CELL MOTILITY AND CELL INTERACTIONS DURING NEURULATION

这项研究的主要目的是描述胚胎 塑造早期神经系统的细胞运动。 的具体目标 是描述产生神经细胞运动的类型， 非洲爪蟾的神经板的运动， 并了解细胞间的相互作用模式， 行为，以及所选区域神经标记的表达。 这些目标将通过使用新技术来实现， 记录细胞运动和细胞接触相互作用， 组织，其中细胞行为和 可以确定组织形式的变化。 我们将标记非洲爪蟾细胞 用荧光素葡聚糖胺或DiI（活体荧光染料）和接枝物 转化为白化病宿主。 三种类型的神经板外植体将 然后在选定的阶段进行，每个阶段允许表达一个，两个， 或三个基本的形态发生过程， 神经系统 标记细胞的运动性将被成像， 记录使用低光，荧光显微镜，图像处理和 光学存储盘记录。 具体的运动类型将是 根据其表达的空间和时间模式来定义。 控制这些事件的局部组织相互作用将被发现， 显微外科改变组织关系和监测标记 通过特异性抗体或通过原位杂交来定位 特定基因产物 这些结果将解决基本的， 力产生，个别细胞的运动行为，产生 塑造神经系统的力量，并展示它们是如何协调的， 与神经系统的区域化有关。 在解决 神经形成的细胞力学，这些研究将有助于遗传 和分子分析，并用于了解近端， 神经管缺陷的细胞力学原因。

The broad objective of the proposed research is to describe the embryonic cell motility that shapes the early nervous system. The specific goals are to describe the types of neural cell motility that generate the movements of the neural plate of the African clawed frog, Xenopus laevis, and to learn what cell interactions pattern and control these motile behaviors, as well as the expression of selected regional neural markers. These goals will be achieved by using new technology that allows direct recording of the cell motility and cell contact interactions in explanted tissues, where the mechanical relationships between cell behaviors and change in tissue form can be determined. We will label Xenopus cells with fluorescein dextran amine or DiI (vital, fluorescent dyes) and graft them into albino hosts. Three types of explants of the neural plate will then be made at selected stages, each allowing expression of one, two, or three basic morphogenetic processes that function in shaping the nervous system. The motility of the labeled cells will be imaged and recorded using low-light, fluorescence microscopy, image processing and optical memory disc recording. Specific types of motility will be defined in terms of their spatial and temporal patterns of expression. Local tissue interactions controlling these events will be discovered by microsurgically changing tissue relationships and monitoring marker expression by specific antibodies or by in situ hybridization to localize specific gene products. These results will resolve the fundamental, force-producing, motile behaviors of individual cells that generate the forces shaping the nervous system and show how they are coordinated and related to regionalization of the nervous system. In resolving the cytomechanics of neurulation, these studies will contribute to genetic and molecular analyses and be of use in understanding the proximal, cytomechanical causes of neural tube defects.