Cadherin interactions in ectodermal derivative fate specification

项目总结/摘要 外胚层开始作为祖细胞的上皮片，并逐渐改变其命运。 细胞变得局限于神经组织，非神经外胚层（NNE），其变成表皮， 基板细胞和神经嵴（NC）细胞。任何未能规范或区分这些 组织可能导致缺陷，如神经管闭合失败，颅面异常，整合， 感觉功能障碍或感觉基板障碍。早期的外胚层祖细胞紧密结合在一起- 它们在自然界中是不同的，但通过形态发生运动，它们分离成多种组织， 神经板卷起并与NNE分离，NC细胞经历上皮细胞向上皮细胞的转移， 间充质转变（EMT）从神经管分离并迁移到神经管的各个部位。 胚胎发育异常的神经和NC发育可以导致许多共同的发育， 视觉障碍，如脊柱裂、肠道无神经节细胞症、白化病和裂 上颚驱动这些组织形成的机制，以及EMT和EMT的过程， 移民受到严格控制，以确保适当的发展。根据以前的研究，我们和 其他人已经确定，粘附分子，特别是N-钙粘蛋白（Ncad）， 和E-钙粘蛋白（Ecad），导致中枢神经系统和NC细胞发育异常。虽然这些 尽管已经在体外癌细胞中对蛋白质进行了很好的研究，但是关于蛋白质的表达缺乏共识。 钙粘蛋白在调节外胚层衍生物发育中的特殊功能 在早期脊椎动物体内发育期间。在这里，我们建议确定Ncad和 Ecad对神经管、NNE和神经嵴的分离和发育起调节作用 细胞，并澄清哪些蛋白质，他们在这些过程中相互作用。对于目标1，我们将使用 获得和鸟类胚胎功能的研究，以测试我们的假设，嗜异性Ecad， Ncad相互作用是外胚层分化为神经、NNE和NC细胞所必需的， 确定它们在NC EMT期间如何相互作用以及与其他钙粘蛋白相互作用。下一个是 我们将使用一种未被充分利用的两栖动物模式生物Ambystoma mexicanum（蝾螈）， 比较钙粘蛋白在早期发育过程中的表达和功能， 目前在外地的差异。这项研究计划使用了经典的胚胎学方法， ods以及两种脊椎动物模式生物，这将允许分析的功能conser- 在脊椎动物物种中的分布。完成拟议的研究后，将可提供大量资料- 着眼于驱动早期命运规范的机制，以及 脊椎动物胚胎的外胚层衍生物。

Project Summary/Abstract The ectoderm begins as an epithelial sheet of progenitor cells, and progressively the fate of its cells become limited to neural tissue, non-neural ectoderm (NNE), which becomes epidermis and placodal cells, and neural crest (NC) cells. Any failure in the specification or differentiation of these tissues can lead to defects such as neural tube closure failure, craniofacial abnormality, integu- ment dysfunction or sensory placode disorders. The early ectodermal progenitors are tightly ad- herent in nature, and yet through morphogenetic movements, they segregate into multiple tissues, the neural plate rolls up and separates from the NNE, the NC cells undergo an epithelial to mes- enchymal transition (EMT) separating from the neural tube and migrating to various sites in the developing embryo. Aberrant neural and NC development can lead to a host of common devel- opmental disorders such as spina bifida, aganglionosis of the intestinal tract, albinism and cleft palate. The mechanisms that drive the formation of these tissues, and the process of EMT and migration, are tightly controlled to ensure proper development. From previous studies, we and others have identified that misregulation of adhesion molecules, specifically N-cadherin (Ncad) and E-cadherin (Ecad), leads to abnormal development of the CNS and NC cells. Although these proteins have been well studied in vitro in cancer cells, there is a lack of consensus about the specific functions cadherin proteins have in regulating the development of ectodermal derivatives during early vertebrate development in vivo. Here, we propose to ascertain the role that Ncad and Ecad play to regulate the segregation and development of the neural tube, NNE and neural crest cells, and to clarify which proteins they interact with in these processes. With Aim 1, we will use gain and loss of function studies in avian embryos to test our hypothesis that heterophilic Ecad- Ncad interactions are required for ectoderm to differentiate into neural, NNE and NC cells, further identifying how they interact with each other and other cadherin proteins during NC EMT. Next, we will use an underutilized amphibian model organism, Ambystoma mexicanum (axolotl), to compare the expression and function of the cadherin proteins during early development and alle- viate current discrepancies in the field. This research proposal uses classic embryological meth- ods as well as two vertebrate model organisms, which will allow for analysis of functional conser- vation across vertebrate species. Completion of the proposed studies will provide substantial in- sights into the mechanisms that drive early fate specification, and the development program of ectodermal derivatives in vertebrate embryos.