Mechanistic Basis for Non-Canonical Translation in Neurological Disease

项目摘要 CAG重复扩张症是最常见的一类微卫星扩张性疾病。而当 CAG重复序列的规范翻译导致多谷氨酰胺蛋白的产生，这些扩张可以 还进行非规范重复相关的非AUG(RAN)翻译。在后面的过程中，翻译是 在没有Aug-或Aug-like起始密码子的情况下，跨多个阅读框架启动。虽然有几个因素 影响微卫星扩增中的规范翻译或RAN翻译的是 认识到，我们对翻译的潜在分子机制的理解 阅读框架是极其有限的。尽管有证据表明RNA结构在RAN翻译中起着关键作用，但我们 对促进RAN翻译的结构特征的知识极其有限。考察……的作用 在RNA结构的非规范翻译中，我采用了一种结构正向的方法来筛选多帧 翻译，通过它我识别了几个支持翻译的长非编码RNA(LncRNAs) 在没有微卫星重复扩增和Aug-Start密码子的情况下的多个读码框。这 数据表明，RNA转录有多种途径来支持多帧翻译，这具有重要的意义 对生物学、疾病和治疗学的影响。这项提案的首要目标是确定RNA 管理各种形式的多框架的结构、蛋白质网络和治疗相关的修饰物 翻译(MFT)。为了确定能够进行MFT的人类基因组的比例，我将利用一个 新颖的MFT报告系统进行全基因组筛选。利用候选MFT序列和CAG 与我已经确定的MFT lncRNAs一起重复扩展，我将确定细胞RNA结构 和促进非规范多帧翻译的蛋白质因子。我还将雇佣一名首创的 确定共同出现的规范和非规范的新的、治疗相关的修饰物的策略 在多个阅读框架中进行翻译。这些研究将使我们能够更好地了解 多帧翻译并确定有可能提供治疗效果的治疗策略 跨多个CAG重复扩张性疾病，适用于更广泛的神经系统疾病。 总之，这项研究为理解翻译多样性的新范式提供了一种创新的方法 将有助于更好地了解重复扩张性疾病的发病机制以及 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.