Cellular and Molecular Mechanisms Regulating Photoreceptor Morphology

描述（由申请人提供）：光感受器是对光作出反应并将其转化为化学信号的主要细胞，是受光感受器变性疾病影响的细胞，包括黄斑变性、色素性视网膜炎（RP）和其他遗传性视网膜变性。尽管许多基因突变已被确定与光感受器变性疾病相关，但我们仍然对这些突变导致光感受器死亡的原因知之甚少。这一建议旨在扩大我们对脊椎动物光感受器如何获得和维持其独特的功能形态以及光感受器形态与生存之间关系的理解。我们已经证明FERM结构域包含的蛋白质马赛克眼（Moe）是面包屑蛋白功能的重要调节因子，直接与面包屑蛋白相互作用，也表明缺乏Moe功能的杆状光感受器具有比正常更大的外段。据我所知，这是第一个基因功能丧失的例子，导致一个比正常外段更大的外段，而不是更小的外段。人类面包屑同源基因1 （CRB1）的突变与两种视力丧失疾病——利伯氏先天性黑内障和视网膜色素变性12有关。这些疾病的严重程度和早发性表明，CRB1功能对光感受器发育的早期阶段至关重要，并表明了解CRB1和相关蛋白在光感受器中的作用可能会为我们提供治疗LCA和RP12的方法。缺乏Crb1功能的小鼠的光感受器比正常的内、外段短。确定碎屑蛋白在光感受器中的功能也可以进一步了解光感受器发育的早期阶段。为了进一步了解光感受器形态发生的细胞和分子机制，我们提出了三个具体目标：(1)研究Crb2a在调节光感受器和Muller胶质细胞形态中的作用。(2)研究Prkci在调节面包屑蛋白功能、光感受器和Muller胶质细胞形态中的作用。(3)研究与Moe/ epb4115相互作用的蛋白rhiphhilin 1 （Rhpn1）在调节crumb蛋白功能中的作用。我们研究的另一个长期目标是生成工具来测试内外节段大小和光感受器变性之间的因果关系，因为在光感受器变性之前经常观察到内外节段的缩短。

DESCRIPTION (provided by applicant): Photoreceptors are the primary cells that respond to light and transduce it into a chemical signal and are the cells affected in photoreceptor degeneration diseases, including macular degeneration, retinitis pigmentosa (RP) and other inherited retinal degenerations. Although mutations in many genes have been identified that are associated with photoreceptor degeneration diseases, we still know very little about why these mutations cause photoreceptors to die. This proposal seeks to expand our understanding of how vertebrate photoreceptors attain and maintain their unique functional morphology and relationship between photoreceptor morphology and survival. We have shown that the FERM domain containing protein Mosaic eyes (Moe) is an important regulator of Crumbs protein function, directly interacts with Crumbs proteins and also showed that rod photoreceptors that lack moe function have outer segments that are larger than normal. To my knowledge this is the first example of loss-of-function of a gene that results in a larger than normal outer segment instead of a smaller one. Mutations in the human CRUMBS HOMOLOGUE 1 (CRB1) are associated with two vision-loss diseases, Leber's congenital amaurosis and retinitis pigmentosa 12. The severity and early onset of these diseases suggest that CRB1 function is critical for early stages of photoreceptor development and suggest that understanding the role of CRB1 and related proteins in photoreceptors may give us insight into ways to treat LCA and RP12. Photoreceptors in mice lacking Crb1 function have shorter than normal inner and outer segments. Determining the function of the Crumbs proteins in photoreceptors may also provide further insight into the early stages of photoreceptor development. To further our understanding of the cellular and molecular mechanisms that underlie photoreceptor morphogenesis we propose three specific aims: (1) Examine the role of Crb2a in regulating photoreceptor and Muller glial morphology. (2) Examine the role of Prkci in regulating Crumbs protein function and photoreceptor and Muller glial morphology. (3) Examine the role of Rhophilin 1 (Rhpn1), a protein that interacts with Moe/Epb41l5, in regulating Crumbs protein function. An additional long-term goal of our studies is to generate tools to test the causal relationship between outer and inner segment size and photoreceptor degeneration because a shortening of inner and outer segments is often observed prior to photoreceptor degeneration. PUBLIC HEALTH RELEVANCE: This proposal seeks to expand our understanding of how vertebrate photoreceptors attain and maintain their unique functional morphology. Photoreceptor degeneration is the cause of most forms of vision loss and yet we understand very little about why or how these cells die. Our research is aimed towards prolonging the survival and function of photoreceptors during disease processes.