Abstract:
Anteroposterior (AP) elongation of the vertebrate body plan is driven by convergence and extension (C&E) gastrulation movements in both the mesoderm and neuroectoderm, but how or whether molecular regulation of C&E differs between tissues remains an open question. Using a zebrafish explant model of AP axis extension, we show that C&E of the neuroectoderm and mesoderm can be uncoupled ex vivo, and that morphogenesis of individual tissues results from distinct morphogen signaling dynamics. Using precise temporal manipulation of BMP and Nodal signaling, we identify a critical developmental window during which high or low BMP/Nodal ratios induce neuroectoderm- or mesoderm-driven C&E, respectively. Increased BMP activity similarly enhances C&E specifically in the ectoderm of intact zebrafish gastrulae, highlighting the in vivo relevance of our findings. Together, these results demonstrate that temporal dynamics of BMP and Nodal morphogen signaling activate distinct morphogenetic programs governing C&E gastrulation movements within individual tissues.
摘要:
脊椎动物身体计划的前后(AP)伸长是由中胚层和神经外胚层的会聚和延伸(C&E)胃内形成运动驱动的,但是C&E的分子调节在组织之间如何或是否有所不同仍然是一个悬而未决的问题。使用斑马鱼外植体模型的AP轴延伸,我们表明神经外胚层和中胚层的C&E可以离体分离,个体组织的形态发生是由不同的形态发生信号动力学引起的。使用BMP和节点信号的精确时间操作,我们确定了一个关键的发育窗口,在此期间,高或低BMP/Nodal比率诱导神经外胚层或中胚层驱动的C&E,分别。增加的BMP活性类似地增强C&E,特别是在完整的斑马鱼胃的外胚层,强调我们的研究结果在体内的相关性。一起,这些结果表明,BMP和Nodal形态发生素信号的时间动力学激活了不同的形态发生程序,从而控制了单个组织内的C&E原肠胚形成运动。
结论:使用斑马鱼胚胎和外植体模型,我们证明,在脊椎动物身体计划形成过程中,形态发生素信号比率的时间动力学可区分组织特异性形态发生程序。