Mechanisms of robustness in organogenesis (Equipment Supplement 2023)

项目总结/摘要 发育具有显著的可重复性，通常产生大小、形状不变的相同器官， 结构和功能。鲁棒性是细胞系统调整和发展的能力 正确的大小和形状的器官在面对随机波动，以及环境和遗传 变化.在缺乏稳健性的情况下，这些扰动将导致器官大小的较大变化， 形状提出的机制，以创造鲁棒性，包括负反馈回路，冗余， 调节网络，协调细胞行为的细胞间信号传导，变异性的时空平均， 和机械信号，所有这些功能都在系统层面上发挥作用，并在 包括人类在内的多细胞生物为了确定鲁棒性如何出现，我们确定了突变体， 器官大小或形状（VOS）的可变性增强，从而破坏稳健性。我们的拟南芥萼片 （最外层花器官）系统非常适合这些研究，因为每株植物产生的 超过100个萼片，允许对单个个体的器官稳健性进行统计分析，这是无法做到的。 在大多数其他系统中。我们的目标是使用这些vos突变体结合创新的定量 生物学方法结合了正在生长的萼片的实时成像，图像处理以量化生长， 计算建模、生物力学测试、分子遗传学和基因组学来阐明机制 产生鲁棒性。我们假设，机械信号和协调的增长可能是 对于器官形状和大小的稳健性尤其重要。(Aim 1）首先，我们将阐明 时空平均中的机械信号以产生鲁棒的器官。基于计算 模型，我们假设适当的机械信号是需要时空平均的细胞 生长变异以产生健壮的器官。我们将使用改变机械结构的突变体来验证这一假设。 与VOS 1突变体结合的信号传导，其抑制时空平均。(Aim（2）第二，我们将 确定同步器官启动的机制，以及它们如何有助于 器官大小vos 2突变体表现出可变的萼片大小和不规则的时间萼片原基的起始。我们将 检验器官大小可变是由于器官启动时间的稳健性丧失所致的假设 通过研究生物力学和激素信号，这两者都有助于原基的启动。 (Aim 3）第三，我们将确定如何协调生长跨越三个维度的器官 有助于形状的鲁棒性。vos 3突变体表现出可变的萼片形状，我们假设这一结果 由于组织层之间生长的不协调导致外部萼片的机械弯曲 面我们将使用计算模型来预测增长率和力学的差异， 引起机械弯曲，并在vos 3中测试这些。总之，这些目标将揭示机制和原则 产生器官大小和形状的健壮性，这是人类发育的基础。

Project Summary/Abstract Development is remarkably reproducible, generally producing the same organ with invariant size, shape, structure, and function in each individual. Robustness is the ability of cellular systems to adjust and develop the correct size and shape organs in the face of stochastic fluctuations, and environmental and genetic variations. In the absence of robustness, these perturbations would cause large variations in organ size and shape. The mechanisms proposed to create robustness include negative feedback loops, redundancy in regulatory networks, intercellular signaling to coordinate cell behaviors, spatiotemporal averaging of variability, and mechanical signaling, all of which function at the systems level and are repeatedly observed in multicellular organisms including humans. To determine how robustness emerges, we identified mutants with enhanced variability in organ size or shape (vos), thus disrupting robustness. Our Arabidopsis thaliana sepal (outermost floral organ) system is uniquely well suited for these studies because each plant produces more than 100 sepals, allowing statistical analysis of organ robustness in a single individual, which cannot be done in most other systems. Our goal is to use these vos mutants in combination with an innovative quantitative biology approach combining live imaging of growing sepals, image processing to quantify growth, computational modeling, biomechanical tests, molecular genetics, and genomics to elucidate mechanisms generating robustness. We hypothesize that mechanical signaling and coordination of growth may be particularly important for robustness of organ shape and size. (Aim 1) First, we will elucidate the role of mechanical signaling in spatiotemporal averaging to produce robust organs. Based on computational modeling, we hypothesize appropriate mechanical signaling is required for spatiotemporal averaging of cellular growth variability to produce robust organs. We will test this hypothesis using mutants that alter mechanical signaling in conjunction with the vos1 mutant, which inhibits spatiotemporal averaging. (Aim 2) Second, we will determine the mechanisms that synchronize organ initiation and how they contribute to robustness of organ size. vos2 mutants exhibit variable sepal size and irregular timing of sepal primordia initiation. We will test the hypothesis that variable organ sizes result from a loss of robustness in the timing of organ initiation through examining biomechanics and hormone signaling, both of which contribute to primordium initiation. (Aim 3) Third, we will determine how coordination of growth across the three dimensions of the organ contributes to robustness in shape. vos3 mutants exhibit variable sepal shapes; we hypothesize this results from perturbed coordination of growth between tissue layers leading to mechanical buckling of the outer sepal surface. We will use computational modeling to predict differences in growth rate and mechanics that can cause mechanical buckling and test these in vos3. Together, these aims will reveal mechanisms and principles generating robustness of organ size and shape, which underlie human development.