Jeffery William R, Strickler Allen G, Yamamoto Yoshiyuki
Department of Biology, University of Maryland, College Park, Maryland 20742, USA.
Nature. 2004 Oct 7;431(7009):696-9. doi: 10.1038/nature02975.
The neural crest, a source of many different cell types in vertebrate embryos, has not been identified in other chordates. Current opinion therefore holds that neural crest cells were a vertebrate innovation. Here we describe a migratory cell population resembling neural crest cells in the ascidian urochordate Ecteinascidia turbinata. Labelling of embryos and larvae with the vital lipophilic dye DiI enabled us to detect cells that emerge from the neural tube, migrate into the body wall and siphon primordia, and subsequently differentiate as pigment cells. These cells express HNK-1 antigen and Zic gene markers of vertebrate neural crest cells. The results suggest that migratory cells with some of the features of neural crest cells are present in the urochordates. Thus, we propose a hypothesis for neural crest evolution beginning with the release of migratory cells from the CNS to produce body pigmentation in the common ancestor of the urochordates and vertebrates. These cells may have gained additional functions or were joined by other cell types to generate the variety of derivatives typical of the vertebrate neural crest.
神经嵴是脊椎动物胚胎中多种不同细胞类型的来源，在其他脊索动物中尚未被发现。因此，目前的观点认为神经嵴细胞是脊椎动物的一项创新。在此，我们描述了一种在海鞘尾索动物 turbinata 中类似神经嵴细胞的迁移细胞群体。用活性亲脂性染料 DiI 对胚胎和幼虫进行标记，使我们能够检测到从神经管中出现、迁移到体壁和虹吸管原基中，并随后分化为色素细胞的细胞。这些细胞表达脊椎动物神经嵴细胞的 HNK-1 抗原和 Zic 基因标记。结果表明，尾索动物中存在具有一些神经嵴细胞特征的迁移细胞。因此，我们提出了一个关于神经嵴进化的假说，即从神经管释放迁移细胞开始，在尾索动物和脊椎动物的共同祖先中产生身体色素沉着。这些细胞可能获得了额外的功能，或者与其他细胞类型结合，从而产生了脊椎动物神经嵴特有的多种衍生物。
