ABERRANT UBIQUITINYLATION IN AGED AND ALZHEIMER BRAIN

阿尔茨海默病是一种常见的、进行性的、不治之症和 最终导致中枢神经系统的法塔病。在 组织病理学层面，其特点是形成 神经原纤维缠结(NFT)和老年斑(SP)。在 超微结构水平，非同寻常的高度不解的成对螺旋 检测到细丝(PHF)。我们最近已经证明， 阿尔茨海默病患者的大脑表现出惊人的 不同区域神经纤维上异常泛素免疫反应 含有NFT和SP。极少量的泛素 免疫反应神经原纤维在正常老年人的大脑中可见， 年轻健康的脑组织中没有这样的特征。在……里面 初步实验我们已经定义了一个蛋白水解性片段 从成对的螺旋丝(PHF)制备，据信是 具有泛素功能的NFT的基本成分 免疫反应性，但比泛素大得多。这 必须来自PHF组分中的蛋白质，该蛋白质 泛素化。我们希望跟进这些有趣的事情 观察。 我们会： 1)使用免疫学、生化和分子生物学 识别母体分子的技术 衍生泛素免疫反应蛋白水解物片段。我们 然后就会知道这种蛋白质在正常大脑中是否存在， 如果它存在，如果它对应于正常的细胞蛋白质。 2)研究泛素免疫反应性的分布。 泛素受体蛋白的免疫反应性 其他已知或推测的NFT标志物的免疫反应性 全面了解其中每一项之间的关系 在NFT和PHF中相互标记。 这些研究将在分子方面定义泛素化的 NFT的组成部分，并将为审查 PHF的形成机制及其意义 在PHF形成中的泛素化，以及为什么 泛素化的NFT不会被降解。

Alzheimer's disease is a common, progressive, incurable and ultimately fata disease of the central nervous system. At the histopathological level it is characterized by the formation of neurofibrillary tangles (NFT) and senile plaques (SP). At the ultrastructural level, unusual highly insoluble paired helical filaments (PHF) are detected. We have recently shown that brains from patients with Alzheimer's disease exhibit striking and unusual ubiquitin immunoreactivity on neurofibrils in regions containing NFT and SP. Very small numbers of ubiquitin immunoreactive neurofibrils are seen in normal aged brain, and such profiles are absent from younger healthy brain tissue. In preliminary experiments we have defined a proteolytic fragment from paired helical filament (PHF) preparations, believed to be the essential constituents of NFT, which has ubiquitin immunoreactivity, but which is much larger than ubiquitin. This must be derived from a protein in PHF fractions which is ubiquitinylated. We wish to follow up these interesting observations. We will: 1) use immunlogical, biochemical and molecular biological techniques to identify the parent molecule from which the ubiquitin-immunoreactive proteolytic fragment is derived. We will then know if this protein is present or absent in normal brain, and if it is present, if it corresponds to a normal cellular protein. 2) study the distribution of ubiquitin immunoreactivity, immunoreactivity for the ubiquitin acceptor protein, and immunoreactivity for other known or putative NFT markers to build up a comprehensive view of the relationship of each of these markers to one another in NFT and PHF. These studies will define in molecular terms an ubiquitinylated component of NFT and will set the stage for an examination of the mechanisms of PHF formation, the significance of ubiquitinylation in PHF formation, and the reasons why the ubiquitinylated NFTs are not degraded.