论文部分内容阅读
目的 探讨核蛋白在镍对DNA氧化和致突变中的作用机制。方法 分别用高效液相色谱 -电化学 (HLPC EC)方法和穿梭质粒 pZ189突变检测系统 ,观察二价镍 (NiCl2 )与叙利亚地鼠胚(SHE)细胞核蛋白相互作用对质粒DNA氧化 [8 羟基脱氧鸟苷 (8 OHdG)形成 ]和突变频率的影响。结果 (1)SHE细胞核蛋白的存在明显加剧由NiCl2 和H2 O2 引起的pZ189DNA氧化(8 OHdG/10 5dG量从 0 .2 8± 0 .0 5 3增加到 0 .49± 0 .0 5 2 ) ,使突变频率增加 (从 4.73× 10 -4 增至14.6 2× 10 -4 ) ,差异均有显著性 (P <0 .0 1) ;(2 )在未提供H2 O2 和其他氧化剂的条件下 ,仅氧化型的核蛋白 (由60 Co辐射产生 )与NiCl2 相互作用 ,才具有激发DNA氧化和致突变作用 (8 OHdG/10 5dG为0 .38± 0 .0 5 4,突变频率为 11.6 3× 10 -4 )。过氧化氢酶 (CAT)、Trolox和甘露醇等自由基清除剂具有明显的抑制DNA氧化和突变作用。非氧化型的正常核蛋白与NiCl2 作用未增加DNA氧化和自发突变频率。结论 核蛋白与二价镍的相互作用及核蛋白氧化是引发DNA氧化损害和致突变的重要因素之一。
Objective To investigate the role of nuclear proteins in the oxidation and mutagenesis of DNA by nickel. Methods High performance liquid chromatography - electrochemical method (HLPC EC) and shuttle plasmid pZ189 mutation detection system were used to observe the interaction of nucleolar proteins between NiCl2 and Syrian hamster embryo (SHE) Guanosine (8 OHdG) formation] and the frequency of mutations. Results (1) The presence of SHE nucleocapsid obviously aggravated the oxidation of pZ189 DNA induced by NiCl2 and H2O2 (the amount of 8 OHdG / 105dG increased from 0.28 ± 0.055 to 0.49 ± 0. 052) , The frequency of mutation increased from 4.73 × 10 -4 to 14.6 2 × 10 -4, the difference was significant (P <0.01); (2) In the absence of H2O2 and other oxidants , Only the oxidized nucleoprotein (produced by 60Co radiation) interacted with NiCl2 to stimulate DNA oxidization and mutagenicity (0 .38 ± 0. 054 for 8 OHdG / 105dG and 11.63 for mutation frequency × 10 -4). Free radical scavengers, such as catalase (CAT), Trolox and mannitol, significantly inhibited DNA oxidation and mutation. The effect of non-oxidized normal nucleoprotein and NiCl2 did not increase the frequency of DNA oxidation and spontaneous mutation. Conclusion The interaction of nuclear proteins with bivalent nickel and the oxidation of nuclear proteins are one of the important factors that cause DNA oxidative damage and mutagenesis.