Van Houten B, Masker W
Chem Biol Interact. 1985 Feb-Apr;53(1-2):89-97. doi: 10.1016/s0009-2797(85)80087-9.
DNA from bacteriophage T7 was treated with benzo[a]pyrene diol epoxide (BPDE) and the number of covalently bound adducts per T7 genome was determined. BPDE treated T7 DNA was then incubated in an in vitro DNA packaging system so as to form infective T7 phage. The observed reduced survival of these phage measured with Escherichia coli uvrA- indicator bacteria showed that the BPDE treated DNA was in fact utilized by the in vitro packaging system and that the resulting phage contained DNA damage caused by in vitro exposure to BPDE. T7 DNA damage by BPDE was also incubated in an in vitro DNA repair system that used partially purified uvrABC proteins from E. coli. Alkaline sucrose gradient analysis demonstrated that nicks were introduced into the damaged DNA and that these incisions were repaired to yield nearly intact DNA molecules of about the size of a T7 genome. Encapsulation of the repaired DNA with the packaging system yielded phage that showed higher survival than the unrepaired control when plated on uvrA- indicator bacteria.
用苯并[a]芘二醇环氧化物（BPDE）处理噬菌体T7的DNA，并测定每个T7基因组中与BPDE共价结合的加合物数量。然后将经BPDE处理的T7 DNA在体外DNA包装系统中孵育，以形成感染性T7噬菌体。用大肠杆菌uvrA-指示菌测定这些噬菌体的存活率降低，这表明经BPDE处理的DNA实际上被体外包装系统利用，并且产生的噬菌体含有因体外暴露于BPDE而导致的DNA损伤。经BPDE损伤的T7 DNA也在使用从大肠杆菌中部分纯化的uvrABC蛋白的体外DNA修复系统中孵育。碱性蔗糖梯度分析表明，损伤的DNA中引入了切口，并且这些切口被修复，从而产生了大小约为T7基因组的几乎完整的DNA分子。用包装系统将修复后的DNA包装成噬菌体，当接种在uvrA-指示菌上时，其存活率高于未修复的对照噬菌体。
