An engineered U1 snRNP redefines SMN1 exon 7 carrying a pathogenic mutation at the splice donor site
Year: 2016
Type: article
Abstract: The human genome has two copies of the Survival Motor Neuron (SMN) gene, SMN1 and SMN2. The absence of SMN1 results in spinal muscular atrophy (SMA), a leading genetic disease among infants and children. SMN2 cannot substitute for SMN1 because of exon 7 skipping. While restoring exon 7 inclusion in SMN2 is a promising approach for SMA therapy, the method has limitations for specific SMA patients carrying a single SMN2 allele. Recently, a severe SMA patient carrying a single SMN2 allele as well as a SMN1 allele with a deleterious G-to-C mutation (G1C) at the splice donor site of intron 7 has been reported. In this study, we show that an engineered U1 small nuclear ribonucleoprotein (eU1 snRNP) with extended base pairing at the 5′ splice site of intron 7 prevents skipping of exon 7 of SMN1 carrying the G1C mutation. We also show that eU1 snRNA promotes expression of the full length SMN protein from the SMN1 allele carrying the G1C mutation. We further demonstrate that eU1 snRNAs annealing to 5′ splice site-like sequences downstream of the canonical intron 7 splice donor site can activate these sites and promote the inclusion of an extended exon 7 from SMN1 carrying the G1C mutation. Such findings provide a novel method for correcting aberrant splicing in SMA.
Authors: Del Rio-Malewski, José Bruno
Language: English
Subfield: Genetics (clinical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W3005537880