1. UVA irradiation of BrU-substituted DNA in the presence of Hoechst 33258
- Author
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Hiroshi Sugiyama, Zutao Yu, Ji Hoon Han, Seiichiro Kizaki, and Abhijit Saha
- Subjects
0301 basic medicine ,5-Bromouracil ,DNA repair ,Clinical Biochemistry ,Pharmaceutical Science ,Context (language use) ,Biochemistry ,Electron transfer ,03 medical and health sciences ,chemistry.chemical_compound ,Bromouracil ,Drug Discovery ,Nucleosome ,DNA photoreaction ,Molecular Biology ,Micro-irradiation ,030102 biochemistry & molecular biology ,Chemistry ,Organic Chemistry ,Linker DNA ,Molecular biology ,Bisbenzimidazole ,030104 developmental biology ,Biophysics ,Molecular Medicine ,biological phenomena, cell phenomena, and immunity ,DNA - Abstract
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)-labelled 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 to BrU 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.
- Published
- 2018