Novel regulators of apical constriction

描述（由申请人提供）：该建议涉及导致脊椎动物胚胎中顶端收缩细胞形成的分子机制。顶端缩窄是一个过程，在此过程中，细胞的顶端表面减少，导致细胞呈楔形。这些协调的细胞形状变化驱动许多形态发生过程，然而，很少有人知道顶端收缩是如何在细胞和分子水平上调节的。我们的初步研究，在非洲爪蟾原肠胚形成的发病确定特定的候选调节顶端收缩，并揭示了Wnt信号的连接。我们建议确定新的组件的顶端收缩途径和评估的要求，确定候选分子在胚孔形成原肠胚形成。这些实验将在非洲爪蟾胚胎中进行，非洲爪蟾胚胎独特地适合于生物化学，细胞生物学和功能分析。 体内过程。将进行一种无偏见的和基于候选人的表达克隆方法，以鉴定顶端收缩的新调节因子，并在功能丧失研究中证实它们在顶端收缩中的作用。基于上位性分析，这些新的分子球员将被定位在一个分子途径，导致协调的空间调节Rho信号和肌动球蛋白收缩在上皮细胞的顶端域。拟议的实验将重建分子通路，导致在脊椎动物上皮细胞在早期发育过程中的顶端收缩，并建立一个新的功能，PCP蛋白在顶端收缩。这些研究将有助于预防出生异常（如神经管闭合缺陷）的必要知识，并将与人类癌症疾病相关。

DESCRIPTION (provided by applicant): This proposal concerns molecular mechanisms leading to the formation of apically constricted cells in the vertebrate embryo. Apical constrictio is a process, during which the apical surface of a cell is reduced causing the cell to take on a wedged shape. These coordinated cell shape changes drive many morphogenetic processes throughout development, however, little is known about how apical constriction is regulated at the cellular and molecular level. Our preliminary studies of blastopore formation at the onset of Xenopus gastrulation identified specific candidate regulators of apical constriction and revealed a connection to Wnt signaling. We propose to identify novel components of the apical constriction pathway and evaluate the requirement for the identified candidate molecules in blastopore formation during gastrulation. These experiments will be carried out in Xenopus embryos, which are uniquely suited for biochemical, cell biological and functional analysis of this process in vivo. An unbiased and candidate-based expression cloning approach will be carried out to identify novel regulators of apical constriction and their role in apical constriction will e confirmed in loss-of-function studies. Based on epistatic analysis, these new molecular players will be positioned in a molecular pathway that leads to coordinate spatial regulation of Rho signaling and actomyosin contractility in the apical domains of epithelial cells. The proposed experiments will reconstruct molecular pathways leading to apical constriction in vertebrate epithelial cells during early development and establish a novel function for PCP proteins in apical constriction. These studies will contribute to the knowledge necessary for prevention of birth abnormalities such as neural tube closure defects and will be relevant to human cancer disease.