Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by loss of motor neurons in patients with null mutations in the SMN1 gene. An almost identical SMN2 gene is unable to compensate for this deficiency because a single C-to-T transition at position 6 in exon-7 causes skipping of the exon by a mechanism not yet fully elucidated. We observed that the C-to-T transition in SMN2 creates a putative binding site for the RNA-binding protein Sam68. RNA pull-down assays and UV-crosslink experiments showed that Sam68 binds to this sequence. In vivo splicing assays showed that Sam68 triggers SMN2 exon-7 skipping. Moreover, mutations in the Sam68-binding site of SMN2 or in the RNA-binding domain of Sam68 completely abrogated its effect on exon-7 skipping. Retroviral infection of dominant-negative mutants of Sam68 that interfere with its RNA-binding activity, or with its binding to the splicing repressor hnRNP A1, enhanced exon-7 inclusion in endogenous SMN2 and rescued SMN protein expression in fibroblasts of SMA patients. Our results thus indicate that Sam68 is a novel crucial regulator of SMN2 splicing.
Original language | English |
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Pages (from-to) | 1235-1247 |
Number of pages | 13 |
Journal | EMBO Journal |
Volume | 29 |
Issue number | 7 |
DOIs | |
Publication status | Published - Apr 2010 |
Keywords
- Alternative splicing
- HnRNP A1
- Sam68
- SMA
- SMN2
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Molecular Biology
- Immunology and Microbiology(all)
- Neuroscience(all)