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Study of production mechanism of DNA clustered damage in aqueous solution

水溶液中DNA簇状损伤产生机制的研究

基本信息

批准号：
10480137
负责人：
KOBAYASHI Katsumi
金额：
$ 4.8万
依托单位：
High Energy Accelerator Research Organization
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10480137/
关键词：
synchrotron radiation DNA strand breaks monochromatic photons plasmid DNA scavenger スカべンジャー

项目摘要

Purpose of the study is to test our hypothesis that double strand breaks (DSB) of DNA, as a type of clustered damage, are mainly produced in a transiently-existing area (hot area) in which radicals are produced with high density by many energy deposition events in localized region. By changing the energy of monochromatic photons irradiated to aqueous samples, we can control the dimension of "hot area! Produced by the secondary photoelectron produced in water. We already observed that efficiency of DSB production become larger with lower energy photon, while single strand break (SSB) exhibit opposite dependence.During the term of the study, we have observed that the X-ray photon energy dependence of strand bread induction in the presence of high concentration of radical scavenger is the same with the case of the solution without scavenger. This seems to suggest that our hypothesis is effective in intracellular environment. In order to examine the production efficiency of double strand breaks in living cells, we have established a method to determine the number of double strand break in the cellular DNA without any treatment with restrictive digestion enzyme, by utilizing pulse field gel electrophoresis. We will soon have the answer of the test of our hypothesis.We have also investigated the production of DNA strand breaks by monochromatic vacuum UV photons (150 - 180 nm) in aqueous solution. We have found that VUV photon energy dependence of the production of DSB and SSB is different, indicating that production mechanism for the production of both type of strand breakage is different.

本研究的目的是验证我们的假设，即DNA的双链断裂（DSB），作为一种簇性损伤，主要是在一个短暂存在的区域（热区），其中的自由基产生的高密度的许多能量沉积事件在局部区域。通过改变单色光子照射到水溶液样品上的能量，我们可以控制“热区”的尺寸。由水中产生的二次光电子产生。我们已经观察到，随着能量的降低，DSB的产生效率变大，而单链断裂（SSB）则表现出相反的依赖性，在研究期间，我们观察到，在高浓度自由基清除剂存在下，链面包诱导的X射线光子能量依赖性与无清除剂的情况相同。这似乎表明我们的假设在细胞内环境中是有效的。为了检测活细胞中双链断裂的产生效率，我们建立了一种不经任何限制性消化酶处理，利用脉冲场凝胶电泳测定细胞DNA中双链断裂数的方法。我们还研究了水溶液中单色真空紫外光子（150 - 180 nm）引起DNA链断裂的情况。我们发现，真空紫外光子能量依赖的DSB和SSB的生产是不同的，表明生产机制的生产两种类型的链断裂是不同的。