TRANSGENIC C ELEGANS AS AMYLOID DISEASE MODEL

本项目的目标是了解β -淀粉样肽（Abeta）毒性的细胞和分子基础。这种肽以不溶性淀粉样蛋白聚集体的形式沉积在阿尔茨海默病（AD）患者大脑中的老年斑中，被认为是该疾病病理的核心。一种新的AD模型系统将被采用，在该系统中，一种被广泛研究的线虫，秀丽隐杆线虫，被改造成表达人类β肽。这些转基因动物表达高水平的β肽，这迅速导致淀粉样蛋白沉积的形成和相关的毒性作用。该模型系统将用于通过构建表达含有单个或多个氨基酸取代的野生型和变体Abeta的转基因动物来研究Abeta结构、聚集和毒性之间的关系。这些动物将被检测淀粉样蛋白的形成和已知的β毒性标记，如对蛋白质的氧化损伤。这些动物的特征还将包括完整的β依赖基因表达谱的检查，通过mRNA杂交到含有绝大多数秀丽隐杆线虫基因探针的DNA微阵列进行检测。这种模式生物的遗传可及性也将允许通过分离和表征抑制Abeta肽毒性作用的突变来识别与Abeta毒性直接相关的基因。

The goal of this project is to understand the cellular and molecular basis of beta-amyloid peptide (Abeta) toxicity. This peptide is deposited as insoluble amyloid aggregates in the senile plaques found in the brains of Alzheimer's Disease (AD) patients, and is believed to be central to the pathology of this disease. A novel AD model system will be employed in which of the intensely studied nematode worm, Caenorhabditis elegans, is engineered to express human Abeta peptide. These transgenic animals express high levels of the Abeta peptide, which rapidly leads to the formation of amyloid deposits and associated toxic effects. This model system will be used to investigate the relationships between Abeta structure, aggregation, and toxicity by the construction of transgenic animals expressing wild-type and variant Abeta containing single or multiple amino acid substitutions. These animals will be assayed for amyloid formation and known markers of Abeta toxicity, such as oxidative damage to proteins. Characterization of these animals will also include examination of the complete Abeta-dependent gene expression profile, assayed by mRNA hybridization to DNA microarrays that contain probes for the vast majority of C. elegans genes. The genetic accessibility of this model organism will also allow the identification of genes directly involved in Abeta toxicity, by the isolation and characterization of mutations that suppress the toxic effects of the Abeta peptide.