Positional Stability of Damaged Chromatin Domains along Radiation Tracks in Mammalian Cells
Positional Stability of Damaged Chromatin Domains along Radiation Tracks in Mammalian Cells
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DOI：
10.1667/rr1520.1
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发表时间：
2009-04-01
影响因子：
3.4
通讯作者：
Taucher-Scholz, G.
中科院分区：
文献类型：
--
作者：
Jakob, B.;Splinter, J.;Taucher-Scholz, G.
带电粒子辐照细胞核导致沿粒子轨迹的DNA损伤在空间上的产生，从而促进与损伤处理相关的辐射诱导蛋白质焦点的动力学研究。在这里，我们使用肉眼观察和免疫检测后轨迹形态的计算分析来描述伽马-H_2AX焦点和修复相关蛋白53BP1和RPA的形成模式。我们利用低能碳离子或铀离子对细胞单层进行小角度照射，研究了损伤密度对γ-H_2AX形成的影响以及受损染色质位置的迁移率。我们显示了在人成纤维细胞和HeLa细胞中，在200keV/mum到14300 keV/mum的LET范围内，伽马-H_2AX焦点的离散形成和修复相关蛋白沿着离子轨迹的招募。标记的DSB表现出与LET无关的有限的移动性。人成纤维细胞的适度流动性表明，修复过程中受损的染色质结构域定位相对稳定，而HeLa细胞则显示出部分细胞中条纹图案的显著变化，这表明在DSB的局部处理中有更大的流动性。我们的数据表明，单个或多个DSB的存在与受损染色质移动潜力的改变无关。我们推断，哺乳动物细胞中高LET辐射诱导的双链断裂的修复与病变运动活性的增加并不耦合，从而增加了易位的可能性。(C)2009年，由辐射研究学会提供
Irradiation of cell nuclei with charged particles leads to the spatially defined production of DNA damage along the particle trajectories, thus facilitating studies on the dynamics of radiation-induced protein foci associated with lesion processing. Here we used visual inspection and computational analysis of the track morphology after immunodetection to describe the patterns of formation of gamma-H2AX foci and the repair-related proteins 53BP1 and RPA. We addressed the influence of lesion density on gamma-H2AX formation and the mobility of damaged chromatin sites by using low-angle irradiation of cell monolayers with low-energy carbon or uranium ions. We show the discrete formation of gamma-H2AX foci and the recruitment of repair-related proteins along ion trajectories over an LET range from 200 to 14300 keV/mu m in human fibroblasts and in HeLa cells. The marked DSBs exhibited a limited mobility that was independent of the LET. The moderate extent of mobility in human fibroblasts pointed to a relatively stable positioning of the damaged chromatin domains during repair, in contrast to HeLa cells, which showed significant changes in the streak patterns in a fraction of cells, suggesting greater mobility in the local processing of DSBs. Our data indicate that the presence of single or multiple DSBs is not associated with an altered potential for movement of damaged chromatin. We infer that the repair of high-LET radiation-induced DSBs in mammalian cells is not coupled to an increased motional activity of lesions enhancing the probability of translocations. (C) 2009 by Radiation Research Society