CELLULAR RESPONSE TO DNA DAMAGE

这项研究的重点是细胞作出反应的机制 对DNA损害剂，如电离辐射，化学致癌物 和抗癌药物。该计划分为三个领域。这个 首先是对化学和生物化学的生化机制的分析。 物理试剂会诱发突变，这些突变可能会引发细胞沿着 通向恶性的道路。我们研究了突变的光谱 由一种DNA损伤剂诱导(因为在受损的DNA(加合物)中可能 会导致特定的突变。使用一种化学物质的组合 合成和重组DNA工具，构建病毒基因组 含有怀疑导致突变的加合物。跟随 在细菌或细菌中复制特异性修饰的基因组 我们决定哺乳动物细胞的类型、数量和遗传需求 用于每个被研究的病变的诱变。这项工作优先考虑 单个DNA加合物的诱变潜力。特定的DNA加合物 我们建议研究包括由氧化剂和电离产生的那些 辐射、简单烷化剂、黄曲霉毒素、B1、顺式- 二氨基二氯铂(顺铂)，4-氨基联苯，2-氨基-3，8- 二甲基咪唑94，5-f-喹恶啉(MeIQx)和氯乙烯。这个 拟议研究的第二个领域是对心绞痛机制的研究 抗癌药物顺铂的毒性。我们建议继续我们的 一类我们称之为“DRPs”(损伤)的蛋白质的研究 识别蛋白)。我们假设DRP参与了 顺铂的抗癌作用机制 模特们。第一个模型提出DRP在治疗上与 有效的顺铂加合物，并保护这些加合物免受DNA修复。 第二个模型是基于最近发现的一些DRP 具有必要的自然功能(其中一个是转录因子，hUBF)。 我们将检验这一假设，即顺式加合物将DRP从 它们的自然功能，因此扰乱了细胞的动态平衡。我们的 第三个建议的研究领域是设计一种新型的抗癌药物 代理通过上面提出的用于 顺铂。然而，在这种情况下，DNA结合域将被连接 会与加合物结合并保护其免受修复， 保存加合物，以便实现其最大的致命影响。 在正常(非肿瘤)细胞中，由于 肿瘤特异性蛋白的缺失。因此，在正常细胞中， 加合物的毒性作用将通过修复系统来减少 主持人。

This research program focuses on the mechanisms by which cells respond to DNA damaging agents such as ionizing radiation, chemical carcinogens and anticancer drugs. The program is divided into three areas. The first is an analysis of the biochemical mechanisms by which chemical and physical agents induce the mutations that presumably initiate cells along the pathway toward malignancy. We examine the spectrum of mutations induced by a DNA damaging agents (for in the damaged DNA (adducts) may give rise to specific mutations. Using a combination of chemical synthesis and recombinant DNA tools, viral genomes are constructed containing the adducts suspected to have caused the mutations. Following replication of the site specifically modified genomes in bacterial or mammalian cells we determine the type, amount and genetic requirements for mutagenesis by each lesion studied. This work priorities the mutagenic potential of individual DNA adducts. The specific DNA adducts we proposed to study include those produced by oxidants and ionizing radiation, simple alkylating agents, aflatoxin, B1, cis- diamminedichloroplatinum (II) (cisplatin), 4-aminobiphenyl, 2-amino-3,8- dimethylimidazo94,5-f0quinoxaline (MeIQx), and vinyl chloride. The second area of proposed research is an examination of the mechanism of toxicity by the anticancer drug cisplatin. We propose to continue our investigation of a class of proteins we have termed "DRPs" (for Damage Recognition Proteins). We hypothesize that DRPs are involved in the anticancer mechanism of cisplatin by either or both of the following models. The first model proposed that DRPs bind to therapeutically effective adducts of cisplatin and shield those adducts from DNA repair. The second model is based upon recent discovery that some of the DRPs have essential natural functions (one is the transcription factor, hUBF). We shall test the hypothesis that cisplating adducts divert DRPs from their natural functions, hence disrupting cellular homeostasis. Our third proposed area of investigation is the design of a novel anticancer agent that works by the "shielding" mechanism proposed above for cisplatin. In this case, however, a DNA binding domain will be linked to a protein will bind to the adduct and shield it from repair, preserving the adduct so that its maximal lethal impact can be realized. In normal (nontumor) cells no such protection will be afforded owing to the absence of the tumor specific protein. In normal cells, therefore, the toxic effect of the adduct will be reduced by the repair system of the host.