GENETIC AND MOLECULAR STUDIES OF NEUROGENESIS

神经发生的遗传学和分子研究

• 批准号: 2025263
• 负责人: Chris Q Doe
• 金额: $ 25.35万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2025263
• 关键词: DNA binding protein; Drosophilidae; alleles; biochemical evolution; central nervous system; developmental genetics; developmental neurobiology; gene expression; gene mutation; genetic mapping; genetic regulation; laboratory mouse; molecular cloning; neurogenesis; neurogenetics; regulatory gene

The Drosophila central nervous system (CNS) is composed of hundreds of neurons, each expressing a unique combination of neurotransmitters, ion channels, receptors, and cell surface molecule -- with each neuron forming numerous stereotyped contacts with other neurons or muscles. How is this spectacular neuronal diversity generated? Our long term goals are to identify the cellular and molecular mechanisms used to generate neuronal diversity in the Drosophila CNS, and determine whether these mechanisms are conserved in more complex organisms. Drosophila is an ideal organism for investigating CNS development: neurogenesis is relatively simple, with cellular diversity being generated in two steps. First, positional cues in the neuroectoderm control the formation of 25 unique neuronal precursor cells (neuroblasts); second, each neuroblast goes through an invariant cell lineage to generate an average of five ganglion mother cells (GMCs) which each produce a pair of neurons. Each of these two steps contributes to the diversity of cell fate in the CNS, and each step can be studied independently. The proposed research uses several recent technical advanced to investigate both neuroblast and neuronal determination. To understand how positional cues control neuroblast determination, we will make use of recently developed molecular markers that allow each neuroblasts to be uniquely identified, and assay for mutations that alter expression of these markers. In particular, we will focus on the role of the segment polarity gene wingless in the non-autonomous determination of the identified NB4-2 (Specific Aim I). We will also focus on the role of the 5953 gene, which is expressed in the identified NB4-2 in response to the wg positional cue, and is apparently required for NB4-2 determination. To characterize genes controlling lineage-based neuronal determination, we will look for specific alterations in neuroblast cell lineages using a novel cell marking technique to label single identified neuroblast and all of its neuronal progeny. In particular, we will investigate the role of ming, seven-up and prospero genes in the specification of cell fate during the lineage of the identified NB1-1, NB4-2 and NB7-4 (Specific Aim II). In addition, we will use molecular markers for specific neuroblast "sublineages" and mutations in cell cycle control genes to investigate the relationship between transition through the cell cycle and the sequential specification of GMC fate during identified neuroblast lineages (Specific Aim III). We anticipate rapid progress in identifying and characterizing genes controlling the generation of neuronal diversity in the Drosophila CNS due to the relative simplicity of the nervous system molecular markers for individual precursor cells, powerful new techniques for identifying and cloning CNS-expressed genes, and a newly developed cell lineage method that allows wild-type and mutant NB lineages to be directly compared at the level of the axonal projections of every neuron in the linage.

果蝇中枢神经系统（CNS）由数百个 神经元，每个都表达神经递质、离子的独特组合 通道、受体和细胞表面分子——每个神经元 与其他神经元或肌肉形成大量刻板接触。 如何 这种惊人的神经元多样性是产生的吗？ 我们的长期目标 是确定用于产生的细胞和分子机制 果蝇中枢神经系统的神经元多样性，并确定这些是否 机制在更复杂的生物体中是保守的。 果蝇是一种 研究中枢神经系统发育的理想生物体：神经发生是 相对简单，细胞多样性分两步生成。 首先，神经外胚层中的位置信号控制着 25 独特的神经元前体细胞（神经母细胞）；第二，每个神经母细胞 经过不变的细胞谱系平均产生五个 神经节母细胞（GMC），每个细胞产生一对神经元。 每个 这两个步骤有助于中枢神经系统细胞命运的多样性， 并且每个步骤都可以独立研究。 拟议的研究使用了几种最新的技术来 研究神经母细胞和神经元的测定。 要了解 我们将利用位置线索如何控制神经母细胞的决定 最近开发的分子标记使每个神经母细胞 被独特地鉴定，并测定改变表达的突变 这些标记。 我们将特别关注该细分市场的作用 极性基因 wingless 在非自主测定中的应用 鉴定出 NB4-2（具体目标 I）。 我们还将重点关注 5953 基因，该基因在已鉴定的 NB4-2 中表达，以响应 wg 位置提示，显然是 NB4-2 测定所必需的。 为了表征控制基于谱系的神经元决定的基因， 我们将使用以下方法寻找神经母细胞谱系的特定改变 一种新的细胞标记技术，用于标记单个已识别的神经母细胞和 它的所有神经元后代。 我们将特别调查角色 ming、seven-up 和 prospero 基因在细胞命运规范中的作用 在已鉴定的 NB1-1、NB4-2 和 NB7-4 的谱系中（具体目标 二）。 此外，我们将使用特定神经母细胞的分子标记 需要研究的细胞周期控制基因的“亚系”和突变 细胞周期转换与细胞周期之间的关系 识别神经母细胞期间 GMC 命运的顺序规范 谱系（具体目标 III）。 我们预计在识别和表征基因方面会取得快速进展 控制果蝇中枢神经系统神经元多样性的产生 由于神经系统分子标记相对简单 对于单个前体细胞，强大的新技术可以识别 克隆 CNS 表达基因，以及新开发的细胞谱系 允许野生型和突变型 NB 谱系直接 在每个神经元的轴突投影水平上进行比较 血统。