Segmentation of the vertebrate skull: neural-crest derivation of adult cartilages in the clawed frog, Xenopus laevis
Segmentation of the vertebrate skull: neural-crest derivation of adult cartilages in the clawed frog, Xenopus laevis
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DOI：
10.1093/icb/icn077
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发表时间：
2008-11-01
影响因子：
2.6
通讯作者：
Hanken, James
中科院分区：
文献类型：
--
作者：
Gross, Joshua B.;Hanken, James
我们利用一种新的转基因细胞标记系统来评估无尾两栖类动物头骨变形后软骨的胚胎起源。这些软骨中的许多在变态时重新形成，并且在幼虫骨骼中没有明显的前体。大多数成人软骨来源于下颌或舌骨神经嵴，单独或组合;鳃流神经嵴做出适度的贡献。每一个流也有助于至少一个软骨在中耳或外耳。四种软骨是复合成分，每种软骨都来自至少两种不同的细胞群。相邻神经嵴区域之间的许多边界是隐蔽的，因为它们与解剖学边界不一致。这些命运映射结果揭示的成人颅骨分割系统在重要方面不同于个体发育早期幼虫头骨的分割和颅分割在Alabrootes。最引人注目的是吻反转的神经嵴衍生软骨爪蟾，下颌流衍生的元素部署尾侧的舌骨流，其中占主导地位的前。这种新的模式的吻分割可能是复杂的，双相的生活史，是大多数物种的生活两栖动物，特别是无尾类，其中颅结构显着重新配置在变态的结果。脊椎动物头骨的神经嵴起源并不是一成不变的;相反，颅骨骨骼各个组成部分的胚胎起源在物种之间可能会有很大的差异。
We utilize a novel, transgenic cell-labeling system to assess the embryonic derivation of cartilages in the post-metamorphic skull of anuran amphibians. Many of these cartilages form de novo at metamorphosis and have no obvious precursors within the larval skeleton. Most adult cartilages are derived from mandibular- or hyoid-stream neural crest, either individually or in combination; branchial-stream neural crest makes a modest contribution. Each stream also contributes to at least one cartilage in the middle ear or external ear. Four cartilages are composite elements; each is derived from at least two distinct cell populations. Many boundaries between adjacent neural-crest territories are cryptic insofar as they do not coincide with anatomical boundaries. The system of adult cranial segmentation revealed by these fate-mapping results differs in important respects from both the segmentation of the ontogenetically earlier larval skull and the cranial segmentation in amniotes. Most striking is the rostral inversion of neural-crest-derived cartilages in Xenopus, such that mandibular stream-derived elements are deployed caudal to those derived from the hyoid stream, which predominate anteriorly. This novel pattern of rostral segmentation may be a consequence of the complex, biphasic life history that is characteristic of most species of living amphibians, and especially anurans, in which cranial architecture is significantly reconfigured at metamorphosis. Neural-crest derivation of the vertebrate skull is not invariant; instead, embryonic derivation of individual components of the cranial skeleton may vary widely among species.