Ataluren and aminoglycosides stimulate read-through of nonsense codons by orthogonal mechanisms
| Autor: | Hong Li, Barry S. Cooperman, Martin Y. Ng, Mikel D. Ghelfi, Yale E. Goldman |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Cystic Fibrosis
read-through Nonsense mutation Peptide Chain Elongation Translational Biochemistry G418 chemistry.chemical_compound Saccharomyces Eukaryotic translation RNA Transfer nonsense suppression Protein biosynthesis Animals TRID Gene Protein Synthesis Inhibitors Oxadiazoles Multidisciplinary ataluren Biological Sciences Stop codon Ataluren Cell biology Muscular Dystrophy Duchenne Aminoglycosides chemistry Codon Nonsense Protein Biosynthesis Transfer RNA Codon Terminator Artemia Release factor Ribosomes |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Significance Nonsense mutations giving rise to premature stop codons (PSCs) cause many diseases, creating the need to develop safe and effective translational read-through–inducing drugs (TRIDs). The current best-characterized TRIDs are ataluren and aminoglycosides. Only ataluren has been approved for clinical use, albeit in a limited context. Here, we provide rate measurements of elementary steps in a single eukaryotic translation elongation cycle, allowing us to demonstrate that ataluren and the aminoglycoside G418 employ orthogonal mechanisms in stimulating PSC read-through: ataluren by inhibiting release factor-dependent termination of protein synthesis and G418 by increasing functional near-cognate transfer RNA mispairing, which permits continuation of synthesis. We conclude that development of new TRIDs combatting PSC diseases should prioritize those directed toward inhibiting termination. During protein synthesis, nonsense mutations, resulting in premature stop codons (PSCs), produce truncated, inactive protein products. Such defective gene products give rise to many diseases, including cystic fibrosis, Duchenne muscular dystrophy (DMD), and some cancers. Small molecule nonsense suppressors, known as TRIDs (translational read-through–inducing drugs), stimulate stop codon read-through. The best characterized TRIDs are ataluren, which has been approved by the European Medicines Agency for the treatment of DMD, and G418, a structurally dissimilar aminoglycoside. Previously [1], we applied a highly purified in vitro eukaryotic translation system to demonstrate that both aminoglycosides like G418 and more hydrophobic molecules like ataluren stimulate read-through by direct interaction with the cell’s protein synthesis machinery. Our results suggested that they might do so by different mechanisms. Here, we pursue this suggestion through a more-detailed investigation of ataluren and G418 effects on read-through. We find that ataluren stimulation of read-through derives exclusively from its ability to inhibit release factor activity. In contrast, G418 increases functional near-cognate tRNA mispairing with a PSC, resulting from binding to its tight site on the ribosome, with little if any effect on release factor activity. The low toxicity of ataluren suggests that development of new TRIDs exclusively directed toward inhibiting termination should be a priority in combatting PSC diseases. Our results also provide rate measurements of some of the elementary steps during the eukaryotic translation elongation cycle, allowing us to determine how these rates are modified when cognate tRNA is replaced by near-cognate tRNA ± TRIDs. |
| Databáze: | OpenAIRE |
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