2,6-Diaminopurine as a highly potent corrector of UGA nonsense mutations

Carole Trzaska ,Sylvie Rebuffat ,Marie‐Christine Copin ,David Tulasne ,Andreas E Kulozik ,Séverine Amand ,Christine Bailly ,Yuri Motorin ,Pierre–Arthur Moreau ,Éric Adriaenssens ,Thierry Chassat ,David Hannebique ,Hana Benhabiles ,Virginie Marchand ,Catherine Leroy ,Romain Guilbert ,Evelyne Duvernois-Berthet ,Anthony Mouray ,Éric Westhof ,Elisabeth Werkmeister ,Jean‐Michel Saliou ,Fabrice Lejeune

doi:10.1038/s41467-020-15140-z

Abstract

Nonsense mutations cause about 10% of genetic disease cases, and no treatments are available. Nonsense mutations can be corrected by molecules with nonsense mutation readthrough activity. An extract of the mushroom Lepista inversa has recently shown high-efficiency correction of UGA and UAA nonsense mutations. One active constituent of this extract is 2,6-diaminopurine (DAP). In Calu-6 cancer cells, in which TP53 gene has a UGA nonsense mutation, DAP treatment increases p53 level. It also decreases the growth of tumors arising from Calu-6 cells injected into immunodeficient nude mice. DAP acts by interfering with the activity of a tRNA-specific 2′-O-methyltransferase (FTSJ1) responsible for cytosine 34 modification in tRNATrp. Low-toxicity and high-efficiency UGA nonsense mutation correction make DAP a good candidate for the development of treatments for genetic diseases caused by nonsense mutations.

Highlights

Nonsense mutations cause about 10% of genetic disease cases, and no treatments are available
Luciferase activity measurements showed that fractions F13 and F15 corrected the UAA nonsense mutation, while fractions F10, F13, and F15 corrected the UGA nonsense mutation (Fig. 1c)
The combined use of nuclear magnetic resonance (NMR) and mass spectrometry allowed identifying the major component in fractions F13 and F15 as clitocine ((2R,3R,4S,5R)-2-[(6-amino-5nitropyrimidin-4-yl)amino]-5-(hydroxymethyl)oxolane-3,4-diol) (76% and 47%, respectively), known as a potent readthrough molecule[24]

Summary

Introduction

Nonsense mutations cause about 10% of genetic disease cases, and no treatments are available. In Calu-6 cancer cells, in which TP53 gene has a UGA nonsense mutation, DAP treatment increases p53 level. It decreases the growth of tumors arising from Calu-6 cells injected into immunodeficient nude mice. DAP acts by interfering with the activity of a tRNA-specific 2′-O-methyltransferase (FTSJ1) responsible for cytosine 34 modification in tRNATrp. Low-toxicity and high-efficiency UGA nonsense mutation correction make DAP a good candidate for the development of treatments for genetic diseases caused by nonsense mutations. As to date no treatments are available for patients with a genetic disease caused by a nonsense mutation, identifying efficient nonsense mutation correctors is a major public health issue. PTC readthrough has been shown to occur in specific cytoplasmic bodies called readthrough bodies, suggesting that a specific environment may favor PTC readthrough[18]

Methods

Results

Conclusion