Cell Lines Derived from a Medaka Radiation-Sensitive Mutant have Defects in DNA Double-Strand Break Responses
Cell Lines Derived from a Medaka Radiation-Sensitive Mutant have Defects in DNA Double-Strand Break Responses
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DOI：
10.1269/jrr.09107
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发表时间：
2010-03-01
影响因子：
2
通讯作者：
Mitani, Hiroshi
中科院分区：
文献类型：
--
作者：
Hidaka, Masayuki;Oda, Shoji;Mitani, Hiroshi
据报道，辐射敏感的Medaka突变体“ric1”在早期胚胎发育过程中存在伽马射线诱导的DNA双链断裂(DSB)修复缺陷。为了研究RIC1突变体对电离辐射的细胞反应，我们建立了突变的胚胎细胞系RIC1-E9、RIC1-E42、RIC1-E43。照射后1h内野生型细胞的双链断裂即可修复，而RIC1细胞的双链断裂在照射后2 h仍未修复，有细胞碎裂的野生型细胞可诱导细胞死亡，但只有少数RIC1细胞死亡，且未见细胞碎裂。虽然野生型和RIC1细胞在伽玛射线照射后立即表现出有丝分裂抑制，但野生型细胞的分裂恢复速度要慢得多(20h比12h)。在野生型和RIC1细胞中，伽马射线照射后均形成Ser139磷酸化的H_2AX(Gamma H_2AX)焦点，而RIC1细胞系中的H_2AX焦点消失得更快。这些结果表明，RIC1细胞中γ-H_2AX焦点的不稳定导致了DNA损伤反应的异常。由于RIC1培养的细胞表现出与RIC1胚胎相似的DNA修复缺陷，而RIC1细胞表现出缺陷的细胞死亡和细胞周期检查点，因此它们有助于在体外研究DNA损伤反应。
It was reported that the radiation-sensitive Medaka mutant "ric1" has a defect in the repair of DNA double-strand breaks (DSBs) induced by gamma-rays during early embryogenesis. To study the cellular response of a ric1 mutant to ionizing radiation (IR), we established the mutant embryonic cell lines RIC1-e9, RIC1-e42, RIC1-e43. Following exposure to gamma-irradiation, the DSBs in wild-type cells were repaired within 1 h, while those in RIC1 cells were not rejoined even after 2 h. Cell death was induced in the wild-type cells with cell fragmentation, but only a small proportion of the RIC1 cells underwent cell death, and without cell fragmentation. Although both wild-type and RIC1 cells showed mitotic inhibition immediately after gamma-irradiation, cell division was much slower to resume in the wild-type cells (20 h versus 12 h). In both wild-type and RIC1 cells, Ser139 phosphorylated H2AX (gamma H2AX) foci were formed after gamma-irradiation, however, the gamma H2AX foci disappeared more quickly in the RIC1 cell lines. These results suggest that the instability of gamma H2AX foci in RIC1 cells cause an aberration of the DNA damage response. As RIC1 cultured cells showed similar defective DNA repair as ric1 embryos and RIC1 cells revealed defective cell death and cell cycle checkpoint, they are useful For investigating DNA damage responses in vitro.