Takata K, Singer S J
Department of Biology, University of California, San Diego, LaJolla 92093.
J Cell Biol. 1988 May;106(5):1757-64. doi: 10.1083/jcb.106.5.1757.
We have used high affinity polyclonal antibodies specific for phosphotyrosine (PTyr) residues to examine the localization in various chick embryonic tissues in situ of PTyr-modified proteins by immunocytochemical methods. During the period from 9 to 21 d of development, most tissues exhibit elevated levels of PTyr-modified proteins as determined by immunoblotting experiments of tissue extracts with the anti-PTyr antibodies (Maher, P. A., and E. B. Pasquale. 1988. J. Cell Biol. 106:1747-1755). By immunofluorescence labeling of semithin frozen sections, the highest concentrations of PTyr immunolabeling in all of the embryonic tissues examined were localized to the membranes of the epithelial and endothelial cells with other cells showing no detectable labeling. These results were confirmed by immunoelectron microscopic labeling, which showed particularly high concentrations of PTyr-modified proteins close to the membranes at the apical junctions. The corresponding adult tissues showed no labeling. It is proposed that these results reflect the molecular basis for the functional plasticity of epithelial and endothelial cell junctions during embryonic development.
我们使用了对磷酸酪氨酸（PTyr）残基具有高亲和力的多克隆抗体，通过免疫细胞化学方法检测PTyr修饰蛋白在各种鸡胚组织中的原位定位。在胚胎发育的第9至21天期间，通过用抗PTyr抗体对组织提取物进行免疫印迹实验（Maher，P. A.，和E. B. Pasquale. 1988. J. Cell Biol. 106:1747 - 1755）确定，大多数组织中PTyr修饰蛋白的水平升高。通过对半薄冰冻切片进行免疫荧光标记，在所检查的所有胚胎组织中，PTyr免疫标记的最高浓度定位于上皮细胞和内皮细胞的膜上，其他细胞未显示可检测到的标记。免疫电子显微镜标记证实了这些结果，该标记显示在顶端连接处靠近膜处PTyr修饰蛋白的浓度特别高。相应的成年组织未显示标记。有人提出，这些结果反映了胚胎发育过程中上皮细胞和内皮细胞连接功能可塑性的分子基础。
