Activation of a cryptic 5′ splice site reverses the impact of pathogenic splice site mutations in the spinal muscular atrophy gene

Date
2017-12-01
Authors
Singh, Natalia
Del Rio-Malewski, Jose Bruno
Luo, Diou
Ottesen, Eric
Howell, Matthew
Singh, Ravindra
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Authors
Research Projects
Organizational Units
Biomedical Sciences
Organizational Unit
Journal Issue
Series
Abstract

Spinal muscular atrophy (SMA) is caused by deletions or mutations of the Survival Motor Neuron 1 (SMN1) gene coupled with predominant skipping of SMN2 exon 7. The only approved SMA treatment is an antisense oligonucleotide that targets the intronic splicing silencer N1 (ISS-N1), located downstream of the 5′ splice site (5′ss) of exon 7. Here, we describe a novel approach to exon 7 splicing modulation through activation of a cryptic 5′ss (Cr1). We discovered the activation of Cr1 in transcripts derived from SMN1 that carries a pathogenic G-to-C mutation at the first position (G1C) of intron 7. We show that Cr1-activating engineered U1 snRNAs (eU1s) have the unique ability to reprogram pre-mRNA splicing and restore exon 7 inclusion in SMN1 carrying a broad spectrum of pathogenic mutations at both the 3′ss and 5′ss of the exon 7. Employing a splicing-coupled translation reporter, we demonstrate that mRNAs generated by an eU1-induced activation of Cr1 produce full-length SMN. Our findings underscore a wider role for U1 snRNP in splicing regulation and reveal a novel approach for the restoration of SMN exon 7 inclusion for a potential therapy of SMA.

Description

This article is published as Singh, Natalia N., José Bruno Del Rio-Malewski, Diou Luo, Eric W. Ottesen, Matthew D. Howell, and Ravindra N. Singh. "Activation of a cryptic 5′ splice site reverses the impact of pathogenic splice site mutations in the spinal muscular atrophy gene." Nucleic acids research 45, no. 21 (2017): 12214-12240. doi: 10.1093/nar/gkx824. Posted with permission.

Keywords
Citation
DOI
Collections