Structure of Triplet Repeat mRNA in Neurodegenerative Disease

三重核苷酸重复序列扩增突变导致进行性和致死性神经变性 亨廷顿病(HD)和2型脊髓小脑性共济失调(SCA2)等疾病。 虽然已经提出了许多机制来解释三胞胎的病理效应 重复扩增突变，这些疾病的分子基础仍然难以捉摸。多数 研究的重点是CAG编码的扩展的聚谷氨酰胺蛋白的毒性作用 重复着。然而，三联体重复rna最近被证明对神经元和 会导致疾病。这项研究将使用一种新的X射线足迹技术来可视化 活的神经细胞中扩增的亨廷顿蛋白基因结构异常。第一个目标是 确定正常和扩展的RNA在非应激和应激细胞中的结构 模仿HD的神经毒性效应。对不同的三联体重复mRNAs的比较将确定 容易形成神经毒性RNA结构的序列。第二个目标是调查如何 三联体重复RNA与细胞蛋白之间的相互作用导致神经毒性。在……里面 此外，一种结合CAG RNA重复序列的工具化合物将被测试其阻断能力 异常的mRNA结构。第三个目标是确定三联体的结构是否重复 络合物及其对信使核糖核酸相互作用组的影响解释了不同的敏感性。 神经元发生三联体重复突变。首次将X射线足迹技术应用于细胞内的mRNA 将把mRNAs的三维结构与三重重复疾病的病理联系起来， 并确定小分子工具化合物如何破坏活细胞中的这些结构。这个 长期目标是确定RNA-蛋白质相互作用的结构特征，以预测 神经毒性，这可以成为新疗法的靶点。

Triplet nucleotide repeat expansion mutations cause progressive and lethal neurodegenerative diseases such as Huntington's Disease (HD) and Spinocerebellar ataxia type 2 (SCA2). Although many mechanisms have been proposed to explain the pathological effects of triplet repeat expansion mutations, the molecular basis for these diseases remains elusive. Most research has focused on the toxic effects of expanded polyglutamine proteins encoded by CAG repeats. However, triplet repeat RNA has recently been shown to be toxic to neurons and to contribute to disease. This research will use a new X-ray footprinting technique to visualize the abnormal structure of the expanded huntingtin mRNA in living neuronal cells. The first aim is to determine the structures of normal and expanded RNA in unstressed and stressed cells that mimic the neurotoxic effects of HD. Comparisons of different triplet repeat mRNAs will identify sequences that readily form neurotoxic RNA structures. The second aim is to investigate how interactions between triplet repeat RNA and cellular proteins contribute to neurotoxicity. In addition, a tool compound that binds CAG RNA repeats will be tested for its ability to block abnormal mRNA structures. The third aim is to determine whether the structures of triplet repeat complexes and their effect on the mRNA interactome account for the varied sensitivity of neurons to triplet repeat mutations. This first application of X-ray footprinting to mRNAs in cells will link the three-dimensional structures of mRNAs with the pathology of triplet repeat diseases, and determine how small molecule tool compounds disrupt these structures in live cells. The long-term goal is to identify a structural signature of RNA-protein interactions that predict neurotoxicity and that can be targeted by new therapies.