Molecular Studies of Retinal Degeneration in Drosophila

描述(申请人提供)：我们的长期目标是了解遗传性人类视网膜疾病的分子遗传学，如视网膜色素变性(RP)和年龄相关性黄斑变性(AMD)。我们的方法是使用果蝇作为模型系统。人类RP和AMD是高度复杂的疾病，有多个亚型，每个亚型都有不同的遗传和生化基础。这种复杂性，加上来自RP和AMD患者的合适组织的有限可获得性，以及对果蝇遗传学的广泛知识基础，使果蝇成为研究遗传性视网膜变性疾病的强大动物模型。我们的研究集中在分泌途径中蛋白质生物合成过程中的那些事件，以确保正确的蛋白质转位、糖基化、折叠、寡聚组装、质量控制、运输和靶向。内质网(ER)含有多种分子伴侣、折叠感应器和酶，以及促进蛋白质生物合成早期阶段的护航蛋白质。一旦离开内质网，新折叠的蛋白质必须被运输到高尔基体，在那里它们经历了一系列新的修饰，这些修饰依次从顺式到内侧-，最后到高尔基体的跨隔室。蛋白质在分泌途径的不同隔间之间的运输是通过小泡的萌发和融合从供体隔间到靶向隔间进行的。囊泡的转运受到大量的细胞液和膜结合因子的促进，如GTP结合蛋白(RAB)、外壳成分、马达蛋白、拴系分子，最后是SNARES(可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体)。在这一应用中，我们特别关注蛋白质生物合成和运输的两个主要方面：(1)SNARE蛋白及其在视紫红质和其他光转导成分的囊泡运输中的作用；(2)甘露糖苷酶家族及其在视紫红质生物合成过程中削减内质网和高尔基体中碳水化合物的关键作用。鉴于这里研究的SNARE蛋白和甘露糖苷酶在人类中高度保守，我们在果蝇中的发现应该很容易应用于人类过程和疾病。因此，我们在果蝇中的发现将被用于筛选一组高度明确的人类AMD和RP家系，以寻找类似的缺陷。我们预计，这项工作将极大地影响我们对蛋白质运输的基本机制的理解，并为视网膜疾病，如RP和AMD提供重要的见解。

DESCRIPTION (provided by applicant): Our long-term objective is to understand the molecular genetics of hereditary human retinal diseases, such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Our approach is to use Drosophila as a model system. Human RP and AMD are highly complex diseases with multiple subtypes, each with a distinct genetic and biochemical basis. This complexity, along with the limited availability of suitable tissues from RP and AMD patients and the broad base of knowledge of Drosophila genetics, combine to make Drosophila a powerful animal model for studying inherited retinal degeneration disorders. Our research is focused on those events during protein biosynthesis in the secretory pathway that ensure correct protein translocation, glycosylation, folding, oligomeric assembly, quality control, transport and targeting. The endoplasmic reticulum (ER) contains a wide variety of molecular chaperones, folding sensors and enzymes, as well as escort proteins that facilitate the early stages of protein biosynthesis. Upon exiting the ER, newly folded proteins must be transported to the Golgi, where they undergo a new set of modifications that proceed sequentially from the cis- to the medial-, and finally to the trans- compartments of the Golgi. Transport of proteins between compartments of the secretory pathway occurs via the budding and fusion of small vesicles from donor compartments to target compartments. Vesicular transport is facilitated by a vast array of cytosolic and membrane bound factors, such as GTP-binding proteins (Rabs), coat components, motor proteins, tethering molecules, and finally SNAREs (soluble N- ethylmaleimide-sensitive factor attachment protein receptor). In this application we are specifically focused on two major aspects of protein biosynthesis and transport: (1) The SNARE proteins and their role in vesicular transport of rhodopsin and other constituents of phototransduction, and (2) the family of mannosidases and their key roles in trimming carbohydrates in the ER and Golgi during rhodopsin biosynthesis. Given that the SNARE proteins and mannosidase enzymes investigated here are highly conserved in humans, our findings in Drosophila should be readily applied to human processes and diseases. Accordingly, our discoveries in Drosophila will be used to screen a highly defined set of human AMD and RP pedigrees for similar defects. We anticipate that this work will greatly impact our understanding of the fundamental mechanisms of protein trafficking and also provide important insights into retinal diseases such as RP and AMD.