BRN-3 POU DOMAIN PROTEINS IN RETINAL DEVELOPMENT

描述(由申请人提供)：这项计划的长期目标 应用程序是为了深入了解导致 哺乳动物视网膜神经节细胞的分化。视网膜神经节细胞 对正常视力是必不可少的，而它们的丧失是导致中国主要眼病的原因 人类。例如，眼内眼压升高可能会引发 神经节细胞凋亡增强，进而导致青光眼。尽管 然而，它们的重要性是与视网膜相关的基因的知识库 神经节细胞的形成和存活是基本的。在此应用程序中， 针对BRN-3b，一个POU结构域的转录，提出了实验方案 视网膜神经节细胞中的因子。在小鼠中，BRN-3b基因是 第一批在有丝分裂后祖细胞中被激活的基因作为神经节细胞 分化开始了。尽管有这种早期激活，但BRN-3b并不是 神经节细胞的初始规格所必需的，但它是必不可少的 为了它们的正常分化和生存。靶向缺失的小鼠 BRN-3b的视网膜有缺陷，大部分神经节细胞丢失。因此，BRN-3b 是一个关键基因，标志着神经节细胞命运的承诺，并且 对视网膜神经节细胞的生存至关重要。的前两个目标 该应用程序使用BRN-3b基因座来探测视网膜神经节的早期事件 细胞形成。最后两个目标与转录特性有关 BRN-3b。具体目标将：(1)检验作为视网膜的假设 神经节细胞形成时，它们会抑制它们的进一步产生。建议数 实验将利用基因技术特定地去除视网膜神经节细胞 靶向白喉毒素；(2)确定顺式调控元件在 在有丝分裂后激活BRN-3b的转录控制区 神经节细胞的祖细胞。BRN-3b中的顺式监管要素 将使用BAC转基因来鉴定转录控制区 分析；(3)研究BRN-3b在视网膜中的功能特异性 神经节细胞分化。这些实验将使用HSV介导的基因 转移到培养的视网膜组织中；(4)确定BRN-3b能否 在将祖细胞转化为视网膜神经节细胞命运的过程中发挥作用。数学5 是视网膜神经节细胞形成所必需的神经性bHLH基因。BRN-3b 将在math5位点错误表达以确定BRN-3b是否 足以在有无时促进神经节细胞分化 数学5。

DESCRIPTION (provided by applicant): The long-term objective of this application is to gain insights into the molecular events that lead to the differentiation of mammalian retinal ganglion cells. Retinal ganglion cells are essential for normal vision and their loss contributes to major eye diseases in humans. For example, elevated intraocular pressure within the eye can trigger enhanced apoptosis in ganglion cells, which in turn leads to glaucoma. Despite their importance, however, the knowledge base of genes associated with retinal ganglion cell formation and survival is rudimentary. In this application, experiments are proposed that focus on Brn-3b, a POU-domain transcription factor, in retinal ganglion cells. In the mouse, the brn-3b gene is among the first genes activated in postmitotic progenitor cells as ganglion cell differentiation begins. In spite of this early activation, brn-3b is not required for the initial specification of ganglion cells, but it is essential for their normal differentiation and survival. Mice with targeted deletions in brn-3b have defective retinas with a loss of most ganglion cells. Thus, brn-3b is a critical gene that marks the commitment to a ganglion cell fate and is essential for the survival of retinal ganglion cells. The first two aims of this application use the brn-3b locus to probe early events of retinal ganglion cell formation. The final two aims concern the transcriptional properties of Brn-3b. The Specific Aims will: (1) Test the hypothesis that as retinal ganglion cells form, they inhibit their further production. The proposed experiments will specifically ablate retinal ganglion cells using genetically targeted diphtheria toxin; (2) Identify the cis-regulatory elements within the brn-3b transcriptional control region that activate brn-3b in postmitotic ganglion cell progenitors. The cis-regulatory elements within the brn-3b transcriptional control region will be identified using BAC transgenic analysis; (3) Investigate the functional specificity of Brn-3b in retinal ganglion cell differentiation. The experiments will employ HSV-mediated gene transfer into cultured retinal explants; (4) Determine whether brn-3b can function in committing progenitor cells to a retinal ganglion cell fate. Math5 is a proneural bHLH gene required for retinal ganglion cell formation. Brn-3b will be misexpressed at the math5 locus to determine whether brn-3b is sufficient to promote ganglion cell differentiation in the presence and absence of math5.