Bacchetti S, Graham F L
IARC Sci Publ (1971). 1978(24 Pt 1):495-9.
Human TK- cells carrying the HSV-2 TK gene express a TK activity of viral origin and maintain the TK+ phenotype when grown in HAT medium. Under non-selective or counterselective conditions, however, reversion to a TK- phenotype occurs with a significant frequency characteristic of each transformed line. The TK- phenotype appears to be stable since no instances of TK- to TK+ reversion have been observed.
携带单纯疱疹病毒2型胸苷激酶（HSV - 2 TK）基因的人胸苷激酶阴性（TK-）细胞表达病毒来源的胸苷激酶活性，并在次黄嘌呤-氨基蝶呤-胸腺嘧啶核苷（HAT）培养基中培养时维持胸苷激酶阳性（TK+）表型。然而，在非选择性或反选择条件下，每个转化细胞系都有显著频率的细胞回复为TK-表型。由于未观察到TK-向TK+回复的情况，TK-表型似乎是稳定的。
