Regulation of the SCA3 Disease Gene and Its Protein

描述（由申请人提供）： 这项建议的目的是研究转录和 引起多聚谷氨酰胺的疾病蛋白的翻译后调节 脊髓小脑性共济失调3型（SCA 3），一种被称为 共济失调蛋白-3。Polygln疾病主要是遗传性的，最终是致命的 神经退行性疾病，对此没有有效的治疗方法。一个统一 多聚谷氨酰胺病的病理特征是细胞内聚集的 疾病蛋白质，认为精确控制蛋白质稳态是至关重要的 神经元的存活因此，治疗策略应包括努力 目的：1）增强疾病蛋白的降解; 2）促进蛋白质 神经元的监视机制;和3）调节疾病基因表达。 为了实现这一目标，具体的目标是确定细胞通路 控制ataxin-3降解，并确定转录调控 SCA 3疾病基因MJD 1.具体而言，目标1中的研究希望 证明共济失调蛋白-3是蛋白酶体和半胱天冬酶的正常靶点， 蛋白水解，并确定蛋白酶体活性是否被抑制 积累的突变聚谷氨酰胺蛋白。目标2中的研究将检验这一假设 Ras/MEK通路调节MJD 1基因转录。各种 细胞和生物化学方法将被用来回答这些问题 包括代谢脉冲追踪试验、免疫共沉淀实验， 免疫印迹、定点诱变、细胞同步化和启动子 分析.本文的研究将进一步加深我们对ataxin-3的理解 生产和降解，也许导致治疗的发展， 这些目前无法治愈的疾病。

DESCRIPTION (provided by applicant): The aim of this proposal is to investigate the transcriptional and posttranslational regulation of the disease protein causing the polyglutamine (polygln) disease spinocerebellar ataxia type-3 (SCA3), a protein known as ataxin-3. Polygln diseases are dominantly inherited, ultimately fatal neurodegenerative diseases, for which there is no effective therapy. A unifying pathological feature of polygln diseases is intracellular aggregation of the disease protein, arguing that precise control of protein homeostasis is vital to neuronal survival. Therefore, therapeutic strategies should include efforts to: 1) enhance degradation of the disease protein; 2) boost the protein surveillance machinery of the neuron; and 3) modulate disease gene expression. Toward this goal, the specific aims are to determine the cellular pathways controlling ataxin-3 degradation, and to define the transcriptional regulation of the SCA3 disease gene, MJD1. Specifically, studies in aim 1 hope to demonstrate that ataxin-3 is a normal target for proteasome and caspase proteolysis, and determine whether the proteasomal activity is inhibited by accumulated, mutant polygln protein. Studies in aim 2 will test the hypothesis that the Ras/MEK pathway regulates MJD1 gene transcription. A variety of cellular and biochemical methods will be employed to answer these questions including metabolic pulse-chase assays, coimmunoprecipitation experiments, immunoblots, site-directed mutagenesis, cell synchronization, and promoter analysis. The studies proposed here will further our understanding of ataxin-3 production and degradation, perhaps leading to the development of therapies for these currently untreatable diseases.