3A mammary carcinoma cells, which were deficient in both thymidine kinase (EC 2.7.1.21) and thymidylate synthase (EC 2.1.1.45), but were transformed with a recombinant plasmid DNA containing the herpes simplex virus type 1 thymidine kinase gene. The transformed cells expressed viral thymidine kinase activity and showed unusually high sensitivity to the cytostatic action of the antiherpetic agent (E)-5-(2-iodovinyl)-2'-deoxyuridine, which was only weakly inhibitory to the growth of the parent cells.