Function of the DRPLA Gene Product Atrophin

该项目的目标是阐明atrophin蛋白的功能，该蛋白的突变是神经退行性疾病齿状静脉-苍白球萎缩症（DRPLA）的基础。这些突变是蛋白质内聚谷氨酰胺重复基序（由mRNA中的CAG三核苷酸重复序列编码）的扩展，使DRPLA成为几种已知的“谷氨酰胺重复紊乱”之一。在这组神经退行性疾病中，许多不同蛋白质中聚谷氨酰胺重复序列的扩增导致了各种疾病表型。然而，尽管DRPLA和其他疾病的差异细胞死亡模式相对有限，但该基因产物广泛分布于中枢神经系统和外周组织，其正常功能和疾病机制在很大程度上尚不清楚。DRPLA基因产物atrophin作为模型蛋白具有许多优点；它是亲水的，中等大小，并包含一些有趣的肽基序，这可能是重要的功能。本研究将通过四个具体目的来研究atrophin的功能。首先，将产生针对纯化萎缩蛋白、细菌融合蛋白和小合成肽的抗体。这些试剂将用于探测脑内萎缩蛋白的区域、细胞和亚细胞定位。然而，该项目的重点将是鉴定与atrophin相互作用的蛋白质，使用酵母双杂交筛选和亲和纯化技术。然后将评估聚谷氨酰胺重复扩增对任何已确定的相互作用的影响。在评估atrophin的功能时，关注蛋白-蛋白相互作用是至关重要的，因为由于多聚谷氨酰胺重复扩增而引起的相互作用的改变可能与DRPLA的发病机制有关。最后，将研究atrophin基因的不同选择性剪接对atrophin蛋白-蛋白相互作用的影响。遗传性疾病如DRPLA和其他谷氨酰胺重复疾病是神经学家特别感兴趣的，因为确定这些遗传性疾病的神经变性机制可能会揭示更常见的获得性神经退行性疾病如阿尔茨海默病、肌萎缩侧索硬化症和帕金森病的类似机制。在此研究过程中，由Morgan Sheng MBBS博士资助，候选人希望在分子遗传学和蛋白质生物化学的前沿技术方面接受培训，这将使他能够在分子神经学方面追求富有成效的职业生涯。

The goal of this project is to elucidate the function of the atrophin protein, mutations of which underlie the neurodegenerative disease dentatorubral-palliudoluysin atrophy (DRPLA). These mutations are expansions of a polyglutamine repeat motif (coded by CAG trinucleotide repeats in the mRNA) within the protein, making DRPLA one of several known "glutamine repeat disorders." In this group of neurodegenerative diseases, an expansion of polyglutamine repeat in a number of different proteins confers the various disease phenotypes. However, in spite of the relatively restricted patterns of differential cell death in DRPLA and the other disorders, the gene products are widely distributed in both the central nervous system and peripheral tissues, and not their normal functions and mechanisms of disease are largely unknown. The DRPLA gene product atrophin has a number of advantages as a model protein for study; it is hydrophilic, of moderate size, and contains a number of intriguing peptide motifs which may be important in its function. This study will examine the function of atrophin through four specific aims. First, antibodies will be generated against purified atrophin, bacterial fusion proteins, and small synthetic peptides. These regents will be used to probe the regional, cellular, and subcellular localizations of atrophin in brain. The focus of the project, however, will be the identification of proteins that interact with atrophin, using yeast two hybrid screening and affinity purification techniques. The effect of expansion of polyglutamine repeat on any identified interactions will then be assessed. A focus on protein-protein interactions is critical while evaluating the function of atrophin, as alterations in which interactions due to the polyglutamine repeat expansion may be involved in the pathogenesis of DRPLA. Finally, the effects of differential alternative splicing of the atrophin gene on atrophin protein-protein interactions will be examined. Hereditary disorders such as DRPLA and the other glutamine repeat diseases are of particular interest of neurologists, as identification of the mechanism of neurodegeneration in these hereditary disorders will likely shed light on similar mechanisms in the more common acquired neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis, and Parkinson's disease. During the course of this research, sponsored by Morgan Sheng MBBS, PhD, the candidate expects to be trained in the cutting edge techniques of molecular genetics and protein biochemistry that will empower him to pursue a productive career in molecular neurology.