Defining the prion domain of PrP

描述（由申请人提供）：朊病毒疾病是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背后机制的基本事件。正常细胞异构体（PrPC）被错误折叠成富含β -sheet的致病异构体（PrPSc）。一旦形成，PrPSc似乎作为构象模板将额外的PrPC转化为PrPSc。大量证据表明，PrP中心区域的序列同源性是PrPSc与PrPC关联的必要特征，是PrPSc转化和繁殖的前奏，但具体涉及的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关联位点的研究无疑将确定抑制它们相互作用的方法，并为这些目前无法治愈的疾病提供治疗。因此，拟议的研究旨在定义PrP内的分子决定因素，主要是在假定的先验域中，这是有效的自结合和构象转移所必需的。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，以确定是否以及在哪里需要同源区域和残基来有效传播朊病毒菌株。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PrP潜在关键关联位点的特异性取代或缺失对prpsc样蛋白发育的影响。该模型不仅能够生成PrPSc样蛋白，而且能够支持至少两株PrPSc的重新生成，并证明了PrPSc到PrPC的构象转移。从这些研究中获得的信息将用于开发新的肽抑制剂，这些抑制剂被设计用于结合定义的“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传播，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.