MOLECULAR STUDIES OF RETINAL DEVELOPMENT

视网膜发育的分子研究

• 批准号: 2164093
• 负责人: Iqbal Ahmad
• 金额: $ 9.47万
• 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 1998-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2164093
• 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; 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.

神经元多样性的获得是发育和发育的核心 哺乳动物中枢神经系统(CNS)的组织。我们的 对这种多样性形成的一些机制的理解 对神经元的研究极大地促进了这一成就 视网膜的分化，这是一个很好的中枢神经系统模型。 利用逆转录病毒对体内神经前体细胞的谱系分析 细胞型过程中的感染和进行性谱系限制 规格。然而，我们对分子基础的理解 这些进程仍然不清楚，因为缺乏关于以下方面的信息 与哺乳动物神经发生有关的基因。其中一种方法是 鉴定和研究哺乳动物视网膜特异性表达 果蝇基因在神经发生中的作用一直很好 通过突变分析确定。取决于它们的时空 这些基因在早期神经发生中的表达和功能 无毛类(AS-C)的两个不同的神经基因 编码碱性螺旋-环-螺旋转录因子的复合体 (BHLH)类和Notch所属的神经源性基因，即 编码一种膜蛋白。神经性和神经源性的成员 基因已被证明在癌症的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作用 特别是在眼睛的发育过程中，使他们的眼睛 哺乳动物同源基因研究的理想候选者 哺乳动物AS-C和Notch同源物的时空表达 视网膜发育中的基因，以了解其细胞特异性 并提出关于其功能的假说。两者都有 基因可能参与调节细胞间的相互作用 视网膜神经发生和细胞类型规范。而As-C同系物 可以通过影响基因组来激活分化程序，Notch 另一方面，HAD可以将基因组的激活与 分化发生的微环境。按顺序 为了评估这种可能性，这些基因的表达将是 在体外研究对各种生长因子的反应 被证明能调节视网膜中的细胞增殖和分化。这个 作为肌源性基因的同源物，MyoD可能作为主控基因发挥作用 参与下游神经元特异性激活的调控基因 神经发生早期阶段前体中的基因。这 假设将通过分析AS-C的能力来初步检验LBS 在发育中的视网膜表达的同源物与推测的顺式作用- 作用元件(E-box)及其转录活性的评价 变态实验。这一信息将对 下游神经元特异性基因的鉴定和AS-1的评估 C同源基因的表达作为神经发生的结点。对中国传统文化的研究 视网膜发育过程中Notch和AS-C基因的同源基因将有助于 我们的长期目标是全面了解 神经发生的分子事件和细胞类型规范。 从这些研究中获得的信息将有助于我们理解 一些参与视网膜退行性变的过程和公式 关于分子和细胞水平干预的假设 通过重述延长和促进特定神经元的存活 视网膜退化过程中的发育机制。