Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, USA.
Invest Ophthalmol Vis Sci. 2012 Jan 25;53(1):361-73. doi: 10.1167/iovs.11-8635.
Prominin-1 expresses in rod and cone photoreceptors. Mutations in the prominin-1 gene cause retinal degeneration in humans. In this study, the authors investigated the expression and subcellular localization of xlProminin-1 protein, the Xenopus laevis ortholog of prominin-1, in rod and cone photoreceptors of this frog.
Antibodies specific for xlProminin-1 were generated. Immunoblotting was used to study the expression and posttranslational processing of xlProminin-1 protein. Immunocytochemical light and electron microscopy and transgenesis were used to study the subcellular distribution of xlProminin-1.
xlProminin-1 is expressed and is subject to posttranslational proteolytic processing in the retina, brain, and kidney. xlProminin-1 is differently expressed and localized in outer segments of rod and cone photoreceptors of X. laevis. Antibodies specific for the N or C termini of xlProminin-1 labeled the open rims of lamellae of cone outer segments (COS) and the open lamellae at the base of rod outer segments (ROS). By contrast, anti-peripherin-2/rds antibody, Xper5A11, labeled the closed rims of cone lamellae adjacent to the ciliary axoneme and the rims of the closed ROS disks. The extent of labeling of the basal ROS by anti-xlProminin-1 antibodies varied with the light cycle in this frog. The entire ROS was also faintly labeled by both antibodies, a result that contrasts with the current notion that prominin-1 localizes only to the basal ROS.
These findings suggest that xlProminin-1 may serve as an anti-fusogenic factor in the regulation of disk morphogenesis and may help to maintain the open lamellar structure of basal ROS and COS disks in X. laevis photoreceptors.
Prominin-1 在视杆和视锥光感受器中表达。Prominin-1 基因的突变会导致人类视网膜变性。在这项研究中，作者研究了 xlProminin-1 蛋白在这种青蛙的视杆和视锥光感受器中的表达和亚细胞定位。
生成了针对 xlProminin-1 的特异性抗体。免疫印迹用于研究 xlProminin-1 蛋白的表达和翻译后加工。免疫细胞化学光镜和电镜以及转基因用于研究 xlProminin-1 的亚细胞分布。
xlProminin-1 在视网膜、大脑和肾脏中表达，并经历翻译后蛋白水解加工。xlProminin-1 在 X. laevis 的视杆和视锥光感受器的外节中表达和定位不同。针对 xlProminin-1 的 N 或 C 末端的特异性抗体标记了圆锥外节（COS）的开放边缘和视杆外节（ROS）底部的开放板层。相比之下，抗外周蛋白-2/rds 抗体 Xper5A11 标记了相邻于纤毛轴突的圆锥板层的封闭边缘和封闭的 ROS 盘的边缘。抗-xlProminin-1 抗体对基底 ROS 的标记程度随这种青蛙的光周期而变化。两种抗体都微弱地标记了整个 ROS，这与 prominin-1 仅定位于基底 ROS 的当前概念形成对比。
这些发现表明，xlProminin-1 可能作为调节盘状形态发生的抗融合因子，并有助于维持 X. laevis 光感受器中基底 ROS 和 COS 盘的开放板层结构。
