Characterizing the fundamental mechanisms of epithelial invagination during ocular morphogenesis

项目摘要 眼睛的产生比许多器官更需要精确控制其形状以实现最佳功能。 因此，了解眼睛和透镜在胚胎发育过程中是如何形成的， 重要的是帮助描述导致主要结构缺陷或更多的眼部异常的性质 改变视力的细微变化。器官生成所需的形态发生事件的一个例子是 上皮内陷这一过程促使几个早期器官系统的上皮细胞向内弯曲 包括早期眼发育过程中的透镜基板。虽然有几种机制， 提出了驱动这一过程，如顶端收缩或局部基板生长，没有发现 足以解释上皮弯曲我们最近观察到基板细胞改变形状， 以平面极化的方式移动并产生细胞骨架结构，从而产生细胞的净流动 向中央基板移动平面极化细胞运动的标志之一是 细胞重排的形成和解决，一个有组织的细胞重排过程，需要空间 限制收缩和缩短连接的连接蛋白和延长和稳定连接的蛋白 细胞连接我们已经确定了负责连接蛋白的平面极化定位。 收缩（Shroom 3和p120-连环蛋白）和稳定（Par 3和cdc 42）。这些结果使我们 内陷是由上皮细胞运动和各向异性细胞的组合驱动的中心假设 由放射状平面极化蛋白定位、连接收缩和连接组织的形状变化 伸长率我们将利用活体荧光显微镜对这一中心假设进行检验， 转基因小鼠胚胎在目标1中，我们将描述各向异性连接收缩的作用 分析Shroom 3和p120 catenin联合缺失的后果。目标2的目标是 表征在玫瑰花结消退和内陷期间Par 3在连接延长中的作用。目标3将 研究各向异性的细胞几何形状和运动是否是由 诱导连接收缩和连接伸长的蛋白质。一旦完成，这个实验 该提案将定义驱动透镜基板内陷机制的细胞行为。

Project Summary Generation of the eye, more so than many organs, requires precise control of its shape for optimal function. Obtaining knowledge of how the eye and lens is constructed during embryonic development is therefore important to help describe the nature of ocular abnormalities that lead to major structural defects or more subtle changes that alter vision. An example of a morphogenetic event required for the generation of organs is epithelial invagination. This process drives the inward bending of epithelia of several early organ systems including that of the lens placode during early ocular development. Although several mechanisms have been proposed to drive this process, such as apical constriction or local placodal growth, none have been found sufficient to account for epithelial bending. We have recently observed that placodal cells change shape, move, and generate cytoskeletal structures in a planar polarized manner that produces a net flow of cells toward the central placode. One of the hallmarks of planar-polarized cell movements such as these is the formation and resolution of cellular rosettes, an organized process of cell rearrangement that requires spatial restriction of junctional proteins that contract and shorten junctions and proteins that lengthen and stabilize cellular junctions. We have identified planar-polarized localization of proteins responsible for junctional contraction (Shroom3 and p120-catenin) and stabilization (Par3 and cdc42). These results led us to our central hypothesis that invagination is driven by a combination of epithelial cell movements and anisotropic cell shape changes organized by radial planar polarized protein localization, junction contraction, and junction elongation. We will test this central hypothesis with three aims utilizing live-fluorescent microscopy of genetically altered mouse embryos. In aim 1 we will characterize the role of anisotropic junctional contraction and analyze the consequences of combined deficiency of Shroom3 and p120 catenin. The goal of aim 2 is to characterize the role of Par3 in junction elongation during rosette resolution and invagination. Aim 3 will investigate whether anisotropic cell geometry and movement results from the mutual antagonism between proteins that induce junctional contraction and junctional elongation. Once completed, the experiments in this proposal will define the cell behaviors that drive the mechanisms of lens placode invagination.