POLY-ADP-RIBOSE AND REPAIR OF RADIATION INDUCED DAMAGE

目前存在的聚合物聚(ADP-核糖)是所有 真核生物。虽然许多研究表明， 这种聚合物参与修复由 电离辐射和其他物质，这种生物作用 聚合物在DNA修复中的作用仍不清楚。因此，终极的 这项研究的目的是确定这是什么性质的 这可能发生在哺乳动物细胞中。为了回答这个问题, 我们建议在中国仓鼠卵巢细胞中分离突变株 缺乏合成聚(ADP-核糖)和 确定这一过程的生理和生化后果 缺乏症。这些突变体将使用非选择性 一种对菌落进行原位检测的筛选方法 利用放射性底物(NAD)和 放射自显影。来自假定的酶缺乏症的活细胞 克隆将从尼龙布复制品中恢复并进行测试 用于无细胞提取物中的聚(ADP-核糖酶)活性。 将检查聚(ADP-核糖)聚合酶阴性突变体 对伽马射线和其他DNA的杀戮异常敏感 破坏性因素。那些产生增加的药物 敏感度也将通过电池进行敏感度检查- 周而复始。单链和双链DNA修复的动力学研究 将对那些产生增加的药物的中断进行检查 敏感度。还可以修复复制和取消计划DNA 将对合成进行研究。我们认为生物化学 聚(ADP)-核糖缺陷突变体的特性提供了 阐明这种聚合物在DNA修复中的作用的前景。

The polymer poly(ADP-ribose) is present is the nuclei of all eukaryotic organisms. While a number of studies have suggested the involvement of this polymer in the repair of damage produced by ionizing radiation and other agents, the biological role of this polymer in DNA repair still remains unclear. Thus, the ultimate goal of this research is to determine what the nature of this involvement might be in mammalian cells. To answer this question, we propose to isolate mutants in the Chinese hamster ovary cell which are deficient in the synthesis of poly(ADP-ribose) and determine the physiologic and biochemical consequences of this deficiency. These mutants will be isolated using a non-selective screening approach in which colonies are examined in situ for enzyme activity using radioactive substrate (NAD) and autoradiography. Viable cells from putative enzyme-deficient colonies will be recovered from nylon cloth replicas and tested for poly(ADP-ribose) enzyme activity in cell free extracts. Poly(ADP-ribose) polymerase negative mutants will be examined for abnormal sensitivity to killing by gamma-rays and other DNA damaging agents. Those agents which produce an increase in sensitivity will also be examined for sensitivity through the cell- cycle. The kinetics of repair of single-and double-strand DNA breaks will be examined for those agents which produced increased sensitivities. Also repair replication and unschedule DNA synthesis will be examined. We believe that biochemical characterization of a poly(ADP)-ribose-deficient mutant offers the prospect of elucidating the role of this polymer in DNA repair.