Regulation of organogenesis through regional variations in tissue mechanics

摘要 拟议研究的长期目标是了解调节器官发生的机制。 该提案的总体目标是使用我们的新的体内力传感器，其允许定量的 测量活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，以牙齿为模型， 系统中心假设是，压缩和拉伸的内生区域变化 组织中的应力控制发育中牙齿中核雅普定位的分布，从而 规范关键信令中心的规格。以下具体目标将采用以下组合 设计用于测量体内和原位机械应力的新技术， 遗传策略。目标1将描述内生压缩和拉伸的区域差异 牙齿发育过程中的应力。这些实验将构成有史以来第一次测量区域 任何脊椎动物器官形成过程中压应力和张应力的差异。这些区域 力学的变化将与雅普核在组织中定位的空间变化有关， 建立信号中心。AIM2将确定信号中心的分子调控 在体内发育的牙齿中通过拉伸和压缩应力形成。为了将体内 应力测量的分子控制的机械表型，我们将首先图像 参与力产生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，并确定这些基因中的突变如何影响雅普定位和YAP的表达。 在组织中产生压缩和拉伸应力的能力。目标3将揭示机械的作用 应激在调节体内细胞核与细胞质雅普定位中的作用。这些实验将 直接检验我们的假设，即组织中压应力和拉应力的区域差异控制了 核雅普定位的组织分布。总之，这些研究将为我们提供一个飞跃， 了解牙齿发育如何受到新信号（机械应力）的调节。这些信息关于 牙齿发育的基础生物学将反过来增强未来在诸如牙齿发育等应用方面的努力。 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.