Uchiyama H, Komazaki S, Oyama M, Matsui T, Ozeki Y
Department of Environmental Science, Faculty of Science, Yokohama City University, Yokohama, Japan.
Glycobiology. 1997 Dec;7(8):1159-65. doi: 10.1093/glycob/7.8.1159.
Galectins are a family of lectins that recognize beta-D-galactosides independently of calcium ions, and are widely distributed in animals. To characterize a galectin previously purified from oocytes of Rana catesbeiana (American bullfrog), we studied its distribution and localization in several tissues from this frog. Hemagglutination assay and western blotting showed that this lectin is present in many tissues including the liver, skin, kidney, skeletal muscle, and sciatic nerve, but is particularly concentrated in the ovary. Light microscopic immunohistochemistry showed that this lectin is localized in such places as cell-cell junctions, basement membranes, extracellular matrix, or secretory substances in several organs, indicating that this galectin is mainly distributed extracellularly. However, in the ovary, light microscopy showed that this lectin is present in or associated with the yolk platelet. Electron microscopy further revealed that it is localized in the periphery of the yolk platelet (the yolk plasm), but not in the cortical granule. These results indicate that Rana oocytes contain abundant galectin in their yolk platelets in contrast to Xenopus laevis oocytes, which have been found not to contain galectins but other classes of lectins in their yolk platelets and cortical granules.
半乳糖凝集素是一类不依赖钙离子而识别β-D-半乳糖苷的凝集素，广泛分布于动物体内。为了表征一种先前从牛蛙（美国牛蛙）卵母细胞中纯化的半乳糖凝集素，我们研究了它在这种青蛙的几种组织中的分布和定位。血细胞凝集试验和蛋白质免疫印迹表明，这种凝集素存在于包括肝脏、皮肤、肾脏、骨骼肌和坐骨神经在内的许多组织中，但在卵巢中尤其集中。光学显微镜免疫组织化学显示，这种凝集素定位于几个器官中的细胞间连接、基底膜、细胞外基质或分泌物质等部位，表明这种半乳糖凝集素主要分布在细胞外。然而，在卵巢中，光学显微镜显示这种凝集素存在于卵黄小板中或与卵黄小板相关。电子显微镜进一步揭示，它定位于卵黄小板的周边（卵黄质），而不是皮质颗粒中。这些结果表明，与非洲爪蟾卵母细胞不同，牛蛙卵母细胞在其卵黄小板中含有丰富的半乳糖凝集素，非洲爪蟾卵母细胞已被发现在其卵黄小板和皮质颗粒中不含有半乳糖凝集素，而是含有其他类别的凝集素。
