Tien L F, McLaughlin B J, Cooper N G
Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee, Memphis 38163.
Invest Ophthalmol Vis Sci. 1991 Feb;32(2):319-26.
The apical membranes of retinal pigmented epithelium (RPE) were isolated from adult, normal (LE), and dystrophic (RCS) rats. The proteins of these RPE subfractions were separated through the use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The lectin-binding properties of glycoproteins were examined in western blots through the use of lectin-peroxidase conjugates. No differences were detected between RPE membrane proteins from normal and dystrophic rats in silver-stained gels. However, these two preparations showed significant differences with respect to their binding of the lectins, Lens culinaris (Lentil), Tetragonolobus purpurea (Lotus), and concanavalin A (Con A). In particular, a glycoprotein with a molecular weight of 86 kD in the RPE apical membrane from normal rats bound Lentil, Lotus, and Con A, but in the membrane from dystrophic rats these binding sites were absent or significantly reduced. Another glycoprotein with a molecular weight of 175 kD was recognized by Lotus in the normal membrane preparation but not in the dystrophic RPE membrane preparation. Developmental studies show that these lectin-binding anomalies appear after postnatal day 11 and are, therefore, most likely coincident with eye opening in RCS rats. These results demonstrate that the RPE glycoproteins (86 and 175 kD) are significantly modified in dystrophic rats. The data also confirm previous observations that differences in the oligosaccharide chains, but not the polypeptide chains, of RPE membrane glycoproteins can be detected between normal and dystrophic rats. To the authors' knowledge, this is the first study to correlate developmentally regulated alterations in specific membrane-associated molecules in the RPE of dystrophic rats with the breakdown in phagocytosis that occurs in these rats.(ABSTRACT TRUNCATED AT 250 WORDS)
从成年正常（LE）大鼠和营养不良（RCS）大鼠中分离出视网膜色素上皮（RPE）的顶端膜。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离这些RPE亚组分的蛋白质。在蛋白质印迹中使用凝集素-过氧化物酶偶联物检测糖蛋白的凝集素结合特性。在银染凝胶中，正常和营养不良大鼠的RPE膜蛋白未检测到差异。然而，这两种制剂在与凝集素刀豆（小扁豆）、紫花四角豆（百脉根）和伴刀豆球蛋白A（Con A）的结合方面表现出显著差异。特别是，正常大鼠RPE顶端膜中分子量为86 kD的糖蛋白与刀豆、百脉根和Con A结合，但在营养不良大鼠的膜中，这些结合位点缺失或显著减少。另一种分子量为175 kD的糖蛋白在正常膜制剂中被百脉根识别，但在营养不良的RPE膜制剂中未被识别。发育研究表明，这些凝集素结合异常在出生后第11天之后出现，因此很可能与RCS大鼠睁眼同时发生。这些结果表明，营养不良大鼠的RPE糖蛋白（86和175 kD）有显著改变。数据还证实了先前的观察结果，即正常和营养不良大鼠之间可以检测到RPE膜糖蛋白的寡糖链而非多肽链存在差异。据作者所知，这是第一项将营养不良大鼠RPE中特定膜相关分子的发育调节变化与这些大鼠吞噬作用的破坏相关联的研究。（摘要截短于250字）
