Expression of cell adhesion molecules during embryonic induction. III. Development of the otic placode.
Expression of cell adhesion molecules during embryonic induction. III. Development of the otic placode.
复制标题
胚胎诱导过程中细胞粘附分子的表达。
DOI：
10.1016/0012-1606(87)90223-5
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发表时间：
1987
影响因子：
2.7
通讯作者：
Edelman,GM
中科院分区：
文献类型：
--
作者：
Richardson,GP;Crossin,KL;Chuong,CM;Edelman,GM
在胚胎发育期间，内耳从一个胎座发育成一个分化程度很高的结构，在神经和非神经元素之间有明确的边界。为了从胎盘出现的时间来确定这种分化界限的起源，我们用免疫细胞化学方法定位了细胞黏附分子N-CAM、L-CAM和Ng-CAM以及细胞外基质分子细胞肌动蛋白和纤维连接蛋白在鸡胚胎耳蜗内的发育分布。由于耳道胎盘是由含有N-CAM的菱形脑和中胚层诱导的，所以该胎盘同时表达N-CAM和L-CAM。在听泡分化形成听神经节和耳蜗区分化结构的过程中，神经感觉区N-CAM增加，邻近感觉区的听上皮非感觉区L-CAM增加。在随后的发育过程中，N-CAM和L-CAM的差异表达再次在耳蜗皮内的五个形态和功能不同的区域之间形成了明显的边界。这种CAM的表达模式与先前的观察结果一致，即不同结合特异性的初级CAM以两种不同的方式表达，以在所有胚胎诱导部位和进一步细胞分化部位形成边界(K.L.Crossin，C-M)。Chuong和G.M.Edelman，1985，Proc.娜塔莉。阿卡德。SCI。美国，82,6942-6946)。然而，与涉及间充质的诱导部位不同，胎盘只显示含有两个凸轮的上皮丢失其中一个或保持不变的变化。随着感觉区的神经支配发生分化，出现了次级的Ng-CAM。Ng-CAM阳性纤维进入基底乳头和Ng-CAM，基质蛋白Cytoactin以放射状形式出现在上皮内，这与这些分子在轴突运动中的作用是一致的。免疫印迹分析证实了CaM的特性和生化特性，并揭示了N-CAM在内耳形成过程中经历了胚胎到成体的转化。这些研究支持这样的观点，即在参与诱导事件的细胞集体中，CaM以特定的模式表达，并强烈表明细胞对这些模式的调节与边界的形成相关。他们提出的假设是，细胞外基质分子和细胞外基质分子的时空协调表达可能在指导遵循这种边界形成的进一步组织发生事件方面特别重要。
During embryonic development, the inner ear develops from a placode into a richly differentiated structure with defined borders between neural and non-neural elements. In an effort to define the origin of such differentiation boundaries from the time of appearance of the placode, immunocytochemical methods have been used to map the developmental distributions of the cell adhesion molecules, N-CAM, L-CAM, and Ng-CAM, and the extracellular matrix molecules, cytotactin and fibronectin, in the cochlea of the chicken embryo. As the otic placode was induced by the underlying N-CAM-containing rhombencephalon and mesoderm, the placode expressed both N-CAM and L-CAM. During the period when the otic vesicle differentiated to give rise to the acoustic ganglion and to the differentiated structures of the cochlea, N-CAM increased in the innervated sensory regions while L-CAM increased in the non-sensory areas of the auditory epithelium adjacent to the sensory regions. During subsequent development, the differential expression of N-CAM and L-CAM again formed striking borders within the epithelium between the five morphologically and functionally distinct regions of the cochlea. This pattern of CAM expression is consistent with previous observations suggesting that primary CAMs of different binding specificities are expressed in two different modes to form borders at all sites of embryonic induction and at sites of further cytodifferentiation (K. L. Crossin, C-M. Chuong, and G. M. Edelman, 1985,Proc. Natl. Acad. Sci. USA,82,6942–6946). Unlike inductive sites involving mesenchyme, however, the placode showed only changes in which an epithelium containing both CAMs loses one or the other or remains unchanged. As differentiation occurred during innervation of the sensory region, the secondary Ng-CAM appeared. Ng-CAM-positive fibers penetrated into the basilar papilla and Ng-CAM and the matrix protein cytotactin appeared within the epithelium in a radial pattern that was consistent with the previously described roles of these molecules in neurite movement. Immunoblot analyses confirmed the identity and biochemical properties of the CAMs and also revealed that N-CAM underwent embryonic to adult conversion during inner ear formation. These studies support the idea that CAMs are expressed in specific modal patterns in the cell collectives participating in inductive events, and strongly suggest that cellular regulation of these patterns is correlated with border formation. They prompt the hypothesis that the coordinated spatiotemporal expression of CAMs and extracellular matrix molecules may be particularly important in guiding further histogenetic events that follow such border formation.