腺嘌呤甲基化(m6A)是高等生物中一种主要的RNA修饰，亦是生命科学新的研究热点；其可能参与mRNA剪接、运输等加工代谢过程，但确切生物学功能，特别在化学致癌中的作用尚未明确。申请者前期研究发现在镍、镉诱导的细胞恶性转化中m6A RNA甲基化水平和甲基转移酶METTL3表达显著改变，提示RNA甲基化可能涉及镍、镉诱导的细胞恶性转化。本课题拟通过RNA甲基化免疫沉淀、逆转录单分子实时检测等技术证实镍、镉诱导细胞恶变特异的差异RNA甲基化基因；利用基因功能获得和缺失策略研究METTL3和差异RNA甲基化基因在镍、镉诱导细胞恶变中的作用；应用RNA免疫沉淀、可变剪接分析等技术深入探讨差异RNA甲基化对其mRNA稳定性、异构体转换等下游生物学效应的影响及其致癌的分子机制。本研究将从表观转录组学这一崭新的视角探讨镍、镉致癌的作用机制，为多阶段致癌过程中筛选特异性的生物学标记提供重要的理论依据。

N6-methyladenosine (m6A) is the most prevalent internal modification of RNA in higher eukaryotes, involving in mRNA splicing, mRNA nuclear export and mRNA stability and so on. It becomes new hotspot in life science. However, its biological function has remained obscure, especial its roles in chemical carcinogenesis. Recently, we found m6A RNA methylation and RNA methyltransferases METTL3 significantly changed during malignant transformation of epithelial cells induced by nickel and cadmium, suggesting RNA methylation might be involved in nickel and cadmium-induced cell transformation. In this project, we will further identify differential RNA methylation genes related to nickel and cadmium-induced cell malignant transformation by methylated RNA immunoprecipitation combined with sequencing (MeRIP-Seq), single-molecule real-time detection of reverse transcription. Moreover, we will investigate whether abnormal RNA methylation mediated by METTL3 contributes to nickel and cadmium-induced cell malignant transformation by gain-of-function and loss-of-function strategy. Furthermore, we will explore effects of differential RNA methylation on the regulation of various biological processes such as RNA stability and isoform switching, and carcinogenesis molecular mechanisms of abnormal RNA methylation. This project will not only reveal molecular mechanisms of nickel and cadmium carcinogenesis on the novel view of epitranscriptome, but provide important theoretical foundation for identifying specific biomarker in multiple stages of chemical carcinogenesis.