Colas Jean-François, Schoenwolf Gary C
Department of Neurobiology and Anatomy, University of Utah School of Medicine, 401 MREB (Bldg. 531), 20 North 1900 East, Salt Lake City, UT 84132-3401, USA.
Dev Neurosci. 2003 Sep-Oct;25(5):357-65. doi: 10.1159/000073513.
The formation of the neural tube (neurulation) depends on the physical properties of the cells and tissues both inside and outside the neural plate. One such important physical property is cell adhesion. Theoretical and biological evidence support a role for cell adhesion in neurulation, but few specific cell adhesion molecules have been identified during this process. Ephrin-A5 and Integrin alpha6 are two of the known genes encoding cell adhesion molecules that are likely to be directly involved in neurulation because neural tube defects result when they are knocked out in mice. Yet it remains unclear how they can act on the cell and tissue behaviors of neurulation, because their domains of expression in neurulating tissues have not been reported. We report here the detailed pattern of expression of these two cell adhesion molecules in the chick embryo throughout the stages of neurulation at the mRNA and protein level. We show that Ephrin-A5 and Integrin alpha6 are differentially expressed in the ectoderm, outside and inside the neural plate, respectively, and that they are both restricted to neurulation at cranial (brain) levels. We discuss the potential contribution of this differential expression to the cell adhesion mechanisms involved in cranial neurulation and anencephaly.
神经管的形成（神经胚形成）取决于神经板内外细胞和组织的物理特性。其中一个重要的物理特性就是细胞黏附。理论和生物学证据支持细胞黏附在神经胚形成过程中发挥作用，但在此过程中仅鉴定出少数几种特定的细胞黏附分子。Ephrin - A5和整合素α6是已知的两个编码细胞黏附分子的基因，它们很可能直接参与神经胚形成，因为在小鼠中敲除这两个基因会导致神经管缺陷。然而，目前尚不清楚它们如何作用于神经胚形成过程中的细胞和组织行为，因为尚未有关于它们在神经胚形成组织中的表达域的报道。我们在此报告这两种细胞黏附分子在鸡胚神经胚形成各阶段mRNA和蛋白质水平的详细表达模式。我们发现，Ephrin - A5和整合素α6分别在神经板外的外胚层和神经板内差异表达，并且它们都局限于颅（脑）部水平的神经胚形成过程。我们讨论了这种差异表达对颅部神经胚形成和无脑畸形所涉及的细胞黏附机制的潜在贡献。
