Negative Modulation of Bystander DNA Repair Potential by X-Ray Targeted Tissue Volume in Arabidopsis thaliana
Negative Modulation of Bystander DNA Repair Potential by X-Ray Targeted Tissue Volume in Arabidopsis thaliana
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DOI：
10.1667/rr15314.1
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发表时间：
2019-05-01
影响因子：
3.4
通讯作者：
Bian, Po
中科院分区：
文献类型：
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作者：
Deng, Chenguang;Wu, Jingjing;Bian, Po
辐射诱导的旁观者效应（里贝）是指受照细胞向邻近细胞发出的旁观者信号级联反应，调节包括DNA损伤修复在内的多种生物学过程。然而，关于辐射靶向体积（命中细胞量）对旁观者细胞的DNA修复潜力的影响尚不清楚。在整个生物体的背景下理解这一点尤其重要，其中靶标通常由多种类型的细胞/组织组成。为了解决这个问题，模式植物拟南芥局部照射，和DNA修复潜力的旁观者根尖细胞进行评估的基础上，其辐射抗性随后的高剂量辐射，即辐射适应性反应（RAR）。我们发现，X射线照射A. 5戈伊处理后，根尖细胞发生RAR反应，对根生长和根细胞分裂的抑制减轻，DNA链断裂减少。我们还观察到在旁观者根尖细胞中同源重组（HR）和非同源末端连接（NHEJ）途径的修复效率的提高。我们进一步扩大了X射线靶体积，包括地上部分与上部分的主根，并将其与X射线照射的地上部分单独。比较分析显示，这些终点的RAR消失或降低;具体而言，HR的修复效率显著降低，表明辐射靶向体积负调节旁观者DNA修复潜力。相反，X射线单独照射主根上部不能诱导根尖细胞RAR。因此，我们建议，额外的X射线照射的上部的主根降低了旁观者DNA修复的潜力，可能是通过选择性地干扰负责HR修复的旁观者信号的传输。(C)2019辐射研究协会
Radiation-induced bystander effects (RIBE) entail a cascade of bystander signals produced by the hit cells to the neighboring cells to regulate various biological processes including DNA damage repair. However, there is little clarity regarding the effect of radiation-targeted volume (hit cell amount) on the DNA repair potential of the bystander cells. This is especially important to understand in the context of the whole organism, where the target usually consists of multiple types of cells/tissues. To address this question, model plant Arabidopsis thaliana was locally irradiated, and the DNA repair potential of bystander root-tip cells was assessed based on their radioresistance to subsequent high-dose radiation, i.e. radioadaptive responses (RAR). We found that X-ray irradiation of the aerial parts (AP) of A. thaliana seedlings (5 Gy) initiated RAR in the root-tip cells, which exhibited an alleviated repression of root growth and root cell division, and reduced amount of DNA strand breaks. We also observed an improvement in the repair efficiency of the homologous recombination (HR) and non-homologous end joining (NHEJ) pathways in the bystander root tip cells. We further expanded the X-ray targeted volume to include the aerial parts with upper parts of the primary root and compared it with X-ray irradiated aerial parts alone. Comparative analysis revealed that RAR for these end points either disappeared or decreased; specifically, the repair efficiency of HR was significantly reduced, indicating that radiation-targeted volume negatively modulates the bystander DNA repair potential. In contrast, X-ray irradiation of upper part of the primary root alone did not induce RAR of the root tip cells. Thus, we propose that additional X-ray irradiation of upper part of the primary root reduces the bystander DNA repair potential, possibly by selectively disturbing the transport of bystander signals responsible for HR repair. (C) 2019 by Radiation Research society