Induction of DNA damage, including abasic sites, in plasmid DNA by carbon ion and X-ray irradiation
Induction of DNA damage, including abasic sites, in plasmid DNA by carbon ion and X-ray irradiation
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通过碳离子和 X 射线照射在质粒 DNA 中诱导 DNA 损伤，包括脱碱基位点
DOI：
10.1007/s00411-012-0447-4
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Shiina;T.
用低LET（13 keV/μm）或高LET（60 keV/μm）碳离子或X射线（4 keV/μm）在含有几种浓度的Tris（0.66-200 mM）的溶液中照射质粒pUC 18的DNA，以测定脱碱基（AP）位点的产量和清除能力的影响。用E.大肠杆菌核酸内切酶IV（Nfo）与SSB和基底病变进行了比较。在较高浓度的三羟甲基氨基甲烷，产量的单一或集群AP网站显着低于那些单一或集群的基础病变。单个AP位点和AP簇的相对产率分别小于10%和7%，在模仿细胞中的清道夫能力下产生的总损伤。AP位点的产率对清除能力的依赖性与提示链断裂的依赖性相似。在所测的清除能力范围内，碳离子或X射线诱导的AP位点与SSB的产率之比相对恒定在0.45 ± 0.15，而SSB与双链断裂（DSB）之比则表现出与清除能力和辐射质量的特征相关性。这些结果表明，水辐解产物的反应，推测OH自由基，与糖磷酸部分的DNA骨架诱导AP网站和SSB具有相似的效率。DNA的直接电离明显更多地参与DSB和碱基损伤簇的产生，而不是AP位点簇的产生。
DNA from plasmid pUC18 was irradiated with low-LET (13 keV/μm) or high-LET (60 keV/μm) carbon ions or X-rays (4 keV/μm) in solutions containing several concentrations of Tris (0.66–200 mM) to determine the yield of abasic (AP) sites and the effect of scavenging capacity. The yield of AP sites, detected as single-strand breaks (SSB) after digestion withE. coliendonuclease IV (Nfo), was compared with that of SSB and base lesions. At higher concentrations of Tris, the yields of single or clustered AP sites were significantly lower than those of single or clustered base lesions. The relative yields of single AP sites and AP clusters were less than 10 and 7 %, respectively, of the total damage produced at a scavenger capacity mimicking that in cells. The dependence of the yield of AP sites on scavenging capacity was similar to that of prompt strand breaks. The ratios of the yield of isolated AP sites to that of SSB induced by carbon ion or X-ray irradiation were relatively constant at 0.45 ± 0.15 over the tested range of scavenger capacity, although the ratio of SSB to double-strand breaks (DSB) showed the characteristic dependence on both scavenging capacity and radiation quality. These results indicate that the reaction of water radiolysis products, presumably OH radicals, with the sugar-phosphate moieties in the DNA backbone induces both AP sites and SSB with similar efficiency. Direct ionization of DNA is notably more involved in the production of DSB and base lesion clusters than in the production of AP site clusters.