Defining the prion domain of PrP

描述（由申请人提供）：朊病毒疾病是一种影响人类和动物的传染性神经退行性疾病家族。大量证据表明，朊病毒蛋白（PrP）的翻译后非共价修饰是这些疾病的基础机制中的基本事件。正常细胞亚型（PrPC）错误折叠为富含β折叠的致病性亚型（PrPSc）。一旦形成，PrPSc似乎充当构象模板以将额外的PrPC转化为PrPSc。相当多的证据支持PrP中心区域内的序列同源性作为PrPSc与PrPC结合的必要特征，作为PrPSc转化和传播的前奏，但涉及的确切片段和这种转化的序列决定因素尚不清楚。旨在了解PrPC和PrPSc相关位点的研究无疑将确定抑制其相互作用的方法，并为这些目前无法治疗的疾病提供治疗。因此，拟议的研究旨在定义PrP内的分子决定簇，主要是在推定的先验域内，这是有效的自缔合和构象转移所需的。我们将主要利用表达多态性PrP基因的转基因小鼠作为各种散发性和遗传性人类朊病毒疾病的宿主，以确定朊病毒株有效传播所需的同源区域和残基。此外，一种新的基于酵母的朊病毒疾病模型将被广泛用于研究在PrP的潜在关键关联位点处的特定取代或缺失对PrPSC样蛋白的发展的影响。这种强大的模型不仅能够产生prpSC样蛋白，而且可以支持至少两种PrPSc菌株的从头产生，并证明PrPSc到PrPC的构象转移。从这些研究中获得的信息将被应用于开发新的肽抑制剂，这些肽抑制剂被设计为结合到定义的“朊病毒结构域”内的关键位点，并阻止PrP的额外结合。随着欧洲牛海绵状脑病的持续威胁，以及目前鹿和麋鹿慢性消耗性疾病在美国的蔓延，这些研究是迫切需要的。

DESCRIPTION (provided by applicant): The prion diseases are a family of transmissible neurodegenerative disorders that affect humans and animals. A large body of evidence argues that a post-translational, non-covalent modification of the prion protein (PrP) is the fundamental event in the mechanism underlying these diseases. The normal cellular isoform (PrPC) is misfolded to the beta-sheet rich pathogenic isoform (PrPSc). Once formed, PrPSc appears to act as a conformational template to convert additional PrPC to PrPSc. Considerable evidence supports sequence homology within the central region of PrP as a necessary feature in the association of PrPSc with PrPC as a prelude to conversion and propagation of PrPSc, but the exact segment(s) involved and the sequence determinants for this conversion are unknown. Studies targeted at understanding the site(s) of association of PrPC and PrPSc will no doubt define ways to inhibit their interaction and provide treatment for these currently untreatable diseases. The proposed studies are designed, therefore, to define the molecular determinants within PrP, and primarily within the putative priori domain, that are required for efficient self-association and conformational transfer. We will primarily utilize transgenic mice that express polymorphic PrP genes to act as hosts for a variety of sporadic and genetic human prion diseases to determine if and where homologous regions and residues are required for efficient transmission of prion strain. In addition a novel yeast-based model of prion disease will be extensively utilized to study the effect of specific substitutions or deletions at potentially critical association sites of PrP on the development of PrPSC-like protein. This powerful model is not only capable of generating prpSC-Iike protein, but can support the de novo generation of at least two strains of PrPSc so, and demonstrate conformational transference of PrPSc to PrPC. The information gained from these studies will then be applied to the development of novel peptide inhibitors that are designed to bind to critical sites within the defined "prion domain" and halt additional binding of PrP. With the continued threat of bovine spongiform encephalopathy in Europe, and the current spread of chronic wasting disease of deer and elk in the U.S., these studies are urgently needed.