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

R.S.Day、III、D.Yarosh和其他人已经证明 大约20%的人类肿瘤细胞系和病毒转化 LINE对烷基化试剂过敏是因为明显的 不存在烷基鸟嘌呤转移酶。我们已经能够 从人的肝脏中部分提纯酶。这种酶 去除鸟嘌呤06位上的烷基化损伤，但不 在DNA中的其他位置。我们计划进一步描述这一点 酶并将其提纯到氨基酸序列 所获得的信息。与D.Yarosh合作，人类 肝脏提取液被用来分离足够量的 这种蛋白质。特定RNA转录的差异 在Mer+和Mer-细胞系中进行了研究。使用 杂交消减，构建了一个cDNA文库 一个mer+细胞，它已经耗尽了与 配对的多细胞系。然而，当其他合并+和合并- 使用了线条，这种相关性不一致--即没有一条线 从转录本编码的cdna克隆一致地 与Mer-细胞系相比，Mer+含量丰富。

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 Alkytransferase. We have been able to partially purify the enzyme from human liver. This enzyme removes alkylation damage at the 06 position of guanine but not at other sites in DNA. We plan to further characterize this enzyme and purify it to the point where amino acid sequence information in obtained. In collaboration with D. Yarosh, human liver extracts are being used to isolate adequate quantities of this protein. Differences in the transcription of specific RNAs in mer+ and mer- cell lines were investigated. With hybridization subtraction, a cDNA library was constructed from a mer+ cell which has been depleted of sequences common to matched mer-cell lines. However, when other mer+ and mer- lines were used, this correlation was not consistent - i.e., none of the cDNA clones coded from a transcript consistently more abundant in mer+ compared to mer- cell lines.