Nakano M M, Sekiguchi T, Yamada M A
Somatic Cell Genet. 1978 Mar;4(2):169-78. doi: 10.1007/BF01538982.
We have isolated a mutant clone from mouse FM3A cells with temperature-sensitive defects both in cytokinesis and in thymidine kinase enzyme activity. The clone, designated tsCl.B59, was isolated after mutagenesis at 33 degrees C followed by exposure to cytosine arabinoside at 39 degrees C. It was derived from a thymidine kinase deficient, 5-bromodeoxyuridine-resistant clone (S-BUCl.42) which was originally derived from wild-type clone H-5 of FM3A cells. The temperature-sensitive mutant clone grows normally at 33 degrees C, but not at 39 degrees C, where it exhibits an increased frequency of multinucleate cells due to defective cytokinesis. Unlike the parental S-BUCl.42 cells, which have negligible thymidine kinase activity and are unable to incorporate 3H-thymidine, the mutant in corporates substantial amounts of 3H-thymidine at 33 degrees C, although its thymidine kinase activity remains lower than that of wild-type H-5 cells. When cultures of tsCl.B59 cells are transferred to 39 degrees C, incorporation of 3H-thymidine decreases markedly. The decrease has been shown to be due to thermolability of the thymidine kinase in tsCl.B59 cells.
我们从小鼠FM3A细胞中分离出一个突变克隆，该克隆在胞质分裂和胸苷激酶酶活性方面均存在温度敏感缺陷。这个名为tsCl.B59的克隆是在33℃诱变后，于39℃暴露于阿糖胞苷后分离得到的。它源自一个胸苷激酶缺陷、对5-溴脱氧尿苷耐药的克隆（S-BUCl.42），而S-BUCl.42最初源自FM3A细胞的野生型克隆H-5。这个温度敏感突变克隆在33℃时正常生长，但在39℃时不能生长，在39℃时由于胞质分裂缺陷，多核细胞的频率增加。与亲本S-BUCl.42细胞不同，S-BUCl.42细胞的胸苷激酶活性可忽略不计且无法掺入3H-胸苷，而该突变体在33℃时能掺入大量3H-胸苷，尽管其胸苷激酶活性仍低于野生型H-5细胞。当tsCl.B59细胞培养物转移到39℃时，3H-胸苷的掺入量显著下降。已证明这种下降是由于tsCl.B59细胞中胸苷激酶的热不稳定性所致。
