Radioresistance of GGG sequences to prompt strand break formation from direct-type radiation damage

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• 作者：Paul J. Black ; Adam S. Miller ; Jeffrey J. Hayes
• 关键词：DNA damage ; Guanine ; Radiation chemistry ; Radiosensitivity ; Gel electrophoresis ; Direct effect ; Ionizing radiation
• 刊名：Radiation and Environmental Biophysics
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：55
• 期：4
• 页码：411-422
• 全文大小：1,016 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Biophysics and Biomedical Physics
  Effects of Radiation and Radiation Protection
  Environmental Physics
  Environmental Computing and Modeling
  Ecosystems
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-2099
• 卷排序：55

文摘

As humans, we are constantly exposed to ionizing radiation from natural, man-made and cosmic sources which can damage DNA, leading to deleterious effects including cancer incidence. In this work, we introduce a method to monitor strand breaks resulting from damage due to the direct effect of ionizing radiation and provide evidence for sequence-dependent effects leading to strand breaks. To analyze only DNA strand breaks caused by radiation damage due to the direct effect of ionizing radiation, we combined an established technique to generate dehydrated DNA samples with a technique to analyze single-strand breaks on short oligonucleotide sequences via denaturing gel electrophoresis. We find that direct damage primarily results in a reduced number of strand breaks in guanine triplet regions (GGG) when compared to isolated guanine (G) bases with identical flanking base context. In addition, we observe strand break behavior possibly indicative of protection of guanine bases when flanked by pyrimidines and sensitization of guanine to strand break when flanked by adenine (A) bases in both isolated G and GGG cases. These observations provide insight into the strand break behavior in GGG regions damaged via the direct effect of ionizing radiation. In addition, this could be indicative of DNA sequences that are naturally more susceptible to strand break due to the direct effect of ionizing radiation.