Regulation of cell polarity during neurulation

描述(申请人提供)：神经形成被定义为一系列的形态发生运动，导致神经管的形成，神经管是构成整个成人中枢神经系统的雏形的背部中空神经索。在鸡和小鼠胚胎的后部，神经形成涉及间充质细胞凝聚形成髓索。这一过程(称为次级神经形成)在细胞和形态水平上类似于斑马鱼的神经形成模式。尽管进行了几十年的研究，但这种类型神经形成的遗传基础仍然知之甚少。斑马鱼神经管的形成依赖于细胞适当极化的能力。极性首先表现为定向膜突起的延伸，从而推动神经细胞向背侧中线汇聚。一旦这些间充质细胞结合成神经棒，它们就会转变为上皮样结构，建立一个明确的心尖-基底轴。这项提议的总体目标是了解细胞极性在神经形成过程中是如何调节的，以及这种极性的破坏如何扰乱塑造神经管和神经细胞结构的形态发生运动。在目标1中，我们建议对舌状细胞进行定位克隆和表征，舌状细胞是正常神经收敛所必需的。我们假设LIN稳定神经细胞中的微管，从而使细胞运动极化。在目标2中，我们将研究Par3在上皮化过程中将中心体定位在顶端皮质中的一个新角色。我们将确定中心体定位所需的Par3相互作用蛋白，并确定Par3是否以微管依赖的方式调节这一过程。在目标3中，我们探索了中线组织在提供一种假定的化学吸引线索方面的作用，该线索引导细胞在神经收敛过程中。这些细胞和分子研究最终将增加我们对人类神经管出生缺陷的病因的理解。 公共卫生相关性：神经形成被定义为一系列形态发生运动，导致神经管的形成，神经管是构成整个成人中枢神经系统的雏形的背部中空神经索。鉴于人类脊髓后部畸形的发生率很高，了解二次神经形成的机制是必不可少的。然而，尽管几十年的研究，这种类型的神经形成的细胞和遗传基础仍然知之甚少。这项研究计划的目标是使用斑马鱼中可用的各种遗传工具和标记技术，来研究次级神经形成的机制。这些研究最终将增加我们对神经形成是如何编排的理解，并为探索人类后部神经管缺陷的病因提供分子基础。

DESCRIPTION (provided by applicant): Neurulation is defined as a series of morphogenetic movements that result in the formation of the neural tube, a dorsal hollow nerve cord that constitutes the rudiment of the entire adult central nervous system. In the posterior region of the chick and mouse embryo, neurulation involves the condensation of mesenchymal cells to form a medullary chord. This process (termed secondary neurulation) resembles, at a cellular and morphological level, the mode of neurulation in the zebrafish. Despite decades of research, the genetic basis for this type of neurulation remains poorly understood. Formation of the neural tube in the zebrafish is dependent on the ability of cells to polarize properly. Polarity is first manifested by the extension of directional membrane protrusions that drive neural cell convergence towards the dorsal midline. Once these mesenchymal cells have coalesced into a neural rod, they transition into an epithelial configuration, establishing a clearly defined apico-basal axis. The overall goal of this proposal is to understand how cell polarity is regulated during neurulation and how disruption of this polarity perturbs both the morphogenetic movements that shape the neural tube and neural cytoarchitecture. In aim 1, we propose to positionally clone and characterize linguini, a locus required for proper neural convergence. We hypothesize that lin stabilizes microtubules in neural cells, thereby polarizing cell movement. In aim 2, we will investigate a novel role for Par3 in positioning the centrosome at the apical cortex during epithelialization. We will identify Par3-interacting proteins required for centrosome positioning and determine whether Par3 regulates this process in a microtubule-dependent manner. In aim 3, we explore the role of midline tissues in providing a putative chemoattractive cue that guides cells during neural convergence. These cellular and molecular studies will ultimately increase our understanding of the etiology underlying human neural tube birth defects. PUBLIC HEALTH RELEVANCE: Neurulation is defined as a series of morphogenetic movements that result in the formation of the neural tube, a dorsal hollow nerve cord that constitutes the rudiment of the entire adult central nervous system. Knowledge of the mechanisms of secondary neurulation is essential, given the high incidence of human posterior spinal cord malformations. However, despite decades of research, the cellular and genetic basis for this type of neurulation remains poorly understood. The goal of this research proposal is to use the various genetic tools and labeling techniques available in the zebrafish, to investigate the mechanisms underlying secondary neurulation. These studies will ultimately increase our understanding of how neurulation is orchestrated and provide a molecular basis for exploring the etiology of posterior neural tube defects in humans.