Molecular functions of the TRMT1 tRNA modification enzyme

项目摘要 智力残疾（ID）是一种普遍的神经发育障碍，影响超过1/100 世界各地的个人。最近的遗传学研究将许多ID病例与以下基因的变异联系起来： 改变RNA化学结构的蛋白质。然而，tRNA 修饰酶对大脑发育的影响是个谜。在这里，我们专注于破译 tRNA甲基转移酶1（TRMT 1）是一种重要tRNA修饰酶， 对人类神经发育的影响TRMT 1突变的个体表现出认知缺陷， 延迟和大脑异常的早期年龄。我们已经发现TRMT 1修饰了超过 它是哺乳动物细胞中所有tRNA的一半，并且是某些tRNA稳定性所必需的。此外，委员会认为， 人类细胞中TRMT 1的缺失导致增殖缺陷和相关途径的上调 in protein蛋白folding折叠.为了了解TRMT 1在神经发育中的功能，我们已经产生了 一种新的TRMT 1缺陷小鼠品系，其表现出脑和发育异常。 基于这些发现，我们提出TRMT 1催化的修饰在以下方面起着关键作用： tRNA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TRMT 1催化修饰在tRNA稳定性中的作用的技术， 功能在我们的第二个目标中，我们将使用核糖体分析方法来破译 TRMT 1催化翻译中的tRNA修饰对于我们的最终目标，我们将定义 TRMT 1在小鼠脑发育中时空需求总的来说， 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.