DNA甲基化修饰变异在环境相关疾病发生发展中起重要作用。虽然现有研究已证明化学物暴露可引起DNA甲基化修饰改变，但多年来由于缺乏关键技术，无法阐明特定区域CpG位点甲基化变异对基因表达调控的影响。本研究拟利用CRISPR/dCas9 DNA甲基化编辑技术针对重要环境应答基因TRIM36、MGMT、p16、Rassf1A建立可调控甲基化修饰细胞模型。用典型环境致癌物处理细胞，通过比较对DNA损伤、氧化应激、细胞转化等关键毒性效应的影响，阐释特定CpG位点甲基化修饰变异的毒理学意义，并结合人群研究进一步验证甲基化调控与毒性效应之间的关联，为“DNA甲基化修饰—基因表达调控—细胞功能改变”因果关系链的建立提供直接证据，并提出甲基化核心修饰区域筛查和功能研究的框架和策略。DNA甲基化编辑细胞模型的建立为阐述环境表观遗传调控机制的理论以及表观遗传生物标志物预测环境化学物暴露风险的应用提供重要技术支撑

Aberrant DNA methylation plays important roles in development of environmental pollutants related diseases. Although it has been demonstrated that environmental chemical exposure can induce aberrant DNA methylation, the functional significance of CpG site-specific DNA methylation (including hypermethylation and demethylation) in regulating gene expression remains unclear due to the limitation of current technical method. In this project, CRISPR/Cas9-based DNA methylation editing method will be applied to establish cell models with engineering DNA methylation of specific genes, including TRIM36, MGMT, p16, and Rassf1A, based on our previous study. Typical environmental carcinogens will be selected to treat the cells at different DNA methylation states and the critical toxic effects such as DNA damage, oxidative stress, apoptosis, and cell transformation will be analyzed. By conducting the in vitro and in vivo studies, we will be able to explore the relationship of DNA methylation and toxic effects, providing direct evidence for the elucidation of causal relationship of DNA methylation, gene expression and cellular function changes. Meanwhile, we attempt to propose a framework and strategy for identification of key region for methylation modification and functional elaboration. In summary, the editable DNA methylation system will be essential for epigenetic mechanism study and for identification of epigenetic biomarkers for environmental health risk assessment.