Ex vivo correction of selenoprotein N deficiency in rigid spine muscular dystrophy caused by a mutation in the selenocysteine codon

• Published in: Nucleic acids research Vol. 36; no. 1; pp. 237 - 244
• Main Authors: Rederstorff, M, Allamand, V, Guicheney, P, Gartioux, C, Richard, P, Chaigne, D, Krol, A, Lescure, A
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-01-2008; Oxford Publishing Limited (England)
• Subjects: Biochemistry, Molecular Biology; Cellular Biology; Codon; Codon - chemistry; Codon, Nonsense; Fibroblasts; Fibroblasts - metabolism; HeLa Cells; Humans; Life Sciences; Molecular Biology; Muscle Proteins; Muscle Proteins - biosynthesis; Muscle Proteins - deficiency; Muscle Proteins - genetics; Muscular Atrophy, Spinal; Muscular Atrophy, Spinal - genetics; Muscular Atrophy, Spinal - metabolism; RNA, Transfer, Amino Acid-Specific; RNA, Transfer, Amino Acid-Specific - genetics; Selenocysteine; Selenocysteine - metabolism; Selenoproteins; Selenoproteins - biosynthesis; Selenoproteins - deficiency; Selenoproteins - genetics; Transgenes
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkm1033

Premature termination of translation due to nonsense mutations is a frequent cause of inherited diseases. Therefore, many efforts were invested in the development of strategies or compounds to selectively suppress this default. Selenoproteins are interesting candidates considering the idiosyncrasy of the amino acid selenocysteine (Sec) insertion mechanism. Here, we focused our studies on SEPN1, a selenoprotein gene whose mutations entail genetic disorders resulting in different forms of muscular diseases. Selective correction of a nonsense mutation at the Sec codon (UGA to UAA) was undertaken with a corrector tRNASec that was engineered to harbor a compensatory mutation in the anticodon. We demonstrated that its expression restored synthesis of a full-length selenoprotein N both in HeLa cells and in skin fibroblasts from a patient carrying the mutated Sec codon. Readthrough of the UAA codon was effectively dependent on the Sec insertion machinery, therefore being highly selective for this gene and unlikely to generate off-target effects. In addition, we observed that expression of the corrector tRNASec stabilized the mutated SEPN1 transcript that was otherwise more subject to degradation. In conclusion, our data provide interesting evidence that premature termination of translation due to nonsense mutations is amenable to correction, in the context of the specialized selenoprotein synthesis mechanism.