Neurodevelopmental role of a tRNA methyltransferase underlying intellectual disability

项目总结 多水平的基因调控对神经系统的发育和功能至关重要。一批 已发现导致全球基因表达失调的突变不成比例地影响 神经系统，导致神经发育和神经退行性疾病。转移RNA(TRNA)， 它们识别密码子，并在生长的多肽中添加适当的氨基酸，可以动态调节 翻译。TRNA在转录后大量修饰，以调节其结构、稳定性和保真度。 ALKBH8是酵母tRNA甲基转移酶TRM9的两个后生动物同源物之一。停下来，误会 人类ALKBH8基因突变最近被证明在四个家庭中导致智力残疾。 然而，ALKBH8的S在神经系统中的作用尚不清楚。为了解决这个问题，我生成了NULL 发现ALKBH8调节突触的形成。我的初步数据显示 ALKBH8通过tRNA甲基化来限制氧化应激，从而减弱突触生长。 硒半胱氨酸，它产生罕见的第21种氨基酸硒半胱氨酸，用于合成硒蛋白。在AIM中 1，我将在果蝇中使用遗传学、药理学、成像学和生物信息学方法来定义 ALKBH8、硒蛋白和突触生长之间的联系，并研究人ALKBH8的影响 神经系统的突变。在AIM 2中，我将在我的论文工作中获得的技能基础上，通过 扩展为人源性多能干细胞(IPSCs)以模拟神经疾病和探测 潜在的治疗策略。 拟议的实验计划将提供对trna修饰如何调节基因的机械性见解。 在神经系统发育过程中的表达。拟议的培训计划将为我提供技术、 学术和专业技能将在我剩余的博士前培训期间和以后蓬勃发展 过渡到博士后职位。成功完成F99/K00 AIMS将使我处于一个独特的 在两个模型系统中研究神经发育障碍的潜在机制 互补优势，并为受影响的个人确定潜在的治疗方法。

PROJECT SUMMARY Gene regulation at multiple levels is critical for nervous system development and function. A number of mutations leading to global dysregulation of gene expression have been found to disproportionately affect the nervous system, leading to neurodevelopmental and neurodegenerative disorders. Transfer RNAs (tRNAs), which recognize codons and add the appropriate amino acid to growing polypeptides, can dynamically regulate translation. tRNAs are heavily post-transcriptionally modified to regulate their structure, stability, and fidelity. ALKBH8 is one of two metazoan homologs of the yeast tRNA methyltransferase TRM9. Stop and missense mutations in human ALKBH8 have recently been shown to cause intellectual disability in four families. However, ALKBH8’s role in the nervous system remains unknown. To address this, I have generated null alleles in Drosophila and found that ALKBH8 regulates synapse formation. My preliminary data suggest ALKBH8 attenuates synaptic growth by limiting oxidative stress through the methylation of tRNA- selenocysteine, which yields the rare 21st amino acid selenocysteine for the synthesis of selenoproteins. In AIM 1, I will employ genetic, pharmacological, imaging, and bioinformatic approaches in Drosophila to define the links between ALKBH8, selenoproteins, and synaptic growth and investigate the impact of a human ALKBH8 mutation in the nervous system. In AIM 2, I will build on the skills gained during my dissertation work by expanding into human-derived pluripotent stem cells (iPSCs) to model neurological disorders and probe potential treatment strategies. The proposed experimental plan will provide mechanistic insight into how tRNA modifications regulate gene expression during nervous system development. The proposed training plan will provide me with the technical, academic, and professional skillset to thrive for the remainder of my predoctoral training and beyond as I transition into a postdoctoral position. Successful completion of the F99/K00 aims will place me in a unique position to investigate mechanisms underlying neurodevelopment disorders in two model systems with complementary strengths and identify potential therapeutic treatments for affected individuals.