Development of Cranial Motor Neurons

颅运动神经元的发育

• 批准号: 6766866
• 负责人: Anand Chandrasekhar
• 金额: $ 21.55万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6766866
• 关键词: animal genetic material tag; biological signal transduction; cell migration; cell transplantation; confocal scanning microscopy; developmental neurobiology; embryo /fetus cell /tissue; fluorescence microscopy; gene induction /repression; gene mutation; genetically modified animals; head; in situ hybridization; motor neurons; neural plate /tube; neurogenesis; protein structure function; skull; transcription factor; zebrafish

DESCRIPTION (provided by applicant): Neuronal induction and migration are fundamental processes in nervous system development, and many human neurological disorders are caused by severe deficiencies in these processes. Our focus is the cranial motor neurons (CMNs), which control vital functions such as chewing, swallowing, and speech in humans. Our long-term goal is to elucidate the cellular and molecular mechanisms underlying the induction and migration of CMNs in the powerful model vertebrate, the zebrafish embryo. Secreted proteins of the sonic hedgehog (Shh) family are essential for vertebrate motor neuron induction. However, little is known about the mechanisms by which Shh signaling pathway components, including the Gli1 and Gli2 transcription factors, specify different types of motor neurons (CMNs and spinal motor neurons (SMNs)) along the anterior-posterior axis of the neural tube. The cellular mechanisms underlying tangential migration of CMNs following induction are equally obscure. Our preliminary studies demonstrate that the zebrafish detour (dtr/gli 1) and you-too (yot/gli2) genes have specific functions in CMN and SMN induction, and that mutations in the trilobite (tri) and valentino (val) genes disrupt particular events during tangential CMN migration. The studies we propose here will define the mechanisms of CMN specification and tangential migration. (1) We will determine whether Gli1 and Gli2 are necessary and sufficient for CMN and SMN induction (a) by characterizing motor neuron development in yot mutants, (b) by determining whether gli1 and gli2 are co-expressed in motor neurons, and (c) by analyzing CMN and SMN induction in dtr; yot double mutants, and following gli1 and gli2 overexpression in wildtype and dtr mutant embryos. (2) We will evaluate the function of Shh pathway components encoded by the chameleon (con) and iguana (igu) genes in CMN and SMN induction. (3) We will determine whether the CMN migration defects of tri and val mutants are caused by specific defects in dynamic cellular behaviors (a) by genetic mosaic analysis of tri mutants, and (b) by analyzing dynamic cellular behaviors of migrating CMNs in wildtype, and tri and val mutant embryos by time-lapse microscopy. The availability of key zebrafish mutants, the ability to employ gain- and loss-of-function approaches, the optical clarity of the zebrafish embryo, and the ability to perform genetic mosaic analysis and time-lapse microscopy represent a powerful combination of tools that will enable us to define the functions of particular genes in CMN development at the cellular and molecular levels. Our studies on motor neuron induction and migration will provide fundamental insights into the mechanisms underlying these processes essential for normal brain development and function.

描述（由申请人提供）：神经元诱导和迁移是 神经系统发育的基本过程，许多人类 神经系统疾病是由这些过程中的严重缺陷引起的。 我们的重点是颅运动神经元（CMNs），控制重要功能 如人类的咀嚼、吞咽和言语。我们的长期目标是 阐明诱导的细胞和分子机制， CMN在强大的模式脊椎动物斑马鱼胚胎中的迁移。 分泌蛋白质的音刺猬（嘘）家庭是必不可少的， 脊椎动物运动神经元诱导。然而，人们对此知之甚少。 Shh信号通路成分，包括Gli 1和 Gli 2转录因子，指定不同类型的运动神经元（CMN和 脊髓运动神经元（SMN））沿着神经前-后轴 管材. CMN切向迁移的细胞机制 归纳法同样晦涩难懂。我们的初步研究表明， 斑马鱼detour（dtr/gli 1）和you-too（yot/gli 2）基因具有特异性 在CMN和SMN诱导中起作用，并且三叶虫（tri）中的突变 和valentino（瓦尔）基因在切向CMN期间破坏特定事件 迁移我们在这里提出的研究将定义CMN的机制 规范和切线迁移。(1)我们将确定Gli 1和 Gli 2是CMN和SMN诱导的必要和充分条件（a） 表征yot突变体中的运动神经元发育，（B）通过测定 gli 1和gli 2是否在运动神经元中共表达，以及（c）通过分析 dtr; yot双突变体中的CMN和SMN诱导，以及在gli 1和gli 2之后 在野生型和DTR突变胚胎中的过表达。(2)我们将评估 由变色龙（con）和鬣蜥编码的Shh通路组分的功能 (igu)CMN和SMN诱导中的基因。(3)我们将确定CMN是否 tri和瓦尔突变体的迁移缺陷是由 动态细胞行为（a）通过三突变体的遗传镶嵌分析，和 (b)通过分析野生型中迁移CMN的动态细胞行为， tri和瓦尔突变体胚胎。提供关键 斑马鱼突变体，采用获得和丧失功能方法的能力， 斑马鱼胚胎的光学清晰度， 镶嵌分析和延时显微镜是一个强大的组合， 这些工具将使我们能够定义CMN中特定基因的功能 在细胞和分子水平上的发展。运动神经元的研究 诱导和迁移将提供对机制的基本见解 这些过程对正常的大脑发育和功能至关重要。