Screening of epimutagens using DNA repair system

表观遗传改变的异常是导致动物癌变和致畸的原因之一。性状的表观遗传变化伴随着责任基因启动子区胞嘧啶甲基化模式的变化。引起表观遗传变化的外源性化学物质被称为表观诱变剂。本研究试图建立一种筛选5-甲基胞嘧啶脱甲基化化学物质的检测方法。我们构建了一种方法，其中5-氮杂胞苷（5azaC）诱导的去甲基化可以通过绿色荧光或甲基亚硝基脲（MNU）抗性克隆的形成来检测，使用缺乏O 6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）表达的HeLaMR肿瘤细胞。证实了MGMT mRNA和蛋白在5-azaC诱导的MNU抗性细胞中的表达。 使用这种方法，可以在环境中的各种化学物质中检测出表突变体。

Abnormality of epigenetic changes is a cause of carcinogenesis and teratogenesis in the hjgher animals. Epigenetic changes in traits accompany the change in cytosine methylation patterns of the promoter region of the responsible genes. Exogenous chemicals causing the epigenetic changes are called epimutagens. In this study, the assay methods to screen chemicals causing demethylation of 5-methylcytosine were tried to establish. We constructed the method in which the 5-azacytidine (5azaC)-induced demethylation can be detected by green fluorescence or formation of methyl nitrosourea (MNU)- resistant colonies using HeLaMR tumor cells lacking expression of O6-methylguanene-DNA methyltransferase (MGMT). Expression of MGMT mRNA and protein in the 5-azaC-induced MNU-resistant cells were confirmed. Using this method, epimutagens would be detected among various chemicals in the environment.