GENOTOXICITY IN HUMAN FETAL BRAIN, DERMIS, AND KIDNEY

本赠款提案的目的是进一步描述 人类胎儿细胞对遗传毒性物质的反应。 研究将 定量和比较，在来源于人胎脑、真皮和 肾脏：初始DNA损伤、修复、复制、结合和 DNA修复活动。 选择这些细胞是因为： 流行病学数据表明，神经系统和肾脏表现出 新生儿癌症的高水平，我们以前的研究表明， 这些人类胎儿细胞在以下方面表现出最显著的差异： 对遗传毒性物质的反应。 研究旨在进一步 通过将修复合成与 复制潜力加合持久性DNA修复酶 活动 三种不同类型的遗传毒素（紫外线 辐射，硫酸二甲酯和硫酸二乙酯，甲基和乙基亚硝基脲） 将用于生产不同类型的（胸苷二聚体，N7-烷基鸟嘌呤， N3-烷基腺嘌呤和06-烷基鸟嘌呤）和在N3-烷基腺嘌呤和06-烷基鸟嘌呤中的修饰程度 细胞DNA 每种修改的持久性将通过以下方式进行定量： 胸苷二聚体特异性N-糖基化酶/核酸内切酶和HPLC方法 用于分离烷基化碱。 使用特定放射性标记的DNA 底物N-糖基化酶，脱嘌呤核酸内切酶和 将在每种细胞类型中测定和比较烷基转移酶。 我们 具有独特的人类胎儿组织资源和新的培养方法， 技术. 因此，这些研究应进一步描述人类胎儿 细胞在人类胎儿发育期间对遗传毒性化合物作出反应。

The objective of this grant proposal is to further characterize the way in which human fetal cells respond to genotoxic agents. Studies will quantitate and compare, in cells derived from human fetal brain, dermis and kidney: the levels of initial DNA damage, repair, replication, binding and DNA repair activities. These cells were chosen because: human epidemiological data indicates that the nervous system and kidney exhibit high levels of cancer in the newborn, and our previous studies indicate that these human fetal cells exhibit the most significant differences in response to genotoxic agents. Studies are designed so as to further characterize these differences by correlating repair synthesis to replication potential to adduct persistence to DNA repair enzymatic activities. Genotoxin agents of three different types (ultraviolet radiation, dimethyl and diethyl sulfate, and methyl and ethyl nitrosourea) will be used to produce different types (thymidine dimers, N7-alkylguanine, N3-alkyladenine and 06-alkylguanine) and extents of modification in cellular DNA. Persistence of each modification will be quantitated by N-glycosylase/endonuclease specific for thymidine dimers and HPLC methods for separating alkylated bases. Using specifically radiolabeled DNA substrates the level of N-glycosylase, apurinic endonuclease and alkyltransferase will be determined and compared in each cell type. We have a unique resource of human fetal tissue and novel culturing techniques. These studies should thus further characterize how human fetal cells respond to genotoxic compounds during human fetal development.