Regulation of organogenesis through regional variations in tissue mechanics

摘要 这项拟议研究的长期目标是了解器官发生的调控机制。 这项提议的总体目标是使用我们新型的在体力传感器，它允许量化 测量活的胚胎组织内的机械应力，以揭示机械信号的作用 在器官形态发生过程中的信号中心和细胞类型的规范中，以牙齿为模型 系统。中心假设是压缩和拉伸的内生区域差异 组织中的应力控制着核YAP在发育牙中的定位分布，从而 规范关键信令中心规范。以下具体目标将采用以下组合 利用先进的小鼠在体内和原位测量机械应力的新技术 遗传策略。目标1将描述内源压缩和拉伸的地区差异 牙齿发育过程中的压力。这些实验将构成有史以来第一次地区性测量 脊椎动物器官形成过程中压应力和拉应力的差异。这些地区 力学的变化将与组织中YAP核定位的空间差异和 建立信令中心。目标2将决定信号中心的分子控制 在活体发育的牙齿中由拉应力和压应力形成。为了将体内的 控制机械表型的分子的应力测量，我们将首先想象 与力产生有关的蛋白质的时空分布。此外，我们将从基因上删除 编码这些蛋白质的基因，并确定这些基因的突变如何影响YAP的定位和 在组织中产生压应力和拉应力的能力。目标3将揭示机械的作用 在体内核与胞质YAP定位的调节中的压力。这些实验将 直接测试我们的假设，在组织控制中压应力和拉应力的区域差异 核YAP定位的组织分布。总而言之，这些研究将使我们的 了解牙齿发育是如何由一种新的信号--机械应力--调节的。关于这些信息的 牙齿发育的基础生物学将反过来加强未来在牙齿等应用方面的努力 生物工程。

ABSTRACT The long-term goal of the proposed research is to understand the mechanisms that regulate organogenesis. The overall objective of the proposal is to use our novel in vivo force transducers, which allow quantitative measurements of mechanical stresses within living embryonic tissues, to unveil the role of mechanical signals in the specification of signaling centers and cell types during organ morphogenesis, using the tooth as a model system. The central hypothesis is that the endogenous regional variations in compressive and tensile stresses in the tissue control the distribution of nuclear YAP localization in the developing tooth, thereby regulating specification of key signaling centers. The following Specific Aims will employ a combination of novel technologies designed to measure mechanical stresses in vivo and in situ with sophisticated mouse genetic strategies. Aim 1 will characterize regional differences in endogenous compressive and tensile stresses during tooth development. These experiments will constitute the first ever measurement of regional differences in compressive and tensile stresses during the formation of any vertebrate organ. These regional changes in mechanics will be related to spatial variations in YAP nuclear localization in the tissue and the establishment of signaling centers. Aim 2 will determine the molecular control of signaling center formation by tensile and compressive stresses in the developing tooth in vivo. In order to link the in vivo stress measurements to the molecules controlling the mechanical phenotype, we will first image the spatiotemporal distribution of proteins involved in force generation. Moreover, we will genetically delete the genes encoding these proteins and determine how mutations in these genes affect YAP localization and the ability to generate compressive and tensile stresses in the tissue. Aim 3 will reveal the role of mechanical stresses in the regulation of nuclear vs. cytoplasmic YAP localization in vivo. These experiments will directly test our hypothesis that regional differences in compressive and tensile stresses in the tissue control the tissue distribution of nuclear YAP localization. Together, these studies will provide a leap forward in our knowledge of how tooth development is regulated by a novel signal, mechanical stress. Such information about the fundamental biology of tooth development will in turn enhance future efforts in applications such as tooth bioengineering.