Asymmetric expression in somites of cytotactin and its proteoglycan ligand is correlated with neural crest cell distribution.
Asymmetric expression in somites of cytotactin and its proteoglycan ligand is correlated with neural crest cell distribution.
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DOI：
10.1073/pnas.84.22.7977
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发表时间：
1987-11
影响因子：
11.1
通讯作者：
Seong-Seng Tan;K. L. Crossin;Stanley Hoffman;Gerald M. Edelman
中科院分区：
文献类型：
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作者：
Seong-Seng Tan;K. L. Crossin;Stanley Hoffman;Gerald M. Edelman
脊椎动物神经嵴的发育在模式形成方面提出了一个特别具有挑战性的问题。几项研究表明，一群神经嵴细胞仅穿透体节的吻侧部分的巩膜间充质。在寻找这种模式的分子相关性时，我们观察到细胞趋化素和硫酸软骨素蛋白聚糖这两种相互作用的细胞外基质分子在骨节内显示出特殊的分布。大约在神经嵴细胞侵袭时，细胞趋化素位于巩膜切开器的前半部。蛋白多糖最初扩散到整个骨片，但在细胞趋化素出现和头半部神经嵴细胞侵入后，蛋白多糖仅限于尾半部。这些分布与嵴细胞无关；即使通过神经管手术摘除所有嵴细胞，它们也会按照相同的时间表发生。此外，在组织培养中，体细胞合成了高水平的这两种分子。在体外，嵴细胞在这些分子存在下聚集，细胞迁移测定表明，单独的细胞趋化素和蛋白多糖都不像纤连蛋白那样是嵴细胞迁移的良好基质。然而，与纤连蛋白结合，细胞趋化素或蛋白聚糖仅限制细胞运动，但不能阻止细胞运动。总而言之，这些观察结果支持这样的假设：细胞趋化素和硫酸软骨素蛋白多糖可能通过其位点限制性分布、改变在纤连蛋白等其他底物上迁移的能力以及诱导细胞表面调节的能力，有助于胚胎发生过程中的模式形成。
The development of the vertebrate neural crest presents a particularly challenging problem in pattern formation. Several studies have revealed that a population of neural crest cells penetrates the sclerotomal mesenchyme of the somite only in its rostral half. In a search for molecular correlates of this pattern, we have observed that cytotactin and a chondroitin sulfate proteoglycan, two interactive extracellular matrix molecules, show a specialized distribution within the sclerotome. Cytotactin was localized in the rostral half of the sclerotome at about the time of neural crest cell invasion. The proteoglycan was initially diffuse throughout the sclerotome but became restricted to the caudal half after the appearance of cytotactin and invasion of neural crest cells in the rostral half. These distributions were crest cell-independent; they occurred on the same schedule even when all crest cells were removed by surgical extirpation of the neural tube. Furthermore, in tissue culture, somite cells synthesized high levels of both molecules. In vitro, crest cells rounded up in the presence of these molecules and cell migration assays revealed that neither cytotactin nor proteoglycan alone was as good a substratum for crest cell migration as fibronectin. In combination with fibronectin, however, cytotactin or proteoglycan only restricted cell movement but did not prevent it. Taken together, these observations support the hypothesis that cytotactin and the chondroitin sulfate proteoglycan may contribute to pattern formation during embryogenesis by means of their site-restricted distribution, their ability to alter migration on other substrates such as fibronectin, and their ability to induce cell-surface modulation.