Ribosome Dysfunction in Neurological Disorders

神经系统疾病中的核糖体功能障碍

• 批准号: 9213291
• 负责人: SUSAN L ACKERMAN
• 金额: $ 29.21万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9213291
• 关键词: Ribosome; Dysfunction; Neurological; Disorders

 DESCRIPTION (provided by applicant): Neurodegenerative disorders affect many millions of people around the world, particularly in the aging population. The vast majority of these diseases are not familial and the mutations that have been associated with rare familial forms of these disorders underscore the complexity of this group of diseases. To begin to understand this complexity, we have used forward genetic approaches to pinpoint the molecular pathways that maintain neuronal homeostasis in the aging mammalian brain. Using this approach we recently demonstrated that unresolved ribosome stalling is a novel mechanism for neurodegeneration. Despite the fundamental importance of translation, the cellular consequences of ribosome stalling in mammalian cells had been unknown until our discovery that a mutation in a novel mammalian ribosome rescue factor Gtpbp2 causes ataxia and degeneration of cerebellar granule cells, cortical and hippocampal neurons, and multiple retinal neurons. Importantly we demonstrated that loss of Gtpbp2 epistatically interacts with a mutation in a CNS- specific, cytoplasmic tRNAArgUCU in the widely used C57BL6/J (B6J) mouse strain to cause neurodegeneration. Our ribosome footprinting experiments revealed that loss of this tRNA led to low levels of ribosome stalling at Arginine AGA codons that was not associated with neurodegeneration. However, stalling was dramatically increased in the absence of Gtpbp2, demonstrating that this protein normally resolves ribosomal stalls. In this application we propose to determine the function of these and other ribosome rescue factors in neuron survival, the impact of increasing age on ribosome stalling in the brain, and additional molecular mechanisms which cause ribosome stalling in mammalian neurons. In Aim 1 we will determine the effects of loss of the ribosome rescue factors Gtpbp1, Hbs1l, and Pelo with- and without- tRNA deficiency. These studies will be complemented by novel computational methods to infer ribosomal locations at increased precision and ascertain mechanisms that distinguish strains using parameter-dependent simulations of the translation process. In Aim 2 we will determine the effects of aging on ribosome stalling and neurodegeneration in the brains of aged wild type and ribosome rescue mutant mice without the tRNA mutation and generate and analyze ribosome footprinting and RNA-Seq data from cerebella of aged mice. In Aim 3 we will investigate pathways that lead to cell death and determine their uniqueness for neurons. We will determine if deficiency of ubiquitously expressed tRNAs induces ribosome stalling and pathology in other organs, analyze the effects of the GCN2/ATF4 and P53 pathways on neurodegeneration, and identify additional modifier genes of neurodegeneration in Gtpbp2-/- mice. Together, we expect these studies to reveal the mechanisms by which dysregulation of translation elongation leads to cellular death and their specificity for neurodegenerative disease.

 描述（由适用提供）：神经退行性疾病会影响世界上数百万的人，尤其是在老龄化的人口中。这些疾病中的绝大多数不是家庭，在这组疾病的复杂性下与这些疾病的罕见农场形式相关的突变。为了开始理解这种复杂性，我们已经使用了远期遗传方法来查明在衰老的哺乳动物大脑中维持神经元稳态的分子途径。使用这种方法，我们最近证明未解决的核糖体失速是神经退行性的新机制。尽管翻译的基本重要性，但直到发现新型哺乳动物核糖体救援因子GTPBP2的突变引起性共济失调和小脑细胞，皮质和海马膜神经元和多种残留的新生膜和多种残留的新生动物和多种残留的新生动物，直到我们发现一种新型的哺乳动物核糖体救援因子GTPBP2的突变才发现，核糖体停滞的细胞后果一直未知。重要的是，我们证明了GTPBP2在CNS特异性的细胞质trnaargucu中与广泛使用的C57BL6/J（B6J）小鼠菌株中的突变相互作用，从而引起神经变性。我们的核糖体足迹实验表明，这种tRNA的损失导致与神经变性无关的精氨酸AGA密码子的核糖体停滞较低。然而，在没有GTPBP2的情况下，分期大大增加了，表明该蛋白质通常可以分辨出核糖体失速。在此应用中，我们建议确定这些和其他核糖体救援因子在神经元存活中的功能，年龄增加对大脑核糖体停滞的影响以及引起哺乳动物神经元核糖体停滞的其他分子机制。且无TRNA缺乏症。这些研究将通过新颖的计算方法完成，以提高精度和确定机制来推断核糖体位置，并使用翻译过程的参数依赖性模拟来区分菌株。在AIM 2中，我们将确定衰老对老年野生型和核糖体救援突变小鼠大脑中核糖体失速和神经退行性的影响，而无需tRNA突变，并产生和分析来自老年小鼠小脑的核糖体足迹和RNA-SEQ数据。在AIM 3中，我们将研究导致细胞死亡的途径并确定其对神经元的独特性。我们将确定普遍表达的TRNA的缺乏是否影响其他器官中的核糖体失速和病理，分析GCN2/ATF4和p53途径对神经变性的影响，并识别GTPBP2-/ - 小鼠GTPBPP2-/ - 小鼠中神经变性的其他修饰基因。我们期望这些研究共同揭示了翻译伸长失调导致细胞死亡及其对神经退行性疾病的特异性的机制。