Shiomi T, Hieda-Shiomi N, Sato K
Mutat Res. 1983 Mar;108(1-3):395-404. doi: 10.1016/0027-5107(83)90135-5.
The X-ray-sensitive mutant M10 and the UV-sensitive mutant Q31 of mouse lymphoma L5178Y cells are both sensitive to killing by 4-nitroquinoline-1-oxide (4NQO). Since cell hybridization experiments showed that the 4NQO sensitivities in M10 and Q31 cells behaved as codominant traits (Shiomi et al., 1982c), it is not possible to determine by complementation test whether the M10 and the Q31 mutations responsible for 4NQO sensitivities are allelic. We have obviated this difficulty by selecting double mutants that are sensitive to both X-rays and UV. From X-ray-sensitive M10 cells, two UV-sensitive mutants (XU 1 and XU 2) were isolated by a cell-suspension spotting method. XU 1 and XU 2 were found to belong to the same complementation group as Q31 (group I). Double mutants XU 1 and XU 2 were 30-37-fold more sensitive to 4NQO than parental L5178Y cells, whereas the single mutants M10 and Q31 were only 6-8-fold more sensitive to 4NQO than L5178Y cells in terms of D10 values (dose required to reduce survival to 10%). These results show that the M10-Q31-double mutations enhance 4NQO sensitivity synergistically, indicating that the M10 and the Q31 mutations relevant to 4NQO sensitivities are non-allelic. The implications of this finding are discussed.
小鼠淋巴瘤L5178Y细胞的X射线敏感突变体M10和紫外线敏感突变体Q31对4-硝基喹啉-1-氧化物（4NQO）杀伤均敏感。由于细胞杂交实验表明M10和Q31细胞中的4NQO敏感性表现为共显性性状（Shiomi等人，1982c），因此无法通过互补试验确定导致4NQO敏感性的M10和Q31突变是否为等位基因。我们通过选择对X射线和紫外线均敏感的双突变体克服了这一困难。从X射线敏感的M10细胞中，通过细胞悬液斑点法分离出两个紫外线敏感突变体（XU 1和XU 2）。发现XU 1和XU 2与Q31属于同一互补群（I组）。就D10值（将存活率降低至10%所需的剂量）而言，双突变体XU 1和XU 2对4NQO的敏感性比亲本L5178Y细胞高30 - 37倍，而单突变体M10和Q31对4NQO的敏感性仅比L5178Y细胞高6 - 8倍。这些结果表明，M10 - Q31双突变协同增强了4NQO敏感性，表明与4NQO敏感性相关的M10和Q31突变是非等位基因。本文讨论了这一发现的意义。
