The Role of TULP1 in Photoreceptor Cells

描述（由申请人提供）：TULP 1是我们鉴定的导致常染色体隐性视网膜色素变性的基因，这是一种遗传性视网膜变性，全球近100万人致盲。RP的遗传病因是已知的约50%的情况下，然而，参与引起疾病的生化途径要少得多，拟议的研究的总体目标是探索的生理功能的TULP 1在视网膜和定义的病理机制，导致感光细胞变性与TULP 1突变。TULP家族由四种功能未知的蛋白质组成，其中两种与感光细胞变性有关。 本申请的两个具体目的旨在测试中心假设，即TULP 1是参与感光细胞中蛋白质定向易位的分子机制的组成部分。第一个具体目标是确定TULP 1在光感受器转运途径中的作用。这将通过使用免疫细胞化学来确定是否外节蛋白，细胞内转运蛋白和突触蛋白在tulp 1-/-视网膜中是错误的。将进行免疫电子显微镜检查，以确定不正确转运的蛋白质是否是tulp 1-/-视网膜细胞外囊泡上的货物。第二个具体目标是确定在感光细胞中鉴定的TULP 1/发动蛋白-1相互作用的功能。这将通过鉴定TULP 1和发动蛋白-1之间相互作用的功能结构域并确定引起RP的TULP 1突变是否改变两种蛋白质之间的结合来完成。还提出了使用Cre-loxP诱变产生感光细胞中缺乏发动蛋白-1的小鼠并使其表型化的实验。如目的1所述，将在这些小鼠中评价转运途径。 由于对TULP蛋白知之甚少，发现有关TULP蛋白功能的信息应提供有关感光细胞变性途径的知识。这项工作可能为未来的研究奠定基础，旨在评估可能减缓、停止或逆转视网膜变性过程的治疗方式。

DESCRIPTION (provided by applicant): TULP1 is a gene we identified to cause autosomal recessive retinitis pigmentosa, a hereditary retinal degeneration blinding nearly 1 million people worldwide. The genetic etiology of RP is known for about 50% of cases; however, the biochemical pathways involved in causing the disease much less. The overall objectives of the proposed studies are to explore the physiologic function of TULP1 in the retina and to define the pathologic mechanism leading to photoreceptor degeneration associated with TULP1 mutations. The TULP family consists of four proteins of unknown function, two of which are linked to photoreceptor degeneration. The two specific aims of this application are designed to test the central hypothesis that TULP1 is a component of the molecular machinery involved in the directional translocation of proteins in photoreceptor cells. The first specific aim is to determine the role of TULP1 in photoreceptor transport pathways. This will be accomplished by using immunocytochemistry to determine whether outer segment proteins, intracellular transport proteins and synaptic proteins are mistargeted in tulp1-/- retinas. Immunoelectron microscopy will be performed to determine if the proteins that are incorrectly transported are cargo on the extracellular vesicles in tulp1-/- retinas. The second specific aim is to determine the function of the TULP1/Dynamin-1 interaction identified in photoreceptor cells. This will be done by identifying the functional domains that interact between TULP1 and Dynamin-1 and determining whether TULP1 mutations that cause RP alter the binding between the two proteins. Experiments are also proposed to generate and phenotype mice lacking Dynamin-1 in photoreceptor cells using Cre-loxP mutagenesis. Transport pathways will be evaluated in these mice as described in aim 1. Since little is known about TULP proteins, discovering information regarding the function of TULP proteins should provide knowledge about the pathways involved in photoreceptor degeneration. It is possible that this work could form the foundation for future studies aimed at evaluating therapeutic modalities that might slow, stop, or reverse the course of retinal degeneration.