爪蟾胚胎内胚层发育中细胞间连接通讯能力的广泛增强(英文)

本研究以羧基荧光素为示踪物,发现在爪蟾胚胎内胚层大多数细胞之间,这种分子量为376 D的染料的转移,只有到原肠胚末期后才能测出,在此之前,这些细胞之间仅有电耦联存在。观察表明,这一差异不可能单由于细胞分裂体积减小所致,它反映了在原肠胚末期细胞间连接通讯能力由低水平到高水平的转变,是细胞的这一通讯能力发育的结果。这个转变与已知的两栖类内胚层细胞分化区域模式在神经胚早中期的建立在时间上相衔接,因此它是否是后者的必要条件值得进一步查明。在早期囊胚及以后割离的植物性半球的内胚层细胞中,或在中囊胚期之后割离再由单细胞重新聚合成的小细胞团中,其细胞间普遍出现羧基荧光素转移的时间与这些细胞在在体条件下的一致,说明其细胞间连接通讯能力的发育在这样的离体标本中能完全自主地进行。这些标本可以代替整体标本用来方便地测定该转变出现的时间。这种测定对研究各种因素对细胞间连接通讯能力发育的影响具有重要意义。

AN EXTENSIVE INCREASE OF JUNCTIONAL COMMUNICATION CAPACITY IN ENDODERM DEVELOPMENT OF THE XENOPUS EMBRYO

The present result shows that in blastulaand gastrula stages although endoderm cellsof the Xenopus embryo may be electricallycoupled with each other,most of them cannot detectably transfer the 376 dalton mole-cular weight tracer,the carboxyfluorescein,to their contiguous neighbor cells.They be-come capable of such junctional dye transferat the end of gastrulation.This transitionreflects temporally well ordered developmentof junctional communication capacity fromlow to high level,which may be related tothe developmental program of endodermalcellular differentiation.The time course ofthis transition provides a measure for studyof the effects of various factors on the deve-lopment of junctional communication capa-city in this embryo.