BRN-3 POU DOMAIN PROTEINS IN RETINAL DEVELOPMENT

BRN-3 POU 结构域蛋白在视网膜发育中的作用

• 批准号: 6383703
• 负责人: WILLIAM H. KLEIN
• 金额: $ 30万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6383703
• 关键词: cell differentiation; developmental neurobiology; embryo /fetus cell /tissue; fusion gene; gene expression; gene targeting; genetic regulatory element; genetically modified animals; laboratory mouse; neurogenesis; phenotype; protein structure function; reporter genes; retinal ganglion; transcription factor; transfection /expression vector

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.

描述（由申请人提供）：本项目的长期目标 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。视网膜神经节细胞是 对于正常视力至关重要，它们的丧失会导致严重的眼部疾病 人类。例如，眼内眼压升高会引发 神经节细胞凋亡增强，进而导致青光眼。尽管 然而，它们的重要性在于与视网膜相关的基因知识库 神经节细胞的形成和存活还处于初级阶段。在这个应用程序中， 实验建议重点关注 Brn-3b，一种 POU 结构域转录 视网膜神经节细胞中的因子。在小鼠中，brn-3b 基因属于 第一个在有丝分裂后祖细胞（神经节细胞）中激活的基因 分化开始。尽管 brn-3b 很早就被激活，但它并没有被激活。 神经节细胞的初始规范所必需的，但它是必不可少的 为了它们的正常分化和生存。具有定向删除的小鼠 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，标志着对神经节细胞命运的承诺，并且是 对于视网膜神经节细胞的生存至关重要。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。最后两个目标涉及转录特性 Brn-3b。具体目标将： (1) 检验以下假设：视网膜 神经节细胞形成后，它们会抑制其进一步产生。拟议的 实验将利用基因技术专门消融视网膜神经节细胞 靶向白喉毒素； (2) 识别顺式监管要素 brn-3b 转录控制区，在有丝分裂后激活 brn-3b 神经节细胞祖细胞。 brn-3b 内的顺式调控元件 转录控制区将使用 BAC 转基因鉴定 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。实验将采用 HSV 介导的基因 转移至培养的视网膜外植体中； (4)判断brn-3b是否可以 使祖细胞承担视网膜神经节细胞命运的功能。数学5 是视网膜神经节细胞形成所需的原神经 bHLH 基因。 Brn-3b 将在 math5 位点处错误表达以确定 brn-3b 是否为 在存在和不存在的情况下足以促进神经节细胞分化 数学5.