Calcium-dependent adhesion is necessary for the maintenance of prosomeres.
Calcium-dependent adhesion is necessary for the maintenance of prosomeres.
复制标题
钙依赖性粘附对于前体的维持是必要的。
DOI：
10.1006/dbio.2001.0182
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Fishell,G
中科院分区：
文献类型：
--
作者：
McCarthy,M;Na,E;Neyt,C;Langston,A;Fishell,G
细胞粘附被认为在中枢神经系统节段性组织的建立和维持中起作用。在这里，我们测试了不同类别的粘附分子在前脑分割中的作用。具体而言，我们检查了来自不同前体的祖细胞在选择性维持或去除不同类别的钙依赖性与非依赖性表面分子后在各种脑区域内重新整合和分化的能力。这一分析暗示钙依赖性粘附分子作为维持前体的核心。只有条件，幸免于钙依赖性粘附系统，但消融更一般（钙非依赖性）的粘附系统导致移植后的前体特异性整合。在这类粘附分子的成员中，R-钙粘蛋白在发育过程中表现出惊人的前体表达模式。为了测试这种分子的表达是否足以指导祖细胞整合到表达R-钙粘蛋白的前体，我们使用了逆转录病毒介导的功能获得方法。我们发现，最初从P2原体（一个不表达R-钙粘蛋白的区域）分离的祖细胞，当被迫表达这种分子时，现在可以更容易地整合到R-钙粘蛋白表达区域，如皮质，腹侧丘脑和下丘脑。尽管如此，我们的分析表明，虽然钙依赖性分子能够指导前体特异性整合，但它们不足以诱导祖细胞改变其区域身份。虽然间脑祖细胞从R-钙粘蛋白表达区的前体5可以整合到R-钙粘蛋白表达区的皮质，他们不表达皮质特异性基因Emx 1或端脑特异性基因Bf-1。此外，间脑的祖细胞，整合异位到皮质不坚持出生后，而相同的祖细胞生存和分化时，他们整合到间脑的同源性。我们的研究结果表明，钙依赖性粘附分子作为前体组织的关键介质，但表明它们不足以赋予区域身份。
Cell adhesion has been suggested to function in the establishment and maintenance of the segmental organization of the central nervous system. Here we tested the role of different classes of adhesion molecules in prosencephalic segmentation. Specifically, we examined the ability of progenitors from different prosomeres to reintegrate and differentiate within various brain regions after selective maintenance or removal of different classes of calcium-dependent versus -independent surface molecules. This analysis implicates calcium-dependent adhesion molecules as central to the maintenance of prosomeres. Only conditions that spared calcium-dependent adhesion systems but ablated more general (calcium-independent) adhesion systems resulted in prosomere-specific integration after transplantation. Among the members of this class of adhesion molecules, R-cadherin shows a striking pattern of prosomeric expression during development. To test whether expression of this molecule was sufficient to direct progenitor integration to prosomeres expressing R-cadherin, we used a retroviral-mediated gain-of-function approach. We found that progenitors originally isolated from prosomere P2 (a region which does not express R-cadherin), when forced to express this molecule, can now integrate more readily into R-cadherin-expressing regions, such as the cortex, the ventral thalamus, and the hypothalamus. Nonetheless, our analysis suggests that while calcium-dependent molecules are able to direct prosomere-specific integration, they are not sufficient to induce progenitors to change their regional identity. While diencephalic progenitors from R-cadherin-expressing regions of prosomere 5 could integrate into R-cadherin-expressing regions of the cortex, they did not express the cortex-specific gene Emx1 or the telencephalic-specific gene Bf-1. Furthermore, diencephalic progenitors that integrate heterotopically into the cortex do not persist postnatally, whereas the same progenitors survive and differentiate when they integrate homotopically into the diencephalon. Together our results implicate calcium-dependent adhesion molecules as key mediators of prosomeric organization but suggest that they are not sufficient to bestow regional identities.