An ultrastructural analysis of cell and matrix differentiation during early limb development in Xenopus laevis.
An ultrastructural analysis of cell and matrix differentiation during early limb development in Xenopus laevis.
复制标题
非洲爪蟾早期肢体发育过程中细胞和基质分化的超微结构分析。
DOI：
10.1016/0012-1606(74)90164-x
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发表时间：
1974
影响因子：
2.7
通讯作者：
J. G. Bluemink
中科院分区：
文献类型：
--
作者：
R. O. Kelley;J. G. Bluemink
在超微结构水平上对非洲爪哇后肢早期发育(44-48期)进行了分析，重点分析了细胞外基质成分的分化和细胞间的接触。到第44-45阶段，间充质与预期的芽上皮被上皮下室(光板)、连续的基板和几层胶原蛋白(基底板)中的大量真皮颗粒分开。两性磷脂的三复合体稳定化研究表明，每个副真皮颗粒由几个膜状层(电子透射带25-30？；电子致密带20-40？)组成，通常平行于相邻上皮细胞的基面。胶原蛋白纤维由直径为35？的细丝相互连接，这些细丝染有钌红。上皮细胞表面有连接复合体，相对细胞膜有大量桥粒，基面有半桥粒。间充质细胞主要表现为紧密接触(100-150°间隔)，在其表面的不同区域很少有灶性紧密连接。到第47-48阶段，芽上皮下没有副真皮颗粒，基底层中的胶原层失去了丝状交联素。间充质细胞的丝状足细胞穿透松散的基质并与基底板相邻。半桥粒在表皮的基面消失，紧邻上皮的间充质细胞在其侧缘显示局灶性紧密连接和缝隙连接。这些结构变化可能在早期肢体发育的上皮间充质相互作用中起重要作用。定向胶原层的降解允许间充质细胞表面(丝足)与表面相关的上皮细胞产物(组织成基底板)直接结合。间充质中细胞间离子和代谢物运输的结构通路的发展可能协调肢体形态发生的特异性事件。
Early development of the hind limb ofXenopus(stages 44–48) has been analyzed at the level of ultrastructure with emphasis on differentiation of extracellular matrix components and intercellular contacts. By stages 44–45, mesenchyme is separated from prospective bud epithelium by numerous adepidermal granules in a subepithelial compartment (the lamina lucida), a continuous basal lamina and several layers of collagen (the basement lamella). Tricomplex stabilization of amphoteric phospholipid demonstrates that each adepidermal granule consists of several membranelike layers (electron-lucent band 25–30 Å; electron-dense band 20–40 Å), which are usually parallel to the basal surface of adjacent epithelial cells. Collagen fibrils are interconnected by filaments (35 Å in diameter) which stain with ruthenium red. Epithelial cells possess junctional complexes at their superficial borders, numerous desmosomes at apposing cell membranes and hemidesmosomes at their basal surface. Mesenchymal cells predominantly exhibit close contacts (100–150 Å separation) with few focal tight junctions at various areas of their surface. By stages 47–48, adepidermal granules are absent beneath bud epithelium and layers of collagen in the basement lamella lose filamentous cross-linking elements. Filopodia of mesenchymal cells penetrate the disorganized matrix and abut the basal lamina. Hemidesmosomes disappear at the basal surface of the epidermis and mesenchymal cells immediately subjacent to epithelium exhibit focal tight junctions and gap junctions at their lateral borders. These structural changes may be instrumental in the epitheliomesenchymal interactions of early limb development. Degradation of oriented collagenous lamellae permits direct association of mesenchymal cell surfaces (filopodia) with surface-associated products of epithelial cells (organized into the basal lamina). Development of structural pathways for intercellular ion and metabolite transport in mesenchyme may coordinate events specific to limb morphogenesis.