Pathogenesis of Neurodegenerative Diseases Caused by Mutations in Senataxin

描述(申请人提供)：本提案的目标是了解Sen1解旋酶在终止RNA聚合酶II(PolII)转录本中的作用，并确定人类Sen1同源物Senataxin(SETX)的突变如何导致神经退行性疾病共济失调-动眼运动性失用症2型(AOA2)和肌萎缩侧索硬化症4型(ALS4)。基于酵母模型，我们认为SETX突变通过破坏转录终止而导致人类疾病。因此，我们想要确定Sen1/SETX解旋酶在转录终止中的确切功能，以及这些功能在疾病中被破坏的方式。该基金的第一个目的是更多地了解酵母Sen1在转录终止中的作用，以及转录终止机制的其他组件对其的调节。我们将确定Sen1是通过直接作用终止PolII，还是通过其对小核仁核糖核蛋白(SnoRNP)组装的影响间接终止PolII。我们将通过分析snoRNP颗粒在次优细胞Sen1水平下的蛋白质和RNA组成来实现这一点。接下来，我们将确定Sen1基因突变导致细胞死亡的机制。这将通过减轻snoRNA信息读入下游必需基因的启动子阻断效应来实现。如果目前被接受的假设是正确的，这应该会抑制与Sen1缺失相关的致命性。随后，我们将探索磷酸化在调节Sen1中的作用。第二个目的是鉴定酵母SEN1和人类SETX功能的共同特征。我们将亲和纯化SETX，并鉴定与其相关的蛋白质和转录本。我们还将探索这些关联是如何通过磷酸化来调节的。第三个目标是确定人类SETX突变导致疾病的机制。我们将定义SETX的突变如何改变其蛋白质和RNA结合特性，并研究SETX相关蛋白质的突变是否会导致与SETX突变类似的细胞代谢缺陷。我们相信，上述目标的实现将使我们更好地理解转录终止的调节和神经退行性疾病的发病机制。获得的有关SETX功能的信息可能会让我们设计出新的策略来逆转ALS4和AOA2等神经退行性疾病的进展。项目简介我们的工作将调查感觉神经毒素蛋白SETX的突变如何导致神经退行性疾病共济失调眼运动性失用症2型(AOA2)和肌萎缩侧索硬化症4型(ALS4)。所获得的知识可能会为逆转神经退行性疾病的进展提供新的策略。

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the role of the Sen1 helicase in termination of RNA Polymerase II (PolII) transcripts and to establish how mutations in the human homolog of Sen1, Senataxin (SETX), cause the neurodegenerative disorders Ataxia-Oculomotor-Apraxia type 2 (AOA2) and Amyotrophic Lateral Sclerosis Type 4 (ALS4). Based on the yeast model, we propose that SETX mutations cause human disease through disruption of transcriptional termination. Thus, we want to define the precise function of the Sen1/SETX helicases in transcriptional termination and the manner in which these functions are disrupted in disease. The first aim of the grant is to learn more about the role of yeast Sen1 in transcription termination and its regulation by other components of the transcription termination machinery. We will determine whether Sen1 terminates PolII by direct action, or indirectly via its effect on small nucleolar ribonucleoprotein (snoRNP) assembly. We will accomplish this via analysis of the protein and RNA composition of the snoRNP particles under suboptimal cellular Sen1 levels. Next, we will identify the mechanism of the cell death caused by mutations of Sen1. This will be accomplished through alleviating the promoter occlusion effect of snoRNA messages reading into downstream essential genes. If the currently accepted hypothesis is correct, this should suppress the lethality associated with Sen1 loss. Subsequently we will explore the role of phosphorylation in the regulation of Sen1. The second aim is to identify the shared characteristics of yeast Sen1 and human SETX function. We will affinity purify SETX and identify the proteins and transcripts that associate with it. We will also explore how these associations are regulated by phosphorylation. The third aim is to identify the mechanism by which mutations in human SETX cause disease. We will define how mutations in SETX change its protein and RNA binding properties and examine whether mutations in proteins that SETX associates with cause similar defects in cellular metabolism as mutations in SETX. We believe that accomplishment of the goals outlined above will lead to a better understanding of the regulation of transcriptional termination and the pathogenesis of neurodegenerative disorders. The information obtained about the function of SETX might allow us to devise new strategies to reverse the progression of neurodegenerative diseases like ALS4 and AOA2. Project Narrative Our work will investigate how mutations in the Senataxin protein, SETX, cause the neurodegenerative disorders Ataxia Oculomotor Apraxia type 2 (AOA2) and Amyotrophic Lateral Sclerosis Type 4 (ALS4). The knowledge gained might provide new strategies to reverse the progression of neurodegenerative diseases.