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Abstract #6016 Published in IGR 2-2
Rom-1 is required for rod photoreceptor viability and the regulation of disk morphogenesis
Clarke G; Goldberg AF; Vidgen D; Collins L; Ploder L; Schwarz L; Molday LL; Rossant J; Szel A; Molday RSNature Genetics 2000; 25: 67-73
The homologous membrane proteins Rom-1 and peripherin-2 are localized to the disc rims of photoreceptor outer segments (OSs), where they associate as tetramers and larger oligomers. Disc rims are thought to be critical for disc morphogenesis, OS renewal and the maintenance of OS structure, but the molecules which regulate these processes are unknown. Although peripherin-2 is known to be required for OS formation (because Prph2-/- mice do not form OSs), and mutations in RDS (the human homologue of Prph2) cause retinal degeneration, the relationship of Rom-1 to these processes is uncertain. Here, the authors show that Rom1-/- mice form OSs in which peripherin-2 homotetramers are localized to the disc rims, indicating that peripherin-2 alone is sufficient for both disc and OS morphogenesis. The discs produced in Rom1-/- mice were large, rod OSs were highly disorganized (a phenotype which largely normalized with age) and rod photoreceptors died slowly by apoptosis. Furthermore, the maximal photoresponse of Rom1-/- rod photoreceptors was lower than that of controls. They conclude that Rom-1 is required for the regulation of disc morphogenesis and the viability of mammalian rod photoreceptors, and that mutations in human ROM1 may cause recessive photoreceptor degeneration.
Dr. G. Clarke, Program in Developmental Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
Classification:
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
