Regulation of cell polarity during neurulation

描述（由申请人提供）：神经形成被定义为导致神经管形成的一系列形态发生运动，神经管是构成整个成人中枢神经系统雏形的背侧中空神经索。在鸡和小鼠胚胎的后部区域，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）在细胞和形态学水平上类似于斑马鱼的神经形成模式。尽管经过了几十年的研究，这种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的正常生长能力。极性首先表现为定向膜突起的延伸，其驱动神经细胞朝向背中线会聚。一旦这些间充质细胞合并成神经杆，它们就转变成上皮结构，建立起明确的顶端-基底轴。这项建议的总体目标是了解细胞极性是如何在神经形成过程中进行调节，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，我们建议定位克隆和表征linguini，适当的神经收敛所需的轨迹。我们假设lin稳定了神经细胞中的微管，从而极化了细胞运动。在目标2中，我们将研究Par 3在上皮形成过程中将中心体定位在顶端皮质的新作用。我们将确定中心体定位所需的Par 3相互作用蛋白，并确定Par 3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个假定的化学吸引线索，引导细胞在神经会聚过程中的作用。这些细胞和分子研究将最终增加我们对人类神经管出生缺陷病因学的理解。 公共卫生相关性：神经形成被定义为导致神经管形成的一系列形态发生运动，神经管是构成整个成人中枢神经系统的雏形的背侧中空神经索。鉴于人类脊髓后部畸形的高发病率，了解继发性神经形成的机制是必要的。然而，尽管经过几十年的研究，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利用斑马鱼中可用的各种遗传工具和标记技术，研究次级神经胚形成的机制。这些研究将最终增加我们对神经形成是如何编排的理解，并为探索人类后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.