1
|
Evans MM, Liu S, Krautner JS, Seguin CG, Leung R, Ronald JA. Evaluation of DNA minicircles for delivery of adenine and cytosine base editors using activatable gene on "GO" reporter imaging systems. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102248. [PMID: 39040503 PMCID: PMC11260848 DOI: 10.1016/j.omtn.2024.102248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 06/07/2024] [Indexed: 07/24/2024]
Abstract
Over 30,000 point mutations are associated with debilitating diseases, including many cancer types, underscoring a critical need for targeted genomic solutions. CRISPR base editors, like adenine base editors (ABEs) and cytosine base editors (CBEs), enable precise modifications by converting adenine to guanine and cytosine to thymine, respectively. Challenges in efficiency and safety concerns regarding viral vectors used in delivery limit the scope of base editing. This study introduces non-viral minicircles, bacterial-backbone-free plasmids, as a delivery vehicle for ABEs and CBEs. The research uses cells engineered with the "Gene On" (GO) reporter gene systems for tracking minicircle-delivered ABEs, CBEs, or Cas9 nickase (control), using green fluorescent protein (GFPGO), bioluminescence reporter firefly luciferase (LUCGO), or a highly sensitive Akaluciferase (AkalucGO) designed in this study. The results show that transfection of minicircles expressing CBE or ABE resulted in significantly higher GFP expression and luminescence signals over controls, with minicircles demonstrating the most substantial editing. This study presents minicircles as a new strategy for base editor delivery and develops an enhanced bioluminescence imaging reporter system for tracking ABE activity. Future studies aim to evaluate the use of minicircles in preclinical cancer models, facilitating potential clinical applications.
Collapse
Affiliation(s)
- Melissa M. Evans
- Robarts Research Institute, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Shirley Liu
- Robarts Research Institute, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Joshua S. Krautner
- Robarts Research Institute, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Caroline G. Seguin
- Robarts Research Institute, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Rajan Leung
- Robarts Research Institute, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1, Canada
| | - John A. Ronald
- Robarts Research Institute, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1, Canada
- Lawson Health Research Institute, London, ON N6C 2R5, Canada
| |
Collapse
|
2
|
Toledano I, Supek F, Lehner B. Genome-scale quantification and prediction of pathogenic stop codon readthrough by small molecules. Nat Genet 2024; 56:1914-1924. [PMID: 39174735 PMCID: PMC11387191 DOI: 10.1038/s41588-024-01878-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 07/23/2024] [Indexed: 08/24/2024]
Abstract
Premature termination codons (PTCs) cause ~10-20% of inherited diseases and are a major mechanism of tumor suppressor gene inactivation in cancer. A general strategy to alleviate the effects of PTCs would be to promote translational readthrough. Nonsense suppression by small molecules has proven effective in diverse disease models, but translation into the clinic is hampered by ineffective readthrough of many PTCs. Here we directly tackle the challenge of defining drug efficacy by quantifying the readthrough of ~5,800 human pathogenic stop codons by eight drugs. We find that different drugs promote the readthrough of complementary subsets of PTCs defined by local sequence context. This allows us to build interpretable models that accurately predict drug-induced readthrough genome-wide, and we validate these models by quantifying endogenous stop codon readthrough. Accurate readthrough quantification and prediction will empower clinical trial design and the development of personalized nonsense suppression therapies.
Collapse
Affiliation(s)
- Ignasi Toledano
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Fran Supek
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
| | - Ben Lehner
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
- University Pompeu Fabra (UPF), Barcelona, Spain.
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.
| |
Collapse
|
3
|
Ward C, Beharry A, Tennakoon R, Rozik P, Wilhelm SDP, Heinemann IU, O’Donoghue P. Mechanisms and Delivery of tRNA Therapeutics. Chem Rev 2024; 124:7976-8008. [PMID: 38801719 PMCID: PMC11212642 DOI: 10.1021/acs.chemrev.4c00142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/11/2024] [Accepted: 04/26/2024] [Indexed: 05/29/2024]
Abstract
Transfer ribonucleic acid (tRNA) therapeutics will provide personalized and mutation specific medicines to treat human genetic diseases for which no cures currently exist. The tRNAs are a family of adaptor molecules that interpret the nucleic acid sequences in our genes into the amino acid sequences of proteins that dictate cell function. Humans encode more than 600 tRNA genes. Interestingly, even healthy individuals contain some mutant tRNAs that make mistakes. Missense suppressor tRNAs insert the wrong amino acid in proteins, and nonsense suppressor tRNAs read through premature stop signals to generate full length proteins. Mutations that underlie many human diseases, including neurodegenerative diseases, cancers, and diverse rare genetic disorders, result from missense or nonsense mutations. Thus, specific tRNA variants can be strategically deployed as therapeutic agents to correct genetic defects. We review the mechanisms of tRNA therapeutic activity, the nature of the therapeutic window for nonsense and missense suppression as well as wild-type tRNA supplementation. We discuss the challenges and promises of delivering tRNAs as synthetic RNAs or as gene therapies. Together, tRNA medicines will provide novel treatments for common and rare genetic diseases in humans.
Collapse
Affiliation(s)
- Cian Ward
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Aruun Beharry
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Rasangi Tennakoon
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Peter Rozik
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Sarah D. P. Wilhelm
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Ilka U. Heinemann
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Patrick O’Donoghue
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| |
Collapse
|
4
|
Moore PB. On the response of elongating ribosomes to forces opposing translocation. Biophys J 2024:S0006-3495(24)00381-3. [PMID: 38845199 DOI: 10.1016/j.bpj.2024.05.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/21/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
The elongation phase of protein synthesis is a cyclic, steady-state process. It follows that its directionality is determined by the thermodynamics of the accompanying chemical reactions, which strongly favor elongation. Its irreversibility is guaranteed by its coupling to those reactions, rather being a consequence of any of the conformational changes that occur as it unfolds. It also follows that, in general, the rate of elongation is not proportional to the forward rate constants of any of its steps, including its final, mechano-chemical step, translocation. Instead, the reciprocal of the rate of elongation should be linearly related to the reciprocal of those rate constants. When the results of experiments done a decade ago to measure the effect that forces opposing translocation have on the rate of elongation are reinterpreted in light of these findings, it becomes clear that translocation was rate limiting under conditions in which those experiments were done, and that it is likely to be a Brownian ratchet process, as was concluded earlier.
Collapse
Affiliation(s)
- Peter B Moore
- Department of Chemistry, Yale University, New Haven, Connecticut.
| |
Collapse
|
5
|
Tierney JAS, Świrski M, Tjeldnes H, Mudge JM, Kufel J, Whiffin N, Valen E, Baranov PV. Ribosome decision graphs for the representation of eukaryotic RNA translation complexity. Genome Res 2024; 34:530-538. [PMID: 38719470 PMCID: PMC11146595 DOI: 10.1101/gr.278810.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 04/01/2024] [Indexed: 05/21/2024]
Abstract
The application of ribosome profiling has revealed an unexpected abundance of translation in addition to that responsible for the synthesis of previously annotated protein-coding regions. Multiple short sequences have been found to be translated within single RNA molecules, within both annotated protein-coding and noncoding regions. The biological significance of this translation is a matter of intensive investigation. However, current schematic or annotation-based representations of mRNA translation generally do not account for the apparent multitude of translated regions within the same molecules. They also do not take into account the stochasticity of the process that allows alternative translations of the same RNA molecules by different ribosomes. There is a need for formal representations of mRNA complexity that would enable the analysis of quantitative information on translation and more accurate models for predicting the phenotypic effects of genetic variants affecting translation. To address this, we developed a conceptually novel abstraction that we term ribosome decision graphs (RDGs). RDGs represent translation as multiple ribosome paths through untranslated and translated mRNA segments. We termed the latter "translons." Nondeterministic events, such as initiation, reinitiation, selenocysteine insertion, or ribosomal frameshifting, are then represented as branching points. This representation allows for an adequate representation of eukaryotic translation complexity and focuses on locations critical for translation regulation. We show how RDGs can be used for depicting translated regions and for analyzing genetic variation and quantitative genome-wide data on translation for characterization of regulatory modulators of translation.
Collapse
Affiliation(s)
- Jack A S Tierney
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 K8AF, Ireland
- SFI Centre for Research Training in Genomics Data Science, University College Cork, Cork T12 K8AF, Ireland
| | - Michał Świrski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Håkon Tjeldnes
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 K8AF, Ireland
- Computational Biology Unit, Department of Informatics, University of Bergen, NO-5020 Bergen, Norway
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton CB10 1SD, Cambridge, United Kingdom
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Nicola Whiffin
- The Big Data Institute and Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Eivind Valen
- Computational Biology Unit, Department of Informatics, University of Bergen, NO-5020 Bergen, Norway
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 K8AF, Ireland;
| |
Collapse
|
6
|
Lukhovitskaya N, Brown K, Hua L, Pate AE, Carr JP, Firth AE. A novel ilarvirus protein CP-RT is expressed via stop codon readthrough and suppresses RDR6-dependent RNA silencing. PLoS Pathog 2024; 20:e1012034. [PMID: 38814986 PMCID: PMC11166343 DOI: 10.1371/journal.ppat.1012034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 06/11/2024] [Accepted: 05/03/2024] [Indexed: 06/01/2024] Open
Abstract
Ilarviruses are a relatively understudied but important group of plant RNA viruses that includes a number of crop pathogens. Their genomes comprise three RNA segments encoding two replicase subunits, movement protein, coat protein (CP), and (in some ilarvirus subgroups) a protein that suppresses RNA silencing. Here we report that, in many ilarviruses, RNA3 encodes an additional protein (termed CP-RT) as a result of ribosomal readthrough of the CP stop codon into a short downstream readthrough (RT) ORF. Using asparagus virus 2 as a model, we find that CP-RT is expressed in planta where it functions as a weak suppressor of RNA silencing. CP-RT expression is essential for persistent systemic infection in leaves and shoot apical meristem. CP-RT function is dependent on a putative zinc-finger motif within RT. Replacing the asparagus virus 2 RT with the RT of an ilarvirus from a different subgroup restored the ability to establish persistent infection. These findings open up a new avenue for research on ilarvirus silencing suppression, persistent meristem invasion and vertical transmission.
Collapse
Affiliation(s)
- Nina Lukhovitskaya
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Katherine Brown
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Lei Hua
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Adrienne E. Pate
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - John P. Carr
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Andrew E. Firth
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
7
|
Girardo B, Schopfer LM, Yue Y, Lockridge O, Larson MA. Polyaminated, acetylated and stop codon readthrough of recombinant Francisella tularensis universal stress protein in Escherichia coli. PLoS One 2024; 19:e0299701. [PMID: 38683788 PMCID: PMC11057771 DOI: 10.1371/journal.pone.0299701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/14/2024] [Indexed: 05/02/2024] Open
Abstract
Recombinant Francisella tularensis universal stress protein with a C-terminal histidine-tag (rUsp/His6) was expressed in Escherichia coli. Endogenous F. tularensis Usp has a predicted molecular mass of 30 kDa, but rUsp/His6 had an apparent molecular weight of 33 kDa based on Western blot analyses. To determine the source of the higher molecular weight for rUsp/His6, post translational modifications were examined. Tryptic peptides of purified rUsp/His6 were subjected to liquid chromatography tandem mass spectrometry (LC-MS/MS) and fragmentation spectra were searched for acetylated lysines and polyaminated glutamines. Of the 24 lysines in rUsp/His6, 10 were acetylated (K63, K68, K72, K129, K175, K201, K208, K212, K233, and K238) and three of the four glutamines had putrescine, spermidine and spermine adducts (Q55, Q60 and Q267). The level of post-translational modification was substoichiometric, eliminating the possibility that these modifications were the sole contributor to the 3 kDa extra mass of rUsp/His6. LC-MS/MS revealed that stop codon readthrough had occurred resulting in the unexpected addition of 20 extra amino acids at the C-terminus of rUsp/His6, after the histidine tag. Further, the finding of polyaminated glutamines in rUsp/His6 indicated that E. coli is capable of transglutaminase activity.
Collapse
Affiliation(s)
- Benjamin Girardo
- Pathology and Microbiology Department, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Lawrence M. Schopfer
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Yinshi Yue
- Pathology and Microbiology Department, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Marilynn A. Larson
- Pathology and Microbiology Department, University of Nebraska Medical Center, Omaha, NE, United States of America
| |
Collapse
|
8
|
Premchandar A, Ming R, Baiad A, Da Fonte DF, Xu H, Faubert D, Veit G, Lukacs GL. Readthrough-induced misincorporated amino acid ratios guide mutant-specific therapeutic approaches for two CFTR nonsense mutations. Front Pharmacol 2024; 15:1389586. [PMID: 38725656 PMCID: PMC11079177 DOI: 10.3389/fphar.2024.1389586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 03/28/2024] [Indexed: 05/12/2024] Open
Abstract
Cystic fibrosis (CF) is a monogenic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Premature termination codons (PTCs) represent ∼9% of CF mutations that typically cause severe expression defects of the CFTR anion channel. Despite the prevalence of PTCs as the underlying cause of genetic diseases, understanding the therapeutic susceptibilities of their molecular defects, both at the transcript and protein levels remains partially elucidated. Given that the molecular pathologies depend on the PTC positions in CF, multiple pharmacological interventions are required to suppress the accelerated nonsense-mediated mRNA decay (NMD), to correct the CFTR conformational defect caused by misincorporated amino acids, and to enhance the inefficient stop codon readthrough. The G418-induced readthrough outcome was previously investigated only in reporter models that mimic the impact of the local sequence context on PTC mutations in CFTR. To identify the misincorporated amino acids and their ratios for PTCs in the context of full-length CFTR readthrough, we developed an affinity purification (AP)-tandem mass spectrometry (AP-MS/MS) pipeline. We confirmed the incorporation of Cys, Arg, and Trp residues at the UGA stop codons of G542X, R1162X, and S1196X in CFTR. Notably, we observed that the Cys and Arg incorporation was favored over that of Trp into these CFTR PTCs, suggesting that the transcript sequence beyond the proximity of PTCs and/or other factors can impact the amino acid incorporation and full-length CFTR functional expression. Additionally, establishing the misincorporated amino acid ratios in the readthrough CFTR PTCs aided in maximizing the functional rescue efficiency of PTCs by optimizing CFTR modulator combinations. Collectively, our findings contribute to the understanding of molecular defects underlying various CFTR nonsense mutations and provide a foundation to refine mutation-dependent therapeutic strategies for various CF-causing nonsense mutations.
Collapse
Affiliation(s)
| | - Ruiji Ming
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Abed Baiad
- Department of Physiology, McGill University, Montréal, QC, Canada
| | | | - Haijin Xu
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Denis Faubert
- IRCM Mass Spectrometry and Proteomics Platform, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
| | - Guido Veit
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Gergely L. Lukacs
- Department of Physiology, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| |
Collapse
|
9
|
Kolakada D, Fu R, Biziaev N, Shuvalov A, Lore M, Campbell AE, Cortázar MA, Sajek MP, Hesselberth JR, Mukherjee N, Alkalaeva E, Jagannathan S. Systematic analysis of nonsense variants uncovers peptide release rate as a novel modifier of nonsense-mediated mRNA decay efficiency. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575080. [PMID: 38260612 PMCID: PMC10802582 DOI: 10.1101/2024.01.10.575080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Nonsense variants underlie many genetic diseases. The phenotypic impact of nonsense variants is determined by Nonsense-mediated mRNA decay (NMD), which degrades transcripts with premature termination codons (PTCs). NMD activity varies across transcripts and cellular contexts via poorly understood mechanisms. Here, by leveraging human genetic datasets, we uncover that the amino acid preceding the PTC dramatically affects NMD activity in human cells. We find that glycine codons in particular support high levels of NMD and are enriched before PTCs but depleted before normal termination codons (NTCs). Gly-PTC enrichment is most pronounced in human genes that tolerate loss-of-function variants. This suggests a strong biological impact for Gly-PTC in ensuring robust elimination of potentially toxic truncated proteins from non-essential genes. Biochemical assays revealed that the peptide release rate during translation termination is highly dependent on the identity of the amino acid preceding the stop codon. This release rate is the most critical feature determining NMD activity across our massively parallel reporter assays. Together, we conclude that NMD activity is significantly modulated by the "window of opportunity" offered by translation termination kinetics. Integrating the window of opportunity model with the existing framework of NMD would enable more accurate nonsense variant interpretation in the clinic.
Collapse
Affiliation(s)
- Divya Kolakada
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Molecular Biology Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Rui Fu
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Nikita Biziaev
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexey Shuvalov
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, 119991 Moscow, Russia
| | - Mlana Lore
- Molecular Biology Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Amy E. Campbell
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Michael A. Cortázar
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Marcin P. Sajek
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
| | - Jay R. Hesselberth
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Neelanjan Mukherjee
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, 119991 Moscow, Russia
| | - Sujatha Jagannathan
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Lead contact
| |
Collapse
|
10
|
Kolakada D, Campbell AE, Galvis LB, Li Z, Lore M, Jagannathan S. A system of reporters for comparative investigation of EJC-independent and EJC-enhanced nonsense-mediated mRNA decay. Nucleic Acids Res 2024; 52:e34. [PMID: 38375914 PMCID: PMC11014337 DOI: 10.1093/nar/gkae121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 01/05/2024] [Accepted: 02/07/2024] [Indexed: 02/21/2024] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a network of pathways that degrades transcripts that undergo premature translation termination. In mammals, NMD can be divided into the exon junction complex (EJC)-enhanced and EJC-independent branches. Fluorescence- and luminescence-based reporters have long been effective tools to investigate NMD, yet existing reporters largely focus on the EJC-enhanced pathway. Here, we present a system of reporters for comparative studies of EJC-independent and EJC-enhanced NMD. This system also enables the study of NMD-associated outcomes such as premature termination codon (PTC) readthrough and truncated protein degradation. These reporters are compatible with fluorescence or luminescence-based readouts via transient transfection or stable integration. Using this reporter system, we show that EJC-enhanced NMD RNA levels are reduced by 2- or 9-fold and protein levels are reduced by 7- or 12-fold compared to EJC-independent NMD, depending on the reporter gene used. Additionally, the extent of readthrough induced by G418 and an NMD inhibitor (SMG1i), alone and in combination, varies across NMD substrates. When combined, G418 and SMG1i increase readthrough product levels in an additive manner for EJC-independent reporters, while EJC-enhanced reporters show a synergistic effect. We present these reporters as a valuable toolkit to deepen our understanding of NMD and its associated mechanisms.
Collapse
Affiliation(s)
- Divya Kolakada
- Molecular Biology Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Amy E Campbell
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Laura Baquero Galvis
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Zhongyou Li
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mlana Lore
- Molecular Biology Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sujatha Jagannathan
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| |
Collapse
|
11
|
Witzenberger M, Schwartz S. Directing RNA-modifying machineries towards endogenous RNAs: opportunities and challenges. Trends Genet 2024; 40:313-325. [PMID: 38350740 DOI: 10.1016/j.tig.2024.01.001] [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: 11/16/2023] [Revised: 01/02/2024] [Accepted: 01/02/2024] [Indexed: 02/15/2024]
Abstract
Over 170 chemical modifications can be naturally installed on RNA, all of which are catalyzed by dedicated machineries. These modifications can alter RNA sequence structure, stability, and translation as well as serving as quality control marks that record aspects of RNA processing. The diverse roles played by RNAs within cells has motivated endeavors to exogenously introduce RNA modifications at target sites for diverse purposes ranging from recording RNA:protein interactions to therapeutic applications. Here, we discuss these applications and the approaches that have been employed to engineer RNA-modifying machineries, and highlight persisting challenges and perspectives.
Collapse
Affiliation(s)
- Monika Witzenberger
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7630031, Israel.
| | - Schraga Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7630031, Israel.
| |
Collapse
|
12
|
Mangkalaphiban K, Fu L, Du M, Thrasher K, Keeling KM, Bedwell DM, Jacobson A. Extended stop codon context predicts nonsense codon readthrough efficiency in human cells. Nat Commun 2024; 15:2486. [PMID: 38509072 PMCID: PMC10954755 DOI: 10.1038/s41467-024-46703-z] [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: 08/01/2023] [Accepted: 03/06/2024] [Indexed: 03/22/2024] Open
Abstract
Protein synthesis terminates when a stop codon enters the ribosome's A-site. Although termination is efficient, stop codon readthrough can occur when a near-cognate tRNA outcompetes release factors during decoding. Seeking to understand readthrough regulation we used a machine learning approach to analyze readthrough efficiency data from published HEK293T ribosome profiling experiments and compared it to comparable yeast experiments. We obtained evidence for the conservation of identities of the stop codon, its context, and 3'-UTR length (when termination is compromised), but not the P-site codon, suggesting a P-site tRNA role in readthrough regulation. Models trained on data from cells treated with the readthrough-promoting drug, G418, accurately predicted readthrough of premature termination codons arising from CFTR nonsense alleles that cause cystic fibrosis. This predictive ability has the potential to aid development of nonsense suppression therapies by predicting a patient's likelihood of improvement in response to drugs given their nonsense mutation sequence context.
Collapse
Affiliation(s)
- Kotchaphorn Mangkalaphiban
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, 368 Plantation Street, Worcester, MA, 01655, USA
- Department of Genomics and Computational Biology, UMass Chan Medical School, 368 Plantation Street, Worcester, MA, 01655, USA
| | - Lianwu Fu
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, The University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL, 35294, USA
| | - Ming Du
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, The University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL, 35294, USA
| | - Kari Thrasher
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, The University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL, 35294, USA
| | - Kim M Keeling
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, The University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL, 35294, USA
| | - David M Bedwell
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, The University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL, 35294, USA
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, 368 Plantation Street, Worcester, MA, 01655, USA.
| |
Collapse
|
13
|
Lee PJ, Soares AR, Sun Y, Fai C, Picciotto MR, Guo JU. Alternative translation initiation produces synaptic organizer proteoforms with distinct localization and functions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.16.580719. [PMID: 38405936 PMCID: PMC10888845 DOI: 10.1101/2024.02.16.580719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
While previous studies suggest that many mRNAs contain more than one translation initiation site (TIS), the biological significance of most alternative TISs and their corresponding protein isoforms (proteoforms) remains undetermined. Here we show that alternative translation initiation at a CUG and an AUG TIS in neuronal pentraxin receptor (NPR) mRNA produces two proteoforms, and their relative abundance is regulated by both neuronal activity as well as an adjacent RNA secondary structure. Downstream AUG initiation transforms the N-terminal transmembrane domain into a signal peptide, thereby converting NPR to a secreted factor sufficient to promote synaptic clustering of AMPA-type glutamate receptors. Changing the relative proteoform ratio, but not the overall NPR abundance reduces AMPA receptor in parvalbumin (PV)-positive interneurons and induces changes in learning behaviors in mice. In addition to NPR, N-terminal extensions of C1q-like synaptic organizers, mediated by upstream AUU start codons, anchor these otherwise secreted factors to the membrane. Thus, our results uncovered the plasticity of N-terminal signal sequences regulated by alternative TIS usage as a widespread mechanism to diversify protein localization and functions.
Collapse
Affiliation(s)
- Paul Jongseo Lee
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Alexa R. Soares
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Yu Sun
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Caroline Fai
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508, USA
| | - Marina R. Picciotto
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Junjie U. Guo
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| |
Collapse
|
14
|
Mao Y, Qian SB. Making sense of mRNA translational "noise". Semin Cell Dev Biol 2024; 154:114-122. [PMID: 36925447 PMCID: PMC10500040 DOI: 10.1016/j.semcdb.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 03/15/2023]
Abstract
The importance of translation fidelity has been apparent since the discovery of genetic code. It is commonly believed that translation deviating from the main coding region is to be avoided at all times inside cells. However, ribosome profiling and mass spectrometry have revealed pervasive noncanonical translation. Both the scope and origin of translational "noise" are just beginning to be appreciated. Although largely overlooked, those translational "noises" are associated with a wide range of cellular functions, such as producing unannotated protein products. Furthermore, the dynamic nature of translational "noise" is responsive to stress conditions, highlighting the beneficial effect of translational "noise" in stress adaptation. Mechanistic investigation of translational "noise" will provide better insight into the mechanisms of translational regulation. Ultimately, they are not "noise" at all but represent a signature of cellular activities under pathophysiological conditions. Deciphering translational "noise" holds the therapeutic and diagnostic potential in a wide spectrum of human diseases.
Collapse
Affiliation(s)
- Yuanhui Mao
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|
15
|
Coller J, Ignatova Z. tRNA therapeutics for genetic diseases. Nat Rev Drug Discov 2024; 23:108-125. [PMID: 38049504 DOI: 10.1038/s41573-023-00829-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2023] [Indexed: 12/06/2023]
Abstract
Transfer RNAs (tRNAs) have a crucial role in protein synthesis, and in recent years, their therapeutic potential for the treatment of genetic diseases - primarily those associated with a mutation altering mRNA translation - has gained significant attention. Engineering tRNAs to readthrough nonsense mutation-associated premature termination of mRNA translation can restore protein synthesis and function. In addition, supplementation of natural tRNAs can counteract effects of missense mutations in proteins crucial for tRNA biogenesis and function in translation. This Review will present advances in the development of tRNA therapeutics with high activity and safety in vivo and discuss different formulation approaches for single or chronic treatment modalities. The field of tRNA therapeutics is still in its early stages, and a series of challenges related to tRNA efficacy and stability in vivo, delivery systems with tissue-specific tropism, and safe and efficient manufacturing need to be addressed.
Collapse
Affiliation(s)
- Jeff Coller
- Department of Molecular Biology and Genetics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
| |
Collapse
|
16
|
Richardson MO, Eddy SR. ORFeus: a computational method to detect programmed ribosomal frameshifts and other non-canonical translation events. BMC Bioinformatics 2023; 24:471. [PMID: 38093195 PMCID: PMC10720069 DOI: 10.1186/s12859-023-05602-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND In canonical protein translation, ribosomes initiate translation at a specific start codon, maintain a single reading frame throughout elongation, and terminate at the first in-frame stop codon. However, ribosomal behavior can deviate at each of these steps, sometimes in a programmed manner. Certain mRNAs contain sequence and structural elements that cause ribosomes to begin translation at alternative start codons, shift reading frame, read through stop codons, or reinitiate on the same mRNA. These processes represent important translational control mechanisms that can allow an mRNA to encode multiple functional protein products or regulate protein expression. The prevalence of these events remains uncertain, due to the difficulty of systematic detection. RESULTS We have developed a computational model to infer non-canonical translation events from ribosome profiling data. CONCLUSION ORFeus identifies known examples of alternative open reading frames and recoding events across different organisms and enables transcriptome-wide searches for novel events.
Collapse
Affiliation(s)
- Mary O Richardson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Sean R Eddy
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
| |
Collapse
|
17
|
Kolakada D, Campbell AE, Baquero Galvis L, Li Z, Lore M, Jagannathan S. A system of reporters for comparative investigation of EJC-independent and EJC-enhanced nonsense-mediated mRNA decay. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.567061. [PMID: 38014198 PMCID: PMC10680754 DOI: 10.1101/2023.11.14.567061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Nonsense-mediated mRNA decay (NMD) is a network of pathways that degrades transcripts that undergo premature translation termination. In mammals, NMD can be divided into the exon junction complex (EJC)-enhanced and EJC-independent branches. Fluorescence- and luminescence-based reporters have long been effective tools to investigate NMD, yet existing reporters largely focus on the EJC-enhanced pathway. Here, we present a system of reporters for comparative studies of EJC-independent and EJC-enhanced NMD. This system also enables the study of NMD-associated outcomes such as premature termination codon (PTC) readthrough and truncated protein degradation. These reporters are compatible with fluorescence or luminescence-based readouts via transient transfection or stable integration. Using this reporter system, we show that EJC-enhanced NMD RNA levels are reduced by 2- or 9-fold and protein levels are reduced by 7- or 12-fold compared to EJC-independent NMD, depending on the reporter gene used. Additionally, the extent of readthrough induced by G418 and SMG1i, alone and in combination, varies across NMD substrates. When combined, G418 and SMG1i increase readthrough product levels in an additive manner for EJC-independent reporters, while EJC-enhanced reporters show a synergistic effect. We present these reporters as a valuable toolkit to deepen our understanding of NMD and its associated mechanisms.
Collapse
Affiliation(s)
- Divya Kolakada
- Molecular Biology Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Amy E. Campbell
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Laura Baquero Galvis
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Zhongyou Li
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mlana Lore
- Molecular Biology Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sujatha Jagannathan
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| |
Collapse
|
18
|
Tierney JAS, Świrski M, Tjeldnes H, Mudge JM, Kufel J, Whiffin N, Valen E, Baranov PV. Ribosome Decision Graphs for the Representation of Eukaryotic RNA Translation Complexity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.10.566564. [PMID: 37986835 PMCID: PMC10659439 DOI: 10.1101/2023.11.10.566564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The application of ribosome profiling has revealed an unexpected abundance of translation in addition to that responsible for the synthesis of previously annotated protein-coding regions. Multiple short sequences have been found to be translated within single RNA molecules, both within annotated protein-coding and non-coding regions. The biological significance of this translation is a matter of intensive investigation. However, current schematic or annotation-based representations of mRNA translation generally do not account for the apparent multitude of translated regions within the same molecules. They also do not take into account the stochasticity of the process that allows alternative translations of the same RNA molecules by different ribosomes. There is a need for formal representations of mRNA complexity that would enable the analysis of quantitative information on translation and more accurate models for predicting the phenotypic effects of genetic variants affecting translation. To address this, we developed a conceptually novel abstraction that we term Ribosome Decision Graphs (RDGs). RDGs represent translation as multiple ribosome paths through untranslated and translated mRNA segments. We termed the later 'translons'. Non-deterministic events, such as initiation, re-initiation, selenocysteine insertion or ribosomal frameshifting are then represented as branching points. This representation allows for an adequate representation of eukaryotic translation complexity and focuses on locations critical for translation regulation. We show how RDGs can be used for depicting translated regions, analysis of genetic variation and quantitative genome-wide data on translation for characterisation of regulatory modulators of translation.
Collapse
Affiliation(s)
- Jack A S Tierney
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- SFI Centre for Research Training in Genomics Data Science, University College Cork, Cork, Ireland
| | - Michał Świrski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Håkon Tjeldnes
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Nicola Whiffin
- The Big Data Institute and Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Eivind Valen
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| |
Collapse
|
19
|
Müller MBD, Kasturi P, Jayaraj GG, Hartl FU. Mechanisms of readthrough mitigation reveal principles of GCN1-mediated translational quality control. Cell 2023:S0092-8674(23)00587-1. [PMID: 37339632 PMCID: PMC10364623 DOI: 10.1016/j.cell.2023.05.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 05/17/2023] [Accepted: 05/24/2023] [Indexed: 06/22/2023]
Abstract
Readthrough into the 3' untranslated region (3' UTR) of the mRNA results in the production of aberrant proteins. Metazoans efficiently clear readthrough proteins, but the underlying mechanisms remain unknown. Here, we show in Caenorhabditis elegans and mammalian cells that readthrough proteins are targeted by a coupled, two-level quality control pathway involving the BAG6 chaperone complex and the ribosome-collision-sensing protein GCN1. Readthrough proteins with hydrophobic C-terminal extensions (CTEs) are recognized by SGTA-BAG6 and ubiquitylated by RNF126 for proteasomal degradation. Additionally, cotranslational mRNA decay initiated by GCN1 and CCR4/NOT limits the accumulation of readthrough products. Unexpectedly, selective ribosome profiling uncovered a general role of GCN1 in regulating translation dynamics when ribosomes collide at nonoptimal codons, enriched in 3' UTRs, transmembrane proteins, and collagens. GCN1 dysfunction increasingly perturbs these protein classes during aging, resulting in mRNA and proteome imbalance. Our results define GCN1 as a key factor acting during translation in maintaining protein homeostasis.
Collapse
Affiliation(s)
- Martin B D Müller
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Prasad Kasturi
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Gopal G Jayaraj
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
| |
Collapse
|
20
|
Carollo PS, Tutone M, Culletta G, Fiduccia I, Corrao F, Pibiri I, Di Leonardo A, Zizzo MG, Melfi R, Pace A, Almerico AM, Lentini L. Investigating the Inhibition of FTSJ1, a Tryptophan tRNA-Specific 2'-O-Methyltransferase by NV TRIDs, as a Mechanism of Readthrough in Nonsense Mutated CFTR. Int J Mol Sci 2023; 24:9609. [PMID: 37298560 PMCID: PMC10253411 DOI: 10.3390/ijms24119609] [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: 04/18/2023] [Revised: 05/19/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Cystic Fibrosis (CF) is an autosomal recessive genetic disease caused by mutations in the CFTR gene, coding for the CFTR chloride channel. About 10% of the CFTR gene mutations are "stop" mutations that generate a premature termination codon (PTC), thus synthesizing a truncated CFTR protein. A way to bypass PTC relies on ribosome readthrough, which is the ribosome's capacity to skip a PTC, thus generating a full-length protein. "TRIDs" are molecules exerting ribosome readthrough; for some, the mechanism of action is still under debate. We investigate a possible mechanism of action (MOA) by which our recently synthesized TRIDs, namely NV848, NV914, and NV930, could exert their readthrough activity by in silico analysis and in vitro studies. Our results suggest a likely inhibition of FTSJ1, a tryptophan tRNA-specific 2'-O-methyltransferase.
Collapse
Affiliation(s)
| | - Marco Tutone
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy; (P.S.C.); (G.C.); (I.F.); (F.C.); (I.P.); (A.D.L.); (M.G.Z.); (R.M.); (A.P.); (A.M.A.)
| | | | | | | | | | | | | | | | | | | | - Laura Lentini
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy; (P.S.C.); (G.C.); (I.F.); (F.C.); (I.P.); (A.D.L.); (M.G.Z.); (R.M.); (A.P.); (A.M.A.)
| |
Collapse
|
21
|
Rodnina MV. Decoding and Recoding of mRNA Sequences by the Ribosome. Annu Rev Biophys 2023; 52:161-182. [PMID: 37159300 DOI: 10.1146/annurev-biophys-101922-072452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Faithful translation of messenger RNA (mRNA) into protein is essential to maintain protein homeostasis in the cell. Spontaneous translation errors are very rare due to stringent selection of cognate aminoacyl transfer RNAs (tRNAs) and the tight control of the mRNA reading frame by the ribosome. Recoding events, such as stop codon readthrough, frameshifting, and translational bypassing, reprogram the ribosome to make intentional mistakes and produce alternative proteins from the same mRNA. The hallmark of recoding is the change of ribosome dynamics. The signals for recoding are built into the mRNA, but their reading depends on the genetic makeup of the cell, resulting in cell-specific changes in expression programs. In this review, I discuss the mechanisms of canonical decoding and tRNA-mRNA translocation; describe alternative pathways leading to recoding; and identify the links among mRNA signals, ribosome dynamics, and recoding.
Collapse
Affiliation(s)
- Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany;
| |
Collapse
|
22
|
Jia GS, Zhang WC, Liang Y, Liu XH, Rhind N, Pidoux A, Brysch-Herzberg M, Du LL. A high-quality reference genome for the fission yeast Schizosaccharomyces osmophilus. G3 (BETHESDA, MD.) 2023; 13:jkad028. [PMID: 36748990 PMCID: PMC10085805 DOI: 10.1093/g3journal/jkad028] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 02/08/2023]
Abstract
Fission yeasts are an ancient group of fungal species that diverged from each other from tens to hundreds of million years ago. Among them is the preeminent model organism Schizosaccharomyces pombe, which has significantly contributed to our understandings of molecular mechanisms underlying fundamental cellular processes. The availability of the genomes of S. pombe and 3 other fission yeast species S. japonicus, S. octosporus, and S. cryophilus has enabled cross-species comparisons that provide insights into the evolution of genes, pathways, and genomes. Here, we performed genome sequencing on the type strain of the recently identified fission yeast species S. osmophilus and obtained a complete mitochondrial genome and a nuclear genome assembly with gaps only at rRNA gene arrays. A total of 5,098 protein-coding nuclear genes were annotated and orthologs for more than 95% of them were identified. Genome-based phylogenetic analysis showed that S. osmophilus is most closely related to S. octosporus and these 2 species diverged around 16 million years ago. To demonstrate the utility of this S. osmophilus reference genome, we conducted cross-species comparative analyses of centromeres, telomeres, transposons, the mating-type region, Cbp1 family proteins, and mitochondrial genomes. These analyses revealed conservation of repeat arrangements and sequence motifs in centromere cores, identified telomeric sequences composed of 2 types of repeats, delineated relationships among Tf1/sushi group retrotransposons, characterized the evolutionary origins and trajectories of Cbp1 family domesticated transposases, and discovered signs of interspecific transfer of 2 types of mitochondrial selfish elements.
Collapse
Affiliation(s)
- Guo-Song Jia
- National Institute of Biological Sciences, Beijing 102206, China
| | - Wen-Cai Zhang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Yue Liang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Xi-Han Liu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Nicholas Rhind
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Alison Pidoux
- Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - Michael Brysch-Herzberg
- Laboratory for Wine Microbiology, Department International Business, Heilbronn University, Heilbronn 74081, Germany
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| |
Collapse
|
23
|
Wagner RN, Wießner M, Friedrich A, Zandanell J, Breitenbach-Koller H, Bauer JW. Emerging Personalized Opportunities for Enhancing Translational Readthrough in Rare Genetic Diseases and Beyond. Int J Mol Sci 2023; 24:6101. [PMID: 37047074 PMCID: PMC10093890 DOI: 10.3390/ijms24076101] [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: 02/16/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Nonsense mutations trigger premature translation termination and often give rise to prevalent and rare genetic diseases. Consequently, the pharmacological suppression of an unscheduled stop codon represents an attractive treatment option and is of high clinical relevance. At the molecular level, the ability of the ribosome to continue translation past a stop codon is designated stop codon readthrough (SCR). SCR of disease-causing premature termination codons (PTCs) is minimal but small molecule interventions, such as treatment with aminoglycoside antibiotics, can enhance its frequency. In this review, we summarize the current understanding of translation termination (both at PTCs and at cognate stop codons) and highlight recently discovered pathways that influence its fidelity. We describe the mechanisms involved in the recognition and readthrough of PTCs and report on SCR-inducing compounds currently explored in preclinical research and clinical trials. We conclude by reviewing the ongoing attempts of personalized nonsense suppression therapy in different disease contexts, including the genetic skin condition epidermolysis bullosa.
Collapse
Affiliation(s)
- Roland N. Wagner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | - Michael Wießner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | - Andreas Friedrich
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
- Department of Biosciences, University of Salzburg, 5020 Salzburg, Austria
| | - Johanna Zandanell
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | | | - Johann W. Bauer
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| |
Collapse
|
24
|
Abstract
Although differential transcription drives the development of multicellular organisms, the ultimate readout of a protein-coding gene is ribosome-dependent mRNA translation. Ribosomes were once thought of as uniform molecular machines, but emerging evidence indicates that the complexity and diversity of ribosome biogenesis and function should be given a fresh look in the context of development. This Review begins with a discussion of different developmental disorders that have been linked with perturbations in ribosome production and function. We then highlight recent studies that reveal how different cells and tissues exhibit variable levels of ribosome production and protein synthesis, and how changes in protein synthesis capacity can influence specific cell fate decisions. We finish by touching upon ribosome heterogeneity in stress responses and development. These discussions highlight the importance of considering both ribosome levels and functional specialization in the context of development and disease.
Collapse
Affiliation(s)
- Chunyang Ni
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| |
Collapse
|
25
|
Manjunath LE, Singh A, Som S, Eswarappa SM. Mammalian proteome expansion by stop codon readthrough. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1739. [PMID: 35570338 DOI: 10.1002/wrna.1739] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 04/11/2022] [Accepted: 04/16/2022] [Indexed: 12/20/2022]
Abstract
Recognition of a stop codon by translation machinery as a sense codon results in translational readthrough instead of termination. This recoding process, termed stop codon readthrough (SCR) or translational readthrough, is found in all domains of life including mammals. The context of the stop codon, local mRNA topology, and molecules that interact with the mRNA region downstream of the stop codon determine SCR. The products of SCR can have localization, stability, and function different from those of the canonical isoforms. In this review, we discuss how recent technological and computational advances have increased our understanding of the SCR process in the mammalian system. Based on the known molecular events that occur during SCR of multiple mRNAs, we propose transient molecular roadblocks on an mRNA downstream of the stop codon as a possible mechanism for the induction of SCR. We argue, with examples, that the insights gained from the natural SCR events can guide us to develop novel strategies for the treatment of diseases caused by premature stop codons. This article is categorized under: Translation > Regulation.
Collapse
Affiliation(s)
- Lekha E Manjunath
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Anumeha Singh
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Saubhik Som
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Sandeep M Eswarappa
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka, India
| |
Collapse
|
26
|
Zsurka G, Appel MLT, Nastaly M, Hallmann K, Hansen N, Nass D, Baumgartner T, Surges R, Hartmann G, Bartok E, Kunz WS. Loss of the Immunomodulatory Transcription Factor BATF2 in Humans Is Associated with a Neurological Phenotype. Cells 2023; 12:227. [PMID: 36672163 PMCID: PMC9856319 DOI: 10.3390/cells12020227] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/21/2022] [Accepted: 12/31/2022] [Indexed: 01/06/2023] Open
Abstract
Epilepsy and mental retardation are known to be associated with pathogenic mutations in a broad range of genes that are expressed in the brain and have a role in neurodevelopment. Here, we report on a family with three affected individuals whose clinical symptoms closely resemble a neurodevelopmental disorder. Whole-exome sequencing identified a homozygous stop-gain mutation, p.Gln19*, in the BATF2 gene in the patients. The BATF2 transcription factor is predominantly expressed in macrophages and monocytes and has been reported to modulate AP-1 transcription factor-mediated pro-inflammatory responses. Transcriptome analysis showed altered base-level expression of interferon-stimulated genes in the patients' blood, typical for type I interferonopathies. Peripheral blood mononuclear cells from all three patients demonstrated elevated responses to innate immune stimuli, which could be reproduced in CRISPR-Cas9-generated BATF2-/- human monocytic cell lines. BATF2 is, therefore, a novel disease-associated gene candidate for severe epilepsy and mental retardation related to dysregulation of immune responses, which underscores the relevance of neuroinflammation for epilepsy.
Collapse
Affiliation(s)
- Gábor Zsurka
- Institute of Experimental Epileptology and Cognition Research, Medical Faculty, University of Bonn, 53127 Bonn, Germany
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Maximilian L. T. Appel
- Institute of Clinical Chemistry and Clinical Pharmacology, Medical Faculty, University of Bonn, 53127 Bonn, Germany
- Institute of Experimental Haematology and Transfusion Medicine, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Maximilian Nastaly
- Institute of Clinical Chemistry and Clinical Pharmacology, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Kerstin Hallmann
- Institute of Experimental Epileptology and Cognition Research, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Niels Hansen
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Daniel Nass
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Tobias Baumgartner
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Rainer Surges
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Gunther Hartmann
- Institute of Clinical Chemistry and Clinical Pharmacology, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Eva Bartok
- Institute of Experimental Haematology and Transfusion Medicine, Medical Faculty, University of Bonn, 53127 Bonn, Germany
- Unit of Experimental Immunology, Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
| | - Wolfram S. Kunz
- Institute of Experimental Epileptology and Cognition Research, Medical Faculty, University of Bonn, 53127 Bonn, Germany
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| |
Collapse
|
27
|
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.
Collapse
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.
| |
Collapse
|
28
|
Guo R, Yu X, Gregory BD. The identification of conserved sequence features of co-translationally decayed mRNAs and upstream open reading frames in angiosperm transcriptomes. PLANT DIRECT 2023; 7:e479. [PMID: 36643787 PMCID: PMC9831718 DOI: 10.1002/pld3.479] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
RNA turnover is essential in maintaining messenger RNA (mRNA) homeostasis during various developmental stages and stress responses. Co-translational mRNA decay (CTRD), a process in which mRNAs are degraded while still associated with translating ribosomes, has recently been discovered to function in yeast and three angiosperm transcriptomes. However, it is still unclear how prevalent CTRD across the plant lineage. Moreover, the sequence features of co-translationally decayed mRNAs have not been well-studied. Here, utilizing a collection of publicly available degradome sequencing datasets for another seven angiosperm transcriptomes, we have confirmed that CTRD is functioning in at least 10 angiosperms and likely throughout the plant lineage. Additionally, we have identified sequence features shared by the co-translationally decayed mRNAs in these species, implying a possible conserved triggering mechanism for this pathway. Given that degradome sequencing datasets can also be used to identify actively translating upstream open reading frames (uORFs), which are quite understudied in plants, we have identified numerous actively translating uORFs in the same 10 angiosperms. These findings reveal that actively translating uORFs are prevalent in plant transcriptomes, some of which are conserved across this lineage. We have also observed conserved sequence features in the regions flanking these uORFs' stop codons that might contribute to ribosome stalling at these sequences. Finally, we discovered that there were very few overlaps between the mRNAs harboring actively translating uORFs and those sorted into the co-translational decay pathway in the majority of the studied angiosperms, suggesting that these two processes might be nearly mutually exclusive in those species. In total, our findings provide the identification of CTRD and actively translating uORFs across a broad collection of plants and provide novel insights into the important sequence features associated with these collections of mRNAs and regulatory elements, respectively.
Collapse
Affiliation(s)
- Rong Guo
- Department of BiologyUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Xiang Yu
- Department of BiologyUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Present address:
School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Brian D. Gregory
- Department of BiologyUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| |
Collapse
|
29
|
Loughran G, Li X, O’Loughlin S, Atkins JF, Baranov P. Monitoring translation in all reading frames downstream of weak stop codons provides mechanistic insights into the impact of nucleotide and cellular contexts. Nucleic Acids Res 2022; 51:304-314. [PMID: 36533511 PMCID: PMC9841425 DOI: 10.1093/nar/gkac1180] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 11/08/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022] Open
Abstract
A stop codon entering the ribosome A-site is normally decoded by release factors that induce release of the polypeptide. Certain factors influence the efficiency of the termination which is in competition with elongation in either the same (readthrough) or an alternative (frameshifting) reading frame. To gain insight into the competition between these processes, we monitored translation in parallel from all three reading frames downstream of stop codons while changing the nucleotide context of termination sites or altering cellular conditions (polyamine levels). We found that P-site codon identity can have a major impact on the termination efficiency of the OPRL1 stop signal, whereas for the OAZ1 ORF1 stop signal, the P-site codon mainly influences the reading frame of non-terminating ribosomes. Changes to polyamine levels predominantly influence the termination efficiency of the OAZ1 ORF1 stop signal. In contrast, increasing polyamine levels stimulate readthrough of the OPRL1 stop signal by enhancing near-cognate decoding rather than by decreasing termination efficiency. Thus, by monitoring the four competing processes occurring at stop codons we were able to determine which is the most significantly affected upon perturbation. This approach may be useful for the interrogation of other recoding phenomena where alternative decoding processes compete with standard decoding.
Collapse
Affiliation(s)
- Gary Loughran
- Correspondence may also be addressed to Gary Loughran.
| | - Xiang Li
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Sinead O’Loughlin
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland,Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | | |
Collapse
|
30
|
Ngiwsara L, Sawangareetrakul P, Wattanasirichaigoon D, Tim-Aroon T, Dejkhamron P, Champattanachai V, Ketudat-Cairns JR, Svasti J. Effects of gentamicin inducing readthrough premature stop Codons: A study of alpha-L-iduronidase nonsense variants in COS-7 Cells. Biochem Biophys Res Commun 2022; 636:147-154. [DOI: 10.1016/j.bbrc.2022.10.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 10/23/2022] [Indexed: 11/02/2022]
|
31
|
Embree CM, Abu-Alhasan R, Singh G. Features and factors that dictate if terminating ribosomes cause or counteract nonsense-mediated mRNA decay. J Biol Chem 2022; 298:102592. [PMID: 36244451 PMCID: PMC9661723 DOI: 10.1016/j.jbc.2022.102592] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a quality control pathway in eukaryotes that continuously monitors mRNA transcripts to ensure truncated polypeptides are not produced. The expression of many normal mRNAs that encode full-length polypeptides is also regulated by this pathway. Such transcript surveillance by NMD is intimately linked to translation termination. When a ribosome terminates translation at a normal termination codon, NMD is not activated, and mRNA can undergo repeated rounds of translation. On the other hand, when translation termination is deemed abnormal, such as that on a premature termination codon, it leads to a series of poorly understood events involving the NMD pathway, which destabilizes the transcript. In this review, we summarize our current understanding of how the NMD machinery interfaces with the translation termination factors to initiate NMD. We also discuss a variety of cis-acting sequence contexts and trans-acting factors that can cause readthrough, ribosome reinitiation, or ribosome frameshifting at stop codons predicted to induce NMD. These alternative outcomes can lead to the ribosome translating downstream of such stop codons and hence the transcript escaping NMD. NMD escape via these mechanisms can have wide-ranging implications on human health, from being exploited by viruses to hijack host cell systems to being harnessed as potential therapeutic possibilities to treat genetic diseases.
Collapse
Affiliation(s)
- Caleb M Embree
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio USA
| | - Rabab Abu-Alhasan
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio USA
| | - Guramrit Singh
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio USA.
| |
Collapse
|
32
|
Sapkota D, Florian C, Doherty BM, White KM, Reardon KM, Ge X, Garbow JR, Yuede CM, Cirrito JR, Dougherty JD. Aqp4 stop codon readthrough facilitates amyloid-β clearance from the brain. Brain 2022; 145:2982-2990. [PMID: 36001414 PMCID: PMC10233234 DOI: 10.1093/brain/awac199] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 05/08/2022] [Accepted: 05/15/2022] [Indexed: 01/07/2023] Open
Abstract
Alzheimer's disease is initiated by the toxic aggregation of amyloid-β. Immunotherapeutics aimed at reducing amyloid beta are in clinical trials but with very limited success to date. Identification of orthogonal approaches for clearing amyloid beta may complement these approaches for treating Alzheimer's disease. In the brain, the astrocytic water channel Aquaporin 4 is involved in clearance of amyloid beta, and the fraction of Aquaporin 4 found perivascularly is decreased in Alzheimer's disease. Further, an unusual stop codon readthrough event generates a conserved C-terminally elongated variant of Aquaporin 4 (AQP4X), which is exclusively perivascular. However, it is unclear whether the AQP4X variant specifically mediates amyloid beta clearance. Here, using Aquaporin 4 readthrough-specific knockout mice that still express normal Aquaporin 4, we determine that this isoform indeed mediates amyloid beta clearance. Further, with high-throughput screening and counterscreening, we identify small molecule compounds that enhance readthrough of the Aquaporin 4 sequence and validate a subset on endogenous astrocyte Aquaporin 4. Finally, we demonstrate these compounds enhance brain amyloid-β clearance in vivo, which depends on AQP4X. This suggests derivatives of these compounds may provide a viable pharmaceutical approach to enhance clearance of amyloid beta and potentially other aggregating proteins in neurodegenerative disease.
Collapse
Affiliation(s)
- Darshan Sapkota
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Colin Florian
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Brookelyn M Doherty
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kelli M White
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kate M Reardon
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Xia Ge
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Intellectual and Developmental Disabilities Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joel R Garbow
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Intellectual and Developmental Disabilities Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
- Alvin J Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Carla M Yuede
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - John R Cirrito
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joseph D Dougherty
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| |
Collapse
|
33
|
Romero Romero ML, Landerer C, Poehls J, Toth‐Petroczy A. Phenotypic mutations contribute to protein diversity and shape protein evolution. Protein Sci 2022; 31:e4397. [PMID: 36040266 PMCID: PMC9375231 DOI: 10.1002/pro.4397] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/14/2022] [Accepted: 07/04/2022] [Indexed: 11/16/2022]
Abstract
Errors in DNA replication generate genetic mutations, while errors in transcription and translation lead to phenotypic mutations. Phenotypic mutations are orders of magnitude more frequent than genetic ones, yet they are less understood. Here, we review the types of phenotypic mutations, their quantifications, and their role in protein evolution and disease. The diversity generated by phenotypic mutation can facilitate adaptive evolution. Indeed, phenotypic mutations, such as ribosomal frameshift and stop codon readthrough, sometimes serve to regulate protein expression and function. Phenotypic mutations have often been linked to fitness decrease and diseases. Thus, understanding the protein heterogeneity and phenotypic diversity caused by phenotypic mutations will advance our understanding of protein evolution and have implications on human health and diseases.
Collapse
Affiliation(s)
- Maria Luisa Romero Romero
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Center for Systems Biology DresdenDresdenGermany
| | - Cedric Landerer
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Center for Systems Biology DresdenDresdenGermany
| | - Jonas Poehls
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Center for Systems Biology DresdenDresdenGermany
| | - Agnes Toth‐Petroczy
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Center for Systems Biology DresdenDresdenGermany
- Cluster of Excellence Physics of LifeTU DresdenDresdenGermany
| |
Collapse
|
34
|
2-Guanidino-quinazoline promotes the readthrough of nonsense mutations underlying human genetic diseases. Proc Natl Acad Sci U S A 2022; 119:e2122004119. [PMID: 35994666 PMCID: PMC9436315 DOI: 10.1073/pnas.2122004119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Nonsense mutations account for approximately 11% of all described gene lesions causing human inherited diseases. This premature termination codon (PTC) leads to the premature arrest of translation that generates a truncated peptide and the degradation of the corresponding mRNA through the nonsense-mediated mRNA decay (NMD) pathway. The possibility of restoring the protein expression by promoting PTC readthrough using drugs appears to be an important therapeutic strategy. Unfortunately, this strategy is limited by the small number of molecules known to promote PTC readthrough without affecting normal translation termination. In this work, we identify a new molecule, TLN468, that promotes a high level of PTC readthrough without a detectable effect on normal stop codons. Premature termination codons (PTCs) account for 10 to 20% of genetic diseases in humans. The gene inactivation resulting from PTCs can be counteracted by the use of drugs stimulating PTC readthrough, thereby restoring production of the full-length protein. However, a greater chemical variety of readthrough inducers is required to broaden the medical applications of this therapeutic strategy. In this study, we developed a reporter cell line and performed high-throughput screening (HTS) to identify potential readthrough inducers. After three successive assays, we isolated 2-guanidino-quinazoline (TLN468). We assessed the clinical potential of this drug as a potent readthrough inducer on the 40 PTCs most frequently responsible for Duchenne muscular dystrophy (DMD). We found that TLN468 was more efficient than gentamicin, and acted on a broader range of sequences, without inducing the readthrough of normal stop codons (TC).
Collapse
|
35
|
Baba H. [Introduction to Myelin Research]. YAKUGAKU ZASSHI 2022; 142:837-853. [PMID: 35908945 DOI: 10.1248/yakushi.21-00224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myelin is a multilamellar membrane structure formed by oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS). It has been recognized as an insulator that is essential for the rapid and efficient propagation of action potentials by saltatory conduction. However, recently many studies have shown that myelin and myelin-forming cells interact with axons and regulate the nervous system far more actively than previously thought. For example, myelination changes axons dynamically and divides them into four distinct functional domains: node of Ranvier, paranode, juxtaparanode, and internode. Voltage-gated Na+ channels are clustered at the node, while K+ channels are at the juxtaparanode, and segregation of these channels by paranodal axoglial junction is necessary for proper axonal function. My research experience began at the neurology ward of the Niigata University Medical Hospital, where I saw a patient with peripheral neuropathy of unknown etiology more than 37 years ago. In the patient's serum, we found an autoantibody against a glycolipid enriched in the PNS. Since then, I have been interested in myelin because of its beautiful structure and unique roles in the nervous system. In this review, our recent studies related to CNS and PNS myelin are presented.
Collapse
Affiliation(s)
- Hiroko Baba
- Department of Molecular Neurobiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| |
Collapse
|
36
|
Lombardi S, Testa MF, Pinotti M, Branchini A. Translation termination codons in protein synthesis and disease. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 132:1-48. [PMID: 36088072 DOI: 10.1016/bs.apcsb.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fidelity of protein synthesis, a process shaped by several mechanisms involving specialized ribosome regions and external factors, ensures the precise reading of sense as well as stop codons (UGA, UAG, UAA), which are usually localized at the 3' of mRNA and drive the release of the polypeptide chain. However, either natural (NTCs) or premature (PTCs) termination codons, the latter arising from nucleotide changes, can undergo a recoding process named ribosome or translational readthrough, which insert specific amino acids (NTCs) or subset(s) depending on the stop codon type (PTCs). This process is particularly relevant for nonsense mutations, a relatively frequent cause of genetic disorders, which impair gene expression at different levels by potentially leading to mRNA degradation and/or synthesis of truncated proteins. As a matter of fact, many efforts have been made to develop efficient and safe readthrough-inducing compounds, which have been challenged in several models of human disease to provide with a therapy. In this view, the dissection of the molecular determinants shaping the outcome of readthrough, namely nucleotide and protein contexts as well as their interplay and impact on protein structure/function, is crucial to identify responsive nonsense mutations resulting in functional full-length proteins. The interpretation of experimental and mechanistic findings is also important to define a possibly clear picture of potential readthrough-favorable features useful to achieve rescue profiles compatible with therapeutic thresholds typical of each targeted disorder, which is of primary importance for the potential translatability of readthrough into a personalized and mutation-specific, and thus patient-oriented, therapeutic strategy.
Collapse
Affiliation(s)
- Silvia Lombardi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Maria Francesca Testa
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Alessio Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
| |
Collapse
|
37
|
Sahoo S, Singh D, Singh A, Pandit M, Vasu K, Som S, Pullagurla NJ, Laha D, Eswarappa SM. Identification and functional characterization of mRNAs that exhibit stop codon readthrough in Arabidopsis thaliana. J Biol Chem 2022; 298:102173. [PMID: 35752360 PMCID: PMC9293766 DOI: 10.1016/j.jbc.2022.102173] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 06/16/2022] [Accepted: 06/18/2022] [Indexed: 11/29/2022] Open
Abstract
Stop codon readthrough (SCR) is the process of continuation of translation beyond the stop codon, generating protein isoforms with C-terminal extensions. SCR has been observed in viruses, fungi, and multicellular organisms, including mammals. However, SCR is largely unexplored in plants. In this study, we have analyzed ribosome profiling datasets to identify mRNAs that exhibit SCR in Arabidopsis thaliana. Analyses of the ribosome density, ribosome coverage, and three-nucleotide periodicity of the ribosome profiling reads in the mRNA region downstream of the stop codon provided strong evidence for SCR in mRNAs of 144 genes. We show that SCR generated putative evolutionarily conserved nuclear localization signals, transmembrane helices, and intrinsically disordered regions in the C-terminal extensions of several of these proteins. Furthermore, gene ontology (GO) functional enrichment analysis revealed that these 144 genes belong to three major functional groups - translation, photosynthesis, and abiotic stress tolerance. Using a luminescence-based readthrough assay, we experimentally demonstrated SCR in representative mRNAs belonging to each of these functional classes. Finally, using microscopy, we show that the SCR product of one gene that contains a nuclear localization signal at the C-terminal extension, CURT1B, localizes to the nucleus as predicted. Based on these observations, we propose that SCR plays an important role in plant physiology by regulating protein localization and function.
Collapse
Affiliation(s)
- Sarthak Sahoo
- Undergraduate Program, Indian Institute of Science, Bengaluru, India; Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Divyoj Singh
- Undergraduate Program, Indian Institute of Science, Bengaluru, India
| | - Anumeha Singh
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Madhuparna Pandit
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Kirtana Vasu
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Saubhik Som
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | | | - Debabrata Laha
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | | |
Collapse
|
38
|
Biziaev N, Sokolova E, Yanvarev DV, Toropygin IY, Shuvalov A, Egorova T, Alkalaeva E. Recognition of 3' nucleotide context and stop codon readthrough are determined during mRNA translation elongation. J Biol Chem 2022; 298:102133. [PMID: 35700825 PMCID: PMC9272376 DOI: 10.1016/j.jbc.2022.102133] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 11/16/2022] Open
Abstract
The nucleotide context surrounding stop codons significantly affects the efficiency of translation termination. In eukaryotes, various 3′ contexts that are unfavorable for translation termination have been described; however, the exact molecular mechanism that mediates their effects remains unknown. In this study, we used a reconstituted mammalian translation system to examine the efficiency of stop codons in different contexts, including several previously described weak 3′ stop codon contexts. We developed an approach to estimate the level of stop codon readthrough in the absence of eukaryotic release factors (eRFs). In this system, the stop codon is recognized by the suppressor or near-cognate tRNAs. We observed that in the absence of eRFs, readthrough occurs in a 3′ nucleotide context-dependent manner, and the main factors determining readthrough efficiency were the type of stop codon and the sequence of the 3′ nucleotides. Moreover, the efficiency of translation termination in weak 3′ contexts was almost equal to that in the tested standard context. Therefore, the ability of eRFs to recognize stop codons and induce peptide release is not affected by mRNA context. We propose that ribosomes or other participants of the elongation cycle can independently recognize certain contexts and increase the readthrough of stop codons. Thus, the efficiency of translation termination is regulated by the 3′ nucleotide context following the stop codon and depends on the concentrations of eRFs and suppressor/near-cognate tRNAs.
Collapse
Affiliation(s)
- Nikita Biziaev
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Elizaveta Sokolova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Dmitry V Yanvarev
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Ilya Yu Toropygin
- Orekhovich Research Institute of Biomedical Chemistry, Moscow, 119992, Russia.
| | - Alexey Shuvalov
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia.
| | - Tatiana Egorova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; Pirogov Russian National Research Medical University, Moscow, 117997, Russia.
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia.
| |
Collapse
|
39
|
Wang X, Dong Q, Chen G, Zhang J, Liu Y, Cai Y. Frameshift and wild-type proteins are often highly similar because the genetic code and genomes were optimized for frameshift tolerance. BMC Genomics 2022; 23:416. [PMID: 35655139 PMCID: PMC9164415 DOI: 10.1186/s12864-022-08435-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 03/02/2022] [Indexed: 11/10/2022] Open
Abstract
Frameshift mutations have been considered of significant importance for the molecular evolution of proteins and their coding genes, while frameshift protein sequences encoded in the alternative reading frames of coding genes have been considered to be meaningless. However, functional frameshifts have been found widely existing. It was puzzling how a frameshift protein kept its structure and functionality while substantial changes occurred in its primary amino-acid sequence. This study shows that the similarities among frameshifts and wild types are higher than random similarities and are determined at different levels. Frameshift substitutions are more conservative than random substitutions in the standard genetic code (SGC). The frameshift substitutions score of SGC ranks in the top 2.0-3.5% of alternative genetic codes, showing that SGC is nearly optimal for frameshift tolerance. In many genes and certain genomes, frameshift-resistant codons and codon pairs appear more frequently than expected, suggesting that frameshift tolerance is achieved through not only the optimality of the genetic code but, more importantly, the further optimization of a specific gene or genome through the usages of codons/codon pairs, which sheds light on the role of frameshift mutations in molecular and genomic evolution.
Collapse
|
40
|
Christensen MB, Levy AM, Mohammadi NA, Niceta M, Kaiyrzhanov R, Dentici ML, Alam CA, Alesi V, Benoit V, Bhatia KP, Bierhals T, Boßelmann CM, Buratti J, Callewaert B, Ceulemans B, Charles P, De Wachter M, Dehghani M, D'haenens E, Doco-Fenzy M, Geßner M, Gobert C, Guliyeva U, Haack TB, Hammer TB, Heinrich T, Hempel M, Herget T, Hoffmann U, Horvath J, Houlden H, Keren B, Kresge C, Kumps C, Lederer D, Lermine A, Magrinelli F, Maroofian R, Mehrjardi MYV, Moudi M, Müller AJ, Oostra AJ, Pletcher BA, Ros-Pardo D, Samarasekera S, Tartaglia M, Van Schil K, Vogt J, Wassmer E, Winkelmann J, Zaki MS, Zech M, Lerche H, Radio FC, Gomez-Puertas P, Møller RS, Tümer Z. Biallelic variants in ZNF142 lead to a syndromic neurodevelopmental disorder. Clin Genet 2022; 102:98-109. [PMID: 35616059 PMCID: PMC9546172 DOI: 10.1111/cge.14165] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/10/2022] [Accepted: 05/16/2022] [Indexed: 11/28/2022]
Abstract
Biallelic variants of the gene encoding for the zinc-finger protein 142 (ZNF142) have recently been associated with intellectual disability (ID), speech impairment, seizures, and movement disorders in nine individuals from five families. In this study, we obtained phenotype and genotype information of 26 further individuals from 16 families. Among the 27 different ZNF142 variants identified in the total of 35 individuals only four were missense. Missense variants may give a milder phenotype by changing the local structure of ZF motifs as suggested by protein modelling; but this correlation should be validated in larger cohorts and pathogenicity of the missense variants should be investigated with functional studies. Clinical features of the 35 individuals suggest that biallelic ZNF142 variants lead to a syndromic neurodevelopmental disorder with mild to moderate ID, varying degrees of delay in language and gross motor development, early onset seizures, hypotonia, behavioral features, movement disorders, and facial dysmorphism. The differences in symptom frequencies observed in the unpublished individuals compared to those of published, and recognition of previously underemphasized facial features are likely to be due to the small sizes of the previous cohorts, which underlines the importance of larger cohorts for the phenotype descriptions of rare genetic disorders. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Maria B Christensen
- Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Amanda M Levy
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Nazanin A Mohammadi
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Marcello Niceta
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Rauan Kaiyrzhanov
- Department of Neuromuscular Disorders, University College London Institute of Neurology, London, United Kingdom
| | - Maria Lisa Dentici
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy.,Medical Genetics Unit, Academic Department of Pediatrics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Chadi Al Alam
- Pediatric Neurology department, American center for Psychiatry and Neurology, Abu Dhabi and Al Ain, United Arab Emirates.,Pediatric Neurology department, Haykel Hospital, El Koura, Lebanon
| | - Viola Alesi
- Translational Cytogenomics Research Unit, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | - Kailash P Bhatia
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian M Boßelmann
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Julien Buratti
- Department of Medical Genetics, Pitié-Salpêtrière Hospital, AP- HP, Sorbonne Université, Paris, France
| | - Bert Callewaert
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Berten Ceulemans
- Department of Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Perrine Charles
- Department of Medical Genetics, Pitié-Salpêtrière Hospital, AP- HP, Sorbonne Université, Paris, France
| | - Matthias De Wachter
- Department of Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Mohammadreza Dehghani
- Medical Genetics Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Erika D'haenens
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Martine Doco-Fenzy
- SFR CAP SANTE, HMB2 CHU, Reims, France.,CHU de Nantes, service de génétique médicale, Nantes, France
| | - Michaela Geßner
- KfH-Board of Trustees for Dialysis and Kidney Transplantation (KfH-Kuratorium für Dialyse und Nierentransplantation e.V.), Neu Isenburg, Germany
| | - Cyrielle Gobert
- Neuropediatric department, Centre Hospitalier Neurologique William Lennox, Ottignies, Belgium
| | | | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.,Centre for Rare Diseases, University of Tübingen, Tübingen, Germany
| | - Trine B Hammer
- Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre, Dianalund, Denmark
| | - Tilman Heinrich
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.,MVZ Humangenetik und Molekularpathologie GmbH, Rostock, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Theresia Herget
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Judit Horvath
- Institute of Human Genetics, University of Münster, Münster, Germany
| | - Henry Houlden
- Department of Neuromuscular Disorders, University College London Institute of Neurology, London, United Kingdom
| | - Boris Keren
- Department of Medical Genetics, Pitié-Salpêtrière Hospital, AP- HP, Sorbonne Université, Paris, France
| | | | - Candy Kumps
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | | | | | - Francesca Magrinelli
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Reza Maroofian
- Department of Neuromuscular Disorders, University College London Institute of Neurology, London, United Kingdom
| | | | - Mahdiyeh Moudi
- Department of Genetics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amelie J Müller
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Anna J Oostra
- Neuropediatric department, Ghent University Hospital, Ghent, Belgium.,Centre for Developmental disorders, Ghent, Belgium
| | | | - David Ros-Pardo
- Molecular Modeling Group, Centro de Biología Molecular Severo Ochoa, CBMSO (CSIC-UAM), Madrid, Spain
| | | | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Kristof Van Schil
- Department of Medical Genetics, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women's and Children's Hospital, Birmingham, United Kingdom
| | - Evangeline Wassmer
- Birmingham Women and Children's Hospital, Birmingham, United Kingdom.,Institute of Health and Neurodevelopment, Aston University, Birmingham, United Kingdom
| | - Juliane Winkelmann
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany.,Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt.,Genetics Department, Armed Forces College of Medicine (AFCM), Cairo, Egypt
| | - Michael Zech
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany.,Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | | | - Paulino Gomez-Puertas
- Molecular Modeling Group, Centro de Biología Molecular Severo Ochoa, CBMSO (CSIC-UAM), Madrid, Spain
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Zeynep Tümer
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
41
|
Pati R, Palazzo C, Valente O, Abbrescia P, Messina R, Surdo NC, Lefkimmiatis K, Signorelli F, Nicchia GP, Frigeri A. The Readthrough Isoform AQP4ex Is Constitutively Phosphorylated in the Perivascular Astrocyte Endfeet of Human Brain. Biomolecules 2022; 12:633. [PMID: 35625560 PMCID: PMC9138620 DOI: 10.3390/biom12050633] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/17/2022] [Accepted: 04/22/2022] [Indexed: 02/03/2023] Open
Abstract
AQP4ex is a recently discovered isoform of AQP4 generated by a translational readthrough mechanism. It is strongly expressed at the astrocyte perivascular endfeet as a component of the supramolecular membrane complex, commonly called orthogonal array of particles (OAP), together with the canonical isoforms M1 and M23 of AQP4. Previous site-directed mutagenesis experiments suggested the potential role of serine331 and serine335, located in the extended peptide of AQP4ex, in water channel activity by phosphorylation. In the present study we evaluated the effective phosphorylation of human AQP4ex. A small scale bioinformatic analysis indicated that only Ser335 is conserved in human, mouse and rat AQP4ex. The phosphorylation site of Ser335 was assessed through generation of phospho-specific antibodies in rabbits. Antibody specificity was first evaluated in binding phosphorylated peptide versus its unphosphorylated analog by ELISA, which was further confirmed by site-directed mutagenesis experiments. Western blot and immunofluorescence experiments revealed strong expression of phosphorylated AQP4ex (p-AQP4ex) in human brain and localization at the perivascular astrocyte endfeet in supramolecular assemblies identified by BN/PAGE experiments. All together, these data reveal, for the first time, the existence of a phosphorylated form of AQP4, at Ser335 in the extended sequence exclusive of AQP4ex. Therefore, we anticipate an important physiological role of p-AQP4ex in human brain water homeostasis.
Collapse
Affiliation(s)
- Roberta Pati
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (R.P.); (C.P.); (O.V.); (P.A.); (R.M.); (F.S.)
| | - Claudia Palazzo
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (R.P.); (C.P.); (O.V.); (P.A.); (R.M.); (F.S.)
| | - Onofrio Valente
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (R.P.); (C.P.); (O.V.); (P.A.); (R.M.); (F.S.)
| | - Pasqua Abbrescia
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (R.P.); (C.P.); (O.V.); (P.A.); (R.M.); (F.S.)
| | - Raffaella Messina
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (R.P.); (C.P.); (O.V.); (P.A.); (R.M.); (F.S.)
| | - Nicoletta Concetta Surdo
- Foundation for Advanced Biomedical Research, Veneto Institute of Molecular Medicine, 35129 Padova, Italy; (N.C.S.); (K.L.)
- Neuroscience Institute, National Research Council of Italy (CNR), 35129 Padova, Italy
| | - Konstantinos Lefkimmiatis
- Foundation for Advanced Biomedical Research, Veneto Institute of Molecular Medicine, 35129 Padova, Italy; (N.C.S.); (K.L.)
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Francesco Signorelli
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (R.P.); (C.P.); (O.V.); (P.A.); (R.M.); (F.S.)
| | - Grazia Paola Nicchia
- Department of Bioscience, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, 70124 Bari, Italy;
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 840 Kennedy Center, Bronx, NY 10461, USA
| | - Antonio Frigeri
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (R.P.); (C.P.); (O.V.); (P.A.); (R.M.); (F.S.)
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 840 Kennedy Center, Bronx, NY 10461, USA
| |
Collapse
|
42
|
Influence of novel readthrough agents on myelin protein zero translation in the peripheral nervous system. Neuropharmacology 2022; 211:109059. [DOI: 10.1016/j.neuropharm.2022.109059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 02/24/2022] [Accepted: 04/06/2022] [Indexed: 12/22/2022]
|
43
|
Salman MM, Kitchen P, Halsey A, Wang MX, Törnroth-Horsefield S, Conner AC, Badaut J, Iliff JJ, Bill RM. Emerging roles for dynamic aquaporin-4 subcellular relocalization in CNS water homeostasis. Brain 2022; 145:64-75. [PMID: 34499128 PMCID: PMC9088512 DOI: 10.1093/brain/awab311] [Citation(s) in RCA: 111] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 06/28/2021] [Accepted: 07/31/2021] [Indexed: 11/25/2022] Open
Abstract
Aquaporin channels facilitate bidirectional water flow in all cells and tissues. AQP4 is highly expressed in astrocytes. In the CNS, it is enriched in astrocyte endfeet, at synapses, and at the glia limitans, where it mediates water exchange across the blood-spinal cord and blood-brain barriers (BSCB/BBB), and controls cell volume, extracellular space volume, and astrocyte migration. Perivascular enrichment of AQP4 at the BSCB/BBB suggests a role in glymphatic function. Recently, we have demonstrated that AQP4 localization is also dynamically regulated at the subcellular level, affecting membrane water permeability. Ageing, cerebrovascular disease, traumatic CNS injury, and sleep disruption are established and emerging risk factors in developing neurodegeneration, and in animal models of each, impairment of glymphatic function is associated with changes in perivascular AQP4 localization. CNS oedema is caused by passive water influx through AQP4 in response to osmotic imbalances. We have demonstrated that reducing dynamic relocalization of AQP4 to the BSCB/BBB reduces CNS oedema and accelerates functional recovery in rodent models. Given the difficulties in developing pore-blocking AQP4 inhibitors, targeting AQP4 subcellular localization opens up new treatment avenues for CNS oedema, neurovascular and neurodegenerative diseases, and provides a framework to address fundamental questions about water homeostasis in health and disease.
Collapse
Affiliation(s)
- Mootaz M Salman
- Department of Physiology, Anatomy and Genetics,
University of Oxford, Oxford OX1 3PT, UK
| | - Philip Kitchen
- School of Biosciences, College of Health and Life
Sciences, Aston University, Aston Triangle,
Birmingham B4 7ET, UK
| | - Andrea Halsey
- Institute of Clinical Sciences, College of Medical
and Dental Sciences, University of Birmingham,
Edgbaston, Birmingham B15 2TT, UK
| | - Marie Xun Wang
- Department of Psychiatry and Behavioral Sciences,
University of Washington School of Medicine, Seattle, WA, USA
| | | | - Alex C Conner
- Institute of Clinical Sciences, College of Medical
and Dental Sciences, University of Birmingham,
Edgbaston, Birmingham B15 2TT, UK
| | - Jerome Badaut
- CNRS-UMR 5536-Centre de Résonance
Magnétique des systèmes Biologiques, Université de
Bordeaux, 33076 Bordeaux, France
| | - Jeffrey J Iliff
- Department of Psychiatry and Behavioral Sciences,
University of Washington School of Medicine, Seattle, WA, USA
- Department of Neurology, University of Washington
School of Medicine, Seattle, WA, USA
- VISN 20 Mental Illness Research, Education and
Clinical Center, VA Puget Sound Health Care System, Seattle, WA,
USA
| | - Roslyn M Bill
- School of Biosciences, College of Health and Life
Sciences, Aston University, Aston Triangle,
Birmingham B4 7ET, UK
| |
Collapse
|
44
|
A compact and simple method of achieving differential transgene expression by exploiting translational readthrough. Biotechniques 2022; 72:143-154. [PMID: 35234525 DOI: 10.2144/btn-2021-0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The development of multicistronic vectors enabling differential transgene expression is a goal of gene therapy and poses a significant engineering challenge. Current approaches rely on the insertion of long regulatory sequences that occupy valuable space in vectors, which have a finite and limited packaging capacity. Here we describe a simple method of achieving differential transgene expression by inserting stop codons and translational readthrough motifs (TRMs) to suppress stop codon termination. TRMs reduced downstream transgene expression ∼sixfold to ∼140-fold, depending on the combination of stop codon and TRM used. We show that a TRM can facilitate the controlled secretion of the highly potent cytokine IL-12 at therapeutically beneficial levels in an aggressive immunocompetent mouse melanoma model to prevent tumor growth. Given their compact size (6 bp) and ease of introduction, we envisage that TRMs will be widely adopted in recombinant DNA engineering to facilitate differential transgene expression.
Collapse
|
45
|
Valente O, Messina R, Ingravallo G, Bellitti E, Zimatore DS, de Gennaro L, Abbrescia P, Pati R, Palazzo C, Nicchia GP, Trojano M, Signorelli F, Frigeri A. Alteration of the translational readthrough isoform AQP4ex induces redistribution and downregulation of AQP4 in human glioblastoma. Cell Mol Life Sci 2022; 79:140. [PMID: 35187599 PMCID: PMC8858924 DOI: 10.1007/s00018-021-04123-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 12/21/2021] [Accepted: 12/29/2021] [Indexed: 11/03/2022]
Abstract
AbstractGlioblastoma multiforme (GBM) is characterized by a remarkable cellular and molecular heterogeneity that make the behavior of this tumor highly variable and resistant to therapy. In addition, the most serious clinical complication of GBM and other brain tumors is the development of vasogenic edema which dramatically increase the intracranial pressure. In the present study we evaluate the expression, supramolecular organization and spatial distribution of AQP4 and AQP4ex, the new readthrough isoform of AQP4, in relationship with the degree of vasogenic brain edema and tumor progression. To this purpose, tissue samples from regions of tumor core, peritumoral and non-infiltrated tissues of each GBM patient (n = 31) were analyzed. Immunofluorescence experiments revealed that the expression of AQP4ex was almost absent in tumoral regions while the canonical AQP4 isoforms appear mostly delocalized. In peritumoral tissues, AQP4 expression was found altered in those perivascular astrocyte processes where AQP4ex appeared reduced and partially delocalized. Protein expression levels measured by immunoblot showed that global AQP4 was reduced mainly in the tumor core. Notably, the relative amount of AQP4ex was more severely reduced starting from the peritumoral region. BN-PAGE experiments showed that the supramolecular organization of AQP4 is only partially affected in GBM. Edema assessment by magnetic resonance imaging revealed that the level of AQP4ex downregulation correlated with edema severity. Finally, the degree of BBB alteration, measured with sodium fluorescein content in GBM biopsies, correlated with the edema index and AQP4ex downregulation. Altogether these data suggest that the AQP4ex isoform is critical in the triggering event of progressive downregulation and mislocalization of AQP4 in GBM, which may affect the integrity of the BBB and contributes to accumulation of edema in the peritumoral tissue. Thus, AQP4ex could be considered as a potential early biomarker of GBM progression.
Collapse
|
46
|
Yordanova MM, Loughran G, Atkins JF, Baranov PV. Stop codon readthrough contexts influence reporter expression differentially depending on the presence of an IRES. Wellcome Open Res 2022; 5:221. [PMID: 35187266 PMCID: PMC8831848 DOI: 10.12688/wellcomeopenres.16231.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2022] [Indexed: 11/20/2022] Open
Abstract
Background: Previously we reported the discovery of stop codon readthrough in AMD1 mRNA followed by ribosome stalling at the end of a conserved Open Reading Frame (ORF) that we termed AMD1. To explain the severe suppression of reporters fused to AMD1 tail we proposed a mechanism invoking ribosome queueing. In the original study, we tested this hypothesis, by placing the reporter stop codon in the context of readthrough permissive sequences in a dual reporter vector with downstream reporter expression driven by the EMCV IRES. In accordance with our hypothesis, we observed a striking disproportional reduction of upstream reporter activity in response to increased readthrough levels. Methods: Here we employ dual luciferase assays, western blotting and RT-qPCR to explore the effects of test sequences downstream to the reporter stop codon on its expression in dual and monocistronic reporter vectors. Results: With the dual reporter system, the disproportionate reduction of upstream reporter activity is not specific to AMD1 tail and occurs as long as the readthrough stop codon context is present at the end of the reporter's ORF. In a monocistronic vector without an IRES, the test sequences had distinct effects which were reflective of their properties e.g., AMD1 tail inhibitory effect. We further show by employing RT-qPCR that in the IRES vectors, the Fluc activity levels measured by the luciferase assay are an accurate proxy of RNA levels. Conclusions: While our findings provide little new information regarding the functional role of AMD1 tail, they raise caution for the use of viral IRES elements in expression vectors for studying mechanisms of mRNA translation. These findings may also be pertinent to the natural properties of readthrough permissive sequences and of IRES elements, though these require a separate investigation.
Collapse
Affiliation(s)
- Martina M. Yordanova
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - John F. Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Pavel V. Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russian Federation
| |
Collapse
|
47
|
Karki P, Carney TD, Maracci C, Yatsenko AS, Shcherbata HR, Rodnina MV. Tissue-specific regulation of translational readthrough tunes functions of the traffic jam transcription factor. Nucleic Acids Res 2021; 50:6001-6019. [PMID: 34897510 PMCID: PMC9226519 DOI: 10.1093/nar/gkab1189] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/05/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Translational readthrough (TR) occurs when the ribosome decodes a stop codon as a sense codon, resulting in two protein isoforms synthesized from the same mRNA. TR has been identified in several eukaryotic organisms; however, its biological significance and mechanism remain unclear. Here, we quantify TR of several candidate genes in Drosophila melanogaster and characterize the regulation of TR in the large Maf transcription factor Traffic jam (Tj). Using CRISPR/Cas9-generated mutant flies, we show that the TR-generated Tj isoform is expressed in a subset of neural cells of the central nervous system and is excluded from the somatic cells of gonads. Control of TR in Tj is critical for preservation of neuronal integrity and maintenance of reproductive health. The tissue-specific distribution of a release factor splice variant, eRF1H, plays a critical role in modulating differential TR of leaky stop codon contexts. Fine-tuning of gene regulatory functions of transcription factors by TR provides a potential mechanism for cell-specific regulation of gene expression.
Collapse
Affiliation(s)
- Prajwal Karki
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
| | - Travis D Carney
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Cristina Maracci
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
| | - Andriy S Yatsenko
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Halyna R Shcherbata
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
| |
Collapse
|
48
|
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] [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.
Collapse
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
| |
Collapse
|
49
|
Zinshteyn B, Sinha NK, Enam SU, Koleske B, Green R. Translational repression of NMD targets by GIGYF2 and EIF4E2. PLoS Genet 2021; 17:e1009813. [PMID: 34665823 PMCID: PMC8555832 DOI: 10.1371/journal.pgen.1009813] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 10/29/2021] [Accepted: 09/08/2021] [Indexed: 12/26/2022] Open
Abstract
Translation of messenger RNAs (mRNAs) with premature termination codons produces truncated proteins with potentially deleterious effects. This is prevented by nonsense-mediated mRNA decay (NMD) of these mRNAs. NMD is triggered by ribosomes terminating upstream of a splice site marked by an exon-junction complex (EJC), but also acts on many mRNAs lacking a splice junction after their termination codon. We developed a genome-wide CRISPR flow cytometry screen to identify regulators of mRNAs with premature termination codons in K562 cells. This screen recovered essentially all core NMD factors and suggested a role for EJC factors in degradation of PTCs without downstream splicing. Among the strongest hits were the translational repressors GIGYF2 and EIF4E2. GIGYF2 and EIF4E2 mediate translational repression but not mRNA decay of a subset of NMD targets and interact with NMD factors genetically and physically. Our results suggest a model wherein recognition of a stop codon as premature can lead to its translational repression through GIGYF2 and EIF4E2.
Collapse
Affiliation(s)
- Boris Zinshteyn
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Niladri K. Sinha
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Syed Usman Enam
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Benjamin Koleske
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Rachel Green
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- * E-mail:
| |
Collapse
|
50
|
Yordanova MM, Loughran G, Atkins JF, Baranov PV. Stop codon readthrough contexts influence reporter expression differentially depending on the presence of an IRES. Wellcome Open Res 2021; 5:221. [PMID: 35187266 PMCID: PMC8831848 DOI: 10.12688/wellcomeopenres.16231.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 08/23/2024] Open
Abstract
Background: Previously we reported the discovery of stop codon readthrough in AMD1 mRNA followed by ribosome stalling at the end of a conserved Open Reading Frame (ORF) that we termed AMD1. To explain the severe suppression of reporters fused to AMD1 tail we proposed a mechanism invoking ribosome queueing. To test this hypothesis, we placed the reporter stop codon in the context of readthrough permissive sequences in a dual reporter vector with downstream reporter expression driven by the EMCV IRES. In accordance with our hypothesis, we observed a striking disproportional reduction of upstream reporter activity in response to increased readthrough levels. Methods: We employ dual luciferase assays, western blotting and RT-qPCR to explore the effects of test sequences downstream to the reporter stop codon on its expression in dual and monocistronic reporter vectors. Results: With the dual reporter system, the disproportionate reduction of upstream reporter activity is not specific to AMD1 tail and occurs as long as the readthrough stop codon context is present at the end of the reporter's ORF. In a monocistronic vector without an IRES, the test sequences had distinct effects which were reflective of their properties e.g. AMD1 tail inhibitory effect. We further show with RT-qPCR that the EMCV IRES driven expression of a reporter is an accurate proxy of reporter RNA levels. Conclusions: While our findings provide little new information regarding the functional role of AMD1 tail, they raise caution for the use of viral IRES elements in expression vectors for studying mechanisms of mRNA translation. These findings may also be pertinent to the natural properties of read through permissive sequences and of IRES elements, though these require a separate investigation.
Collapse
Affiliation(s)
- Martina M. Yordanova
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - John F. Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Pavel V. Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russian Federation
| |
Collapse
|