Gbx2 regulates the development of an atypical amacrine cell.

项目摘要 在哺乳动物视网膜内有超过100种不同的神经元亚型。最近 研究已经在我们理解特定神经元亚型 发展、连接到功能电路中并导致疾病。然而，基因工具来标记和 操纵单个神经元群体仅存在于一小部分视网膜神经元中。使用 通过遗传学方法，我已经确定了一个单一的视网膜神经元群体，基于他们的选择性， 转录因子Gbx2的表达。这些细胞是无长突细胞（AC），并且具有几个 有趣的属性。Gbx2+ AC不表达抑制性神经递质GABA或甘氨酸。 相反，Gbx2+ AC表现出与双极电池的间隙结耦合连接，这表明 这些AC的主要突触输出可以通过电突触。我将分析 Gbx2+ AC的开发，以研究Gbx2在其细胞身份、形态和功能中的作用。 连通性。在目标1中，使用Gbx2条件性敲除小鼠，我将确定Gbx2 调节Gbx2+ AC的形态和电耦合。我还将确定具体 在Gbx2+ AC中介导电突触形成的连接蛋白。在目标2中，我将执行RNAseq 在对照和Gbx2条件性敲除AC中进行分析，以揭示其分子谱并鉴定 Gbx2的特定效应器。我还将检验Gbx2作为终端命运的假设， 通过调节基因的表达，使Gbx2+ AC具有独特的 特色我的初步数据表明，这部分是通过调节机器人来实现的。 受体，其引导视网膜内Gbx2+ AC树突的适当分层。本研究将 提供了一个全面的分析形态和分子特性的先前 未鉴定的无长突细胞，并将阐明Gbx2如何调节的发展和功能， 这些神经元。这项研究的结果将导致遗传工具和目标的产生， 对未来健康和疾病中视网膜发育的研究有用。

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.