Mechanistic Basis for Non-Canonical Translation in Neurological Disease

项目摘要 CAG重复扩增疾病是最常见的一类微卫星扩增疾病。而 CAG重复序列的典型翻译导致多聚谷氨酰胺蛋白的产生，这些扩增可以 也经历非典型重复相关的非AUG（RAN）翻译。在后期的翻译过程中， 在不存在AUG或AUG样起始密码子的情况下跨多个阅读框起始。虽然有一些因素 影响微卫星扩增或RAN翻译的规范翻译， 确定，我们的理解的基础分子机制，负责翻译在多个 阅读帧非常有限。尽管有证据表明RNA结构在RAN翻译中起着关键作用， 促进RAN翻译的结构特征的知识是极其有限的。审查的作用 在RNA结构的非规范翻译中，我采用了结构正向的方法来筛选多框架 翻译，通过它我确定了几个长的非编码RNA（lncRNA），支持翻译， 多个阅读框，同时不存在微卫星重复扩增和AUC起始密码子。这 数据表明，RNA转录本支持多框翻译的多种途径，这具有重要的意义。 对生物学、疾病和治疗学的影响。该提案的首要目标是确定RNA 结构，蛋白质网络和治疗相关的修饰符，控制各种形式的多框架 翻译（MFT）。为了确定能够进行MFT的人类基因组的比例，我将利用 新的MFT报告系统进行全基因组筛选。利用候选MFT序列和CAG 重复扩增沿着我已经鉴定的MFT lncRNA，我将确定细胞RNA结构 和促进非规范多框架翻译的蛋白质因子。我也会雇佣一个 鉴定新的、治疗相关的共现的规范和非规范修饰剂的策略 多个阅读框架中的翻译。这些研究将有助于更好地了解 多框架翻译，并确定有可能提供治疗效果的治疗策略 跨多种CAG重复扩增疾病，适用于更广泛的神经系统疾病。 总之，本研究为理解翻译多样性的新范式提供了一种创新的方法 并将使人们能够更好地了解重复扩增疾病的发病机制， 阐明MFT最适合于治疗干预的方面。

Project Summary CAG repeat expansion diseases are the most common class of microsatellite expansion disorders. While canonical translation of the CAG repeat leads to the production of polyglutamine proteins, these expansions can also undergo non-canonical repeat associated non-AUG (RAN) translation. In the later process, translation is initiated across multiple reading frames in the absence of AUG- or AUG-like start codons. While a few factors that influence either canonical translation across microsatellite expansions or RAN translation have been identified, our understanding of the underlying molecular mechanisms responsible for translation in multiple reading frames is extremely limited. Despite evidence that RNA structure plays a key role in RAN translation our knowledge of the structural features that facilitate RAN translation is extremely limited. To examine the role of RNA structure in non-canonical translation, I used a structure-forward approach to screen for multi-frame translation, through which I identified several long non-coding RNAs (lncRNAs) that support translation in multiple reading frames in the absence of both microsatellite repeat expansions and AUG-start codons. This data suggests multiple avenues for RNA transcripts to support multi-frame translation, which has important implications in biology, disease, and therapeutics. The overarching goal of this proposal is to determine the RNA structures, protein networks and therapeutically relevant modifiers that govern various forms of multi-frame translation (MFT). To determine the proportion of the human genome capable of undergoing MFT, I will utilize a novel MFT reporter system to perform a genome-wide screen. Utilising candidate MFT sequences and CAG repeat expansions along with my already identified MFT lncRNAs, I will determine the cellular RNA structures and protein factors that facilitate non-canonical multi-frame translation. I will also employ a first-of-its-kind strategy to identify novel, therapeutically relevant modifiers of co-occurring canonical and non-canonical translation in multiple reading frames. These studies will enable a better understanding of the mechanism of multi-frame translation and identify therapeutic strategies that have the potential to provide therapeutic efficacy across multiple CAG repeat expansion diseases and be applicable to a wider range of neurological diseases. Together this research provides an innovative approach to understand a novel paradigm for translation diversity and will enable a better understanding of disease pathogenesis in repeat expansion diseases as well as elucidating the aspects of MFT most suitable to therapeutic intervention.