重离子诱导的质粒DNA双链断裂分布研究  

Study on Plasmid DNA Damage Induced by Low-energy Neon Ion Irradiation

作　　者：王潇[1] 马秋峰[1,2] 靳根明[1] 李文建[1] 张红[1] 周利斌[1,2] 毛淑红[1,2] 邱嵘[1] 刘兵[1,2] 

机构地区：[1]中国科学院近代物理研究所 [2]中国科学院研究生院,北京100039

出　　处：《原子核物理评论》2005年第2期204-207,共4页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(30200070);甘肃省科学基金资助项目(ZS021A25009Z);中国科学院近代物理研究所所长基金资助项目(SZ030623)~~

摘　　要：利用能量为7.2MeV/u氖离子束辐照体外质粒DNA:pUC18,采用恒场凝胶电泳结合多功能荧光成像系统研究了pUC18双链断裂片段的分布。证实了双链断裂片段分布的非随机性,结果还发现DNA断裂后片段的交联现象,而且交联片段的分布也是非随机的。DNA is considered to be the most important and sensitive target in biological systems. In addition to the base damage, DNA strand breaks are the major lesion in the genome due to exposure to ionizing radiation. Mutation can be introduced to DNA as a result of enzymatic processing of DNA lesions or post-irradiation replication. However, the mechanisms of radiation-induced mutations are not well clarified at the molecular level. To study the effect on the simple plasmid DNA of heavy ion is even predominant or more feasible. Plasmid pUC18 DNA was prepared and irradiated by neon beam (7.199 MeV/u). The fragment distributions were determined by quantifying the ethidium bromide fluorescence. It can be seen that the shape of the intensity distributions is vastly different for the used radiation Dose. The distribution produced shows an excess of fragments particularly in 3 000 and 10 000 Gy the size range between 20—40 kbp and 20—50 bp. This clustering of double-stranded fragments might be influenced by the higher order chromatin structure of genomic DNA. If so, DNA loop structures could correspond to the size range for which we observed DSB clustering. Further studies aim at elucidating the heterogeneity of DSB induction within the genome and investigate the influence of chromatin structure on the non-random fragment distribution.

关 键 词：重离子 DNA双链断裂 非随机分布 质粒DNA 

分 类 号：Q7[生物学—分子生物学]