Department of Anatomy and Embryology, Centre of Anatomy, University of Göttingen, Germany.
Dev Dyn. 2011 Aug;240(8):1905-16. doi: 10.1002/dvdy.22687.
Formation of the mammalian primitive streak appears to rely on cell proliferation to a minor extent only, but compensating cell movements have not yet been directly observed. This study analyses individual cell migration and proliferation simultaneously, using multiphoton and differential interference contrast time-lapse microscopy of late pregastrulation rabbit blastocysts. Epiblast cells in the posterior gastrula extension area accumulated medially and displayed complex planar movements including U-turns and a novel type of processional cell movement. In the same area metaphase plates tended to be aligned parallel to the anterior-posterior axis, and statistical analysis showed that rotations of metaphase plates causing preferred orientation were near-complete 8 min before anaphase onset; in some cases, rotations were strikingly rapid, achieving up to 45° per min. The mammalian primitive streak appears to be formed initially with its typically minimal anteroposterior elongation by a combination of oriented cell divisions with dedicated planar cell movements.
哺乳动物原肠胚的形成似乎只在很小程度上依赖于细胞增殖，但补偿性细胞运动尚未被直接观察到。本研究使用多光子和相差对比时差显微镜对晚期胚泡期兔胚胎进行分析，同时分析了单个细胞的迁移和增殖。在后原肠胚延伸区的上胚层细胞向中线聚集，并表现出复杂的平面运动，包括 U 形转弯和一种新型的程序性细胞运动。在同一区域，中期板往往与前后轴平行排列，统计分析表明，导致优先取向的中期板旋转在后期起始前 8 分钟接近完全；在某些情况下，旋转速度非常快，每分钟可达 45°。哺乳动物原肠胚的形成最初似乎是通过有向细胞分裂和专用平面细胞运动的组合，以最小的前后延伸方式形成的。
