Siciliano M J, White B F, Humphrey R M
Mutat Res. 1983 Jan;107(1):167-76. doi: 10.1016/0027-5107(83)90086-6.
Chinese hamster ovary (CHO) cells were subjected to ultraviolet radiation (UV) at doses resulting in 100% (no irradiation), 50-30%, 20-10% and approximately 1% survival. 2 divisions after UV exposure surviving cells were cloned and clones expanded for electrophoretic analysis of the products of approximately 40 enzyme loci. 4 different classes of variants (electrophoretic shifts, nulls, enzyme re-expression and enzyme modification) were detected in 29 of 1329 clones analyzed and proven mutants by subclone analysis. The frequency of mutants in the irradiated groups (28/38391 loci screened or 7.3 X 10(-4) was significantly higher than controls. The frequency of shift mutants at 10-20% survival was higher than shifts at 30-50% survival and was significantly higher than shifts at approximately 1% survival. The frequency of nulls increased with dose. 12 of the 28 mutants obtained in the irradiated groups were at only 3 of the mean 41 loci screened/clone. These results indicated that shift mutants could be detected more efficiently than nulls at lower dose and that loci varied widely with respect to their susceptibility to UV mutagenesis. Multiple null mutants at 2 loci, isocitrate dehydrogenase 2 and hexokinase 2, indicated they may be hemizygous in CHO cells.
将中国仓鼠卵巢（CHO）细胞暴露于紫外线辐射（UV）下，剂量分别导致100%（未照射）、50 - 30%、20 - 10%和大约1%的存活率。紫外线照射后存活细胞经过2次分裂进行克隆，并扩大克隆群体用于对大约40个酶位点的产物进行电泳分析。在分析的1329个克隆中的29个中检测到4种不同类型的变体（电泳迁移、无效突变、酶重新表达和酶修饰），并通过亚克隆分析证实为突变体。照射组中的突变体频率（在38391个筛选位点中有28个，即7.3×10⁻⁴）显著高于对照组。存活率为10 - 20%时的迁移突变体频率高于存活率为30 - 50%时的迁移突变体频率，且显著高于存活率约为1%时的迁移突变体频率。无效突变体的频率随剂量增加。照射组获得的28个突变体中有12个仅位于平均每个克隆筛选的41个位点中的3个位点上。这些结果表明，在较低剂量下检测迁移突变体比检测无效突变体更有效，并且不同位点对紫外线诱变的敏感性差异很大。在异柠檬酸脱氢酶2和己糖激酶2这两个位点出现多个无效突变体，表明它们在CHO细胞中可能是半合子状态。
