Rickmann M, Fawcett J W, Keynes R J
J Embryol Exp Morphol. 1985 Dec;90:437-55.
We have studied the pathway of migration of neural crest cells through the somites of the developing chick embryo, using the monoclonal antibodies NC-1 and HNK-1 to stain them. Crest cells, as they migrate ventrally from the dorsal aspect of the neural tube, pass through the lateral part of the sclerotome, but only through that part of the sclerotome which lies in the rostral half of each somite. This migration pathway is almost identical to the path which presumptive motor axons take when they grow out from the neural tube shortly after the onset of neural crest migration. In order to see whether the ventral root axons are guided along this pathway by neural crest cells, we surgically excised the neural crest from a series of embryos, and examined the pattern of axon outgrowth approximately 24 h later. In somites which contained no neural crest cells, ventral root axons were still found only in the rostral half of the somite, although axonal growth was slightly delayed. These axons were surrounded by sheath cells, which had presumably migrated out of the neural tube, to a point about 50 micron proximal to the growth cones. With appropriate antibodies we found that the extracellular matrix components fibronectin and laminin are evenly distributed between the rostral and caudal halves of the somite. Neither of these molecules therefore plays a critical role in determining the specific pathway of neural crest cells or motor axons through the rostral half of the somite.
我们利用单克隆抗体NC - 1和HNK - 1对其进行染色，研究了神经嵴细胞在发育中的鸡胚体节中的迁移途径。当神经嵴细胞从神经管背侧向腹侧迁移时，它们穿过了生骨节的外侧部分，但仅穿过了每个体节头侧半部分的生骨节。这种迁移途径几乎与运动轴突在神经嵴迁移开始后不久从神经管长出时所走的路径相同。为了观察腹根轴突是否由神经嵴细胞引导沿着这条途径生长，我们手术切除了一系列胚胎的神经嵴，并在大约24小时后检查轴突生长的模式。在不含神经嵴细胞的体节中，腹根轴突仍仅在体节的头侧半部分被发现，尽管轴突生长略有延迟。这些轴突被鞘细胞包围，鞘细胞大概是从神经管迁移出来的，到达生长锥近端约50微米处。通过适当的抗体，我们发现细胞外基质成分纤连蛋白和层粘连蛋白在体节的头侧和尾侧半部分之间均匀分布。因此，这两种分子在决定神经嵴细胞或运动轴突通过体节头侧半部分的特定途径中都不发挥关键作用。
