Molecular functions of the TRMT1 tRNA modification enzyme

项目总结 智力障碍(ID)是一种普遍存在的神经发育障碍，每100人中就有1人受到影响 世界各地的个人。最近的遗传学研究已经将大量的ID病例与 修饰核糖核酸化学结构的蛋白质。然而，tRNA的作用机制 影响大脑发育的修饰酶是个谜。在这里，我们将重点放在解密 TRNA甲基转移酶1(TRMT1)是一种重要的tRNA修饰酶 用于人类神经发育。携带TRMT1突变的个体表现出认知缺陷、生长发育 年龄早期的延迟和脑部异常。我们发现，TRMT1修饰的不止是 哺乳动物细胞中一半的tRNA，是某些tRNAs稳定所必需的。此外， 人类细胞中TRMT1的缺失导致增殖缺陷和相关途径的上调 在蛋白质折叠中。为了了解TRMT1在神经发育中的功能，我们生成了 一种新的TRMT1缺陷小鼠品系，表现出大脑和发育异常。 基于这些发现，我们认为TRMT1催化的修饰在 TRNAs的生物发生和功能，以确保蛋白质合成的适当水平 哺乳动物的生长和发育。在我们的第一个目标中，我们将使用新的tRNA测序 确定TRMT1催化的修饰在tRNA稳定性和 功能。在我们的第二个目标中，我们将使用核糖体图谱方法来破译 翻译中TRMT1催化的tRNA修饰。为了我们的最终目标，我们将定义 TRMT1在小鼠脑发育中的时空需求。总而言之，建议的 研究将在RNA修饰、蛋白质合成和 神经发育。

PROJECT SUMMARY Intellectual disability (ID) is a prevalent neurodevelopmental disorder affecting more than 1 in 100 individuals worldwide. Recent genetic studies have linked numerous cases of ID to variants in proteins that modify the chemical structure of RNA. However, the mechanisms by which tRNA modification enzymes influence brain development are enigmatic. Here, we focus on deciphering the biological role of tRNA methyltransferase 1 (TRMT1), a tRNA modification enzyme important for human neurodevelopment. Individuals with TRMT1 mutations exhibit cognitive deficits, growth delay and brain abnormalities early in age. We have discovered that TRMT1 modifies more than half of all tRNAs in mammalian cells and is required for the stability of certain tRNAs. Moreover, loss of TRMT1 in human cells causes proliferation defects and up-regulation of pathways involved in protein folding. To understand the function of TRMT1 in neurodevelopment, we have generated a novel TRMT1-deficient mouse strain which exhibits brain and developmental abnormalities. Based upon these findings, we propose that TRMT1-catalyzed modifications play a critical role in the biogenesis and function of tRNAs to ensure proper levels of protein synthesis during mammalian growth and development. In our first Aim, we will use new tRNA sequencing technologies to determine the role of TRMT1-catalyzed modifications in tRNA stability and function. In our second Aim, we will use ribosome profiling approaches to decipher the role of TRMT1-catalyzed tRNA modification in translation. For our final Aim, we will define the spatiotemporal requirement for TRMT1 in mouse brain development. Altogether, the proposed research will forge new connections between RNA modification, protein synthesis and neurodevelopment.