Mechanism of vertebrate neural tube morphogenesis

脊椎动物神经管形态发生机制

• 批准号: 7028253
• 负责人: John B Wallingford
• 金额: $ 26.38万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7028253
• 关键词: Xenopus; apical membrane; biological signal transduction; cell morphology; cellular polarity; confocal scanning microscopy; embryogenesis; gene expression; histogenesis; microfilaments; molecular /cellular imaging; molecular assembly /self assembly; neural plate /tube; protein structure function; vertebrate embryology

DESCRIPTION (provided by applicant): The long-term goal of our research is to understand the molecular and cellular mechanisms governing morphogenesis of the neural tube in vertebrate embryos. The proposed experiments are significant because failure of neural tube morphogenesis is the second most common human birth defect. Our focus is on a cell shape change called apical constriction, a conversion of columnar cells into wedge-shaped cells, that contributes importantly to neural tube closure. Apical constriction involves accumulation of actin filaments at the apical surface of polarized epithelial cells. The molecular mechanisms underlying this process are unknown, but we have shown that a single protein, Shroom, is sufficient to induce both apical actin assembly and apical constriction. Shroom is essential for neural tube closure. This proposal aims to understand how Shroom-mediated reorganization of the actin cytoskeleton influences cell shape changes that are necessary for neural tube closure. We propose to determine the molecular mechanisms of Shroom-mediated actin assembly. We hypothesize that the actin regulators, Arp2/3, formin, and Mena are required for this process. We will test this using a gain-of-function assay for Shroom activity and inhibitors of the actin regulatory proteins. We suggest that cell behaviors associated with apical constriction are inter-related and controlled by Shroom. We will address this with loss-of-function experiments in Xenopus embryos and confocal imaging. Finally, we suggest that a Shroom-related gene, called APXL, controls apical constrictions in cells that lack Shroom expression. We will use both gain- and loss-of-function strategies to test this hypothesis. This work will help to elucidate the regulatory networks that govern cell shape-change in general and neural tube closure in particular. Moreover, this work has the potential to shed light on the underpinnings of human neural tube defects.

描述（由申请人提供）：我们研究的长期目标是了解脊椎动物胚胎中神经管形态发生的分子和细胞机制。提出的实验很重要，因为神经管形态发生的失败是第二大常见的人类先天缺陷。我们的重点是称为顶部收缩的细胞形状变化，这是将柱状细胞转化为楔形细胞的转化，这对神经管闭合有重要作用。顶部收缩涉及肌动蛋白丝在极化上皮细胞的顶部表面积累。该过程为基础的分子机制尚不清楚，但我们已经表明，单个蛋白质造型足以诱导根尖肌动蛋白组装和顶端收缩。校友对于闭合神经管是必不可少的。该提案旨在了解裂缝介导的肌动蛋白细胞骨架的重组如何影响神经管闭合所必需的细胞形状变化。我们建议确定裂室介导的肌动蛋白组件的分子机制。我们假设此过程需要肌动蛋白调节剂ARP2/3，FOLIN和MENA。我们将使用功能收益测定法对扫缝活性和肌动蛋白调节蛋白的抑制剂进行测试。我们建议，与顶端收缩相关的细胞行为相互关联并由剪切室控制。我们将通过在Xenopus胚胎和共聚焦成像中的功能丧失实验来解决此问题。最后，我们建议一个称为APXL的裂缝相关基因控制缺乏裂缝表达的细胞中的顶端收缩。我们将同时使用功能丧失策略来检验这一假设。这项工作将有助于阐明一般和神经管闭合细胞形状变化的调节网络。此外，这项工作有可能阐明人类神经管缺陷的基础。