Influence of double-strand-break repair pathways on radiosensitivity throughout the cell cycle in CHO cells
Influence of double-strand-break repair pathways on radiosensitivity throughout the cell cycle in CHO cells
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DOI：
10.1016/j.dnarep.2005.03.005
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发表时间：
2005-07-12
期刊：
影响因子：
3.8
通讯作者：
Thompson, LH
中科院分区：
文献类型：
--
作者：
Hinz, JM;Yamada, NA;Thompson, LH
电离辐射（IR）引起的DNA双链断裂（DSB）是细胞杀伤的主要决定因素。为了确定DNA修复途径对IR敏感性中已确立的细胞周期变化的贡献，我们比较了野生型CHO细胞与非同源末端连接（NHEJ）缺陷突变系的放射敏感性。同源重组修复（HRR）和范可尼贫血途径。用杀死类似于每个异步群体的90%的IR剂量照射细胞。通过离心淘析分离成同步级分，并测定存活（集落形成）。野生型细胞在G1早期抗性最低，在S期抗性最高，然后随着细胞进入G2/M抗性下降。相比之下，HR缺陷细胞（xrcc 3突变）在G1早期最耐药，在S和G2/M期逐渐耐药。表明野生型细胞中的S期抗性需要HRR。NHEJ缺陷细胞（dna-pk（cs）突变）在G1早期非常敏感。S期抗性最强，G2/M期抗性稍弱。Fancg突变细胞具有几乎正常的IR敏感性和正常的细胞周期依赖性。这表明Fancg对存活有适度的贡献，并且以独立于细胞周期位置的方式。由爱思唯尔公司出版
Unrepaired DNA double-strand breaks (DSBs) produced by ionizing radiation (IR) are a major determinant of cell killing. To determine the contribution of DNA repair pathways to the well-established cell cycle variation in IR sensitivity, we compared the radiosensitivity of wild-type CHO cells to mutant lines defective in nonhomologous end joining (NHEJ). homologous recombination repair (HRR), and the Fanconi anemia pathway. Cells were irradiated with IR doses that killed similar to 90% of each asynchronous population. separated into synchronous fractions by centrifugal elutriation, and assayed for survival (colony formation). Wild-type cells had lowest resistance in early G 1 and highest resistance in S phase, followed by declining resistance as cells move into G2/M. In contrast, HR-defective cells (xrcc3 mutation) were most resistant in early G1 and became progressively less resistant in S and G2/M. indicating that the S-phase resistance in wild-type cells requires HRR. Cells defective in NHEJ (dna-pk(cs) mutation) were exquisitely sensitive in early G1. most resistant in S phase, and then somewhat less resistant in G2/M. Fancg mutant cells had almost normal IR sensitivity and normal cell cycle dependence. suggesting that Fancg contributes modestly to survival and in a manner that is independent of cell cycle position. Published by Elsevier B.V.