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Incorporation of unnatural amino acids restores dystrophin expres | 17828
Journal of Genetic Syndromes & Gene Therapy

Journal of Genetic Syndromes & Gene Therapy
Open Access

ISSN: ISSN: 2157-7412

+44 1223 790975

Incorporation of unnatural amino acids restores dystrophin expression in a mouse model of muscular dystrophy


Annual Congress on Rare Diseases & Orphan Drugs

October 26-27, 2016 Chicago, USA

Xia Qing, Jiaqi Lu, Qi Yang, Tianchang Wang, Renyang Xu, Yuyao Tian and Le Tong

Peking University, China

Posters & Accepted Abstracts: J Genet Syndr Gene Ther

Abstract :

Premature termination codon (PTC) disease is accounted for 11% of all genetic diseases, including �?²-thalassemia, cystic fibrosis and Duchenne Muscular Dystrophy (DMD). DMD is a progressive muscular disease affecting 1 out of 3500 male births. This disease is caused by mutations in dystrophin gene. Approximately 10% of mutations causing DMD are non-sense mutations which usually generate a weakly functional truncated dystrophin protein. As a result, myofiber functioning is compromised among patients with DMD. In this study, a genetic code expansion was applied to read-through the non-sense mutation in the dystrophin gene. An evolved orthogonal pair of aminoacyl-tRNA synthetase (aaRS)/tRNA with genetically encoding unnatural amino acid (UAA) selectively enabled the UAA incorporation into the PTC of interested proteins. To further develop a generally applicable UAA system for all three types of non-sense mutations, novel orthogonal tRNAUUA and tRNAUCA were designed to recognize TAA and TGA non-sense mutations. A stable cell line harboring corresponding aaRS/tRNA was built to enhance the UAA incorporation efficiency. During the mRNA translation of dystrophin, the orthogonal tRNA charged with the desired UAA was site-specifically incorporated into the dystrophin protein in response to the non-sense codon TAG. The truncated dystrophin was fully translated by incorporating UAAs into muscle cells manifesting nonsense mutations. UAA plasmids were electroporated and UAAs were injected into the tibialis anterior muscle of mdx mice. Through these procedures, the non-sense mutation was successfully read-through and the fulllength dystrophin protein was synthesized. After UAAs were introduced to dystrophin in UAA-DMD transgenic mice, histological characteristics were improved, dystrophin expression in muscle stem cells was restored and muscle functions were recovered. Our results demonstrated that this approach could be applied to treat PTC disease.

Biography :

Email: xqing@bjmu.edu.cn

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