Characterizing the fundamental mechanisms of epithelial invagination during ocular morphogenesis

项目摘要 与许多器官相比，眼睛的生成更需要对其形状的精确控制，以实现最佳功能。 因此，了解眼睛和晶状体在胚胎发育过程中是如何构成的 有助于描述导致主要结构缺陷或更多结构缺陷的眼睛异常的性质 改变视觉的细微变化。器官生成所需的形态发生事件的一个例子是 上皮性内陷。这一过程驱使几个早期器官系统的上皮细胞向内弯曲。 包括眼睛发育早期的晶状体胎盘。尽管有几种机制已经被 有人提出了推动这一过程的机制，如根尖收缩或局部胎盘生长，但尚未发现 足以解释上皮细胞的弯曲。我们最近观察到胎盘细胞会改变形状， 以平面极化方式移动并产生细胞骨架结构，从而产生细胞的净流 朝向中央的位置。像这样的平面极化细胞运动的特征之一是 细胞花环的形成和分解，这是一种需要空间的有组织的细胞重排过程 收缩和缩短连接的连接蛋白和延长和稳定连接的蛋白的限制 细胞连接。我们已经确定了负责连接的蛋白质的平面极化定位。 收缩(Shroom3和p120-catenin)和稳定(Par3和Cdc42)。这些结果将我们引向了我们的 内陷是由上皮细胞运动和各向异性细胞共同驱动的中心假说 由径向平面极化蛋白质定位、连接收缩和连接组织的形状变化 伸长率。我们将利用实时荧光显微镜对这一中心假设进行三个目的的验证 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 并分析Shroom3和p120连接素联合缺失的后果。目标2的目标是 描述PAR3在玫瑰花结分解和内陷过程中连接伸长中的作用。目标3将 研究各向异性细胞的几何形状和运动是否是由于 诱导连接收缩和连接伸长的蛋白质。一旦完成，这里的实验 该提案将定义驱动晶状体胎盘凹陷机制的细胞行为。

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.