The complexity of DNA double strand break is a crucial factor for activating ATR signaling pathway for G2/M checkpoint regulation regardless of ATM function
The complexity of DNA double strand break is a crucial factor for activating ATR signaling pathway for G2/M checkpoint regulation regardless of ATM function
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DOI：
10.1016/j.dnarep.2014.11.004
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发表时间：
2015-01-01
期刊：
影响因子：
3.8
通讯作者：
Yu, Dong
中科院分区：
文献类型：
--
作者：
Xue, Lian;Furusawa, Yoshiya;Yu, Dong
电离辐射(IR)后DNA双链断裂(DSB)修复途径的选择是目前研究的热点，但仍不十分清楚。我们最近的论文指出，DSB的复杂性是提高DNA末端切除的关键因素。已被公认的是，切除产生的RPA包被的单链DNA是ATR激活的信号结构。因此，利用高线性能量转移(LET)辐射来有效地产生复杂的DSB，我们研究了DSB的复杂性如何影响ATR通路在G2/M检查点调节中的功能。用X射线或重离子粒子照射有或无ATM的人皮肤成纤维细胞，用双参数流式细胞术通过检测组蛋白H3阳性的细胞来定量评价辐射后早期有丝分裂的进入。在ATM缺陷细胞中，ATR途径起着关键作用，并以剂量和LET依赖的方式调节早期的G2/M期停滞，即使在0.2GY的重离子辐射下也是如此，这表明在IR暴露后，ATR通路可以以ATM不依赖的方式迅速激活并发挥作用，但DSB的复杂性依赖于ATR途径的功能。此外，ATR通路也在ATM熟练的细胞中更有效地发挥作用，在粒子辐射暴露的早期阻断G2向M的转变。因此，与ATM抑制剂相比，ATR抑制剂对重离子照射后的存活率具有更有效的放射增敏作用。综上所述，我们的结果表明，DSB的复杂性是激活ATR通路以调节G2/M检查点的关键因素，而ATM依赖的末端切除并不是激活所必需的。(C)2014爱思唯尔B.V.保留所有权利。
DNA double strand break (DSB) repair pathway choice following ionizing radiation (IR) is currently an appealing research topic, which is still largely unclear. Our recent paper indicated that the complexity of DSBs is a critical factor that enhances DNA end resection. It has been well accepted that the RPA-coated single strand DNA produced by resection is a signaling structure for ATR activation. Therefore, taking advantage of high linear energy transfer (LET) radiation to effectively produce complex DSBs, we investigated how the complexity of DSB influences the function of ATR pathway on the G2/M checkpoint regulation. Human skin fibroblast cells with or without ATM were irradiated with X rays or heavy ion particles, and dual-parameter flow cytometry was used to quantitatively assess the mitotic entry at early period post radiation by detecting the cells positive for phosphor histone H3. In ATM-deficient cells, ATR pathway played a pivotal role and functioned in a dose- and LET-dependent way to regulate the early G2/M arrest even as low as 0.2 Gy for heavy ion radiation, which indicated that ATR pathway could be rapidly activated and functioned in an ATM-independent, but DSB complexity-dependent manner following exposure to IR. Furthermore, ATR pathway also functioned more efficiently in ATM-proficient cells to block G2 to M transition at early period of particle radiation exposure. Accordingly, in contrast to ATM inhibitor, ATR inhibitor had a more effective radiosensitizing effect on survival fraction following heavy ion beams as compared with X ray radiation. Taken together, our results reveal that the complexity of DSBs is a crucial factor for the activation of ATR pathway for G2/M checkpoint regulation, and ATM-dependent end resection is not essential for the activation. (C) 2014 Elsevier B.V. All rights reserved.