TRANSGENIC STUDIES OF AMYOTROPHIC LATERAL SCLEROSIS

描述(改编自申请者摘要)：本项目的目标是 探讨神经退行性变的发病机制 肌萎缩侧索硬化症(ALS)转基因小鼠模型。我们的 应用程序有两个直接目标：第一个目标是取代这两个免费的 半胱氨酸残基在突变型人SOD1蛋白中的作用 在肌萎缩侧索硬化症中注意到的细胞内聚集体的形成。第二 目的是确定仍然会导致ALS的SOD1的最小片段 转基因小鼠。 目的1：大约20%的家族性肌萎缩侧索硬化病例是由基因突变引起的 铜/锌超氧化物歧化酶基因(SOD1)。过度表达的转基因小鼠 突变型SOD1表现为肌萎缩侧索硬化症样表型和运动神经元变性。一个 人类SOD1连锁肌萎缩侧索硬化症和肌萎缩侧索硬化症的共同病理特征 (SOD1)小鼠模型是存在SOD1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/集料 被认为是ALS运动神经元死亡的重要因素。要测试 假设这些包裹体/聚集体可能由二硫键形成 通过SOD1中一个或两个自由半胱氨酸的自由-SH基团相互作用， 我们建议开发一种新的转基因小鼠模型，使其过表达突变的 SOD 1(C6A/C11S/G93A)。在这个转基因小鼠模型中，体内的两个游离半胱氨酸 人的SOD1被丙氨酸和丝氨酸取代。缺席 包裹体/聚集体将指示游离半胱氨酸的作用；缺少 疾病以及包涵体/聚集体可能表明 游离半胱氨酸组(-SH组)。 目的2：我们最近建立了一种新的转基因小鼠模型，该模型过表达一种 SOD1(L126Z)的截短突变。这些小鼠形成了典型的肌萎缩侧索硬化症样症 表型和病理学。这些结果提供了实验证据 只有SOD1多肽的一部分，而不是整个SOD1蛋白 足以产生神经元毒性并引起运动神经元 退化。我们计划定义SOD1必需的最小片段 毒性，以便进一步研究ALS的发病机制 提供便利。为了实现这一目标，我们建议开发更多的转基因 连续表达较小SOD1片段的小鼠系 确定引起肌萎缩侧索硬化症的SOD1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.