Modulation of prion protein expression through cryptic splice site manipulation

• Published in: bioRxiv
• Main Authors: Gentile, Juliana E, Corridon, Taylor L, Mortberg, Meredith A, D'Souza, Elston Neil, Whiffin, Nicola, Minikel, Eric Vallabh, Vallabh, Sonia M
• Format: Journal Article
• Language: English
• Published: United States 19.12.2023
• ISSN: 2692-8205; 2692-8205
• DOI: 10.1101/2023.12.19.572439

Lowering expression of prion protein (PrP) is a well-validated therapeutic strategy in prion disease, but additional modalities are urgently needed. In other diseases, small molecules have proven capable of modulating pre-mRNA splicing, sometimes by forcing inclusion of cryptic exons that reduce gene expression. Here, we characterize a cryptic exon located in human 's sole intron and evaluate its potential to reduce PrP expression through incorporation into the 5' untranslated region (5'UTR). This exon is homologous to exon 2 in non-primate species, but contains a start codon that would yield an upstream open reading frame (uORF) with a stop codon prior to a splice site if included in mRNA, potentially downregulating PrP expression through translational repression or nonsense-mediated decay. We establish a minigene transfection system and test a panel of splice site alterations, identifying mutants that reduce PrP expression by as much as 78%. Our findings nominate a new therapeutic target for lowering PrP.