Noden D M
Department of Anatomy, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401.
J Neurobiol. 1993 Feb;24(2):248-61. doi: 10.1002/neu.480240210.
Neural crest cells represent a unique link between axial and peripheral regions of the developing vertebrate head. Although their fates are well catalogued, the issue of their role in spatial organization is less certain. Recent data, particularly on patterns of expression of Hox genes in the hindbrain and crest cells, have raised anew the debate whether a segmental arrangement is the basis for positional specification of craniofacial epithelial and mesenchymal tissues or is but one manifestation of underlying spatial programming processes. The mechanisms of positional specification of sensory neurons derived from the neural crest and placodes are unknown. This review examines the spatial organization of cells and tissues that develop in proximity to sensory neurons; some of these tissues share a common ancestry, others are targets of cranial sensory and motor nerves. All share the necessity of acquiring and expressing site-specific properties in a functionally integrated manner. This integration occurs in part by coordinating patterns of cell migration, as occurs between migrating crest cells and branchial arch myoblasts. Constant rostro-caudal relations are maintained among these precursors as they move dorsoventrally from the hindbrain-paraxial regions to establish branchial arches. During this period the interactions among these and other mesenchymal cells are hierarchical; each cell population differentially integrates its past with cues emanating from new microenvironments. Analyses of tissue interactions indicate that neural crest cells play a dominant role in this scenario.
神经嵴细胞是发育中的脊椎动物头部轴向区域和外周区域之间的独特联系。尽管它们的命运已被详细分类，但它们在空间组织中的作用问题仍不太明确。最近的数据，特别是关于后脑和嵴细胞中Hox基因表达模式的数据，再次引发了一场争论，即节段性排列是颅面上皮和间充质组织位置特异性的基础，还是仅仅是潜在空间编程过程的一种表现。源自神经嵴和基板的感觉神经元的位置特异性机制尚不清楚。这篇综述研究了在感觉神经元附近发育的细胞和组织的空间组织；其中一些组织有着共同的起源，其他组织则是颅神经感觉和运动神经的靶标。所有这些组织都需要以功能整合的方式获得并表达位点特异性特性。这种整合部分是通过协调细胞迁移模式来实现的，就像迁移的嵴细胞和鳃弓成肌细胞之间发生的那样。当这些前体细胞从后脑-轴旁区域向背腹方向移动以形成鳃弓时，它们之间保持着恒定的头-尾关系。在此期间，这些间充质细胞与其他间充质细胞之间的相互作用是分层的；每个细胞群体都以不同的方式将其过去与来自新微环境的信号整合起来。组织相互作用分析表明，在这种情况下神经嵴细胞起着主导作用。
