Transfer of Thymidine Kinase to Cells Lacking This Enzyme by Infection with Ultraviolet Irradiated Herpes Simplex Virus

Transformation of Cultured Mammalian Cells by Viable Herpes Simplex Virus Subtypes 1 and 2

“…Cells transformed in culture by HSV might provide a valuable system to explore the oncogenic potential of this virus. Biochemical transformation of thymidine-kinase-deficient (TK-) mouse cells to the thymidine-kinase-positive phenotype has in fact been achieved using ultra-violet inactivated HSV (3). The molecular basis of the mode of selection of transformants and of the acquisition of new kinase function has yet to be rigorously established, although the available evidence is consistent with the conclusion that the cells stably inherit the capacity to synthesize thymidine kinase (TK) that is specific for HSV.…”

Nucleotide sequence of the thymidine kinase gene of herpes simplex virus type 1.

“…Viral TK also can be expressed in TK-cells which have been "biochemically transformed" to a TKV phenotype by infection with UV-inactivated virus (6,7) or viral DNA fragments (8). The TK gene is heritably and stably incorporated into the genome of the cell and is expressed in the apparent absence of the immediate-early viral gene products.…”

Cloning of the active thymidine kinase gene of herpes simplex virus type 1 in Escherichia coli K-12.

“…Normal mouse L cells and TK-mouse LM cells (clone iD) were grown in Leibovitz L15 medium containing 5% calf serum (kindly provided by J. C. Guillon and G. Buttin, respectively). TK+ cells were selected in the same medium supplemented with thymidine, adenosine, guanosine, glycine, and aminopterin (Sigma) (HAT medium) as described (1 Restriction fragments were recovered from agarose gel slices either by electrophoresis or by freezing and thawing (8,9) and further purified as follows: to 1 vol of DNA solution, 1 vol of 2.5 M potassium phosphate buffer (pH 7.6) and 1 vol of 2-methoxyethanol (10) were added. After gentle mixing, the two phases were allowed to separate for 30 min at 4°C and were centrifuged for 30 min at 6000 X g at 4°C.…”