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Wittenstein A, Caspi M, Rippin I, Elroy-Stein O, Eldar-Finkelman H, Thoms S, Rosin-Arbesfeld R. Nonsense mutation suppression is enhanced by targeting different stages of the protein synthesis process. PLoS Biol 2023; 21:e3002355. [PMID: 37943958 PMCID: PMC10684085 DOI: 10.1371/journal.pbio.3002355] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/28/2023] [Accepted: 09/29/2023] [Indexed: 11/12/2023] Open
Abstract
The introduction of premature termination codons (PTCs), as a result of splicing defects, insertions, deletions, or point mutations (also termed nonsense mutations), lead to numerous genetic diseases, ranging from rare neuro-metabolic disorders to relatively common inheritable cancer syndromes and muscular dystrophies. Over the years, a large number of studies have demonstrated that certain antibiotics and other synthetic molecules can act as PTC suppressors by inducing readthrough of nonsense mutations, thereby restoring the expression of full-length proteins. Unfortunately, most PTC readthrough-inducing agents are toxic, have limited effects, and cannot be used for therapeutic purposes. Thus, further efforts are required to improve the clinical outcome of nonsense mutation suppressors. Here, by focusing on enhancing readthrough of pathogenic nonsense mutations in the adenomatous polyposis coli (APC) tumor suppressor gene, we show that disturbing the protein translation initiation complex, as well as targeting other stages of the protein translation machinery, enhances both antibiotic and non-antibiotic-mediated readthrough of nonsense mutations. These findings strongly increase our understanding of the mechanisms involved in nonsense mutation readthrough and facilitate the development of novel therapeutic targets for nonsense suppression to restore protein expression from a large variety of disease-causing mutated transcripts.
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Affiliation(s)
- Amnon Wittenstein
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Michal Caspi
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ido Rippin
- The Department of Human Molecular Genetics & Biochemistry School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Orna Elroy-Stein
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Hagit Eldar-Finkelman
- The Department of Human Molecular Genetics & Biochemistry School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sven Thoms
- Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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2
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Majumdar S, Emmerich A, Krakovka S, Mandava CS, Svärd SG, Sanyal S. Insights into translocation mechanism and ribosome evolution from cryo-EM structures of translocation intermediates of Giardia intestinalis. Nucleic Acids Res 2023; 51:3436-3451. [PMID: 36912103 PMCID: PMC10123126 DOI: 10.1093/nar/gkad176] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 02/06/2023] [Accepted: 02/24/2023] [Indexed: 03/14/2023] Open
Abstract
Giardia intestinalis is a protozoan parasite that causes diarrhea in humans. Using single-particle cryo-electron microscopy, we have determined high-resolution structures of six naturally populated translocation intermediates, from ribosomes isolated directly from actively growing Giardia cells. The highly compact and uniquely GC-rich Giardia ribosomes possess eukaryotic rRNAs and ribosomal proteins, but retain some bacterial features. The translocation intermediates, with naturally bound tRNAs and eukaryotic elongation factor 2 (eEF2), display characteristic ribosomal intersubunit rotation and small subunit's head swiveling-universal for translocation. In addition, we observe the eukaryote-specific 'subunit rolling' dynamics, albeit with limited features. Finally, the eEF2·GDP state features a uniquely positioned 'leaving phosphate (Pi)' that proposes hitherto unknown molecular events of Pi and eEF2 release from the ribosome at the final stage of translocation. In summary, our study elucidates the mechanism of translocation in the protists and illustrates evolution of the translation machinery from bacteria to eukaryotes from both the structural and mechanistic perspectives.
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Affiliation(s)
- Soneya Majumdar
- Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Andrew Emmerich
- Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Sascha Krakovka
- Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Chandra Sekhar Mandava
- Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Suparna Sanyal
- Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
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3
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Recoding of Nonsense Mutation as a Pharmacological Strategy. Biomedicines 2023; 11:biomedicines11030659. [PMID: 36979640 PMCID: PMC10044939 DOI: 10.3390/biomedicines11030659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Approximately 11% of genetic human diseases are caused by nonsense mutations that introduce a premature termination codon (PTC) into the coding sequence. The PTC results in the production of a potentially harmful shortened polypeptide and activation of a nonsense-mediated decay (NMD) pathway. The NMD pathway reduces the burden of unproductive protein synthesis by lowering the level of PTC mRNA. There is an endogenous rescue mechanism that produces a full-length protein from a PTC mRNA. Nonsense suppression therapies aim to increase readthrough, suppress NMD, or are a combination of both strategies. Therefore, treatment with translational readthrough-inducing drugs (TRIDs) and NMD inhibitors may increase the effectiveness of PTC suppression. Here we discuss the mechanism of PTC readthrough and the development of novel approaches to PTC suppression. We also discuss the toxicity and bioavailability of therapeutics used to stimulate PTC readthrough.
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4
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Veerabhadrappa B, Sj S, Rao NN, Dyavaiah M. Loss of tRNA methyltransferase 9 and DNA damage response genes in yeast confers sensitivity to aminoglycosides. FEBS Lett 2023; 597:1149-1163. [PMID: 36708127 DOI: 10.1002/1873-3468.14591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/05/2023] [Accepted: 01/15/2023] [Indexed: 01/29/2023]
Abstract
tRNA methyltransferase 9 (Trm9)-catalysed tRNA modifications have been shown to translationally enhance the DNA damage response (DDR). Here, we show that Saccharomyces cerevisiae trm9Δ, distinct DNA repair and spindle assembly checkpoint (SAC) mutants are differentially sensitive to the aminoglycosides tobramycin, gentamicin and amikacin, indicating DDR and SAC activation might rely on translation fidelity, under aminoglycoside stress. Further, we report that the DNA damage induced by aminoglycosides in the base excision repair mutants ogg1Δ and apn1Δ is mediated by reactive oxygen species, which induce the DNA adduct 8-hydroxy deoxyguanosine. Finally, the synergistic effect of tobramycin and the DNA-damaging agent bleomycin to sensitize trm9Δ and the DDR mutants mlh1Δ, rad51Δ, mre11Δ and sgs1Δ at significantly lower concentrations compared with wild-type suggests that cells with tRNA modification dysregulation and DNA repair gene defects can be selectively sensitized using a combination of translation inhibitors and DNA-damaging agents.
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Affiliation(s)
- Bhavana Veerabhadrappa
- Department of Biotechnology, R V College of Engineering - Visvesvaraya Technological University, Bengaluru, Karnataka, India.,Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - Sudharshan Sj
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - Nagashree N Rao
- Department of Biotechnology, R V College of Engineering - Visvesvaraya Technological University, Bengaluru, Karnataka, India
| | - Madhu Dyavaiah
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Pondicherry, India
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5
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Palomar-Siles M, Heldin A, Zhang M, Strandgren C, Yurevych V, van Dinter JT, Engels SAG, Hofman DA, Öhlin S, Meineke B, Bykov VJN, van Heesch S, Wiman KG. Translational readthrough of nonsense mutant TP53 by mRNA incorporation of 5-Fluorouridine. Cell Death Dis 2022; 13:997. [PMID: 36433934 PMCID: PMC9700717 DOI: 10.1038/s41419-022-05431-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 11/27/2022]
Abstract
TP53 nonsense mutations in cancer produce truncated inactive p53 protein. We show that 5-FU metabolite 5-Fluorouridine (FUr) induces full-length p53 in human tumor cells carrying R213X nonsense mutant TP53. Ribosome profiling visualized translational readthrough at the R213X premature stop codon and demonstrated that FUr-induced readthrough is less permissive for canonical stop codon readthrough compared to aminoglycoside G418. FUr is incorporated into mRNA and can potentially base-pair with guanine, allowing insertion of Arg tRNA at the TP53 R213X UGA premature stop codon and translation of full-length wild-type p53. We confirmed that full-length p53 rescued by FUr triggers tumor cell death by apoptosis. FUr also restored full-length p53 in TP53 R213X mutant human tumor xenografts in vivo. Thus, we demonstrate a novel strategy for therapeutic rescue of nonsense mutant TP53 and suggest that FUr should be explored for treatment of patients with TP53 nonsense mutant tumors.
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Affiliation(s)
- Mireia Palomar-Siles
- grid.4714.60000 0004 1937 0626Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Angelos Heldin
- grid.4714.60000 0004 1937 0626Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Meiqiongzi Zhang
- grid.4714.60000 0004 1937 0626Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Charlotte Strandgren
- grid.4714.60000 0004 1937 0626Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Viktor Yurevych
- grid.487647.ePrincess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Jip T. van Dinter
- grid.487647.ePrincess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Sem A. G. Engels
- grid.487647.ePrincess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Damon A. Hofman
- grid.487647.ePrincess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Susanne Öhlin
- grid.4714.60000 0004 1937 0626Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Birthe Meineke
- grid.4714.60000 0004 1937 0626Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Vladimir J. N. Bykov
- grid.4714.60000 0004 1937 0626Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Sebastiaan van Heesch
- grid.487647.ePrincess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Klas G. Wiman
- grid.4714.60000 0004 1937 0626Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
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Lombardi S, Testa MF, Pinotti M, Branchini A. Translation termination codons in protein synthesis and disease. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 132:1-48. [PMID: 36088072 DOI: 10.1016/bs.apcsb.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fidelity of protein synthesis, a process shaped by several mechanisms involving specialized ribosome regions and external factors, ensures the precise reading of sense as well as stop codons (UGA, UAG, UAA), which are usually localized at the 3' of mRNA and drive the release of the polypeptide chain. However, either natural (NTCs) or premature (PTCs) termination codons, the latter arising from nucleotide changes, can undergo a recoding process named ribosome or translational readthrough, which insert specific amino acids (NTCs) or subset(s) depending on the stop codon type (PTCs). This process is particularly relevant for nonsense mutations, a relatively frequent cause of genetic disorders, which impair gene expression at different levels by potentially leading to mRNA degradation and/or synthesis of truncated proteins. As a matter of fact, many efforts have been made to develop efficient and safe readthrough-inducing compounds, which have been challenged in several models of human disease to provide with a therapy. In this view, the dissection of the molecular determinants shaping the outcome of readthrough, namely nucleotide and protein contexts as well as their interplay and impact on protein structure/function, is crucial to identify responsive nonsense mutations resulting in functional full-length proteins. The interpretation of experimental and mechanistic findings is also important to define a possibly clear picture of potential readthrough-favorable features useful to achieve rescue profiles compatible with therapeutic thresholds typical of each targeted disorder, which is of primary importance for the potential translatability of readthrough into a personalized and mutation-specific, and thus patient-oriented, therapeutic strategy.
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Affiliation(s)
- Silvia Lombardi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Maria Francesca Testa
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Alessio Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
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7
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Paromomycin Reduces Vairimorpha (Nosema) ceranae Infection in Honey Bees but Perturbs Microbiome Levels and Midgut Cell Function. Microorganisms 2022; 10:microorganisms10061107. [PMID: 35744625 PMCID: PMC9231153 DOI: 10.3390/microorganisms10061107] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 02/04/2023] Open
Abstract
Paromomycin is a naturally occurring aminoglycoside antibiotic that has effects on both prokaryotic and eukaryotic microbes. However, previous reports have indicated that it has little effect on microsporidia, including Vairimorpha (Nosema) ceranae, in cell culture models. V. ceranae is one of a number of microsporidia species that cause disease in honey bees and substantial efforts to find new treatment strategies for bees that are infected with these pathogens are ongoing. When testing compounds for potential activity against V. ceranae in whole organisms, we found that paromomycin reduces the infection intensity of this parasite. Critically, the necessary doses of paromomycin have high activity against the bacteria of the honey bee microbiome and cause evident stress in bees. Microsporidia have been shown to lack an essential binding site on the ribosome that is known to allow for maximal inhibition by paromomycin. Thus, it is possible that paromomycin impacts parasite levels through non-cell autonomous effects on microsporidia infection levels via effects on the microbiome or midgut cellular function. As paromomycin treatment could cause widespread honey bee health issues in agricultural settings, it does not represent an appropriate anti-microsporidia agent for use in the field.
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8
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Houston L, Platten EM, Connelly SM, Wang J, Grayhack EJ. Frameshifting at collided ribosomes is modulated by elongation factor eEF3 and by integrated stress response regulators Gcn1 and Gcn20. RNA (NEW YORK, N.Y.) 2022; 28:320-339. [PMID: 34916334 PMCID: PMC8848926 DOI: 10.1261/rna.078964.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
Ribosome stalls can result in ribosome collisions that elicit quality control responses, one function of which is to prevent ribosome frameshifting, an activity that entails the interaction of the conserved yeast protein Mbf1 with uS3 on colliding ribosomes. However, the full spectrum of factors that mediate frameshifting during ribosome collisions is unknown. To delineate such factors in the yeast Saccharomyces cerevisiae, we used genetic selections for mutants that affect frameshifting from a known ribosome stall site, CGA codon repeats. We show that the general translation elongation factor eEF3 and the integrated stress response (ISR) pathway components Gcn1 and Gcn20 modulate frameshifting in opposing manners. We found a mutant form of eEF3 that specifically suppressed frameshifting, but not translation inhibition by CGA codons. Thus, we infer that frameshifting at collided ribosomes requires eEF3, which facilitates tRNA-mRNA translocation and E-site tRNA release in yeast and other single cell organisms. In contrast, we found that removal of either Gcn1 or Gcn20, which bind collided ribosomes with Mbf1, increased frameshifting. Thus, we conclude that frameshifting is suppressed by Gcn1 and Gcn20, although these effects are not mediated primarily through activation of the ISR. Furthermore, we examined the relationship between eEF3-mediated frameshifting and other quality control mechanisms, finding that Mbf1 requires either Hel2 or Gcn1 to suppress frameshifting with wild-type eEF3. Thus, these results provide evidence of a direct link between translation elongation and frameshifting at collided ribosomes, as well as evidence that frameshifting is constrained by quality control mechanisms that act on collided ribosomes.
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Affiliation(s)
- Lisa Houston
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Evan M Platten
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Sara M Connelly
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Jiyu Wang
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Elizabeth J Grayhack
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
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9
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Therapeutic pipeline for individuals with cystic fibrosis with mutations nonresponsive to current cystic fibrosis transmembrane conductance regulator modulators. Curr Opin Pulm Med 2021; 27:567-574. [PMID: 34494979 DOI: 10.1097/mcp.0000000000000827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE OF REVIEW Cystic fibrosis is a severe autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) encoding the CFTR protein, a chloride channel expressed in many epithelial cells. New drugs called CFTR modulators aim at restoring the CFTR protein function and they will benefit most of the patients with cystic fibrosis in the near future. However, more than 10% of CFTR mutations do not produce any CFTR protein for CFTR modulators to act upon, and the purpose of this review is to provide an overview of different approaches pursued to treat patients bearing mutations nonresponsive to CFTR modulators. RECENT FINDINGS These different approaches constitute readthrough agents for nonsense mutations, nucleic acid-based therapies, RNA-based or DNA-based, and cell-based therapies. Some approaches using mRNA or cDNA combined with a delivery vehicle are mutation-agnostic therapies. Other approaches, such as the use of tRNA, antisense oligonucleotides, gene editing or cell-based therapies are mutation-specific therapies. SUMMARY Most of these approaches are in preclinical development or for some of them, early clinical phases. Many hurdles and challenges will have to be solved before they can be safely translated to patients.
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Therapeutic Approaches for Patients with Cystic Fibrosis Not Eligible for Current CFTR Modulators. Cells 2021; 10:cells10102793. [PMID: 34685773 PMCID: PMC8534516 DOI: 10.3390/cells10102793] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/11/2021] [Accepted: 10/15/2021] [Indexed: 12/26/2022] Open
Abstract
Cystic fibrosis is a severe autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene encoding the CFTR protein, a chloride channel expressed in many epithelial cells. New drugs called CFTR modulators aim at restoring the CFTR protein function, and they will benefit many patients with cystic fibrosis in the near future. However, some patients bear rare mutations that are not yet eligible for CFTR modulators, although they might be amenable to these new disease-modifying drugs. Moreover, more than 10% of CFTR mutations do not produce any CFTR protein for CFTR modulators to act upon. The purpose of this review is to provide an overview of different approaches pursued to treat patients bearing mutations ineligible for CFTR modulators. One approach is to broaden the numbers of mutations eligible for CFTR modulators. This requires developing strategies to evaluate drugs in populations bearing very rare genotypes. Other approaches aiming at correcting the CFTR defect develop new mutation-specific or mutation-agnostic therapies for mutations that do not produce a CFTR protein: readthrough agents for nonsense mutations, nucleic acid-based therapies, RNA- or DNA-based, and cell-based therapies. Most of these approaches are in pre-clinical development or, for some of them, early clinical phases. Many hurdles and challenges will have to be solved before they can be safely translated to patients.
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11
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Dmitriev SE, Vladimirov DO, Lashkevich KA. A Quick Guide to Small-Molecule Inhibitors of Eukaryotic Protein Synthesis. BIOCHEMISTRY (MOSCOW) 2021; 85:1389-1421. [PMID: 33280581 PMCID: PMC7689648 DOI: 10.1134/s0006297920110097] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eukaryotic ribosome and cap-dependent translation are attractive targets in the antitumor, antiviral, anti-inflammatory, and antiparasitic therapies. Currently, a broad array of small-molecule drugs is known that specifically inhibit protein synthesis in eukaryotic cells. Many of them are well-studied ribosome-targeting antibiotics that block translocation, the peptidyl transferase center or the polypeptide exit tunnel, modulate the binding of translation machinery components to the ribosome, and induce miscoding, premature termination or stop codon readthrough. Such inhibitors are widely used as anticancer, anthelmintic and antifungal agents in medicine, as well as fungicides in agriculture. Chemicals that affect the accuracy of stop codon recognition are promising drugs for the nonsense suppression therapy of hereditary diseases and restoration of tumor suppressor function in cancer cells. Other compounds inhibit aminoacyl-tRNA synthetases, translation factors, and components of translation-associated signaling pathways, including mTOR kinase. Some of them have antidepressant, immunosuppressive and geroprotective properties. Translation inhibitors are also used in research for gene expression analysis by ribosome profiling, as well as in cell culture techniques. In this article, we review well-studied and less known inhibitors of eukaryotic protein synthesis (with the exception of mitochondrial and plastid translation) classified by their targets and briefly describe the action mechanisms of these compounds. We also present a continuously updated database (http://eupsic.belozersky.msu.ru/) that currently contains information on 370 inhibitors of eukaryotic protein synthesis.
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Affiliation(s)
- S E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia. .,Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - D O Vladimirov
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - K A Lashkevich
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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12
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Porter JJ, Heil CS, Lueck JD. Therapeutic promise of engineered nonsense suppressor tRNAs. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 12:e1641. [PMID: 33567469 PMCID: PMC8244042 DOI: 10.1002/wrna.1641] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022]
Abstract
Nonsense mutations change an amino acid codon to a premature termination codon (PTC) generally through a single-nucleotide substitution. The generation of a PTC results in a defective truncated protein and often in severe forms of disease. Because of the exceedingly high prevalence of nonsense-associated diseases and a unifying mechanism, there has been a concerted effort to identify PTC therapeutics. Most clinical trials for PTC therapeutics have been conducted with small molecules that promote PTC read through and incorporation of a near-cognate amino acid. However, there is a need for PTC suppression agents that recode PTCs with the correct amino acid while being applicable to PTC mutations in many different genomic landscapes. With these characteristics, a single therapeutic will be able to treat several disease-causing PTCs. In this review, we will focus on the use of nonsense suppression technologies, in particular, suppressor tRNAs (sup-tRNAs), as possible therapeutics for correcting PTCs. Sup-tRNAs have many attractive qualities as possible therapeutic agents although there are knowledge gaps on their function in mammalian cells and technical hurdles that need to be overcome before their promise is realized. This article is categorized under: RNA Processing > tRNA Processing Translation > Translation Regulation.
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Affiliation(s)
- Joseph J. Porter
- Department of Pharmacology and PhysiologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - Christina S. Heil
- Department of Pharmacology and PhysiologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
| | - John D. Lueck
- Department of Pharmacology and PhysiologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
- Department of NeurologyUniversity of Rochester Medical CenterRochesterNew YorkUSA
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13
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Martins-Dias P, Romão L. Nonsense suppression therapies in human genetic diseases. Cell Mol Life Sci 2021; 78:4677-4701. [PMID: 33751142 PMCID: PMC11073055 DOI: 10.1007/s00018-021-03809-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/06/2021] [Accepted: 03/05/2021] [Indexed: 02/06/2023]
Abstract
About 11% of all human disease-associated gene lesions are nonsense mutations, resulting in the introduction of an in-frame premature translation-termination codon (PTC) into the protein-coding gene sequence. When translated, PTC-containing mRNAs originate truncated and often dysfunctional proteins that might be non-functional or have gain-of-function or dominant-negative effects. Therapeutic strategies aimed at suppressing PTCs to restore deficient protein function-the so-called nonsense suppression (or PTC readthrough) therapies-have the potential to provide a therapeutic benefit for many patients and in a broad range of genetic disorders, including cancer. These therapeutic approaches comprise the use of translational readthrough-inducing compounds that make the translational machinery recode an in-frame PTC into a sense codon. However, most of the mRNAs carrying a PTC can be rapidly degraded by the surveillance mechanism of nonsense-mediated decay (NMD), thus decreasing the levels of PTC-containing mRNAs in the cell and their availability for PTC readthrough. Accordingly, the use of NMD inhibitors, or readthrough-compound potentiators, may enhance the efficiency of PTC suppression. Here, we review the mechanisms of PTC readthrough and their regulation, as well as the recent advances in the development of novel approaches for PTC suppression, and their role in personalized medicine.
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Affiliation(s)
- Patrícia Martins-Dias
- Department of Human Genetics, Instituto Nacional de Saúde Doutor Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
- Faculty of Sciences, BioISI-Biosystems and Integrative Sciences Institute, University of Lisboa, 1749-016, Lisbon, Portugal
| | - Luísa Romão
- Department of Human Genetics, Instituto Nacional de Saúde Doutor Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.
- Faculty of Sciences, BioISI-Biosystems and Integrative Sciences Institute, University of Lisboa, 1749-016, Lisbon, Portugal.
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Rathner A, Rathner P, Friedrich A, Wießner M, Kitzler CM, Schernthaner J, Karl T, Krauß J, Lottspeich F, Mewes W, Hintner H, Bauer JW, Breitenbach M, Müller N, Breitenbach-Koller H, von Hagen J. Drug Development for Target Ribosomal Protein rpL35/uL29 for Repair of LAMB3R635X in Rare Skin Disease Epidermolysis Bullosa. Skin Pharmacol Physiol 2021; 34:167-182. [PMID: 33823521 DOI: 10.1159/000513260] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/22/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Epidermolysis bullosa (EB) describes a family of rare genetic blistering skin disorders. Various subtypes are clinically and genetically heterogeneous, and a lethal postpartum form of EB is the generalized severe junctional EB (gs-JEB). gs-JEB is mainly caused by premature termination codon (PTC) mutations in the skin anchor protein LAMB3 (laminin subunit beta-3) gene. The ribosome in majority of translational reads of LAMB3PTC mRNA aborts protein synthesis at the PTC signal, with production of a truncated, nonfunctional protein. This leaves an endogenous readthrough mechanism needed for production of functional full-length Lamb3 protein albeit at insufficient levels. Here, we report on the development of drugs targeting ribosomal protein L35 (rpL35), a ribosomal modifier for customized increase in production of full-length Lamb3 protein from a LAMB3PTC mRNA. METHODS Molecular docking studies were employed to identify small molecules binding to human rpL35. Molecular determinants of small molecule binding to rpL35 were further characterized by titration of the protein with these ligands as monitored by nuclear magnetic resonance (NMR) spectroscopy in solution. Changes in NMR chemical shifts were used to map the docking sites for small molecules onto the 3D structure of the rpL35. RESULTS Molecular docking studies identified 2 FDA-approved drugs, atazanavir and artesunate, as candidate small-molecule binders of rpL35. Molecular interaction studies predicted several binding clusters for both compounds scattered throughout the rpL35 structure. NMR titration studies identified the amino acids participating in the ligand interaction. Combining docking predictions for atazanavir and artesunate with rpL35 and NMR analysis of rpL35 ligand interaction, one binding cluster located near the N-terminus of rpL35 was identified. In this region, the nonidentical binding sites for atazanavir and artesunate overlap and are accessible when rpL35 is integrated in its natural ribosomal environment. CONCLUSION Atazanavir and artesunate were identified as candidate compounds binding to ribosomal protein rpL35 and may now be tested for their potential to trigger a rpL35 ribosomal switch to increase production of full-length Lamb3 protein from a LAMB3PTC mRNA for targeted systemic therapy in treating gs-JEB.
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Affiliation(s)
- Adriana Rathner
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Petr Rathner
- Department of Biosciences, University of Salzburg, Salzburg, Austria
- Institute of Inorganic Chemistry, Johannes Kepler University, Linz, Austria
| | - Andreas Friedrich
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Michael Wießner
- Department of Biosciences, University of Salzburg, Salzburg, Austria
- Department of Allergology and Dermatology, University Hospital Salzburg, Salzburg, Austria
| | | | - Jan Schernthaner
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Thomas Karl
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Jan Krauß
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | | | - Werner Mewes
- TUM School of Life Sciences, Technical University of Munich, Munich, Germany
| | - Helmut Hintner
- Department of Biosciences, University of Salzburg, Salzburg, Austria
- Department of Allergology and Dermatology, University Hospital Salzburg, Salzburg, Austria
| | - Johann W Bauer
- Department of Biosciences, University of Salzburg, Salzburg, Austria
- Department of Allergology and Dermatology, University Hospital Salzburg, Salzburg, Austria
| | | | - Norbert Müller
- Institute of Inorganic Chemistry, Johannes Kepler University, Linz, Austria
- Institute of Organic Chemistry, Johannes Kepler University, Linz, Austria
- Faculty of Natural Sciences, University of South Bohemia, Ceske Budejovice, Czechia
| | | | - Jörg von Hagen
- Department of Life Science Engineering, Technische Hochschule Mittelhessen, Gießen, Germany
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15
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Dalhoff A. Selective toxicity of antibacterial agents-still a valid concept or do we miss chances and ignore risks? Infection 2021; 49:29-56. [PMID: 33367978 PMCID: PMC7851017 DOI: 10.1007/s15010-020-01536-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/04/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Selective toxicity antibacteribiotics is considered to be due to interactions with targets either being unique to bacteria or being characterized by a dichotomy between pro- and eukaryotic pathways with high affinities of agents to bacterial- rather than eukaryotic targets. However, the theory of selective toxicity oversimplifies the complex modes of action of antibiotics in pro- and eukaryotes. METHODS AND OBJECTIVE This review summarizes data describing multiple modes of action of antibiotics in eukaryotes. RESULTS Aminoglycosides, macrolides, oxazolidinones, chloramphenicol, clindamycin, tetracyclines, glycylcyclines, fluoroquinolones, rifampicin, bedaquillin, ß-lactams inhibited mitochondrial translation either due to binding to mitosomes, inhibition of mitochondrial RNA-polymerase-, topoisomerase 2ß-, ATP-synthesis, transporter activities. Oxazolidinones, tetracyclines, vancomycin, ß-lactams, bacitracin, isoniazid, nitroxoline inhibited matrix-metalloproteinases (MMP) due to chelation with zinc and calcium, whereas fluoroquinols fluoroquinolones and chloramphenicol chelated with these cations, too, but increased MMP activities. MMP-inhibition supported clinical efficacies of ß-lactams and daptomycin in skin-infections, and of macrolides, tetracyclines in respiratory-diseases. Chelation may have contributed to neuroprotection by ß-lactams and fluoroquinolones. Aminoglycosides, macrolides, chloramphenicol, oxazolidins oxazolidinones, tetracyclines caused read-through of premature stop codons. Several additional targets for antibiotics in human cells have been identified like interaction of fluoroquinolones with DNA damage repair in eukaryotes, or inhibition of mucin overproduction by oxazolidinones. CONCLUSION The effects of antibiotics on eukaryotes are due to identical mechanisms as their antibacterial activities because of structural and functional homologies of pro- and eukaryotic targets, so that the effects of antibiotics on mammals are integral parts of their overall mechanisms of action.
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Affiliation(s)
- Axel Dalhoff
- Christian-Albrechts-University of Kiel, Institue for Infection Medicine, Brunswiker Str. 4, D-24105, Kiel, Germany.
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16
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Molecular Insights into Determinants of Translational Readthrough and Implications for Nonsense Suppression Approaches. Int J Mol Sci 2020; 21:ijms21249449. [PMID: 33322589 PMCID: PMC7764779 DOI: 10.3390/ijms21249449] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 11/27/2020] [Accepted: 12/05/2020] [Indexed: 02/07/2023] Open
Abstract
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.
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17
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Ghosh A, Shcherbik N. Cooperativity between the Ribosome-Associated Chaperone Ssb/RAC and the Ubiquitin Ligase Ltn1 in Ubiquitination of Nascent Polypeptides. Int J Mol Sci 2020; 21:ijms21186815. [PMID: 32957466 PMCID: PMC7554835 DOI: 10.3390/ijms21186815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/12/2020] [Accepted: 09/14/2020] [Indexed: 11/25/2022] Open
Abstract
Eukaryotic cells have evolved multiple mechanisms to detect and eliminate aberrant polypeptides. Co-translational protein surveillance systems play an important role in these mechanisms. These systems include ribosome-associated protein quality control (RQC) that detects aberrant nascent chains stalled on ribosomes and promotes their ubiquitination and degradation by the proteasome, and ribosome-associated chaperone Ssb/RAC, which ensures correct nascent chain folding. Despite the known function of RQC and Ssb/ribosome-associated complex (RAC) in monitoring the quality of newly generated polypeptides, whether they cooperate during initial stages of protein synthesis remains unexplored. Here, we provide evidence that Ssb/RAC and the ubiquitin ligase Ltn1, the major component of RQC, display genetic and functional cooperativity. Overexpression of Ltn1 rescues growth suppression of the yeast strain-bearing deletions of SSB genes during proteotoxic stress. Moreover, Ssb/RAC promotes Ltn1-dependent ubiquitination of nascent chains associated with 80S ribosomal particles but not with translating ribosomes. Consistent with this finding, quantitative western blot analysis revealed lower levels of Ltn1 associated with 80S ribosomes and with free 60S ribosomal subunits in the absence of Ssb/RAC. We propose a mechanism in which Ssb/RAC facilitates recruitment of Ltn1 to ribosomes, likely by detecting aberrations in nascent chains and leading to their ubiquitination and degradation.
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18
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Gribling-Burrer AS, Chiabudini M, Zhang Y, Qiu Z, Scazzari M, Wölfle T, Wohlwend D, Rospert S. A dual role of the ribosome-bound chaperones RAC/Ssb in maintaining the fidelity of translation termination. Nucleic Acids Res 2020; 47:7018-7034. [PMID: 31114879 PMCID: PMC6648330 DOI: 10.1093/nar/gkz334] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/05/2019] [Accepted: 04/25/2019] [Indexed: 11/22/2022] Open
Abstract
The yeast ribosome-associated complex RAC and the Hsp70 homolog Ssb are anchored to the ribosome and together act as chaperones for the folding and co-translational assembly of nascent polypeptides. In addition, the RAC/Ssb system plays a crucial role in maintaining the fidelity of translation termination; however, the latter function is poorly understood. Here we show that the RAC/Ssb system promotes the fidelity of translation termination via two distinct mechanisms. First, via direct contacts with the ribosome and the nascent chain, RAC/Ssb facilitates the translation of stalling-prone poly-AAG/A sequences encoding for polylysine segments. Impairment of this function leads to enhanced ribosome stalling and to premature nascent polypeptide release at AAG/A codons. Second, RAC/Ssb is required for the assembly of fully functional ribosomes. When RAC/Ssb is absent, ribosome biogenesis is hampered such that core ribosomal particles are structurally altered at the decoding and peptidyl transferase centers. As a result, ribosomes assembled in the absence of RAC/Ssb bind to the aminoglycoside paromomycin with high affinity (KD = 76.6 nM) and display impaired discrimination between stop codons and sense codons. The combined data shed light on the multiple mechanisms by which the RAC/Ssb system promotes unimpeded biogenesis of newly synthesized polypeptides.
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Affiliation(s)
- Anne-Sophie Gribling-Burrer
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, University of Freiburg, D-79104 Freiburg, Germany
| | - Marco Chiabudini
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, University of Freiburg, D-79104 Freiburg, Germany
| | - Ying Zhang
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, University of Freiburg, D-79104 Freiburg, Germany
| | - Zonghao Qiu
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, University of Freiburg, D-79104 Freiburg, Germany
| | - Mario Scazzari
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, University of Freiburg, D-79104 Freiburg, Germany
| | - Tina Wölfle
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, University of Freiburg, D-79104 Freiburg, Germany
| | - Daniel Wohlwend
- Institute of Biochemistry, Chemical and Pharmaceutical Faculty, University of Freiburg, D-79104 Freiburg, Germany
| | - Sabine Rospert
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, University of Freiburg, D-79104 Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, D-79104 Freiburg, Germany
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19
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Serum starvation enhances nonsense mutation readthrough. J Mol Med (Berl) 2019; 97:1695-1710. [PMID: 31786671 DOI: 10.1007/s00109-019-01847-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/03/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022]
Abstract
Of all genetic mutations causing human disease, premature termination codons (PTCs) that result from splicing defaults, insertions, deletions, and point mutations comprise around 30%. From these mutations, around 11% are a substitution of a single nucleotide that change a codon into a premature termination codon. These types of mutations affect several million patients suffering from a large variety of genetic diseases, ranging from relatively common inheritable cancer syndromes to muscular dystrophy or very rare neuro-metabolic disorders. Over the past three decades, genetic and biochemical studies have revealed that certain antibiotics and other synthetic molecules can act as nonsense mutation readthrough-inducing drugs. These compounds bind a specific site on the rRNA and, as a result, the stop codon is misread and an amino acid (that may or may not differ from the wild-type amino acid) is inserted and translation occurs through the premature termination codon. This strategy has great therapeutic potential. Unfortunately, many readthrough agents are toxic and cannot be administered over the extended period usually required for the chronic treatment of genetic diseases. Furthermore, readthrough compounds only restore protein production in very few disease models and the readthrough levels are usually low, typically achieving no more than 5% of normal protein expression. Efforts have been made over the years to overcome these obstacles so that readthrough treatment can become clinically relevant. Here, we present the creation of a stable cell line system that constitutively expresses our dual-reporter vector harboring two cancer initiating nonsense mutations in the adenomatous polyposis coli (APC) gene. This system will be used as an improved screening method for isolation of new nonsense mutation readthrough inducers. Using these cell lines as well as colorectal cancer cell lines, we demonstrate that serum starvation enhances drug-induced readthrough activity, an observation which may prove beneficial in a therapeutic scenario that requires higher levels of the restored protein. KEY MESSAGES: Nonsense mutations affects millions of people worldwide. We have developed a nonsense mutation read-through screening tool. We find that serum starvation enhances antibiotic-induced nonsense mutation read-through. Our results suggest new strategies for enhancing nonsense mutation read-through that may have positive effects on a large number of patients.
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20
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Shahi PK, Hermans D, Sinha D, Brar S, Moulton H, Stulo S, Borys KD, Capowski E, Pillers DAM, Gamm DM, Pattnaik BR. Gene Augmentation and Readthrough Rescue Channelopathy in an iPSC-RPE Model of Congenital Blindness. Am J Hum Genet 2019; 104:310-318. [PMID: 30686507 DOI: 10.1016/j.ajhg.2018.12.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022] Open
Abstract
Pathogenic variants of the KCNJ13 gene are known to cause Leber congenital amaurosis (LCA16), an inherited pediatric blindness. KCNJ13 encodes the Kir7.1 subunit that acts as a tetrameric, inwardly rectifying potassium ion channel in the retinal pigment epithelium (RPE) to maintain ionic homeostasis and allow photoreceptors to encode visual information. We sought to determine whether genetic approaches might be effective in treating blindness arising from pathogenic variants in KCNJ13. We derived human induced pluripotent stem cell (hiPSC)-RPE cells from an individual carrying a homozygous c.158G>A (p.Trp53∗) pathogenic variant of KCNJ13. We performed biochemical and electrophysiology assays to confirm Kir7.1 function. We tested both small-molecule readthrough drug and gene-therapy approaches for this "disease-in-a-dish" approach. We found that the LCA16 hiPSC-RPE cells had normal morphology but did not express a functional Kir7.1 channel and were unable to demonstrate normal physiology. After readthrough drug treatment, the LCA16 hiPSC cells were hyperpolarized by 30 mV, and the Kir7.1 current was restored. Similarly, we rescued Kir7.1 channel function after lentiviral gene delivery to the hiPSC-RPE cells. In both approaches, Kir7.1 was expressed normally, and there was restoration of membrane potential and the Kir7.1 current. Loss-of-function variants of Kir7.1 are one cause of LCA. Using either readthrough therapy or gene augmentation, we rescued Kir7.1 channel function in iPSC-RPE cells derived from an affected individual. This supports the development of precision-medicine approaches for the treatment of clinical LCA16.
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Affiliation(s)
- Pawan K Shahi
- Division of Neonatology, Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA; McPherson Eye Research, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Dalton Hermans
- Division of Neonatology, Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Divya Sinha
- McPherson Eye Research, University of Wisconsin-Madison, Madison, WI 53705, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Simran Brar
- Division of Neonatology, Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hannah Moulton
- Division of Neonatology, Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sabrina Stulo
- Division of Neonatology, Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Katarzyna D Borys
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Elizabeth Capowski
- McPherson Eye Research, University of Wisconsin-Madison, Madison, WI 53705, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - De-Ann M Pillers
- Division of Neonatology, Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA; McPherson Eye Research, University of Wisconsin-Madison, Madison, WI 53705, USA; Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - David M Gamm
- McPherson Eye Research, University of Wisconsin-Madison, Madison, WI 53705, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Bikash R Pattnaik
- Division of Neonatology, Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA; McPherson Eye Research, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA.
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21
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Zhou J, Qiu C, Pi N, Li S, Cheng X, Zhang L, Chen Y, Huang Y, Sun Y, Su Z. A Protein Biosynthesis Machinery Strategy for Identifying P53 PTC
-Rescuing Compounds as Synergic Anti-Tumor Drugs. ChemistrySelect 2018. [DOI: 10.1002/slct.201802635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jingjing Zhou
- Department of Biotechnology; Hubei University of Technology, Wuhan, Hubei; 430068 P. R. China
| | - Chengbin Qiu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University); Ministry of Education and Wuhan University; School of Pharmaceutical Sciences Wuhan; Hubei 430071 P. R. China
| | - Ni Pi
- Department of Biotechnology; Hubei University of Technology, Wuhan, Hubei; 430068 P. R. China
| | - Sicong Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University); Ministry of Education and Wuhan University; School of Pharmaceutical Sciences Wuhan; Hubei 430071 P. R. China
| | - Xiyao Cheng
- Department of Biotechnology; Hubei University of Technology, Wuhan, Hubei; 430068 P. R. China
| | - Lei Zhang
- Department of Biotechnology; Hubei University of Technology, Wuhan, Hubei; 430068 P. R. China
| | - Yao Chen
- Department of Biotechnology; Hubei University of Technology, Wuhan, Hubei; 430068 P. R. China
| | - Yongqi Huang
- Department of Biotechnology; Hubei University of Technology, Wuhan, Hubei; 430068 P. R. China
| | - Yuhui Sun
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University); Ministry of Education and Wuhan University; School of Pharmaceutical Sciences Wuhan; Hubei 430071 P. R. China
| | - Zhengding Su
- Department of Biotechnology; Hubei University of Technology, Wuhan, Hubei; 430068 P. R. China
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22
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Vallières C, Raulo R, Dickinson M, Avery SV. Novel Combinations of Agents Targeting Translation That Synergistically Inhibit Fungal Pathogens. Front Microbiol 2018; 9:2355. [PMID: 30349511 PMCID: PMC6186996 DOI: 10.3389/fmicb.2018.02355] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/14/2018] [Indexed: 12/29/2022] Open
Abstract
A range of fungicides or antifungals are currently deployed to control fungi in agriculture or medicine, but resistance to current agents is growing so new approaches and molecular targets are urgently needed. Recently, different aminoglycoside antibiotics combined with particular transport inhibitors were found to produce strong, synergistic growth-inhibition of fungi, by synergistically increasing the error rate of mRNA translation. Here, focusing on translation fidelity as a novel target for combinatorial antifungal treatment, we tested the hypothesis that alternative combinations of agents known to affect the availability of functional amino acids would synergistically inhibit growth of major fungal pathogens. We screened 172 novel combinations against three phytopathogens (Rhizoctonia solani, Zymoseptoria tritici, and Botrytis cinerea) and three human pathogens (Cryptococcus neoformans, Candida albicans, and Aspergillus fumigatus), showing that 48 combinations inhibited strongly the growth of the pathogens; the growth inhibition effect was significantly greater with the agents combined than by a simple product of their individual effects at the same doses. Of these, 23 combinations were effective against more than one pathogen, including combinations comprising food-and-drug approved compounds, e.g., quinine with bicarbonate, and quinine with hygromycin. These combinations [fractional inhibitory combination (FIC) index ≤0.5] gave up to 100% reduction of fungal growth yield at concentrations of agents which, individually, had negligible effect. No synergy was evident against bacterial, plant or mammalian cells, indicating specificity for fungi. Mode-of-action analyses for quinine + hygromycin indicated that synergistic mistranslation was the antifungal mechanism. That mechanism was not universal as bicarbonate exacerbated quinine action by increasing drug uptake. The study unveils chemical combinations and a target process with potential for control of diverse fungal pathogens, and suggests repurposing possibilities for several current therapeutics.
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Affiliation(s)
- Cindy Vallières
- School of Life Sciences, University of Nottingham, University Park Campus, Nottingham, United Kingdom
| | - Roxane Raulo
- School of Life Sciences, University of Nottingham, University Park Campus, Nottingham, United Kingdom
| | - Matthew Dickinson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Simon V Avery
- School of Life Sciences, University of Nottingham, University Park Campus, Nottingham, United Kingdom
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23
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Dabrowski M, Bukowy-Bieryllo Z, Zietkiewicz E. Advances in therapeutic use of a drug-stimulated translational readthrough of premature termination codons. Mol Med 2018; 24:25. [PMID: 30134808 PMCID: PMC6016875 DOI: 10.1186/s10020-018-0024-7] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/01/2018] [Indexed: 12/31/2022] Open
Abstract
Premature termination codons (PTCs) in the coding regions of mRNA lead to the incorrect termination of translation and generation of non-functional, truncated proteins. Translational readthrough of PTCs induced by pharmaceutical compounds is a promising way of restoring functional protein expression and reducing disease symptoms, without affecting the genome or transcriptome of the patient. While in some cases proven effective, the clinical use of readthrough-inducing compounds is still associated with many risks and difficulties. This review focuses on problems directly associated with compounds used to stimulate PTC readthrough, such as their interactions with the cell and organism, their toxicity and bioavailability (cell permeability; tissue deposition etc.). Various strategies designed to overcome these problems are presented.
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Affiliation(s)
- Maciej Dabrowski
- Institute of Human Genetics; Polish Academy of Sciences, Poznan, Poland
| | | | - Ewa Zietkiewicz
- Institute of Human Genetics; Polish Academy of Sciences, Poznan, Poland.
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24
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Wojciechowska M, Dudek M, Trylska J. Thermodynamics of the pseudo-knot in helix 18 of 16S ribosomal RNA. Biopolymers 2018; 109:e23116. [PMID: 29570767 DOI: 10.1002/bip.23116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/24/2018] [Accepted: 02/27/2018] [Indexed: 01/13/2023]
Abstract
A fragment of E. coli 16S rRNA formed by nucleotides 500 to 545 is termed helix 18. Nucleotides 505-507 and 524-526 form a pseudo-knot and its distortion affects ribosome function. Helix 18 isolated from the ribosome context is thus an interesting fragment to investigate the structural properties and folding of RNA with pseudo-knots. With all-atom molecular dynamics simulations, spectroscopic and gel electrophoresis experiments, we investigated thermodynamics of helix 18, with a focus on its pseudo-knot. In solution studies at ambient conditions we observed dimerization of helix 18. We proposed that the loop, containing nucleotides forming the pseudo-knot, interacts with another monomer of helix 18. The native dimer is difficult to break but introducing mutations in the pseudo-knot indeed assured a monomeric form of helix 18. Molecular dynamics simulations at 310 K confirmed the stability of the pseudo-knot but at elevated temperatures this pseudo-knot was the first part of helix 18 to lose the hydrogen bond pattern. To further determine helix 18 stability, we analyzed the interactions of helix 18 with short oligomers complementary to a nucleotide stretch containing the pseudo-knot. The formation of higher-order structures by helix 18 impacts hybridization efficiency of peptide nucleic acid and 2'-O methyl RNA oligomers.
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Affiliation(s)
- Monika Wojciechowska
- Centre of New Technologies, University of Warsaw, Banacha 2C, Warsaw, 02-09, Poland
| | - Marta Dudek
- Centre of New Technologies, University of Warsaw, Banacha 2C, Warsaw, 02-09, Poland.,School of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland.,First Faculty of Medicine, Department of Hematology, Oncology and Internal Diseases, Medical University of Warsaw, Al. Żwirki i Wigury 61, Warsaw, 02-091, Poland
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Banacha 2C, Warsaw, 02-09, Poland
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25
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Zhang M, Heldin A, Palomar-Siles M, Öhlin S, Bykov VJN, Wiman KG. Synergistic Rescue of Nonsense Mutant Tumor Suppressor p53 by Combination Treatment with Aminoglycosides and Mdm2 Inhibitors. Front Oncol 2018; 7:323. [PMID: 29354595 PMCID: PMC5758538 DOI: 10.3389/fonc.2017.00323] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/12/2017] [Indexed: 12/13/2022] Open
Abstract
The tumor suppressor gene TP53 is inactivated by mutation in a large fraction of human tumors. Around 10% of TP53 mutations are nonsense mutations that lead to premature termination of translation and expression of truncated unstable and non-functional p53 protein. Aminoglycosides G418 (geneticin) and gentamicin have been shown to induce translational readthrough and expression of full-length p53. However, aminoglycosides have severe side effects that limit their clinical use. Here, we show that combination treatment with a proteasome inhibitor or compounds that disrupt p53-Mdm2 binding can synergistically enhance levels of full-length p53 upon aminoglycoside-induced readthrough of R213X nonsense mutant p53. Full-length p53 expressed upon combination treatment is functionally active as assessed by upregulation of p53 target genes, suppression of cell growth, and induction of cell death. Thus, our results demonstrate that combination treatment with aminoglycosides and compounds that inhibit p53 degradation is synergistic and can provide significantly improved efficacy of readthrough when compared with aminoglycosides alone. This may have implications for future cancer therapy based on reactivation of nonsense mutant TP53.
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Affiliation(s)
- Meiqiongzi Zhang
- Department of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Angelos Heldin
- Department of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Mireia Palomar-Siles
- Department of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Susanne Öhlin
- Department of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Vladimir J N Bykov
- Department of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Klas G Wiman
- Department of Oncology-Pathology, Cancer Center Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
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Abstract
Aminoglycosides are well known as antibiotics that target the bacterial ribosome. However, they also impact the eukaryotic translation mechanism to promote read-through of premature termination codons (PTCs) in mRNA. Aminoglycosides are therefore considered as potential therapies for PTC-associated human diseases. Here, we performed a comprehensive study of the mechanism of action of aminoglycosides in eukaryotes by applying a combination of structural and functional approaches. Our findings reveal complex interactions of aminoglycosides with eukaryotic 80S ribosome caused by their multiple binding sites, which lead to inhibition of intersubunit movement within the human ribosome that impact nearly every aspect of protein synthesis. Aminoglycosides are chemically diverse, broad-spectrum antibiotics that target functional centers within the bacterial ribosome to impact all four principle stages (initiation, elongation, termination, and recycling) of the translation mechanism. The propensity of aminoglycosides to induce miscoding errors that suppress the termination of protein synthesis supports their potential as therapeutic interventions in human diseases associated with premature termination codons (PTCs). However, the sites of interaction of aminoglycosides with the eukaryotic ribosome and their modes of action in eukaryotic translation remain largely unexplored. Here, we use the combination of X-ray crystallography and single-molecule FRET analysis to reveal the interactions of distinct classes of aminoglycosides with the 80S eukaryotic ribosome. Crystal structures of the 80S ribosome in complex with paromomycin, geneticin (G418), gentamicin, and TC007, solved at 3.3- to 3.7-Å resolution, reveal multiple aminoglycoside-binding sites within the large and small subunits, wherein the 6′-hydroxyl substituent in ring I serves as a key determinant of binding to the canonical eukaryotic ribosomal decoding center. Multivalent binding interactions with the human ribosome are also evidenced through their capacity to affect large-scale conformational dynamics within the pretranslocation complex that contribute to multiple aspects of the translation mechanism. The distinct impacts of the aminoglycosides examined suggest that their chemical composition and distinct modes of interaction with the ribosome influence PTC read-through efficiency. These findings provide structural and functional insights into aminoglycoside-induced impacts on the eukaryotic ribosome and implicate pleiotropic mechanisms of action beyond decoding.
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Yusupova G, Yusupov M. Crystal structure of eukaryotic ribosome and its complexes with inhibitors. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0184. [PMID: 28138070 DOI: 10.1098/rstb.2016.0184] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2016] [Indexed: 01/26/2023] Open
Abstract
A high-resolution structure of the eukaryotic ribosome has been determined and has led to increased interest in studying protein biosynthesis and regulation of biosynthesis in cells. The functional complexes of the ribosome crystals obtained from bacteria and yeast have permitted researchers to identify the precise residue positions in different states of ribosome function. This knowledge, together with electron microscopy studies, enhances our understanding of how basic ribosome processes, including mRNA decoding, peptide bond formation, mRNA, and tRNA translocation and cotranslational transport of the nascent peptide, are regulated. In this review, we discuss the crystal structure of the entire 80S ribosome from yeast, which reveals its eukaryotic-specific features, and application of X-ray crystallography of the 80S ribosome for investigation of the binding mode for distinct compounds known to inhibit or modulate the protein-translation function of the ribosome. We also refer to a challenging aspect of the structural study of ribosomes, from higher eukaryotes, where the structures of major distinctive features of higher eukaryote ribosome-the high-eukaryote-specific long ribosomal RNA segments (about 1MDa)-remain unresolved. Presently, the structures of the major part of these high-eukaryotic expansion ribosomal RNA segments still remain unresolved.This article is part of the themed issue 'Perspectives on the ribosome'.
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Affiliation(s)
- Gulnara Yusupova
- Department of Integrated Structural Biology, Institute of Genetics and of Molecular and Cellular Biology, CNRS/INSERM, University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France
| | - Marat Yusupov
- Department of Integrated Structural Biology, Institute of Genetics and of Molecular and Cellular Biology, CNRS/INSERM, University of Strasbourg, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France
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28
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The Candidate Antimalarial Drug MMV665909 Causes Oxygen-Dependent mRNA Mistranslation and Synergizes with Quinoline-Derived Antimalarials. Antimicrob Agents Chemother 2017; 61:AAC.00459-17. [PMID: 28652237 PMCID: PMC5571370 DOI: 10.1128/aac.00459-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/17/2017] [Indexed: 12/18/2022] Open
Abstract
To cope with growing resistance to current antimalarials, new drugs with novel modes of action are urgently needed. Molecules targeting protein synthesis appear to be promising candidates. We identified a compound (MMV665909) from the Medicines for Malaria Venture (MMV) Malaria Box of candidate antimalarials that could produce synergistic growth inhibition with the aminoglycoside antibiotic paromomycin, suggesting a possible action of the compound in mRNA mistranslation. This mechanism of action was substantiated with a Saccharomyces cerevisiae model using available reporters of mistranslation and other genetic tools. Mistranslation induced by MMV665909 was oxygen dependent, suggesting a role for reactive oxygen species (ROS). Overexpression of Rli1 (a ROS-sensitive, conserved FeS protein essential in mRNA translation) rescued inhibition by MMV665909, consistent with the drug's action on translation fidelity being mediated through Rli1. The MMV drug also synergized with major quinoline-derived antimalarials which can perturb amino acid availability or promote ROS stress: chloroquine, amodiaquine, and primaquine. The data collectively suggest translation fidelity as a novel target of antimalarial action and support MMV665909 as a promising drug candidate.
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Abstract
A wide range of fungicides (or antifungals) are used in agriculture and medicine, with activities against a spectrum of fungal pathogens. Unfortunately, the evolution of fungicide resistance has become a major issue. Therefore, there is an urgent need for new antifungal treatments. Certain metals have been used for decades as efficient fungicides in agriculture. However, concerns over metal toxicity have escalated over this time. Recent studies have revealed that metals like copper and chromate can impair functions required for the fidelity of protein synthesis in fungi. This occurs through different mechanisms, based on targeting of iron-sulphur cluster integrity or competition for uptake with amino acid precursors. Moreover, chromate at least acts synergistically with other agents known to target translation fidelity, like aminoglycoside antibiotics, causing dramatic and selective growth inhibition of several fungal pathogens of humans and plants. As such synergy allows the application of decreased amounts of metals for effective inhibition, it lessens concerns about nonspecific toxicity and opens new possibilities for metal applications in combinatorial fungicides targeting protein synthesis.
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Affiliation(s)
- Cindy Vallières
- School of Life Sciences, University of Nottingham University Park, Nottingham, United Kingdom
| | - Simon V Avery
- School of Life Sciences, University of Nottingham University Park, Nottingham, United Kingdom.
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30
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Richardson R, Smart M, Tracey-White D, Webster AR, Moosajee M. Mechanism and evidence of nonsense suppression therapy for genetic eye disorders. Exp Eye Res 2017; 155:24-37. [PMID: 28065590 DOI: 10.1016/j.exer.2017.01.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/24/2016] [Accepted: 01/04/2017] [Indexed: 01/09/2023]
Abstract
Between 5 and 70% of genetic disease is caused by in-frame nonsense mutations, which introduce a premature termination codon (PTC) within the disease-causing gene. Consequently, during translation, non-functional or gain-of-function truncated proteins of pathological significance, are formed. Approximately 50% of all inherited retinal disorders have been associated with PTCs, highlighting the importance of novel pharmacological or gene correction therapies in ocular disease. Pharmacological nonsense suppression of PTCs could delineate a therapeutic strategy that treats the mutation in a gene- and disease-independent manner. This approach aims to suppress the fidelity of the ribosome during protein synthesis so that a near-cognate aminoacyl-tRNA, which shares two of the three nucleotides of the PTC, can be inserted into the peptide chain, allowing translation to continue, and a full-length functional protein to be produced. Here we discuss the mechanisms and evidence of nonsense suppression agents, including the small molecule drug ataluren (or PTC124) and next generation 'designer' aminoglycosides, for the treatment of genetic eye disease.
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Affiliation(s)
- Rose Richardson
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK
| | - Matthew Smart
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK
| | - Dhani Tracey-White
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK
| | - Andrew R Webster
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Mariya Moosajee
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK.
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31
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Zhang X, Lai M, Chang W, Yu I, Ding K, Mrazek J, Ng HL, Yang OO, Maslov DA, Zhou ZH. Structures and stabilization of kinetoplastid-specific split rRNAs revealed by comparing leishmanial and human ribosomes. Nat Commun 2016; 7:13223. [PMID: 27752045 PMCID: PMC5071889 DOI: 10.1038/ncomms13223] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/13/2016] [Indexed: 11/17/2022] Open
Abstract
The recent success in ribosome structure determination by cryoEM has opened the door to defining structural differences between ribosomes of pathogenic organisms and humans and to understand ribosome-targeting antibiotics. Here, by direct electron-counting cryoEM, we have determined the structures of the Leishmania donovani and human ribosomes at 2.9 Å and 3.6 Å, respectively. Our structure of the leishmanial ribosome elucidates the organization of the six fragments of its large subunit rRNA (as opposed to a single 28S rRNA in most eukaryotes, including humans) and reveals atomic details of a unique 20 amino acid extension of the uL13 protein that pins down the ends of three of the rRNA fragments. The structure also fashions many large rRNA expansion segments. Direct comparison of our human and leishmanial ribosome structures at the decoding A-site sheds light on how the bacterial ribosome-targeting drug paromomycin selectively inhibits the eukaryotic L. donovani, but not human, ribosome.
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Affiliation(s)
- Xing Zhang
- Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- California NanoSystems Institute, University of California, Los Angeles, California 90095, USA
| | - Mason Lai
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Winston Chang
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Iris Yu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Ke Ding
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Jan Mrazek
- Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Hwee L. Ng
- Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Otto O. Yang
- California NanoSystems Institute, University of California, Los Angeles, California 90095, USA
- Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Dmitri A. Maslov
- Department of Biology, University of California, Riverside, California 91521, USA
| | - Z. Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles, California 90095, USA
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095, USA
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32
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Abstract
The sheer molecular scale of the ribosome is intimidating to the traditional drug designer. By analyzing the ribosome as a series of 12 key target sites, this review seeks to make the ribosome ligand design process more manageable. Analysis of recently evaluated ribosomal structures, particularly those with bound antibiotics, indicates where the ligand target sites are located. This review employs current research data to map antibiotic binding across the ribosome. A number of neighboring ligand-binding sites are often contiguous and can be combined. Ligands that bind in close proximity can be combined into hybrid structures. The different ways antibiotics disrupt ribosomal function are also discussed. Antibiotics tend to inhibit conformational changes that are essential to the ribosomal mechanism.
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33
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Dabrowski M, Bukowy-Bieryllo Z, Zietkiewicz E. Translational readthrough potential of natural termination codons in eucaryotes--The impact of RNA sequence. RNA Biol 2016; 12:950-8. [PMID: 26176195 PMCID: PMC4615788 DOI: 10.1080/15476286.2015.1068497] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Termination of protein synthesis is not 100% efficient. A number of natural mechanisms that suppress translation termination exist. One of them is STOP codon readthrough, the process that enables the ribosome to pass through the termination codon in mRNA and continue translation to the next STOP codon in the same reading frame. The efficiency of translational readthrough depends on a variety of factors, including the identity of the termination codon, the surrounding mRNA sequence context, and the presence of stimulating compounds. Understanding the interplay between these factors provides the necessary background for the efficient application of the STOP codon suppression approach in the therapy of diseases caused by the presence of premature termination codons.
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Affiliation(s)
- Maciej Dabrowski
- a Institute of Human Genetics; Polish Academy of Sciences ; Poznan , Poland
| | | | - Ewa Zietkiewicz
- a Institute of Human Genetics; Polish Academy of Sciences ; Poznan , Poland
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34
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Green L, Goff SP. Translational readthrough-promoting drugs enhance pseudoknot-mediated suppression of the stop codon at the Moloney murine leukemia virus gag–pol junction. J Gen Virol 2016; 96:3411-3421. [PMID: 26382736 DOI: 10.1099/jgv.0.000284] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Translational readthrough-promoting drugs enhance the incorporation of amino acids at stop codons and can thus bypass premature termination during protein synthesis. The polymerase (Pol) proteins of Moloney murine leukemia virus (MoMLV) are synthesized as a large Gag–Pol fusion protein, formed by the readthrough of a stop codon at the end of the gag ORF. The downstream pol ORF lacks its own start codon, and Pol protein synthesis is wholly dependent on translation of the upstream gag gene and the readthrough event for expression. Here, we explored the effects of readthrough-promoting drugs – aminoglycoside antibiotics and the small molecule ataluren – on the efficiency of readthrough of the stop codon in the context of the MoMLV genome. We showed that these compounds increased readthrough of the stop codon at the MoMLV gag–pol junction in vivo above the already high basal level and that the resulting elevated gag–pol readthrough had deleterious effects on virus replication. We also showed that readthrough efficiency could be driven to even higher levels in vitro, and that the combination of the small molecules and the RNA structure at the MoMLV stop codon could achieve extremely high readthrough efficiencies.
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Affiliation(s)
- Lisa Green
- Department of Biological Sciences, Columbia University Medical Center, New York, NY 10032, USA
| | - Stephen P Goff
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA.,Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA.,Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
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35
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Kisly I, Gulay SP, Mäeorg U, Dinman JD, Remme J, Tamm T. The Functional Role of eL19 and eB12 Intersubunit Bridge in the Eukaryotic Ribosome. J Mol Biol 2016; 428:2203-16. [PMID: 27038511 DOI: 10.1016/j.jmb.2016.03.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 12/12/2022]
Abstract
During translation, the two eukaryotic ribosomal subunits remain associated through 17 intersubunit bridges, five of which are eukaryote specific. These are mainly localized to the peripheral regions and are believed to stabilize the structure of the ribosome. The functional importance of these bridges remains largely unknown. Here, the essentiality of the eukaryote-specific bridge eB12 has been investigated. The main component of this bridge is ribosomal protein eL19 that is composed of an N-terminal globular domain, a middle region, and a long C-terminal α-helix. The analysis of deletion mutants demonstrated that the globular domain and middle region of eL19 are essential for cell viability, most likely functioning in ribosome assembly. The eB12 bridge, formed by contacts between the C-terminal α-helix of eL19 and 18S rRNA in concert with additional stabilizing interactions involving either eS7 or uS17, is dispensable for viability. Nevertheless, eL19 mutants impaired in eB12 bridge formation displayed slow growth phenotypes, altered sensitivity/resistance to translational inhibitors, and enhanced hyperosmotic stress tolerance. Biochemical analyses determined that the eB12 bridge contributes to the stability of ribosome subunit interactions in vitro. 60S subunits containing eL19 variants defective in eB12 bridge formation failed to form 80S ribosomes regardless of Mg(2+) concentration. The reassociation of 40S and mutant 60S subunits was markedly improved in the presence of deacetylated tRNA, emphasizing the importance of tRNAs during the subunit association. We propose that the eB12 bridge plays an important role in subunit joining and in optimizing ribosome functionality.
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Affiliation(s)
- Ivan Kisly
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Suna P Gulay
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, United States
| | - Uno Mäeorg
- Institute of Chemistry, University of Tartu, Tartu 50411, Estonia
| | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, United States
| | - Jaanus Remme
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia.
| | - Tiina Tamm
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia.
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36
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Huang CK, Shen YL, Huang LF, Wu SJ, Yeh CH, Lu CA. The DEAD-Box RNA Helicase AtRH7/PRH75 Participates in Pre-rRNA Processing, Plant Development and Cold Tolerance in Arabidopsis. PLANT & CELL PHYSIOLOGY 2016; 57:174-91. [PMID: 26637537 DOI: 10.1093/pcp/pcv188] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 11/18/2015] [Indexed: 05/18/2023]
Abstract
DEAD-box RNA helicases belong to an RNA helicase family that plays specific roles in various RNA metabolism processes, including ribosome biogenesis, mRNA splicing, RNA export, mRNA translation and RNA decay. This study investigated a DEAD-box RNA helicase, AtRH7/PRH75, in Arabidopsis. Expression of AtRH7/PRH75 was ubiquitous; however, the levels of mRNA accumulation were increased in cell division regions and were induced by cold stress. The phenotypes of two allelic AtRH7/PRH75-knockout mutants, atrh7-2 and atrh7-3, resembled auxin-related developmental defects that were exhibited in several ribosomal protein mutants, and were more severe under cold stress. Northern blot and circular reverse transcription-PCR (RT-PCR) analyses indicated that unprocessed 18S pre-rRNAs accumulated in the atrh7 mutants. The atrh7 mutants were hyposensitive to the antibiotic streptomycin, which targets ribosomal small subunits, suggesting that AtRH7 was also involved in ribosome assembly. In addition, the atrh7-2 and atrh7-3 mutants displayed cold hypersensitivity and decreased expression of CBF1, CBF2 and CBF3, which might be responsible for the cold intolerance. The present study indicated that AtRH7 participates in rRNA biogenesis and is also involved in plant development and cold tolerance in Arabidopsis.
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Affiliation(s)
- Chun-Kai Huang
- Department of Life Sciences, National Central University, Jhongli City, Taoyuan County 320, Taiwan, ROC These authors contributed equally to this work
| | - Yu-Lien Shen
- Department of Life Sciences, National Central University, Jhongli City, Taoyuan County 320, Taiwan, ROC These authors contributed equally to this work
| | - Li-Fen Huang
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Jhongli City, Taoyuan County 320, Taiwan, ROC
| | - Shaw-Jye Wu
- Department of Life Sciences, National Central University, Jhongli City, Taoyuan County 320, Taiwan, ROC
| | - Chin-Hui Yeh
- Department of Life Sciences, National Central University, Jhongli City, Taoyuan County 320, Taiwan, ROC
| | - Chung-An Lu
- Department of Life Sciences, National Central University, Jhongli City, Taoyuan County 320, Taiwan, ROC
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37
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Caspi M, Firsow A, Rajkumar R, Skalka N, Moshkovitz I, Munitz A, Pasmanik-Chor M, Greif H, Megido D, Kariv R, Rosenberg DW, Rosin-Arbesfeld R. A flow cytometry-based reporter assay identifies macrolide antibiotics as nonsense mutation read-through agents. J Mol Med (Berl) 2015; 94:469-82. [PMID: 26620677 DOI: 10.1007/s00109-015-1364-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/24/2015] [Accepted: 11/03/2015] [Indexed: 01/01/2023]
Abstract
UNLABELLED A large number of human diseases are caused by nonsense mutations. These mutations result in premature protein termination and the expression of truncated, usually nonfunctional products. A promising therapeutic strategy for patients suffering from premature termination codon (PTC)-mediated disorders is to suppress the nonsense mutation and restore the expression of the affected protein. Such a suppression approach using specific antibiotics and other read-through promoting agents has been shown to suppress PTCs and restore the production of several important proteins. Here, we report the establishment of a novel, rapid, and very efficient method for screening stop-codon read-through agents. We also show that, in both mammalian cells and in a transgenic mouse model, distinct members of the macrolide antibiotic family can induce read-through of disease-causing stop codons leading to re-expression of several key proteins and to reduced disease phenotypes. Taken together, our results may help in the identification and characterization of well-needed customized pharmaceutical PTC suppression agents. KEY MESSAGES Establishment of a flow cytometry-based reporter assay to identify nonsense mutation read-through agents. Macrolide antibiotics can induce read-through of disease-causing stop codons. Macrolide-induced protein restoration can alleviate disease-like phenotypes.
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Affiliation(s)
- Michal Caspi
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Anastasia Firsow
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Raja Rajkumar
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Nir Skalka
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Itay Moshkovitz
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Ariel Munitz
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, G.S.W. Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
| | | | | | - Revital Kariv
- Department of Gastroenterology, Tel Aviv Sourasky Medical Center, Tel Aviv, 64239, Israel
| | - Daniel W Rosenberg
- Center for Molecular Medicine, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel.
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38
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Moreno-Martinez E, Vallieres C, Holland SL, Avery SV. Novel, Synergistic Antifungal Combinations that Target Translation Fidelity. Sci Rep 2015; 5:16700. [PMID: 26573415 PMCID: PMC4648087 DOI: 10.1038/srep16700] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/19/2015] [Indexed: 11/23/2022] Open
Abstract
There is an unmet need for new antifungal or fungicide treatments, as resistance to existing treatments grows. Combination treatments help to combat resistance. Here we develop a novel, effective target for combination antifungal therapy. Different aminoglycoside antibiotics combined with different sulphate-transport inhibitors produced strong, synergistic growth-inhibition of several fungi. Combinations decreased the respective MICs by ≥8-fold. Synergy was suppressed in yeast mutants resistant to effects of sulphate-mimetics (like chromate or molybdate) on sulphate transport. By different mechanisms, aminoglycosides and inhibition of sulphate transport cause errors in mRNA translation. The mistranslation rate was stimulated up to 10-fold when the agents were used in combination, consistent with this being the mode of synergistic action. A range of undesirable fungi were susceptible to synergistic inhibition by the combinations, including the human pathogens Candida albicans, C. glabrata and Cryptococcus neoformans, the food spoilage organism Zygosaccharomyces bailii and the phytopathogens Rhizoctonia solani and Zymoseptoria tritici. There was some specificity as certain fungi were unaffected. There was no synergy against bacterial or mammalian cells. The results indicate that translation fidelity is a promising new target for combinatorial treatment of undesirable fungi, the combinations requiring substantially decreased doses of active components compared to each agent alone.
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Affiliation(s)
- Elena Moreno-Martinez
- School of Life Sciences, University of Nottingham University Park, Nottingham NG7 2RD, UK
| | - Cindy Vallieres
- School of Life Sciences, University of Nottingham University Park, Nottingham NG7 2RD, UK
| | - Sara L Holland
- School of Life Sciences, University of Nottingham University Park, Nottingham NG7 2RD, UK
| | - Simon V Avery
- School of Life Sciences, University of Nottingham University Park, Nottingham NG7 2RD, UK
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Saito K, Ito K. Genetic analysis of L123 of the tRNA-mimicking eukaryote release factor eRF1, an amino acid residue critical for discrimination of stop codons. Nucleic Acids Res 2015; 43:4591-601. [PMID: 25897120 PMCID: PMC4482090 DOI: 10.1093/nar/gkv376] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/09/2015] [Indexed: 11/18/2022] Open
Abstract
In eukaryotes, the tRNA-mimicking polypeptide-chain release factor, eRF1, decodes stop codons on the ribosome in a complex with eRF3; this complex exhibits striking structural similarity to the tRNA–eEF1A–GTP complex. Although amino acid residues or motifs of eRF1 that are critical for stop codon discrimination have been identified, the details of the molecular mechanisms involved in the function of the ribosomal decoding site remain obscure. Here, we report analyses of the position-123 amino acid of eRF1 (L123 in Saccharomyces cerevisiae eRF1), a residue that is phylogenetically conserved among species with canonical and variant genetic codes. In vivo readthrough efficiency analysis and genetic growth complementation analysis of the residue-123 systematic mutants suggested that this amino acid functions in stop codon discrimination in a manner coupled with eRF3 binding, and distinctive from previously reported adjacent residues. Furthermore, aminoglycoside antibiotic sensitivity analysis and ribosomal docking modeling of eRF1 in a quasi-A/T state suggested a functional interaction between the side chain of L123 and ribosomal residues critical for codon recognition in the decoding site, as a molecular explanation for coupling with eRF3. Our results provide insights into the molecular mechanisms underlying stop codon discrimination by a tRNA-mimicking protein on the ribosome.
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Affiliation(s)
- Kazuki Saito
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan
| | - Koichi Ito
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan
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40
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Oren YS, McClure ML, Rowe SM, Sorscher EJ, Bester AC, Manor M, Kerem E, Rivlin J, Zahdeh F, Mann M, Geiger T, Kerem B. The unfolded protein response affects readthrough of premature termination codons. EMBO Mol Med 2014; 6:685-701. [PMID: 24705877 PMCID: PMC4023889 DOI: 10.1002/emmm.201303347] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
One-third of monogenic inherited diseases result from premature termination codons (PTCs). Readthrough of in-frame PTCs enables synthesis of full-length functional proteins. However, extended variability in the response to readthrough treatment is found among patients, which correlates with the level of nonsense transcripts. Here, we aimed to reveal cellular pathways affecting this inter-patient variability. We show that activation of the unfolded protein response (UPR) governs the response to readthrough treatment by regulating the levels of transcripts carrying PTCs. Quantitative proteomic analyses showed substantial differences in UPR activation between patients carrying PTCs, correlating with their response. We further found a significant inverse correlation between the UPR and nonsense-mediated mRNA decay (NMD), suggesting a feedback loop between these homeostatic pathways. We uncovered and characterized the mechanism underlying this NMD-UPR feedback loop, which augments both UPR activation and NMD attenuation. Importantly, this feedback loop enhances the response to readthrough treatment, highlighting its clinical importance. Altogether, our study demonstrates the importance of the UPR and its regulatory network for genetic diseases caused by PTCs and for cell homeostasis under normal conditions.
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Affiliation(s)
- Yifat S Oren
- Department of Genetics, The Hebrew University, Jerusalem, Israel
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41
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Damon JR, Pincus D, Ploegh HL. tRNA thiolation links translation to stress responses in Saccharomyces cerevisiae. Mol Biol Cell 2014; 26:270-82. [PMID: 25392298 PMCID: PMC4294674 DOI: 10.1091/mbc.e14-06-1145] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The URM1 pathway functions in a tRNA thiolation reaction that is required for synthesis of the mcm5s2U34 nucleoside found in tRNAs. Growth of Saccharomyces cerevisiae cells at an elevated temperature results in altered levels of modification enzymes, and this leads to decreased levels of tRNA thiolation. tRNA thiolation is tied to cellular stress responses. Although tRNA modifications have been well catalogued, the precise functions of many modifications and their roles in mediating gene expression are still being elucidated. Whereas tRNA modifications were long assumed to be constitutive, it is now apparent that the modification status of tRNAs changes in response to different environmental conditions. The URM1 pathway is required for thiolation of the cytoplasmic tRNAs tGluUUC, tGlnUUG, and tLysUUU in Saccharomyces cerevisiae. We demonstrate that URM1 pathway mutants have impaired translation, which results in increased basal activation of the Hsf1-mediated heat shock response; we also find that tRNA thiolation levels in wild-type cells decrease when cells are grown at elevated temperature. We show that defects in tRNA thiolation can be conditionally advantageous, conferring resistance to endoplasmic reticulum stress. URM1 pathway proteins are unstable and hence are more sensitive to changes in the translational capacity of cells, which is decreased in cells experiencing stresses. We propose a model in which a stress-induced decrease in translation results in decreased levels of URM1 pathway components, which results in decreased tRNA thiolation levels, which further serves to decrease translation. This mechanism ensures that tRNA thiolation and translation are tightly coupled and coregulated according to need.
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Affiliation(s)
- Jadyn R Damon
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - David Pincus
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Hidde L Ploegh
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
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42
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Duscha S, Boukari H, Shcherbakov D, Salian S, Silva S, Kendall A, Kato T, Akbergenov R, Perez-Fernandez D, Bernet B, Vaddi S, Thommes P, Schacht J, Crich D, Vasella A, Böttger EC. Identification and evaluation of improved 4'-O-(alkyl) 4,5-disubstituted 2-deoxystreptamines as next-generation aminoglycoside antibiotics. mBio 2014; 5:e01827-14. [PMID: 25271289 PMCID: PMC4196235 DOI: 10.1128/mbio.01827-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 08/29/2014] [Indexed: 01/15/2023] Open
Abstract
UNLABELLED The emerging epidemic of drug resistance places the development of efficacious and safe antibiotics in the spotlight of current research. Here, we report the design of next-generation aminoglycosides. Discovery efforts were driven by rational synthesis focusing on 4' alkylations of the aminoglycoside paromomycin, with the goal to alleviate the most severe and disabling side effect of aminoglycosides-irreversible hearing loss. Compounds were evaluated for target activity in in vitro ribosomal translation assays, antibacterial potency against selected pathogens, cytotoxicity against mammalian cells, and in vivo ototoxicity. The results of this study produced potent compounds with excellent selectivity at the ribosomal target, promising antibacterial activity, and little, if any, ototoxicity upon chronic administration. The favorable biocompatibility profile combined with the promising antibacterial activity emphasizes the potential of next-generation aminoglycosides in the treatment of infectious diseases without the risk of ototoxicity. IMPORTANCE The ever-widening epidemic of multidrug-resistant infectious diseases and the paucity of novel antibacterial agents emerging from modern screening platforms mandate the reinvestigation of established drugs with an emphasis on improved biocompatibility and overcoming resistance mechanisms. Here, we describe the preparation and evaluation of derivatives of the established aminoglycoside antibiotic paromomycin that effectively remove its biggest deficiency, ototoxicity, and overcome certain bacterial resistance mechanisms.
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Affiliation(s)
- Stefan Duscha
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Heithem Boukari
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Dimitri Shcherbakov
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Sumantha Salian
- Laboratorium für Organische Chemie, ETH Zürich, Zürich, Switzerland
| | - Sandrina Silva
- Laboratorium für Organische Chemie, ETH Zürich, Zürich, Switzerland
| | - Ann Kendall
- Department of Otolaryngology, Kresge Hearing Research Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Takayuki Kato
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Rashid Akbergenov
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | | | - Bruno Bernet
- Laboratorium für Organische Chemie, ETH Zürich, Zürich, Switzerland
| | | | - Pia Thommes
- Euprotec Limited, Manchester, United Kingdom
| | - Jochen Schacht
- Department of Otolaryngology, Kresge Hearing Research Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - David Crich
- Department of Chemistry, Wayne State University, Detroit, Michigan, USA
| | - Andrea Vasella
- Laboratorium für Organische Chemie, ETH Zürich, Zürich, Switzerland
| | - Erik C. Böttger
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
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43
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Structural basis for the inhibition of the eukaryotic ribosome. Nature 2014; 513:517-22. [DOI: 10.1038/nature13737] [Citation(s) in RCA: 349] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/06/2014] [Indexed: 11/08/2022]
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44
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Circular code motifs in the ribosome decoding center. Comput Biol Chem 2014; 52:9-17. [PMID: 25215650 DOI: 10.1016/j.compbiolchem.2014.08.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 08/01/2014] [Accepted: 08/01/2014] [Indexed: 11/20/2022]
Abstract
A translation (framing) code based on the circular code was proposed in Michel (2012) with the identification of X circular code motifs (X motifs shortly) in the bacterial rRNA of Thermus thermophilus, in particular in the ribosome decoding center. Three classes of X motifs are now identified in the rRNAs of bacteria Escherichia coli and Thermus thermophilus, archaea Pyrococcus furiosus, nuclear eukaryotes Saccharomyces cerevisiae, Triticum aestivum and Homo sapiens, and chloroplast Spinacia oleracea. The universally conserved nucleotides A1492 and A1493 in all studied rRNAs (bacteria, archaea, nuclear eukaryotes, and chloroplasts) belong to X motifs (called mAA). The conserved nucleotide G530 in rRNAs of bacteria and archaea belongs to X motifs (called mG). Furthermore, the X motif mG is also found in rRNAs of nuclear eukaryotes and chloroplasts. Finally, a potentially important X motif, called m, is identified in all studied rRNAs. With the available crystallographic structures of the Protein Data Bank PDB, we also show that these X motifs mAA, mG, and m belong to the ribosome decoding center of all studied rRNAs with possible interaction with the mRNA X motifs and the tRNA X motifs. The three classes of X motifs identified here in rRNAs of several and different organisms strengthen the concept of translation code based on the circular code.
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45
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Karijolich J, Yu YT. Therapeutic suppression of premature termination codons: mechanisms and clinical considerations (review). Int J Mol Med 2014; 34:355-62. [PMID: 24939317 PMCID: PMC4094583 DOI: 10.3892/ijmm.2014.1809] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 06/06/2014] [Indexed: 12/22/2022] Open
Abstract
An estimated one-third of genetic disorders are the result of mutations that generate premature termination codons (PTCs) within protein coding genes. These disorders are phenotypically diverse and consist of diseases that affect both young and old individuals. Various small molecules have been identified that are capable of modulating the efficiency of translation termination, including select antibiotics of the aminoglycoside family and multiple novel synthetic molecules, including PTC124. Several of these agents have proved their effectiveness at promoting nonsense suppression in preclinical animal models, as well as in clinical trials. In addition, it has recently been shown that box H/ACA RNA-guided peudouridylation, when directed to modify PTCs, can also promote nonsense suppression. In this review, we summarize our current understanding of eukaryotic translation termination and discuss various methods for promoting the read-through of disease-causing PTCs, as well as the current obstacles that stand in the way of using the discussed agents broadly in clinical practice.
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Affiliation(s)
- John Karijolich
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Yi-Tao Yu
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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46
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Perez-Fernandez D, Shcherbakov D, Matt T, Leong NC, Kudyba I, Duscha S, Boukari H, Patak R, Dubbaka SR, Lang K, Meyer M, Akbergenov R, Freihofer P, Vaddi S, Thommes P, Ramakrishnan V, Vasella A, Böttger EC. 4'-O-substitutions determine selectivity of aminoglycoside antibiotics. Nat Commun 2014; 5:3112. [PMID: 24473108 PMCID: PMC3942853 DOI: 10.1038/ncomms4112] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 12/16/2013] [Indexed: 02/04/2023] Open
Abstract
Clinical use of 2-deoxystreptamine aminoglycoside antibiotics, which target the bacterial ribosome, is compromised by adverse effects related to limited drug selectivity. Here we present a series of 4',6'-O-acetal and 4'-O-ether modifications on glucopyranosyl ring I of aminoglycosides. Chemical modifications were guided by measuring interactions between the compounds synthesized and ribosomes harbouring single point mutations in the drug-binding site, resulting in aminoglycosides that interact poorly with the drug-binding pocket of eukaryotic mitochondrial or cytosolic ribosomes. Yet, these compounds largely retain their inhibitory activity for bacterial ribosomes and show antibacterial activity. Our data indicate that 4'-O-substituted aminoglycosides possess increased selectivity towards bacterial ribosomes and little activity for any of the human drug-binding pockets.
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Affiliation(s)
- Déborah Perez-Fernandez
- Laboratorium für Organische Chemie, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
- These authors contributed equally to this work
| | - Dmitri Shcherbakov
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
- These authors contributed equally to this work
| | - Tanja Matt
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Ng Chyan Leong
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia
- These authors contributed equally to this work
| | - Iwona Kudyba
- Laboratorium für Organische Chemie, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Stefan Duscha
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Heithem Boukari
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Rashmi Patak
- Laboratorium für Organische Chemie, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Srinivas Reddy Dubbaka
- Laboratorium für Organische Chemie, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Kathrin Lang
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Martin Meyer
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Rashid Akbergenov
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Pietro Freihofer
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
| | - Swapna Vaddi
- Euprotec Limited, Unit 12 Williams House, Manchester Science Park, Lloyd Street North, Manchester M15 6SE, UK
| | - Pia Thommes
- Euprotec Limited, Unit 12 Williams House, Manchester Science Park, Lloyd Street North, Manchester M15 6SE, UK
| | - V. Ramakrishnan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Andrea Vasella
- Laboratorium für Organische Chemie, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Erik C. Böttger
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, 8006 Zürich, Switzerland
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47
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He X, Zhu X, Wang X, Wang W, Dai Y, Yan Q. Nuclear modifier MTO2 modulates the aminoglycoside-sensitivity of mitochondrial 15S rRNA C1477G mutation in Saccharomyces cerevisiae. PLoS One 2013; 8:e81490. [PMID: 24339937 PMCID: PMC3858254 DOI: 10.1371/journal.pone.0081490] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 10/14/2013] [Indexed: 12/23/2022] Open
Abstract
The phenotypic manifestations of mitochondrial DNA (mtDNA) mutations are modulated by mitochondrial DNA haplotypes, nuclear modifier genes and environmental factors. The yeast mitochondrial 15S rRNA C1477G (PR or PR454) mutation corresponds to the human 12S rRNA C1494T and A1555G mutations, which are well known as primary factors for aminoglycoside-induced nonsyndromic deafness. Here we report that the deletion of the nuclear modifier gene MTO2 suppressed the aminoglycoside-sensitivity of mitochondrial 15S rRNA C1477G mutation in Saccharomyces cerevisiae. First, the strain with a single mtDNA C1477G mutation exhibited hypersensitivity to neomycin. Functional assays indicated that the steady-state transcription level of mitochondrial DNA, the mitochondrial respiratory rate, and the membrane potential decreased significantly after neomycin treatment. The impaired mitochondria could not produce sufficient energy to maintain cell viability. Second, when the mto2 null and the mitochondrial C1477G mutations co-existed (mto2(PR)), the oxygen consumption rate in the double mutant decreased markedly compared to that of the control strains (MTO2(PS), mto2(PS) and MTO2(PR)). The expression levels of the key glycolytic genes HXK2, PFK1 and PYK1 in the mto2(PR) strain were stimulated by neomycin and up-regulated by 89%, 112% and 55%, respectively. The enhanced glycolysis compensated for the respiratory energy deficits, and could be inhibited by the glycolytic enzyme inhibitor. Our findings in yeast will provide a new insight into the pathogenesis of human deafness.
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Affiliation(s)
- Xiangyu He
- College of Life Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoyu Zhu
- College of Life Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xuexiang Wang
- College of Life Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wei Wang
- College of Life Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yu Dai
- College of Life Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qingfeng Yan
- College of Life Science, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail:
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48
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Letzring DP, Wolf AS, Brule CE, Grayhack EJ. Translation of CGA codon repeats in yeast involves quality control components and ribosomal protein L1. RNA (NEW YORK, N.Y.) 2013; 19:1208-17. [PMID: 23825054 PMCID: PMC3753928 DOI: 10.1261/rna.039446.113] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Translation of CGA codon repeats in the yeast Saccharomyces cerevisiae is inefficient, resulting in dose-dependent reduction in expression and in production of an mRNA cleavage product, indicative of a stalled ribosome. Here, we use genetics and translation inhibitors to understand how ribosomes respond to CGA repeats. We find that CGA codon repeats result in a truncated polypeptide that is targeted for degradation by Ltn1, an E3 ubiquitin ligase involved in nonstop decay, although deletion of LTN1 does not improve expression downstream from CGA repeats. Expression downstream from CGA codons at residue 318, but not at residue 4, is improved by deletion of either ASC1 or HEL2, previously implicated in inhibition of translation by polybasic sequences. Thus, translation of CGA repeats likely causes ribosomes to stall and exploits known quality control systems. Expression downstream from CGA repeats at amino acid 4 is improved by paromomycin, an aminoglycoside that relaxes decoding specificity. Paromomycin has no effect if native tRNA(Arg(ICG)) is highly expressed, consistent with the idea that failure to efficiently decode CGA codons might occur in part due to rejection of the cognate tRNA(Arg(ICG)). Furthermore, expression downstream from CGA repeats is improved by inactivation of RPL1B, one of two genes encoding the universally conserved ribosomal protein L1. The effects of rpl1b-Δ and of either paromomycin or tRNA(Arg(ICG)) on CGA decoding are additive, suggesting that the rpl1b-Δ mutant suppresses CGA inhibition by means other than increased acceptance of tRNA(Arg(ICG)). Thus, inefficient decoding of CGA likely involves at least two independent defects in translation.
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Affiliation(s)
- Daniel P. Letzring
- Department of Biochemistry and Biophysics, University of Rochester Medical School, Rochester, New York 14642, USA
| | - Andrew S. Wolf
- Department of Biochemistry and Biophysics, University of Rochester Medical School, Rochester, New York 14642, USA
| | - Christina E. Brule
- Department of Biochemistry and Biophysics, University of Rochester Medical School, Rochester, New York 14642, USA
| | - Elizabeth J. Grayhack
- Department of Biochemistry and Biophysics, University of Rochester Medical School, Rochester, New York 14642, USA
- Corresponding authorE-mail
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49
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First description of heterogeneity in 18S rRNA genes in the haploid genome of Cryptosporidium andersoni Kawatabi type. Vet Parasitol 2013; 196:220-4. [DOI: 10.1016/j.vetpar.2012.12.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 12/25/2012] [Accepted: 12/26/2012] [Indexed: 11/21/2022]
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50
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Mahto SK, Chow CS. Probing the stabilizing effects of modified nucleotides in the bacterial decoding region of 16S ribosomal RNA. Bioorg Med Chem 2013; 21:2720-6. [PMID: 23566761 DOI: 10.1016/j.bmc.2013.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/03/2013] [Accepted: 03/07/2013] [Indexed: 10/27/2022]
Abstract
The bacterial decoding region of 16S ribosomal RNA has multiple modified nucleotides. In order to study the role of N(4),2'-O-dimethylcytidine (m(4)Cm), the corresponding phosphoramidite was synthesized utilizing 5'-silyl-2'-ACE chemistry. Using solid-phase synthesis, m(4)Cm, 5-methylcytidine (m(5)C), 3-methyluridine (m(3)U), and 2'-O-methylcytidine (Cm) were site-specifically incorporated into small RNAs representing the decoding regions of different bacterial species. Biophysical studies were then used to provide insight into the stabilizing roles of the modified nucleotides. These studies reveal that methylation of cytidine and uridine has different effects. The same modifications at different positions or sequence contexts within similar RNA constructs also have contrasting roles, such as stabilizing or destabilizing the RNA helix.
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Affiliation(s)
- Santosh K Mahto
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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