Takahashi E I, Tsuji H, Shiomi T, Sato K, Tobari I
Mutat Res. 1982 Dec;106(2):225-36. doi: 10.1016/0027-5107(82)90104-x.
We have examined the chromosomal radiosensitivities of an ionizing-radiation-and MMS-sensitive mutant (M10), and a UV- and 4NQO-sensitive mutant (Q31), isolated from mouse lymphoma L5178Y cells, with regard to killing effects. In the first mitoses after 100 R gamma-irradiations, it was found that M10 cells were highly radiosensitive in terms of chromosomal aberrations accompanying longer mitotic delay (3 h); the frequencies of both chromatid-type and chromosome-type aberrations were, respectively, about 7 and 4 times higher than that of wild-type L5178Y cells. Furthermore, chromatid exchanges, particularly triradials, isochromatid breaks with sister union, and chromatid gaps and breaks were markedly enhanced at G1 phase of M10 cells. In contrast, the chromosomal radiosensitivity of Q31 cells after 100 R irradiation was similar to that of L5178Y cells. On the other hand, spontaneous aberration frequencies (overall breaks per cell) of M10 and Q31 cells were, respectively, 5.1 and 2.2 times higher than that of wild-type L5178Y cells. The chromosomal hypersensitivity to gamma-rays in M10 cells is discussed in the light of knowledge obtained from ataxia telangiectasia cells.
我们研究了从小鼠淋巴瘤L5178Y细胞中分离出的对电离辐射和甲磺酸甲酯敏感的突变体（M10）以及对紫外线和4-硝基喹啉-1-氧化物敏感的突变体（Q31）在杀伤效应方面的染色体放射敏感性。在100伦琴γ射线照射后的首次有丝分裂中，发现M10细胞在伴随较长有丝分裂延迟（3小时）的染色体畸变方面具有高度放射敏感性；染色单体型和染色体型畸变的频率分别比野生型L5178Y细胞高约7倍和4倍。此外，在M10细胞的G1期，染色单体交换，特别是三射体、姐妹染色单体联合的等染色单体断裂以及染色单体间隙和断裂明显增加。相比之下，100伦琴照射后Q31细胞的染色体放射敏感性与L5178Y细胞相似。另一方面，M10和Q31细胞的自发畸变频率（每个细胞的总断裂数）分别比野生型L5178Y细胞高5.1倍和2.2倍。根据从共济失调毛细血管扩张症细胞中获得的知识，讨论了M10细胞对γ射线的染色体超敏感性。
