Allele-specific invalidation of dominant-negative mutations in PRPH2
Central areolar choroidal dystrophy (CACD) is caused by autosomal dominant pathogenic variants in PRPH2, encoding a tetraspanin protein (peripherin-2) present in the photoreceptor outer segments. Whilst some PRHP2 mutations act in via haploinsufficiency, other variants exert their pathogenicity via a dominant-negative mechanism. For the latter group, allele-specific degradation of the mutant transcript is expected to be of therapeutic benefit. Based on preliminary data for one recurrent missense mutation in PRPH2, as well as locus-sequencing data that identified common polymorphisms in cis with the mutation, we have identified a range of therapeutic targets. The PhD student (DC7) aims to identify which of the many PRPH2 mutations act in a dominant-negative manner, and in parallel will realize an allele-specific inhibition of the expression of the mutant protein via antisense oligonucleotides (ASOs). Via VIP (visible immunoprecipitation) assays DC7 will study the ability of mutant peripherin-2 to interact with other peripherin-2 and/or ROM1 proteins. In parallel, ASOs will be designed targeting the mutation and/or variants elsewhere in the gene that are in cis with the pathogenic variant. Allele-specificity and efficacy will first be measured in transfection assays, and later optimized in an established patient-derived RO model.