Molecular Mechanisms Underlying PRPF31 Genetic Defects in Retinitis Pigmentosa

Abstract

Abstract: : Purpose: The mutations in human PRPF31 gene have been identified in patients with autosomal dominant retinitis pigmentosa(adRP). This experiment is to investigate the molecular mechanisms by which such mutations cause retinal degeneration. Methods:.We examined effects of wild-type and mutant PRPF31 proteins in a primary retinal neuronal culture system. The cells are plated on the the coverslips and incubated either with the culture medium or the medium containing BAX, a apoptotic inhibitor, for different time points. After transfection in wild-type or mutant PRPF31 genes to the primary retinal cells, the cell death pattern has been followed by TUNEL staining. Results: Following the expression of the mutant PRPF31 proteins in retinal neurons, the viability of retinal neurons was significant decreased. The cells expressing mutant PRPF31 showed nuclear morphology characteristic of apoptosis. The cell death induced by mutant PRPF31 was reduced by treatment with a caspase inhibitor. Conclusions: These experiments reveal that mutant PRPF31 proteins induce retinal neuronal death via caspase-mediated pathway. These results support a gain-of-function toxicity of mutant PRPF31 proteins in retinal neurons, suggesting potential therapeutic intervention by removing the mutant proteins instead of simply providing wild-type PRPF31 protein.

Keywords: retinal degenerations: hereditary • cell death/apoptosis • photoreceptors