The synthesis of vaccinia virus-induced thymidine kinase is normally arrested several hours after infection. In thymidine kinase-deficient LM cells infected with IHD strain of vaccinia virus, arrest occurs whether or not viral DNA synthesis is inhibited. With virus inactivated by UV irradiation, enzyme synthesis takes place, but arrest is abolished. It is suggested that an early viral genetic f...

Thymidine may act as an inducer of thymidine kinase activity in cells of higher plants. The general response is demonstrable in a randomly developing cell population such as is found in germinating wheat embryos. If a synchronously developing cell population is studied, however, potentially inducible cells are found to be susceptible to the inductive effect of thymidine only during about 10 per...

In estrogen-dependent rat adrenocortical carcinomas, thymidine kinase activity decreased during tumor regression following removal of estrogen from the host. The change in the kinase activity could be prevented by estrogen administration but not by the administration of growth hormone or adrenocorticotropic hormone. The alterations in kinase activity were not due to changes in the activity of c...

Computer techniques were used to locate related segments of amino acid sequences in the thymidine kinases of vaccinia virus and of herpes simplex virus type 1 and in porcine adenylate kinase. As determined by a procedure that evaluates triply aligned sequences, the probability that the similarities among the segments described here arose by chance was no greater than 0.001. Because the sequence...

Accumulation of thymidine kinase activity in vaccinia virus-infected cells was severely inhibited by zinc ions if the drug was added within 1 h postinfection. If added later, zinc ions had no effect on the enzyme synthesis. A fraction of RNA which is normally synthesized in infected cells, was missing from a proper part of the gradient if the cells were treated with zinc ions within 1 h postinf...