HHMI, Department of Pediatrics, Molecular Biology Graduate Program, University of Colorado Denver, Aurora, CO 80045, USA.
Dev Biol. 2010 Aug 15;344(2):941-7. doi: 10.1016/j.ydbio.2010.06.010. Epub 2010 Jun 14.
Neurulation, the process of neural tube formation, is a complex morphogenetic event. In the mammalian embryo, an understanding of the dynamic nature of neurulation has been hampered due to its in utero development. Here we use laser point scanning confocal microscopy of a membrane expressed fluorescent protein to visualize the dynamic cell behaviors comprising neural tube closure in the cultured mouse embryo. In particular, we have focused on the final step wherein the neural folds approach one another and seal to form the closed neural tube. Our unexpected findings reveal a mechanism of closure in the midbrain different from the zipper-like process thought to occur more generally. Individual non-neural ectoderm cells on opposing sides of the neural folds undergo a dramatic change in shape to protrude from the epithelial layer and then form intermediate closure points to "button-up" the folds. Cells from the juxtaposed neural folds extend long and short flexible extensions and form bridges across the physical gap of the closing folds. Thus, the combination of live embryo culture with dynamic imaging provides intriguing insight into the cell biological processes that mold embryonic tissues in mammals.
神经胚形成是一个复杂的形态发生事件。在哺乳动物胚胎中，由于其在子宫内的发育，对神经胚形成的动态性质的理解受到了阻碍。在这里，我们使用激光点扫描共聚焦显微镜对膜表达的荧光蛋白进行成像，以可视化包含在培养的小鼠胚胎中神经管闭合的动态细胞行为。特别是，我们集中研究了最后一步，即神经褶彼此靠近并封闭形成封闭的神经管。我们意想不到的发现揭示了中脑闭合的一种机制，与普遍认为发生的拉链状过程不同。神经褶对侧的单个非神经外胚层细胞的形状发生剧烈变化，从上皮层突出，然后形成中间闭合点，将褶皱“扣紧”。来自毗邻神经褶的细胞伸出长而短的灵活延伸，并在闭合褶皱的物理间隙上形成桥。因此，胚胎培养与动态成像的结合为研究哺乳动物胚胎组织形成的细胞生物学过程提供了有趣的见解。
