Jacobson A G
Department of Zoology, University of Texas at Austin 78712-1064.
Ciba Found Symp. 1994;181:6-21; discussion 21-4. doi: 10.1002/9780470514559.ch2.
How does cell behaviour accomplish neurulation in amphibian embryos? During neurulation, the neural plate (while preserving the same volume) doubles its length, triples its thickness, narrows 10-fold, greatly decreases its surface and rolls into a tube. Cells that compose the neural plate produce these changes in three ways. They change shape, change neighbours and attempt to crawl beneath the contiguous epidermis. Plate width, length and area are decreased and the plate thickens when apical surfaces of plate cells contract radially, but plate length increases and width is further decreased when cells reposition themselves and collect along plate boundaries. Contraction of the apical surfaces of plate cells also helps roll the plate into a tube. Poisson buckling resulting from elongation of plate borders may contribute bending forces that help tube formation. The main folding force in tube formation is a rolling moment toward the midline produced by neural plate cells attempting to crawl beneath the contiguous epidermis. Experiments, observations and computer simulations support these assertions, reveal the organization of cell behaviour and implicate contraction of actin filaments as the main source of the necessary forces.
在两栖类胚胎中，细胞行为是如何实现神经胚形成的？在神经胚形成过程中，神经板（在保持体积不变的情况下）长度翻倍，厚度增至三倍，宽度缩小至十分之一，表面积大幅减小并卷成管状。构成神经板的细胞通过三种方式产生这些变化。它们改变形状、更换相邻细胞，并试图爬到相邻表皮下方。当神经板细胞的顶端表面径向收缩时，板的宽度、长度和面积减小，板变厚；但当细胞重新定位并沿板边界聚集时，板的长度增加而宽度进一步减小。板细胞顶端表面的收缩也有助于将板卷成管状。板边界伸长导致的泊松屈曲可能会产生有助于形成管状的弯曲力。管状形成中的主要折叠力是神经板细胞试图爬到相邻表皮下方时产生的朝向中线的滚动力矩。实验、观察和计算机模拟支持了这些论断，揭示了细胞行为的组织方式，并表明肌动蛋白丝的收缩是必要力的主要来源。
