MOLECULAR STUDIES OF RETINAL DEVELOPMENT

视网膜发育的分子研究

• 批准号: 2634431
• 负责人: Iqbal Ahmad
• 金额: $ 11.52万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-01-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2634431
• 关键词: DNA binding protein; cell differentiation; cell type; gel mobility shift assay; gene expression; gene mutation; genetic regulatory element; growth factor; histogenesis; immunocytochemistry; immunoprecipitation; in situ hybridization; laboratory mouse; laboratory rat; molecular cloning; monoclonal antibody; neurogenesis; neurogenetics; polymerase chain reaction; regulatory gene; retina; retinal bipolar neuron; retinal pigment epithelium; site directed mutagenesis; transcription factor; western blottings

The acquisition of neuronal diversity is central to the development and organization of the mammalian central nervous system (CNS). Our understanding of some of the mechanisms by which this diversity is achieved has been greatly facilitated by studies of neuronal differentiation in retina, a well characterized model of the CNS. Lineage analyses of neuronal precursors in vivo using retroviral infections and progressive lineage restriction during cell-type specification. However, our understanding of the molecular basis of these processes remains unclear for the lack of information regarding genes involved in the mammalian neurogenesis. One of the approaches is to identify and study the retina-specific expression of the mammalian homologs of Drosophila genes whose role in neurogenesis has been well established by mutation analyses. Depending upon their spatio-temporal expression and functions during early neurogenesis these genes belong to two different classes, the proneural genes of the achaete-scute (AS-C) complex that encode transcription factors of basic Helix-Loop-Helix (bHLH) class and the neurogenic genes of which Notch is a member, that encodes a membrane protein. Members of both proneural and neurogenic genes have been shown to play important roles in the development of Drosophila eye. The function of these genes in early neurogenesis in general and in the development of the eye in particular make their mammalian homologues ideal candidates for the investigation of the spatio-temporal expression of the mammalian homologs of AS-C and Notch genes in developing retina in order to know their cell-specific expression and to formulate a hypothesis regarding their function. Both genes may be involved in mediating intercellular interactions during retinal neurogenesis and cell-type specification. While AS-C homologs can activate the differentiation program by influencing the genome, Notch on the other had can link the activation f the genome with microenvironment in which the differentiation is taking place. In order to evaluate such possibilities, the expression of these genes will be studied in vitro in response to various growth factors that have been shown to modulate cell proliferation and differentiation in retina. The AS-C homologs, analogous to myogenic gene, MyoD may function as master regulatory genes involved in the activation of downstream neuron-specific genes in precursors during the early stages of neurogenesis. This hypothesis will lbs initially tested by analyzing the ability of AS-C homologs expressed in developing retina to interact with putative cis- acting elements (E-box) and evaluating their transcriptional activity by transactivation experiments. This information will be critical for the identification of downstream, neuron-specific genes and evaluation of AS- C homologs expression as the nodal point in neurogenesis. Studies of the homologs of Notch and AS-C genes during the retinal development will help us in our long term goal of obtaining a comprehensive picture of the molecular events underlying neurogenesis and cell-type specification. The information obtained from these studies will help us in understanding some of the processes involved in retinal degeneration and formulated hypotheses regarding interventions at the molecular and cellular levels to prolong and promote the survival of specific neurons by recapitulation of developmental mechanisms during retinal degeneration.

神经元多样性的获取对于发展和 哺乳动物中枢神经系统（CNS）的组织。 我们的 了解这种多样性的某些机制 神经元的研究极大地促进了实现的实现 视网膜的分化，是CNS的特征良好模型。 使用逆转录病毒对神经元前体进行神经元前体的谱系分析 细胞类型期间的感染和进行性谱系限制 规格。 但是，我们对分子基础的理解 这些过程尚不清楚有关 涉及哺乳动物神经发生的基因。 其中一种方法是 识别和研究哺乳动物的视网膜特异性表达 果蝇基因的同源物在神经发生中的作用很好 通过突变分析建立。 取决于它们的时空 早期神经发生过程中的表达和功能这些基因属于 两个不同的类别，即achaete-cute（AS-C）的额定基因 复杂编码基本螺旋环螺旋的转录因子 （BHLH）类和Notch是成员的神经源基因， 编码膜蛋白。 胸腔和神经源的成员 基因已被证明在发展中起着重要作用 果蝇的眼睛。 这些基因在早期神经发生中的功能 一般和眼睛的发育尤其使他们 哺乳动物的同源物理想的候选者 AS-C和Notch的哺乳动物同源物的时空表达 开发视网膜中的基因，以了解其细胞特异性 表达并提出有关其功能的假设。 两个都 基因可能参与介导细胞间相互作用 视网膜神经发生和细胞类型规范。 而AS-C同源物 可以通过影响基因组，缺口来激活差异程序 另一个可以将基因组激活f与 进行分化的微环境。 为了 为了评估这种可能性，这些基因的表达将是 在体外研究，以应对已经 显示以调节视网膜中的细胞增殖和分化。 这 AS-C同源物，类似于肌原基因，Myod可能充当主 参与下游神经元特异性激活的调节基因 神经发生早期阶段的前体中的基因。 这 假设将通过分析AS-C的能力来最初测试的LBS。 在开发视网膜以与假定的顺式相互作用方面表达的同源物 作用元素（e-box），并通过 反式激活实验。 此信息对 鉴定下游，神经元特异性基因和AS-评估 c同源物作为神经发生的淋巴结点。 研究 视网膜发育过程中Notch和AS-C基因的同源物将有助于 我们的长期目标是获得有关 神经发生和细胞类型规范的分子事件。 从这些研究中获得的信息将有助于我们理解 视网膜变性并配制的一些过程 关于分子和细胞水平干预措施的假设 通过概括延长和促进特定神经元的存活 视网膜变性过程中的发育机制。