Gbx2 regulates the development of an atypical amacrine cell.

项目总结 哺乳动物视网膜内有100多种不同的神经元亚型。近期 研究已经在我们理解特定的神经元亚型如何 发育，连接到功能回路，并导致疾病。然而，标记和标记的遗传工具 操纵单个神经元群体只存在于一小部分视网膜神经元。使用 遗传学方法，我根据视网膜神经元的选择性识别出了一组单一的视网膜神经元 转录因子Gbx2的表达。这些细胞是无长突细胞(ACS)，有几个 有趣的特性。Gbx2+急性冠脉综合征不表达抑制性神经递质GABA或甘氨酸。 相反，Gbx2+ACS显示出与双极细胞的缝隙连接，这表明 这些AC的初级突触输出可能是通过电突触。我会分析一下 发展Gbx2+急性冠脉综合征以研究Gbx2在其细胞特性、形态和功能中的作用 连通性。在目标1中，使用Gbx2条件基因敲除鼠标，我将确定Gbx2如何 调节Gbx2+ACS的形态和电偶联。我还将确定具体的 Gbx2+急性冠脉综合征中介导电突触形成的连接蛋白。在目标2中，我将执行RNAseq 对照和Gbx2条件性基因敲除急性冠脉综合征的分析以揭示其分子图谱并进行鉴定 Gbx2的特定效应器。我还将测试Gbx2作为终极命运的假设 选择器通过调节赋予Gbx2+ACS独特基因的表达来实现 特点。我的初步数据表明，这在一定程度上是通过对Robo的调节来实现的 受体，引导视网膜内Gbx2+AC树突的适当分层。这项研究将 提供了以前的形态和分子特性的综合分析 未知的无长突细胞，并将阐明Gbx2如何调节 这些神经元。这项研究的结果将导致基因工具和目标的产生 对未来健康和疾病中视网膜发育的研究是有用的。

PROJECT SUMMARY There are more than 100 distinct neuronal subtypes within the mammalian retina. Recent studies have made significant progress in our understanding of how specific neuron subtypes develop, wire into functional circuits, and contribute to disease. However, genetic tools to label and manipulate single populations of neurons only exist for a small proportion of retinal neurons. Using a genetic approach, I have identified a single population of retinal neurons based on their selective expression of the transcription factor Gbx2. These cells are amacrine cells (ACs) and have several interesting properties. Gbx2+ ACs do not express the inhibitory neurotransmitters, GABA or Glycine. Rather, Gbx2+ ACs exhibit gap junction coupled connections to bipolar cells, suggesting that the primary synaptic output for these ACs may be through electrical synapses. I will analyze the development of Gbx2+ ACs to investigate the role of Gbx2 in their cellular identity, morphology, and connectivity. In Aim 1, using a Gbx2 conditional knockout mouse, I will determine how Gbx2 regulates the morphology and electrical coupling of Gbx2+ ACs. I will also identify the specific connexins that mediate electrical synapse formation in Gbx2+ ACs. In Aim 2, I will perform RNAseq analyses in control and Gbx2 conditional knockout ACs to reveal their molecular profile and identify the specific effectors of Gbx2. I will also test the hypothesis that Gbx2 functions as a terminal fate selector to by regulating the expression of genes that endow Gbx2+ ACs with their unique characteristics. My preliminary data indicate that this occurs in part through the regulation of Robo receptors, which guide the proper stratification of Gbx2+ AC dendrites within the retina. This study will provided a comprehensive analysis of the morphological and molecular properties of a previously unidentified amacrine cell, and will elucidate how Gbx2 regulates the development and function of these neurons. The results of this study will lead to the generation of genetic tools and targets that will be useful for future investigations of retina development in health and disease.