RPGR Deficiency Results in Retinal Degeneration in Zebrafish

Abstract

Purpose: : X-linked retinitis pigmentosa (XLRP) is one of the most severe forms of human retinal degeneration, as determined by age-of-onset and progression, and accounts for 6-20% of all RP cases. The RP GTPase Regulator (RPGR) gene is mutated in 70-80% of XLRP patients. Over 290 mutations in RPGR have been identified, which can give rise to central or peripheral retinal dystrophies. The function of RPGR is unclear although the N-terminal half of RPGR (exons 2-11) is structurally similar to the regulator of chromosome condensation (RCC1). Here we use zebrafish as a model to investigate RPGR function.

Methods: : Zebrafish RPGR orthologues were predicted by bioinformatic analysis and confirmed by reverse transcriptase polymerase chain reaction (RT-PCR). Zebrafish RPGR expression patterns during development and in adult tissues were examined by RT-PCR and whole-mount in situ hybridisation, while the localisation was studied by immunostaining. Knock-down of zebrafish RPGR was carried out by morpholino injections. The phenotype of the RPGR deficient morphants was analysed using standardized procedures.

Results: : RPGR

Conclusions: : We identified and examined the expression of zebrafish RPGR. We generated a vertebrate model of RPGR insufficiency using antisense methodology in zebrafish, which showedabnormal retinal development andretinal degeneration due to extensive apoptosis. Human RPGR^ORF15 can rescue the zebrafish RPGR-deficient phenotype.

Keywords: retinal degenerations: cell biology • retinal development • pathology: experimental