Double strand breaks induced by low doses of gamma rays or heavy ions: quantitation in nonradioactive human DNA.
Double strand breaks induced by low doses of gamma rays or heavy ions: quantitation in nonradioactive human DNA.
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低剂量伽马射线或重离子引起的双链断裂：非放射性人类 DNA 的定量。
DOI：
10.1006/abio.1996.0290
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Sutherland,JC
中科院分区：
文献类型：
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作者：
Sutherland,BM;Bennett,PV;Sutherland,JC
我们建立了一种定量测定101 μg非放射性人DNA中低频率（0-30个位点/109个碱基对）双链断裂的方法。用限制性内切核酸酶NotI消化未辐照或辐照的DNA，产生包括以约1.2-1.3 Mbp为中心的主要基团的切割片段。通过横向交变场电泳将DNA分子作为大小的函数分离。双链断裂的频率是直接从137 Cs γ或Fe ~（26+）（1.1GeV/核子）辐照诱导的1.2- 1.3-Mbp切割片段组中的数均分子长度的减少与相应的未辐照DNA样品相比来计算的。在0-10 cGy剂量范围内，双链断裂频率可方便地定量。计算出的人细胞DNA γ辐射每单位剂量的断裂频率（约4.6个双链断裂/109 bp/戈伊）在使用需要更高剂量的方法获得的数值范围内（2-8个位点/109 bp/戈伊）。
We have developed a method of quantitating low frequencies (0–30 sites/109base pairs) of double strand breaks in ∼1 μg of nonradioactive human DNA. Unirradiated or irradiated DNA is digested with the restriction endonucleaseNotI, producing cleavage fragments that include a major group centered at ∼1.2–1.3 Mbp. The DNA molecules are separated as a function of size by transverse alternating field electrophoresis. The frequency of double strand breaks is computed directly from the decrease in number average molecular length induced in the 1.2- to 1.3-Mbp cleavage fragment group by137Cs γ or Fe26+(1.1 GeV/nucleon) irradiation vs the corresponding unirradiated DNA samples. The double strand break frequency can be quantitated easily in the dose range of 0–10 cGy of γ rays. The frequency of breaks per unit dose calculated for γ irradiation of DNA in human cells (∼4.6 double strand breaks/109bp/Gy) is within the range of values obtained by others (2–8 sites/109bp/Gy) who used methods requiring higher doses.