title: Probing mechanisms of photoreceptor degeneration in a new mouse model of the common form of autosomal dominant retinitis pigmentosa due to P23H opsin mutations.
abstract: Rhodopsin, the visual pigment mediating vision under dim light, is composed of the apoprotein opsin and the chromophore ligand 11-cis-retinal. A P23H mutation in the opsin gene is one of the most prevalent causes of the human blinding disease, autosomal dominant retinitis pigmentosa. Although P23H cultured cell and transgenic animal models have been developed, there remains controversy over whether they fully mimic the human phenotype; and the exact mechanism by which this mutation leads to photoreceptor cell degeneration remains unknown. By generating P23H opsin knock-in mice, we found that the P23H protein was inadequately glycosylated with levels 1-10% that of wild type opsin. Moreover, the P23H protein failed to accumulate in rod photoreceptor cell endoplasmic reticulum but instead disrupted rod photoreceptor disks. Genetically engineered P23H mice lacking the chromophore showed accelerated photoreceptor cell degeneration. These results indicate that most synthesized P23H protein is degraded, and its retinal cytotoxicity is enhanced by lack of the 11-cis-retinal chromophore during rod outer segment development.
authors.affiliation: Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Sanae
authors.initials: S
authors.lastname: Sakami
authors.forename: Tadao
authors.initials: T
authors.lastname: Maeda
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Bereta
authors.forename: Kiichiro
authors.initials: K
authors.lastname: Okano
authors.forename: Marcin
authors.initials: M
authors.lastname: Golczak
authors.forename: Alexander
authors.initials: A
authors.lastname: Sumaroka
authors.forename: Alejandro J
authors.initials: AJ
authors.lastname: Roman
authors.forename: Artur V
authors.initials: AV
authors.lastname: Cideciyan
authors.forename: Samuel G
authors.initials: SG
authors.lastname: Jacobson
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Palczewski
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D004195:Disease Models, Animal; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D005260:Female; D055879:Gene Knock-In Techniques; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D020125:Mutation, Missense; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism* / Q000648:ultrastructure; D012174:Retinitis Pigmentosa / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D017299:Rod Opsins / Q000235:genetics / Q000378:metabolism*
chemical_list: D017299:Rod Opsins