TAU AND NEURODEGENERATION

在本提案中，我们描述了旨在确定tau基因突变导致与17号染色体相关的额颞叶痴呆和帕金森病（FTDP-17）相关的神经变性的机制的项目。此外，我们的目标是研究Tau在其他疾病的神经退行性变中的作用，包括进行性核上性麻痹（PSP）、阿尔茨海默病、皮克病和皮质基底变性（CBD）。PI的团队在今年6月的《自然》杂志上报告了与FTDP-17相关的tau缺失和剪接位点突变的鉴定。项目包括：FTD和Tauopathies的遗传学。该项目将使用遗传分析来检查tau基因变异与PSP、匹克病和CBD的可能关联。此外，本项目旨在确定3号染色体上也与FTD相关的基因。该基因座的突变产生了一种与FTD-17几乎无法区分的表型，因此鉴定该基因并确定其与tau的关系（如果有的话）非常重要。与tau基因突变相关的神经退行性疾病的病理生物学。tau基因中缺失突变的位置表明，这些突变可能影响tau结合微管的能力。该项目将使用体外微管蛋白结合试验来检验这一假设，并将研究突变对Tau蛋白聚合成原纤维的影响。此外，该项目将检查突变Tau在转染细胞中的影响，并分析项目3和项目4中产生的转基因小鼠大脑中的Tau。3和4重复Tau蛋白在体外和体内的作用分析。该项目将首先利用体外剪接试验来确定被FTDP-17剪接位点突变破坏的外显子10选择性剪接的调控。随后的研究将在体外、转染细胞和体内、基因靶向小鼠中进行，将检验4重复和3重复Tau在神经元功能中的不同作用。此外，基因靶向tau小鼠将被用于验证Tau4和3重复异构体的比例影响体内β毒性的假设。牛头病的转基因建模。该项目将利用转基因动物来模拟Tau缺失突变在体内的影响。将对表达野生型和突变型Tau cDNA构建的动物的大脑进行检测，以检测与FTDP-17相关的神经原纤维缠结和神经变性。此外，将研究表达人类基因组tau构建体的动物，以观察表达人类tau亚型对β敏感性的影响。这些项目将围绕神经病理学核心进行，其广泛的目标将是提供来自研究项目的人类患者和动物模型的大脑的详细形态学特征。

In this proposal we describe projects that aim to determine the mechanism by which mutations in the tau gene cause the neurodegeneration associated with Frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17). In addition we aim to examine the role of Tau in neurodegeneration in other diseases including Progressive supranuclear Palsy (PSP), Alzheimer's Disease, Pick's Disease and Cortico-basal degeneration (CBD). The PI's team reported the identification of missence and splice site mutations in tau, associated with FTDP-17 in the journal "Nature" in June of this year. The Projects are as follows: The Genetics of FTD and Tauopathies. This project will use genetic analysis to examine the possible association of variation in the tau gene with PSP, Pick's disease and CBD. In addition this project aims to identify the gene on chromosome 3 that is also linked with FTD. Mutations at this locus generate a phenotype that is almost indistinguishable from FTD-17 and thus it is important to identify this gene and determine its relationship, if any, with tau. Pathobiology of neurodegenerative disorders linked to mutations in the tau gene. The location of the missence mutations in the tau gene suggests that these likely affect the ability of Tau to bind microtubules. This project will examine this hypothesis using in vitro tubulin binding assays and will also study the effect of the mutations on the polymerization of Tau into fibrils. In addition this project will examine the effect of mutant Tau in transfected cells and will analyze the Tau from the brains of transgenic mice generated in projects 3 and 4. Analysis of the Role of 3 and 4 Repeat Tau in vitro and in vivo. This project will initially utilize in vitro splicing assays to determine the regulation of exon10 alternative splicing that is disrupted by the FTDP-17 splice site mutations. Subsequent studies that will performed in vitro, in transfected cells, and in vivo, in gene targeted mice, will examine the differing roles of 4 repeat and 3 repeat Tau in neuronal function. In addition the gene targeted tau mice will be used to test the hypothesis that the ratio of Tau4 and 3 repeat isoforms influences the toxicity of Abeta in vivo. Transgenic Modeling of Tauopathy. This project will utilize transgenic animals to model the effect of the Tau missence mutations in vivo. The brains of animals expressing wild type and mutant Tau cDNA constructs will be examined will be examined for the neurofibrillary tangles and neurodegeneration that are associated with FTDP-17. In addition animals expressing Human genomic tau constructs will be studied to see the effect of expressing Human Tau isoforms on Abeta sensitivity. These projects will operate around a Neuropathology Core whose broad goal will be to provide detailed morphological characterization of brains from Human patients and animal models that are derived from the research projects.