Transfer RNA Dynamics During Neural Differentiation

神经分化过程中的转运RNA动力学 转运RNA（transfer RNAs，tRNAs）不仅不是固定的mRNA解码器，而且在基因的形成过程中起着动态的作用 表情例如，预期tRNA丰度会影响mRNA稳定性： 最佳密码子（由丰富的tRNA解码）是稳定的，而转录本富含非最佳密码子 （由罕见的tRNA解码）是不稳定的。我们将利用果蝇神经干细胞的分化来检验这个模型 细胞（神经母细胞）作为一个高度易处理的系统，与人类神经发育和神经 疾病我们假设成神经细胞及其神经元后代之间的tRNA水平不同， 影响mRNA稳定性和微调基因表达以满足每种细胞类型的需要。我们也 假设在神经分化过程中tRNA基因（tDNA）转录受两个非排他性 机制：通过神经特异性抑制剂广泛抑制RNA聚合酶III（RPOL 3）等 由于重叠RNA聚合酶II（RPOL 2）依赖性转录，RPOL 3的靶向抑制。我们 将通过定量体内的tRNA丰度、tRNA转录和mRNA衰变来测试这些假设 神经母细胞和神经元，结合药理学和遗传操作的预测调节剂， tDNA转录。我们将使用靶向的方法来确定差异tRNA表达的功能意义。 mRNA衰减、神经发育和行为测定中的tRNA敲低和过表达。这项工作 通过开发改变tRNA表达的新工具，包括 CRISPR / Cas9方法缺陷的tRNA表达与几种神经发育和 神经系统疾病，包括神经退行性疾病、多种形式的小头畸形和脑 癌的我们将利用我们在果蝇神经生物学和RNA生物学方面的专业知识， 了解调节正常发育的tRNA表达动态，当有缺陷时， 疾病。

Transfer RNA Dynamics During Neural Differentiation Far from serving as invariant mRNA decoders, transfer RNAs (tRNAs) play a dynamic role in shaping gene expression. For example, tRNA abundance is expected to affect mRNA stability: transcripts enriched in optimal codons (decoded by abundant tRNAs) are stable while transcripts enriched in non-optimal codons (decoded by rare tRNAs) are unstable. We will test this model using differentiation of Drosophila neural stem cells (neuroblasts) as a highly tractable system with relevance to human neurodevelopment and neurological disease. We hypothesize that tRNA levels differ between neuroblasts and their neuronal progeny, thereby influencing mRNA stability and fine-tuning gene expression to meet the needs of each cell type. We also hypothesize that tRNA gene (tDNA) transcription during neural differentiation is regulated by two non-exclusive mechanisms: widespread repression of RNA polymerase III (RPOL3) by a neural-specific inhibitor and more targeted repression of RPOL3 due to overlapping RNA polymerase II (RPOL2)-dependent transcription. We will test these hypotheses using quantification of tRNA abundance, tRNA transcription and mRNA decay in neuroblasts and neurons, combined with pharmacologic and genetic manipulation of predicted regulators of tDNA transcription. We will determine the functional significance of differential tRNA expression using targeted tRNA knockdown and overexpression in assays of mRNA decay, neurodevelopment and behavior. This work will be made possible through the development of novel tools for altering tRNA expression, including a CRISPR / Cas9-based approach. Defective tRNA expression is implicated in several neurodevelopmental and neurological diseases, including neurodegenerative diseases, multiple forms of microcephaly, and brain cancers. We will use our expertise in Drosophila neurobiology and RNA biology to significantly advance the understanding of tRNA expression dynamics that regulate normal development and, when defective, contribute to disease.