GLYCOPROTEIN SYNTHESIS AND METABOLISM IN RETINAS

提出的这项研究解决了低聚糖链的作用 视紫红质在盘膜形态发生中的作用有人建议，这些 低聚糖参与细胞间的粘连相互作用 外翻质膜的相对表面，最终形成 闭合式椎间盘的管腔表面。这一假设将通过(1)检验。 通过生物合成防止寡糖与视蛋白的结合 多肽结合部位的修饰，(2)干扰正常 选择性抑制结合低聚糖的结构 寡糖加工酶，(3)与视蛋白竞争 具有外源供应的已知碳水化合物的低聚糖 结构，以及(4)从质膜上去除视蛋白的寡糖 用酶处理表面。每种治疗方法对视网膜的影响 在短期内，体内培养将与对照进行比较 通过监测放射性标记的膜糖蛋白的掺入 前驱体进入新形成的棒材外节膜，使用 生化技术以及光学和电子显微镜 放射自显影。新组装的颗粒的形态和数量 膜将通过电子显微镜进行分析。 对这些盘基本机制的更详细的说明 形态发生将提供对正常的更完整的理解 感光细胞生物学。这可能会为发现 迄今为止未被发现的遗传和代谢缺陷的潜在基因座 它们促进光感受器的选择性发育不全或退化 某些人类视网膜营养不良症。

The research proposed addresses the role of the oligosaccharide chains of rhodopsin in disc membrane morphogenesis. It is proposed that these oligosaccharides participate in adhesional interactions between the closely apposed surfaces of the evaginating plasmalemma which ultimately form the lumenal surfaces of closed discs. The hypothesis will be tested by (1) preventing the attachment of oligosaccharides to opsin by biosynthetic modification of the peptide attachment site, (2) perturbing the normal structure of the attached oligosaccharides by selective inhibition of the oligosaccharide processing enzymes, (3) competing against opsin's oligosaccharides with exogenously supplied carbohydrates of known structure, and (4) removing opsin's oligosaccharides from the plasmalemma surface enzymatically. The effect of each of these treatments on retinas in short-term in vivo cultures will be assessed in comparison with controls by monitoring the incorporation of radiolabeled membrane glycoprotein precursors into newly forming rod outer segment membranes, using biochemical techniques as well as light and electron microscopic autoradiography. The morphology and amount of the newly assembled membranes will be analyzed by electron microscopy. Elucidation of these finer details of the basic mechanisms of disc morphogenesis will provide a more complete understanding of normal photoreceptor cell biology. This may provide clues for discovering heretofore unappreciated potential loci of genetic and metabolic defects which promote the selective dysgenesis or degeneration of photoreceptors in certain human retinal dystrophies.