Genetic Modifiers of Enhanced S-cone Syndrome –Role of the External Limiting Membrane

项目总结/摘要 增强型S-视锥综合征（ESCS）是一种遗传性视网膜变性，其特征在于S-视锥细胞增殖增加。 S-视锥细胞数量、视网膜发育不良和进行性感光细胞变性导致早睡 失明和视力丧失。这种疾病是由杆状病毒命运决定基因突变引起的。 转录因子NR 2 E3在人类和rd 7小鼠模型中的表达。疾病的表现是高度可变的， 人类和依赖于小鼠的遗传背景，证明存在遗传修饰剂。 小鼠模型表明视网膜发育不良与视网膜病变的发生密切相关。 外界膜（ELM）断裂，Müller细胞之间的粘附/紧密连接网络 顶端突起和感光器内节。在其他国家也观察到ELM的碎片化。 与发育不良相关的视网膜疾病，例如由于Leber's先天性黑蒙（LCA）， crumbs 1（CRB 1）和RP 27，以及糖尿病视网膜病变。 我们已经确定了一种遗传修饰剂，可以防止rd 7小鼠和小鼠中ELM的片段化。 和Nr 1 ko小鼠（RP 27）模型。这一发现有力地表明了ELM的致病作用 碎片的发展感光细胞发育不良，并提供了一个工具，以建立 ELM断裂发生的机制，它们如何导致视网膜发育不良，以及这如何影响疾病 进展 为了确定这些机制，我们将：1）确定ELM结的自然历史 使用细胞连接的标记物分析的WT和RD 7模型中的光感受器形成和分化 proteins. 2)通过单细胞RNAseq分析鉴定参与ELM片段化的细胞类型。第三章 确定修饰蛋白如何改变连接蛋白向细胞膜的募集。4)识别 我们已经产生了额外的遗传修饰菌株的分子基础，以进一步了解 NR 2 E3疾病通路。

PROJECT SUMMARY/ABSTRACT Enhanced S-cone syndrome (ESCS) is an inherited retinal degeneration characterized by an increased number of S-cones, retinal dysplasia, and progressive photoreceptor degeneration leading to early night blindness and loss of visual acuity. The disease is caused by mutations in the rod-fate determining transcription factor NR2E3 in humans and the rd7 mouse model. The disease presentation is highly variable in human and dependent on genetic background in the mouse, demonstrating the existence of genetic modifiers. The mouse model demonstrates that the retinal dysplasia is intimately associated with the occurrence of breaks in the external limiting membrane (ELM), a network of adherens/tight junctions between Müller cell apical processes and photoreceptor inner segments. Fragmentation of the ELM is also observed in other retinal diseases associated with dysplasia, such as Leber's Congenital Amaurosis (LCA) due to mutations in crumbs1 (CRB1) and RP27, and in diabetic retinopathy. We have identified a genetic modifier that prevents the fragmentation of the ELM in both the rd7 mouse and the Nrl ko mouse (RP27) models. This discovery strongly suggests a causative role for the ELM fragmentation in the development of photoreceptor dysplasia and provides a tool with which to establish the mechanisms by which ELM breaks occur, how they lead to retinal dysplasia, and how this affects disease progression. In order to identify these mechanisms we will: 1) Determine the natural history of ELM junction formation and photoreceptor differentiation in wt and the rd7 model using marker analysis of cell junction proteins. 2) Identify the cell types involved in the ELM fragmentation by single cell RNAseq analysis. 3) Determine how the modifier protein alters recruitment of junctional proteins to the cell membrane. 4) Identify the molecular basis of additional genetic modifier strains that we have generated to gain further insight into the NR2E3 disease pathways.