UVA irradiation of Br U-substituted DNA in the presence of Hoechst 33258
UVA irradiation of Br U-substituted DNA in the presence of Hoechst 33258
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在 Hoechst 33258 存在下对 Br U 取代的 DNA 进行 UVA 照射
DOI：
10.1016/j.bmc.2017.11.011
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发表时间：
2018
影响因子：
3.5
通讯作者：
Sugiyama Hiroshi
中科院分区：
文献类型：
--
作者：
Saha Abhijit;Kizaki Seiichiro;Han Ji Hoon;Yu Zutao;Sugiyama Hiroshi
由于DNA系统的复杂性，我们对DNA修复的了解有限，因此开发了一种称为UVA微照射的技术，可用于可视化双链断裂（DSB）位点处DNA修复蛋白的募集。有趣的是，Hoechst 33258在微照射下用于敏化5-溴尿嘧啶（BrU）标记的DNA，引起有效的DSB。然而，UVA微辐射下DSB形成的分子基础仍然未知。在此，我们研究了UVA微辐射条件下DSB形成的机理。我们的研究结果表明，通过Hoechst 33258到BrU的电子转移产生的尿嘧啶-5-基自由基导致DNA优先在自身互补的5′-AABrUBrU-3′序列上切割，从而诱导DSB。我们还研究了核小体背景下的DNA切割，以更好地理解UVA微辐射在细胞样模型中的作用。我们发现，DNA切割发生在核心和连接DNA区域，虽然它的效率在核心DNA降低。
Given that our knowledge of DNA repair is limited because of the complexity of the DNA system, a technique called UVA micro-irradiation has been developed that can be used to visualize the recruitment of DNA repair proteins at double-strand break (DSB) sites. Interestingly, Hoechst 33258 was used under micro-irradiation to sensitize 5-bromouracil (BrU)-labeled DNA, causing efficient DSBs. However, the molecular basis of DSB formation under UVA micro-irradiation remains unknown. Herein, we investigated the mechanism of DSB formation under UVA micro-irradiation conditions. Our results suggest that the generation of a uracil-5-yl radical through electron transfer from Hoechst 33258 toBrU caused DNA cleavage preferentially at self-complementary 5′-AABrUBrU-3′ sequences to induce DSB. We also investigated the DNA cleavage in the context of the nucleosome to gain a better understanding of UVA micro-irradiation in a cell-like model. We found that DNA cleavage occurred in both core and linker DNA regions although its efficiency reduced in core DNA.