The biomechanics of morphogenesis in the frog

描述（由申请人提供）：本提案的目标是整合形态发生的生物力学，这些生物力学跨越许多尺寸尺度，从亚细胞产生的力到宏观力和引导发育中的青蛙胚胎中的会聚和延伸的大块组织特性。我们建议解决一系列的问题，所产生的生物力学分析的中外侧细胞嵌入及其对组织变形的影响，并建立一个工具包，为未来的生物力学分析形态。 极化突起产生的力是什么？它们是如何转化为细胞的中外侧嵌入的？这个问题涉及原肠胚形成过程中力的细胞起源。为了解决这些力量在原肠胚形成过程中，我们将适应“力牵引”显微镜技术与青蛙胚胎外植体和联合收割机图像的牵引力与高分辨率成像的细胞突起在这些外植体中的中外侧细胞嵌入。 为了理解局部力的产生如何影响组织运动，我们需要了解力学背景，即发育中胚胎组织的粘弹性以及它们如何与组织结构相关。要确定的3D组织结构，负责组织材料的属性的关键功能，我们建议测量背中胚层的散装机械性能和评估与组织学的组织结构的相关功能。 最后，我们想了解组织结构是如何调节伸展活动转化为组织伸展的整体力的。为了测试假设之间的相互作用的细胞行为和组织的扩展，我们建议测量的力量，完整的外植体治疗后，改变扩张活动，局部力的产生，或组织材料的性能。 在这项工作中建立的实验框架将补充正在进行的研究的分子调节器的收敛和扩展提供“螺母和螺栓”模型的形态与可检验的假设。我们的生物力学方法还将解决组织工程领域的基本问题，即胚胎组织中机械特性的来源，并提出胚胎如何构建复杂组织的相关案例研究。

DESCRIPTION (provided by applicant): The goal of this proposal is to integrate the biomechanics of morphogenesis across a number of size-scales from subcellular generation of forces to the macroscopic forces and bulk tissue properties that guide convergence and extension in the developing frog embryo. We propose to address a series of questions that arise from a biomechanical analysis of mediolateral cell intercalation and its effects on tissue deformation and establish a toolkit for future biomechanical analyses of morphogenesis. What are the forces generated by polarized protrusions and how are they converted into mediolateral cell intercalation? This question concerns the cellular origin of force during gastrulation. To resolve these forces during gastrulation we will adapt "force-traction" microscopy techniques for use with frog embryo explants and combine images of traction-forces with high resolution imaging of cell protrusions during mediolateral cell intercalation in these explants. In order to understand how local force generation effects tissue movement we need to understand the mechanical context, i.e. the viscoelastic properties of tissues in the developing embryo and how they relate to tissue architecture. To identify key features of the 3D tissue architecture that are responsible for tissue material properties we propose to measure bulk mechanical properties of the dorsal mesoderm and assess with histology the features of the tissue architecture that are relevant. Lastly, we want to understand how the tissue architecture modulates conversion of protrusive activity into the bulk forces of tissue extension. In order to test hypotheses on the interactions between cell behaviors and tissue extension we propose to measure the force of extension of intact explants after treatments that alter protrusive activity, local force generation, or tissue material properties. The experimental framework established in this work will complement ongoing studies of the molecular regulators of convergence and extension by providing "nuts-and-bolts" models of morphogenesis with testable hypotheses. Our biomechanical approach will also address basic questions from the field of tissue engineering on the source of mechanical properties in embryonic tissues and presents a relevant case study of how embryos build a complex tissue.