Mechanism and functions of DALRD3-dependent tRNA modification

项目总结 TRNA修饰酶中的许多遗传变异与 毁灭性的神经发育和神经紊乱。然而，分子 支撑这些病理的机制尚不清楚。为什么会有这样的扰动 许多不同的tRNA修饰酶，从而改变为各种化学物质 它们催化的修饰似乎比其他器官对大脑的影响更大？至 为了解决这个问题，我们的实验室试图阐明trna的分子和细胞作用。 修饰酶对人类健康和疾病的影响。我们最近发现了一本小说 TRNA合成酶类似的模拟物，DALRD3，是特定化学修饰所必需的 在人类tRNA的子集中。我们的初步结果表明，依赖DALRD3的 修饰会影响tRNA的构象稳定性和功能。值得注意的是，我们还 在DALRD3基因中发现了一种常染色体隐性变异，它导致了 功能与神经功能紊乱的癫痫性脑病。基于这些 发现，我们认为DALRD3介导的修饰在正常的 在神经发育过程中对蛋白质合成具有重要作用的特定tRNA的功能。在……里面 我们的第一个目标是定义tRNA识别和修饰的要求 依赖于DALRD3及其同源tRNA底物。为了我们的第二个目标，我们将 测量依赖DALRD3的修饰对tRNA结构和功能的影响。 在我们的最终目标中，我们将确定依赖DALRD3的tRNA修饰在 通过核糖体图谱在大脑中进行全球蛋白质翻译。总括而言，建议的 这项研究将对理解tRNA修饰如何 影响正常的神经发育。尽管DALRD3在tRNA方面出人意料地发挥了作用 修改后，我们现在有了一个新的目标来探索针对个人的潜在疗法 患有与tRNA生物学有关的癫痫脑病。

PROJECT SUMMARY Numerous genetic variants in tRNA modification enzymes have been linked to devastating neurodevelopmental and neurological disorders. However, the molecular mechanisms underpinning these pathologies are unknown. Why is it that perturbations to many different tRNA modification enzymes and thus, changes to the various chemical modifications they catalyze, seem to affect the brain more so than other organs? To resolve this question, our lab seeks to elucidate the molecular and cellular roles of tRNA modification enzymes in human health and disease. We have recently uncovered a novel tRNA synthetase-like mimic, DALRD3, that is required for a specific chemical modification in a subset of human tRNAs. Our preliminary results suggest that the DALRD3-dependent modification impacts tRNA conformational stability and function. Notably, we have also identified an autosomal-recessive variant in the DALRD3 gene that causes loss of function and the neurological disorder epileptic encephalopathy. Based upon these findings, we propose that DALRD3-mediated modification plays a critical role in the proper function of specific tRNAs important for protein synthesis during neurodevelopment. In our first Aim, we will define the requirements for tRNA recognition and modification dependent in DALRD3 and its cognate tRNA substrates. For our second Aim, we will measure the impact of DALRD3-dependent modification on tRNA structure and function. In our final Aim, we will determine the role of DALRD3-dependent tRNA modification on global protein translation in the brain through ribosome profiling. In total, the proposed research will have broad implications in understanding how tRNA modifications can impact proper neurodevelopment. Although DALRD3 was an unexpected player in tRNA modification, we now have a new target to explore potential therapeutics for individuals suffering from epileptic encephalopathies linked to tRNA biology.