Hong Elim, Brewster Rachel
Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA.
Development. 2006 Oct;133(19):3895-905. doi: 10.1242/dev.02560. Epub 2006 Aug 30.
Through the direct analysis of cell behaviors, we address the mechanisms underlying anterior neural tube morphogenesis in the zebrafish and the role of the cell adhesion molecule N-cadherin (N-cad) in this process. We demonstrate that although the mode of neurulation differs at the morphological level between amphibians and teleosts, the underlying cellular mechanisms are conserved. Contrary to previous reports, the zebrafish neural plate is a multi-layered structure, composed of deep and superficial cells that converge medially while undergoing radial intercalation, to form a single cell-layered neural tube. Time-lapse recording of individual cell behaviors reveals that cells are polarized along the mediolateral axis and exhibit protrusive activity. In N-cad mutants, both convergence and intercalation are blocked. Moreover, although N-cad-depleted cells are not defective in their ability to form protrusions, they are unable to maintain them stably. Taken together, these studies uncover key cellular mechanisms underlying neural tube morphogenesis in teleosts, and reveal a role for cadherins in promoting the polarized cell behaviors that underlie cellular rearrangements and shape the vertebrate embryo.
通过对细胞行为的直接分析，我们探讨了斑马鱼前神经管形态发生的潜在机制以及细胞粘附分子N-钙粘蛋白（N-cad）在此过程中的作用。我们证明，尽管两栖动物和硬骨鱼在形态学水平上的神经胚形成模式不同，但其潜在的细胞机制是保守的。与之前的报道相反，斑马鱼神经板是一种多层结构，由深层和表层细胞组成，这些细胞在进行径向插入时向内侧汇聚，形成单细胞层的神经管。对单个细胞行为的延时记录显示，细胞沿内外侧轴极化并表现出突出活动。在N-cad突变体中，汇聚和插入均被阻断。此外，尽管耗尽N-cad的细胞形成突出的能力没有缺陷，但它们无法稳定地维持突出。综上所述，这些研究揭示了硬骨鱼神经管形态发生的关键细胞机制，并揭示了钙粘蛋白在促进极化细胞行为中的作用，这些行为是细胞重排的基础并塑造了脊椎动物胚胎。
