PDF(Pubmed)
Abstract：
Large-scale cell flow characterizes gastrulation in animal development. In amniote gastrulation, particularly in avian gastrula, a bilateral vortex-like counter-rotating cell flow, called \'polonaise movements\', appears along the midline. Here, through experimental manipulations, we addressed relationships between the polonaise movements and morphogenesis of the primitive streak, the earliest midline structure in amniotes. Suppression of the Wnt/planar cell polarity (PCP) signaling pathway maintains the polonaise movements along a deformed primitive streak. Mitotic arrest leads to diminished extension and development of the primitive streak and maintains the early phase of the polonaise movements. Ectopically induced Vg1, an axis-inducing morphogen, generates the polonaise movements, aligned to the induced midline, but disturbs the stereotypical cell flow pattern at the authentic midline. Despite the altered cell flow, induction and extension of the primitive streak are preserved along both authentic and induced midlines. Finally, we show that ectopic axis-inducing morphogen, Vg1, is capable of initiating the polonaise movements without concomitant PS extension under mitotic arrest conditions. These results are consistent with a model wherein primitive streak morphogenesis is required for the maintenance of the polonaise movements, but the polonaise movements are not necessarily responsible for primitive streak morphogenesis. Our data describe a previously undefined relationship between the large-scale cell flow and midline morphogenesis in gastrulation.
摘要：
大规模细胞流动表征动物发育中的原肠胚形成。在羊膜原肠胚形成中，特别是在禽类胃中，双侧涡状反向旋转的细胞流，叫做“波兰运动”，出现在中线。这里,通过实验操作，我们讨论了波兰语运动与原始条纹形态发生之间的关系，羊膜中最早的中线结构。Wnt/平面细胞极性（PCP）信号通路的抑制维持了沿着变形的原始条纹的polonaise运动。有丝分裂的逮捕导致原始条纹的扩展和发展减弱，并维持了波兰运动的早期阶段。异位诱导的Vg1，一种轴诱导形态发生原，产生了波兰的运动，与诱导中线对齐，但扰乱了正中的刻板细胞流动模式。尽管细胞流量改变了，原始条纹的诱导和延伸沿真实和诱导中线保留。最后,我们显示异位轴诱导形态发生原，Vg1能够在有丝分裂停滞条件下启动polonaise运动，而不会伴随PS延伸。这些结果与模型一致，其中需要原始条纹形态发生来维持波兰语运动，但是波兰的运动不一定是原始条纹形态发生的原因。我们的数据描述了原肠胚形成中大规模细胞流动与中线形态发生之间先前未定义的关系。
