Radiation induced DNA DSBs: Contribution from stalled replication forks?
Radiation induced DNA DSBs: Contribution from stalled replication forks?
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DOI：
10.1016/j.dnarep.2010.06.002
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发表时间：
2010-08-05
期刊：
影响因子：
3.8
通讯作者：
O'Neill, Peter
中科院分区：
文献类型：
--
作者：
Harper, Jane V.;Anderson, Jennifer A.;O'Neill, Peter
当细胞暴露于辐射时，严重的损伤被引入DNA中，包括双链断裂（DSB）、单链断裂（SSB）、碱基修饰和成簇的损伤位点（电离辐射诱导的DNA损伤的一个具体特征）。辐射诱导的DNA损伤有可能引发最终导致突变和癌症发作的事件，因此了解细胞对DNA损伤的反应特别重要。使用γ H2 AX作为DSB形成的标志物和RAD 51作为同源重组（HR）的标志物，其在坦率的DSB或由停滞的复制叉产生的DSB的处理中被招募，我们已经研究了SSBs和非DSB DNA损伤对在细胞周期期间通过电离辐射在哺乳动物细胞中诱导DSB的贡献。V79-4细胞和人HF 19成纤维细胞已经用0-20戈伊的γ辐射照射，或者为了比较，用低浓度的过氧化氢处理，已知过氧化氢诱导SSB而不是DSB。通过聚（ADP核糖）聚合酶（PARP）抑制剂抑制氧化DNA损伤的修复导致辐射诱导的γ H2 AX和RAD 51焦点的增加，我们认为这是由于这些损伤与复制叉碰撞形成复制诱导的DSB。已证实，用过氧化氢处理在G（1）期细胞中不诱导DSB，但处理确实导致DSB诱导，特别是在S期细胞中。因此，我们认为辐射诱导的SSB和非DSB DNA损伤有助于复制诱导的DSB的形成，检测为RAD 51灶。(C)2010 Elsevier B. V.保留所有权利。
When cells are exposed to radiation serious lesions are introduced into the DNA including double strand breaks (DSBs), single strand breaks (SSBs), base modifications and clustered damage sites (a specific feature of ionizing radiation induced DNA damage). Radiation induced DNA damage has the potential to initiate events that can lead ultimately to mutations and the onset of cancer and therefore understanding the cellular responses to DNA lesions is of particular importance. Using gamma H2AX as a marker for DSB formation and RAD51 as a marker of homologous recombination (HR) which is recruited in the processing of frank DSBs or DSBs arising from stalled replication forks, we have investigated the contribution of SSBs and non-DSB DNA damage to the induction of DSBs in mammalian cells by ionizing radiation during the cell cycle. V79-4 cells and human HF19 fibroblast cells have been either irradiated with 0-20 Gy of gamma radiation or, for comparison, treated with a low concentration of hydrogen peroxide, which is known to induce SSBs but not DSBs. Inhibition of the repair of oxidative DNA lesions by poly(ADP ribose) polymerase (PARP) inhibitor leads to an increase in radiation induced gamma H2AX and RAD51 foci which we propose is due to these lesions colliding with replication forks forming replication induced DSBs. It was confirmed that DSBs are not induced in G(1) phase cells by treatment with hydrogen peroxide but treatment does lead to DSB induction, specifically in S phase cells. We therefore suggest that radiation induced SSBs and non-DSB DNA damage contribute to the formation of replication induced DSBs, detected as RAD51 foci. (C) 2010 Elsevier B.V. All rights reserved.