Stankova Viktoria, Tsikolia Nikoloz, Viebahn Christoph
Institute of Anatomy and Embryology, University Medical Centre, Georg August University of Göttingen, Göttingen 37079, Germany.
Institute of Anatomy and Embryology, University Medical Centre, Georg August University of Göttingen, Göttingen 37079, Germany
Development. 2015 Jan 1;142(1):92-8. doi: 10.1242/dev.111583.
During animal gastrulation, the specification of the embryonic axes is accompanied by epithelio-mesenchymal transition (EMT), the first major change in cell shape after fertilization. EMT takes place in disparate topographical arrangements, such as the circular blastopore of amphibians, the straight primitive streak of birds and mammals or in intermediate gastrulation forms of other amniotes such as reptiles. Planar cell movements are prime candidates to arrange specific modes of gastrulation but there is no consensus view on their role in different vertebrate classes. Here, we test the impact of interfering with Rho kinase-mediated cell movements on gastrulation topography in blastocysts of the rabbit, which has a flat embryonic disc typical for most mammals. Time-lapse video microscopy, electron microscopy, gene expression and morphometric analyses of the effect of inhibiting ROCK activity showed - besides normal specification of the organizer region - a dose-dependent disruption of primitive streak formation; this disruption resulted in circular, arc-shaped or intermediate forms, reminiscent of those found in amphibians, fishes and reptiles. Our results reveal a crucial role of ROCK-controlled directional cell movements during rabbit primitive streak formation and highlight the possibility that temporal and spatial modulation of cell movements were instrumental for the evolution of gastrulation forms.
在动物原肠胚形成过程中，胚胎轴的特化伴随着上皮-间充质转化（EMT），这是受精后细胞形态的首次重大变化。EMT发生在不同的拓扑结构中，如两栖动物的圆形胚孔、鸟类和哺乳动物的直的原条，或其他羊膜动物（如爬行动物）的中间原肠胚形成形式。平面细胞运动是安排特定原肠胚形成模式的主要候选因素，但对于它们在不同脊椎动物类群中的作用尚无共识。在这里，我们测试了干扰Rho激酶介导的细胞运动对兔囊胚原肠胚形成拓扑结构的影响，兔具有大多数哺乳动物典型的扁平胚胎盘。延时视频显微镜、电子显微镜、基因表达以及对抑制ROCK活性的影响进行的形态计量学分析表明，除了组织者区域的正常特化外，原条形成存在剂量依赖性破坏；这种破坏导致了圆形、弧形或中间形式，让人联想到在两栖动物、鱼类和爬行动物中发现的那些形式。我们的结果揭示了ROCK控制的定向细胞运动在兔原条形成过程中的关键作用，并突出了细胞运动的时空调节对原肠胚形成形式进化有重要作用的可能性。
