scholarly journals Molecular Insights into Determinants of Translational Readthrough and Implications for Nonsense Suppression Approaches

2020 ◽  
Vol 21 (24) ◽  
pp. 9449
Author(s):  
Silvia Lombardi ◽  
Maria Francesca Testa ◽  
Mirko Pinotti ◽  
Alessio Branchini
Keyword(s):  
Therapeutic Strategy ◽  
Low Frequency ◽  
External Factors ◽  
Full Length ◽  
Nonsense Suppression ◽  
Coagulation Disorders ◽  
Nonsense Mutations ◽  
Premature Termination Codons ◽  
Translational Readthrough ◽  
Molecular Determinants

The fidelity of protein synthesis, a process shaped by several mechanisms involving specialized ribosome regions and external factors, ensures the precise reading of sense and stop codons. However, premature termination codons (PTCs) arising from mutations may, at low frequency, be misrecognized and result in PTC suppression, named ribosome readthrough, with production of full-length proteins through the insertion of a subset of amino acids. Since some drugs have been identified as readthrough inducers, this fidelity drawback has been explored as a therapeutic approach in several models of human diseases caused by nonsense mutations. Here, we focus on the mechanisms driving translation in normal and aberrant conditions, the potential fates of mRNA in the presence of a PTC, as well as on the results obtained in the research of efficient readthrough-inducing compounds. In particular, we describe the molecular determinants shaping the outcome of readthrough, namely the nucleotide and protein context, with the latter being pivotal to produce functional full-length proteins. Through the interpretation of experimental and mechanistic findings, mainly obtained in lysosomal and coagulation disorders, we also propose a scenario of potential readthrough-favorable features to achieve relevant rescue profiles, representing the main issue for the potential translatability of readthrough as a therapeutic strategy.

scholarly journals A small molecule that induces translational readthrough of CFTR nonsense mutations by eRF1 depletion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jyoti Sharma ◽  
Ming Du ◽  
Eric Wong ◽  
Venkateshwar Mutyam ◽  
Yao Li ◽  
...  
Keyword(s):  
Protein Function ◽  
Translation Termination ◽  
Nonsense Suppression ◽  
Nonsense Mutations ◽  
Bronchial Epithelial ◽  
Premature Termination Codons ◽  
Translational Readthrough ◽  
Nonsense Mediated Mrna Decay ◽  
Promising Treatment ◽  
And Function

AbstractPremature termination codons (PTCs) prevent translation of a full-length protein and trigger nonsense-mediated mRNA decay (NMD). Nonsense suppression (also termed readthrough) therapy restores protein function by selectively suppressing translation termination at PTCs. Poor efficacy of current readthrough agents prompted us to search for better compounds. An NMD-sensitive NanoLuc readthrough reporter was used to screen 771,345 compounds. Among the 180 compounds identified with readthrough activity, SRI-37240 and its more potent derivative SRI-41315, induce a prolonged pause at stop codons and suppress PTCs associated with cystic fibrosis in immortalized and primary human bronchial epithelial cells, restoring CFTR expression and function. SRI-41315 suppresses PTCs by reducing the abundance of the termination factor eRF1. SRI-41315 also potentiates aminoglycoside-mediated readthrough, leading to synergistic increases in CFTR activity. Combining readthrough agents that target distinct components of the translation machinery is a promising treatment strategy for diseases caused by PTCs.

scholarly journals 2-Guanidino-quinazoline promotes the readthrough of nonsense mutations underlying human genetic diseases

2021 ◽  
Author(s):  
Laure Bidou ◽  
Olivier Bugaud ◽  
Goulven Merer ◽  
Matthieu Coupet ◽  
Isabelle Hatin ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
High Throughput Screening ◽  
Therapeutic Strategy ◽  
Genetic Diseases ◽  
Medical Applications ◽  
Reporter Cell Line ◽  
Reporter Cell ◽  
Nonsense Mutations ◽  
Premature Termination Codons ◽  
Clinical Potential

Premature termination codons (PTCs) account for 10% to 20% of genetic diseases in humans. The gene inactivation resulting from PTC can be counteracted by the use of drugs stimulating PTC readthrough, thereby restoring production of the full-length protein. However, a greater chemical variety of readthrough inducers is required to broaden the medical applications of this therapeutic strategy. In this study, we developed a new reporter cell line and performed high-throughput screening (HTS) to identify potential new readthrough inducers. After three successive assays, we isolated 2-guanidino-quinazoline (TLN468). We assessed the clinical potential of this drug as a potent readthrough inducer on the 40 PTCs most frequently responsible for Duchenne muscular dystrophy. We found that TLN468 was more efficient than gentamicin, and acted on a broader range of sequences, without inducing the readthrough of natural stop codons.

scholarly journals Nonsense suppression of the major rhodopsin gene of Drosophila.

Genetics ◽  
1992 ◽  
Vol 130 (3) ◽  
pp. 585-595 ◽  
Author(s):  
T Washburn ◽  
J E O'Tousa
Keyword(s):  
Deletion Mutant ◽  
Trna Gene ◽  
Site Directed Mutagenesis ◽  
P Element ◽  
Nonsense Suppression ◽  
Nonsense Mutations ◽  
Rhodopsin Gene ◽  
Translational Readthrough ◽  
Mutant Strains ◽  
Nonsense Suppressors

Abstract We placed UAA, UAG and UGA nonsense mutations at two leucine codons, Leu205 and Leu309, in Drosophila's major rhodopsin gene, ninaE, by site-directed mutagenesis, and then created the corresponding mutants by P element-mediated transformation of a ninaE deficiency strain. In the absence of a genetic suppressor, flies harboring any of the nonsense mutations at the 309 site, but not the 205 site, show increased rhodopsin activity. Additionally, all flies with nonsense mutations at either site have better rhabdomere structure than does the ninaE deficiency strain. Construction and analysis of a 3'-deletion mutant of ninaE indicates that translational readthrough accounts for the extra photoreceptor activity of the ninaE309 alleles and that truncated opsins are responsible for the improved rhabdomere structure. The presence of leucine-inserting tRNA nonsense suppressors DtLa Su+ and DtLb Su+ in the mutant strains produced a small increase (less than 0.04%) in functional rhodopsin. The opal (UGA) suppressor derived from the DtLa tRNA gene is more efficient than the amber (UAG) or opal suppressor derived from the DtLb gene, and both DtLa and DtLb derived suppressors are more efficient at site 205 than 309.

scholarly journals Nonsense suppression by near-cognate tRNAs employs alternative base pairing at codon positions 1 and 3

2015 ◽  
Vol 112 (10) ◽  
pp. 3038-3043 ◽  
Author(s):  
Bijoyita Roy ◽  
John D. Leszyk ◽  
David A. Mangus ◽  
Allan Jacobson
Keyword(s):  
Amino Acids ◽  
Full Length ◽  
Nonsense Suppression ◽  
Truncated Protein ◽  
Premature Termination Codons ◽  
Codon Positions ◽  
Nonsense Codons ◽  
Readthrough Protein ◽  
A Site ◽  
Cognate Trna

Premature termination codons (PTCs) in an mRNA ORF inactivate gene function by causing production of a truncated protein and destabilization of the mRNA. Readthrough of a PTC allows ribosomal A-site insertion of a near-cognate tRNA, leading to synthesis of a full-length protein from otherwise defective mRNA. To understand the mechanism of such nonsense suppression, we developed a yeast system that allows purification and sequence analysis of full-length readthrough products arising as a consequence of endogenous readthrough or the compromised termination fidelity attributable to the loss of Upf (up-frameshift) factors, defective release factors, or the presence of the aminoglycoside gentamicin. Unlike classical “wobble” models, our analyses showed that three of four possible near-cognate tRNAs could mispair at position 1 or 3 of nonsense codons and that, irrespective of whether readthrough is endogenous or induced, the same sets of amino acids are inserted. We identified the insertion of Gln, Tyr, and Lys at UAA and UAG, whereas Trp, Arg, and Cys were inserted at UGA, and the frequency of insertion of individual amino acids was distinct for specific nonsense codons and readthrough-inducing agents. Our analysis suggests that the use of genetic or chemical means to increase readthrough does not promote novel or alternative mispairing events; rather, readthrough effectors cause quantitative enhancement of endogenous mistranslation events. Knowledge of the amino acids incorporated during readthrough not only elucidates the decoding process but also may allow predictions of the functionality of readthrough protein products.

scholarly journals Strategies against Nonsense: Oxadiazoles as Translational Readthrough-Inducing Drugs (TRIDs)

2019 ◽  
Vol 20 (13) ◽  
pp. 3329 ◽  
Author(s):  
Ambra Campofelice ◽  
Laura Lentini ◽  
Aldo Di Leonardo ◽  
Raffaella Melfi ◽  
Marco Tutone ◽  
...  
Keyword(s):  
Small Molecules ◽  
Genetic Diseases ◽  
Nonsense Mutations ◽  
New Class ◽  
Premature Termination Codons ◽  
Translational Readthrough ◽  
Action Strategies ◽  
Oxadiazole Derivatives ◽  
Cftr Protein ◽  
Cystic Fibrosis Transmembrane

This review focuses on the use of oxadiazoles as translational readthrough-inducing drugs (TRIDs) to rescue the functional full-length protein expression in mendelian genetic diseases caused by nonsense mutations. These mutations in specific genes generate premature termination codons (PTCs) responsible for the translation of truncated proteins. After a brief introduction on nonsense mutations and their pathological effects, the features of various classes of TRIDs will be described discussing differences or similarities in their mechanisms of action. Strategies to correct the PTCs will be presented, particularly focusing on a new class of Ataluren-like oxadiazole derivatives in comparison to aminoglycosides. Additionally, recent results on the efficiency of new candidate TRIDs in restoring the production of the cystic fibrosis transmembrane regulator (CFTR) protein will be presented. Finally, a prospectus on complementary strategies to enhance the effect of TRIDs will be illustrated together with a conclusive paragraph about perspectives, opportunities, and caveats in developing small molecules as TRIDs.

A global analysis of the reconstitution of PTEN function by translational readthrough of PTEN pathogenic premature termination codons

2021 ◽  
Vol 42 (5) ◽  
pp. 551-566
Author(s):  
Sandra Luna ◽  
Leire Torices ◽  
Janire Mingo ◽  
Laura Amo ◽  
Isabel Rodríguez‐Escudero ◽  
...  
Keyword(s):  
Premature Termination ◽  
Global Analysis ◽  
Premature Termination Codons ◽  
Translational Readthrough

scholarly journals Ribosome readthrough accounts for secreted full-length factor IX in hemophilia B patients with nonsense mutations

2012 ◽  
Vol 33 (9) ◽  
pp. 1373-1376 ◽  
Author(s):  
Mirko Pinotti ◽  
Pierpaolo Caruso ◽  
Alessandro Canella ◽  
Matteo Campioni ◽  
Giuseppe Tagariello ◽  
...  
Keyword(s):  
Factor Ix ◽  
Full Length ◽  
Hemophilia B ◽  
Nonsense Mutations

scholarly journals Screening Readthrough Compounds to Suppress Nonsense Mutations: Possible Application to β-Thalassemia

2020 ◽  
Vol 9 (2) ◽  
pp. 289 ◽  
Author(s):  
Monica Borgatti ◽  
Emiliano Altamura ◽  
Francesca Salvatori ◽  
Elisabetta D’Aversa ◽  
Nicola Altamura
Keyword(s):  
Genetic Disease ◽  
Chelation Therapy ◽  
Translation Termination ◽  
Premature Termination Codon ◽  
Nonsense Suppression ◽  
Current Status ◽  
Nonsense Mutations ◽  
Nonsense Mediated Mrna Decay ◽  
Mrna Destabilization ◽  
Premature Translation Termination

Several types of thalassemia (including β039-thalassemia) are caused by nonsense mutations in genes controlling globin production, leading to premature translation termination and mRNA destabilization mediated by the nonsense mediated mRNA decay. Drugs (for instance, aminoglycosides) can be designed to suppress premature translation termination by inducing readthrough (or nonsense suppression) at the premature termination codon. These findings have introduced new hopes for the development of a pharmacologic approach to cure this genetic disease. In the present review, we first summarize the principle and current status of the chemical relief for the expression of functional proteins from genes otherwise unfruitful for the presence of nonsense mutations. Second, we compare data available on readthrough molecules for β0-thalassemia. The examples reported in the review strongly suggest that ribosomal readthrough should be considered as a therapeutic approach for the treatment of β0-thalassemia caused by nonsense mutations. Concluding, the discovery of molecules, exhibiting the property of inducing β-globin, such as readthrough compounds, is of great interest and represents a hope for several patients, whose survival will depend on the possible use of drugs rendering blood transfusion and chelation therapy unnecessary.

scholarly journals Translational readthrough of GLA nonsense mutations suggests dominant-negative effects exerted by the interaction of wild-type and missense variants

RNA Biology ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 254-263 ◽  
Author(s):  
Silvia Lombardi ◽  
Mattia Ferrarese ◽  
Saverio Marchi ◽  
Paolo Pinton ◽  
Mirko Pinotti ◽  
...  
Keyword(s):  
Dominant Negative ◽  
Wild Type ◽  
Negative Effects ◽  
Nonsense Mutations ◽  
Missense Variants ◽  
Translational Readthrough
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