TRANSGENIC STUDIES OF AMYOTROPHIC LATERAL SCLEROSIS

描述（改编自申请人的摘要）：本项目的目标是 研究神经变性的致病机制， 肌萎缩侧索硬化症（ALS）的转基因小鼠模型。我们 应用程序有两个直接的目的：第一个是取代两个免费的 突变的人SOD 1蛋白中的半胱氨酸残基，以测试游离-SH的作用 在ALS中观察到的细胞内聚集体的形成。第二 其目的是确定仍能导致ALS的最小SOD 1片段， 转基因小鼠 目的1：大约20%的家族性ALS病例是由以下基因突变引起的： Cu/Zn超氧化物歧化酶基因（SOD 1）。过度表达的转基因小鼠 突变SOD 1发展出ALS样表型和运动神经元变性。一 人类SOD 1相关ALS和ALS的病理学共同特征 （SOD 1）小鼠模型中存在SOD 1-免疫反应性包涵体或 聚集在大脑和脊髓的神经元中。这些夹杂物/聚集体 被认为是ALS中运动神经元死亡的重要因素。测试 这些内含物/聚集体可能由二硫键形成的假设 通过SOD 1中一个或两个游离半胱氨酸的游离-SH基团的相互作用， 我们建议开发一种新的转基因小鼠模型， SOD 1（C6A/C111S/G93A）。在该转基因小鼠模型中，两个游离的半胱氨酸在 人SOD 1被丙氨酸和丝氨酸取代。没有 包涵体/聚集体的存在将表明游离半胱氨酸的作用; 疾病以及夹杂物/聚集物可能表明 游离半胱氨酸（-SH基团）。 目的2：我们最近建立了一种新的转基因小鼠模型， SOD 1截短突变（L126 Z）。这些小鼠形成了典型的ALS样 表型和病理学。这些结果提供了实验证据， 仅SOD 1多肽的一部分，而不是整个SOD 1蛋白， 足以产生神经元毒性并导致运动神经元 退化我们计划定义最小片段的SOD 1必需的 毒性，以便进一步研究ALS的发病机制， 方便。为了实现这一目标，我们建议开发额外的转基因 小鼠品系相继过表达较小的SOD 1片段， 多肽来确定导致ALS的SOD 1的最小片段。

DESCRIPTION (Adapted from applicant's abstract): The goal of this project is to investigate the pathogenic mechanisms underlying the neurodegeneration of amyotrophic lateral sclerosis (ALS) using transgenic mouse models. Our application has two immediate Aims: The first one is to replace the two free cysteine residues in mutant human SOD 1 protein to test the role of free -SH groups in the formation of intracellular aggregates noted in ALS. The second aim is to define the smallest fragment of SOD 1 that would still cause ALS in transgenic mice. AIM 1: About 20 percent of the familial ALS cases are caused by mutations in Cu/Zn superoxide dismutase gene (SOD 1). Transgenic mice that over express mutant SOD 1 develop an ALS-like phenotype and motor neuron degeneration. A common feature in the pathology of both human SOD1-linked ALS and the ALS (SOD1) mouse models is the presence of the SOD 1-inimunoreactive inclusions or aggregates in neurons of the brain and spinal cord. These inclusions/aggregates are thought to be important elements in motor neuron death in ALS. To test the hypothesis that these inclusions/aggregates may be formed by disulfide bonds through interaction of free -SH groups of one or both free cysteines in SOD 1, we propose to develop new transgenic mouse model that over expresses a mutated SOD 1 (C6A/C1 1 1S/G93A). In this transgenic mouse model, two free cysteines in human SOD1 are replaced by an alanine and a serine. Absence of inclusions/aggregates will indicate a role for free cysteines; Absence of disease as well as inclusions/aggregates may indicate a causative role of the free cysteines (-SH groups). AIM 2: We recently made a new transgenic mouse model that over expresses a truncation mutation in SOD 1 (L126Z). These mice developed a typical ALS-like phenotype and pathology. These results provide the experimental evidence that only a part of the SOD1 polypeptide, rather than entire SOD1 protein, is sufficient to produce the neuronal toxicity and cause motor neuron degeneration. We plan to define the minimum fragment of SOD 1 essential for toxicity so that further studies into the pathogenesis of ALS may be facilitated. To achieve this goal we propose to develop additional transgenic mouse lines that over express successively smaller fragments of SOD 1 polypeptide to determine the smallest segment of SOD 1 that causes ALS.