Mouse Model of DBC Dysfunction

描述(申请人提供)：先天性静止性夜盲(CSNB)是损害视杆介导的视力的非进行性视网膜疾病的临床术语。完整形式的CSNB(CCSNB)是由去极化双极细胞(DBC)信号转导缺陷引起的，在患者中与NYX、GRM6或TRPM1突变有关。由于所有视觉输入的流动是通过双极细胞从视网膜的外部传递到内部的，因此了解DBCS的信号转导机制是至关重要的。最近的研究确定了这一级联中的几个参与者，但不是所有参与者。在这个项目中，我们将确定另一个关键蛋白质。在目标1中，我们将确定一种新的DBC功能障碍小鼠模型nob5的基因和突变。Nob5基因座不同于所有其他已知的DBC功能障碍模型，因此它的发现将为那些已知的DBC功能关键蛋白增加另一种蛋白质。这些研究将使用下一代测序和位置克隆来定位和克隆与nob5表型有关的基因。在目标2中，我们将通过视网膜电图术和视杆细胞、视锥细胞和视锥细胞超极化双极细胞的全细胞膜片钳记录，以及利用共聚焦显微镜和免疫组织化学观察光感受器和视锥细胞之间突触的形态，来确定与视网膜功能有关的nob5表型。在这个项目完成后，我们将识别出一种新的蛋白质，它是正常DBC功能所必需的，可以用于筛查cCSNB患者。 与公共卫生相关：该项目将对一种缺乏去极化双极细胞(DBC)功能的新小鼠模型(Nob5)进行详细研究。Nob5基因尚未被鉴定，但已知涉及一种以前未涉及DBC功能的蛋白质。Nob5基因的鉴定将扩大我们对DBC信号转导的理解，并将发现一个潜在的新的候选基因，用于治疗完全性人类先天性静止性夜盲。

DESCRIPTION (provided by applicant): Congenital stationary night blindness (CSNB) is the clinical term for non-progressive retinal disorders that impair rod-mediated vision. The complete form of CSNB (cCSNB) is caused by defects in depolarizing bipolar cell (DBC) signal transduction and in patients has been linked to mutations in NYX, GRM6 or TRPM1. Because the flow of all visual input is transferred from the outer to the inner retina via bipolar cells, it is critical to understand the mechanism of signal transduction in DBCs. Recent work has defined several, but not all, players in this cascade. In this project, we will identify another key protein. In Aim 1, we will identify the gene and mutation that underlies a new mouse model of DBC dysfunction, nob5. The nob5 gene locus is distinct from all other known models of DBC dysfunction and therefore its identification will add another protein to those known to be critical for DBC function. These studies will use next generation sequencing and positional cloning to map and clone the gene responsible for the nob5 phenotype. In Aim 2, we will define the nob5 phenotype with respect to retinal function, using electroretinography and whole-cell patch clamp recordings from rod and cone DBCs and cone hyperpolarizing bipolar cells, and the morphology of the synapses between photoreceptors and DBCs, using confocal microscopy and immunohistochemistry. At the completion of this project, we will have identified a new protein that is required for normal DBC function and which can be used to screen patients with cCSNB. PUBLIC HEALTH RELEVANCE: This project will make detailed studies of a new mouse model (nob5) that lacks depolarizing bipolar cell (DBC) function. The nob5 gene has not been identified, but is known to involve a protein that has not been previously implicated in DBC function. Identification of the nob5 gene will expand our understanding of DBC signal transduction and will identify a potential new candidate gene for the complete form of human congenital stationary night blindness.