DNA DAMAGE BY ALKYLATING AGENTS AND THEIR REPAIR IN HUMAN TUMOR CELLS

R. S. Day，III，D. Yarosh和其他人已经表明，大约20%的 人肿瘤细胞系和病毒转化细胞系对 由于明显不存在烷基鸟嘌呤， 烷基转移酶这种酶可去除0-6位的烷基化损伤 而不是在DNA的其他部位。Dr. D. Yarosh合作 已经能够从人体肝脏中部分纯化出这种酶 并产生针对该蛋白质的多克隆抗体。研究已经 开始开发针对这种蛋白质的单克隆抗体。高 亲和抗体，我们将能够进一步纯化这种蛋白质。与 充分纯化，可获得部分氨基酸序列， 用于合成寡核苷酸探针，其将用于筛选 人肝cDNA文库。这种抗体也可以用来筛选 人肝cDNA表达文库。

R. S. Day, III, D. Yarosh, and others have shown that approximately 20% of human tumor lines and viral transformed lines are hypersensitive to alkylating agents due to an apparent absence of alkylguanine alkyltransferase. This enzyme removes alkylation damage at the 0-6 position of guanine but not at other sites in DNA. Dr. D. Yarosh in collaboration with our unit has been able to partially purify the enzyme from human liver and raise polyclonal antibodies to this protein. Studies have been initiated to develop monoclonal antibodies to this protein. With high affinity antibodies, we will be able to further purify this protein. With sufficient purification, partial amino acid sequence can be obtained and used to synthesize oligonucleotide probes which will be used to screen human liver cDNA libraries. Such antibodies can also be used to screen human liver cDNA expression libraries.