Huotari V, Sormunen R, Lehto V P, Eskelinen S
Biocenter Oulu, University of Oulu, Finland.
Differentiation. 1995 Feb;58(3):205-15. doi: 10.1046/j.1432-0436.1995.5830205.x.
We studied the morphogenesis and the membrane skeleton in the retinal pigment epithelium during chicken embryogenesis and in culture, by using immunofluorescence and electron microscopy. During embryogenesis two distinct membrane skeletal structures were formed, an apical and a basolateral one. The former was seen in the apical surface already in the 10-day-old embryos. It was comprised of ankyrin and alpha-fodrin and showed a codistribution with Na+,K(+)-ATPase and an as yet uncharacterized cadherin-like molecule. The basolateral membrane skeleton was seen in the lateral walls already in the 10-day-old embryos, and later, between the 13th and 17th embryonic days, it also appeared at the basal membrane, coincidentally with the formation of the basal infoldings. It consisted of ankyrin and alpha-fodrin, but did not codistribute with any of the integral membrane proteins studied (Na+,K(+)-ATPase and cadherins). In culture, the retinal pigment epithelial cells retained their polarized morphology. Compared with the situation in vivo, however, there was a distinct translocation of the membrane skeletal components fodrin and ankyrin from the apical surface to the lateral walls, accompanied by a similar redistribution of Na+,K(+)-ATPase and the cadherin-like molecule. The results suggest that (1) there is, in the retinal pigment epithelium, an apical Na+,K(+)-ATPase-membrane skeleton structure stabilized by contacts between the retinal pigment epithelium and the neural retina, possibly mediated by a cadherin-like molecule, and that (2) there is another fodrin/ankyrin-based membrane skeleton in the basolateral walls that is important for the maintenance of the extensive folding of these surface areas.
我们运用免疫荧光和电子显微镜技术，研究了鸡胚胎发育期间及培养过程中视网膜色素上皮的形态发生和膜骨架。在胚胎发育过程中，形成了两种不同的膜骨架结构，一种位于顶端，另一种位于基底外侧。前者在10日龄胚胎的顶端表面即可见到。它由锚蛋白和α - 血影蛋白组成，与Na⁺,K⁺ - ATP酶及一种尚未明确的钙黏蛋白样分子共分布。基底外侧膜骨架在10日龄胚胎的侧壁就已出现，之后，在胚胎发育的第13至17天，它也出现在基底膜，与基底褶皱的形成同时发生。它由锚蛋白和α - 血影蛋白组成，但与所研究的任何整合膜蛋白（Na⁺,K⁺ - ATP酶和钙黏蛋白）都不共分布。在培养过程中，视网膜色素上皮细胞保持其极化形态。然而，与体内情况相比，膜骨架成分血影蛋白和锚蛋白从顶端表面明显转移至侧壁，同时Na⁺,K⁺ - ATP酶和钙黏蛋白样分子也有类似的重新分布。结果表明：（1）在视网膜色素上皮中，存在一种由视网膜色素上皮与神经视网膜之间的接触所稳定的顶端Na⁺,K⁺ - ATP酶 - 膜骨架结构，可能由一种钙黏蛋白样分子介导；（2）在基底外侧壁存在另一种基于血影蛋白/锚蛋白的膜骨架，它对于维持这些表面区域的广泛褶皱很重要。
