Novel regulators of apical constriction

描述(申请人提供)：这项建议涉及导致脊椎动物胚胎顶端收缩细胞形成的分子机制。根尖收缩是一个过程，在这个过程中，细胞的顶面缩小，导致细胞呈楔形。这些协调的细胞形状变化在整个发育过程中驱动了许多形态发生过程，然而，人们对顶端收缩如何在细胞和分子水平上进行调控知之甚少。我们对非洲爪哇原肠形成初期胚孔形成的初步研究确定了顶端收缩的特定候选调节因子，并揭示了与Wnt信号的联系。我们建议鉴定顶端收缩途径的新成分，并评估在原肠形成过程中对胚孔形成所识别的候选分子的需求。这些实验将在非洲爪哇胚胎中进行，这是唯一适合对其进行生化、细胞生物学和功能分析的胚胎 在体内的过程。一种无偏见的、基于候选基因的表达克隆方法将被用来确定新的根尖收缩调节因子，它们在根尖收缩中的作用将在功能丧失研究中得到证实。基于上位性分析，这些新的分子成员将被定位在一条分子途径上，该途径导致在上皮细胞顶端区域协调Rho信号和肌动球蛋白收缩的空间调节。拟议的实验将重建脊椎动物上皮细胞在早期发育过程中导致根尖收缩的分子途径，并建立PCP蛋白在根尖收缩中的新功能。这些研究将有助于预防出生异常所需的知识，如神经管闭合缺陷，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.