Prominin-1 Localizes to the Open Rims of Outer Segment Lamellae in Xenopus laevis Rod and Cone Photoreceptors

• Published in: Investigative ophthalmology & visual science Vol. 53; no. 1; pp. 361 - 373
• Main Authors: Han, Zhou, Anderson, David W., Papermaster, David S.
• Format: Journal Article
• Language: English
• Published: United States Association for Research in Vision and Ophthalmology, Inc 01.01.2012
• Subjects: AC133 Antigen; Animals; Animals, Genetically Modified; Antibody Specificity; Antigens, CD - metabolism; Brain - metabolism; Eye Proteins - metabolism; Female; Fluorescent Antibody Technique, Indirect; Glycoproteins - metabolism; Green Fluorescent Proteins - metabolism; Immunoblotting; Kidney - metabolism; Microscopy, Electron; Peptide Fragments; Peptides - metabolism; Protein Processing, Post-Translational; Rabbits; Recombinant Fusion Proteins - metabolism; Retinal Cone Photoreceptor Cells - metabolism; Rod Cell Outer Segment - metabolism; Transgenes; Vision, Ocular - physiology; Xenopus laevis
• ISSN: 1552-5783; 0146-0404; 1552-5783
• 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.