Electron microscopic immunocytochemistry of interstitial retinol-binding protein in vertebrate retinas.
Electron microscopic immunocytochemistry of interstitial retinol-binding protein in vertebrate retinas.
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发表时间：
1986-05
影响因子：
4.4
通讯作者：
B. Schneider;D. Papermaster;G. Liou;S. Fong;C. Bridges
中科院分区：
文献类型：
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作者：
B. Schneider;D. Papermaster;G. Liou;S. Fong;C. Bridges
间质性视黄醇结合蛋白（Interstitial retinol binding protein，IRBP）是一种可溶性糖蛋白，存在于光感受器间基质（interphotoreceptor matrix，IPM）中，参与视黄醇在视网膜和色素上皮（pigment epithelium，PE）细胞之间的穿梭。作者用电镜免疫细胞化学方法研究了IRBP的分布。Lowicryl K4 M包埋R. pipiens，尖叶木X.用亲和纯化的兔抗牛IRBP、生物素基-羊抗兔F（Ab '）2和抗生物素蛋白-铁蛋白，或用抗生物素蛋白和生物素基-铁蛋白依次标记牛和人视网膜。抗原位于感光细胞间隙，并嵌入PE细胞微绒毛之间的狭窄间隙。PE细胞之间的IRBP渗透被PE连接复合体突然界定。IRBP还观察到在PE细胞的顶端细胞质中的小空泡和在PE细胞吞噬体中含有IRBP周围摄入的杆尖端。IPM被大量但不均匀地标记。抗原通常沿着ROS和COS质膜沉积在一个汇合层中，但有时它分布在大的（约100 μ m）。0.2-微米厚）团块。在牛和人的视网膜中，连接纤毛被高密度的抗原包被，但其质膜周围有未标记的晕。内节顶端质膜沿着连接纤毛排列，也被抗原致密包被。在两种蛙视网膜中，睫状体嵴复合体（PRC）的嵴被抗原包被。在没有四个物种的研究是高尔基体标记本。在牛视网膜，标记的空泡（颗粒）在肌样区发现在非常低的数字（15个空泡在358杆细胞）。两栖类视网膜也只含有少量的肌样空泡标记的抗IRBP。在邻接光感受器间基质的任何细胞中没有抗体结合到细胞内合成位点，表明抗原可能在其从合成细胞释放之前被掩蔽，或者其水平低于检测限。
Interstitial retinol binding protein (IRBP) is a soluble glycoprotein found in the interphotoreceptor matrix (IPM) and implicated in shuttling retinol between retina and pigment epithelium (PE) cells. The authors have studied the distribution of IRBP by EM immunocytochemistry. Thin sections of Lowicryl K4M embedded R. pipiens, X. laevis, bovine and human retinas were labeled sequentially with affinity purified rabbit antibovine IRBP, biotinyl-sheep antirabbit F(Ab')2, and avidin-ferritin, or with avidin and biotinyl-ferritin. Antigen was in the interphotoreceptor space and intercalated into the narrow spaces between PE cell microvilli. IRBP penetration between PE cells was delimited abruptly by the PE junctional complexes. IRBP was also observed in small vacuoles in the apical cytoplasm of PE cells and in PE cell phagosomes that contained IRBP surrounding ingested rod tips. IPM was heavily but inhomogeneously labeled. Antigen was usually deposited along the ROS and COS plasma membrane in a confluent layer, but sometimes it was distributed in large (ca. 0.2-micron thick) clumps. In bovine and human retinas, the connecting cilium was ensheathed by antigen at high density but an unlabeled halo surrounded its plasma membrane. The apical plasma membrane of the inner segment aligned along the connecting cilium was also densely coated by antigen. In both frog retinas, the ridges of the periciliary ridge complex (PRC) were coated with antigen. In none of the four species examined was Golgi labeling present. In bovine retinas, labeled vacuoles (granules) in the myoid region were found in very low numbers (15 vacuoles in 358 rod cells). Amphibian retinas also contained only small numbers of myoid vacuoles labeled by anti-IRBP. Absence of antibody binding to intracellular sites of synthesis in any of the cells that abut the interphotoreceptor matrix suggests that the antigen may be masked prior to its release from the synthetic cell(s) or that its level is below limits of detection.