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Lebeda D, Fierenz A, Werfel L, Rosin-Arbesfeld R, Hofhuis J, Thoms S. Systematic and quantitative analysis of stop codon readthrough in Rett syndrome nonsense mutations. J Mol Med (Berl) 2024; 102:641-653. [PMID: 38430393 PMCID: PMC11055764 DOI: 10.1007/s00109-024-02436-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/16/2024] [Accepted: 02/20/2024] [Indexed: 03/03/2024]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder resulting from genetic mutations in the methyl CpG binding protein 2 (MeCP2) gene. Specifically, around 35% of RTT patients harbor premature termination codons (PTCs) within the MeCP2 gene due to nonsense mutations. A promising therapeutic avenue for these individuals involves the use of aminoglycosides, which stimulate translational readthrough (TR) by causing stop codons to be interpreted as sense codons. However, the effectiveness of this treatment depends on several factors, including the type of stop codon and the surrounding nucleotides, collectively referred to as the stop codon context (SCC). Here, we develop a high-content reporter system to precisely measure TR efficiency at different SCCs, assess the recovery of the full-length MeCP2 protein, and evaluate its subcellular localization. We have conducted a comprehensive investigation into the intricate relationship between SCC characteristics and TR induction, examining a total of 14 pathogenic MeCP2 nonsense mutations with the aim to advance the prospects of personalized therapy for individuals with RTT. Our results demonstrate that TR induction can successfully restore full-length MeCP2 protein, albeit to varying degrees, contingent upon the SCC and the specific position of the PTC within the MeCP2 mRNA. TR induction can lead to the re-establishment of nuclear localization of MeCP2, indicating the potential restoration of protein functionality. In summary, our findings underscore the significance of SCC-specific approaches in the development of tailored therapies for RTT. By unraveling the relationship between SCC and TR therapy, we pave the way for personalized, individualized treatment strategies that hold promise for improving the lives of individuals affected by this debilitating neurodevelopmental disorder. KEY MESSAGES: The efficiency of readthrough induction at MeCP2 premature termination codons strongly depends on the stop codon context. The position of the premature termination codon on the transcript influences the readthrough inducibility. A new high-content dual reporter assay facilitates the measurement and prediction of readthrough efficiency of specific nucleotide stop contexts. Readthrough induction results in the recovery of full-length MeCP2 and its re-localization to the nucleus. MeCP2 requires only one of its annotated nuclear localization signals.
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Affiliation(s)
- Dennis Lebeda
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Adrian Fierenz
- Department of Child and Adolescent Health, University Medical Center Göttingen, Göttingen, Germany
| | - Lina Werfel
- Department of Child and Adolescent Health, University Medical Center Göttingen, Göttingen, Germany
- Present Address: Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Julia Hofhuis
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Sven Thoms
- Department for Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany.
- Department of Child and Adolescent Health, University Medical Center Göttingen, Göttingen, Germany.
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2
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Torices L, Nunes-Xavier CE, Mingo J, Luna S, Erramuzpe A, Cortés JM, Pulido R. Induction of Translational Readthrough on Protein Tyrosine Phosphatases Targeted by Premature Termination Codon Mutations in Human Disease. Methods Mol Biol 2024; 2743:1-19. [PMID: 38147205 DOI: 10.1007/978-1-0716-3569-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Nonsense mutations generating premature termination codons (PTCs) in various genes are frequently associated with somatic cancer and hereditary human diseases since PTCs commonly generate truncated proteins with defective or altered function. Induced translational readthrough during protein biosynthesis facilitates the incorporation of an amino acid at the position of a PTC, allowing the synthesis of a complete protein. This may evade the pathological effect of the PTC mutation and provide new therapeutic opportunities. Several protein tyrosine phosphatases (PTPs) genes are targeted by PTC in human disease, the tumor suppressor PTEN being the more prominent paradigm. Here, using PTEN and laforin as examples, two PTPs from the dual-specificity phosphatase subfamily, we describe methodologies to analyze in silico the distribution and frequency of pathogenic PTC in PTP genes. We also summarize laboratory protocols and technical notes to study the induced translational readthrough reconstitution of the synthesis of PTP targeted by PTC in association with disease in cellular models.
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Affiliation(s)
- Leire Torices
- Biobizkaia Health Research Institute, Barakaldo, Spain
| | - Caroline E Nunes-Xavier
- Biobizkaia Health Research Institute, Barakaldo, Spain
- Institute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital, Oslo, Norway
| | - Janire Mingo
- Biobizkaia Health Research Institute, Barakaldo, Spain
| | - Sandra Luna
- Biobizkaia Health Research Institute, Barakaldo, Spain
| | - Asier Erramuzpe
- Biobizkaia Health Research Institute, Barakaldo, Spain
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
| | - Jesús M Cortés
- Biobizkaia Health Research Institute, Barakaldo, Spain
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
- Cell Biology and Histology Department, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Rafael Pulido
- Biobizkaia Health Research Institute, Barakaldo, Spain.
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain.
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3
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Beryozkin A, Nagel-Wolfum K, Banin E, Sharon D. Factors Affecting Readthrough of Natural Versus Premature Termination Codons. Adv Exp Med Biol 2023; 1415:149-155. [PMID: 37440028 DOI: 10.1007/978-3-031-27681-1_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Nonsense mutations occur within the open-reading frame of a gene resulting in a premature termination codon (PTC). PTC-containing mRNAs can either be degeraded or cause premature translation termination producing a truncated protein that can be either nonfunctional or toxic. Translational readthrough inducing drugs (TRIDs) are small molecules that are able to induce readthrough, resulting in the restoration of full-length protein expression. The re-expressed proteins usually harbor a missense change. The effciency of individual TRIDs is variable and varies between different genes and even different nonsense mutations in the same gene. This review summarizes factors, including the sequences located upstream and downstream the disease-causing mutation and the type of PTC, affecting the translational readthrough process by modulating the type of amino acid insertion and the efficiency of the process during readthrough following TRIDs treatments.
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Affiliation(s)
- Avigail Beryozkin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Kerstin Nagel-Wolfum
- Institute of Molecular Physiology & Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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4
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Del Toro N, Lessard F, Bouchard J, Mobasheri N, Guillon J, Igelmann S, Tardif S, Buffard T, Bourdeau V, Brakier-Gingras L, Ferbeyre G. Cellular Senescence limits Translational Readthrough. Biol Open 2021; 10:272574. [PMID: 34676390 PMCID: PMC8649927 DOI: 10.1242/bio.058688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 10/14/2021] [Indexed: 11/20/2022] Open
Abstract
The origin and evolution of cancer cells is considered to be mainly fueled by DNA mutations. Although translation errors could also expand the cellular proteome, their role in cancer biology remains poorly understood. Tumor suppressors called caretakers block cancer initiation and progression by preventing DNA mutations and/or stimulating DNA repair. If translational errors contribute to tumorigenesis, then caretaker genes should prevent such errors in normal cells in response to oncogenic stimuli. Here, we show that the process of cellular senescence induced by oncogenes, tumor suppressors or chemotherapeutic drugs is associated with a reduction in translational readthrough (TR) measured using reporters containing termination codons withing the context of both normal translation termination or programmed TR. Senescence reduced both basal TR and TR stimulated by aminoglycosides. Mechanistically, the reduction of TR during senescence is controlled by the RB tumor suppressor pathway. Cells that escape from cellular senescence either induced by oncogenes or chemotherapy have an increased TR. Also, breast cancer cells that escape from therapy-induced senescence express high levels of AGO1x, a TR isoform of AGO1 linked to breast cancer progression. We propose that senescence and the RB pathway reduce TR limiting proteome diversity and the expression of TR proteins required for cancer cell proliferation. Summary: We report that senescence and the RB pathway reduce translational readthrough (TR) limiting proteome diversity and the expression of TR proteins such as Ago1X required for cancer cell proliferation.
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Affiliation(s)
- Neylen Del Toro
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Frédéric Lessard
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Jacob Bouchard
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Nasrin Mobasheri
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Jordan Guillon
- CRCHUM, 900 Saint-Denis, bureau R10.432, Montréal, Québec, H2X 0A9, Canada
| | - Sebastian Igelmann
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada.,CRCHUM, 900 Saint-Denis, bureau R10.432, Montréal, Québec, H2X 0A9, Canada
| | - Sarah Tardif
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Tony Buffard
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Véronique Bourdeau
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Léa Brakier-Gingras
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
| | - Gerardo Ferbeyre
- Département de Biochimie et Médecine Moléculaire, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada.,CRCHUM, 900 Saint-Denis, bureau R10.432, Montréal, Québec, H2X 0A9, Canada
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5
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Torices L, de las Heras J, Arango-Lasprilla JC, Cortés JM, Nunes-Xavier CE, Pulido R. MMADHC premature termination codons in the pathogenesis of cobalamin D disorder: Potential of translational readthrough reconstitution. Mol Genet Metab Rep 2021; 26:100710. [PMID: 33552904 PMCID: PMC7847965 DOI: 10.1016/j.ymgmr.2021.100710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 11/21/2022] Open
Abstract
Mutations in the MMADHC gene cause cobalamin D disorder (cblD), an autosomal recessive inborn disease with defects in intracellular cobalamin (cbl, vitamin B12) metabolism. CblD patients present methylmalonic aciduria (MMA), homocystinuria (HC), or combined MMA/HC, and usually suffer developmental delay and cognitive deficits. The most frequent MMADHC genetic alterations associated with disease generate MMADHC truncated proteins, in many cases due to mutations that create premature termination codons (PTC). In this study, we have performed a comprehensive and global characterization of MMADHC protein variants generated by all annotated MMADHC PTC mutations in cblD patients, and analyzed the potential of inducible translational PTC readthrough to reconstitute MMADHC biosynthesis. MMADHC protein truncation caused by disease-associated PTC differentially affected the alternative usage of translation initiation sites, protein abundance, and subcellular localization of MMADHC. Aminoglycoside compounds induced translational PTC readthrough of MMADHC truncated variants, allowing the biosynthesis of full-length MMADHC in a PTC-specific manner. Our results suggest that translational PTC readthrough-based interventions could complement current therapies for cblD patients carrying specific MMADHC PTC mutations.
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Affiliation(s)
- Leire Torices
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Javier de las Heras
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Division of Pediatric Metabolism (CIBER-ER), Cruces University Hospital, Barakaldo, Spain
- Department of Pediatrics, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Juan Carlos Arango-Lasprilla
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Cell Biology and Histology, University of the Basque Country (UPV/EHU), Leioa, Spain
- Ikerbasque, The Basque Foundation for Science, 48013 Bilbao, Spain
| | - Jesús M. Cortés
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Cell Biology and Histology, University of the Basque Country (UPV/EHU), Leioa, Spain
- Ikerbasque, The Basque Foundation for Science, 48013 Bilbao, Spain
| | - Caroline E. Nunes-Xavier
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Institute of Cancer Research, Oslo University Hospital Radiumhospitalet, N-0424 Oslo, Norway
| | - Rafael Pulido
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Ikerbasque, The Basque Foundation for Science, 48013 Bilbao, Spain
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6
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Tokhmafshan F, Dickinson K, Akpa MM, Brasell E, Huertas P, Goodyer PR. A no-nonsense approach to hereditary kidney disease. Pediatr Nephrol 2020; 35:2031-2042. [PMID: 31807928 DOI: 10.1007/s00467-019-04394-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/05/2019] [Accepted: 10/07/2019] [Indexed: 01/12/2023]
Abstract
The advent of a new class of aminoglycosides with increased translational readthrough of nonsense mutations and reduced toxicity offers a new therapeutic strategy for a subset of patients with hereditary kidney disease. The renal uptake and retention of aminoglycosides at a high intracellular concentration makes the kidney an ideal target for this approach. In this review, we explore the potential of aminoglycoside readthrough therapy in a number of hereditary kidney diseases and discuss the therapeutic window of opportunity for subclasses of each disease, when caused by nonsense mutations.
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Affiliation(s)
- Fatima Tokhmafshan
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada
| | - Kyle Dickinson
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada.,Department of Experimental Medicine, McGill University, Montreal, Canada
| | - Murielle M Akpa
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada
| | - Emma Brasell
- Department of Human Genetics, McGill University, Montreal, Canada
| | | | - Paul R Goodyer
- Research Institute of the McGill University Health Center, 1001 Décarie Boulevard, EM1.2232, Montreal, QC, H4A 3J1, Canada. .,Department of Experimental Medicine, McGill University, Montreal, Canada. .,Department of Human Genetics, McGill University, Montreal, Canada. .,Department of Pediatrics, McGill University, Montreal, Canada.
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7
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Sharma J, Keeling KM, Rowe SM. Pharmacological approaches for targeting cystic fibrosis nonsense mutations. Eur J Med Chem 2020; 200:112436. [PMID: 32512483 DOI: 10.1016/j.ejmech.2020.112436] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 12/11/2022]
Abstract
Cystic fibrosis (CF) is a monogenic autosomal recessive disorder. The clinical manifestations of the disease are caused by ∼2,000 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. It is unlikely that any one approach will be efficient in correcting all defects. The recent approvals of ivacaftor, lumacaftor/ivacaftor and elexacaftor/tezacaftor/ivacaftor represent the genesis of a new era of precision combination medicine for the CF patient population. In this review, we discuss targeted translational readthrough approaches as mono and combination therapies for CFTR nonsense mutations. We examine the current status of efficacy of translational readthrough/nonsense suppression therapies and their limitations, including non-native amino acid incorporation at PTCs and nonsense-mediated mRNA decay (NMD), along with approaches to tackle these limitations. We further elaborate on combining various therapies such as readthrough agents, NMD inhibitors, and corrector/potentiators to improve the efficacy and safety of suppression therapy. These mutation specific strategies that are directed towards the basic CF defects should positively impact CF patients bearing nonsense mutations.
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Affiliation(s)
- Jyoti Sharma
- Department of Medicine, University of Alabama at Birmingham (UAB), USA; Department of Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), USA
| | - Kim M Keeling
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), USA; Department of Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), USA
| | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham (UAB), USA; Department of Pediatrics, University of Alabama at Birmingham (UAB), USA; Department of Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham (UAB), USA.
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8
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Brasell EJ, Chu L, El Kares R, Seo JH, Loesch R, Iglesias DM, Goodyer P. The aminoglycoside geneticin permits translational readthrough of the CTNS W138X nonsense mutation in fibroblasts from patients with nephropathic cystinosis. Pediatr Nephrol 2019; 34:873-881. [PMID: 30413946 DOI: 10.1007/s00467-018-4094-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/13/2018] [Accepted: 09/19/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND Cystinosis is an ultrarare disorder caused by mutations of the cystinosin (CTNS) gene, encoding a cystine-selective efflux channel in the lysosomes of all cells of the body. Oral therapy with cysteamine reduces intralysosomal cystine accumulation and slows organ deterioration but cannot reverse renal Fanconi syndrome nor prevent the eventual need for renal transplantation. A definitive therapeutic remains elusive. About 15% of cystinosis patients worldwide carry one or more nonsense mutations that halt translation of the CTNS protein. Aminoglycosides such as geneticin (G418) can bind to the mammalian ribosome, relax translational fidelity, and permit readthrough of premature termination codons to produce full-length protein. METHODS To ascertain whether aminoglycosides permit readthrough of the most common CTNS nonsense mutation, W138X, we studied the effect of G418 on patient fibroblasts. RESULTS G418 treatment induced translational readthrough of CTNSW138X constructs transfected into HEK293 cells and expression of full-length endogenous CTNS protein in homozygous W138X fibroblasts. CONCLUSIONS Reduction in intracellular cystine indicates that the CTNS protein produced is functional as a cystine transporter. Interestingly, similar effects were seen even in W138X compound heterozygotes. These studies establish proof-of-principle for the potential of aminoglycosides to treat cystinosis and possibly other monogenic diseases caused by nonsense mutations.
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Affiliation(s)
- Emma J Brasell
- Department of Human Genetics, McGill University, Montreal, Québec, Canada
| | - LeeLee Chu
- The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada
| | - Reyhan El Kares
- The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada
| | - Jung Hwa Seo
- The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada
| | | | | | - Paul Goodyer
- Department of Human Genetics, McGill University, Montreal, Québec, Canada. .,The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada. .,Department of Experimental Medicine, McGill University, Montreal, Canada.
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9
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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: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Abstract
Fungal peroxisomes are characterized by a number of specific biological functions. To understand the physiology and biochemistry of these organelles knowledge of the proteome content is crucial. Here, we address different strategies to predict peroxisomal proteins by bioinformatics approaches. These tools range from simple text searches to network based learning strategies. A complication of this analysis is the existence of cryptic peroxisomal proteins, which are overlooked in conventional bioinformatics queries. These include proteins where targeting information results from transcriptional and posttranscriptional alterations. But also proteins with low efficiency targeting motifs that are predominantly localized in the cytosol, and proteins lacking any canonical targeting information, can play important roles within peroxisomes. Many of these proteins are so far unpredictable. Detection and characterization of these cryptic peroxisomal proteins revealed the presence of novel peroxisomal enzymatic reaction networks in fungi.
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Affiliation(s)
- Johannes Freitag
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Thorsten Stehlik
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Alina C Stiebler
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Michael Bölker
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany.
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11
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Yamaguchi Y, Baba H. Phylogenetically Conserved Sequences Around Myelin P0 Stop Codon are Essential for Translational Readthrough to Produce L-MPZ. Neurochem Res 2018; 43:227-37. [PMID: 29081003 DOI: 10.1007/s11064-017-2423-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/14/2017] [Accepted: 10/19/2017] [Indexed: 02/02/2023]
Abstract
Myelin protein zero (P0, MPZ) is the main cell adhesion molecule in peripheral myelin, the sequence of which is evolutionarily highly conserved. Large myelin protein zero (L-MPZ) is a novel translational readthrough molecule in mammals in a physiological status and is encoded by the P0 mRNA with an extra domain. The sequence similarities in the L-MPZ-specific region are found in humans and frogs but not in fish P0 cDNA. Actual synthesis of L-MPZ has been detected in rat and mouse sciatic nerve but not yet evaluated in frogs and humans. The production mechanism and physiological functions of L-MPZ remain unknown. Additionally, the sequence context around the canonical stop codon is significant for readthrough in viruses and yeast, but the correlation between the sequence around P0 stop codon and L-MPZ synthesis is unclear. Here, we focused on the phylogenetic pathways in L-MPZ synthesis. We have shown that L-MPZ is widely produced from frogs to humans using western blotting against L-MPZ. Mutation analysis of the sequence around the stop codon for L-MPZ synthesis using a mammalian in vitro transcription/translation system revealed that the evolutionarily conserved sequence around P0 stop codon is susceptible to readthrough and is similar to the consensus motif in viruses and yeast UAG stop codon type molecules. Our results demonstrate that the phylogenetically conserved sequence around the canonical P0 stop codon is essential for L-MPZ synthesis, suggesting that phylogenetic emergence of L-MPZ in amphibians may be related to particular distribution and/or function in the PNS myelin.
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12
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Abstract
Translational readthrough, the decoding of stop codons as sense codons, leads to C-terminal extension of proteins which may lead to the formation of protein isoforms with distinct properties from the original protein. Two proteins have recently been identified that are targeted to the peroxisome via hidden peroxisomal targeting signals in their readthrough extensions. This noninduced basal translational readthrough can be distinguished from pharmacological induction of readthrough by aminoglycosides or other small molecules, which can be used for the treatment of diseases caused by premature stop (termination) codons (PTCs). Readthrough of both, natural stop codons and PTCs, can be quantified in cell culture using reporter systems. In the present article, we describe two dual reporter systems, based on combined fluorescence/luminescence measurement and flow cytometric fluorescence measurement, respectively. Further, we provide a protocol for a fast and efficient cloning procedure of reporter constructs. The dual reporter systems described here help to analyze the peroxisome-specific isoforms of readthrough enzymes as well as potential readthrough therapeutics.
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Affiliation(s)
- Julia Hofhuis
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Severin Dieterle
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Rosemol George
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Fabian Schueren
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Health, University Medical Center G&ttingen, University of G&ttingen, Robert-Koch-Strasse 40, D-37075, G&ttingen, Germany. &ttingen.de
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