Error-prone nonhomologous end joining repair operates in human pluripotent stem cells during late G2.
Error-prone nonhomologous end joining repair operates in human pluripotent stem cells during late G2.
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DOI：
10.18632/aging.100336
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发表时间：
2011-06
期刊：
影响因子：
--
通讯作者：
Kiselev SL
中科院分区：
文献类型：
--
作者：
Bogomazova AN;Lagarkova MA;Tskhovrebova LV;Shutova MV;Kiselev SL
人类胚胎干细胞（hESC）的基因组稳定性是一个重要的问题，因为即使是微小的遗传改变也会对细胞的功能和安全性产生负面影响。DNA双链断裂（DSBs）的错误修复是染色体畸变形成的根本原因。采用G2放射敏感性试验分析了多能干细胞和体细胞的染色体畸变。辐照后2小时，hESCs的染色单体交换畸变率比其分化衍生物增加了许多倍，但辐射诱导的染色单体断裂频率相似。辐射诱导的染色单体交换率在hESCs和分化细胞中表现出二次剂量响应，揭示了交换形成的双命中机制，提示非同源末端连接（NHEJ）修复可能参与了它们的形成。NU7026对NHEJ关键成分DNA-PK的抑制作用导致辐射诱导的hESCs染色单体交换显著减少，但对体细胞没有影响。相比之下，NU7026处理在多能细胞和体细胞中增加了辐射诱导断裂的频率，其程度相似。因此，DNA-PK依赖的NHEJ在两种细胞类型的G2晚期有效地参与消除辐射诱导的染色单体断裂，DNA-PK活性导致高水平的错误重新连接，特别是在多能细胞中。
Genome stability of human embryonic stem cells (hESC) is an important issue because even minor genetic alterations can negatively impact cell functionality and safety. The incorrect repair of DNA double-stranded breaks (DSBs) is the ultimate cause of the formation of chromosomal aberrations. Using G2 radiosensitivity assay, we analyzed chromosomal aberrations in pluripotent stem cells and somatic cells. The chromatid exchange aberration rates in hESCs increased manifold 2 hours after irradiation as compared with their differentiated derivatives, but the frequency of radiation-induced chromatid breaks was similar. The rate of radiation-induced chromatid exchanges in hESCs and differentiated cells exhibited a quadratic dose response, revealing two-hit mechanism of exchange formation suggesting that a non-homologous end joining (NHEJ) repair may contribute to their formation. Inhibition of DNA-PK, a key NHEJ component, by NU7026 resulted in a significant decrease in radiation-induced chromatid exchanges in hESCs but not in somatic cells. In contrast, NU7026 treatment increased the frequency of radiation-induced breaks to a similar extent in pluripotent and somatic cells. Thus, DNA-PK dependent NHEJ efficiently participates in the elimination of radiation-induced chromatid breaks during the late G2 in both cell types and DNA-PK activity leads to a high level of misrejoining specifically in pluripotent cells.
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DOI：
10.1007/s11626-010-9282-6
发表时间：
2010-04-01
影响因子：
2.1
作者：
Lagarkova, Maria A.;Eremeev, Artem V.;Kiselev, Sergei L.
通讯作者：
Kiselev, Sergei L.
影响因子：
4.3
作者：
Chuykin, Ilya A.;Lianguzova, Maria S.;Pospelov, Valery A.
通讯作者：
Pospelov, Valery A.
影响因子：
4.3
作者：
Lagarkova, Maria A.;Shutova, Maria V.;Kiselev, Sergey L.
通讯作者：
Kiselev, Sergey L.
影响因子：
11.4
作者：
Essers, J;van Steeg, H;Kanaar, R
通讯作者：
Kanaar, R
影响因子：
14.8
作者：
Baudin, Bruno;Bruneel, Arnaud;Vaubourdolle, Michel
通讯作者：
Vaubourdolle, Michel