p53 Stabilization and Neurodegeneration

描述（改编自申请人的摘要）：本项目的长期目标 该项目旨在确定导致肿瘤抑制因子p53的分子机制 在中枢神经系统中的蓄积和神经元变性。的 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通路的激活已经被证实。 在哺乳动物中枢神经系统中与神经元凋亡密切相关 系统在非神经细胞中，p53的丰度由一种 涉及Mdm 2癌蛋白的抑制性反馈环， 靶向p53进行泛素介导的降解。然而，事件负责 对于神经元中DNA损伤后p53的稳定性还没有描述。 我们的初步研究表明，p53积累的新机制， 泛素的下调，以及p53蛋白的定位， 凋亡神经元的核仁。因此，拟议的研究将使用 分子和生物化学方法来研究p53 稳定是某些类型神经元的基本组成部分， 部分由核仁功能受损介导的变性。具体 目的1将确定Mdm 2结合是否调节p53功能， 在动物和细胞培养模型中采用不同的方法来确定 p53积累是否是神经元细胞死亡所必需的。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将描述p53对细胞核仁功能的影响， 神经元变性最后，具体目标4将确定神经元是否 通过使p53降解恢复到脆弱的神经元来防止死亡。这些 研究应该大大增加我们对分子基础的理解， 某些类型的神经元细胞死亡和开发新的分子和 用于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.