p53 Stabilization and Neurodegeneration

描述(改编自申请人的摘要)：该项目的长期目标 项目是确定导致肿瘤抑制基因P53的分子机制 中枢神经系统中的堆积和神经元变性。这个 申请是基于在进行研究时获得的新发现 与我们之前的NIH申请有关。P53通路的激活已经被 与哺乳动物中枢神经的神经细胞凋亡密切相关 系统。在非神经细胞中，P53的丰度受到 涉及与AND结合的MDM2癌蛋白的抑制反馈环 以P53为靶标进行泛素介导的降解。然而，负责的事件 DNA损伤后神经元中P53的稳定作用尚未被描述。 我们的初步研究证明了一种新的P53积聚机制 下调泛素表达及P53蛋白在卵巢癌组织中的定位 凋亡神经元的核仁。因此，拟议的研究将使用 用分子和生化方法研究P53基因的假说 稳定是某些类型神经元的重要组成部分 变性在一定程度上是由核仁功能受损引起的。特定的 目标1将确定MDM2结合是否调节P53功能，并将 在动物和细胞培养模型中使用不同的方法来确定 P53的积聚是否是神经细胞死亡所必需的。具体目标2 将研究P53是否调节泛素-蛋白酶体系统。 特异性目标3将表征P53对小鼠核仁功能的影响 神经元变性。最后，特定的目标4将决定神经元是否 通过恢复易受伤害的神经元的P53降解来防止死亡。这些 研究应该大大增加我们对分子基础的理解 某些类型的神经细胞死亡和新的分子和 神经退行性疾病的药物干预。

DESCRIPTION (Adapted from applicant's abstract): The long-term goal of this project is to define the molecular mechanisms leading to tumor suppressor p53 accumulation and neuronal degeneration in the central nervous system. The application is based on novel findings obtained while conducting studies related to our previous NIH application. Activation of the p53 pathway has been strongly implicated in neuronal apoptosis in the mammalian central nervous system. In non-neural cells p53 abundance is tightly controlled by an inhibitory feedback loop involving the Mdm2 oncoprotein which binds to and targets p53 for ubiquitin-mediated degradation. However, the events responsible for p53 stabilization following DNA damage in neurons have not been delineated. Our preliminary studies demonstrate a novel mechanism of p53 accumulation due to down regulation of ubiquitin, as well as localization of p53 protein in the nucleolus of apoptotic neurons. The proposed studies will therefore use molecular and biochemical approaches to investigate the hypothesis that p53 stabilization is an essential component of certain types of neuronal degeneration mediated, in part, by impairment of nucleolar function. Specific Aim 1 will determine whether Mdm2 binding modulates p53 function, and will employ different approaches in animal and cell culture models to determine whether p53 accumulation is essential for neuronal cell death. Specific Aim 2 will investigate whether p53 regulates the ubiquitin-proteasome system. Specific Aim 3 will characterize the effect of p53 on nucleolar function in neuronal degeneration. Finally, Specific Aim 4 will determine whether neuronal death is prevented by restoring p53 degradation to vulnerable neurons. These studies should significantly add to our understanding of the molecular basis of certain types of neuronal cell death and the development of novel molecular and pharmacological interventions for neurodegenerative diseases.