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Salman A, Biziaev N, Shuvalova E, Alkalaeva E. mRNA context and translation factors determine decoding in alternative nuclear genetic codes. Bioessays 2024; 46:e2400058. [PMID: 38724251 DOI: 10.1002/bies.202400058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 06/27/2024]
Abstract
The genetic code is a set of instructions that determine how the information in our genetic material is translated into amino acids. In general, it is universal for all organisms, from viruses and bacteria to humans. However, in the last few decades, exceptions to this rule have been identified both in pro- and eukaryotes. In this review, we discuss the 16 described alternative eukaryotic nuclear genetic codes and observe theories of their appearance in evolution. We consider possible molecular mechanisms that allow codon reassignment. Most reassignments in nuclear genetic codes are observed for stop codons. Moreover, in several organisms, stop codons can simultaneously encode amino acids and serve as termination signals. In this case, the meaning of the codon is determined by the additional factors besides the triplets. A comprehensive review of various non-standard coding events in the nuclear genomes provides a new insight into the translation mechanism in eukaryotes.
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Affiliation(s)
- Ali Salman
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Nikita Biziaev
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina Shuvalova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
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2
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Xie J, Zhang Z. Recent Advances and Therapeutic Implications of 2-Oxoglutarate-Dependent Dioxygenases in Ischemic Stroke. Mol Neurobiol 2024; 61:3949-3975. [PMID: 38041714 DOI: 10.1007/s12035-023-03790-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/08/2023] [Indexed: 12/03/2023]
Abstract
Ischemic stroke is a common disease with a high disability rate and mortality, which brings heavy pressure on families and medical insurance. Nowadays, the golden treatments for ischemic stroke in the acute phase mainly include endovascular therapy and intravenous thrombolysis. Some drugs are used to alleviate brain injury in patients with ischemic stroke, such as edaravone and 3-n-butylphthalide. However, no effective neuroprotective drug for ischemic stroke has been acknowledged. 2-Oxoglutarate-dependent dioxygenases (2OGDDs) are conserved and common dioxygenases whose activities depend on O2, Fe2+, and 2OG. Most 2OGDDs are expressed in the brain and are essential for the development and functions of the brain. Therefore, 2OGDDs likely play essential roles in ischemic brain injury. In this review, we briefly elucidate the functions of most 2OGDDs, particularly the effects of regulations of 2OGDDs on various cells in different phases after ischemic stroke. It would also provide promising potential therapeutic targets and directions of drug development for protecting the brain against ischemic injury and improving outcomes of ischemic stroke.
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Affiliation(s)
- Jian Xie
- Department of Neurology, Affiliated Zhongda Hospital, Research Institution of Neuropsychiatry, School of Medicine, Southeast University, Nanjing, 210009, Jiangsu, China
| | - Zhijun Zhang
- Department of Neurology, Affiliated Zhongda Hospital, Research Institution of Neuropsychiatry, School of Medicine, Southeast University, Nanjing, 210009, Jiangsu, China.
- Shenzhen Key Laboratory of Precision Diagnosis and Treatment of Depression, Department of Mental Health and Public Health, Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, Guangdong, China.
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3
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Querl L, Krebber H. The DEAD-box RNA helicase Dbp5 is a key protein that couples multiple steps in gene expression. Biol Chem 2023; 404:845-850. [PMID: 37436777 DOI: 10.1515/hsz-2023-0130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/03/2023] [Indexed: 07/13/2023]
Abstract
Cell viability largely depends on the surveillance of mRNA export and translation. Upon pre-mRNA processing and nuclear quality control, mature mRNAs are exported into the cytoplasm via Mex67-Mtr2 attachment. At the cytoplasmic site of the nuclear pore complex, the export receptor is displaced by the action of the DEAD-box RNA helicase Dbp5. Subsequent quality control of the open reading frame requires translation. Our studies suggest an involvement of Dbp5 in cytoplasmic no-go-and non-stop decay. Most importantly, we have also identified a key function for Dbp5 in translation termination, which identifies this helicase as a master regulator of mRNA expression.
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Affiliation(s)
- Luisa Querl
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
| | - Heike Krebber
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
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4
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Beryozkin A, Nagel-Wolfum K, Banin E, Sharon D. Factors Affecting Readthrough of Natural Versus Premature Termination Codons. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 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] [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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5
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Kachale A, Pavlíková Z, Nenarokova A, Roithová A, Durante IM, Miletínová P, Záhonová K, Nenarokov S, Votýpka J, Horáková E, Ross RL, Yurchenko V, Beznosková P, Paris Z, Valášek LS, Lukeš J. Short tRNA anticodon stem and mutant eRF1 allow stop codon reassignment. Nature 2023; 613:751-758. [PMID: 36631608 DOI: 10.1038/s41586-022-05584-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 11/18/2022] [Indexed: 01/13/2023]
Abstract
Cognate tRNAs deliver specific amino acids to translating ribosomes according to the standard genetic code, and three codons with no cognate tRNAs serve as stop codons. Some protists have reassigned all stop codons as sense codons, neglecting this fundamental principle1-4. Here we analyse the in-frame stop codons in 7,259 predicted protein-coding genes of a previously undescribed trypanosomatid, Blastocrithidia nonstop. We reveal that in this species in-frame stop codons are underrepresented in genes expressed at high levels and that UAA serves as the only termination codon. Whereas new tRNAsGlu fully cognate to UAG and UAA evolved to reassign these stop codons, the UGA reassignment followed a different path through shortening the anticodon stem of tRNATrpCCA from five to four base pairs (bp). The canonical 5-bp tRNATrp recognizes UGG as dictated by the genetic code, whereas its shortened 4-bp variant incorporates tryptophan also into in-frame UGA. Mimicking this evolutionary twist by engineering both variants from B. nonstop, Trypanosoma brucei and Saccharomyces cerevisiae and expressing them in the last two species, we recorded a significantly higher readthrough for all 4-bp variants. Furthermore, a gene encoding B. nonstop release factor 1 acquired a mutation that specifically restricts UGA recognition, robustly potentiating the UGA reassignment. Virtually the same strategy has been adopted by the ciliate Condylostoma magnum. Hence, we describe a previously unknown, universal mechanism that has been exploited in unrelated eukaryotes with reassigned stop codons.
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Affiliation(s)
- Ambar Kachale
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic
| | - Zuzana Pavlíková
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Anna Nenarokova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.,School of Biological Sciences, University of Bristol, Bristol, UK
| | - Adriana Roithová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Ignacio M Durante
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Petra Miletínová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic.,Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Serafim Nenarokov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic
| | - Jan Votýpka
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Eva Horáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Institute of Microbiology, Czech Academy of Sciences, Třeboň, Czech Republic
| | | | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Petra Beznosková
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
| | | | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
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6
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Shi N, Tong L, Lin H, Zheng Z, Zhang H, Dong L, Yang Y, Shen Y, Xia Q. Optimizing eRF1 to Enable the Genetic Encoding of Three Distinct Noncanonical Amino Acids in Mammalian Cells. Adv Biol (Weinh) 2022; 6:e2200092. [PMID: 35818694 DOI: 10.1002/adbi.202200092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/06/2022] [Indexed: 01/28/2023]
Abstract
Site-specific incorporation of distinct noncanonical amino acids (ncAAs) into proteins via genetic code expansion in mammalian cells represents a new avenue for protein engineering. Reassigning three TAGs with the same ncAA in mammalian cells has previously been achieved using translational machinery. However, simultaneous recoding of three nonsense codons with distinct ncAAs in mammalian cells remains a challenge due to low incorporation efficiencies. Here, three optimized aaRS/tRNA pairs (i.e., the E. coli-derived tyrosyl (EcTyr)/tRNAUUA , E. coli-derived leucyl (EcLeu)/tRNACUA , and Methanosarcina mazei pyrrolysyl (MmPyl)/tRNAUCA pairs) are screened for ncAA incorporation. Furthermore, introduced combinations of eukaryotic release factor 1 (eRF1) mutants (E55R, E55D, N129D, and Y125F) significantly improve the encoding efficiency of the three premature stop codons' sites from 0.78% to 11.6%. Thus, site-specific incorporation of three distinct ncAAs into a single protein is achieved in this study. This work markedly expands the potential for multiple site-specific protein modifications within mammalian cells, thereby facilitating new in vivo applications.
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Affiliation(s)
- Ningning Shi
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Le Tong
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Haishuang Lin
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Zhetao Zheng
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Haoran Zhang
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Liangzhen Dong
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Yuelin Yang
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Yuxuan Shen
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Qing Xia
- State Key Laboratory of Natural and Biomimetic Drugs Department of Chemical Biology School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
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Valadon C, Namy O. The Importance of the Epi-Transcriptome in Translation Fidelity. Noncoding RNA 2021; 7:51. [PMID: 34564313 PMCID: PMC8482273 DOI: 10.3390/ncrna7030051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/17/2021] [Accepted: 08/22/2021] [Indexed: 12/11/2022] Open
Abstract
RNA modifications play an essential role in determining RNA fate. Recent studies have revealed the effects of such modifications on all steps of RNA metabolism. These modifications range from the addition of simple groups, such as methyl groups, to the addition of highly complex structures, such as sugars. Their consequences for translation fidelity are not always well documented. Unlike the well-known m6A modification, they are thought to have direct effects on either the folding of the molecule or the ability of tRNAs to bind their codons. Here we describe how modifications found in tRNAs anticodon-loop, rRNA, and mRNA can affect translation fidelity, and how approaches based on direct manipulations of the level of RNA modification could potentially be used to modulate translation for the treatment of human genetic diseases.
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Affiliation(s)
| | - Olivier Namy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France;
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8
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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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Abramov D, Guiberson NGL, Burré J. STXBP1 encephalopathies: Clinical spectrum, disease mechanisms, and therapeutic strategies. J Neurochem 2021; 157:165-178. [PMID: 32643187 PMCID: PMC7812771 DOI: 10.1111/jnc.15120] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/24/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022]
Abstract
Mutations in Munc18-1/STXBP1 (syntaxin-binding protein 1) are linked to various severe early epileptic encephalopathies and neurodevelopmental disorders. Heterozygous mutations in the STXBP1 gene include missense, nonsense, frameshift, and splice site mutations, as well as intragenic deletions and duplications and whole-gene deletions. No genotype-phenotype correlation has been identified so far, and patients are treated by anti-epileptic drugs because of the lack of a specific disease-modifying therapy. The molecular disease mechanisms underlying STXBP1-linked disorders are yet to be fully understood, but both haploinsufficiency and dominant-negative mechanisms have been proposed. This review focuses on the current understanding of the phenotypic spectrum of STXBP1-linked disorders, as well as discusses disease mechanisms in the context of the numerous pathways in which STXBP1 functions in the brain. We additionally evaluate the available animal models to study these disorders and highlight potential therapeutic approaches for treating these devastating diseases.
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Affiliation(s)
- Debra Abramov
- Appel Institute for Alzheimer's Disease Research, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Noah Guy Lewis Guiberson
- Appel Institute for Alzheimer's Disease Research, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Jacqueline Burré
- Appel Institute for Alzheimer's Disease Research, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
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Amzal R, Thébaut A, Lapalus M, Almes M, Grosse B, Mareux E, Collado-Hilly M, Davit-Spraul A, Bidou L, Namy O, Jacquemin E, Gonzales E. Pharmacological Premature Termination Codon Readthrough of ABCB11 in Bile Salt Export Pump Deficiency: An In Vitro Study. Hepatology 2021; 73:1449-1463. [PMID: 32702170 DOI: 10.1002/hep.31476] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 05/22/2020] [Accepted: 06/15/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a severe hepatocellular cholestasis due to biallelic mutations in ABCB11 encoding the canalicular bile salt export pump (BSEP). Nonsense mutations are responsible for the most severe phenotypes. The aim was to assess the ability of drugs to induce readthrough of six nonsense mutations (p.Y354X, p.R415X, p.R470X, p.R1057X, p.R1090X, and p.E1302X) identified in patients with PFIC2. APPROACH AND RESULTS The ability of G418, gentamicin, and PTC124 to induce readthrough was studied using a dual gene reporter system in NIH3T3 cells. The ability of gentamicin to induce readthrough and to lead to the expression of a full-length protein was studied in human embryonic kidney 293 (HEK293), HepG2, and Can 10 cells using immunodetection assays. The function of the gentamicin-induced full-length protein was studied by measuring the [3 H]-taurocholate transcellular transport in stable Madin-Darby canine kidney clones co-expressing Na+-taurocholate co-transporting polypeptide (Ntcp). Combinations of gentamicin and chaperone drugs (ursodeoxycholic acid, 4-phenylbutyrate [4-PB]) were investigated. In NIH3T3, aminoglycosides significantly increased the readthrough level of all mutations studied, while PTC124 only slightly increased the readthrough of p.E1302X. Gentamicin induced a readthrough of p.R415X, p.R470X, p.R1057X, and p.R1090X in HEK293 cells. The resulting full-length proteins localized within the cytoplasm, except for BsepR1090X , which was also detected at the plasma membrane of human embryonic kidney HEK293 and at the canalicular membrane of Can 10 and HepG2 cells. Additional treatment with 4-PB and ursodeoxycholic acid significantly increased the canalicular proportion of full-length BsepR1090X protein in Can 10 cells. In Madin-Darby canine kidney clones, gentamicin induced a 40% increase of the BsepR1090X [3 H]-taurocholate transport, which was further increased with additional 4-PB treatment. CONCLUSION This study constitutes a proof of concept for readthrough therapy in selected patients with PFIC2 with nonsense mutations.
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Affiliation(s)
- Rachida Amzal
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Alice Thébaut
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Martine Lapalus
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Marion Almes
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Brigitte Grosse
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Elodie Mareux
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Mauricette Collado-Hilly
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Anne Davit-Spraul
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Biochemistry Unit, Assistance Publique-Hôpitaux de Paris, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Laure Bidou
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif sur Yvette cedex, France
- Sorbonne Universités, Université Pierre et Marie Curie, UPMC, Paris, France
| | - Olivier Namy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif sur Yvette cedex, France
| | - Emmanuel Jacquemin
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Emmanuel Gonzales
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
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11
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Si W, Li Y, Ye S, Li Z, Liu Y, Kuang W, Chen D, Zhu M. Methyltransferase 3 Mediated miRNA m6A Methylation Promotes Stress Granule Formation in the Early Stage of Acute Ischemic Stroke. Front Mol Neurosci 2020; 13:103. [PMID: 32581712 PMCID: PMC7289951 DOI: 10.3389/fnmol.2020.00103] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/13/2020] [Indexed: 12/21/2022] Open
Abstract
The modification of methyltransferase-like (METTL) enzymes plays important roles in various cellular responses by regulating microRNA expression. However, how m6A modification is involved in stress granule (SG) formation in the early stage of acute ischemic stroke by affecting the biogenesis processing of microRNAs remains unclear. Here, we established a middle cerebral artery occlusion (MCAO) model in rats and an oxygen-glucose deprivation/reperfusion (OGD/R) model in primary cortical neurons and PC12 cells to explore the potential mechanism between m6A modification and SG formation. The in vivo results showed that the level of infarction and apoptosis increased while SG formation decreased significantly within the ischemic cortex with improved reperfusion time after 2 h of ischemia. Consistent with the in vivo data, an inverse association between the apoptosis level and SG formation was observed in PC12 cells during the reperfusion period after 6 h of OGD stimulation. Both in vivo and in vitro results showed that the expression of METTL3 protein, m6A and miR-335 was significantly decreased with the reperfusion period. Overexpression of the METTL3 and METTL3 gene-knockdown in PC12 cells were achieved via plasmid transfection and CRISPR-Cas9 technology, respectively. Overexpression or knockdown of METTL3 in oxygen-glucose deprivation of PC12 cells resulted in functional maturation of miR-335, SG formation and apoptosis levels. In addition, we found that miR-335 enhanced SG formation through degradation of the mRNA of the eukaryotic translation termination factor (Erf1). In conclusion, we found that METTL3-mediated m6A methylation increases the maturation of miR-335, which promotes SG formation and reduces the apoptosis level of injury neurons and cells, and provides a potential therapeutic strategy for AIS.
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Affiliation(s)
- Wenwen Si
- Shenzhen Bao'an Traditional Chinese Medicine Hospital (Group), Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Yi Li
- The First Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shanyu Ye
- Department of Anatomy, The Research Center of Basic Integrative Medicine, Guangzhou University of Chinese Medicine, Guangzhou Higher Education Mega Center, Guangzhou, China
| | - Zhen Li
- Department of Anatomy, The Research Center of Basic Integrative Medicine, Guangzhou University of Chinese Medicine, Guangzhou Higher Education Mega Center, Guangzhou, China
| | - Yangping Liu
- Department of Anatomy, The Research Center of Basic Integrative Medicine, Guangzhou University of Chinese Medicine, Guangzhou Higher Education Mega Center, Guangzhou, China
| | - Weihong Kuang
- The Second Clinical Medical College, Guangdong Medical University, Dongguan, China
| | - Dongfeng Chen
- Department of Anatomy, The Research Center of Basic Integrative Medicine, Guangzhou University of Chinese Medicine, Guangzhou Higher Education Mega Center, Guangzhou, China
| | - Meiling Zhu
- Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, China
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12
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Beißel C, Grosse S, Krebber H. Dbp5/DDX19 between Translational Readthrough and Nonsense Mediated Decay. Int J Mol Sci 2020; 21:ijms21031085. [PMID: 32041247 PMCID: PMC7037193 DOI: 10.3390/ijms21031085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 01/21/2023] Open
Abstract
The DEAD-box protein Dbp5 (human DDX19) remodels RNA-protein complexes. Dbp5 functions in ribonucleoprotein export and translation termination. Termination occurs, when the ribosome has reached a stop codon through the Dbp5 mediated delivery of the eukaryotic termination factor eRF1. eRF1 contacts eRF3 upon dissociation of Dbp5, resulting in polypeptide chain release and subsequent ribosomal subunit splitting. Mutations in DBP5 lead to stop codon readthrough, because the eRF1 and eRF3 interaction is not controlled and occurs prematurely. This identifies Dbp5/DDX19 as a possible potent drug target for nonsense suppression therapy. Neurodegenerative diseases and cancer are caused in many cases by the loss of a gene product, because its mRNA contained a premature termination codon (PTC) and is thus eliminated through the nonsense mediated decay (NMD) pathway, which is described in the second half of this review. We discuss translation termination and NMD in the light of Dbp5/DDX19 and subsequently speculate on reducing Dbp5/DDX19 activity to allow readthrough of the PTC and production of a full-length protein to detract the RNA from NMD as a possible treatment for diseases.
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13
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Wangen JR, Green R. Stop codon context influences genome-wide stimulation of termination codon readthrough by aminoglycosides. eLife 2020; 9:52611. [PMID: 31971508 PMCID: PMC7089771 DOI: 10.7554/elife.52611] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/22/2020] [Indexed: 12/14/2022] Open
Abstract
Stop codon readthrough (SCR) occurs when the ribosome miscodes at a stop codon. Such readthrough events can be therapeutically desirable when a premature termination codon (PTC) is found in a critical gene. To study SCR in vivo in a genome-wide manner, we treated mammalian cells with aminoglycosides and performed ribosome profiling. We find that in addition to stimulating readthrough of PTCs, aminoglycosides stimulate readthrough of normal termination codons (NTCs) genome-wide. Stop codon identity, the nucleotide following the stop codon, and the surrounding mRNA sequence context all influence the likelihood of SCR. In comparison to NTCs, downstream stop codons in 3′UTRs are recognized less efficiently by ribosomes, suggesting that targeting of critical stop codons for readthrough may be achievable without general disruption of translation termination. Finally, we find that G418-induced miscoding alters gene expression with substantial effects on translation of histone genes, selenoprotein genes, and S-adenosylmethionine decarboxylase (AMD1). Many genes provide a set of instructions needed to build a protein, which are read by structures called ribosomes through a process called translation. The genetic information contains a short, coded instruction called a stop codon which marks the end of the protein. When a ribosome finds a stop codon it should stop building and release the protein it has made. Ribosomes do not always stop at stop codons. Certain chemicals can actually prevent ribosomes from detecting stop codons correctly, and aminoglycosides are drugs that have exactly this effect. Aminoglycosides can be used as antibiotics at low doses because they interfere with ribosomes in bacteria, but at higher doses they can also prevent ribosomes from detecting stop codons in human cells. When ribosomes do not stop at a stop codon this is called readthrough. There are different types of stop codons and some are naturally more effective at stopping ribosomes than others. Wangen and Green have now examined the effect of an aminoglycoside called G418 on ribosomes in human cells grown in the laboratory. The results showed how ribosomes interacted with genetic information and revealed that certain stop codons are more affected by G418 than others. The stop codon and other genetic sequences around it affect the likelihood of readthrough. Wangen and Green also showed that sequences that encourage translation to stop are more common in the area around stop codons. These findings highlight an evolutionary pressure driving more genes to develop strong stop codons that resist readthrough. Despite this, some are still more affected by drugs like G418 than others. Some genetic conditions, like cystic fibrosis, result from incorrect stop codons in genes. Drugs that promote readthrough specifically in these genes could be useful new treatments.
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Affiliation(s)
- Jamie R Wangen
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Rachel Green
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
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14
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Mutant GNLY is linked to Stevens-Johnson syndrome and toxic epidermal necrolysis. Hum Genet 2019; 138:1267-1274. [PMID: 31642954 DOI: 10.1007/s00439-019-02066-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/25/2019] [Indexed: 12/19/2022]
Abstract
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare severe cutaneous adverse reactions to drugs. Granulysin (GNLY) plays a key role in keratinocyte apoptosis during SJS/TEN pathophysiology. To determine if GNLY-encoding mutations might be related to the protein's functional disturbances, contributing to SJS/TEN pathogenesis, we performed direct sequencing of GNLY's coding region in a group of 19 Colombian SJS/TEN patients. A GNLY genetic screening was implemented in a group of 249 healthy individuals. We identified the c.11G > A heterozygous sequence variant in a TEN case, which creates a premature termination codon (PTC) (p.Trp4Ter). We show that a mutant protein is synthesised, possibly due to a PTC-readthrough mechanism. Functional assays demonstrated that the mutant protein was abnormally located in the nuclear compartment, potentially leading to a toxic effect. Our results argue in favour of GNLY non-synonymous sequence variants contributing to SJS/TEN pathophysiology, thereby constituting a promising, clinically useful molecular biomarker.
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15
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Hellen CUT. Translation Termination and Ribosome Recycling in Eukaryotes. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a032656. [PMID: 29735640 DOI: 10.1101/cshperspect.a032656] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Termination of mRNA translation occurs when a stop codon enters the A site of the ribosome, and in eukaryotes is mediated by release factors eRF1 and eRF3, which form a ternary eRF1/eRF3-guanosine triphosphate (GTP) complex. eRF1 recognizes the stop codon, and after hydrolysis of GTP by eRF3, mediates release of the nascent peptide. The post-termination complex is then disassembled, enabling its constituents to participate in further rounds of translation. Ribosome recycling involves splitting of the 80S ribosome by the ATP-binding cassette protein ABCE1 to release the 60S subunit. Subsequent dissociation of deacylated transfer RNA (tRNA) and messenger RNA (mRNA) from the 40S subunit may be mediated by initiation factors (priming the 40S subunit for initiation), by ligatin (eIF2D) or by density-regulated protein (DENR) and multiple copies in T-cell lymphoma-1 (MCT1). These events may be subverted by suppression of termination (yielding carboxy-terminally extended read-through polypeptides) or by interruption of recycling, leading to reinitiation of translation near the stop codon.
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Affiliation(s)
- Christopher U T Hellen
- Department of Cell Biology, State University of New York, Downstate Medical Center, New York, New York 11203
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16
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Hoernes TP, Clementi N, Juen MA, Shi X, Faserl K, Willi J, Gasser C, Kreutz C, Joseph S, Lindner H, Hüttenhofer A, Erlacher MD. Atomic mutagenesis of stop codon nucleotides reveals the chemical prerequisites for release factor-mediated peptide release. Proc Natl Acad Sci U S A 2018; 115:E382-E389. [PMID: 29298914 PMCID: PMC5776981 DOI: 10.1073/pnas.1714554115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Termination of protein synthesis is triggered by the recognition of a stop codon at the ribosomal A site and is mediated by class I release factors (RFs). Whereas in bacteria, RF1 and RF2 promote termination at UAA/UAG and UAA/UGA stop codons, respectively, eukaryotes only depend on one RF (eRF1) to initiate peptide release at all three stop codons. Based on several structural as well as biochemical studies, interactions between mRNA, tRNA, and rRNA have been proposed to be required for stop codon recognition. In this study, the influence of these interactions was investigated by using chemically modified stop codons. Single functional groups within stop codon nucleotides were substituted to weaken or completely eliminate specific interactions between the respective mRNA and RFs. Our findings provide detailed insight into the recognition mode of bacterial and eukaryotic RFs, thereby revealing the chemical groups of nucleotides that define the identity of stop codons and provide the means to discriminate against noncognate stop codons or UGG sense codons.
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Affiliation(s)
- Thomas Philipp Hoernes
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Nina Clementi
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Michael Andreas Juen
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Xinying Shi
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314
| | - Klaus Faserl
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Jessica Willi
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Catherina Gasser
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Simpson Joseph
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Alexander Hüttenhofer
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Matthias David Erlacher
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
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17
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Mikhailova T, Shuvalova E, Ivanov A, Susorov D, Shuvalov A, Kolosov PM, Alkalaeva E. RNA helicase DDX19 stabilizes ribosomal elongation and termination complexes. Nucleic Acids Res 2017; 45:1307-1318. [PMID: 28180304 PMCID: PMC5605241 DOI: 10.1093/nar/gkw1239] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 11/24/2016] [Accepted: 11/29/2016] [Indexed: 12/31/2022] Open
Abstract
The human DEAD-box RNA-helicase DDX19 functions in mRNA export through the nuclear pore complex. The yeast homolog of this protein, Dbp5, has been reported to participate in translation termination. Using a reconstituted mammalian in vitro translation system, we show that the human protein DDX19 is also important for translation termination. It is associated with the fraction of translating ribosomes. We show that DDX19 interacts with pre-termination complexes (preTCs) in a nucleotide-dependent manner. Furthermore, DDX19 increases the efficiency of termination complex (TC) formation and the peptide release in the presence of eukaryotic release factors. Using the eRF1(AGQ) mutant protein or a non-hydrolysable analog of GTP to inhibit subsequent peptidyl-tRNA hydrolysis, we reveal that the activation of translation termination by DDX19 occurs during the stop codon recognition. This activation is a result of DDX19 binding to preTC and a concomitant stabilization of terminating ribosomes. Moreover, we show that DDX19 stabilizes ribosome complexes with translation elongation factors eEF1 and eEF2. Taken together, our findings reveal that the human RNA helicase DDX19 actively participates in protein biosynthesis.
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Affiliation(s)
- Tatiana Mikhailova
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina Shuvalova
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow, Russia
| | - Alexander Ivanov
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Denis Susorov
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Alexey Shuvalov
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow, Russia
| | - Peter M Kolosov
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow, Russia.,Institute of Higher Nervous Activity and Neurophysiology, The Russian Academy of Sciences, Moscow, Russia
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow, Russia
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18
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Zhang Z, Xu H, Si L, Chen Y, Zhang B, Wang Y, Wu Y, Zhou X, Zhang L, Zhou D. Construction of an inducible stable cell line for efficient incorporation of unnatural amino acids in mammalian cells. Biochem Biophys Res Commun 2017; 489:490-496. [DOI: 10.1016/j.bbrc.2017.05.178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
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19
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Mechanism and Regulation of Protein Synthesis in Saccharomyces cerevisiae. Genetics 2017; 203:65-107. [PMID: 27183566 DOI: 10.1534/genetics.115.186221] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/24/2016] [Indexed: 12/18/2022] Open
Abstract
In this review, we provide an overview of protein synthesis in the yeast Saccharomyces cerevisiae The mechanism of protein synthesis is well conserved between yeast and other eukaryotes, and molecular genetic studies in budding yeast have provided critical insights into the fundamental process of translation as well as its regulation. The review focuses on the initiation and elongation phases of protein synthesis with descriptions of the roles of translation initiation and elongation factors that assist the ribosome in binding the messenger RNA (mRNA), selecting the start codon, and synthesizing the polypeptide. We also examine mechanisms of translational control highlighting the mRNA cap-binding proteins and the regulation of GCN4 and CPA1 mRNAs.
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20
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Pánek T, Žihala D, Sokol M, Derelle R, Klimeš V, Hradilová M, Zadrobílková E, Susko E, Roger AJ, Čepička I, Eliáš M. Nuclear genetic codes with a different meaning of the UAG and the UAA codon. BMC Biol 2017; 15:8. [PMID: 28193262 PMCID: PMC5304391 DOI: 10.1186/s12915-017-0353-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/23/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Departures from the standard genetic code in eukaryotic nuclear genomes are known for only a handful of lineages and only a few genetic code variants seem to exist outside the ciliates, the most creative group in this regard. Most frequent code modifications entail reassignment of the UAG and UAA codons, with evidence for at least 13 independent cases of a coordinated change in the meaning of both codons. However, no change affecting each of the two codons separately has been documented, suggesting the existence of underlying evolutionary or mechanistic constraints. RESULTS Here, we present the discovery of two new variants of the nuclear genetic code, in which UAG is translated as an amino acid while UAA is kept as a termination codon (along with UGA). The first variant occurs in an organism noticed in a (meta)transcriptome from the heteropteran Lygus hesperus and demonstrated to be a novel insect-dwelling member of Rhizaria (specifically Sainouroidea). This first documented case of a rhizarian with a non-canonical genetic code employs UAG to encode leucine and represents an unprecedented change among nuclear codon reassignments. The second code variant was found in the recently described anaerobic flagellate Iotanema spirale (Metamonada: Fornicata). Analyses of transcriptomic data revealed that I. spirale uses UAG to encode glutamine, similarly to the most common variant of a non-canonical code known from several unrelated eukaryotic groups, including hexamitin diplomonads (also a lineage of fornicates). However, in these organisms, UAA also encodes glutamine, whereas it is the primary termination codon in I. spirale. Along with phylogenetic evidence for distant relationship of I. spirale and hexamitins, this indicates two independent genetic code changes in fornicates. CONCLUSIONS Our study documents, for the first time, that evolutionary changes of the meaning of UAG and UAA codons in nuclear genomes can be decoupled and that the interpretation of the two codons by the cytoplasmic translation apparatus is mechanistically separable. The latter conclusion has interesting implications for possibilities of genetic code engineering in eukaryotes. We also present a newly developed generally applicable phylogeny-informed method for inferring the meaning of reassigned codons.
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Affiliation(s)
- Tomáš Pánek
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
| | - David Žihala
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
| | - Martin Sokol
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
| | - Romain Derelle
- Unité d'Ecologie, Systématique et Evolution, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud/Paris-Saclay, AgroParisTech, Orsay, France
| | - Vladimír Klimeš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic
| | - Miluše Hradilová
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague, Czech Republic
| | - Eliška Zadrobílková
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 00, Prague, Czech Republic
| | - Edward Susko
- Department of Mathematics and Statistics, Dalhousie University, Halifax, NS, B3H 4R2, Canada
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada
| | - Andrew J Roger
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, B3H 4R2, Canada
- Canadian Institute for Advanced Research, Program in Integrated Microbial Biodiversity, Toronto, ON, Canada
| | - Ivan Čepička
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 00, Prague, Czech Republic
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic.
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21
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Alkalaeva E, Mikhailova T. Reassigning stop codons via translation termination: How a few eukaryotes broke the dogma. Bioessays 2016; 39. [PMID: 28009453 DOI: 10.1002/bies.201600213] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The genetic code determines how amino acids are encoded within mRNA. It is universal among the vast majority of organisms, although several exceptions are known. Variant genetic codes are found in ciliates, mitochondria, and numerous other organisms. All revealed genetic codes (standard and variant) have at least one codon encoding a translation stop signal. However, recently two new genetic codes with a reassignment of all three stop codons were revealed in studies examining the protozoa transcriptomes. Here, we discuss this finding and the recent studies of variant genetic codes in eukaryotes. We consider the possible molecular mechanisms allowing the use of certain codons as sense and stop signals simultaneously. The results obtained by studying these amazing organisms represent a new and exciting insight into the mechanism of stop codon decoding in eukaryotes. Also see the video abstract here.
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Affiliation(s)
- Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Tatiana Mikhailova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
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22
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Záhonová K, Kostygov AY, Ševčíková T, Yurchenko V, Eliáš M. An Unprecedented Non-canonical Nuclear Genetic Code with All Three Termination Codons Reassigned as Sense Codons. Curr Biol 2016; 26:2364-9. [PMID: 27593378 DOI: 10.1016/j.cub.2016.06.064] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 06/25/2016] [Accepted: 06/28/2016] [Indexed: 12/31/2022]
Abstract
A limited number of non-canonical genetic codes have been described in eukaryotic nuclear genomes. Most involve reassignment of one or two termination codons as sense ones [1-4], but no code variant is known that would have reassigned all three termination codons. Here, we describe such a variant that we discovered in a clade of trypanosomatids comprising nominal Blastocrithidia species. In these protists, UGA has been reassigned to encode tryptophan, while UAG and UAA (UAR) have become glutamate encoding. Strikingly, UAA and, less frequently, UAG also serve as bona fide termination codons. The release factor eRF1 in Blastocrithidia contains a substitution of a conserved serine residue predicted to decrease its affinity to UGA, which explains why this triplet can be read as a sense codon. However, the molecular basis for the dual interpretation of UAR codons remains elusive. Our findings expand the limits of comprehension of one of the fundamental processes in molecular biology.
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Affiliation(s)
- Kristína Záhonová
- Life Science Research Centre, Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic; Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Alexei Y Kostygov
- Life Science Research Centre, Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic; Zoological Institute of the Russian Academy of Sciences, Universitetskaya nab. 1, 199034 Saint Petersburg, Russia
| | - Tereza Ševčíková
- Life Science Research Centre, Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic; Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic; Institute of Parasitology, Czech Academy of Sciences, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Marek Eliáš
- Life Science Research Centre, Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic; Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.
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23
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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: 126] [Impact Index Per Article: 15.8] [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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24
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Trotta E. Selective forces and mutational biases drive stop codon usage in the human genome: a comparison with sense codon usage. BMC Genomics 2016; 17:366. [PMID: 27188984 PMCID: PMC4869280 DOI: 10.1186/s12864-016-2692-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/05/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The three stop codons UAA, UAG, and UGA signal the termination of mRNA translation. As a result of a mechanism that is not adequately understood, they are normally used with unequal frequencies. RESULTS In this work, we showed that selective forces and mutational biases drive stop codon usage in the human genome. We found that, in respect to sense codons, stop codon usage was affected by stronger selective forces but was less influenced by neutral mutational biases. UGA is the most frequent termination codon in human genome. However, UAA was the preferred stop codon in genes with high breadth of expression, high level of expression, AT-rich coding sequences, housekeeping functions, and in gene ontology categories with the largest deviation from expected stop codon usage. Selective forces associated with the breadth and the level of expression favoured AT-rich sequences in the mRNA region including the stop site and its proximal 3'-UTR, but acted with scarce effects on sense codons, generating two regions, upstream and downstream of the stop codon, with strongly different base composition. By favouring low levels of GC-content, selection promoted labile local secondary structures at the stop site and its proximal 3'-UTR. The compositional and structural context favoured by selection was surprisingly emphasized in the class of ribosomal proteins and was consistent with sequence elements that increase the efficiency of translational termination. Stop codons were also heterogeneously distributed among chromosomes by a mechanism that was strongly correlated with the GC-content of coding sequences. CONCLUSIONS In human genome, the nucleotide composition and the thermodynamic stability of stop codon site and its proximal 3'-UTR are correlated with the GC-content of coding sequences and with the breadth and the level of gene expression. In highly expressed genes stop codon usage is compositionally and structurally consistent with highly efficient translation termination signals.
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Affiliation(s)
- Edoardo Trotta
- Institute of Translational Pharmacology, Consiglio Nazionale delle Ricerche (CNR), Rome, 00133, Italy.
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Bezerra AR, Guimarães AR, Santos MAS. Non-Standard Genetic Codes Define New Concepts for Protein Engineering. Life (Basel) 2015; 5:1610-28. [PMID: 26569314 PMCID: PMC4695839 DOI: 10.3390/life5041610] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/12/2015] [Accepted: 10/21/2015] [Indexed: 11/16/2022] Open
Abstract
The essential feature of the genetic code is the strict one-to-one correspondence between codons and amino acids. The canonical code consists of three stop codons and 61 sense codons that encode 20% of the amino acid repertoire observed in nature. It was originally designated as immutable and universal due to its conservation in most organisms, but sequencing of genes from the human mitochondrial genomes revealed deviations in codon assignments. Since then, alternative codes have been reported in both nuclear and mitochondrial genomes and genetic code engineering has become an important research field. Here, we review the most recent concepts arising from the study of natural non-standard genetic codes with special emphasis on codon re-assignment strategies that are relevant to engineering genetic code in the laboratory. Recent tools for synthetic biology and current attempts to engineer new codes for incorporation of non-standard amino acids are also reviewed in this article.
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Affiliation(s)
- Ana R Bezerra
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
| | - Ana R Guimarães
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
| | - Manuel A S Santos
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
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Matheisl S, Berninghausen O, Becker T, Beckmann R. Structure of a human translation termination complex. Nucleic Acids Res 2015; 43:8615-26. [PMID: 26384426 PMCID: PMC4605324 DOI: 10.1093/nar/gkv909] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 08/12/2015] [Indexed: 12/02/2022] Open
Abstract
In contrast to bacteria that have two release factors, RF1 and RF2, eukaryotes only possess one unrelated release factor eRF1, which recognizes all three stop codons of the mRNA and hydrolyses the peptidyl-tRNA bond. While the molecular basis for bacterial termination has been elucidated, high-resolution structures of eukaryotic termination complexes have been lacking. Here we present a 3.8 Å structure of a human translation termination complex with eRF1 decoding a UAA(A) stop codon. The complex was formed using the human cytomegalovirus (hCMV) stalling peptide, which perturbs the peptidyltransferase center (PTC) to silence the hydrolysis activity of eRF1. Moreover, unlike sense codons or bacterial stop codons, the UAA stop codon adopts a U-turn-like conformation within a pocket formed by eRF1 and the ribosome. Inducing the U-turn conformation for stop codon recognition rationalizes how decoding by eRF1 includes monitoring geometry in order to discriminate against sense codons.
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Affiliation(s)
- Sarah Matheisl
- Gene Center and Center for integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Str. 25, University of Munich, 81377 Munich, Germany
| | - Otto Berninghausen
- Gene Center and Center for integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Str. 25, University of Munich, 81377 Munich, Germany
| | - Thomas Becker
- Gene Center and Center for integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Str. 25, University of Munich, 81377 Munich, Germany
| | - Roland Beckmann
- Gene Center and Center for integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Str. 25, University of Munich, 81377 Munich, Germany
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27
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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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