PRESENILIN GENE STUDY IN DROSOPHILA MELANOGASTER AS MODEL

对早发性家族性阿尔茨海默病（AD）家族的遗传连锁研究已经确定，至少三个位点的突变会导致该疾病：淀粉样蛋白前体基因、早老素-1基因（PS-1）和早老素-2基因（PS-2）。虽然有报道称，携带PS-1和PS-2突变家族的成纤维细胞中β -淀粉样蛋白产生异常，并且秀丽隐杆线虫中的同源蛋白影响Notch信号传导，但早老素基因的功能目前尚不清楚。因此，这项应用的长期目标是确定早老素蛋白和其他早老素相互作用蛋白的功能。黑腹果蝇是确定非特征基因功能的理想模式生物，在这种情况下，由于大多数Notch信号的研究都是在果蝇中进行的，因此更加理想。利用早老素基因之间的高度保守性，我们实验室成功地在果蝇中克隆了该基因。该项目的第一个具体目标将是在果蝇中表征该基因，研究其基因结构，发育转录模式，及其在胚胎，幼虫，蛹和成虫中的定位，DNA测序。南方和北方印迹技术，以及光学显微镜将用于执行这部分项目。第二个具体目标将是产生该基因的零突变并研究其在果蝇中的作用。利用p -元件插入诱变技术制备突变体果蝇，并对其进行遗传鉴定。第三个具体目标将是确定哪些基因与早老素基因相互作用。蝇遗传学和酵母双杂交方法将被用来寻找这些蛋白前相互作用的基因。这个项目将导致对早老素基因的生物学和功能有更深入的了解，早老素基因是早发性家族性阿尔茨海默病的主要原因。通过确定早老素的功能及其与其他基因的相互作用，我们将对阿尔茨海默病的发病机制有更深入的了解，这可能最终导致改善该病的治疗。此外，对这些早老素相互作用蛋白的长期研究将有助于我们确定其他可能导致或影响早发性和晚发性AD的人类基因座。

Genetic linkage studies in early onset-familial Alzheimer's disease (AD) families have determined that mutations in at least three loci will cause the disease: the amyloid beta-protein precursor gene, the presenilin-1 gene (PS-1), and the presenilin-2 gene (PS-2). While it has been reported that beta-amyloid production is abnormal in fibroblasts from families carrying PS-1 and PS-2 mutations, and a homologues protein in C. elegans affects Notch signaling, the function of the presenilin gene is presently unknown. Therefore, the long-term objective of this application is to determine the function of the presenilin protein and other presenilin- interacting proteins. Drosophila melanogaster is an ideal model organism for determining the function of uncharacterized genes, which in this case is made even more ideal as most studies of Notch signaling have been carried out in Drosophila. Using the high conservation among conservation among presenilin genes, our lab has successfully coned the gene in Drosophila. The first specific aim of this project will be to characterize this gene in Drosophila, studying its gene structure, its developmental transcription pattern, and its localization in embryos, larvae, pupae, and adult flies, DNA sequencing. Southern and Northern blotting techniques, and light microscopy will be used to carry out this part of the project. The second specific aim will be to produce null mutations of this gene and study their effects in Drosophila. P-element insertion mutagenesis will be used to produce the mutant flies, and the flies will be characterized genetically. The third specific aim will be to determine which genes interact with the presenilin gene. Fly genetics and yeast two-hybrid approaches will be used to find these presinilin- interacting genes. This project will lead to a greater understanding about the biology and function of the presenilin genes, the major cause of early- onset familial Alzheimer's disease. By determining the functions of the presenilins, and their interactions with other genes, a greater understanding of the pathogenesis of AD will be gained, which may lead eventually to improved treatment of the disease. Additionally, a long- term study of these presenilin-interacting proteins will help us to identify other human loci which may cause or influence AD in both early-onset and late-onset cases.