Green M H, Lowe J E, James M R, Arlett C F
Kroc Found Ser. 1985;19:173-9.
Fibroblasts from ataxia-telangiectasia (AT) are hypersensitive to the lethal effects of ionizing radiation. Genomic DNA from normal human cells was transfected together with the selectable bacterial marker, gpt, on plasmid pSV2 into an SV40-transformed AT line, AT5BIVA. One radiation resistant clone (67) was recovered following repeated cycles of gamma-irradiation from a population of 90,000 clones. The normal level of radiation resistance has been maintained for at least 11 months in the absence of further selection by radiation. The resistant clone is not a contaminant as determined by isoenzyme analysis, carries one copy of the gpt gene, and its DNA synthesis is inhibited after radiation to an extent intermediate between that of AT and normal cells. It is not yet established whether clone 67 is a bona fide transformant or arose as a consequence of mutation of the parent AT line.
共济失调毛细血管扩张症（AT）患者的成纤维细胞对电离辐射的致死效应高度敏感。将来自正常人细胞的基因组DNA与质粒pSV2上的可选择细菌标记物gpt一起转染到SV40转化的AT细胞系AT5BIVA中。在90,000个克隆群体经过多次γ射线照射循环后，获得了一个抗辐射克隆（67）。在没有进一步辐射选择的情况下，抗辐射水平已维持至少11个月。通过同工酶分析确定该抗性克隆不是污染物，携带一份gpt基因拷贝，并且其DNA合成在辐射后受到抑制，抑制程度介于AT细胞和正常细胞之间。目前尚不确定克隆67是真正的转化体还是亲本AT细胞系突变的结果。
