m6A/m7G RNA双重修饰介导的Trop2翻译调控及其在膀胱癌发生中的作用

RNA修饰是基因转录后调控的重要方式，其中mRNA的腺嘌呤甲基化(m6A)和tRNA的胸腺嘧啶甲基化（m7G）分别参与蛋白翻译调控过程。但该两种修饰如何协同调控特定靶基因翻译及其在肿瘤发生中的作用尚未明确。我们前期研究发现膀胱上皮细胞恶变过程中，m6A甲基化酶METTL3催化癌基因Trop2 mRNA的m6A修饰，促进其翻译；同时发现m7G甲基化酶METTL1亦调控Trop2蛋白表达，并促进膀胱上皮细胞恶变。据此，我们提出假设：METTL3催化的Trop2 mRNA m6A修饰和METTL1催化的tRNA m7G修饰双重调控Trop2翻译，促进膀胱癌的发生。本项目拟通过基因功能获得、缺失及拯救实验策略，利用RNA靶向修饰等技术深入探讨mRNA m6A和tRNA m7G修饰双重调控Trop2翻译机制及其对膀胱癌发生的促进作用。本项目为揭示膀胱癌发生的RNA表观遗传学机制提供重要理论基础。

RNA modification is an important manner in gene post-transcriptional regulation, in which adenine methylation (m6A) of mRNA and thymine methylation (m7G) of tRNA are involved in protein translation regulation, respectively. However, it is not clear how these two modifications synergistically regulate the translation of specific target gene and their role in carcinogenesis. Our previous study found that m6A methyltransferase METTL3 mediated the m6A modification of oncogene Trop2 mRNA in the process of malignant transformation of bladder epithelial cells, and promoted its translation. It was also found that m7G methyltransferase METTL1 regulates Trop2 protein expression and promotes bladder epithelial cells malignant transformation. Therefore, we hypothesized that both mettl3-mediated Trop2 mRNA m6A modification and mettl1-mediated tRNA m7G modification could regulate Trop2 translation and promote bladder cancer initiation. This project intends to explore the promoting effect of dual regulation of mRNA m6A and tRNA m7G Trop2 translation on bladder cancer initiation through gain-of-function, loss-of-function, rescue strategy and RNA editing technology for targeted modification. This project provides an important theoretical basis for revealing the RNA epigenetic mechanism of bladder cancer carcinogenesis.