Induction of Translational Readthrough across the Thalassemia-Causing Premature Stop Codon in β-Globin-Encoding mRNA.

Abstract

Nonsense mutations that result in premature stop codons in the HBB gene cause β-thalassemia. This disease is characterized by a reduced hemoglobin level due to the lack of β-globin. Compounds that induce translational readthrough across the thalassemia-causing premature stop codon will have therapeutic benefits. Currently available molecules that induce translational readthrough lack specificity, and some of them show toxicity after prolonged use. In this study, we have developed an oligonucleotide-based approach to induce translational readthrough across the thalassemia-causing premature stop codon. Oligonucleotides that target HBB mRNA downstream of the premature stop codon could induce translational readthrough, generating a full-length β-globin protein. We show this effect using fluorescence- and luminescence-based readthrough assays and by Western blot. Remarkably, the amount of oligonucleotide-induced translational readthrough product is comparable to that of the protein generated by normal translation when there was no premature stop codon. Thus, these oligonucleotides, with certain modifications, have the potential to be used as drugs for the treatment of β-thalassemia. Also, this strategy can be extended to treat other genetic diseases caused by premature stop codons.