Mouse Model of DBC Dysfunction

描述（由申请人提供）：先天性静止性夜盲（CSNB）是损害视杆细胞介导视力的非进行性视网膜疾病的临床术语。CSNB的完整形式（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。由于所有的视觉输入都是通过双极细胞从视网膜的外层传递到内层的，因此了解DBCs中的信号转导机制至关重要。最近的工作已经确定了几个，但不是所有的，在这一级联的球员。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基因位点与所有其他已知的DBC功能障碍模型不同，因此其鉴定将为已知对DBC功能至关重要的蛋白质添加另一种蛋白质。这些研究将使用下一代测序和定位克隆来定位和克隆负责nob5表型的基因。在目标2中，我们将定义nob5表型与视网膜功能，使用视网膜电图和全细胞膜片钳记录从杆和锥DBCs和锥超极化双极细胞，和光感受器和DBCs之间的突触形态，使用共聚焦显微镜和免疫组织化学。在该项目完成时，我们将确定一种新的蛋白质，该蛋白质是正常DBC功能所需的，可用于筛查cCSNB患者。 公共卫生相关性：本项目将对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，并将为人类先天性静止性夜盲症的完整形式确定一个潜在的新候选基因。

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.