Virtanen I, Wartiovaara J
J Cell Sci. 1976 Nov;22(2):335-44. doi: 10.1242/jcs.22.2.335.
The presence and localization of lectin receptor sites on rat liver cell nuclear and other endomembranes was studied by light and electron microscopy using fluorescein and ferritin-coupled lectin conjugates. Isolated nuclei labelled with fluorescein-conjugated Concanavalin A (Con A) or wheat germ agglutinin (WGA) often showed membrane staining, which sometimes was especially bright on small stretches of the nuclear surface. Unlabelled nuclei and nuclei with a complete ring fluorescence were also seen. The nuclear fluorescence corresponded in intensity to that seen on the surface of isolated rat liver cells. Con A-ferritin particles were seldom detected on the cytoplasmic surface of the intact nuclear envelope. However, at places where the 2 leaflets of the envelope were widely separated or where the outer nuclear membrane was partly torn away, heavy labelling was seen on the cisternal surface of both the inner and outer nuclear membranes. Labelling with Con A-ferritin was also found on the cisternal side of rough endoplasmic reticulum present in the specimens. No labelling was seen on the cytoplasmic surface of mitochondrial outer membrane. The results demonstrate the presence of binding sites for Con A and WGA in nuclei and an asymmetric localization of these sites on the cisternal side of ribosome-carrying endomembranes in rat liver cells.
利用荧光素和铁蛋白偶联的凝集素结合物，通过光学显微镜和电子显微镜研究了大鼠肝细胞细胞核及其他内膜上凝集素受体位点的存在情况和定位。用荧光素偶联的刀豆球蛋白A（Con A）或麦胚凝集素（WGA）标记的分离细胞核常显示膜染色，有时在核表面的小区域染色特别明亮。也可见未标记的细胞核和具有完整环状荧光的细胞核。核荧光强度与分离的大鼠肝细胞表面的荧光强度相当。在完整核膜的细胞质表面很少检测到Con A-铁蛋白颗粒。然而，在核膜的两个小叶广泛分离的地方或外核膜部分撕裂的地方，在内核膜和外核膜的潴泡表面都可见大量标记。在标本中存在的粗面内质网的潴泡侧也发现了Con A-铁蛋白标记。在线粒体外膜的细胞质表面未见到标记。结果表明，大鼠肝细胞的细胞核中存在Con A和WGA的结合位点，且这些位点在携带核糖体的内膜潴泡侧呈不对称定位。
