CONSTRUCTION OF EPITHELIOID SHEETS BY TRANSFECTION OF MOUSE SARCOMA-CELLS WITH CDNAS FOR CHICKEN-CELL ADHESION MOLECULES
CONSTRUCTION OF EPITHELIOID SHEETS BY TRANSFECTION OF MOUSE SARCOMA-CELLS WITH CDNAS FOR CHICKEN-CELL ADHESION MOLECULES
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DOI：
10.1073/pnas.85.19.7274
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发表时间：
1988-10-01
影响因子：
11.1
通讯作者：
EDELMAN, GM
中科院分区：
文献类型：
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作者：
MEGE, RM;MATSUZAKI, F;EDELMAN, GM
用肝细胞粘附分子（L-CAM）、神经细胞粘附分子（N-CAM）或两者CAMS的cDNA转染多形性小鼠肉瘤S180细胞。转染细胞在其表面表达适当的CAM，并且当生长至汇合时，表达L-CAM的那些细胞（S180 L细胞）从相邻的梭形或圆形改变为紧密连接的“上皮样”片。用N-CAM的cDNA转染的细胞（S180 N细胞）也在细胞表面上表达这种CAM，并结合含有N-CAM的脑囊泡，但没有表现出上皮样状态的表型变化。在S180 L细胞和双转染（S180 L/N）细胞，L-CAM集中在区域的细胞接触，并与皮质肌动蛋白共分布。在S180 N细胞中，N-CAM均匀分布于细胞表面。当S180 L细胞与S180 L/N细胞共培养时，N-CAM并不集中在S180 L和S180 L/N细胞之间的边界，而是集中在S180 L/N细胞对之间的边界。抗L-CAM的Fab“片段将S180 L或S180 L/N细胞的上皮样片解离成形状类似于未转染细胞的细胞。上皮样片中的细胞呈多边形，但与真正的上皮细胞不同，它们没有基底膜或极性结构，也缺乏紧密连接和桥粒。超微结构检查显示，与未转染的表型细胞相比，上皮样片中的粘附连接和间隙连接大量增加。染料偶联实验表明，差距连接是功能性的。用抗L-CAM Fab“片段处理后，两种连接的表达频率均急剧下降。这些实验提供了支持的优先假说，提出了连接的细胞通过CAM是一个必要的事件，广泛表达的交界处的结构。
Pleiomorphic mouse sarcoma S180 cells were transfected with cDNAs for the liver cell adhesion molecule (L-CAM), the neural cell adhesion molecule (N-CAM), or both CAMS. Transfected cells expressed the appropriate CAMs at their surface and those expressing L-CAM (S180L cells) changed from adjoining spindle or round shapes to a closely linked "epithelioid" sheet when grown to confluence. Cells transfected with cDNA for N-CAM (S180N cells) also expressed this CAM on the cell surfaces and bound brain vesicles containing N-CAM but showed no phenotypic change to an epithelioid state. In S180L cells and doubly transfected (S180L/N) cells, L-CAM was concentrated at regions of cell contact and was codistributed with cortical actin. In S180N cells, N-CAM was uniformly distributed on the cell surface. When S180L cells were cocultured with S180L/N cells, N-CAM was not concentrated at boundaries between the S180L and S180L/N cells but was concentrated at boundaries between pairs of S180L/N cells. Fab'' fragments of anti-L-CAM dissociated the epithelioid sheets of S180L or S180L/N cells into cells with shapes resembling those of untransfected cells. Cells in epithelioid sheets were polygonal in shape but, unlike cells in true epithelia, had no basement membrane or polar structure; they also lacked tight junctions and desmosomes. Ultrastructural examination showed that, in contrast to the untransfected phenotype cells in epithelioid sheets had large increases in adherens junctions and gap junctions. Dye coupling experiments indicated that the gap junctions were functional. The frequency of expression of both kinds of junctions was sharply decreased by treatment with anti-L-CAM Fab'' fragments. These experiments provide support for the precedence hypothesis, which proposes that the linkage of cells by means of CAMs is a necessary event for the extensive expression of junctional structures.