Molecular Studies of Retinal Degeneration in Drosophila

描述（由申请人提供）：我们的长期目标是揭示遗传性人类致盲疾病的分子遗传学，如视网膜色素变性（RP）和年龄相关性黄斑变性（AMD）。导致AMD和RP中光感受器细胞死亡的遗传缺陷是高度异质性的，现在包括超过132个基因的列表。AMD和RP复杂多样的临床和遗传学表现表明，这两种疾病存在多种亚型，每种亚型都有不同的遗传和生化基础。这种复杂性，RP和AMD患者眼部组织的罕见可用性，以及果蝇遗传学知识的广泛基础，都使果蝇成为研究遗传性视网膜变性疾病的强大动物模型。我们建议使用果蝇作为模型来识别和表征人类致盲疾病的新位点，为视网膜变性的分子基础提供机制见解。我们将使用遗传、生化、细胞生物学、电生理学和分子方法的综合策略来揭示光感受器细胞中协调蛋白质生物合成的各种分子信号机制。我们的研究重点是确保新合成蛋白质的正确折叠，修饰，寡聚物组装，质量控制，运输和靶向的那些事件。这些过程中的缺陷经常刺激广泛的细胞反应，导致发病，在严重的情况下，神经退行性变。在这里，我们将描述分子伴侣calnexin，以及在calnexin通路中起作用的4个新位点：cip1， cip2， cip3和cip4。钙连蛋白是一种分子伴侣，促进内质网新生糖蛋白的适当折叠。在离开内质网后，新折叠的蛋白质必须被运送到高尔基体，在那里它们经历一系列新的修饰。蛋白在两个腔室之间的运输是通过囊泡的出芽和融合发生的。我们将描述高尔基体中囊泡融合事件所需的一种新型光感受器SNARE蛋白。我们已经证明，钙连联蛋白、cip1-4和snare基因的突变会导致视紫红质表达缺陷并导致视网膜变性。我们的发现将用于筛选人类AMD和RP谱系相似的突变。我们的目标是发现致盲疾病的新位点，为视网膜变性的分子机制提供见解，并为RP和AMD的治疗提供治疗方法。

DESCRIPTION (provided by applicant): Our long-term objective is to unravel the molecular genetics of hereditary human blinding diseases, such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Genetic defects that lead to photoreceptor cell death in AMD and RP are highly heterogeneous and now include a list of more than 132 genes. The complex and various clinical and genetic findings in AMD and RP suggest that there are multiple subtypes of the diseases, each with a distinct genetic and biochemical basis. This complexity, the infrequent availability of ocular tissues from RP and AMD patients, and the broad base of knowledge of Drosophila genetics, all combine to make Drosophila a powerful animal model for studying inherited retinal degeneration disorders. We propose to use Drosophila as a model to identify and characterize novel loci in human blinding diseases, providing mechanistic insights into the molecular basis of retinal degeneration. We will use an integrated strategy of genetic, biochemical, cell biological, electrophysiological, and molecular approaches to uncover the diverse molecular signaling mechanisms that coordinate protein biosynthesis in photoreceptor cells. Our research focuses on those events that ensure correct folding, modification, oligomeric assembly, quality control, trafficking and targeting of newly synthesized proteins. Defects in these processes often stimulate extensive cellular responses that lead to pathogenesis and, in severe cases, neurodegeneration. Here, we will characterize the molecular chaperone calnexin, and 4 novel loci that function in the calnexin pathway: cip1, cip2, cip3 and cip4. Calnexin is a molecular chaperone that promotes the proper folding of nascent glycoproteins in the endoplasmic reticulum (ER). Upon exiting the ER, newly folded proteins must be transported to the Golgi where they undergo a new set of modifications. Transport of proteins between the two compartments occurs via the budding and fusion of vesicles. We will characterize a novel photoreceptor SNARE protein required for vesicular fusion events in the Golgi. We have shown that mutations in calnexin, cip1-4 and the snare gene cause defects in rhodopsin expression and lead to retinal degeneration. Our findings will be used to screen human AMD and RP pedigrees for similar mutations. We aim to uncover novel loci in blinding diseases, provide insights into the molecular mechanisms of retinal degeneration, and offer therapeutic approaches for treating RP and AMD.