1
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Sabath K, Nabih A, Arnold C, Moussa R, Domjan D, Zaugg JB, Jonas S. Basis of gene-specific transcription regulation by the Integrator complex. Mol Cell 2024:S1097-2765(24)00474-X. [PMID: 38906142 DOI: 10.1016/j.molcel.2024.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 03/04/2024] [Accepted: 05/29/2024] [Indexed: 06/23/2024]
Abstract
The Integrator complex attenuates gene expression via the premature termination of RNA polymerase II (RNAP2) at promoter-proximal pausing sites. It is required for stimulus response, cell differentiation, and neurodevelopment, but how gene-specific and adaptive regulation by Integrator is achieved remains unclear. Here, we identify two sites on human Integrator subunits 13/14 that serve as binding hubs for sequence-specific transcription factors (TFs) and other transcription effector complexes. When Integrator is attached to paused RNAP2, these hubs are positioned upstream of the transcription bubble, consistent with simultaneous TF-promoter tethering. The TFs co-localize with Integrator genome-wide, increase Integrator abundance on target genes, and co-regulate responsive transcriptional programs. For instance, sensory cilia formation induced by glucose starvation depends on Integrator-TF contacts. Our data suggest TF-mediated promoter recruitment of Integrator as a widespread mechanism for targeted transcription regulation.
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Affiliation(s)
- Kevin Sabath
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
| | - Amena Nabih
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Christian Arnold
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Rim Moussa
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - David Domjan
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Judith B Zaugg
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Stefanie Jonas
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
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2
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Jung S, Ko SH, Ahn N, Lee J, Park CH, Hwang J. Role of UPF1-LIN28A interaction during early differentiation of pluripotent stem cells. Nat Commun 2024; 15:158. [PMID: 38167913 PMCID: PMC10762078 DOI: 10.1038/s41467-023-44600-5] [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: 02/13/2023] [Accepted: 12/21/2023] [Indexed: 01/05/2024] Open
Abstract
UPF1 and LIN28A are RNA-binding proteins involved in post-transcriptional regulation and stem cell differentiation. Most studies on UPF1 and LIN28A have focused on the molecular mechanisms of differentiated cells and stem cell differentiation, respectively. We reveal that LIN28A directly interacts with UPF1 before UPF1-UPF2 complexing, thereby reducing UPF1 phosphorylation and inhibiting nonsense-mediated mRNA decay (NMD). We identify the interacting domains of UPF1 and LIN28A; moreover, we develop a peptide that impairs UPF1-LIN28A interaction and augments NMD efficiency. Transcriptome analysis of human pluripotent stem cells (hPSCs) confirms that the levels of NMD targets are significantly regulated by both UPF1 and LIN28A. Inhibiting the UPF1-LIN28A interaction using a CPP-conjugated peptide promotes spontaneous differentiation by repressing the pluripotency of hPSCs during proliferation. Furthermore, the UPF1-LIN28A interaction specifically regulates transcripts involved in ectodermal differentiation. Our study reveals that transcriptome regulation via the UPF1-LIN28A interaction in hPSCs determines cell fate.
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Affiliation(s)
- Seungwon Jung
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, Korea
| | - Seung Hwan Ko
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, Korea
| | - Narae Ahn
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, Korea
| | - Jinsam Lee
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, Korea
| | - Chang-Hwan Park
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, Korea.
| | - Jungwook Hwang
- Graduate School of Biomedical Science & Engineering, Hanyang University, Seoul, Korea.
- Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul, Korea.
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3
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Carrard J, Lejeune F. Nonsense-mediated mRNA decay, a simplified view of a complex mechanism. BMB Rep 2023; 56:625-632. [PMID: 38052423 PMCID: PMC10761751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/31/2023] [Accepted: 11/17/2023] [Indexed: 12/07/2023] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is both a quality control mechanism and a gene regulation pathway. It has been studied for more than 30 years, with an accumulation of many mechanistic details that have often led to debate and hence to different models of NMD activation, particularly in higher eukaryotes. Two models seem to be opposed, since the first requires intervention of the exon junction complex (EJC) to recruit NMD factors downstream of the premature termination codon (PTC), whereas the second involves an EJC-independent mechanism in which NMD factors concentrate in the 3'UTR to initiate NMD in the presence of a PTC. In this review we describe both models, giving recent molecular details and providing experimental arguments supporting one or the other model. In the end it is certainly possible to imagine that these two mechanisms co-exist, rather than viewing them as mutually exclusive. [BMB Reports 2023; 56(12): 625-632].
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Affiliation(s)
- Julie Carrard
- Univ. Lille, CNRS, Inserm, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, Lille F-59000, France
| | - Fabrice Lejeune
- Univ. Lille, CNRS, Inserm, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, Lille F-59000, France
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4
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Chang J, Shin MK, Park J, Hwang HJ, Locker N, Ahn J, Kim D, Baek D, Park Y, Lee Y, Boo SH, Kim HI, Kim YK. An interaction between eIF4A3 and eIF3g drives the internal initiation of translation. Nucleic Acids Res 2023; 51:10950-10969. [PMID: 37811880 PMCID: PMC10639049 DOI: 10.1093/nar/gkad763] [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: 11/04/2022] [Revised: 08/30/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
An RNA structure or modified RNA sequences can provide a platform for ribosome loading and internal translation initiation. The functional significance of internal translation has recently been highlighted by the discovery that a subset of circular RNAs (circRNAs) is internally translated. However, the molecular mechanisms underlying the internal initiation of translation in circRNAs remain unclear. Here, we identify eIF3g (a subunit of eIF3 complex) as a binding partner of eIF4A3, a core component of the exon-junction complex (EJC) that is deposited onto spliced mRNAs and plays multiple roles in the regulation of gene expression. The direct interaction between eIF4A3-eIF3g serves as a molecular linker between the eIF4A3 and eIF3 complex, thereby facilitating internal ribosomal entry. Protein synthesis from in vitro-synthesized circRNA demonstrates eIF4A3-driven internal translation, which relies on the eIF4A3-eIF3g interaction. Furthermore, our transcriptome-wide analysis shows that efficient polysomal association of endogenous circRNAs requires eIF4A3. Notably, a subset of endogenous circRNAs can express a full-length intact protein, such as β-catenin, in an eIF4A3-dependent manner. Collectively, our results expand the understanding of the protein-coding potential of the human transcriptome, including circRNAs.
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Affiliation(s)
- Jeeyoon Chang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Min-Kyung Shin
- Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Joori Park
- Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Hyun Jung Hwang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Nicolas Locker
- Department of Microbial and Cellular Sciences, University of Surrey, Guildford GU2 7HX, UK
| | - Junhak Ahn
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Doyeon Kim
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Daehyun Baek
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Yeonkyoung Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Yujin Lee
- Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Sung Ho Boo
- Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Hyeong-In Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Yoon Ki Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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5
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Klonowski J, Liang Q, Coban-Akdemir Z, Lo C, Kostka D. aenmd: annotating escape from nonsense-mediated decay for transcripts with protein-truncating variants. Bioinformatics 2023; 39:btad556. [PMID: 37688563 PMCID: PMC10534055 DOI: 10.1093/bioinformatics/btad556] [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: 03/17/2023] [Revised: 07/13/2023] [Accepted: 09/07/2023] [Indexed: 09/11/2023] Open
Abstract
SUMMARY DNA changes that cause premature termination codons (PTCs) represent a large fraction of clinically relevant pathogenic genomic variation. Typically, PTCs induce transcript degradation by nonsense-mediated mRNA decay (NMD) and render such changes loss-of-function alleles. However, certain PTC-containing transcripts escape NMD and can exert dominant-negative or gain-of-function (DN/GOF) effects. Therefore, systematic identification of human PTC-causing variants and their susceptibility to NMD contributes to the investigation of the role of DN/GOF alleles in human disease. Here we present aenmd, a software for annotating PTC-containing transcript-variant pairs for predicted escape from NMD. aenmd is user-friendly and self-contained. It offers functionality not currently available in other methods and is based on established and experimentally validated rules for NMD escape; the software is designed to work at scale, and to integrate seamlessly with existing analysis workflows. We applied aenmd to variants in the gnomAD, Clinvar, and GWAS catalog databases and report the prevalence of human PTC-causing variants in these databases, and the subset of these variants that could exert DN/GOF effects via NMD escape. AVAILABILITY AND IMPLEMENTATION aenmd is implemented in the R programming language. Code is available on GitHub as an R-package (github.com/kostkalab/aenmd.git), and as a containerized command-line interface (github.com/kostkalab/aenmd_cli.git).
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Affiliation(s)
- Jonathan Klonowski
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, United States
| | - Qianqian Liang
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, United States
| | - Zeynep Coban-Akdemir
- Department of Epidemiology, Human Genetics and Environmental Sciences, University of Texas School of Public Health, Houston, TX 77030, United States
| | - Cecilia Lo
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, United States
| | - Dennis Kostka
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, United States
- Department of Computational & Systems Biology and Center for Evolutionary Biology and Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260,United States
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6
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Leoni C, Bataclan M, Ito-Kureha T, Heissmeyer V, Monticelli S. The mRNA methyltransferase Mettl3 modulates cytokine mRNA stability and limits functional responses in mast cells. Nat Commun 2023; 14:3862. [PMID: 37386028 PMCID: PMC10310798 DOI: 10.1038/s41467-023-39614-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 06/16/2023] [Indexed: 07/01/2023] Open
Abstract
Mast cells are central players in allergy and asthma, and their dysregulated responses lead to reduced quality of life and life-threatening conditions such as anaphylaxis. The RNA modification N6-methyladenosine (m6A) has a prominent impact on immune cell functions, but its role in mast cells remains unexplored. Here, by optimizing tools to genetically manipulate primary mast cells, we reveal that the m6A mRNA methyltransferase complex modulates mast cell proliferation and survival. Depletion of the catalytic component Mettl3 exacerbates effector functions in response to IgE and antigen complexes, both in vitro and in vivo. Mechanistically, deletion of Mettl3 or Mettl14, another component of the methyltransferase complex, lead to the enhanced expression of inflammatory cytokines. By focusing on one of the most affected mRNAs, namely the one encoding the cytokine IL-13, we find that it is methylated in activated mast cells, and that Mettl3 affects its transcript stability in an enzymatic activity-dependent manner, requiring consensus m6A sites in the Il13 3'-untranslated region. Overall, we reveal that the m6A machinery is essential in mast cells to sustain growth and to restrain inflammatory responses.
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Affiliation(s)
- Cristina Leoni
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), 6500, Bellinzona, Switzerland.
| | - Marian Bataclan
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), 6500, Bellinzona, Switzerland
| | - Taku Ito-Kureha
- Institute for Immunology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, 82152, Planegg-Martinsried, Germany
| | - Vigo Heissmeyer
- Institute for Immunology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, 82152, Planegg-Martinsried, Germany
- Research Unit Molecular Immune Regulation, Helmholtz Zentrum München, 81377, Munich, Germany
| | - Silvia Monticelli
- Institute for Research in Biomedicine, Università della Svizzera italiana (USI), 6500, Bellinzona, Switzerland.
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7
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Sun L, Mailliot J, Schaffitzel C. Nonsense-Mediated mRNA Decay Factor Functions in Human Health and Disease. Biomedicines 2023; 11:722. [PMID: 36979701 PMCID: PMC10045457 DOI: 10.3390/biomedicines11030722] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a cellular surveillance mechanism that degrades mRNAs with a premature stop codon, avoiding the synthesis of C-terminally truncated proteins. In addition to faulty mRNAs, NMD recognises ~10% of endogenous transcripts in human cells and downregulates their expression. The up-frameshift proteins are core NMD factors and are conserved from yeast to human in structure and function. In mammals, NMD diversified into different pathways that target different mRNAs employing additional NMD factors. Here, we review our current understanding of molecular mechanisms and cellular roles of NMD pathways and the involvement of more specialised NMD factors. We describe the consequences of mutations in NMD factors leading to neurodevelopmental diseases, and the role of NMD in cancer. We highlight strategies of RNA viruses to evade recognition and decay by the NMD machinery.
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Affiliation(s)
- Lingling Sun
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Justine Mailliot
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Christiane Schaffitzel
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK
- Bristol Engineering Biology Centre BrisEngBio, 24 Tyndall Ave, Bristol BS8 1TQ, UK
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8
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Recoding of Nonsense Mutation as a Pharmacological Strategy. Biomedicines 2023; 11:biomedicines11030659. [PMID: 36979640 PMCID: PMC10044939 DOI: 10.3390/biomedicines11030659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Approximately 11% of genetic human diseases are caused by nonsense mutations that introduce a premature termination codon (PTC) into the coding sequence. The PTC results in the production of a potentially harmful shortened polypeptide and activation of a nonsense-mediated decay (NMD) pathway. The NMD pathway reduces the burden of unproductive protein synthesis by lowering the level of PTC mRNA. There is an endogenous rescue mechanism that produces a full-length protein from a PTC mRNA. Nonsense suppression therapies aim to increase readthrough, suppress NMD, or are a combination of both strategies. Therefore, treatment with translational readthrough-inducing drugs (TRIDs) and NMD inhibitors may increase the effectiveness of PTC suppression. Here we discuss the mechanism of PTC readthrough and the development of novel approaches to PTC suppression. We also discuss the toxicity and bioavailability of therapeutics used to stimulate PTC readthrough.
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9
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Leon KE, Khalid MM, Flynn RA, Fontaine KA, Nguyen TT, Kumar GR, Simoneau CR, Tomar S, Jimenez-Morales D, Dunlap M, Kaye J, Shah PS, Finkbeiner S, Krogan NJ, Bertozzi C, Carette JE, Ott M. Nuclear accumulation of host transcripts during Zika Virus Infection. PLoS Pathog 2023; 19:e1011070. [PMID: 36603024 PMCID: PMC9847913 DOI: 10.1371/journal.ppat.1011070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 01/18/2023] [Accepted: 12/17/2022] [Indexed: 01/06/2023] Open
Abstract
Zika virus (ZIKV) infects fetal neural progenitor cells (NPCs) causing severe neurodevelopmental disorders in utero. Multiple pathways involved in normal brain development are dysfunctional in infected NPCs but how ZIKV centrally reprograms these pathways remains unknown. Here we show that ZIKV infection disrupts subcellular partitioning of host transcripts critical for neurodevelopment in NPCs and functionally link this process to the up-frameshift protein 1 (UPF1). UPF1 is an RNA-binding protein known to regulate decay of cellular and viral RNAs and is less expressed in ZIKV-infected cells. Using infrared crosslinking immunoprecipitation and RNA sequencing (irCLIP-Seq), we show that a subset of mRNAs loses UPF1 binding in ZIKV-infected NPCs, consistent with UPF1's diminished expression. UPF1 target transcripts, however, are not altered in abundance but in subcellular localization, with mRNAs accumulating in the nucleus of infected or UPF1 knockdown cells. This leads to diminished protein expression of FREM2, a protein required for maintenance of NPC identity. Our results newly link UPF1 to the regulation of mRNA transport in NPCs, a process perturbed during ZIKV infection.
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Affiliation(s)
- Kristoffer E. Leon
- J. David Gladstone Institutes, San Francisco, California, United States of America
- Department of Medicine, University of California, San Francisco, California, United States of America
- Medical Scientist Training Program, University of California, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California, San Francisco, California, United States of America
| | - Mir M. Khalid
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Ryan A. Flynn
- Stem Cell Program, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Krystal A. Fontaine
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Thong T. Nguyen
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - G. Renuka Kumar
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Camille R. Simoneau
- J. David Gladstone Institutes, San Francisco, California, United States of America
- Department of Medicine, University of California, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California, San Francisco, California, United States of America
| | - Sakshi Tomar
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - David Jimenez-Morales
- J. David Gladstone Institutes, San Francisco, California, United States of America
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, California, United States of America
| | - Mariah Dunlap
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Julia Kaye
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Priya S. Shah
- Departments of Chemical Engineering and Microbiology and Molecular Genetics, University of California, Davis, California, United States of America
| | - Steven Finkbeiner
- J. David Gladstone Institutes, San Francisco, California, United States of America
- Center for Systems and Therapeutics and Taube/Koret Center for Neurodegenerative Disease Research, San Francisco, California, United States of America
- Departments of Neurology and Physiology, University of California, San Francisco, California, United States of America
| | - Nevan J. Krogan
- J. David Gladstone Institutes, San Francisco, California, United States of America
- Quantitative Biosciences Institute (QBI), University of California, San Francisco, California, United States of America
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California, United States of America
| | - Carolyn Bertozzi
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
| | - Jan E. Carette
- Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America
| | - Melanie Ott
- J. David Gladstone Institutes, San Francisco, California, United States of America
- Department of Medicine, University of California, San Francisco, California, United States of America
- Chan Zuckerberg Biohub, San Francisco, California, United States of America
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10
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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: 14] [Impact Index Per Article: 7.0] [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.
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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.
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11
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Guénolé A, Velilla F, Chartier A, Rich A, Carvunis AR, Sardet C, Simonelig M, Sobhian B. RNF219 regulates CCR4-NOT function in mRNA translation and deadenylation. Sci Rep 2022; 12:9288. [PMID: 35660762 PMCID: PMC9166816 DOI: 10.1038/s41598-022-13309-8] [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: 04/11/2019] [Accepted: 05/05/2022] [Indexed: 11/30/2022] Open
Abstract
Post-transcriptional regulatory mechanisms play a role in many biological contexts through the control of mRNA degradation, translation and localization. Here, we show that the RING finger protein RNF219 co-purifies with the CCR4-NOT complex, the major mRNA deadenylase in eukaryotes, which mediates translational repression in both a deadenylase activity-dependent and -independent manner. Strikingly, RNF219 both inhibits the deadenylase activity of CCR4-NOT and enhances its capacity to repress translation of a target mRNA. We propose that the interaction of RNF219 with the CCR4-NOT complex directs the translational repressive activity of CCR4-NOT to a deadenylation-independent mechanism.
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Affiliation(s)
- Aude Guénolé
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), 34298, Montpellier, France.
| | - Fabien Velilla
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), 34298, Montpellier, France
| | - Aymeric Chartier
- Institut de Génétique Humaine, CNRS, Université de Montpellier, 34396, Montpellier, France
| | - April Rich
- Department of Computational and Systems Biology, Pittsburgh Center for Evolutionary Biology and Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Anne-Ruxandra Carvunis
- Department of Computational and Systems Biology, Pittsburgh Center for Evolutionary Biology and Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Claude Sardet
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), 34298, Montpellier, France
| | - Martine Simonelig
- Institut de Génétique Humaine, CNRS, Université de Montpellier, 34396, Montpellier, France
| | - Bijan Sobhian
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), 34298, Montpellier, France. .,Institut de Génétique Humaine, CNRS, Université de Montpellier, 34396, Montpellier, France.
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12
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Schlautmann LP, Lackmann JW, Altmüller J, Dieterich C, Boehm V, Gehring NH. Exon junction complex-associated multi-adapter RNPS1 nucleates splicing regulatory complexes to maintain transcriptome surveillance. Nucleic Acids Res 2022; 50:5899-5918. [PMID: 35640609 PMCID: PMC9178013 DOI: 10.1093/nar/gkac428] [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: 08/20/2021] [Revised: 05/05/2022] [Accepted: 05/10/2022] [Indexed: 12/04/2022] Open
Abstract
The exon junction complex (EJC) is an RNA-binding multi-protein complex with critical functions in post-transcriptional gene regulation. It is deposited on the mRNA during splicing and regulates diverse processes including pre-mRNA splicing and nonsense-mediated mRNA decay (NMD) via various interacting proteins. The peripheral EJC-binding protein RNPS1 was reported to serve two insufficiently characterized functions: suppressing mis-splicing of cryptic splice sites and activating NMD in the cytoplasm. The analysis of transcriptome-wide effects of EJC and RNPS1 knockdowns in different human cell lines supports the conclusion that RNPS1 can moderately influence NMD activity, but is not a globally essential NMD factor. However, numerous aberrant splicing events strongly suggest that the main function of RNPS1 is splicing regulation. Rescue analyses revealed that the RRM and C-terminal domain of RNPS1 both contribute partially to regulate RNPS1-dependent splicing events. We defined the RNPS1 core interactome using complementary immunoprecipitations and proximity labeling, which identified interactions with splicing-regulatory factors that are dependent on the C-terminus or the RRM domain of RNPS1. Thus, RNPS1 emerges as a multifunctional splicing regulator that promotes correct and efficient splicing of different vulnerable splicing events via the formation of diverse splicing-promoting complexes.
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Affiliation(s)
- Lena P Schlautmann
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Jan-Wilm Lackmann
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Volker Boehm
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
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13
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Wallmeroth D, Lackmann JW, Kueckelmann S, Altmüller J, Dieterich C, Boehm V, Gehring NH. Human UPF3A and UPF3B enable fault-tolerant activation of nonsense-mediated mRNA decay. EMBO J 2022; 41:e109191. [PMID: 35451084 PMCID: PMC9108619 DOI: 10.15252/embj.2021109191] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 12/14/2022] Open
Abstract
The paralogous human proteins UPF3A and UPF3B are involved in recognizing mRNAs targeted by nonsense‐mediated mRNA decay (NMD). UPF3B has been demonstrated to support NMD, presumably by bridging an exon junction complex (EJC) to the NMD factor UPF2. The role of UPF3A has been described either as a weak NMD activator or an NMD inhibitor. Here, we present a comprehensive functional analysis of UPF3A and UPF3B in human cells using combinatory experimental approaches. Overexpression or knockout of UPF3A as well as knockout of UPF3B did not substantially change global NMD activity. In contrast, the co‐depletion of UPF3A and UPF3B resulted in a marked NMD inhibition and a transcriptome‐wide upregulation of NMD substrates, demonstrating a functional redundancy between both NMD factors. In rescue experiments, UPF2 or EJC binding‐deficient UPF3B largely retained NMD activity. However, combinations of different mutants, including deletion of the middle domain, showed additive or synergistic effects and therefore failed to maintain NMD. Collectively, UPF3A and UPF3B emerge as fault‐tolerant, functionally redundant NMD activators in human cells.
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Affiliation(s)
- Damaris Wallmeroth
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | | | - Sabrina Kueckelmann
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, Heidelberg University Hospital, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Volker Boehm
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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14
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Yi Z, Arvola RM, Myers S, Dilsavor CN, Abu Alhasan R, Carter BN, Patton RD, Bundschuh R, Singh G. Mammalian UPF3A and UPF3B can activate nonsense-mediated mRNA decay independently of their exon junction complex binding. EMBO J 2022; 41:e109202. [PMID: 35451102 PMCID: PMC9108626 DOI: 10.15252/embj.2021109202] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 03/21/2022] [Accepted: 03/31/2022] [Indexed: 12/30/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is governed by the three conserved factors-UPF1, UPF2, and UPF3. While all three are required for NMD in yeast, UPF3B is dispensable for NMD in mammals, and its paralog UPF3A is suggested to only weakly activate or even repress NMD due to its weaker binding to the exon junction complex (EJC). Here, we characterize the UPF3A/B-dependence of NMD in human cell lines deleted of one or both UPF3 paralogs. We show that in human colorectal cancer HCT116 cells, NMD can operate in a UPF3B-dependent and -independent manner. While UPF3A is almost dispensable for NMD in wild-type cells, it strongly activates NMD in cells lacking UPF3B. Notably, NMD remains partially active in cells lacking both UPF3 paralogs. Complementation studies in these cells show that EJC-binding domain of UPF3 paralogs is dispensable for NMD. Instead, the conserved "mid" domain of UPF3 paralogs is consequential for their NMD activity. Altogether, our results demonstrate that the mammalian UPF3 proteins play a more active role in NMD than simply bridging the EJC and the UPF complex.
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Affiliation(s)
- Zhongxia Yi
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - René M Arvola
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Sean Myers
- Department of Physics, The Ohio State University, Columbus, OH, USA
| | - Corinne N Dilsavor
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Rabab Abu Alhasan
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Bayley N Carter
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Robert D Patton
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Physics, The Ohio State University, Columbus, OH, USA
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Physics, The Ohio State University, Columbus, OH, USA.,Department of Chemistry and Biochemistry, The Ohio State University , Columbus, OH, USA.,Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA
| | - Guramrit Singh
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
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15
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Abstract
Nonsense-mediated mRNA decay (NMD) is an mRNA degradation pathway that eliminates transcripts containing premature termination codons (PTCs). Half-lives of the mRNAs containing PTCs demonstrate that a small percent escape surveillance and do not degrade. It is not known whether this escape represents variable mRNA degradation within cells or, alternatively cells within the population are resistant. Here we demonstrate a single-cell approach with a bi-directional reporter, which expresses two β-globin genes with or without a PTC in the same cell, to characterize the efficiency of NMD in individual cells. We found a broad range of NMD efficiency in the population; some cells degraded essentially all of the mRNAs, while others escaped NMD almost completely. Characterization of NMD efficiency together with NMD regulators in single cells showed cell-to-cell variability of NMD reflects the differential level of surveillance factors, SMG1 and phosphorylated UPF1. A single-cell fluorescent reporter system that enabled detection of NMD using flow cytometry revealed that this escape occurred either by translational readthrough at the PTC or by a failure of mRNA degradation after successful translation termination at the PTC.
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16
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Lu YY, Krebber H. Nuclear mRNA Quality Control and Cytoplasmic NMD Are Linked by the Guard Proteins Gbp2 and Hrb1. Int J Mol Sci 2021; 22:ijms222011275. [PMID: 34681934 PMCID: PMC8541090 DOI: 10.3390/ijms222011275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 12/23/2022] Open
Abstract
Pre-mRNA splicing is critical for cells, as defects in this process can lead to altered open reading frames and defective proteins, potentially causing neurodegenerative diseases and cancer. Introns are removed in the nucleus and splicing is documented by the addition of exon-junction-complexes (EJCs) at exon-exon boundaries. This “memory” of splicing events is important for the ribosome, which translates the RNAs in the cytoplasm. In case a stop codon was detected before an EJC, translation is blocked and the RNA is eliminated by the nonsense-mediated decay (NMD). In the model organism Saccharomyces cerevisiae, two guard proteins, Gbp2 and Hrb1, have been identified as nuclear quality control factors for splicing. In their absence, intron-containing mRNAs leak into the cytoplasm. Their presence retains transcripts until the process is completed and they release the mRNAs by recruitment of the export factor Mex67. On transcripts that experience splicing problems, these guard proteins recruit the nuclear RNA degradation machinery. Interestingly, they continue their quality control function on exported transcripts. They support NMD by inhibiting translation and recruiting the cytoplasmic degradation factors. In this way, they link the nuclear and cytoplasmic quality control systems. These discoveries are also intriguing for humans, as homologues of these guard proteins are present also in multicellular organisms. Here, we provide an overview of the quality control mechanisms of pre-mRNA splicing, and present Gbp2 and Hrb1, as well as their human counterparts, as important players in these pathways.
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17
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Machado de Amorim A, Chakrabarti S. Assembly of multicomponent machines in RNA metabolism: A common theme in mRNA decay pathways. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1684. [PMID: 34351053 DOI: 10.1002/wrna.1684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/05/2022]
Abstract
Multicomponent protein-RNA complexes comprising a ribonuclease and partner RNA helicase facilitate the turnover of mRNA in all domains of life. While these higher-order complexes provide an effective means of physically and functionally coupling the processes of RNA remodeling and decay, most ribonucleases and RNA helicases do not exhibit sequence specificity in RNA binding. This raises the question as to how these assemblies select substrates for processing and how the activities are orchestrated at the precise moment to ensure efficient decay. The answers to these apparent puzzles lie in the auxiliary components of the assemblies that might relay decay-triggering signals. Given their function within the assemblies, these components may be viewed as "sensors." The functions and mechanisms of action of the sensor components in various degradation complexes in bacteria and eukaryotes are highlighted here to discuss their roles in RNA decay processes. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.
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Affiliation(s)
| | - Sutapa Chakrabarti
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
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18
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Cheruiyot A, Li S, Nonavinkere Srivatsan S, Ahmed T, Chen Y, Lemacon DS, Li Y, Yang Z, Wadugu BA, Warner WA, Pruett-Miller SM, Obeng EA, Link DC, He D, Xiao F, Wang X, Bailis JM, Walter MJ, You Z. Nonsense-Mediated RNA Decay Is a Unique Vulnerability of Cancer Cells Harboring SF3B1 or U2AF1 Mutations. Cancer Res 2021; 81:4499-4513. [PMID: 34215620 DOI: 10.1158/0008-5472.can-20-4016] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 05/26/2021] [Accepted: 06/30/2021] [Indexed: 11/16/2022]
Abstract
Nonsense-mediated RNA decay (NMD) is recognized as an RNA surveillance pathway that targets aberrant mRNAs with premature translation termination codons (PTC) for degradation, however, its molecular mechanisms and roles in health and disease remain incompletely understood. In this study, we developed a novel reporter system to accurately measure NMD activity in individual cells. A genome-wide CRISPR-Cas9 knockout screen using this reporter system identified novel NMD-promoting factors, including multiple components of the SF3B complex and other U2 spliceosome factors. Interestingly, cells with mutations in the spliceosome genes SF3B1 and U2AF1, which are commonly found in myelodysplastic syndrome (MDS) and cancers, have overall attenuated NMD activity. Compared with wild-type (WT) cells, SF3B1- and U2AF1-mutant cells were more sensitive to NMD inhibition, a phenotype that is accompanied by elevated DNA replication obstruction, DNA damage, and chromosomal instability. Remarkably, the sensitivity of spliceosome mutant cells to NMD inhibition was rescued by overexpression of RNase H1, which removes R-loops in the genome. Together, these findings shed new light on the functional interplay between NMD and RNA splicing and suggest a novel synthetic lethal strategy for the treatment of MDS and cancers with spliceosome mutations. SIGNIFICANCE: This study has developed a novel NMD reporter system and identified a potential therapeutic approach of targeting the NMD pathway to treat cancer with spliceosome gene mutations.
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Affiliation(s)
- Abigael Cheruiyot
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Shan Li
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Sridhar Nonavinkere Srivatsan
- Division of Hematology and Oncology, Department of Medicine, School of Medicine, Washington University School in St. Louis, St. Louis, Missouri
| | - Tanzir Ahmed
- Division of Hematology and Oncology, Department of Medicine, School of Medicine, Washington University School in St. Louis, St. Louis, Missouri
| | - Yuhao Chen
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Delphine S Lemacon
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Ying Li
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri.,Clinical Biobank, The Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Zheng Yang
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri.,Department of Urology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, China
| | - Brian A Wadugu
- Division of Hematology and Oncology, Department of Medicine, School of Medicine, Washington University School in St. Louis, St. Louis, Missouri
| | - Wayne A Warner
- Division of Hematology and Oncology, Department of Medicine, School of Medicine, Washington University School in St. Louis, St. Louis, Missouri
| | - Shondra M Pruett-Miller
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Esther A Obeng
- Molecular Oncology Division, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Daniel C Link
- Division of Hematology and Oncology, Department of Medicine, School of Medicine, Washington University School in St. Louis, St. Louis, Missouri
| | - Dalin He
- Department of Urology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, China
| | - Fei Xiao
- Clinical Biobank, The Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P.R. China
| | - Xiaowei Wang
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | | | - Matthew J Walter
- Division of Hematology and Oncology, Department of Medicine, School of Medicine, Washington University School in St. Louis, St. Louis, Missouri
| | - Zhongsheng You
- Department of Cell Biology and Physiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri.
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19
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Mishima Y, Inoue K. Tethered Function Assay to Study RNA-Regulatory Proteins in Zebrafish Embryos. Methods Mol Biol 2021; 2218:347-354. [PMID: 33606244 DOI: 10.1007/978-1-0716-0970-5_27] [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] [Indexed: 06/12/2023]
Abstract
Many proteins are assumed to mediate post-transcriptional regulation of mRNAs. However, the lack of information about their target mRNAs and functional domains hampers the detailed analysis of their molecular function. Here we describe a method to analyze the post-transcriptional effects of proteins of interest by artificially tethering the protein to a reporter mRNA in zebrafish embryos.
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Affiliation(s)
- Yuichiro Mishima
- Department of Frontier Life Sciences, Faculty of Lifesciences, Kyoto Sangyo University, Kyoto, Japan.
| | - Kunio Inoue
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, Japan
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20
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Deka B, Chandra P, Singh KK. Functional roles of human Up-frameshift suppressor 3 (UPF3) proteins: From nonsense-mediated mRNA decay to neurodevelopmental disorders. Biochimie 2020; 180:10-22. [PMID: 33132159 DOI: 10.1016/j.biochi.2020.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/03/2020] [Accepted: 10/22/2020] [Indexed: 12/26/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is a post-transcriptional quality control mechanism that eradicates aberrant transcripts from cells. Aberrant transcripts are recognized by translating ribosomes, eRFs, and trans-acting NMD factors leading to their degradation. The trans-factors are conserved among eukaryotes and consist of UPF1, UPF2, and UPF3 proteins. Intriguingly, in humans, UPF3 exists as paralog proteins, UPF3A, and UPF3B. While UPF3 paralogs are traditionally known to be involved in the NMD pathway, there is a growing consensus that there are other critical cellular functions beyond quality control that are dictated by the UPF3 proteins. This review presents the current knowledge on the biochemical functions of UPF3 paralogs in diverse cellular processes, including NMD, translation, and genetic compensation response. We also discuss the contribution of the UPF3 paralogs in development and function of the central nervous system and germ cells. Furthermore, significant advances in the past decade have provided new perspectives on the implications of UPF3 paralogs in neurodevelopmental diseases. In this regard, genome- and transcriptome-wide sequencing analysis of patient samples revealed that loss of UPF3B is associated with brain disorders such as intellectual disability, autism, attention deficit hyperactivity disorder, and schizophrenia. Therefore, we further aim to provide an insight into the brain diseases associated with loss-of-function mutations of UPF3B.
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Affiliation(s)
- Bhagyashree Deka
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
| | - Pratap Chandra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
| | - Kusum Kumari Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
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21
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The Branched Nature of the Nonsense-Mediated mRNA Decay Pathway. Trends Genet 2020; 37:143-159. [PMID: 33008628 DOI: 10.1016/j.tig.2020.08.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is a conserved translation-coupled quality control mechanism in all eukaryotes that regulates the expression of a significant fraction of both the aberrant and normal transcriptomes. In vertebrates, NMD has become an essential process owing to expansion of the diversity of NMD-regulated transcripts, particularly during various developmental processes. Surprisingly, however, some core NMD factors that are essential for NMD in simpler organisms appear to be dispensable for vertebrate NMD. At the same time, numerous NMD enhancers and suppressors have been identified in multicellular organisms including vertebrates. Collectively, the available data suggest that vertebrate NMD is a complex, branched pathway wherein individual branches regulate specific mRNA subsets to fulfill distinct physiological functions.
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22
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Michalak M, Katzenmaier EM, Roeckel N, Woerner SM, Fuchs V, Warnken U, Yuan YP, Bork P, Neu-Yilik G, Kulozik A, von Knebel Doeberitz M, Kloor M, Kopitz J, Gebert J. (Phospho)proteomic Profiling of Microsatellite Unstable CRC Cells Reveals Alterations in Nuclear Signaling and Cholesterol Metabolism Caused by Frameshift Mutation of NMD Regulator UPF3A. Int J Mol Sci 2020; 21:ijms21155234. [PMID: 32718059 PMCID: PMC7432364 DOI: 10.3390/ijms21155234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/13/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022] Open
Abstract
DNA mismatch repair-deficient colorectal cancers (CRCs) accumulate numerous frameshift mutations at repetitive sequences recognized as microsatellite instability (MSI). When coding mononucleotide repeats (cMNRs) are affected, tumors accumulate frameshift mutations and premature termination codons (PTC) potentially leading to truncated proteins. Nonsense-mediated RNA decay (NMD) can degrade PTC-containing transcripts and protect from such faulty proteins. As it also regulates normal transcripts and cellular physiology, we tested whether NMD genes themselves are targets of MSI frameshift mutations. A high frequency of cMNR frameshift mutations in the UPF3A gene was found in MSI CRC cell lines (67.7%), MSI colorectal adenomas (55%) and carcinomas (63%). In normal colonic crypts, UPF3A expression was restricted to single chromogranin A-positive cells. SILAC-based proteomic analysis of KM12 CRC cells revealed UPF3A-dependent down-regulation of several enzymes involved in cholesterol biosynthesis. Furthermore, reconstituted UPF3A expression caused alterations of 85 phosphosites in 52 phosphoproteins. Most of them (38/52, 73%) reside in nuclear phosphoproteins involved in regulation of gene expression and RNA splicing. Since UPF3A mutations can modulate the (phospho)proteomic signature and expression of enzymes involved in cholesterol metabolism in CRC cells, UPF3A may influence other processes than NMD and loss of UPF3A expression might provide a growth advantage to MSI CRC cells.
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Affiliation(s)
- Malwina Michalak
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Department of Pediatric Oncology, Hematology and Immunology, Children’s Hospital, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Eva-Maria Katzenmaier
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
| | - Nina Roeckel
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
| | - Stefan M. Woerner
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Department of Internal Medicine I, Endocrinology and Metabolism, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Vera Fuchs
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
| | - Uwe Warnken
- Clinical Cooperation Unit Neurooncology, DKFZ (German Cancer Research Center), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany;
| | - Yan P. Yuan
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany;
| | - Peer Bork
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany;
- Max-Delbrück-Centre for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Gabriele Neu-Yilik
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Department of Pediatric Oncology, Hematology and Immunology, Children’s Hospital, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Andreas Kulozik
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Department of Pediatric Oncology, Hematology and Immunology, Children’s Hospital, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Magnus von Knebel Doeberitz
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Clinical Cooperation Unit Applied Tumor Biology, DKFZ (German Cancer Research Center) Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Matthias Kloor
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Clinical Cooperation Unit Applied Tumor Biology, DKFZ (German Cancer Research Center) Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Jürgen Kopitz
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Clinical Cooperation Unit Applied Tumor Biology, DKFZ (German Cancer Research Center) Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Johannes Gebert
- Department of Applied Tumor Biology, Institute of Pathology, Heidelberg University Hospital, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany; (M.M.); (E.-M.K.); (N.R.); (V.F.); (M.v.K.D.); (M.K.); (J.K.)
- Molecular Medicine Partnership Unit, Medical Faculty of the University of Heidelberg and European Molecular Biology Laboratory, 69120 Heidelberg, Germany; (S.M.W.); (P.B.); (G.N.-Y.); (A.K.)
- Clinical Cooperation Unit Applied Tumor Biology, DKFZ (German Cancer Research Center) Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
- Correspondence: ; Tel.: +49-6221-564223
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23
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Sabath K, Stäubli ML, Marti S, Leitner A, Moes M, Jonas S. INTS10-INTS13-INTS14 form a functional module of Integrator that binds nucleic acids and the cleavage module. Nat Commun 2020; 11:3422. [PMID: 32647223 PMCID: PMC7347597 DOI: 10.1038/s41467-020-17232-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/18/2020] [Indexed: 11/18/2022] Open
Abstract
The Integrator complex processes 3′-ends of spliceosomal small nuclear RNAs (snRNAs). Furthermore, it regulates transcription of protein coding genes by terminating transcription after unstable pausing. The molecular basis for Integrator’s functions remains obscure. Here, we show that INTS10, Asunder/INTS13 and INTS14 form a separable, functional Integrator module. The structure of INTS13-INTS14 reveals a strongly entwined complex with a unique chain interlink. Unexpected structural homology to the Ku70-Ku80 DNA repair complex suggests nucleic acid affinity. Indeed, the module displays affinity for DNA and RNA but prefers RNA hairpins. While the module plays an accessory role in snRNA maturation, it has a stronger influence on transcription termination after pausing. Asunder/INTS13 directly binds Integrator’s cleavage module via a conserved C-terminal motif that is involved in snRNA processing and required for spermatogenesis. Collectively, our data establish INTS10-INTS13-INTS14 as a nucleic acid-binding module and suggest that it brings cleavage module and target transcripts into proximity. The Integrator complex (INT) is responsible for the 3′-end processing of several classes of non-coding RNAs. Here the authors show that the INTS10-INTS13-INTS14 complex forms a distinct submodule of INT and suggest it facilitates RNA substrate targeting.
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Affiliation(s)
- Kevin Sabath
- Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, CH-8093, Zurich, Switzerland
| | - Melanie L Stäubli
- Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, CH-8093, Zurich, Switzerland
| | - Sabrina Marti
- Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, CH-8093, Zurich, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Murielle Moes
- Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, CH-8093, Zurich, Switzerland
| | - Stefanie Jonas
- Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, CH-8093, Zurich, Switzerland.
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24
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Boussion S, Escande F, Jourdain AS, Smol T, Brunelle P, Duhamel C, Alembik Y, Attié-Bitach T, Baujat G, Bazin A, Bonnière M, Carassou P, Carles D, Devisme L, Goizet C, Goldenberg A, Grotto S, Guichet A, Jouk PS, Loeuillet L, Mechler C, Michot C, Pelluard F, Putoux A, Whalen S, Ghoumid J, Manouvrier-Hanu S, Petit F. TAR syndrome: Clinical and molecular characterization of a cohort of 26 patients and description of novel noncoding variants of RBM8A. Hum Mutat 2020; 41:1220-1225. [PMID: 32227665 DOI: 10.1002/humu.24021] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/18/2020] [Accepted: 03/22/2020] [Indexed: 11/07/2022]
Abstract
Thrombocytopenia-absent radius (TAR) syndrome is characterized by radial defect and neonatal thrombocytopenia. It is caused by biallelic variants of RBM8A gene (1q21.1) with the association of a null allele and a hypomorphic noncoding variant. RBM8A encodes Y14, a core protein of the exon junction complex involved in messenger RNA maturation. To date, only two hypomorphic variants have been identified. We report on a cohort of 26 patients affected with TAR syndrome and carrying biallelic variants in RBM8A. Half patients carried a 1q21.1 deletion and one of the two known hypomorphic variants. Four novel noncoding variants of RBM8A were identified in the remaining patients. We developed experimental models enabling their functional characterization in vitro. Two variants, located respectively in the 5'-untranslated region (5'-UTR) and 3'-UTR regions, are responsible for a diminished expression whereas two intronic variants alter splicing. Our results bring new insights into the molecular knowledge of TAR syndrome and enabled us to propose genetic counseling for patients' families.
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Affiliation(s)
- Simon Boussion
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
| | - Fabienne Escande
- EA7364-RADEME, Lille University, Lille, France
- Biochemistry and Molecular Oncology Laboratory, CHU Lille, Lille, France
| | - Anne-Sophie Jourdain
- EA7364-RADEME, Lille University, Lille, France
- Biochemistry and Molecular Oncology Laboratory, CHU Lille, Lille, France
| | - Thomas Smol
- EA7364-RADEME, Lille University, Lille, France
- Medical Genetics Department, CHU Lille, Lille, France
| | - Perrine Brunelle
- EA7364-RADEME, Lille University, Lille, France
- Biochemistry and Molecular Oncology Laboratory, CHU Lille, Lille, France
| | | | - Yves Alembik
- Medical Genetics Department, CHU Strasbourg, Strasbourg, France
| | - Tania Attié-Bitach
- Histology, Embryology and Cytogenetics Department, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Geneviève Baujat
- Clinical Genetics Department, Necker-Enfants Malades Hospital, AP-HP, INSERM UMR, IMAGINE Institute, Paris, France
| | - Anne Bazin
- Antenatal Diagnosis Department, René Dubois Hospital, Pontoise, France
| | - Maryse Bonnière
- Histology, Embryology and Cytogenetics Department, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | | | | | - Louise Devisme
- EA7364-RADEME, Lille University, Lille, France
- Anatomo-Pathology Institute, CHU Lille, Lille, France
| | - Cyril Goizet
- Medical Genetics Department, CHU Bordeaux, MRGM Laboratory, INSERM, Bordeaux University, Bordeaux, France
| | - Alice Goldenberg
- Genetics Department, Reference Center for Developmental Anomalies, CHU Rouen, Rouen, France
| | - Sarah Grotto
- Genetics Department, Robert Debré Hospital, AP-HP, Paris, France
| | | | | | | | - Charlotte Mechler
- Foetopathology Department, Robert Debré Hospital, AP-HP, Paris, France
| | - Caroline Michot
- Clinical Genetics Department, Necker-Enfants Malades Hospital, AP-HP, INSERM UMR, IMAGINE Institute, Paris, France
| | - Fanny Pelluard
- INSERM U1053-UMR BaRITOn, Foetopathology Department, Pellegrin Hospital, CHU Bordeaux, Bordeaux, France
| | - Audrey Putoux
- Genetics Department, Hospices Civils de Lyon, Lyon, France
- GENDEV Team, CRNL, INSERM U1028, CNRS UMR 5292, UCBL1, Lyon, France
| | - Sandra Whalen
- Clinical Genetics, Reference Center for Developmental Anomalies, Armand Trousseau Hospital, AP-HP, Paris, France
| | - Jamal Ghoumid
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
| | - Sylvie Manouvrier-Hanu
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
| | - Florence Petit
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
- EA7364-RADEME, Lille University, Lille, France
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25
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Nonsense-Mediated mRNA Decay: Pathologies and the Potential for Novel Therapeutics. Cancers (Basel) 2020; 12:cancers12030765. [PMID: 32213869 PMCID: PMC7140085 DOI: 10.3390/cancers12030765] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/19/2020] [Accepted: 03/19/2020] [Indexed: 12/22/2022] Open
Abstract
Nonsense-mediated messenger RNA (mRNA) decay (NMD) is a surveillance pathway used by cells to control the quality mRNAs and to fine-tune transcript abundance. NMD plays an important role in cell cycle regulation, cell viability, DNA damage response, while also serving as a barrier to virus infection. Disturbance of this control mechanism caused by genetic mutations or dys-regulation of the NMD pathway can lead to pathologies, including neurological disorders, immune diseases and cancers. The role of NMD in cancer development is complex, acting as both a promoter and a barrier to tumour progression. Cancer cells can exploit NMD for the downregulation of key tumour suppressor genes, or tumours adjust NMD activity to adapt to an aggressive immune microenvironment. The latter case might provide an avenue for therapeutic intervention as NMD inhibition has been shown to lead to the production of neoantigens that stimulate an immune system attack on tumours. For this reason, understanding the biology and co-option pathways of NMD is important for the development of novel therapeutic agents. Inhibitors, whose design can make use of the many structures available for NMD study, will play a crucial role in characterizing and providing diverse therapeutic options for this pathway in cancer and other diseases.
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26
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Kurosaki T, Popp MW, Maquat LE. Quality and quantity control of gene expression by nonsense-mediated mRNA decay. Nat Rev Mol Cell Biol 2020; 20:406-420. [PMID: 30992545 DOI: 10.1038/s41580-019-0126-2] [Citation(s) in RCA: 421] [Impact Index Per Article: 105.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonsense-mediated mRNA decay (NMD) is one of the best characterized and most evolutionarily conserved cellular quality control mechanisms. Although NMD was first found to target one-third of mutated, disease-causing mRNAs, it is now known to also target ~10% of unmutated mammalian mRNAs to facilitate appropriate cellular responses - adaptation, differentiation or death - to environmental changes. Mutations in NMD genes in humans are associated with intellectual disability and cancer. In this Review, we discuss how NMD serves multiple purposes in human cells by degrading both mutated mRNAs to protect the integrity of the transcriptome and normal mRNAs to control the quantities of unmutated transcripts.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.,Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Maximilian W Popp
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.,Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA. .,Center for RNA Biology, University of Rochester, Rochester, NY, USA.
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27
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Rahman MA, Lin KT, Bradley RK, Abdel-Wahab O, Krainer AR. Recurrent SRSF2 mutations in MDS affect both splicing and NMD. Genes Dev 2020; 34:413-427. [PMID: 32001512 PMCID: PMC7050488 DOI: 10.1101/gad.332270.119] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/20/2019] [Indexed: 12/23/2022]
Abstract
Oncogenic mutations in the RNA splicing factors SRSF2, SF3B1, and U2AF1 are the most frequent class of mutations in myelodysplastic syndromes and are also common in clonal hematopoiesis, acute myeloid leukemia, chronic lymphocytic leukemia, and a variety of solid tumors. They cause genome-wide splicing alterations that affect important regulators of hematopoiesis. Several mRNA isoforms promoted by the various splicing factor mutants comprise a premature termination codon (PTC) and are therefore potential targets of nonsense-mediated mRNA decay (NMD). In light of the mechanistic relationship between splicing and NMD, we sought evidence for a specific role of mutant SRSF2 in NMD. We show that SRSF2 Pro95 hot spot mutations elicit enhanced mRNA decay, which is dependent on sequence-specific RNA binding and splicing. SRSF2 mutants enhance the deposition of exon junction complexes (EJCs) downstream from the PTC through RNA-mediated molecular interactions. This architecture then favors the association of key NMD factors to elicit mRNA decay. Gene-specific blocking of EJC deposition by antisense oligonucleotides circumvents aberrant NMD promoted by mutant SRSF2, restoring the expression of PTC-containing transcript. Our study uncovered critical effects of SRSF2 mutants in hematologic malignancies, reflecting the regulation at multiple levels of RNA metabolism, from splicing to decay.
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Affiliation(s)
| | - Kuan-Ting Lin
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.,Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Omar Abdel-Wahab
- Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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28
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Bartkowska K, Tepper B, Turlejski K, Djavadian RL. Roles of the exon junction complex components in the central nervous system: a mini review. Rev Neurosci 2019; 29:817-824. [PMID: 29791316 DOI: 10.1515/revneuro-2017-0113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 03/22/2018] [Indexed: 01/02/2023]
Abstract
The exon junction complex (EJC) consists of four core proteins: Magoh, RNA-binding motif 8A (Rbm8a, also known as Y14), eukaryotic initiation factor 4A3 (eIF4A3, also known as DDX48), and metastatic lymph node 51 (MLN51, also known as Casc3 or Barentsz), which are involved in the regulation of many processes occurring between gene transcription and protein translation. Its main role is to assemble into spliceosomes at the exon-exon junction of mRNA during splicing. It is, therefore, a range of functions concerning post-splicing events such as mRNA translocation, translation, and nonsense-mediated mRNA decay (NMD). Apart from this, proteins of the EJC control the splicing of specific pre-mRNAs, for example, splicing of the mapk transcript. Recent studies support essential functions of EJC proteins in oocytes and, after fertilization, in all stages of zygote development, as well as the growth of the embryo, including the development of the nervous system. During the development of the central nervous system (CNS), the EJC controls mitosis, regulating both symmetric and asymmetric cell divisions. Reduced levels of EJC components cause microcephaly. In the adult brain, Y14 and eIF4A3 appear to be involved in synaptic plasticity and in learning and memory. In this review, we focus on the involvement of EJC components in brain development and its functioning under normal conditions.
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Affiliation(s)
- Katarzyna Bartkowska
- Department of Molecular and Cellular Biology, Nencki Institute of Experimental Biology Polish Academy of Sciences, Warsaw, Poland
| | - Beata Tepper
- Department of Molecular and Cellular Biology, Nencki Institute of Experimental Biology Polish Academy of Sciences, Warsaw, Poland
| | - Kris Turlejski
- Faculty of Biology and Environmental Sciences, Cardinal Stefan Wyszynski University, Warsaw, Poland
| | - Ruzanna L Djavadian
- Department of Molecular and Cellular Biology, Nencki Institute of Experimental Biology Polish Academy of Sciences, Warsaw 02-093, Poland
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29
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Amaya Ramirez CC, Hubbe P, Mandel N, Béthune J. 4EHP-independent repression of endogenous mRNAs by the RNA-binding protein GIGYF2. Nucleic Acids Res 2019; 46:5792-5808. [PMID: 29554310 PMCID: PMC6009589 DOI: 10.1093/nar/gky198] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 03/07/2018] [Indexed: 11/12/2022] Open
Abstract
Initially identified as a factor involved in tyrosine kinase receptor signaling, Grb10-interacting GYF protein 2 (GIGYF2) has later been shown to interact with the 5′ cap-binding protein 4EHP as part of a translation repression complex, and to mediate post-transcriptional repression of tethered reporter mRNAs. A current model proposes that GIGYF2 is indirectly recruited to mRNAs by specific RNA-binding proteins (RBPs) leading to translation repression through its association with 4EHP. Accordingly, we recently observed that GIGYF2 also interacts with the miRNA-induced silencing complex and probably modulates its translation repression activity. Here we have further investigated how GIGYF2 represses mRNA function. In a tethering reporter assay, we identify three independent domains of GIGYF2 with repressive activity. In this assay, GIGYF2-mediated repression is independent of 4EHP but largely dependent on the CCR4/NOT complex that GIGYF2 recruits through multiple interfaces. Importantly, we show that GIGYF2 is an RBP and identify for the first time endogenous mRNA targets that recapitulate 4EHP-independent repression. Altogether, we propose that GIGYF2 has two distinct mechanisms of repression: one depends on 4EHP binding and mainly affects translation; the other is 4EHP-independent and involves the CCR4/NOT complex and its deadenylation activity.
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Affiliation(s)
- Cinthia C Amaya Ramirez
- CellNetworks Junior Research Group Posttranscriptional Regulation of mRNA Expression and Localization, Heidelberg University, D-69120 Heidelberg, Germany.,Biochemistry Center, Heidelberg University, D-69120 Heidelberg, Germany
| | - Petra Hubbe
- CellNetworks Junior Research Group Posttranscriptional Regulation of mRNA Expression and Localization, Heidelberg University, D-69120 Heidelberg, Germany.,Biochemistry Center, Heidelberg University, D-69120 Heidelberg, Germany
| | - Nicolas Mandel
- CellNetworks Junior Research Group Posttranscriptional Regulation of mRNA Expression and Localization, Heidelberg University, D-69120 Heidelberg, Germany.,Biochemistry Center, Heidelberg University, D-69120 Heidelberg, Germany
| | - Julien Béthune
- CellNetworks Junior Research Group Posttranscriptional Regulation of mRNA Expression and Localization, Heidelberg University, D-69120 Heidelberg, Germany.,Biochemistry Center, Heidelberg University, D-69120 Heidelberg, Germany
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30
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Lloyd JPB, Lang D, Zimmer AD, Causier B, Reski R, Davies B. The loss of SMG1 causes defects in quality control pathways in Physcomitrella patens. Nucleic Acids Res 2019; 46:5822-5836. [PMID: 29596649 PMCID: PMC6009662 DOI: 10.1093/nar/gky225] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/16/2018] [Indexed: 12/16/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is important for RNA quality control and gene regulation in eukaryotes. NMD targets aberrant transcripts for decay and also directly influences the abundance of non-aberrant transcripts. In animals, the SMG1 kinase plays an essential role in NMD by phosphorylating the core NMD factor UPF1. Despite SMG1 being ubiquitous throughout the plant kingdom, little is known about its function, probably because SMG1 is atypically absent from the genome of the model plant, Arabidopsis thaliana. By combining our previously established SMG1 knockout in moss with transcriptome-wide analysis, we reveal the range of processes involving SMG1 in plants. Machine learning assisted analysis suggests that 32% of multi-isoform genes produce NMD-targeted transcripts and that splice junctions downstream of a stop codon act as the major determinant of NMD targeting. Furthermore, we suggest that SMG1 is involved in other quality control pathways, affecting DNA repair and the unfolded protein response, in addition to its role in mRNA quality control. Consistent with this, smg1 plants have increased susceptibility to DNA damage, but increased tolerance to unfolded protein inducing agents. The potential involvement of SMG1 in RNA, DNA and protein quality control has major implications for the study of these processes in plants.
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Affiliation(s)
- James P B Lloyd
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, UK
| | - Daniel Lang
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Andreas D Zimmer
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Barry Causier
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, UK
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.,BIOSS - Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Brendan Davies
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, UK
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31
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Kishor A, Fritz SE, Hogg JR. Nonsense-mediated mRNA decay: The challenge of telling right from wrong in a complex transcriptome. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1548. [PMID: 31131562 DOI: 10.1002/wrna.1548] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/01/2019] [Accepted: 05/07/2019] [Indexed: 12/18/2022]
Abstract
The nonsense-mediated mRNA decay pathway selects and degrades its targets using a dense network of RNA-protein and protein-protein interactions. Together, these interactions allow the pathway to collect copious information about the translating mRNA, including translation termination status, splice junction positions, mRNP composition, and 3'UTR length and structure. The core NMD machinery, centered on the RNA helicase UPF1, integrates this information to determine the efficiency of decay. A picture of NMD is emerging in which many factors contribute to the dynamics of decay complex assembly and disassembly, thereby influencing the probability of decay. The ability of the NMD pathway to recognize mRNP features of diverse potential substrates allows it to simultaneously perform quality control and regulatory functions. In vertebrates, increased transcriptome complexity requires balance between these two functions since high NMD efficiency is desirable for maintenance of quality control fidelity but may impair expression of normal mRNAs. NMD has adapted to this challenge by employing mechanisms to enhance identification of certain potential substrates, while using sequence-specific RNA-binding proteins to shield others from detection. These elaborations on the conserved NMD mechanism permit more sensitive post-transcriptional gene regulation but can have severe deleterious consequences, including the failure to degrade pathogenic aberrant mRNAs in many B cell lymphomas. This article is categorized under: RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms.
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Affiliation(s)
- Aparna Kishor
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Sarah E Fritz
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - J Robert Hogg
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
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32
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Mazloomian A, Araki S, Ohori M, El-Naggar AM, Yap D, Bashashati A, Nakao S, Sorensen PH, Nakanishi A, Shah S, Aparicio S. Pharmacological systems analysis defines EIF4A3 functions in cell-cycle and RNA stress granule formation. Commun Biol 2019; 2:165. [PMID: 31069274 PMCID: PMC6499833 DOI: 10.1038/s42003-019-0391-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/11/2019] [Indexed: 12/13/2022] Open
Abstract
The RNA helicase EIF4A3 regulates the exon junction complex and nonsense-mediated mRNA decay functions in RNA transcript processing. However, a transcriptome-wide network definition of these functions has been lacking, in part due to the lack of suitable pharmacological inhibitors. Here we employ short-duration graded EIF4A3 inhibition using small molecule allosteric inhibitors to define the transcriptome-wide dependencies of EIF4A3. We thus define conserved cellular functions, such as cell cycle control, that are EIF4A3 dependent. We show that EIF4A3-dependent splicing reactions have a distinct genome-wide pattern of associated RNA-binding protein motifs. We also uncover an unanticipated role of EIF4A3 in the biology of RNA stress granules, which sequester and silence the translation of most mRNAs under stress conditions and are implicated in cell survival and tumour progression. We show that stress granule induction and maintenance is suppressed on the inhibition of EIF4A3, in part through EIF4A3-associated regulation of G3BP1 and TIA1 scaffold protein expression.
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Affiliation(s)
- Alborz Mazloomian
- Department of Molecular Oncology, BC Cancer, part of the Provincial Health Services Authority, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
- Department of Pathology and Laboratory Medicine, G227-2211 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 2B5 Canada
| | - Shinsuke Araki
- Research Department, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555 Japan
| | - Momoko Ohori
- Research Department, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555 Japan
| | - Amal M. El-Naggar
- Department of Molecular Oncology, BC Cancer, part of the Provincial Health Services Authority, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
- Department of Pathology and Laboratory Medicine, G227-2211 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 2B5 Canada
- Department of Pathology, Faculty of Medicine, Menoufia University, Menoufia Governorate, Egypt
| | - Damian Yap
- Department of Molecular Oncology, BC Cancer, part of the Provincial Health Services Authority, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
- Department of Pathology and Laboratory Medicine, G227-2211 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 2B5 Canada
| | - Ali Bashashati
- Department of Molecular Oncology, BC Cancer, part of the Provincial Health Services Authority, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
- Department of Pathology and Laboratory Medicine, G227-2211 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 2B5 Canada
| | - Shoichi Nakao
- Research Department, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555 Japan
| | - Poul H. Sorensen
- Department of Molecular Oncology, BC Cancer, part of the Provincial Health Services Authority, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
- Department of Pathology and Laboratory Medicine, G227-2211 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 2B5 Canada
| | - Atsushi Nakanishi
- Research Department, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555 Japan
| | - Sohrab Shah
- Department of Molecular Oncology, BC Cancer, part of the Provincial Health Services Authority, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
- Department of Pathology and Laboratory Medicine, G227-2211 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 2B5 Canada
- Department of Epidemiology & Biostatistics, Memorial Sloan Kettering Cancer Center, 417 E68th St, New York, NY 10065 USA
| | - Samuel Aparicio
- Department of Molecular Oncology, BC Cancer, part of the Provincial Health Services Authority, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
- Department of Pathology and Laboratory Medicine, G227-2211 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 2B5 Canada
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33
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Identification of antiviral roles for the exon-junction complex and nonsense-mediated decay in flaviviral infection. Nat Microbiol 2019; 4:985-995. [PMID: 30833725 PMCID: PMC6533143 DOI: 10.1038/s41564-019-0375-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/18/2019] [Indexed: 12/31/2022]
Abstract
West Nile virus (WNV) is an emerging mosquito-borne flavivirus, related to dengue virus and Zika virus. To gain insight into host pathways involved in WNV infection, we performed a systematic affinity-tag purification mass spectrometry (AP-MS) study to identify 259 WNV-interacting human proteins. RNAi screening revealed 26 genes that both interact with WNV proteins and influence WNV infection. We found that WNV, dengue and Zika virus capsids interact with a conserved subset of proteins that impact infection. These include the exon-junction complex (EJC) recycling factor, PYM1, which is antiviral against all three viruses. The EJC has roles in nonsense-mediated decay (NMD), and we found that both the EJC and NMD are antiviral and the EJC protein RBM8A directly binds WNV RNA. To counteract this, flavivirus infection inhibits NMD and the capsid-PYM1 interaction interferes with EJC protein function and localization. Depletion of PYM1 attenuates RBM8A binding to viral RNA, suggesting that WNV sequesters PYM1 to protect viral RNA from decay. Together, these data suggest a complex interplay between the virus and host in regulating NMD and the EJC.
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34
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Karousis ED, Mühlemann O. Nonsense-Mediated mRNA Decay Begins Where Translation Ends. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032862. [PMID: 29891560 DOI: 10.1101/cshperspect.a032862] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is arguably the best-studied eukaryotic messenger RNA (mRNA) surveillance pathway, yet fundamental questions concerning the molecular mechanism of target RNA selection remain unsolved. Besides degrading defective mRNAs harboring premature termination codons (PTCs), NMD also targets many mRNAs encoding functional full-length proteins. Thus, NMD impacts on a cell's transcriptome and is implicated in a range of biological processes that affect a broad spectrum of cellular homeostasis. Here, we focus on the steps involved in the recognition of NMD targets and the activation of NMD. We summarize the accumulating evidence that tightly links NMD to translation termination and we further discuss the recruitment and activation of the mRNA degradation machinery and the regulation of this complex series of events. Finally, we review emerging ideas concerning the mechanistic details of NMD activation and the potential role of NMD as a general surveyor of translation efficacy.
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Affiliation(s)
- Evangelos D Karousis
- Department of Chemistry and Biochemistry, University of Bern, CH-3012 Bern, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, CH-3012 Bern, Switzerland
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35
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Abstract
Nonsense-mediated mRNA decay is a eukaryotic pathway that degrades transcripts with premature termination codons (PTCs). In most eukaryotes, thousands of transcripts are degraded by NMD, including many important regulators of developmental and stress response pathways. Transcripts can be targeted to NMD by the presence of an upstream ORF or by introduction of a PTC through alternative splicing. Many factors involved in the recognition of PTCs and the destruction of NMD targets have been characterized. While some are highly conserved, others have been repeatedly lost in eukaryotic lineages. Here, I detail the factors involved in NMD, our current understanding of their interactions and how they have evolved. I outline a classification system to describe NMD pathways based on the presence/absence of key NMD factors. These types of NMD pathways exist in multiple different lineages, indicating the plasticity of the NMD pathway through recurrent losses of NMD factors during eukaryotic evolution. By classifying the NMD pathways in this way, gaps in our understanding are revealed, even within well studied organisms. Finally, I discuss the likely driving force behind the origins of the NMD pathway before the appearance of the last eukaryotic common ancestor: transposable element expansion and the consequential origin of introns.
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Affiliation(s)
- James P B Lloyd
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia
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36
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Abstract
Nonsense-mediated mRNA decay is a eukaryotic pathway that degrades transcripts with premature termination codons (PTCs). In most eukaryotes, thousands of transcripts are degraded by NMD, including many important regulators of developmental and stress response pathways. Transcripts can be targeted to NMD by the presence of an upstream ORF or by introduction of a PTC through alternative splicing. Many factors involved in the recognition of PTCs and the destruction of NMD targets have been characterized. While some are highly conserved, others have been repeatedly lost in eukaryotic lineages. Here, I detail the factors involved in NMD, our current understanding of their interactions and how they have evolved. I outline a classification system to describe NMD pathways based on the presence/absence of key NMD factors. These types of NMD pathways exist in multiple different lineages, indicating the plasticity of the NMD pathway through recurrent losses of NMD factors during eukaryotic evolution. By classifying the NMD pathways in this way, gaps in our understanding are revealed, even within well studied organisms. Finally, I discuss the likely driving force behind the origins of the NMD pathway before the appearance of the last eukaryotic common ancestor: transposable element expansion and the consequential origin of introns.
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Affiliation(s)
- James P B Lloyd
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia
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37
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Coban-Akdemir Z, White JJ, Song X, Jhangiani SN, Fatih JM, Gambin T, Bayram Y, Chinn IK, Karaca E, Punetha J, Poli C, Boerwinkle E, Shaw CA, Orange JS, Gibbs RA, Lappalainen T, Lupski JR, Carvalho CM, Carvalho CMB. Identifying Genes Whose Mutant Transcripts Cause Dominant Disease Traits by Potential Gain-of-Function Alleles. Am J Hum Genet 2018; 103:171-187. [PMID: 30032986 DOI: 10.1016/j.ajhg.2018.06.009] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/14/2018] [Indexed: 12/14/2022] Open
Abstract
Premature termination codon (PTC)-bearing transcripts are often degraded by nonsense-mediated decay (NMD) resulting in loss-of-function (LoF) alleles. However, not all PTCs result in LoF mutations, i.e., some such transcripts escape NMD and are translated to truncated peptide products that result in disease due to gain-of-function (GoF) effects. Since the location of the PTC is a major factor determining transcript fate, we hypothesized that depletion of protein-truncating variants (PTVs) within the gene region predicted to escape NMD in control databases could provide a rank for genic susceptibility for disease through GoF versus LoF. We developed an NMD escape intolerance score to rank genes based on the depletion of PTVs that would render them able to escape NMD using the Atherosclerosis Risk in Communities Study (ARIC) and the Exome Aggregation Consortium (ExAC) control databases, which was further used to screen the Baylor-Center for Mendelian Genomics disease database. This analysis revealed 1,996 genes significantly depleted for PTVs that are predicted to escape from NMD, i.e., PTVesc; further studies provided evidence that revealed a subset as candidate genes underlying Mendelian phenotypes. Importantly, these genes have characteristically low pLI scores, which can cause them to be overlooked as candidates for dominant diseases. Collectively, we demonstrate that this NMD escape intolerance score is an effective and efficient tool for gene discovery in Mendelian diseases due to production of truncated or altered proteins. More importantly, we provide a complementary analytical tool to aid identification of genes associated with dominant traits through a mechanism distinct from LoF.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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38
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Wang Z, Ballut L, Barbosa I, Le Hir H. Exon Junction Complexes can have distinct functional flavours to regulate specific splicing events. Sci Rep 2018; 8:9509. [PMID: 29934576 PMCID: PMC6015020 DOI: 10.1038/s41598-018-27826-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 06/11/2018] [Indexed: 11/09/2022] Open
Abstract
The exon junction complex (EJC) deposited on spliced mRNAs, plays a central role in the post-transcriptional gene regulation and specific gene expression. The EJC core complex is associated with multiple peripheral factors involved in various post-splicing events. Here, using recombinant complex reconstitution and transcriptome-wide analysis, we showed that the EJC peripheral protein complexes ASAP and PSAP form distinct complexes with the EJC core and can confer to EJCs distinct alternative splicing regulatory activities. This study provides the first evidence that different EJCs can have distinct functions, illuminating EJC-dependent gene regulation.
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Affiliation(s)
- Zhen Wang
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, F-75005, France
| | - Lionel Ballut
- Institut de Biologie et Chimie des Protéines, CNRS UMR5086, Université de Lyon 1, Lyon, France
| | - Isabelle Barbosa
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, F-75005, France
| | - Hervé Le Hir
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Research University, Paris, F-75005, France.
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39
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Multiple Nonsense-Mediated mRNA Processes Require Smg5 in Drosophila. Genetics 2018; 209:1073-1084. [PMID: 29903866 DOI: 10.1534/genetics.118.301140] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 06/09/2018] [Indexed: 01/09/2023] Open
Abstract
The nonsense-mediated messenger RNA (mRNA) decay (NMD) pathway is a cellular quality control and post-transcriptional gene regulatory mechanism and is essential for viability in most multicellular organisms . A complex of proteins has been identified to be required for NMD function to occur; however, there is an incomplete understanding of the individual contributions of each of these factors to the NMD process. Central to the NMD process are three proteins, Upf1 (SMG-2), Upf2 (SMG-3), and Upf3 (SMG-4), which are found in all eukaryotes, with Upf1 and Upf2 being absolutely required for NMD in all organisms in which their functions have been examined. The other known NMD factors, Smg1, Smg5, Smg6, and Smg7, are more variable in their presence in different orders of organisms and are thought to have a more regulatory role. Here we present the first genetic analysis of the NMD factor Smg5 in Drosophila Surprisingly, we find that unlike the other analyzed Smg genes in this organism, Smg5 is essential for NMD activity. We found this is due in part to a requirement for Smg5 in both the activity of Smg6-dependent endonucleolytic cleavage, as well as an additional Smg6-independent mechanism. Redundancy between these degradation pathways explains why some Drosophila NMD genes are not required for all NMD-pathway activity. We also found that while the NMD component Smg1 has only a minimal role in Drosophila NMD during normal conditions, it becomes essential when NMD activity is compromised by partial loss of Smg5 function. Our findings suggest that not all NMD complex components are required for NMD function at all times, but instead are utilized in a context-dependent manner in vivo.
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40
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New insights into the interplay between the translation machinery and nonsense-mediated mRNA decay factors. Biochem Soc Trans 2018; 46:503-512. [PMID: 29626148 PMCID: PMC6008592 DOI: 10.1042/bst20170427] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 12/13/2022]
Abstract
Faulty mRNAs with a premature stop codon (PTC) are recognized and degraded by nonsense-mediated mRNA decay (NMD). Recognition of a nonsense mRNA depends on translation and on the presence of NMD-enhancing or the absence of NMD-inhibiting factors in the 3'-untranslated region. Our review summarizes our current understanding of the molecular function of the conserved NMD factors UPF3B and UPF1, and of the anti-NMD factor Poly(A)-binding protein, and their interactions with ribosomes translating PTC-containing mRNAs. Our recent discovery that UPF3B interferes with human translation termination and enhances ribosome dissociation in vitro, whereas UPF1 is inactive in these assays, suggests a re-interpretation of previous experiments and modification of prevalent NMD models. Moreover, we discuss recent work suggesting new functions of the key NMD factor UPF1 in ribosome recycling, inhibition of translation re-initiation and nascent chain ubiquitylation. These new findings suggest that the interplay of UPF proteins with the translation machinery is more intricate than previously appreciated, and that this interplay quality-controls the efficiency of termination, ribosome recycling and translation re-initiation.
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41
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Baird TD, Cheng KCC, Chen YC, Buehler E, Martin SE, Inglese J, Hogg JR. ICE1 promotes the link between splicing and nonsense-mediated mRNA decay. eLife 2018. [PMID: 29528287 PMCID: PMC5896957 DOI: 10.7554/elife.33178] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The nonsense-mediated mRNA decay (NMD) pathway detects aberrant transcripts containing premature termination codons (PTCs) and regulates expression of 5–10% of non-aberrant human mRNAs. To date, most proteins involved in NMD have been identified by genetic screens in model organisms; however, the increased complexity of gene expression regulation in human cells suggests that additional proteins may participate in the human NMD pathway. To identify proteins required for NMD, we performed a genome-wide RNAi screen against >21,000 genes. Canonical members of the NMD pathway were highly enriched as top hits in the siRNA screen, along with numerous candidate NMD factors, including the conserved ICE1/KIAA0947 protein. RNAseq studies reveal that depletion of ICE1 globally enhances accumulation and stability of NMD-target mRNAs. Further, our data suggest that ICE1 uses a putative MIF4G domain to interact with exon junction complex (EJC) proteins and promotes the association of the NMD protein UPF3B with the EJC. The DNA in our cells contains the hereditary information that makes each of us unique. Molecules called mRNAs are copies of this information and are used as templates for making proteins. When a strand of incorrectly copied mRNA, or one including errors from the original DNA template, is recognized, our cells destroy the mRNA to prevent it from producing a damaged protein. Organisms from yeast to humans have evolved a mechanism for finding and destroying faulty mRNAs, called mRNA surveillance. Animals are particularly reliant on mRNA surveillance, as their proteins are often made from cutting and pasting together mRNA from different portions of DNA, in a process known as splicing. Despite being a vital process, we still lack a good understanding of how mRNA surveillance works. Now, Baird et al. used human kidney cells that produced an error-containing mRNA that could be tracked. To investigate how efficient RNA surveillance is under different conditions, the levels of individual proteins were reduced one at a time. By tracking the amount of faulty mRNA, it was possible to find out if a single protein plays a role in human mRNA surveillance. If the number of faulty mRNAs is high when a protein is reduced, it suggests that this protein may be involved in mRNA surveillance. Baird et al. screened more than 21,000 proteins, the majority of proteins made in human cells. Many of the proteins that stood out as important in mRNA surveillance were the ones already known to be relevant in yeast and worm cells. But the experiments also identified new proteins that appear to play a role specifically in human RNA surveillance. One of the proteins, ICE1, is essential for the relationship between mRNA splicing and mRNA surveillance. Without ICE1, the mRNA surveillance machinery can no longer find and destroy faulty mRNAs. Nearly one-third of genetic diseases are caused by mutations that result in faulty mRNAs, which can be detected by mRNA surveillance pathways. Depending on the disease, destroying these error-containing mRNAs can either improve or worsen disease symptoms. A better understanding of the factors that control human RNA surveillance could one day help to develop treatments that affect mRNA surveillance to improve disease outcomes.
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Affiliation(s)
- Thomas D Baird
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Ken Chih-Chien Cheng
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, United States
| | - Yu-Chi Chen
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, United States
| | - Eugen Buehler
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, United States
| | - Scott E Martin
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, United States
| | - James Inglese
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, United States
| | - J Robert Hogg
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
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42
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The exon junction complex: structural insights into a faithful companion of mammalian mRNPs. Biochem Soc Trans 2018; 46:153-161. [PMID: 29351963 DOI: 10.1042/bst20170059] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/13/2017] [Accepted: 12/18/2017] [Indexed: 12/21/2022]
Abstract
During splicing, the exon junction complex (EJC) is deposited upstream of exon-exon boundaries. The EJC and its peripheral bound proteins play an essential role in mediating mRNA export, translation and turnover. However, the exact sequence of EJC assembly and the involved factors during splicing remain elusive. Recently published structures of the human C* spliceosome clarified the position of the EJC at this phase of splicing and have given insight into previously unidentified interactions between the EJC and spliceosomal proteins. Here, these new observations are presented and the significance for EJC assembly is discussed. Furthermore, the vast landscape of EJC interacting proteins and their manifold functions are described. Finally, the factors involved in EJC disassembly and recycling are recapitulated. This review aims to integrate structural, biochemical and physiological data to obtain a comprehensive picture of EJC components during the lifetime of the EJC.
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43
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Gupta P, Li YR. Upf proteins: highly conserved factors involved in nonsense mRNA mediated decay. Mol Biol Rep 2017; 45:39-55. [PMID: 29282598 DOI: 10.1007/s11033-017-4139-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/14/2017] [Indexed: 11/28/2022]
Abstract
Over 10% of genetic diseases are caused by mutations that introduce a premature termination codon in protein-coding mRNA. Nonsense-mediated mRNA decay (NMD) is an essential cellular pathway that degrades these mRNAs to prevent the accumulation of harmful partial protein products. NMD machinery is also increasingly appreciated to play a role in other essential cellular functions, including telomere homeostasis and the regulation of normal mRNA turnover, and is misregulated in numerous cancers. Hence, understanding and designing therapeutics targeting NMD is an important goal in biomedical science. The central regulator of NMD, the Upf1 protein, interacts with translation termination factors and contextual factors to initiate NMD specifically on mRNAs containing PTCs. The molecular details of how these contextual factors affect Upf1 function remain poorly understood. Here, we review plausible models for the NMD pathway and the evidence for the variety of roles NMD machinery may play in different cellular processes.
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Affiliation(s)
- Puneet Gupta
- Harvard College, Harvard University, Cambridge, MA, 02138, USA.,School of Arts and Sciences, St. Bonaventure University, St. Bonaventure, NY, 14778, USA
| | - Yan-Ruide Li
- Harvard Medical School, Harvard University, Boston, MA, 02115, USA. .,College of Life Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, 310058, China.
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44
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Neu-Yilik G, Raimondeau E, Eliseev B, Yeramala L, Amthor B, Deniaud A, Huard K, Kerschgens K, Hentze MW, Schaffitzel C, Kulozik AE. Dual function of UPF3B in early and late translation termination. EMBO J 2017; 36:2968-2986. [PMID: 28899899 PMCID: PMC5641913 DOI: 10.15252/embj.201797079] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 08/07/2017] [Accepted: 08/10/2017] [Indexed: 11/09/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a cellular surveillance pathway that recognizes and degrades mRNAs with premature termination codons (PTCs). The mechanisms underlying translation termination are key to the understanding of RNA surveillance mechanisms such as NMD and crucial for the development of therapeutic strategies for NMD-related diseases. Here, we have used a fully reconstituted in vitro translation system to probe the NMD proteins for interaction with the termination apparatus. We discovered that UPF3B (i) interacts with the release factors, (ii) delays translation termination and (iii) dissociates post-termination ribosomal complexes that are devoid of the nascent peptide. Furthermore, we identified UPF1 and ribosomes as new interaction partners of UPF3B. These previously unknown functions of UPF3B during the early and late phases of translation termination suggest that UPF3B is involved in the crosstalk between the NMD machinery and the PTC-bound ribosome, a central mechanistic step of RNA surveillance.
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Affiliation(s)
- Gabriele Neu-Yilik
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Heidelberg, Germany.,Hopp Kindertumorzentrum am NCT Heidelberg, Heidelberg, Germany
| | | | - Boris Eliseev
- European Molecular Biology Laboratory, Grenoble, France
| | | | - Beate Amthor
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Karine Huard
- European Molecular Biology Laboratory, Grenoble, France
| | - Kathrin Kerschgens
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Heidelberg, Germany
| | - Matthias W Hentze
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Heidelberg, Germany .,European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christiane Schaffitzel
- European Molecular Biology Laboratory, Grenoble, France .,School of Biochemistry, University of Bristol, Bristol, UK
| | - Andreas E Kulozik
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany .,Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Heidelberg, Germany.,Hopp Kindertumorzentrum am NCT Heidelberg, Heidelberg, Germany
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45
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Quévillon Huberdeau M, Zeitler DM, Hauptmann J, Bruckmann A, Fressigné L, Danner J, Piquet S, Strieder N, Engelmann JC, Jannot G, Deutzmann R, Simard MJ, Meister G. Phosphorylation of Argonaute proteins affects mRNA binding and is essential for microRNA-guided gene silencing in vivo. EMBO J 2017. [PMID: 28645918 DOI: 10.15252/embj.201696386] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Argonaute proteins associate with microRNAs and are key components of gene silencing pathways. With such a pivotal role, these proteins represent ideal targets for regulatory post-translational modifications. Using quantitative mass spectrometry, we find that a C-terminal serine/threonine cluster is phosphorylated at five different residues in human and Caenorhabditis elegans In human, hyper-phosphorylation does not affect microRNA binding, localization, or cleavage activity of Ago2. However, mRNA binding is strongly affected. Strikingly, on Ago2 mutants that cannot bind microRNAs or mRNAs, the cluster remains unphosphorylated indicating a role at late stages of gene silencing. In C. elegans, the phosphorylation of the conserved cluster of ALG-1 is essential for microRNA function in vivo Furthermore, a single point mutation within the cluster is sufficient to phenocopy the loss of its complete phosphorylation. Interestingly, this mutant retains its capacity to produce and bind microRNAs and represses expression when artificially tethered to an mRNA Altogether, our data suggest that the phosphorylation state of the serine/threonine cluster is important for Argonaute-mRNA interactions.
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Affiliation(s)
- Miguel Quévillon Huberdeau
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (L'Hôtel-Dieu de Québec), Quebec City, Québec, Canada.,Laval University Cancer Research Centre, Quebec City, Québec, Canada
| | - Daniela M Zeitler
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
| | - Judith Hauptmann
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
| | - Astrid Bruckmann
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
| | - Lucile Fressigné
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (L'Hôtel-Dieu de Québec), Quebec City, Québec, Canada.,Laval University Cancer Research Centre, Quebec City, Québec, Canada
| | - Johannes Danner
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
| | - Sandra Piquet
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (L'Hôtel-Dieu de Québec), Quebec City, Québec, Canada.,Laval University Cancer Research Centre, Quebec City, Québec, Canada
| | - Nicholas Strieder
- Department of Statistical Bioinformatics, University of Regensburg, Regensburg, Germany
| | - Julia C Engelmann
- Department of Statistical Bioinformatics, University of Regensburg, Regensburg, Germany
| | - Guillaume Jannot
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (L'Hôtel-Dieu de Québec), Quebec City, Québec, Canada.,Laval University Cancer Research Centre, Quebec City, Québec, Canada
| | - Rainer Deutzmann
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
| | - Martin J Simard
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (L'Hôtel-Dieu de Québec), Quebec City, Québec, Canada .,Laval University Cancer Research Centre, Quebec City, Québec, Canada
| | - Gunter Meister
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, Regensburg, Germany
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46
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Nickless A, Bailis JM, You Z. Control of gene expression through the nonsense-mediated RNA decay pathway. Cell Biosci 2017; 7:26. [PMID: 28533900 PMCID: PMC5437625 DOI: 10.1186/s13578-017-0153-7] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 05/12/2017] [Indexed: 11/25/2022] Open
Abstract
Nonsense-mediated RNA decay (NMD) was originally discovered as a cellular surveillance pathway that safeguards the quality of mRNA transcripts in eukaryotic cells. In its canonical function, NMD prevents translation of mutant mRNAs harboring premature termination codons (PTCs) by targeting them for degradation. However, recent studies have shown that NMD has a much broader role in gene expression by regulating the stability of many normal transcripts. In this review, we discuss the function of NMD in normal physiological processes, its dynamic regulation by developmental and environmental cues, and its association with human disease.
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Affiliation(s)
- Andrew Nickless
- Department of Cell Biology & Physiology, Washington University School of Medicine, Campus Box 8228, 660 S. Euclid Ave., St. Louis, MO 63110 USA
| | - Julie M Bailis
- Department of Oncology Research, Amgen, South San Francisco, CA 94080 USA
| | - Zhongsheng You
- Department of Cell Biology & Physiology, Washington University School of Medicine, Campus Box 8228, 660 S. Euclid Ave., St. Louis, MO 63110 USA
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47
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Deka B, Singh KK. Multifaceted Regulation of Gene Expression by the Apoptosis- and Splicing-Associated Protein Complex and Its Components. Int J Biol Sci 2017; 13:545-560. [PMID: 28539829 PMCID: PMC5441173 DOI: 10.7150/ijbs.18649] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/24/2017] [Indexed: 11/24/2022] Open
Abstract
The differential deposition of RNA-binding proteins (RBPs) on pre-mRNA mediates the processes of gene expression. One of the complexes containing RBPs that play a crucial part in RNA metabolism is the apoptosis-and splicing-associated protein (ASAP) complex. In this review, we present a summary of the structure of ASAP complex and its localization. Also, we discuss the findings by different groups on various functions of the subunits of the ASAP complex in RNA metabolism. The subunits of the ASAP complex are RNPS1, Acinus and SAP18. Originally, the ASAP complex was thought to link RNA processing with apoptosis. Further studies have shown the role of these components in RNA metabolism of cells, including transcription, splicing, translation and nonsense-mediated mRNA decay (NMD). In transcription, RNPS1 is involved in preventing the formation of R-loop, while Acinus and SAP18 suppress transcription with the help of histone deacetylase. On the one hand, individual components of the ASAP complex, namely RNPS1 and Acinus act as splicing activators, whereas on the other hand, in-vitro assay shows that the ASAP complex behaves as splicing repressor. In addition, the individual members of the ASAP complex associates with the exon junction complex (EJC) to play roles in splicing and translation. RNPS1 increases the translation efficiency by participating in the 3'end processing and polysome association of mRNAs. Similarly, during NMD RNPS1 aids in the recruitment of decay factors by interacting with EJC.
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Affiliation(s)
| | - Kusum Kumari Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
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48
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Liang R, Lin Y, Ye JZ, Yan XX, Liu ZH, Li YQ, Luo XL, Ye HH. High expression of RBM8A predicts poor patient prognosis and promotes tumor progression in hepatocellular carcinoma. Oncol Rep 2017; 37:2167-2176. [PMID: 28259942 DOI: 10.3892/or.2017.5457] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/30/2017] [Indexed: 11/06/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a huge threat for human health worldwide. As a complicated tumor, the molecular basis for HCC development especially metastasis requires exploration. Although RNA binding motif (RBM) proteins are closely related to various cancers, the clinical importance and underlying mechanisms of RBM8A in HCC remain elusive. In this study, we found that RBM8A was highly expressed in HCC tumor tissues compared to normal liver tissues. Overexpression of RBM8A was associated with HbsAg and Edmondson pathological grading. Moreover, Kaplan-Meier survival analysis showed that high expression of RBM8A was related to the poor overall survival and progression-free survival of patients with HCC. Gain- and loss-of-function experiments further demonstrated that RBM8A promoted tumor cell migration and invasion in HCC via activation of epithelial-mesenchymal transition signaling pathway. It is also noteworthy that RBM8A is required for tumor cell proliferation and anti-apoptosis in HCC. Altogether, our results revealed a close relationship between RBM8A and HCC prognosis as well as a critical tumor-promoting function of RBM8A in HCC progression, suggesting that RBM8A might be a potential bio-marker and drug target in HCC therapy.
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Affiliation(s)
- Rong Liang
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Yan Lin
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Jia-Zhou Ye
- Department of Hepatobilliary Surgery, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530022, P.R. China
| | - Xue-Xin Yan
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Zhi-Hui Liu
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Yong-Qiang Li
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Xiao-Ling Luo
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Hai-Hong Ye
- Department of Hepatobilliary Surgery, Affiliated Minzu Hospital of Guangxi Medical University, Nanning, Guangxi 530001, P.R. China
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49
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YTHDF3 facilitates translation and decay of N 6-methyladenosine-modified RNA. Cell Res 2017; 27:315-328. [PMID: 28106072 DOI: 10.1038/cr.2017.15] [Citation(s) in RCA: 1128] [Impact Index Per Article: 161.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/06/2016] [Accepted: 12/10/2016] [Indexed: 02/07/2023] Open
Abstract
N6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic messenger RNAs (mRNAs), and plays important roles in cell differentiation and tissue development. It regulates multiple steps throughout the RNA life cycle including RNA processing, translation, and decay, via the recognition by selective binding proteins. In the cytoplasm, m6A binding protein YTHDF1 facilitates translation of m6A-modified mRNAs, and YTHDF2 accelerates the decay of m6A-modified transcripts. The biological function of YTHDF3, another cytoplasmic m6A binder of the YTH (YT521-B homology) domain family, remains unknown. Here, we report that YTHDF3 promotes protein synthesis in synergy with YTHDF1, and affects methylated mRNA decay mediated through YTHDF2. Cells deficient in all three YTHDF proteins experience the most dramatic accumulation of m6A-modified transcripts. These results indicate that together with YTHDF1 and YTHDF2, YTHDF3 plays critical roles to accelerate metabolism of m6A-modified mRNAs in the cytoplasm. All three YTHDF proteins may act in an integrated and cooperative manner to impact fundamental biological processes related to m6A RNA methylation.
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50
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Boehm V, Gehring NH. Exon Junction Complexes: Supervising the Gene Expression Assembly Line. Trends Genet 2016; 32:724-735. [PMID: 27667727 DOI: 10.1016/j.tig.2016.09.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/23/2016] [Accepted: 09/01/2016] [Indexed: 12/16/2022]
Abstract
The exon junction complex (EJC) is an RNA-binding protein complex that is assembled and deposited onto mRNAs during splicing. The EJC comprises four core components that bind to not only canonical sites upstream of exon-exon junctions, but also to noncanonical sites at other positions in exons. EJC-associated proteins are recruited by the EJC at different steps of gene expression to execute the multiple functions of the EJC. Recently, new insights have been obtained into how EJCs stimulate pre-mRNA splicing, and mRNA export, translation, and degradation. Furthermore, mutations in EJC core components were shown to result in severe disorders in humans, demonstrating the critical physiological role of the EJC. Hence, the EJC has been identified as an important player in post-transcriptional gene regulation in metazoans.
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Affiliation(s)
- Volker Boehm
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
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