Angewandte Physik und Messtechnik LRT2, Universität der Bundeswehr München, 85577 Neubiberg, Germany.
Sci Rep. 2013;3:2511. doi: 10.1038/srep02511.
The mobility of damaged chromatin regions in the nucleus may affect the probability of mis-repair. In this work, live-cell observation and distance tracking of GFP-tagged DNA damage response protein MDC1 was used to study the random-walk behaviour of chromatin domains containing radiation-induced DNA double-strand breaks (DSB). Our measurements indicate a subdiffusion-type random walk process with similar time dependence for isolated and clustered DSBs that were induced by 20 MeV proton or 43 MeV carbon ion micro-irradiation. As compared to normal diffusion, subdiffusion enhances the probability that both ends of a DSB meet, thus promoting high efficiency DNA repair. It also limits their probability of long-range movements and thus lowers the probability of mis-rejoining and chromosome aberrations.
受损染色质区域在核内的流动性可能会影响错误修复的概率。在这项工作中，通过活细胞观察和 GFP 标记的 DNA 损伤反应蛋白 MDC1 的距离跟踪，研究了含有辐射诱导的 DNA 双链断裂 (DSB) 的染色质域的无规则行走行为。我们的测量结果表明，对于由 20 MeV 质子或 43 MeV 碳离子微照射诱导的孤立和簇集 DSB，存在类似时间依赖性的亚扩散型无规则行走过程。与正常扩散相比，亚扩散增强了 DSB 两端相遇的概率，从而促进了高效的 DNA 修复。它还限制了它们长距离运动的概率，从而降低了错误连接和染色体畸变的概率。
