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Firdous Z, Kalra S, Chattopadhyay R, Bari VK. Current insight into the role of mRNA decay pathways in fungal pathogenesis. Microbiol Res 2024; 283:127671. [PMID: 38479232 DOI: 10.1016/j.micres.2024.127671] [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: 12/18/2023] [Revised: 02/19/2024] [Accepted: 02/29/2024] [Indexed: 04/17/2024]
Abstract
Pathogenic fungal species can cause superficial and mucosal infections, to potentially fatal systemic or invasive infections in humans. These infections are more common in immunocompromised or critically ill patients and have a significant morbidity and fatality rate. Fungal pathogens utilize several strategies to adapt the host environment resulting in efficient and comprehensive alterations in their cellular metabolism. Fungal virulence is regulated by several factors and post-transcriptional regulation mechanisms involving mRNA molecules are one of them. Post-transcriptional controls have emerged as critical regulatory mechanisms involved in the pathogenesis of fungal species. The untranslated upstream and downstream regions of the mRNA, as well as RNA-binding proteins, regulate morphogenesis and virulence by controlling mRNA degradation and stability. The limited number of available therapeutic drugs, the emergence of multidrug resistance, and high death rates associated with systemic fungal illnesses pose a serious risk to human health. Therefore, new antifungal treatments that specifically target mRNA pathway components can decrease fungal pathogenicity and when combined increase the effectiveness of currently available antifungal drugs. This review summarizes the mRNA degradation pathways and their role in fungal pathogenesis.
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Affiliation(s)
- Zulikha Firdous
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Sapna Kalra
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Rituja Chattopadhyay
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Vinay Kumar Bari
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India.
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2
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Lorenzo-Orts L, Pauli A. The molecular mechanisms underpinning maternal mRNA dormancy. Biochem Soc Trans 2024; 52:861-871. [PMID: 38477334 PMCID: PMC11088918 DOI: 10.1042/bst20231122] [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: 12/14/2023] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/14/2024]
Abstract
A large number of mRNAs of maternal origin are produced during oogenesis and deposited in the oocyte. Since transcription stops at the onset of meiosis during oogenesis and does not resume until later in embryogenesis, maternal mRNAs are the only templates for protein synthesis during this period. To ensure that a protein is made in the right place at the right time, the translation of maternal mRNAs must be activated at a specific stage of development. Here we summarize our current understanding of the sophisticated mechanisms that contribute to the temporal repression of maternal mRNAs, termed maternal mRNA dormancy. We discuss mechanisms at the level of the RNA itself, such as the regulation of polyadenine tail length and RNA modifications, as well as at the level of RNA-binding proteins, which often block the assembly of translation initiation complexes at the 5' end of an mRNA or recruit mRNAs to specific subcellular compartments. We also review microRNAs and other mechanisms that contribute to repressing translation, such as ribosome dormancy. Importantly, the mechanisms responsible for mRNA dormancy during the oocyte-to-embryo transition are also relevant to cellular quiescence in other biological contexts.
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Affiliation(s)
- Laura Lorenzo-Orts
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
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3
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Smith AB, Ganguly DR, Moore M, Bowerman AF, Janapala Y, Shirokikh NE, Pogson BJ, Crisp PA. Dynamics of mRNA fate during light stress and recovery: from transcription to stability and translation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:818-839. [PMID: 37947266 PMCID: PMC10952913 DOI: 10.1111/tpj.16531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 09/20/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
Transcript stability is an important determinant of its abundance and, consequently, translational output. Transcript destabilisation can be rapid and is well suited for modulating the cellular response. However, it is unclear the extent to which RNA stability is altered under changing environmental conditions in plants. We previously hypothesised that recovery-induced transcript destabilisation facilitated a phenomenon of rapid recovery gene downregulation (RRGD) in Arabidopsis thaliana (Arabidopsis) following light stress, based on mathematical calculations to account for ongoing transcription. Here, we test this hypothesis and investigate processes regulating transcript abundance and fate by quantifying changes in transcription, stability and translation before, during and after light stress. We adapt syringe infiltration to apply a transcriptional inhibitor to soil-grown plants in combination with stress treatments. Compared with measurements in juvenile plants and cell culture, we find reduced stability across a range of transcripts encoding proteins involved in RNA binding and processing. We also observe light-induced destabilisation of transcripts, followed by their stabilisation during recovery. We propose that this destabilisation facilitates RRGD, possibly in combination with transcriptional shut-off that was confirmed for HSP101, ROF1 and GOLS1. We also show that translation remains highly dynamic over the course of light stress and recovery, with a bias towards transcript-specific increases in ribosome association, independent of changes in total transcript abundance, after 30 min of light stress. Taken together, we provide evidence for the combinatorial regulation of transcription and stability that occurs to coordinate translation during light stress and recovery in Arabidopsis.
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Affiliation(s)
- Aaron B. Smith
- Research School of BiologyThe Australian National UniversityCanberraAustralian Capital Territory2601Australia
| | - Diep R. Ganguly
- CSIRO Synthetic Biology Future Science PlatformCanberraAustralian Capital Territory2601Australia
- Department of BiologyUniversity of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Marten Moore
- Research School of BiologyThe Australian National UniversityCanberraAustralian Capital Territory2601Australia
| | - Andrew F. Bowerman
- Research School of BiologyThe Australian National UniversityCanberraAustralian Capital Territory2601Australia
| | - Yoshika Janapala
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery InstituteMonash UniversityClaytonVictoria3800Australia
| | - Nikolay E. Shirokikh
- The John Curtin School of Medical Research, The Shine‐Dalgarno Centre for RNA InnovationThe Australian National UniversityCanberraAustralian Capital Territory2601Australia
| | - Barry J. Pogson
- Research School of BiologyThe Australian National UniversityCanberraAustralian Capital Territory2601Australia
| | - Peter A. Crisp
- School of Agriculture and Food SciencesThe University of QueenslandBrisbaneQueensland4072Australia
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Di Fraia D, Marino A, Lee JH, Kelmer Sacramento E, Baumgart M, Bagnoli S, Tomaz da Silva P, Kumar Sahu A, Siano G, Tiessen M, Terzibasi-Tozzini E, Gagneur J, Frydman J, Cellerino A, Ori A. Impaired biogenesis of basic proteins impacts multiple hallmarks of the aging brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.20.549210. [PMID: 38260253 PMCID: PMC10802395 DOI: 10.1101/2023.07.20.549210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Aging and neurodegeneration entail diverse cellular and molecular hallmarks. Here, we studied the effects of aging on the transcriptome, translatome, and multiple layers of the proteome in the brain of a short-lived killifish. We reveal that aging causes widespread reduction of proteins enriched in basic amino acids that is independent of mRNA regulation, and it is not due to impaired proteasome activity. Instead, we identify a cascade of events where aberrant translation pausing leads to reduced ribosome availability resulting in proteome remodeling independently of transcriptional regulation. Our research uncovers a vulnerable point in the aging brain's biology - the biogenesis of basic DNA/RNA binding proteins. This vulnerability may represent a unifying principle that connects various aging hallmarks, encompassing genome integrity and the biosynthesis of macromolecules.
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Affiliation(s)
- Domenico Di Fraia
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Antonio Marino
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Jae Ho Lee
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Mario Baumgart
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | | | - Pedro Tomaz da Silva
- School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
- Munich Center for Machine Learning, Munich, Germany
| | - Amit Kumar Sahu
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | | | - Max Tiessen
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | | | - Julien Gagneur
- School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
- Computational Health Center, Helmholtz Center Munich, Neuherberg, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Alessandro Cellerino
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
- BIO@SNS, Scuola Normale Superiore, Pisa, Italy
| | - Alessandro Ori
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
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Lorenzo-Orts L, Strobl M, Steinmetz B, Leesch F, Pribitzer C, Roehsner J, Schutzbier M, Dürnberger G, Pauli A. eIF4E1b is a non-canonical eIF4E protecting maternal dormant mRNAs. EMBO Rep 2024; 25:404-427. [PMID: 38177902 PMCID: PMC10883267 DOI: 10.1038/s44319-023-00006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 10/31/2023] [Accepted: 11/08/2023] [Indexed: 01/06/2024] Open
Abstract
Maternal mRNAs are essential for protein synthesis during oogenesis and early embryogenesis. To adapt translation to specific needs during development, maternal mRNAs are translationally repressed by shortening the polyA tails. While mRNA deadenylation is associated with decapping and degradation in somatic cells, maternal mRNAs with short polyA tails are stable. Here we report that the germline-specific eIF4E paralog, eIF4E1b, is essential for zebrafish oogenesis. eIF4E1b localizes to P-bodies in zebrafish embryos and binds to mRNAs with reported short or no polyA tails, including histone mRNAs. Loss of eIF4E1b results in reduced histone mRNA levels in early gonads, consistent with a role in mRNA storage. Using mouse and human eIF4E1Bs (in vitro) and zebrafish eIF4E1b (in vivo), we show that unlike canonical eIF4Es, eIF4E1b does not interact with eIF4G to initiate translation. Instead, eIF4E1b interacts with the translational repressor eIF4ENIF1, which is required for eIF4E1b localization to P-bodies. Our study is consistent with an important role of eIF4E1b in regulating mRNA dormancy and provides new insights into fundamental post-transcriptional regulatory principles governing early vertebrate development.
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Affiliation(s)
- Laura Lorenzo-Orts
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria.
| | - Marcus Strobl
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria
| | - Benjamin Steinmetz
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zurich, Switzerland
| | - Friederike Leesch
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Carina Pribitzer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria
| | - Josef Roehsner
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Michael Schutzbier
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria
| | - Gerhard Dürnberger
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030, Vienna, Austria.
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6
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Alagar Boopathy L, Beadle E, Xiao A, Garcia-Bueno Rico A, Alecki C, Garcia de-Andres I, Edelmeier K, Lazzari L, Amiri M, Vera M. The ribosome quality control factor Asc1 determines the fate of HSP70 mRNA on and off the ribosome. Nucleic Acids Res 2023; 51:6370-6388. [PMID: 37158240 PMCID: PMC10325905 DOI: 10.1093/nar/gkad338] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 04/16/2023] [Accepted: 04/20/2023] [Indexed: 05/10/2023] Open
Abstract
Cells survive harsh environmental conditions by potently upregulating molecular chaperones such as heat shock proteins (HSPs), particularly the inducible members of the HSP70 family. The life cycle of HSP70 mRNA in the cytoplasm is unique-it is translated during stress when most cellular mRNA translation is repressed and rapidly degraded upon recovery. Contrary to its 5' untranslated region's role in maximizing translation, we discovered that the HSP70 coding sequence (CDS) suppresses its translation via the ribosome quality control (RQC) mechanism. The CDS of the most inducible Saccharomyces cerevisiae HSP70 gene, SSA4, is uniquely enriched with low-frequency codons that promote ribosome stalling during heat stress. Stalled ribosomes are recognized by the RQC components Asc1p and Hel2p and two novel RQC components, the ribosomal proteins Rps28Ap and Rps19Bp. Surprisingly, RQC does not signal SSA4 mRNA degradation via No-Go-Decay. Instead, Asc1p destabilizes SSA4 mRNA during recovery from heat stress by a mechanism independent of ribosome binding and SSA4 codon optimality. Therefore, Asc1p operates in two pathways that converge to regulate the SSA4 mRNA life cycle during stress and recovery. Our research identifies Asc1p as a critical regulator of the stress response and RQC as the mechanism tuning HSP70 synthesis.
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Affiliation(s)
| | - Emma Beadle
- Department of Biochemistry. McGill University, Montreal, QuebecH3G 1Y6, Canada
| | - Alan RuoChen Xiao
- Department of Biochemistry. McGill University, Montreal, QuebecH3G 1Y6, Canada
| | | | - Celia Alecki
- Department of Biochemistry. McGill University, Montreal, QuebecH3G 1Y6, Canada
| | | | - Kyla Edelmeier
- Department of Biochemistry. McGill University, Montreal, QuebecH3G 1Y6, Canada
| | - Luca Lazzari
- Department of Biochemistry. McGill University, Montreal, QuebecH3G 1Y6, Canada
| | - Mehdi Amiri
- Department of Biochemistry. McGill University, Montreal, QuebecH3G 1Y6, Canada
| | - Maria Vera
- Department of Biochemistry. McGill University, Montreal, QuebecH3G 1Y6, Canada
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7
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Vijjamarri AK, Niu X, Vandermeulen MD, Onu C, Zhang F, Qiu H, Gupta N, Gaikwad S, Greenberg ML, Cullen PJ, Lin Z, Hinnebusch AG. Decapping factor Dcp2 controls mRNA abundance and translation to adjust metabolism and filamentation to nutrient availability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.05.522830. [PMID: 36711592 PMCID: PMC9881900 DOI: 10.1101/2023.01.05.522830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Degradation of most yeast mRNAs involves decapping by Dcp1/Dcp2. DEAD-box protein Dhh1 has been implicated as an activator of decapping, in coupling codon non-optimality to enhanced degradation, and as a translational repressor, but its functions in cells are incompletely understood. RNA-Seq analyses coupled with CAGE sequencing of all capped mRNAs revealed increased abundance of hundreds of mRNAs in dcp2 Δ cells that appears to result directly from impaired decapping rather than elevated transcription, which was confirmed by ChIP-Seq analysis of RNA Polymerase II occupancies genome-wide. Interestingly, only a subset of mRNAs requires Dhh1 for targeting by Dcp2, and also generally requires the other decapping activators Pat1, Lsm2, Edc3 or Scd6; whereas most of the remaining transcripts utilize NMD factors for Dcp2-mediated turnover. Neither inefficient translation initiation nor stalled elongation appears to be a major driver of Dhh1-enhanced mRNA degradation. Surprisingly, ribosome profiling revealed that dcp2 Δ confers widespread changes in relative TEs that generally favor well-translated mRNAs. Because ribosome biogenesis is reduced while capped mRNA abundance is increased by dcp2 Δ, we propose that an increased ratio of mRNA to ribosomes increases competition among mRNAs for limiting ribosomes to favor efficiently translated mRNAs in dcp2 Δ cells. Interestingly, genes involved in respiration or utilization of alternative carbon or nitrogen sources are derepressed, and both mitochondrial function and cell filamentation (a strategy for nutrient foraging) are elevated by dcp2 Δ, suggesting that mRNA decapping sculpts gene expression post-transcriptionally to fine-tune metabolic pathways and morphological transitions according to nutrient availability.
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Affiliation(s)
- Anil Kumar Vijjamarri
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Xiao Niu
- Department of Biology, Saint Louis University, St. Louis, MO
| | | | - Chisom Onu
- Department of Biological Sciences, Wayne State University, Detroit, MI
| | - Fan Zhang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Hongfang Qiu
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Neha Gupta
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Swati Gaikwad
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | | | - Paul J Cullen
- Department of Biological Sciences, State University of Buffalo, Buffalo, NY
| | - Zhenguo Lin
- Department of Biology, Saint Louis University, St. Louis, MO
| | - Alan G Hinnebusch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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8
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Hernández-Elvira M, Sunnerhagen P. Post-transcriptional regulation during stress. FEMS Yeast Res 2022; 22:6585650. [PMID: 35561747 PMCID: PMC9246287 DOI: 10.1093/femsyr/foac025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/25/2022] [Accepted: 05/10/2022] [Indexed: 11/12/2022] Open
Abstract
To remain competitive, cells exposed to stress of varying duration, rapidity of onset, and intensity, have to balance their expenditure on growth and proliferation versus stress protection. To a large degree dependent on the time scale of stress exposure, the different levels of gene expression control: transcriptional, post-transcriptional and post-translational, will be engaged in stress responses. The post-transcriptional level is appropriate for minute-scale responses to transient stress, and for recovery upon return to normal conditions. The turnover rate, translational activity, covalent modifications, and subcellular localisation of RNA species are regulated under stress by multiple cellular pathways. The interplay between these pathways is required to achieve the appropriate signalling intensity and prevent undue triggering of stress-activated pathways at low stress levels, avoid overshoot, and down-regulate the response in a timely fashion. As much of our understanding of post-transcriptional regulation has been gained in yeast, this review is written with a yeast bias, but attempts to generalise to other eukaryotes. It summarises aspects of how post-transcriptional events in eukaryotes mitigate short-term environmental stresses, and how different pathways interact to optimise the stress response under shifting external conditions.
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Affiliation(s)
- Mariana Hernández-Elvira
- Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, P.O. Box 462, S-405 30 Göteborg, Sweden
| | - Per Sunnerhagen
- Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, P.O. Box 462, S-405 30 Göteborg, Sweden
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9
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Naeli P, Winter T, Hackett AP, Alboushi L, Jafarnejad SM. The intricate balance between microRNA-induced mRNA decay and translational repression. FEBS J 2022; 290:2508-2524. [PMID: 35247033 DOI: 10.1111/febs.16422] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 02/08/2022] [Accepted: 03/03/2022] [Indexed: 12/23/2022]
Abstract
Post-transcriptional regulation of messenger RNAs (mRNAs) (i.e., mechanisms that control translation, stability and localization) is a critical focal point in spatiotemporal regulation of gene expression in response to changes in environmental conditions. The human genome encodes ~ 2000 microRNAs (miRNAs), each of which could control the expression of hundreds of protein-coding mRNAs by inducing translational repression and/or promoting mRNA decay. While mRNA degradation is a terminal event, translational repression is reversible and can be employed for rapid response to internal or external cues. Recent years have seen significant progress in our understanding of how miRNAs induce degradation or translational repression of the target mRNAs. Here, we review the recent findings that illustrate the cellular machinery that contributes to miRNA-induced silencing, with a focus on the factors that could influence translational repression vs. decay.
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Affiliation(s)
- Parisa Naeli
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
| | - Timothy Winter
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
| | - Angela P Hackett
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
| | - Lilas Alboushi
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
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10
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Roles of mRNA poly(A) tails in regulation of eukaryotic gene expression. Nat Rev Mol Cell Biol 2022; 23:93-106. [PMID: 34594027 PMCID: PMC7614307 DOI: 10.1038/s41580-021-00417-y] [Citation(s) in RCA: 173] [Impact Index Per Article: 86.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 02/06/2023]
Abstract
In eukaryotes, poly(A) tails are present on almost every mRNA. Early experiments led to the hypothesis that poly(A) tails and the cytoplasmic polyadenylate-binding protein (PABPC) promote translation and prevent mRNA degradation, but the details remained unclear. More recent data suggest that the role of poly(A) tails is much more complex: poly(A)-binding protein can stimulate poly(A) tail removal (deadenylation) and the poly(A) tails of stable, highly translated mRNAs at steady state are much shorter than expected. Furthermore, the rate of translation elongation affects deadenylation. Consequently, the interplay between poly(A) tails, PABPC, translation and mRNA decay has a major role in gene regulation. In this Review, we discuss recent work that is revolutionizing our understanding of the roles of poly(A) tails in the cytoplasm. Specifically, we discuss the roles of poly(A) tails in translation and control of mRNA stability and how poly(A) tails are removed by exonucleases (deadenylases), including CCR4-NOT and PAN2-PAN3. We also discuss how deadenylation rate is determined, the integration of deadenylation with other cellular processes and the function of PABPC. We conclude with an outlook for the future of research in this field.
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11
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Jennifer S, Corinna R, Thomas D, Nils L, Diethard M, Brigitte G. Going beyond the limit: Increasing global translation activity leads to increased productivity of recombinant secreted proteins in Pichia pastoris. Metab Eng 2022; 70:181-195. [DOI: 10.1016/j.ymben.2022.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/12/2022] [Accepted: 01/20/2022] [Indexed: 01/06/2023]
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12
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Kumar R, Khandelwal N, Chander Y, Nagori H, Verma A, Barua A, Godara B, Pal Y, Gulati BR, Tripathi BN, Barua S, Kumar N. S-adenosylmethionine-dependent methyltransferase inhibitor DZNep blocks transcription and translation of SARS-CoV-2 genome with a low tendency to select for drug-resistant viral variants. Antiviral Res 2021; 197:105232. [PMID: 34968527 PMCID: PMC8714615 DOI: 10.1016/j.antiviral.2021.105232] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/22/2021] [Accepted: 12/23/2021] [Indexed: 12/13/2022]
Abstract
We report the in vitro antiviral activity of DZNep (3-Deazaneplanocin A; an inhibitor of S-adenosylmethionine-dependent methyltransferase) against SARS-CoV-2, besides demonstrating its protective efficacy against lethal infection of infectious bronchitis virus (IBV, a member of the Coronaviridae family). DZNep treatment resulted in reduced synthesis of SARS-CoV-2 RNA and proteins without affecting other steps of viral life cycle. We demonstrated that deposition of N6-methyl adenosine (m6A) in SARS-CoV-2 RNA in the infected cells recruits heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), an RNA binding protein which serves as a m6A reader. DZNep inhibited the recruitment of hnRNPA1 at m6A-modified SARS-CoV-2 RNA which eventually suppressed the synthesis of the viral genome. In addition, m6A-marked RNA and hnRNPA1 interaction was also shown to regulate early translation to replication switch of SARS-CoV-2 genome. Furthermore, abrogation of methylation by DZNep also resulted in defective synthesis of the 5’ cap of viral RNA, thereby resulting in its failure to interact with eIF4E (a cap-binding protein), eventually leading to a decreased synthesis of viral proteins. Most importantly, DZNep-resistant mutants could not be observed upon long-term sequential passage of SARS-CoV-2 in cell culture. In summary, we report the novel role of methylation in the life cycle of SARS-CoV-2 and propose that targeting the methylome using DZNep could be of significant therapeutic value against SARS-CoV-2 infection.
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Affiliation(s)
- Ram Kumar
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Nitin Khandelwal
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Yogesh Chander
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Himanshu Nagori
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Assim Verma
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Aditya Barua
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Bhagraj Godara
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Yash Pal
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Baldev R Gulati
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India
| | - Bhupendra N Tripathi
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India.
| | - Sanjay Barua
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India.
| | - Naveen Kumar
- National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, India.
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13
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Shah A, Bhandari R. IP6K1 upregulates the formation of processing bodies by influencing protein-protein interactions on the mRNA cap. J Cell Sci 2021; 134:273758. [PMID: 34841428 DOI: 10.1242/jcs.259117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/11/2021] [Indexed: 11/20/2022] Open
Abstract
Inositol hexakisphosphate kinase 1 (IP6K1) is a small molecule kinase that catalyzes the conversion of the inositol phosphate IP6 to 5-IP7. We show that IP6K1 acts independently of its catalytic activity to upregulate the formation of processing bodies (P-bodies), which are cytoplasmic ribonucleoprotein granules that store translationally repressed mRNA. IP6K1 does not localise to P-bodies, but instead binds to ribosomes, where it interacts with the mRNA decapping complex - the scaffold protein EDC4, activator proteins DCP1A/B, decapping enzyme DCP2 and RNA helicase DDX6. Along with its partner 4E-T, DDX6 is known to nucleate protein-protein interactions on the 5' mRNA cap to facilitate P-body formation. IP6K1 binds the translation initiation complex eIF4F on the mRNA cap, augmenting the interaction of DDX6 with 4E-T (also known as EIF4ENIF1) and the cap-binding protein eIF4E. Cells with reduced IP6K1 show downregulated microRNA-mediated translational suppression and increased stability of DCP2-regulated transcripts. Our findings unveil IP6K1 as a novel facilitator of proteome remodelling on the mRNA cap, tipping the balance in favour of translational repression over initiation, thus leading to P-body assembly. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Akruti Shah
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal 576104, India
| | - Rashna Bhandari
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India
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14
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Disrupting upstream translation in mRNAs is associated with human disease. Nat Commun 2021; 12:1515. [PMID: 33750777 PMCID: PMC7943595 DOI: 10.1038/s41467-021-21812-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 02/12/2021] [Indexed: 12/04/2022] Open
Abstract
Ribosome-profiling has uncovered pervasive translation in non-canonical open reading frames, however the biological significance of this phenomenon remains unclear. Using genetic variation from 71,702 human genomes, we assess patterns of selection in translated upstream open reading frames (uORFs) in 5’UTRs. We show that uORF variants introducing new stop codons, or strengthening existing stop codons, are under strong negative selection comparable to protein-coding missense variants. Using these variants, we map and validate gene-disease associations in two independent biobanks containing exome sequencing from 10,900 and 32,268 individuals, respectively, and elucidate their impact on protein expression in human cells. Our results suggest translation disrupting mechanisms relating uORF variation to reduced protein expression, and demonstrate that translation at uORFs is genetically constrained in 50% of human genes. The significance of translated upstream open reading frames is not well known. Here, the authors investigate genetic variants in these regions, finding that they are under high evolutionary constraint and may contribute to disease.
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15
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Hia F, Takeuchi O. The effects of codon bias and optimality on mRNA and protein regulation. Cell Mol Life Sci 2021; 78:1909-1928. [PMID: 33128106 PMCID: PMC11072601 DOI: 10.1007/s00018-020-03685-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 10/05/2020] [Accepted: 10/12/2020] [Indexed: 12/25/2022]
Abstract
The central dogma of molecular biology entails that genetic information is transferred from nucleic acid to proteins. Notwithstanding retro-transcribing genetic elements, DNA is transcribed to RNA which in turn is translated into proteins. Recent advancements have shown that each stage is regulated to control protein abundances for a variety of essential physiological processes. In this regard, mRNA regulation is essential in fine-tuning or calibrating protein abundances. In this review, we would like to discuss one of several mRNA-intrinsic features of mRNA regulation that has been gaining traction of recent-codon bias and optimality. Specifically, we address the effects of codon bias with regard to codon optimality in several biological processes centred on translation, such as mRNA stability and protein folding among others. Finally, we examine how different organisms or cell types, through this system, are able to coordinate physiological pathways to respond to a variety of stress or growth conditions.
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Affiliation(s)
- Fabian Hia
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Osamu Takeuchi
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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16
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Cantu F, Cao S, Hernandez C, Dhungel P, Spradlin J, Yang Z. Poxvirus-encoded decapping enzymes promote selective translation of viral mRNAs. PLoS Pathog 2020; 16:e1008926. [PMID: 33031446 PMCID: PMC7575113 DOI: 10.1371/journal.ppat.1008926] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 10/20/2020] [Accepted: 08/24/2020] [Indexed: 12/24/2022] Open
Abstract
Cellular decapping enzymes negatively regulate gene expression by removing the methylguanosine cap at the 5’ end of eukaryotic mRNA, rendering mRNA susceptible to degradation and repressing mRNA translation. Vaccinia virus (VACV), the prototype poxvirus, encodes two decapping enzymes, D9 and D10, that induce the degradation of both cellular and viral mRNAs. Using a genome-wide survey of translation efficiency, we analyzed vaccinia virus mRNAs in cells infected with wild type VACV and mutant VACVs with inactivated decapping enzymes. We found that VACV decapping enzymes are required for selective translation of viral post-replicative mRNAs (transcribed after viral DNA replication) independent of PKR- and RNase L-mediated translation repression. Further molecular characterization demonstrated that VACV decapping enzymes are necessary for efficient translation of mRNA with a 5'-poly(A) leader, which are present in all viral post-replicative mRNAs. Inactivation of D10 alone in VACV significantly impairs poly(A)-leader-mediated translation. Remarkably, D10 stimulates mRNA translation in the absence of VACV infection with a preference for RNA containing a 5’-poly(A) leader. We further revealed that VACV decapping enzymes are needed for 5’-poly(A) leader-mediated cap-independent translation enhancement during infection. Our findings identified a mechanism by which VACV mRNAs are selectively translated through subverting viral decapping enzymes to stimulate 5’-poly(A) leader-mediated translation. Decapping enzymes are encoded in eukaryotic cells and some viruses. Previous studies indicated that decapping enzymes are negative gene expression regulators by accelerating mRNA degradation and repressing translation. Surprisingly however, in this study we found that vaccinia virus (VACV) encoded-decapping enzymes, D9 and D10, are required to promote selective synthesis of viral proteins, although they are known to promote both cellular and viral mRNA degradation. We further showed that the unusual 5'-UTR of VACV mRNA, the 5'-poly(A) leader, confers an advantage to mRNA translation promoted by the decapping enzymes during vaccinia virus infection. Moreover, D9 and D10 are necessary for stimulating poly(A)-leader-mediated cap-independent translation enhancement during VACV infection. In the absence of VACV infection, D10 alone stimulates mRNA translation in a decapping activity-dependent manner, with a preference for mRNA that contains a poly(A) leader. The stimulation of mRNA translation by D10 is unique among decapping enzymes. Therefore, we identified a new mechanism to selectively synthesize VACV proteins through a coordination of viral mRNA 5’-UTR and virus-encoded decapping enzymes.
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Affiliation(s)
- Fernando Cantu
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Shuai Cao
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Candy Hernandez
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Pragyesh Dhungel
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Joshua Spradlin
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Zhilong Yang
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
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17
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Kluge F, Götze M, Wahle E. Establishment of 5'-3' interactions in mRNA independent of a continuous ribose-phosphate backbone. RNA (NEW YORK, N.Y.) 2020; 26:613-628. [PMID: 32111664 PMCID: PMC7161349 DOI: 10.1261/rna.073759.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/24/2020] [Indexed: 06/10/2023]
Abstract
Functions of eukaryotic mRNAs are characterized by intramolecular interactions between their ends. We have addressed the question whether 5' and 3' ends meet by diffusion-controlled encounter "through solution" or by a mechanism involving the RNA backbone. For this purpose, we used a translation system derived from Drosophila embryos that displays two types of 5'-3' interactions: Cap-dependent translation initiation is stimulated by the poly(A) tail and inhibited by Smaug recognition elements (SREs) in the 3' UTR. Chimeric RNAs were made consisting of one RNA molecule carrying a luciferase coding sequence and a second molecule containing SREs and a poly(A) tail; the two were connected via a protein linker. The poly(A) tail stimulated translation of such chimeras even when disruption of the RNA backbone was combined with an inversion of the 5'-3' polarity between the open reading frame and poly(A) segment. Stimulation by the poly(A) tail also decreased with increasing RNA length. Both observations suggest that contacts between the poly(A) tail and the 5' end are established through solution, independently of the RNA backbone. In the same chimeric constructs, SRE-dependent inhibition of translation was also insensitive to disruption of the RNA backbone. Thus, tracking of the backbone is not involved in the repression of cap-dependent initiation. However, SRE-dependent repression was insensitive to mRNA length, suggesting that the contact between the SREs in the 3' UTR and the 5' end of the RNA might be established in a manner that differs from the contact between the poly(A) tail and the cap.
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Affiliation(s)
- Florian Kluge
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Michael Götze
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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18
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Räsch F, Weber R, Izaurralde E, Igreja C. 4E-T-bound mRNAs are stored in a silenced and deadenylated form. Genes Dev 2020; 34:847-860. [PMID: 32354837 PMCID: PMC7263148 DOI: 10.1101/gad.336073.119] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/02/2020] [Indexed: 12/20/2022]
Abstract
Human 4E-T is an eIF4E-binding protein (4E-BP) present in processing (P)-bodies that represses translation and regulates decay of mRNAs destabilized by AU-rich elements and microRNAs (miRNAs). However, the underlying regulatory mechanisms are still unclear. Here, we show that upon mRNA binding 4E-T represses translation and promotes deadenylation via the recruitment of the CCR4-NOT deadenylase complex. The interaction with CCR4-NOT is mediated by previously uncharacterized sites in the middle region of 4E-T. Importantly, mRNA decapping and decay are inhibited by 4E-T and the deadenylated target is stored in a repressed form. Inhibition of mRNA decapping requires the interaction of 4E-T with the cap-binding proteins eIF4E/4EHP. We further show that regulation of decapping by 4E-T participates in mRNA repression by the miRNA effector protein TNRC6B and that 4E-T overexpression interferes with tristetraprolin (TTP)- and NOT1-mediated mRNA decay. Thus, we postulate that 4E-T modulates 5'-to-3' decay by swapping the fate of a deadenylated mRNA from complete degradation to storage. Our results provide insight into the mechanism of mRNA storage that controls localized translation and mRNA stability in P-bodies.
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Affiliation(s)
- Felix Räsch
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Ramona Weber
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Cátia Igreja
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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19
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Forrest ME, Pinkard O, Martin S, Sweet TJ, Hanson G, Coller J. Codon and amino acid content are associated with mRNA stability in mammalian cells. PLoS One 2020; 15:e0228730. [PMID: 32053646 PMCID: PMC7018022 DOI: 10.1371/journal.pone.0228730] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/21/2020] [Indexed: 12/31/2022] Open
Abstract
Messenger RNA (mRNA) degradation plays a critical role in regulating transcript levels in the cell and is a major control point for modulating gene expression. In yeast and other model organisms, codon identity is a powerful determinant of transcript stability, contributing broadly to impact half-lives. General principles governing mRNA stability are poorly understood in mammalian systems. Importantly, however, the degradation machinery is highly conserved, thus it seems logical that mammalian transcript half-lives would also be strongly influenced by coding determinants. Herein we characterize the contribution of coding sequence towards mRNA decay in human and Chinese Hamster Ovary cells. In agreement with previous studies, we observed that synonymous codon usage impacts mRNA stability in mammalian cells. Surprisingly, however, we also observe that the amino acid content of a gene is an additional determinant correlating with transcript stability. The impact of codon and amino acid identity on mRNA decay appears to be associated with underlying tRNA and intracellular amino acid concentrations. Accordingly, genes of similar physiological function appear to coordinate their mRNA stabilities in part through codon and amino acid content. Together, these results raise the possibility that intracellular tRNA and amino acid levels interplay to mediate coupling between translational elongation and mRNA degradation rate in mammals.
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Affiliation(s)
- Megan E. Forrest
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Otis Pinkard
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Sophie Martin
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Thomas J. Sweet
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Gavin Hanson
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jeff Coller
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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20
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Park H, Subramaniam AR. Inverted translational control of eukaryotic gene expression by ribosome collisions. PLoS Biol 2019; 17:e3000396. [PMID: 31532761 PMCID: PMC6750593 DOI: 10.1371/journal.pbio.3000396] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 08/05/2019] [Indexed: 11/19/2022] Open
Abstract
The canonical model of eukaryotic translation posits that efficient translation initiation increases protein expression and mRNA stability. Contrary to this model, we find that increasing initiation rate can decrease both protein expression and stability of certain mRNAs in the budding yeast Saccharomyces cerevisiae. These mRNAs encode a stretch of polybasic residues that cause ribosome stalling. Our computational modeling predicts that the observed decrease in gene expression at high initiation rates occurs when ribosome collisions at stalls stimulate abortive termination of the leading ribosome or cause endonucleolytic mRNA cleavage. Consistent with this prediction, the collision-associated quality-control factors Asc1 and Hel2 (orthologs of human RACK1 and ZNF598, respectively) decrease gene expression from stall-containing mRNAs only at high initiation rates. Remarkably, hundreds of S. cerevisiae mRNAs that contain ribosome stall sequences also exhibit lower translation efficiency. We propose that inefficient translation initiation allows these stall-containing endogenous mRNAs to escape collision-stimulated reduction in gene expression. Higher rates of translation counterintuitively lead to lower protein levels from eukaryotic mRNAs that encode ribosome stalls; modelling suggests that this occurs when ribosome collisions at stalls trigger abortive termination of the leading ribosome or cause endonucleolytic mRNA cleavage.
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Affiliation(s)
- Heungwon Park
- Basic Sciences Division and Computational Biology Section of Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Arvind R. Subramaniam
- Basic Sciences Division and Computational Biology Section of Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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21
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Hia F, Yang SF, Shichino Y, Yoshinaga M, Murakawa Y, Vandenbon A, Fukao A, Fujiwara T, Landthaler M, Natsume T, Adachi S, Iwasaki S, Takeuchi O. Codon bias confers stability to human mRNAs. EMBO Rep 2019; 20:e48220. [PMID: 31482640 DOI: 10.15252/embr.201948220] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 08/08/2019] [Accepted: 08/19/2019] [Indexed: 11/09/2022] Open
Abstract
Codon bias has been implicated as one of the major factors contributing to mRNA stability in several model organisms. However, the molecular mechanisms of codon bias on mRNA stability remain unclear in humans. Here, we show that human cells possess a mechanism to modulate RNA stability through a unique codon bias. Bioinformatics analysis showed that codons could be clustered into two distinct groups-codons with G or C at the third base position (GC3) and codons with either A or T at the third base position (AT3): the former stabilizing while the latter destabilizing mRNA. Quantification of codon bias showed that increased GC3-content entails proportionately higher GC-content. Through bioinformatics, ribosome profiling, and in vitro analysis, we show that decoupling the effects of codon bias reveals two modes of mRNA regulation, one GC3- and one GC-content dependent. Employing an immunoprecipitation-based strategy, we identify ILF2 and ILF3 as RNA-binding proteins that differentially regulate global mRNA abundances based on codon bias. Our results demonstrate that codon bias is a two-pronged system that governs mRNA abundance.
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Affiliation(s)
- Fabian Hia
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Sheng Fan Yang
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yuichi Shichino
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Japan
| | - Masanori Yoshinaga
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasuhiro Murakawa
- Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama, Japan.,RIKEN Preventive Medicine and Diagnosis Innovation Program, Yokohama, Japan
| | - Alexis Vandenbon
- Laboratory of Infection and Prevention, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Akira Fukao
- Laboratory of Biochemistry, Department of Pharmacy, Kindai University, Higashiosaka City, Japan
| | - Toshinobu Fujiwara
- Laboratory of Biochemistry, Department of Pharmacy, Kindai University, Higashiosaka City, Japan
| | - Markus Landthaler
- RNA Biology and Posttranscriptional Regulation, Max Delbrück Center for Molecular Medicine Berlin, Berlin Institute for Molecular Systems Biology, Berlin, Germany.,IRI Life Sciences, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tohru Natsume
- Molecular Profiling Research Center for Drug Discovery (molprof), National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Shungo Adachi
- Molecular Profiling Research Center for Drug Discovery (molprof), National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Shintaro Iwasaki
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Osamu Takeuchi
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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22
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Chang Y, Huh WK. Ksp1-dependent phosphorylation of eIF4G modulates post-transcriptional regulation of specific mRNAs under glucose deprivation conditions. Nucleic Acids Res 2019; 46:3047-3060. [PMID: 29438499 PMCID: PMC5888036 DOI: 10.1093/nar/gky097] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 02/05/2018] [Indexed: 12/31/2022] Open
Abstract
Post-transcriptional regulation is an important mechanism for modulating gene expression and is performed by numerous mRNA-binding proteins. To understand the mechanisms underlying post-transcriptional regulation, we investigated the phosphorylation status of 32 mRNA-binding proteins under glucose deprivation conditions in Saccharomyces cerevisiae. We identified 17 glucose-sensitive phosphoproteins and signal pathways implicated in their phosphorylation. Notably, phosphorylation of the eukaryotic translation initiation factor 4G (eIF4G) was regulated by both the Snf1/AMPK pathway and the target of rapamycin complex 1 (TORC1) pathway. The serine/threonine protein kinase Ksp1 has previously been suggested to be a downstream effector of TORC1, but its detailed function has rarely been discussed. We identified that Snf1/AMPK and TORC1 signalings converge on Ksp1, which phosphorylates eIF4G under glucose deprivation conditions. Ksp1-dependent phosphorylation of eIF4G regulates the degradation of specific mRNAs (e.g. glycolytic mRNAs and ribosomal protein mRNAs) under glucose deprivation conditions likely through the recruitment of Dhh1. Taken together, our results suggest that Ksp1 functions as a novel modulator of post-transcriptional regulation in yeast.
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Affiliation(s)
- Yeonji Chang
- Department of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Won-Ki Huh
- Department of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea.,Institute of Microbiology, Seoul National University, Seoul 08826, Republic of Korea
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23
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Sachdev R, Hondele M, Linsenmeier M, Vallotton P, Mugler CF, Arosio P, Weis K. Pat1 promotes processing body assembly by enhancing the phase separation of the DEAD-box ATPase Dhh1 and RNA. eLife 2019; 8:41415. [PMID: 30648970 PMCID: PMC6366900 DOI: 10.7554/elife.41415] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/15/2019] [Indexed: 12/24/2022] Open
Abstract
Processing bodies (PBs) are cytoplasmic mRNP granules that assemble via liquid-liquid phase separation and are implicated in the decay or storage of mRNAs. How PB assembly is regulated in cells remains unclear. Previously, we identified the ATPase activity of the DEAD-box protein Dhh1 as a key regulator of PB dynamics and demonstrated that Not1, an activator of the Dhh1 ATPase and member of the CCR4-NOT deadenylase complex inhibits PB assembly in vivo (Mugler et al., 2016). Here, we show that the PB component Pat1 antagonizes Not1 and promotes PB assembly via its direct interaction with Dhh1. Intriguingly, in vivo PB dynamics can be recapitulated in vitro, since Pat1 enhances the phase separation of Dhh1 and RNA into liquid droplets, whereas Not1 reverses Pat1-Dhh1-RNA condensation. Overall, our results uncover a function of Pat1 in promoting the multimerization of Dhh1 on mRNA, thereby aiding the assembly of large multivalent mRNP granules that are PBs.
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Affiliation(s)
| | | | | | | | - Christopher F Mugler
- ETH Zurich, Zurich, Switzerland.,University of California, Berkeley, Berkeley, United States
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24
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Adivarahan S, Zenklusen D. Lessons from (pre-)mRNA Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:247-284. [DOI: 10.1007/978-3-030-31434-7_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Vicens Q, Kieft JS, Rissland OS. Revisiting the Closed-Loop Model and the Nature of mRNA 5'-3' Communication. Mol Cell 2018; 72:805-812. [PMID: 30526871 PMCID: PMC6294470 DOI: 10.1016/j.molcel.2018.10.047] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/08/2018] [Accepted: 10/30/2018] [Indexed: 12/28/2022]
Abstract
Communication between the 5' and 3' ends of mature eukaryotic mRNAs lies at the heart of gene regulation, likely arising at the same time as the eukaryotic lineage itself. Our view of how and why it occurs has been shaped by elegant experiments that led to nearly universal acceptance of the "closed-loop model." However, new observations suggest that this classic model needs to be reexamined, revised, and expanded. Here, we address fundamental questions about the closed-loop model and discuss how a growing understanding of mRNA structure, dynamics, and intermolecular interactions presents new experimental opportunities. We anticipate that the application of emerging methods will lead to expanded models that include the role of intrinsic mRNA structure and quantitative dynamic descriptions of 5'-3' proximity linked to the functional status of an mRNA and will better reflect the messy realities of the crowded and rapidly changing cellular environment.
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Affiliation(s)
- Quentin Vicens
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA.
| | - Olivia S Rissland
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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26
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Chan LY, Mugler CF, Heinrich S, Vallotton P, Weis K. Non-invasive measurement of mRNA decay reveals translation initiation as the major determinant of mRNA stability. eLife 2018; 7:32536. [PMID: 30192227 PMCID: PMC6152797 DOI: 10.7554/elife.32536] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 08/13/2018] [Indexed: 12/15/2022] Open
Abstract
The cytoplasmic abundance of mRNAs is strictly controlled through a balance of production and degradation. Whereas the control of mRNA synthesis through transcription has been well characterized, less is known about the regulation of mRNA turnover, and a consensus model explaining the wide variations in mRNA decay rates remains elusive. Here, we combine non-invasive transcriptome-wide mRNA production and stability measurements with selective and acute perturbations to demonstrate that mRNA degradation is tightly coupled to the regulation of translation, and that a competition between translation initiation and mRNA decay -but not codon optimality or elongation- is the major determinant of mRNA stability in yeast. Our refined measurements also reveal a remarkably dynamic transcriptome with an average mRNA half-life of only 4.8 min - much shorter than previously thought. Furthermore, global mRNA destabilization by inhibition of translation initiation induces a dose-dependent formation of processing bodies in which mRNAs can decay over time.
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Affiliation(s)
- Leon Y Chan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Christopher F Mugler
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | | | | | - Karsten Weis
- Department of Biochemistry, ETH Zurich, Zurich, Switzerland
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27
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Abstract
Ribonucleic acid (RNA) homeostasis is dynamically modulated in response to changing physiological conditions. Tight regulation of RNA abundance through both transcription and degradation determines the amount, timing, and location of protein translation. This balance is of particular importance in neurons, which are among the most metabolically active and morphologically complex cells in the body. As a result, any disruptions in RNA degradation can have dramatic consequences for neuronal health. In this chapter, we will first discuss mechanisms of RNA stabilization and decay. We will then explore how the disruption of these pathways can lead to neurodegenerative disease.
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28
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Synthetic mRNA with Superior Properties that Mimics the Intracellular Fates of Natural Histone mRNA. Methods Mol Biol 2017; 1428:93-114. [PMID: 27236794 DOI: 10.1007/978-1-4939-3625-0_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Since DNA and histone levels must be closely balanced for cell survival, histone expressions are highly regulated. The regulation of replication-dependent histone expression is mainly achieved at the mRNA level, as the mRNAs are rapidly removed when DNA replication is inhibited during S-phase. Histone mRNA degradation initiates with addition of multiple uridines (oligouridylation) following the 3' stem-loop (SL) catalyzed by terminal uridyltransferase (TUTase). Previous studies showed that histone mRNA degradation occurs through both 5' → 3' and 3' → 5' processes, but the relative contributions are difficult to dissect due to lack of established protocols. The translational efficiency and stability of synthetic mRNA in both cultured cells and whole animals can be improved by structural modifications at the both 5' and 3' termini. In this chapter, we present methods of utilizing modified cap dinucleotide analogs to block 5' → 3' degradation of a reporter mRNA containing canonical histone mRNA 3' SL and monitoring how oligouridylation and 3' → 5' degradation occur. Protocols are presented for synthesis of reporter mRNA containing the histone 3' SL and modified cap analogs, monitoring mRNA stability and unidirectional degradation either from 5' or 3' termini, and detection of oligo(U) tracts from degradation products by either traditional or deep sequencing.
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29
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Rissland OS, Subtelny AO, Wang M, Lugowski A, Nicholson B, Laver JD, Sidhu SS, Smibert CA, Lipshitz HD, Bartel DP. The influence of microRNAs and poly(A) tail length on endogenous mRNA-protein complexes. Genome Biol 2017; 18:211. [PMID: 29089021 PMCID: PMC5664449 DOI: 10.1186/s13059-017-1330-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 09/29/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND All mRNAs are bound in vivo by proteins to form mRNA-protein complexes (mRNPs), but changes in the composition of mRNPs during posttranscriptional regulation remain largely unexplored. Here, we have analyzed, on a transcriptome-wide scale, how microRNA-mediated repression modulates the associations of the core mRNP components eIF4E, eIF4G, and PABP and of the decay factor DDX6 in human cells. RESULTS Despite the transient nature of repressed intermediates, we detect significant changes in mRNP composition, marked by dissociation of eIF4G and PABP, and by recruitment of DDX6. Furthermore, although poly(A)-tail length has been considered critical in post-transcriptional regulation, differences in steady-state tail length explain little of the variation in either PABP association or mRNP organization more generally. Instead, relative occupancy of core components correlates best with gene expression. CONCLUSIONS These results indicate that posttranscriptional regulatory factors, such as microRNAs, influence the associations of PABP and other core factors, and do so without substantially affecting steady-state tail length.
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Affiliation(s)
- Olivia S Rissland
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA. .,Howard Hughes Medical Institute, Cambridge, MA, 02142, USA. .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Present address: Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA.
| | - Alexander O Subtelny
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA.,Howard Hughes Medical Institute, Cambridge, MA, 02142, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Miranda Wang
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Andrew Lugowski
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Beth Nicholson
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - John D Laver
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Sachdev S Sidhu
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Craig A Smibert
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - David P Bartel
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA. .,Howard Hughes Medical Institute, Cambridge, MA, 02142, USA. .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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30
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Wang M, Ly M, Lugowski A, Laver JD, Lipshitz HD, Smibert CA, Rissland OS. ME31B globally represses maternal mRNAs by two distinct mechanisms during the Drosophila maternal-to-zygotic transition. eLife 2017; 6:27891. [PMID: 28875934 PMCID: PMC5779226 DOI: 10.7554/elife.27891] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 09/04/2017] [Indexed: 12/27/2022] Open
Abstract
In animal embryos, control of development is passed from exclusively maternal gene products to those encoded by the embryonic genome in a process referred to as the maternal-to-zygotic transition (MZT). We show that the RNA-binding protein, ME31B, binds to and represses the expression of thousands of maternal mRNAs during the Drosophila MZT. However, ME31B carries out repression in different ways during different phases of the MZT. Early, it represses translation while, later, its binding leads to mRNA destruction, most likely as a consequence of translational repression in the context of robust mRNA decay. In a process dependent on the PNG kinase, levels of ME31B and its partners, Cup and Trailer Hitch (TRAL), decrease by over 10-fold during the MZT, leading to a change in the composition of mRNA-protein complexes. We propose that ME31B is a global repressor whose regulatory impact changes based on its biological context.
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Affiliation(s)
- Miranda Wang
- Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Michael Ly
- Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Andrew Lugowski
- Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - John D Laver
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Craig A Smibert
- Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Olivia S Rissland
- Molecular Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, United States.,RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, United States
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31
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Das S, Sarkar D, Das B. The interplay between transcription and mRNA degradation in Saccharomyces cerevisiae. MICROBIAL CELL 2017; 4:212-228. [PMID: 28706937 PMCID: PMC5507684 DOI: 10.15698/mic2017.07.580] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The cellular transcriptome is shaped by both the rates of mRNA synthesis in the nucleus and mRNA degradation in the cytoplasm under a specified condition. The last decade witnessed an exciting development in the field of post-transcriptional regulation of gene expression which underscored a strong functional coupling between the transcription and mRNA degradation. The functional integration is principally mediated by a group of specialized promoters and transcription factors that govern the stability of their cognate transcripts by “marking” them with a specific factor termed “coordinator.” The “mark” carried by the message is later decoded in the cytoplasm which involves the stimulation of one or more mRNA-decay factors, either directly by the “coordinator” itself or in an indirect manner. Activation of the decay factor(s), in turn, leads to the alteration of the stability of the marked message in a selective fashion. Thus, the integration between mRNA synthesis and decay plays a potentially significant role to shape appropriate gene expression profiles during cell cycle progression, cell division, cellular differentiation and proliferation, stress, immune and inflammatory responses, and may enhance the rate of biological evolution.
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Affiliation(s)
- Subhadeep Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Debasish Sarkar
- Present Address: Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12201-2002, USA
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
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32
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When mRNA translation meets decay. Biochem Soc Trans 2017; 45:339-351. [DOI: 10.1042/bst20160243] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 12/19/2016] [Accepted: 01/11/2017] [Indexed: 12/26/2022]
Abstract
Messenger RNA (mRNA) translation and mRNA degradation are important determinants of protein output, and they are interconnected. Previously, it was thought that translation of an mRNA, as a rule, prevents its degradation. mRNA surveillance mechanisms, which degrade mRNAs as a consequence of their translation, were considered to be exceptions to this rule. Recently, however, it has become clear that many mRNAs are degraded co-translationally, and it has emerged that codon choice, by influencing the rate of ribosome elongation, affects the rate of mRNA decay. In this review, we discuss the links between translation and mRNA stability, with an emphasis on emerging data suggesting that codon optimality may regulate mRNA degradation.
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33
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Li J, Wang W, He Y, Li Y, Yan EZ, Zhang K, Irvine DJ, Hammond PT. Structurally Programmed Assembly of Translation Initiation Nanoplex for Superior mRNA Delivery. ACS NANO 2017; 11:2531-2544. [PMID: 28157292 PMCID: PMC5629916 DOI: 10.1021/acsnano.6b08447] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Messenger RNA (mRNA) represents a promising class of nucleic-acid-based therapeutics. While numerous nanocarriers have been developed for mRNA delivery, the inherent labile nature of mRNA results in a very low transfection efficiency and poor expression of desired protein. Here we preassemble the mRNA translation initiation structure through an inherent molecular recognition between 7-methylguanosine (m7G)-capped mRNA and eukaryotic initiation factor 4E (eIF4E) protein to form ribonucleoproteins (RNPs), thereby mimicking the first step of protein synthesis inside cells. Subsequent electrostatic stabilization of RNPs with structurally tunable cationic carriers leads to nanosized complexes (nanoplexes), which elicit high levels of mRNA transfection in different cell types by enhancing intracellular mRNA stability and protein synthesis. By investigating a family of synthetic polypeptides bearing different side group arrangements of cationic charge, we find that the molecular structure modulates the nanoscale distance between the mRNA strand and the eIF4E protein inside the nanoplex, which directly impacts the enhancement of mRNA transfection. To demonstrate the biomedical potential of this approach, we use this approach to introduce mRNA/eIF4E nanoplexes to murine dendritic cells, resulting in increased activation of cytotoxic CD8 T cells ex vivo. More importantly, eIF4E enhances gene expression in lungs following a systemic delivery of luciferase mRNA/eIF4E in mice. Collectively, this bioinspired molecular assembly method could lead to a new paradigm of gene delivery.
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Affiliation(s)
- Jiahe Li
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Wade Wang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Yanpu He
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Yingzhong Li
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Emily Z. Yan
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Ketian Zhang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Darrell J. Irvine
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Paula T. Hammond
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
- Correspondence: David H. Koch Professor in Engineering, Bayer Chair Professor of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States.
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34
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Łabno A, Tomecki R, Dziembowski A. Cytoplasmic RNA decay pathways - Enzymes and mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:3125-3147. [PMID: 27713097 DOI: 10.1016/j.bbamcr.2016.09.023] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 12/14/2022]
Abstract
RNA decay plays a crucial role in post-transcriptional regulation of gene expression. Work conducted over the last decades has defined the major mRNA decay pathways, as well as enzymes and their cofactors responsible for these processes. In contrast, our knowledge of the mechanisms of degradation of non-protein coding RNA species is more fragmentary. This review is focused on the cytoplasmic pathways of mRNA and ncRNA degradation in eukaryotes. The major 3' to 5' and 5' to 3' mRNA decay pathways are described with emphasis on the mechanisms of their activation by the deprotection of RNA ends. More recently discovered 3'-end modifications such as uridylation, and their relevance to cytoplasmic mRNA decay in various model organisms, are also discussed. Finally, we provide up-to-date findings concerning various pathways of non-coding RNA decay in the cytoplasm.
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Affiliation(s)
- Anna Łabno
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Rafał Tomecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland.
| | - Andrzej Dziembowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland.
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35
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Rissland OS. The organization and regulation of mRNA-protein complexes. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27324829 PMCID: PMC5213448 DOI: 10.1002/wrna.1369] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 12/21/2022]
Abstract
In a eukaryotic cell, each messenger RNA (mRNA) is bound to a variety of proteins to form an mRNA-protein complex (mRNP). Together, these proteins impact nearly every step in the life cycle of an mRNA and are critical for the proper control of gene expression. In the cytoplasm, for instance, mRNPs affect mRNA translatability and stability and provide regulation of specific transcripts as well as global, transcriptome-wide control. mRNPs are complex, diverse, and dynamic, and so they have been a challenge to understand. But the advent of high-throughput sequencing technology has heralded a new era in the study of mRNPs. Here, I will discuss general principles of cytoplasmic mRNP organization and regulation. Using microRNA-mediated repression as a case study, I will focus on common themes in mRNPs and highlight the interplay between mRNP composition and posttranscriptional regulation. mRNPs are an important control point in regulating gene expression, and while the study of these fascinating complexes presents remaining challenges, recent advances provide a critical lens for deciphering gene regulation. WIREs RNA 2017, 8:e1369. doi: 10.1002/wrna.1369 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Olivia S Rissland
- Molecular Structure and Function Program, The Hospital for Sick Children Research Institute, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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36
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Chuang TW, Lee KM, Lou YC, Lu CC, Tarn WY. A Point Mutation in the Exon Junction Complex Factor Y14 Disrupts Its Function in mRNA Cap Binding and Translation Enhancement. J Biol Chem 2016; 291:8565-74. [PMID: 26887951 DOI: 10.1074/jbc.m115.704544] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Indexed: 12/17/2022] Open
Abstract
Eukaryotic mRNA biogenesis involves a series of interconnected steps mediated by RNA-binding proteins. The exon junction complex core protein Y14 is required for nonsense-mediated mRNA decay (NMD) and promotes translation. Moreover, Y14 binds the cap structure of mRNAs and inhibits the activity of the decapping enzyme Dcp2. In this report, we show that an evolutionarily conserved tryptophan residue (Trp-73) of Y14 is critical for its binding to the mRNA cap structure. A Trp-73 mutant (W73V) bound weakly to mRNAs and failed to protect them from degradation. However, this mutant could still interact with the NMD and mRNA degradation factors and retained partial NMD activity. In addition, we found that the W73V mutant could not interact with translation initiation factors. Overexpression of W73V suppressed reporter mRNA translation in vitro and in vivo and reduced the level of a set of nascent proteins. These results reveal a residue of Y14 that confers cap-binding activity and is essential for Y14-mediated enhancement of translation. Finally, we demonstrated that Y14 may selectively and differentially modulate protein biosynthesis.
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Affiliation(s)
- Tzu-Wei Chuang
- From the Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Kuo-Ming Lee
- From the Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Yuan-Chao Lou
- From the Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Chia-Chen Lu
- From the Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Woan-Yuh Tarn
- From the Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
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37
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Jang C, Lahens NF, Hogenesch JB, Sehgal A. Ribosome profiling reveals an important role for translational control in circadian gene expression. Genome Res 2015; 25:1836-47. [PMID: 26338483 PMCID: PMC4665005 DOI: 10.1101/gr.191296.115] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 09/02/2015] [Indexed: 01/30/2023]
Abstract
Physiological and behavioral circadian rhythms are driven by a conserved transcriptional/translational negative feedback loop in mammals. Although most core clock factors are transcription factors, post-transcriptional control introduces delays that are critical for circadian oscillations. Little work has been done on circadian regulation of translation, so to address this deficit we conducted ribosome profiling experiments in a human cell model for an autonomous clock. We found that most rhythmic gene expression occurs with little delay between transcription and translation, suggesting that the lag in the accumulation of some clock proteins relative to their mRNAs does not arise from regulated translation. Nevertheless, we found that translation occurs in a circadian fashion for many genes, sometimes imposing an additional level of control on rhythmically expressed mRNAs and, in other cases, conferring rhythms on noncycling mRNAs. Most cyclically transcribed RNAs are translated at one of two major times in a 24-h day, while rhythmic translation of most noncyclic RNAs is phased to a single time of day. Unexpectedly, we found that the clock also regulates the formation of cytoplasmic processing (P) bodies, which control the fate of mRNAs, suggesting circadian coordination of mRNA metabolism and translation.
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Affiliation(s)
- Christopher Jang
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Nicholas F Lahens
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - John B Hogenesch
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Amita Sehgal
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA; Howard Hughes Medical Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
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38
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Preissler S, Reuther J, Koch M, Scior A, Bruderek M, Frickey T, Deuerling E. Not4-dependent translational repression is important for cellular protein homeostasis in yeast. EMBO J 2015; 34:1905-24. [PMID: 25971775 DOI: 10.15252/embj.201490194] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 04/12/2015] [Indexed: 11/09/2022] Open
Abstract
Translation of aberrant or problematic mRNAs can cause ribosome stalling which leads to the production of truncated or defective proteins. Therefore, cells evolved cotranslational quality control mechanisms that eliminate these transcripts and target arrested nascent polypeptides for proteasomal degradation. Here we show that Not4, which is part of the multifunctional Ccr4-Not complex in yeast, associates with polysomes and contributes to the negative regulation of protein synthesis. Not4 is involved in translational repression of transcripts that cause transient ribosome stalling. The absence of Not4 affected global translational repression upon nutrient withdrawal, enhanced the expression of arrested nascent polypeptides and caused constitutive protein folding stress and aggregation. Similar defects were observed in cells with impaired mRNA decapping protein function and in cells lacking the mRNA decapping activator and translational repressor Dhh1. The results suggest a role for Not4 together with components of the decapping machinery in the regulation of protein expression on the mRNA level and emphasize the importance of translational repression for the maintenance of proteome integrity.
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Affiliation(s)
- Steffen Preissler
- Molecular Microbiology, University of Konstanz, Konstanz, Germany Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
| | - Julia Reuther
- Molecular Microbiology, University of Konstanz, Konstanz, Germany Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
| | - Miriam Koch
- Molecular Microbiology, University of Konstanz, Konstanz, Germany Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
| | - Annika Scior
- Molecular Microbiology, University of Konstanz, Konstanz, Germany Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
| | - Michael Bruderek
- Molecular Microbiology, University of Konstanz, Konstanz, Germany
| | - Tancred Frickey
- Applied Bioinformatics, University of Konstanz, Konstanz, Germany
| | - Elke Deuerling
- Molecular Microbiology, University of Konstanz, Konstanz, Germany
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39
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General and MicroRNA-Mediated mRNA Degradation Occurs on Ribosome Complexes in Drosophila Cells. Mol Cell Biol 2015; 35:2309-20. [PMID: 25918245 DOI: 10.1128/mcb.01346-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 04/19/2015] [Indexed: 01/08/2023] Open
Abstract
The translation and degradation of mRNAs are two key steps in gene expression that are highly regulated and targeted by many factors, including microRNAs (miRNAs). While it is well established that translation and mRNA degradation are tightly coupled, it is still not entirely clear where in the cell mRNA degradation takes place. In this study, we investigated the possibility of mRNA degradation on the ribosome in Drosophila cells. Using polysome profiles and ribosome affinity purification, we could demonstrate the copurification of various deadenylation and decapping factors with ribosome complexes. Also, AGO1 and GW182, two key factors in the miRNA-mediated mRNA degradation pathway, were associated with ribosome complexes. Their copurification was dependent on intact mRNAs, suggesting the association of these factors with the mRNA rather than the ribosome itself. Furthermore, we isolated decapped mRNA degradation intermediates from ribosome complexes and performed high-throughput sequencing analysis. Interestingly, 93% of the decapped mRNA fragments (approximately 12,000) could be detected at the same relative abundance on ribosome complexes and in cell lysates. In summary, our findings strongly indicate the association of the majority of bulk mRNAs as well as mRNAs targeted by miRNAs with the ribosome during their degradation.
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40
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Raju KK, Natarajan S, Kumar NS, Kumar DA, NM R. Role of cytoplasmic deadenylation and mRNA decay factors in yeast apoptosis. FEMS Yeast Res 2015; 15:fou006. [DOI: 10.1093/femsyr/fou006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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41
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Melemedjian OK, Khoutorsky A. Translational control of chronic pain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:185-213. [PMID: 25744674 DOI: 10.1016/bs.pmbts.2014.11.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pain is a crucial physiological response to injury and pathologies. The development and maintenance of pain requires the expression of novel genes. The expression of such genes occurs in highly regulated and orchestrated manner where protein translation provides an exquisite temporal and spatial fidelity within the axons and dendrites of neurons. Signaling pathways that regulate local translation are activated by cytokines, neurotrophic factors, or neurotransmitters, which are released either due to tissue damage or neuronal activity. In recent years, the ERK and mTOR pathways have been demonstrated to be central in regulating local translation in neurons of both the peripheral and central nervous systems in diverse models of chronic pain. The ERK and mTOR pathways converge onto the cap-dependent translational machinery that regulates genes essential for the development of nociceptive sensitization. Moreover, inhibition of these pathways has proved to be effective in normalizing the biochemical changes and the associated pain in various preclinical models.
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Affiliation(s)
- Ohannes K Melemedjian
- Department of Neural and Pain Sciences, School of Dentistry, University of Maryland, Baltimore, Maryland, USA.
| | - Arkady Khoutorsky
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montréal, Quebec, Canada
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42
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Taverniti V, Séraphin B. Elimination of cap structures generated by mRNA decay involves the new scavenger mRNA decapping enzyme Aph1/FHIT together with DcpS. Nucleic Acids Res 2014; 43:482-92. [PMID: 25432955 PMCID: PMC4288156 DOI: 10.1093/nar/gku1251] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Eukaryotic 5' mRNA cap structures participate to the post-transcriptional control of gene expression before being released by the two main mRNA decay pathways. In the 3'-5' pathway, the exosome generates free cap dinucleotides (m7GpppN) or capped oligoribonucleotides that are hydrolyzed by the Scavenger Decapping Enzyme (DcpS) forming m7GMP. In the 5'-3' pathway, the decapping enzyme Dcp2 generates m7GDP. We investigated the fate of m7GDP and m7GpppN produced by RNA decay in extracts and cells. This defined a pathway involving DcpS, NTPs and the nucleoside diphosphate kinase for m7GDP elimination. Interestingly, we identified and characterized in vitro and in vivo a new scavenger decapping enzyme involved in m7GpppN degradation. We show that activities mediating cap elimination identified in yeast are essentially conserved in human. Their alteration may contribute to pathologies, possibly through the interference of cap (di)nucleotide with cellular function.
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Affiliation(s)
- Valerio Taverniti
- Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de Recherche Scientifique (CNRS) UMR 7104/Institut National de Santé et de Recherche Médicale (INSERM) U964/Université de Strasbourg, 67404 Illkirch, France
| | - Bertrand Séraphin
- Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de Recherche Scientifique (CNRS) UMR 7104/Institut National de Santé et de Recherche Médicale (INSERM) U964/Université de Strasbourg, 67404 Illkirch, France
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Chowdhury A, Kalurupalle S, Tharun S. Pat1 contributes to the RNA binding activity of the Lsm1-7-Pat1 complex. RNA (NEW YORK, N.Y.) 2014; 20:1465-75. [PMID: 25035297 PMCID: PMC4138329 DOI: 10.1261/rna.045252.114] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/03/2014] [Indexed: 05/20/2023]
Abstract
A major mRNA decay pathway in eukaryotes is initiated by deadenylation followed by decapping of the oligoadenylated mRNAs and subsequent 5'-to-3' exonucleolytic degradation of the capless mRNA. In this pathway, decapping is a rate-limiting step that requires the hetero-octameric Lsm1-7-Pat1 complex to occur at normal rates in vivo. This complex is made up of the seven Sm-like proteins, Lsm1 through Lsm7, and the Pat1 protein. It binds RNA and has a unique binding preference for oligoadenylated RNAs over polyadenylated RNAs. Such binding ability is crucial for its mRNA decay function in vivo. In order to determine the contribution of Pat1 to the function of the Lsm1-7-Pat1 complex, we compared the RNA binding properties of the Lsm1-7 complex purified from pat1Δ cells and purified Pat1 fragments with that of the wild-type Lsm1-7-Pat1 complex. Our studies revealed that both the Lsm1-7 complex and purified Pat1 fragments have very low RNA binding activity and are impaired in the ability to recognize the oligo(A) tail on the RNA. However, reconstitution of the Lsm1-7-Pat1 complex from these components restored these abilities. We also observed that Pat1 directly contacts RNA in the context of the Lsm1-7-Pat1 complex. These studies suggest that the unique RNA binding properties and the mRNA decay function of the Lsm1-7-Pat1 complex involve cooperation of residues from both Pat1 and the Lsm1-7 ring. Finally our studies also revealed that the middle domain of Pat1 is essential for the interaction of Pat1 with the Lsm1-7 complex in vivo.
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Affiliation(s)
- Ashis Chowdhury
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
| | - Swathi Kalurupalle
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
| | - Sundaresan Tharun
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
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44
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Huch S, Nissan T. Interrelations between translation and general mRNA degradation in yeast. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:747-63. [PMID: 24944158 PMCID: PMC4285117 DOI: 10.1002/wrna.1244] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 04/28/2014] [Accepted: 05/02/2014] [Indexed: 12/31/2022]
Abstract
Messenger RNA (mRNA) degradation is an important element of gene expression that can be modulated by alterations in translation, such as reductions in initiation or elongation rates. Reducing translation initiation strongly affects mRNA degradation by driving mRNA toward the assembly of a decapping complex, leading to decapping. While mRNA stability decreases as a consequence of translational inhibition, in apparent contradiction several external stresses both inhibit translation initiation and stabilize mRNA. A key difference in these processes is that stresses induce multiple responses, one of which stabilizes mRNAs at the initial and rate-limiting step of general mRNA decay. Because this increase in mRNA stability is directly induced by stress, it is independent of the translational effects of stress, which provide the cell with an opportunity to assess its response to changing environmental conditions. After assessment, the cell can store mRNAs, reinitiate their translation or, alternatively, embark on a program of enhanced mRNA decay en masse. Finally, recent results suggest that mRNA decay is not limited to non-translating messages and can occur when ribosomes are not initiating but are still elongating on mRNA. This review will discuss the models for the mechanisms of these processes and recent developments in understanding the relationship between translation and general mRNA degradation, with a focus on yeast as a model system. How to cite this article: WIREs RNA 2014, 5:747–763. doi: 10.1002/wrna.1244
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Affiliation(s)
- Susanne Huch
- Department of Molecular Biology, Umeå University, Umeå, Sweden
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45
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Abstract
The 7mG (7-methylguanosine cap) formed on mRNA is fundamental to eukaryotic gene expression. Protein complexes recruited to 7mG mediate key processing events throughout the lifetime of the transcript. One of the most important mediators of 7mG functions is CBC (cap-binding complex). CBC has a key role in several gene expression mechanisms, including transcription, splicing, transcript export and translation. Gene expression can be regulated by signalling pathways which influence CBC function. The aim of the present review is to discuss the mechanisms by which CBC mediates and co-ordinates multiple gene expression events.
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46
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Gonatopoulos-Pournatzis T, Cowling VH. Cap-binding complex (CBC). Biochem J 2014. [PMID: 24354960 DOI: 10.1042/bj2013121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The 7mG (7-methylguanosine cap) formed on mRNA is fundamental to eukaryotic gene expression. Protein complexes recruited to 7mG mediate key processing events throughout the lifetime of the transcript. One of the most important mediators of 7mG functions is CBC (cap-binding complex). CBC has a key role in several gene expression mechanisms, including transcription, splicing, transcript export and translation. Gene expression can be regulated by signalling pathways which influence CBC function. The aim of the present review is to discuss the mechanisms by which CBC mediates and co-ordinates multiple gene expression events.
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Affiliation(s)
| | - Victoria H Cowling
- *MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K
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47
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Abstract
The process of cell growth depends on a complex co-ordinated programme of macromolecular synthesis that can be tuned to environmental constraints. In eukaryotes, the mTOR [mammalian (or mechanistic) target of rapamycin] signalling pathway is a master regulator of this process, in part by regulating mRNA translation through control of the eIF4F (eukaryotic initiation factor 4F) initiation complex. The present review discusses the role of this relationship in mTOR-regulated gene expression, and its contribution to phenotypes associated with deregulated mTOR signalling, such as cancer.
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48
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Melemedjian OK, Mejia GL, Lepow TS, Zoph OK, Price TJ. Bidirectional regulation of P body formation mediated by eIF4F complex formation in sensory neurons. Neurosci Lett 2013; 563:169-74. [PMID: 24080374 DOI: 10.1016/j.neulet.2013.09.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 09/10/2013] [Accepted: 09/14/2013] [Indexed: 12/17/2022]
Abstract
Processing (P) bodies are RNA granules that comprise key cellular sites for the metabolism of mRNAs. In certain cells, including neurons, these RNA granules may also play an important role in storage of mRNAs in a translationally dormant state. Utilizing nerve growth factor (NGF) and interleukin 6 (IL6), which stimulate cap-dependent translation in sensory neurons, and adenosine monophosphate activated protein kinase (AMPK) activators, which inhibit cap-dependent translation, we have tested the hypothesis that cap-dependent translation is linked to P body formation in mammalian sensory neurons. Treatment with NGF and IL6 decreases, whereas metformin increases biochemical association of the P body marker and translational repressor/decapping activator Rck/p54/dhh1 with the 5'-mRNA-cap suggesting an ordered assembly of P bodies. Likewise, diverse AMPK activators enhance P body formation while NGF and IL6 decrease P bodies in sensory neurons. This bidirectional P body plasticity readily occurs in the axonal compartment of these neurons. These studies indicate that P body formation is intricately linked to cap-dependent translation in mammalian sensory neurons suggesting an important role for these organelles in the regulation of mRNA metabolism in the adult PNS.
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Affiliation(s)
| | - Galo L Mejia
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States.
| | - Talya S Lepow
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States.
| | - Olivia K Zoph
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States.
| | - Theodore J Price
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States.
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Nishihara T, Zekri L, Braun JE, Izaurralde E. miRISC recruits decapping factors to miRNA targets to enhance their degradation. Nucleic Acids Res 2013; 41:8692-705. [PMID: 23863838 PMCID: PMC3794582 DOI: 10.1093/nar/gkt619] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
MicroRNA (miRNA)-induced silencing complexes (miRISCs) repress translation and promote degradation of miRNA targets. Target degradation occurs through the 5′-to-3′ messenger RNA (mRNA) decay pathway, wherein, after shortening of the mRNA poly(A) tail, the removal of the 5′ cap structure by decapping triggers irreversible decay of the mRNA body. Here, we demonstrate that miRISC enhances the association of the decapping activators DCP1, Me31B and HPat with deadenylated miRNA targets that accumulate when decapping is blocked. DCP1 and Me31B recruitment by miRISC occurs before the completion of deadenylation. Remarkably, miRISC recruits DCP1, Me31B and HPat to engineered miRNA targets transcribed by RNA polymerase III, which lack a cap structure, a protein-coding region and a poly(A) tail. Furthermore, miRISC can trigger decapping and the subsequent degradation of mRNA targets independently of ongoing deadenylation. Thus, miRISC increases the local concentration of the decapping machinery on miRNA targets to facilitate decapping and irreversibly shut down their translation.
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Affiliation(s)
- Tadashi Nishihara
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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