Infectious prion generation by mouse transgenesis

描述（由申请人提供）：尽管广泛的研究集中在朊病毒疾病的病原上，但全长重组朊病毒蛋白（PrP）的传染性尚未得到证实，也没有传染性海绵状脑病（TSE）的遗传动物模型。基于对麋鹿PrP结构的核磁共振研究（K. Wuthrich实验室），我们开发了一种与野生型PrP有2个氨基酸差异的转基因小鼠模型，导致小鼠PrP结构改变。这种转基因小鼠有一个非常明确的、刚性的环，它将β薄片与α螺旋连接在一起。令人惊讶的是，转基因小鼠发展为自发性神经系统疾病，其外显率为100%，其特征是空泡改变、胶质细胞增生、小胶质细胞活化和脑内PrP斑块，类似于患有慢性消耗性疾病（CWD）的鹿和患有变异型克雅氏病（vCJD）或格斯特曼-斯特劳斯勒-沙因克综合征（GSS）的患者。我们的短期目标是确定新发育的斑块小鼠是否已经发展为传染性朊病毒疾病。如果具有传染性，这只转基因小鼠将是第一个由全长朊病毒蛋白遗传产生的传染性TSE的模型，并且将特别有趣，因为确切的结构变化已经被表征。此外，我们将阐明这种已知的结构变化是否改变了物种屏障。我们提出的研究目标的假设是，“刚性环”（RL） PrP是一种错误折叠的蛋白质，导致感染性淀粉样蛋白斑块和神经变性，类似于人类家族性TSE。拟建研究的目标是：(1)确定RL PrP是否具有传染性，以及这两种突变如何改变物种屏障；(2)表征由刚性环引起的神经退行性疾病，并了解神经退行性疾病的基础。使用RL小鼠进行的研究将是第一次通过转基因模拟已知的PrP结构特征来研究TSE的易感性和发病机制。通过阐明RL结构在TSE易感性和发病机制中的影响，我们希望对朊病毒诱导的神经变性和斑块形成、PrP转化以及朊病毒疾病中的物种屏障有基本的了解。

DESCRIPTION (provided by applicant): Although extensive research has focused on the etiologic agent in prion disease, infectivity of full length recombinant prion protein (PrP) has not yet been shown, and there is no genetic animal model of a transmissible spongiform encephalopathy (TSE). Based on structural PrP NMR studies of the elk PrP (K. Wuthrich laboratory), we have developed a transgenic mouse model with 2 amino acid differences from wild type PrP leading to a structural alteration in mouse PrP. The transgenic mouse has an extremely well- defined, rigid loop which connects a beta sheet with an alpha helix. Surprisingly, the transgenic mice develop a spontaneous neurologic disease with 100% penetrance characterized by vacuolar change, gliosis, microglial activation, and PrP plaques in the brain, similar to deer with chronic wasting disease (CWD) and patients with variant Creutzfeldt-Jakob disease (vCJD) or Gerstmann-Straussler-Scheinker syndrome (GSS). Our short term goal is to determine whether the newly developed mice with plaques have developed a transmissible prion disease. If infectious, this transgenic mouse would be the first model of an infectious genetically generated TSE from a full length prion protein, and would be particularly intriguing because the exact structural change has already been characterized. In addition, we will elucidate whether this known structural change has altered the species barrier. The hypothesis underlying our proposed research aims is that the "rigid loop" (RL) PrP is a misfolded protein which leads to infectious amyloid plaques and neurodegeneration, similar to a human familial TSE. The goals of the proposed studies are to: (1) determine whether the RL PrP is infectious and how the two mutations alter the species barrier and (2) characterize the neurodegenerative disease caused by the rigid loop and to understand the basis of the neurodegeneration. The studies using the described RL mouse would be the first time a known structural feature of PrP is modeled by transgenesis to study TSE susceptibility and pathogenesis. By elucidating the impact of the RL structure in TSE susceptibility and pathogenesis, we hope to gain basic insights into prion induced neurodegeneration and plaque formation, PrP conversion, and species barriers in prion disease.