1
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Weber R, Chang CT. Human DDX6 regulates translation and decay of inefficiently translated mRNAs. eLife 2024; 13:RP92426. [PMID: 38989862 PMCID: PMC11239181 DOI: 10.7554/elife.92426] [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] [Indexed: 07/12/2024] Open
Abstract
Recent findings indicate that the translation elongation rate influences mRNA stability. One of the factors that has been implicated in this link between mRNA decay and translation speed is the yeast DEAD-box helicase Dhh1p. Here, we demonstrated that the human ortholog of Dhh1p, DDX6, triggers the deadenylation-dependent decay of inefficiently translated mRNAs in human cells. DDX6 interacts with the ribosome through the Phe-Asp-Phe (FDF) motif in its RecA2 domain. Furthermore, RecA2-mediated interactions and ATPase activity are both required for DDX6 to destabilize inefficiently translated mRNAs. Using ribosome profiling and RNA sequencing, we identified two classes of endogenous mRNAs that are regulated in a DDX6-dependent manner. The identified targets are either translationally regulated or regulated at the steady-state-level and either exhibit signatures of poor overall translation or of locally reduced ribosome translocation rates. Transferring the identified sequence stretches into a reporter mRNA caused translation- and DDX6-dependent degradation of the reporter mRNA. In summary, these results identify DDX6 as a crucial regulator of mRNA translation and decay triggered by slow ribosome movement and provide insights into the mechanism by which DDX6 destabilizes inefficiently translated mRNAs.
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Affiliation(s)
- Ramona Weber
- Department of Biochemistry, Max Planck Institute for Developmental BiologyTübingenGermany
- Institute for Regenerative Medicine (IREM), University of ZurichZurichSwitzerland
| | - Chung-Te Chang
- Department of Biochemistry, Max Planck Institute for Developmental BiologyTübingenGermany
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung UniversityTaipei CityTaiwan
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2
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Ripin N, Macedo de Vasconcelos L, Ugay DA, Parker R. DDX6 modulates P-body and stress granule assembly, composition, and docking. J Cell Biol 2024; 223:e202306022. [PMID: 38536035 PMCID: PMC10978804 DOI: 10.1083/jcb.202306022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 12/20/2023] [Accepted: 03/04/2024] [Indexed: 04/01/2024] Open
Abstract
Stress granules and P-bodies are ribonucleoprotein (RNP) granules that accumulate during the stress response due to the condensation of untranslating mRNPs. Stress granules form in part by intermolecular RNA-RNA interactions and can be limited by components of the RNA chaperone network, which inhibits RNA-driven aggregation. Herein, we demonstrate that the DEAD-box helicase DDX6, a P-body component, can also limit the formation of stress granules, independent of the formation of P-bodies. In an ATPase, RNA-binding dependent manner, DDX6 limits the partitioning of itself and other RNPs into stress granules. When P-bodies are limited, proteins that normally partition between stress granules and P-bodies show increased accumulation within stress granules. Moreover, we show that loss of DDX6, 4E-T, and DCP1A increases P-body docking with stress granules, which depends on CNOT1 and PAT1B. Taken together, these observations identify a new role for DDX6 in limiting stress granules and demonstrate that P-body components can influence stress granule composition and docking with P-bodies.
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Affiliation(s)
- Nina Ripin
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | | | - Daniella A. Ugay
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
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3
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Gao M. Me31B: a key repressor in germline regulation and beyond. Biosci Rep 2024; 44:BSR20231769. [PMID: 38606619 PMCID: PMC11065648 DOI: 10.1042/bsr20231769] [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: 02/05/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 04/13/2024] Open
Abstract
Maternally Expressed at 31B (Me31B), an evolutionarily conserved ATP-dependent RNA helicase, plays an important role in the development of the germline across diverse animal species. Its cellular functionality has been posited as a translational repressor, participating in various RNA metabolism pathways to intricately regulate the spatiotemporal expression of RNAs. Despite its evident significance, the precise role and mechanistic underpinnings of Me31B remain insufficiently understood. This article endeavors to comprehensively review historic and recent research on Me31B, distill the major findings, discern generalizable patterns in Me31B's functions across different research contexts, and provide insights into its fundamental role and mechanism of action. The primary focus of this article centers on elucidating the role of Drosophila Me31B within the germline, while concurrently delving into pertinent research on its orthologs within other species and cellular systems.
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Affiliation(s)
- Ming Gao
- Biology Department, Indiana University Northwest, Gary, IN, U.S.A
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4
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He F, Jacobson A. Eukaryotic mRNA decapping factors: molecular mechanisms and activity. FEBS J 2023; 290:5057-5085. [PMID: 36098474 PMCID: PMC10008757 DOI: 10.1111/febs.16626] [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: 06/30/2022] [Revised: 08/11/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
Decapping is the enzymatic removal of 5' cap structures from mRNAs in eukaryotic cells. Cap structures normally enhance mRNA translation and stability, and their excision commits an mRNA to complete 5'-3' exoribonucleolytic digestion and generally ends the physical and functional cellular presence of the mRNA. Decapping plays a pivotal role in eukaryotic cytoplasmic mRNA turnover and is a critical and highly regulated event in multiple 5'-3' mRNA decay pathways, including general 5'-3' decay, nonsense-mediated mRNA decay (NMD), AU-rich element-mediated mRNA decay, microRNA-mediated gene silencing, and targeted transcript-specific mRNA decay. In the yeast Saccharomyces cerevisiae, mRNA decapping is carried out by a single Dcp1-Dcp2 decapping enzyme in concert with the accessory activities of specific regulators commonly known as decapping activators or enhancers. These regulatory proteins include the general decapping activators Edc1, 2, and 3, Dhh1, Scd6, Pat1, and the Lsm1-7 complex, as well as the NMD-specific factors, Upf1, 2, and 3. Here, we focus on in vivo mRNA decapping regulation in yeast. We summarize recently uncovered molecular mechanisms that control selective targeting of the yeast decapping enzyme and discuss new roles for specific decapping activators in controlling decapping enzyme targeting, assembly of target-specific decapping complexes, and the monitoring of mRNA translation. Further, we discuss the kinetic contribution of mRNA decapping for overall decay of different substrate mRNAs and highlight experimental evidence pointing to the functional coordination and physical coupling between events in mRNA deadenylation, decapping, and 5'-3' exoribonucleolytic decay.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, 368 Plantation Street, Worcester, MA 01655
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, 368 Plantation Street, Worcester, MA 01655
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5
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Krempl C, Lazzaretti D, Sprangers R. A structural biology view on the enzymes involved in eukaryotic mRNA turnover. Biol Chem 2023; 404:1101-1121. [PMID: 37709756 DOI: 10.1515/hsz-2023-0182] [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: 04/13/2023] [Accepted: 08/24/2023] [Indexed: 09/16/2023]
Abstract
The cellular environment contains numerous ribonucleases that are dedicated to process mRNA transcripts that have been targeted for degradation. Here, we review the three dimensional structures of the ribonuclease complexes (Pan2-Pan3, Ccr4-Not, Xrn1, exosome) and the mRNA decapping enzymes (Dcp2, DcpS) that are involved in mRNA turnover. Structures of major parts of these proteins have been experimentally determined. These enzymes and factors do not act in isolation, but are embedded in interaction networks which regulate enzyme activity and ensure that the appropriate substrates are recruited. The structural details of the higher order complexes that form can, in part, be accurately deduced from known structural data of sub-complexes. Interestingly, many of the ribonuclease and decapping enzymes have been observed in structurally different conformations. Together with experimental data, this highlights that structural changes are often important for enzyme function. We conclude that the known structural data of mRNA decay factors provide important functional insights, but that static structural data needs to be complemented with information regarding protein motions to complete the picture of how transcripts are turned over. In addition, we highlight multiple aspects that influence mRNA turnover rates, but that have not been structurally characterized so far.
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Affiliation(s)
- Christina Krempl
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Daniela Lazzaretti
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
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6
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Bohnsack KE, Yi S, Venus S, Jankowsky E, Bohnsack MT. Cellular functions of eukaryotic RNA helicases and their links to human diseases. Nat Rev Mol Cell Biol 2023; 24:749-769. [PMID: 37474727 DOI: 10.1038/s41580-023-00628-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/22/2023]
Abstract
RNA helicases are highly conserved proteins that use nucleoside triphosphates to bind or remodel RNA, RNA-protein complexes or both. RNA helicases are classified into the DEAD-box, DEAH/RHA, Ski2-like, Upf1-like and RIG-I families, and are the largest class of enzymes active in eukaryotic RNA metabolism - virtually all aspects of gene expression and its regulation involve RNA helicases. Mutation and dysregulation of these enzymes have been linked to a multitude of diseases, including cancer and neurological disorders. In this Review, we discuss the regulation and functional mechanisms of RNA helicases and their roles in eukaryotic RNA metabolism, including in transcription regulation, pre-mRNA splicing, ribosome assembly, translation and RNA decay. We highlight intriguing models that link helicase structure, mechanisms of function (such as local strand unwinding, translocation, winching, RNA clamping and displacing RNA-binding proteins) and biological roles, including emerging connections between RNA helicases and cellular condensates formed through liquid-liquid phase separation. We also discuss associations of RNA helicases with human diseases and recent efforts towards the design of small-molecule inhibitors of these pivotal regulators of eukaryotic gene expression.
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Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
| | - Soon Yi
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah Venus
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Moderna, Cambridge, MA, USA.
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
- Göttingen Centre for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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7
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Hakes AC, Gavis ER. Plasticity of Drosophila germ granules during germ cell development. PLoS Biol 2023; 21:e3002069. [PMID: 37053289 PMCID: PMC10128949 DOI: 10.1371/journal.pbio.3002069] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/25/2023] [Accepted: 03/07/2023] [Indexed: 04/15/2023] Open
Abstract
Compartmentalization of RNAs and proteins into membraneless structures called granules is a ubiquitous mechanism for organizing and regulating cohorts of RNAs. Germ granules are ribonucleoprotein (RNP) assemblies required for germline development across the animal kingdom, but their regulatory roles in germ cells are not fully understood. We show that after germ cell specification, Drosophila germ granules enlarge through fusion and this growth is accompanied by a shift in function. Whereas germ granules initially protect their constituent mRNAs from degradation, they subsequently target a subset of these mRNAs for degradation while maintaining protection of others. This functional shift occurs through the recruitment of decapping and degradation factors to the germ granules, which is promoted by decapping activators and renders these structures P body-like. Disrupting either the mRNA protection or degradation function results in germ cell migration defects. Our findings reveal plasticity in germ granule function that allows them to be repurposed at different stages of development to ensure population of the gonad by germ cells. Additionally, these results reveal an unexpected level of functional complexity whereby constituent RNAs within the same granule type can be differentially regulated.
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Affiliation(s)
- Anna C Hakes
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Elizabeth R Gavis
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
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8
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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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9
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Christie M, Igreja C. eIF4E-homologous protein (4EHP): a multifarious cap-binding protein. FEBS J 2023; 290:266-285. [PMID: 34758096 DOI: 10.1111/febs.16275] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/29/2021] [Accepted: 11/09/2021] [Indexed: 02/05/2023]
Abstract
The cap-binding protein 4EHP/eIF4E2 has been a recent object of interest in the field of post-transcriptional gene regulation and translational control. From ribosome-associated quality control, to RNA decay and microRNA-mediated gene silencing, this member of the eIF4E protein family regulates gene expression through numerous pathways. Low in abundance but ubiquitously expressed, 4EHP interacts with different binding partners to form multiple protein complexes that regulate translation in a variety of biological contexts. Documented functions of 4EHP primarily relate to its role as a translational repressor, but recent findings indicate that it might also participate in the activation of translation in specific settings. In this review, we discuss the known functions, properties and mechanisms that involve 4EHP in the control of gene expression. We also discuss our current understanding of how 4EHP processes are regulated in eukaryotic cells, and the diseases implicated with dysregulation of 4EHP-mediated translational control.
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Affiliation(s)
- Mary Christie
- School of Life and Environmental Sciences, The University of Sydney, NSW, Australia
| | - Cátia Igreja
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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10
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Kim J, Muraoka M, Okada H, Toyoda A, Ajima R, Saga Y. The RNA helicase DDX6 controls early mouse embryogenesis by repressing aberrant inhibition of BMP signaling through miRNA-mediated gene silencing. PLoS Genet 2022; 18:e1009967. [PMID: 36197846 PMCID: PMC9534413 DOI: 10.1371/journal.pgen.1009967] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 08/11/2022] [Indexed: 11/29/2022] Open
Abstract
The evolutionarily conserved RNA helicase DDX6 is a central player in post-transcriptional regulation, but its role during embryogenesis remains elusive. We here show that DDX6 enables proper cell lineage specification from pluripotent cells by analyzing Ddx6 knockout (KO) mouse embryos and employing an in vitro epiblast-like cell (EpiLC) induction system. Our study unveils that DDX6 is an important BMP signaling regulator. Deletion of Ddx6 causes the aberrant upregulation of the negative regulators of BMP signaling, which is accompanied by enhanced expression of Nodal and related genes. Ddx6 KO pluripotent cells acquire higher pluripotency with a strong inclination toward neural lineage commitment. During gastrulation, abnormally expanded Nodal and Eomes expression in the primitive streak likely promotes endoderm cell fate specification while inhibiting mesoderm differentiation. We also genetically dissected major DDX6 pathways by generating Dgcr8, Dcp2, and Eif4enif1 KO models in addition to Ddx6 KO. We found that the miRNA pathway mutant Dgcr8 KO phenocopies Ddx6 KO, indicating that DDX6 mostly works along with the miRNA pathway during early development, whereas its P-body-related functions are dispensable. Therefore, we conclude that DDX6 prevents aberrant upregulation of BMP signaling inhibitors by participating in miRNA-mediated gene silencing processes. Overall, this study delineates how DDX6 affects the development of the three primary germ layers during early mouse embryogenesis and the underlying mechanism of DDX6 function.
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Affiliation(s)
- Jessica Kim
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Masafumi Muraoka
- Mammalian Development Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Japan
| | - Hajime Okada
- Mammalian Development Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Japan
| | - Atsushi Toyoda
- Advanced Genomics Center, National Institute of Genetics, Mishima, Japan
| | - Rieko Ajima
- Mammalian Development Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Japan
- Department of Genetics, The Graduate University for Advanced Studies, SOKENDAI, Mishima, Japan
- * E-mail: (RA); (YS)
| | - Yumiko Saga
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Mammalian Development Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Japan
- Department of Genetics, The Graduate University for Advanced Studies, SOKENDAI, Mishima, Japan
- * E-mail: (RA); (YS)
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11
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He F, Wu C, Jacobson A. Dcp2 C-terminal cis-binding elements control selective targeting of the decapping enzyme by forming distinct decapping complexes. eLife 2022; 11:74410. [PMID: 35604319 PMCID: PMC9170289 DOI: 10.7554/elife.74410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 05/22/2022] [Indexed: 11/13/2022] Open
Abstract
A single Dcp1-Dcp2 decapping enzyme targets diverse classes of yeast mRNAs for decapping-dependent 5' to 3' decay, but the molecular mechanisms controlling mRNA selectivity by the enzyme remain elusive. Through extensive genetic analyses we reveal that Dcp2 C-terminal domain cis-regulatory elements control decapping enzyme target specificity by orchestrating formation of distinct decapping complexes. Two Upf1-binding motifs direct the decapping enzyme to NMD substrates, a single Edc3-binding motif targets both Edc3 and Dhh1 substrates, and Pat1-binding leucine-rich motifs target Edc3 and Dhh1 substrates under selective conditions. Although it functions as a unique targeting component of specific complexes, Edc3 is a common component of multiple complexes. Scd6 and Xrn1 also have specific binding sites on Dcp2, allowing them to be directly recruited to decapping complexes. Collectively, our results demonstrate that Upf1, Edc3, Scd6, and Pat1 function as regulatory subunits of the holo-decapping enzyme, controlling both its substrate specificity and enzymatic activation.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Chan Wu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, United States
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12
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Vidya E, Duchaine TF. Eukaryotic mRNA Decapping Activation. Front Genet 2022; 13:832547. [PMID: 35401681 PMCID: PMC8984151 DOI: 10.3389/fgene.2022.832547] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
The 5′-terminal cap is a fundamental determinant of eukaryotic gene expression which facilitates cap-dependent translation and protects mRNAs from exonucleolytic degradation. Enzyme-directed hydrolysis of the cap (decapping) decisively affects mRNA expression and turnover, and is a heavily regulated event. Following the identification of the decapping holoenzyme (Dcp1/2) over two decades ago, numerous studies revealed the complexity of decapping regulation across species and cell types. A conserved set of Dcp1/2-associated proteins, implicated in decapping activation and molecular scaffolding, were identified through genetic and molecular interaction studies, and yet their exact mechanisms of action are only emerging. In this review, we discuss the prevailing models on the roles and assembly of decapping co-factors, with considerations of conservation across species and comparison across physiological contexts. We next discuss the functional convergences of decapping machineries with other RNA-protein complexes in cytoplasmic P bodies and compare current views on their impact on mRNA stability and translation. Lastly, we review the current models of decapping activation and highlight important gaps in our current understanding.
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Affiliation(s)
- Elva Vidya
- Goodman Cancer Institute, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Thomas F. Duchaine
- Goodman Cancer Institute, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
- *Correspondence: Thomas F. Duchaine,
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13
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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: 44] [Impact Index Per Article: 22.0] [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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14
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Zhang Y, Wang K, Yang K, Shi Y, Hong J. Insight into the interaction between the RNA helicase CGH-1 and EDC-3 and its implications. Sci Rep 2021; 11:20359. [PMID: 34645931 PMCID: PMC8514580 DOI: 10.1038/s41598-021-99919-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 09/30/2021] [Indexed: 12/03/2022] Open
Abstract
Previous studies indicated that the P-body components, CGH-1 and EDC-3 may play a crucial role in the regulation of lifespan in Caenorhabditis elegans. Homo sapiens DDX6 or Saccharomyces cerevisiae Dhh1p (CGH-1 in C. elegans) could form complexes with EDC3 (Edc3p in yeast), respectively, which is significant for translation inhibition and mRNA decay. However, it is currently unclear how CGH-1 can be recognized by EDC-3 in C. elegans. Here, we provided structural and biochemical insights into the interaction between CGH-1 and EDC-3. Combined with homology modeling, mutation, and ITC assays, we uncovered an interface between CGH-1 RecA2 domain and EDC-3 FDF-FEK. Additionally, GST-pulldown and co-localization experiments confirmed the interaction between CGH-1 and EDC-3 in vitro and in vivo. We also analyzed PATR-1-binding interface on CGH-1 RecA2 by ITC assays. Moreover, we unveiled the similarity and differences of the binding mode between EDC-3 and CAR-1 or PATR-1. Taken together, these findings provide insights into the recognition of DEAD-box protein CGH-1 by EDC-3 FDF-FEK motif, suggesting important functional implications.
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Affiliation(s)
- Yong Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
- Ministry of Education Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science and Technology of China, Hefei, People's Republic of China
| | - Ke Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
- Ministry of Education Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science and Technology of China, Hefei, People's Republic of China
| | - Kanglong Yang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
- Ministry of Education Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science and Technology of China, Hefei, People's Republic of China
| | - Yunyu Shi
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
- Ministry of Education Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science and Technology of China, Hefei, People's Republic of China
| | - Jingjun Hong
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China.
- Ministry of Education Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science and Technology of China, Hefei, People's Republic of China.
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15
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Tishinov K, Spang A. The mRNA decapping complex is buffered by nuclear localization. J Cell Sci 2021; 134:272313. [PMID: 34435633 DOI: 10.1242/jcs.259156] [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: 07/15/2021] [Accepted: 08/17/2021] [Indexed: 01/08/2023] Open
Abstract
mRNA decay is a key step in regulating the cellular proteome. Processing bodies (P-bodies) are thought to be sites of mRNA decay and/or storage. P-body units assemble into P-body granules under stress conditions. How this assembly is regulated, however, remains poorly understood. Here, we show, in the yeast Saccharomyces cerevisiae, that the translational repressor Scd6 and the decapping stimulator Edc3 act partially redundantly in P-body assembly by sequestering the Dcp1-Dcp2 (denoted Dcp1/2) decapping complex in the cytoplasm and preventing it from becoming imported into the nucleus by the karyopherin β protein Kap95. One of two nuclear localization signals in Dcp2 overlaps with the RNA-binding site, suggesting an additional mechanism to regulate Dcp1/2 localization. Nuclear Dcp1/2 does not drive mRNA decay and might be stored there as a readily releasable pool, indicating a dynamic equilibrium between cytoplasmic and nuclear Dcp1/2. Cytoplasmic Dcp1/2 is linked to Dhh1 via Edc3. Functional P-bodies are present at the endoplasmic reticulum where Dcp2 potentially acts to increase the local concentration of Dhh1 through interaction with Edc3 to drive phase separation and hence P-body formation.
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Affiliation(s)
- Kiril Tishinov
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
| | - Anne Spang
- Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland
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16
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Mutations in genes encoding regulators of mRNA decapping and translation initiation: links to intellectual disability. Biochem Soc Trans 2021; 48:1199-1211. [PMID: 32412080 PMCID: PMC7329352 DOI: 10.1042/bst20200109] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 12/12/2022]
Abstract
Intellectual disability (ID) affects at least 1% of the population, and typically presents in the first few years of life. ID is characterized by impairments in cognition and adaptive behavior and is often accompanied by further delays in language and motor skills, as seen in many neurodevelopmental disorders (NDD). Recent widespread high-throughput approaches that utilize whole-exome sequencing or whole-genome sequencing have allowed for a considerable increase in the identification of these pathogenic variants in monogenic forms of ID. Notwithstanding this progress, the molecular and cellular consequences of the identified mutations remain mostly unknown. This is particularly important as the associated protein dysfunctions are the prerequisite to the identification of targets for novel drugs of these rare disorders. Recent Next-Generation sequencing-based studies have further established that mutations in genes encoding proteins involved in RNA metabolism are a major cause of NDD. Here, we review recent studies linking germline mutations in genes encoding factors mediating mRNA decay and regulators of translation, namely DCPS, EDC3, DDX6 helicase and ID. These RNA-binding proteins have well-established roles in mRNA decapping and/or translational repression, and the mutations abrogate their ability to remove 5′ caps from mRNA, diminish their interactions with cofactors and stabilize sub-sets of transcripts. Additional genes encoding RNA helicases with roles in translation including DDX3X and DHX30 have also been linked to NDD. Given the speed in the acquisition, analysis and sharing of sequencing data, and the importance of post-transcriptional regulation for brain development, we anticipate mutations in more such factors being identified and functionally characterized.
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17
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Pühringer T, Hohmann U, Fin L, Pacheco-Fiallos B, Schellhaas U, Brennecke J, Plaschka C. Structure of the human core transcription-export complex reveals a hub for multivalent interactions. eLife 2020; 9:e61503. [PMID: 33191911 PMCID: PMC7744094 DOI: 10.7554/elife.61503] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 11/13/2020] [Indexed: 12/24/2022] Open
Abstract
The export of mRNA from nucleus to cytoplasm requires the conserved and essential transcription and export (TREX) complex (THO-UAP56/DDX39B-ALYREF). TREX selectively binds mRNA maturation marks and licenses mRNA for nuclear export by loading the export factor NXF1-NXT1. How TREX integrates these marks and achieves high selectivity for mature mRNA is poorly understood. Here, we report the cryo-electron microscopy structure of the human THO-UAP56/DDX39B complex at 3.3 Å resolution. The seven-subunit THO-UAP56/DDX39B complex multimerizes into a 28-subunit tetrameric assembly, suggesting that selective recognition of mature mRNA is facilitated by the simultaneous sensing of multiple, spatially distant mRNA regions and maturation marks. Two UAP56/DDX39B RNA helicases are juxtaposed at each end of the tetramer, which would allow one bivalent ALYREF protein to bridge adjacent helicases and regulate the TREX-mRNA interaction. Our structural and biochemical results suggest a conserved model for TREX complex function that depends on multivalent interactions between proteins and mRNA.
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Affiliation(s)
- Thomas Pühringer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Ulrich Hohmann
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)ViennaAustria
| | - Laura Fin
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Belén Pacheco-Fiallos
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Ulla Schellhaas
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Julius Brennecke
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA)ViennaAustria
| | - Clemens Plaschka
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
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18
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Zuo Z, Roux ME, Saemundsson HP, Müller M, Munne Bosch S, Petersen M. The Arabidopsis thaliana mRNA decay factor PAT1 functions in osmotic stress responses and decaps ABA-responsive genes. FEBS Lett 2020; 595:253-263. [PMID: 33124072 DOI: 10.1002/1873-3468.13977] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 11/12/2022]
Abstract
mRNA decapping plays essential roles in regulating gene expression during cellular reprogramming in response to developmental and environmental cues. The evolutionarily conserved PAT1 proteins activate decapping by binding mRNA, recruiting other decapping components, and promoting processing body (PB) assembly. Arabidopsis encodes 3 PAT proteins: PAT1, PATH1, and PATH2. Here, we report that only pat1 mutants exhibit hypersensitivity to ABA and that transcripts of ABA-responsive genes, but not those of ABA biosynthesis genes, persist longer in these mutants. The pat1 mutants also exhibit increased resistance to drought stress and resistance to Pythium irregulare. This is supported by assays showing that PAT1 functions specifically in decapping of the canonical ABA-responsive gene COR15A. In summary, PAT1 protein mediates decay of ABA-responsive genes and, thus, regulates stress responses.
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Affiliation(s)
- Zhangli Zuo
- Department of Biology, Faculty of Science, University of Copenhagen, Denmark
| | - Milena Edna Roux
- Department of Biology, Faculty of Science, University of Copenhagen, Denmark.,Novo Nordisk, Regulatory Affairs Durable Devices and Needles, Søborg, Denmark
| | | | - Maren Müller
- Department of Evolutionary Biology, Ecology & Environmental Sciences, Faculty of Biology, University of Barcelona, Spain
| | - Sergi Munne Bosch
- Department of Evolutionary Biology, Ecology & Environmental Sciences, Faculty of Biology, University of Barcelona, Spain
| | - Morten Petersen
- Department of Biology, Faculty of Science, University of Copenhagen, Denmark
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19
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Lobel JH, Gross JD. Pdc2/Pat1 increases the range of decay factors and RNA bound by the Lsm1-7 complex. RNA (NEW YORK, N.Y.) 2020; 26:1380-1388. [PMID: 32513655 PMCID: PMC7491320 DOI: 10.1261/rna.075812.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/29/2020] [Indexed: 05/31/2023]
Abstract
Pat1, known as Pdc2 in fission yeast, promotes the activation and assembly of multiple proteins during mRNA decay. After deadenylation, the Pat1/Lsm1-7 complex binds to transcripts containing oligo(A) tails, which can be modified by the addition of several terminal uridine residues. Pat1 enhances Lsm1-7 binding to the 3' end, but it is unknown how this interaction is influenced by nucleotide composition. Here we examine Pat1/Lsm1-7 binding to a series of oligoribonucleotides containing different A/U contents using recombinant purified proteins from fission yeast. We observe a positive correlation between fractional uridine content and Lsm1-7 binding affinity. Addition of Pat1 broadens RNA specificity of Lsm1-7 by enhancing binding to A-rich RNAs and increases cooperativity on all oligonucleotides tested. Consistent with increased cooperativity, Pat1 promotes multimerization of the Lsm1-7 complex, which is potentiated by RNA binding. Furthermore, the inherent ability of Pat1 to multimerize drives liquid-liquid phase separation with multivalent decapping enzyme complexes of Dcp1/Dcp2. Our results uncover how Pat1 regulates RNA binding and higher order assembly by mRNA decay factors.
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Affiliation(s)
- Joseph H Lobel
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, California 94158, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, USA
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, USA
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20
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Chantarachot T, Sorenson RS, Hummel M, Ke H, Kettenburg AT, Chen D, Aiyetiwa K, Dehesh K, Eulgem T, Sieburth LE, Bailey-Serres J. DHH1/DDX6-like RNA helicases maintain ephemeral half-lives of stress-response mRNAs. NATURE PLANTS 2020; 6:675-685. [PMID: 32483330 DOI: 10.1038/s41477-020-0681-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 04/29/2020] [Indexed: 05/21/2023]
Abstract
Gene transcription is counterbalanced by messenger RNA decay processes that regulate transcript quality and quantity. We show here that the evolutionarily conserved DHH1/DDX6-like RNA hellicases of Arabidopsis thaliana control the ephemerality of a subset of cellular mRNAs. These RNA helicases co-localize with key markers of processing bodies and stress granules and contribute to their subcellular dynamics. They function to limit the precocious accumulation and ribosome association of stress-responsive mRNAs involved in auto-immunity and growth inhibition under non-stress conditions. Given the conservation of this RNA helicase subfamily, they may control basal levels of conditionally regulated mRNAs in diverse eukaryotes, accelerating responses without penalty.
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Affiliation(s)
- Thanin Chantarachot
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Reed S Sorenson
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Maureen Hummel
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Haiyan Ke
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Alek T Kettenburg
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Daniel Chen
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Karen Aiyetiwa
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Katayoon Dehesh
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Thomas Eulgem
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Leslie E Sieburth
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Julia Bailey-Serres
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA.
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21
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Lobel JH, Tibble RW, Gross JD. Pat1 activates late steps in mRNA decay by multiple mechanisms. Proc Natl Acad Sci U S A 2019; 116:23512-23517. [PMID: 31690658 PMCID: PMC6876151 DOI: 10.1073/pnas.1905455116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Pat1 is a hub for mRNA metabolism, acting in pre-mRNA splicing, translation repression, and mRNA decay. A critical step in all 5'-3' mRNA decay pathways is removal of the 5' cap structure, which precedes and permits digestion of the RNA body by conserved exonucleases. During bulk 5'-3' decay, the Pat1/Lsm1-7 complex engages mRNA at the 3' end and promotes hydrolysis of the cap structure by Dcp1/Dcp2 at the 5' end through an unknown mechanism. We reconstitute Pat1 with 5' and 3' decay factors and show how it activates multiple steps in late mRNA decay. First, we find that Pat1 stabilizes binding of the Lsm1-7 complex to RNA using two conserved short-linear interaction motifs. Second, Pat1 directly activates decapping by binding elements in the disordered C-terminal extension of Dcp2, alleviating autoinhibition and promoting substrate binding. Our results uncover the molecular mechanism of how separate domains of Pat1 coordinate the assembly and activation of a decapping messenger ribonucleoprotein (mRNP) that promotes 5'-3' mRNA degradation.
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Affiliation(s)
- Joseph H Lobel
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, CA 94158
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158
| | - Ryan W Tibble
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, CA 94158
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158
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22
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Damman R, Schütz S, Luo Y, Weingarth M, Sprangers R, Baldus M. Atomic-level insight into mRNA processing bodies by combining solid and solution-state NMR spectroscopy. Nat Commun 2019; 10:4536. [PMID: 31586050 PMCID: PMC6778109 DOI: 10.1038/s41467-019-12402-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/09/2019] [Indexed: 01/07/2023] Open
Abstract
Liquid-liquid phase separation is increasingly recognized as a process involved in cellular organization. Thus far, a detailed structural characterization of this intrinsically heterogeneous process has been challenging. Here we combine solid- and solution-state NMR spectroscopy to obtain atomic-level insights into the assembly and maturation of cytoplasmic processing bodies that contain mRNA as well as enzymes involved in mRNA degradation. In detail, we have studied the enhancer of decapping 3 (Edc3) protein that is a central hub for processing body formation in yeast. Our results reveal that Edc3 domains exhibit diverse levels of structural organization and dynamics after liquid-liquid phase separation. In addition, we find that interactions between the different Edc3 domains and between Edc3 and RNA in solution are largely preserved in the condensed protein state, allowing processing bodies to rapidly form and dissociate upon small alterations in the cellular environment.
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Affiliation(s)
- Reinier Damman
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Stefan Schütz
- Department of Biophysics I, University of Regensburg, 93053, Regensburg, Germany
| | - Yanzhang Luo
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Markus Weingarth
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Remco Sprangers
- Department of Biophysics I, University of Regensburg, 93053, Regensburg, Germany.
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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23
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Balak C, Benard M, Schaefer E, Iqbal S, Ramsey K, Ernoult-Lange M, Mattioli F, Llaci L, Geoffroy V, Courel M, Naymik M, Bachman KK, Pfundt R, Rump P, Ter Beest J, Wentzensen IM, Monaghan KG, McWalter K, Richholt R, Le Béchec A, Jepsen W, De Both M, Belnap N, Boland A, Piras IS, Deleuze JF, Szelinger S, Dollfus H, Chelly J, Muller J, Campbell A, Lal D, Rangasamy S, Mandel JL, Narayanan V, Huentelman M, Weil D, Piton A. Rare De Novo Missense Variants in RNA Helicase DDX6 Cause Intellectual Disability and Dysmorphic Features and Lead to P-Body Defects and RNA Dysregulation. Am J Hum Genet 2019; 105:509-525. [PMID: 31422817 PMCID: PMC6731366 DOI: 10.1016/j.ajhg.2019.07.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 07/17/2019] [Indexed: 01/13/2023] Open
Abstract
The human RNA helicase DDX6 is an essential component of membrane-less organelles called processing bodies (PBs). PBs are involved in mRNA metabolic processes including translational repression via coordinated storage of mRNAs. Previous studies in human cell lines have implicated altered DDX6 in molecular and cellular dysfunction, but clinical consequences and pathogenesis in humans have yet to be described. Here, we report the identification of five rare de novo missense variants in DDX6 in probands presenting with intellectual disability, developmental delay, and similar dysmorphic features including telecanthus, epicanthus, arched eyebrows, and low-set ears. All five missense variants (p.His372Arg, p.Arg373Gln, p.Cys390Arg, p.Thr391Ile, and p.Thr391Pro) are located in two conserved motifs of the RecA-2 domain of DDX6 involved in RNA binding, helicase activity, and protein-partner binding. We use functional studies to demonstrate that the first variants identified (p.Arg373Gln and p.Cys390Arg) cause significant defects in PB assembly in primary fibroblast and model human cell lines. These variants' interactions with several protein partners were also disrupted in immunoprecipitation assays. Further investigation via complementation assays included the additional variants p.Thr391Ile and p.Thr391Pro, both of which, similarly to p.Arg373Gln and p.Cys390Arg, demonstrated significant defects in P-body assembly. Complementing these molecular findings, modeling of the variants on solved protein structures showed distinct spatial clustering near known protein binding regions. Collectively, our clinical and molecular data describe a neurodevelopmental syndrome associated with pathogenic missense variants in DDX6. Additionally, we suggest DDX6 join the DExD/H-box genes DDX3X and DHX30 in an emerging class of neurodevelopmental disorders involving RNA helicases.
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Affiliation(s)
- Chris Balak
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA.
| | - Marianne Benard
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire de Biologie du Développement, F-75005 Paris, France
| | - Elise Schaefer
- Medical Genetics Department, University Hospitals of Strasbourg, the Institute of Medical Genetics of Alsace, 67000 Strasbourg, France; Laboratoire de Génétique Médicale, Institut de Génétique Médicale d'Alsace, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, 67081 Strasbourg, France
| | - Sumaiya Iqbal
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Keri Ramsey
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Michèle Ernoult-Lange
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire de Biologie du Développement, F-75005 Paris, France
| | - Francesca Mattioli
- Institute of Genetics and Molecular and Cellular Biology, Illkirch, France; French National Center for Scientific Research, UMR7104, 67400 Illkirch, France; National Institute of Health and Medical Research U964, 67400 Illkirch, France; University of Strasbourg, 67081 Illkirch, France
| | - Lorida Llaci
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Véronique Geoffroy
- Laboratoire de Génétique Médicale, Institut de Génétique Médicale d'Alsace, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, 67081 Strasbourg, France
| | - Maité Courel
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire de Biologie du Développement, F-75005 Paris, France
| | - Marcus Naymik
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | | | - Rolph Pfundt
- Department of Genetics, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, the Netherlands
| | - Patrick Rump
- Radboud University Nijmegen Medical Center, Department of Human Genetics, Division of Genome Diagnostics, 6525 GA Nijmegen, the Netherlands
| | - Johanna Ter Beest
- Department of Genetics, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, the Netherlands
| | | | | | | | - Ryan Richholt
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA
| | - Antony Le Béchec
- Medical Bioinformatics Unit, UF7363, Strasbourg University Hospital, 67000 Strasbourg, France
| | - Wayne Jepsen
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Matt De Both
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Newell Belnap
- Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Anne Boland
- Centre National de Recherche en Génomique Humaine, Institut de Biologie François Jacob, CEA, Université Paris-Saclay, F-91057, Evry, France
| | - Ignazio S Piras
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Jean-François Deleuze
- Centre National de Recherche en Génomique Humaine, Institut de Biologie François Jacob, CEA, Université Paris-Saclay, F-91057, Evry, France
| | - Szabolcs Szelinger
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Hélène Dollfus
- Medical Genetics Department, University Hospitals of Strasbourg, the Institute of Medical Genetics of Alsace, 67000 Strasbourg, France; Laboratoire de Génétique Médicale, Institut de Génétique Médicale d'Alsace, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, 67081 Strasbourg, France
| | - Jamel Chelly
- Institute of Genetics and Molecular and Cellular Biology, Illkirch, France; French National Center for Scientific Research, UMR7104, 67400 Illkirch, France; National Institute of Health and Medical Research U964, 67400 Illkirch, France; University of Strasbourg, 67081 Illkirch, France; Molecular Genetics Unit, Strasbourg University Hospital, 67000 Strasbourg, France
| | - Jean Muller
- Laboratoire de Génétique Médicale, Institut de Génétique Médicale d'Alsace, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, 67081 Strasbourg, France; Molecular Genetics Unit, Strasbourg University Hospital, 67000 Strasbourg, France
| | - Arthur Campbell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Dennis Lal
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA; Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH 44195, USA; Cologne Center for Genomics, University of Cologne, 50931 Cologne, Germany
| | - Sampathkumar Rangasamy
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Jean-Louis Mandel
- Institute of Genetics and Molecular and Cellular Biology, Illkirch, France; French National Center for Scientific Research, UMR7104, 67400 Illkirch, France; National Institute of Health and Medical Research U964, 67400 Illkirch, France; University of Strasbourg, 67081 Illkirch, France; University of Strasbourg Institute of Advanced Studies, 67081 Strasbourg, France
| | - Vinodh Narayanan
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Matt Huentelman
- Translational Genomics Research Institute, Neurogenomics Division, Phoenix, AZ 85004, USA; Translational Genomics Research Institute's Center for Rare Childhood Disorders, Phoenix, AZ 85012, USA
| | - Dominique Weil
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire de Biologie du Développement, F-75005 Paris, France
| | - Amélie Piton
- Institute of Genetics and Molecular and Cellular Biology, Illkirch, France; French National Center for Scientific Research, UMR7104, 67400 Illkirch, France; National Institute of Health and Medical Research U964, 67400 Illkirch, France; University of Strasbourg, 67081 Illkirch, France; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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24
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Wurm JP, Sprangers R. Dcp2: an mRNA decapping enzyme that adopts many different shapes and forms. Curr Opin Struct Biol 2019; 59:115-123. [PMID: 31473440 PMCID: PMC6900585 DOI: 10.1016/j.sbi.2019.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/22/2019] [Accepted: 07/30/2019] [Indexed: 02/01/2023]
Abstract
Structure of the active state of the Dcp2 decapping enzyme. Insights into the structural states that are sampled in solution. Details regarding the intermolecular network that Dcp2 is embedded in.
Eukaryotic mRNAs contain a 5’ cap structure that protects the transcript against rapid exonucleolytic degradation. The regulation of cellular mRNA levels therefore depends on a precise control of the mRNA decapping pathways. The major mRNA decapping enzyme in eukaryotic cells is Dcp2. It is regulated by interactions with several activators, including Dcp1, Edc1, and Edc3, as well as by an autoinhibition mechanism. The structural and mechanistical characterization of Dcp2 complexes has long been impeded by the high flexibility and dynamic nature of the enzyme. Here we review recent insights into the catalytically active conformation of the mRNA decapping complex, the mode of action of decapping activators and the large interactions network that Dcp2 is embedded in.
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Affiliation(s)
- Jan Philip Wurm
- Department of Biophysics I, University of Regensburg, 93053, Regensburg, Germany.
| | - Remco Sprangers
- Department of Biophysics I, University of Regensburg, 93053, Regensburg, Germany.
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25
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Peter D, Ruscica V, Bawankar P, Weber R, Helms S, Valkov E, Igreja C, Izaurralde E. Molecular basis for GIGYF-Me31B complex assembly in 4EHP-mediated translational repression. Genes Dev 2019; 33:1355-1360. [PMID: 31439631 PMCID: PMC6771390 DOI: 10.1101/gad.329219.119] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 07/18/2019] [Indexed: 11/24/2022]
Abstract
In this study, Peter et al. provide new insights into how GIGYF proteins function together with DDX6 in the regulation of mRNA expression. They used structural analysis, in vivo expression analysis, and biochemical assays to show that GIGYF contains a motif that is necessary and sufficient for direct interaction with Me31B/DDX6, and their findings advance our understanding of the mechanism and assembly of the 4EHP–GIGYF–DDX6 repressor complex. GIGYF (Grb10-interacting GYF [glycine–tyrosine–phenylalanine domain]) proteins coordinate with 4EHP (eIF4E [eukaryotic initiation factor 4E] homologous protein), the DEAD (Asp–Glu–Ala–Asp)-box helicase Me31B/DDX6, and mRNA-binding proteins to elicit transcript-specific repression. However, the underlying molecular mechanism remains unclear. Here, we report that GIGYF contains a motif necessary and sufficient for direct interaction with Me31B/DDX6. A 2.4 Å crystal structure of the GIGYF–Me31B complex reveals that this motif arranges into a coil connected to a β hairpin on binding to conserved hydrophobic patches on the Me31B RecA2 domain. Structure-guided mutants indicate that 4EHP–GIGYF–DDX6 complex assembly is required for tristetraprolin-mediated down-regulation of an AU-rich mRNA, thus revealing the molecular principles of translational repression.
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Affiliation(s)
- Daniel Peter
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.,European Molecular Biology Laboratory, 38042 Grenoble Cedex 9, France
| | - Vincenzo Ruscica
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Praveen Bawankar
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.,Institute of Molecular Biology, 55128 Mainz, Germany
| | - Ramona Weber
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Sigrun Helms
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Eugene Valkov
- 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
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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26
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Vindry C, Weil D, Standart N. Pat1 RNA-binding proteins: Multitasking shuttling proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1557. [PMID: 31231973 DOI: 10.1002/wrna.1557] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/02/2019] [Accepted: 05/07/2019] [Indexed: 12/11/2022]
Abstract
Post-transcriptional regulation of gene expression is largely achieved at the level of splicing in the nucleus, and translation and mRNA decay in the cytosol. While the regulation may be global, through the direct inhibition of central factors, such as the spliceosome, translation initiation factors and mRNA decay enzymes, in many instances transcripts bearing specific sequences or particular features are regulated by RNA-binding factors which mobilize or impede recruitment of these machineries. This review focuses on the Pat1 family of RNA-binding proteins, conserved from yeast to man, that enhance the removal of the 5' cap by the decapping enzyme Dcp1/2, leading to mRNA decay and also have roles in translational repression. Like Dcp1/2, other decapping coactivators, including DDX6 and Edc3, and translational repressor proteins, Pat1 proteins are enriched in cytoplasmic P-bodies, which have a principal role in mRNA storage. They also concentrate in nuclear Cajal-bodies and splicing speckles and in man, impact splice site choice in some pre-mRNAs. Pivotal to these functions is the association of Pat1 proteins with distinct heptameric Lsm complexes: the cytosolic Pat1/Lsm1-7 complex mediates mRNA decay and the nuclear Pat1/Lsm2-8 complex alternative splicing. This dual role of human Pat1b illustrates the power of paralogous complexes to impact distinct processes in separate compartments. The review highlights our recent findings that Pat1b mediates the decay of AU-rich mRNAs, which are particularly enriched in P-bodies, unlike the decapping activator DDX6, which acts on GC-rich mRNAs, that tend to be excluded from P-bodies, and discuss the implications for mRNA decay pathways. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNRNA Processing > Splicing Regulation/Alternative Splicing Translation > Translation Regulation.
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Affiliation(s)
- Caroline Vindry
- Centre International de Recherche en Infectiologie, CIRI, Lyon, France
| | - Dominique Weil
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire de Biologie du Développement, Paris, France
| | - Nancy Standart
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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27
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Duchaine TF, Fabian MR. Mechanistic Insights into MicroRNA-Mediated Gene Silencing. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032771. [PMID: 29959194 DOI: 10.1101/cshperspect.a032771] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) posttranscriptionally regulate gene expression by repressing protein synthesis and exert a broad influence over development, physiology, adaptation, and disease. Over the past two decades, great strides have been made toward elucidating how miRNAs go about shutting down messenger RNA (mRNA) translation and promoting mRNA decay.
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Affiliation(s)
- Thomas F Duchaine
- Department of Biochemistry & Goodman Cancer Research Centre, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Marc R Fabian
- Department of Oncology, McGill University, Montreal, Quebec H3G 1Y6, Canada.,Lady Davis Institute, Jewish General Hospital, Montreal, Quebec H3T 1E2, Canada
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28
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Mayya VK, Duchaine TF. Ciphers and Executioners: How 3'-Untranslated Regions Determine the Fate of Messenger RNAs. Front Genet 2019; 10:6. [PMID: 30740123 PMCID: PMC6357968 DOI: 10.3389/fgene.2019.00006] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/07/2019] [Indexed: 12/29/2022] Open
Abstract
The sequences and structures of 3'-untranslated regions (3'UTRs) of messenger RNAs govern their stability, localization, and expression. 3'UTR regulatory elements are recognized by a wide variety of trans-acting factors that include microRNAs (miRNAs), their associated machinery, and RNA-binding proteins (RBPs). In turn, these factors instigate common mechanistic strategies to execute the regulatory programs encoded by 3'UTRs. Here, we review classes of factors that recognize 3'UTR regulatory elements and the effector machineries they guide toward mRNAs to dictate their expression and fate. We outline illustrative examples of competitive, cooperative, and coordinated interplay such as mRNA localization and localized translation. We further review the recent advances in the study of mRNP granules and phase transition, and their possible significance for the functions of 3'UTRs. Finally, we highlight some of the most recent strategies aimed at deciphering the complexity of the regulatory codes of 3'UTRs, and identify some of the important remaining challenges.
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Affiliation(s)
| | - Thomas F. Duchaine
- Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, QC, Canada
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29
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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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30
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He F, Celik A, Wu C, Jacobson A. General decapping activators target different subsets of inefficiently translated mRNAs. eLife 2018; 7:34409. [PMID: 30520724 PMCID: PMC6300357 DOI: 10.7554/elife.34409] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 12/04/2018] [Indexed: 12/18/2022] Open
Abstract
The Dcp1-Dcp2 decapping enzyme and the decapping activators Pat1, Dhh1, and Lsm1 regulate mRNA decapping, but their mechanistic integration is unknown. We analyzed the gene expression consequences of deleting PAT1, LSM1, or DHH1, or the DCP2 C-terminal domain, and found that: i) the Dcp2 C-terminal domain is an effector of both negative and positive regulation; ii) rather than being global activators of decapping, Pat1, Lsm1, and Dhh1 directly target specific subsets of yeast mRNAs and loss of the functions of each of these factors has substantial indirect consequences for genome-wide mRNA expression; and iii) transcripts targeted by Pat1, Lsm1, and Dhh1 exhibit only partial overlap, are generally translated inefficiently, and, as expected, are targeted to decapping-dependent decay. Our results define the roles of Pat1, Lsm1, and Dhh1 in decapping of general mRNAs and suggest that these factors may monitor mRNA translation and target unique features of individual mRNAs.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
| | - Alper Celik
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
| | - Chan Wu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
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31
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Mugridge JS, Coller J, Gross JD. Structural and molecular mechanisms for the control of eukaryotic 5'-3' mRNA decay. Nat Struct Mol Biol 2018; 25:1077-1085. [PMID: 30518847 DOI: 10.1038/s41594-018-0164-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/31/2018] [Indexed: 12/15/2022]
Abstract
5'-3' RNA decay pathways are critical for quality control and regulation of gene expression. Structural and biochemical studies have provided insights into the key nucleases that carry out deadenylation, decapping, and exonucleolysis during 5'-3' decay, but detailed understanding of how these activities are coordinated is only beginning to emerge. Here we review recent mechanistic insights into the control of 5'-3' RNA decay, including coupling between translation and decay, coordination between the complexes and activities that process 5' and 3' RNA termini, conformational control of enzymatic activity, liquid phase separation, and RNA modifications.
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Affiliation(s)
- Jeffrey S Mugridge
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Jeff Coller
- The Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH, USA
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA.
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32
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Charenton C, Graille M. mRNA decapping: finding the right structures. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2018.0164. [PMID: 30397101 DOI: 10.1098/rstb.2018.0164] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2018] [Indexed: 12/14/2022] Open
Abstract
In eukaryotes, the elimination of the m7GpppN mRNA cap, a process known as decapping, is a critical, largely irreversible and highly regulated step of mRNA decay that withdraws the targeted mRNAs from the pool of translatable templates. The decapping reaction is catalysed by a multi-protein complex formed by the Dcp2 catalytic subunit and its Dcp1 cofactor, a holoenzyme that is poorly active on its own and needs several accessory proteins (Lsm1-7 complex, Pat1, Edc1-2, Edc3 and/or EDC4) to be fully efficient. Here, we discuss the several crystal structures of Dcp2 domains bound to various partners (proteins or small molecules) determined in the last couple of years that have considerably improved our current understanding of how Dcp2, assisted by its various activators, is recruited to its mRNA targets and adopts its active conformation upon substrate recognition. We also describe how, over the years, elegant integrative structural biology approaches combined to biochemistry and genetics led to the identification of the correct structure of the active Dcp1-Dcp2 holoenzyme among the many available conformations trapped by X-ray crystallography.This article is part of the theme issue '5' and 3' modifications controlling RNA degradation'.
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Affiliation(s)
- Clément Charenton
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, F-91128 Palaiseau cedex, France
| | - Marc Graille
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, F-91128 Palaiseau cedex, France
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33
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Heck AM, Wilusz J. The Interplay between the RNA Decay and Translation Machinery in Eukaryotes. Cold Spring Harb Perspect Biol 2018; 10:a032839. [PMID: 29311343 PMCID: PMC5932591 DOI: 10.1101/cshperspect.a032839] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
RNA decay plays a major role in regulating gene expression and is tightly networked with other aspects of gene expression to effectively coordinate post-transcriptional regulation. The goal of this work is to provide an overview of the major factors and pathways of general messenger RNA (mRNA) decay in eukaryotic cells, and then discuss the effective interplay of this cytoplasmic process with the protein synthesis machinery. Given the transcript-specific and fluid nature of mRNA stability in response to changing cellular conditions, understanding the fundamental networking between RNA decay and translation will provide a foundation for a complete mechanistic understanding of this important aspect of cell biology.
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Affiliation(s)
- Adam M Heck
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80525
- Program in Cell & Molecular Biology, Colorado State University, Fort Collins, Colorado 80525
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80525
- Program in Cell & Molecular Biology, Colorado State University, Fort Collins, Colorado 80525
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34
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Brandmann T, Fakim H, Padamsi Z, Youn JY, Gingras AC, Fabian MR, Jinek M. Molecular architecture of LSM14 interactions involved in the assembly of mRNA silencing complexes. EMBO J 2018; 37:embj.201797869. [PMID: 29510985 DOI: 10.15252/embj.201797869] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 01/19/2018] [Accepted: 01/21/2018] [Indexed: 11/09/2022] Open
Abstract
The LSM domain-containing protein LSM14/Rap55 plays a role in mRNA decapping, translational repression, and RNA granule (P-body) assembly. How LSM14 interacts with the mRNA silencing machinery, including the eIF4E-binding protein 4E-T and the DEAD-box helicase DDX6, is poorly understood. Here we report the crystal structure of the LSM domain of LSM14 bound to a highly conserved C-terminal fragment of 4E-T. The 4E-T C-terminus forms a bi-partite motif that wraps around the N-terminal LSM domain of LSM14. We also determined the crystal structure of LSM14 bound to the C-terminal RecA-like domain of DDX6. LSM14 binds DDX6 via a unique non-contiguous motif with distinct directionality as compared to other DDX6-interacting proteins. Together with mutational and proteomic studies, the LSM14-DDX6 structure reveals that LSM14 has adopted a divergent mode of binding DDX6 in order to support the formation of mRNA silencing complexes and P-body assembly.
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Affiliation(s)
- Tobias Brandmann
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Hana Fakim
- Department of Oncology, McGill University, Montreal, QC, Canada.,Segal Cancer Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Zoya Padamsi
- Department of Oncology, McGill University, Montreal, QC, Canada.,Segal Cancer Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Ji-Young Youn
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Marc R Fabian
- Department of Oncology, McGill University, Montreal, QC, Canada .,Segal Cancer Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
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35
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Sloan KE, Bohnsack MT. Unravelling the Mechanisms of RNA Helicase Regulation. Trends Biochem Sci 2018; 43:237-250. [PMID: 29486979 DOI: 10.1016/j.tibs.2018.02.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/28/2018] [Accepted: 02/01/2018] [Indexed: 12/22/2022]
Abstract
RNA helicases are critical regulators at the nexus of multiple pathways of RNA metabolism, and in the complex cellular environment, tight spatial and temporal regulation of their activity is essential. Dedicated protein cofactors play key roles in recruiting helicases to specific substrates and modulating their catalytic activity. Alongside individual RNA helicase cofactors, networks of cofactors containing evolutionarily conserved domains such as the G-patch and MIF4G domains highlight the potential for cross-regulation of different aspects of gene expression. Structural analyses of RNA helicase-cofactor complexes now provide insight into the diverse mechanisms by which cofactors can elicit specific and coordinated regulation of RNA helicase action. Furthermore, post-translational modifications (PTMs) and long non-coding RNA (lncRNA) regulators have recently emerged as novel modes of RNA helicase regulation.
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Affiliation(s)
- Katherine E Sloan
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Centre Göttingen, Humboldtallee 23, 37073 Göttingen, Germany; Göttingen Center for Molecular Biosciences, University of Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
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36
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Chantarachot T, Bailey-Serres J. Polysomes, Stress Granules, and Processing Bodies: A Dynamic Triumvirate Controlling Cytoplasmic mRNA Fate and Function. PLANT PHYSIOLOGY 2018; 176:254-269. [PMID: 29158329 PMCID: PMC5761823 DOI: 10.1104/pp.17.01468] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/17/2017] [Indexed: 05/05/2023]
Abstract
Discoveries illuminate highly regulated dynamics of mRNA translation, sequestration, and degradation within the cytoplasm of plants.
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Affiliation(s)
- Thanin Chantarachot
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Julia Bailey-Serres
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92521
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37
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A unique surface on Pat1 C-terminal domain directly interacts with Dcp2 decapping enzyme and Xrn1 5'-3' mRNA exonuclease in yeast. Proc Natl Acad Sci U S A 2017; 114:E9493-E9501. [PMID: 29078363 DOI: 10.1073/pnas.1711680114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The Pat1 protein is a central player of eukaryotic mRNA decay that has also been implicated in translational control. It is commonly considered a central platform responsible for the recruitment of several RNA decay factors. We demonstrate here that a yeast-specific C-terminal region from Pat1 interacts with several short motifs, named helical leucine-rich motifs (HLMs), spread in the long C-terminal region of yeast Dcp2 decapping enzyme. Structures of Pat1-HLM complexes reveal the basis for HLM recognition by Pat1. We also identify a HLM present in yeast Xrn1, the main 5'-3' exonuclease involved in mRNA decay. We show further that the ability of yeast Pat1 to bind HLMs is required for efficient growth and normal mRNA decay. Overall, our analyses indicate that yeast Pat1 uses a single binding surface to successively recruit several mRNA decay factors and show that interaction between those factors is highly polymorphic between species.
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38
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Numerous interactions act redundantly to assemble a tunable size of P bodies in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2017; 114:E9569-E9578. [PMID: 29078371 DOI: 10.1073/pnas.1712396114] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eukaryotic cells contain multiple RNA-protein assemblies referred to as RNP granules, which are thought to form through multiple protein-protein interactions analogous to a liquid-liquid phase separation. One class of RNP granules consists of P bodies, which consist of nontranslating mRNAs and the general translation repression and mRNA degradation machinery. P bodies have been suggested to form predominantly through interactions of Edc3 and a prion-like domain on Lsm4. In this work, we provide evidence that P-body assembly can be driven by multiple different protein-protein and/or protein-RNA interactions, including interactions involving Dhh1, Psp2, and Pby1. Moreover, the relative importance of specific interactions can vary with different growth conditions. Based on these observations, we develop a summative model wherein the P-body assembly phenotype of a given mutant can be predicted from the number of currently known protein-protein interactions between P-body components.
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39
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Götze M, Dufourt J, Ihling C, Rammelt C, Pierson S, Sambrani N, Temme C, Sinz A, Simonelig M, Wahle E. Translational repression of the Drosophila nanos mRNA involves the RNA helicase Belle and RNA coating by Me31B and Trailer hitch. RNA (NEW YORK, N.Y.) 2017; 23:1552-1568. [PMID: 28701521 PMCID: PMC5602113 DOI: 10.1261/rna.062208.117] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/10/2017] [Indexed: 05/10/2023]
Abstract
Translational repression of maternal mRNAs is an essential regulatory mechanism during early embryonic development. Repression of the Drosophila nanos mRNA, required for the formation of the anterior-posterior body axis, depends on the protein Smaug binding to two Smaug recognition elements (SREs) in the nanos 3' UTR. In a comprehensive mass spectrometric analysis of the SRE-dependent repressor complex, we identified Smaug, Cup, Me31B, Trailer hitch, eIF4E, and PABPC, in agreement with earlier data. As a novel component, the RNA-dependent ATPase Belle (DDX3) was found, and its involvement in deadenylation and repression of nanos was confirmed in vivo. Smaug, Cup, and Belle bound stoichiometrically to the SREs, independently of RNA length. Binding of Me31B and Tral was also SRE-dependent, but their amounts were proportional to the length of the RNA and equimolar to each other. We suggest that "coating" of the RNA by a Me31B•Tral complex may be at the core of repression.
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Affiliation(s)
- Michael Götze
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Jérémy Dufourt
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34396 Montpellier Cedex 5, France
| | - Christian Ihling
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Christiane Rammelt
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Stephanie Pierson
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34396 Montpellier Cedex 5, France
| | - Nagraj Sambrani
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34396 Montpellier Cedex 5, France
| | - Claudia Temme
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Andrea Sinz
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Martine Simonelig
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34396 Montpellier Cedex 5, France
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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40
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Loquacious-PD facilitates Drosophila Dicer-2 cleavage through interactions with the helicase domain and dsRNA. Proc Natl Acad Sci U S A 2017; 114:E7939-E7948. [PMID: 28874570 DOI: 10.1073/pnas.1707063114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Loquacious-PD (Loqs-PD) is required for biogenesis of many endogenous siRNAs in Drosophila In vitro, Loqs-PD enhances the rate of dsRNA cleavage by Dicer-2 and also enables processing of substrates normally refractory to cleavage. Using purified components, and Loqs-PD truncations, we provide a mechanistic basis for Loqs-PD functions. Our studies indicate that the 22 amino acids at the C terminus of Loqs-PD, including an FDF-like motif, directly interact with the Hel2 subdomain of Dicer-2's helicase domain. This interaction is RNA-independent, but we find that modulation of Dicer-2 cleavage also requires dsRNA binding by Loqs-PD. Furthermore, while the first dsRNA-binding motif of Loqs-PD is dispensable for enhancing cleavage of optimal substrates, it is essential for enhancing cleavage of suboptimal substrates. Finally, our studies define a previously unrecognized Dicer interaction interface and suggest that Loqs-PD is well positioned to recruit substrates into the helicase domain of Dicer-2.
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41
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Valkov E, Jonas S, Weichenrieder O. Mille viae in eukaryotic mRNA decapping. Curr Opin Struct Biol 2017; 47:40-51. [PMID: 28591671 DOI: 10.1016/j.sbi.2017.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 05/22/2017] [Indexed: 12/20/2022]
Abstract
Cellular mRNA levels are regulated via rates of transcription and decay. Since the removal of the mRNA 5'-cap by the decapping enzyme DCP2 is generally an irreversible step towards decay, it requires regulation. Control of DCP2 activity is likely effected by two interdependent means: by conformational control of the DCP2-DCP1 complex, and by assembly control of the decapping network, an array of mutually interacting effector proteins. Here, we compare three recent and conformationally distinct crystal structures of the DCP2-DCP1 decapping complex in the presence of substrate analogs and decapping enhancers and we discuss alternative substrate recognition modes for the catalytic domain of DCP2. Together with structure-based insight into decapping network assembly, we propose that DCP2-mediated decapping follows more than one path.
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Affiliation(s)
- Eugene Valkov
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Stefanie Jonas
- Institute of Biochemistry, ETH Zürich, Otto-Stern Weg 3, 8093 Zürich, Switzerland.
| | - Oliver Weichenrieder
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany.
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42
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Huang JH, Ku WC, Chen YC, Chang YL, Chu CY. Dual mechanisms regulate the nucleocytoplasmic localization of human DDX6. Sci Rep 2017; 7:42853. [PMID: 28216671 PMCID: PMC5316971 DOI: 10.1038/srep42853] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/18/2017] [Indexed: 12/14/2022] Open
Abstract
DDX6 is a conserved DEAD-box protein (DBP) that plays central roles in cytoplasmic RNA regulation, including processing body (P-body) assembly, mRNA decapping, and translational repression. Beyond its cytoplasmic functions, DDX6 may also have nuclear functions because its orthologues are known to localize to nuclei in several biological contexts. However, it is unclear whether DDX6 is generally present in human cell nuclei, and the molecular mechanism underlying DDX6 subcellular distribution remains elusive. In this study, we showed that DDX6 is commonly present in the nuclei of human-derived cells. Our structural and molecular analyses deviate from the current model that the shuttling of DDX6 is directly mediated by the canonical nuclear localization signal (NLS) and nuclear export signal (NES), which are recognized and transported by Importin-α/β and CRM1, respectively. Instead, we show that DDX6 can be transported by 4E-T in a piggyback manner. Furthermore, we provide evidence for a novel nuclear targeting mechanism in which DDX6 enters the newly formed nuclei by "hitch-hiking" on mitotic chromosomes with its C-terminal domain during M phase progression. Together, our results indicate that the nucleocytoplasmic localization of DDX6 is regulated by these dual mechanisms.
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Affiliation(s)
- Jo-Hsi Huang
- Department of Life Science, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
| | - Wei-Chi Ku
- School of Medicine, College of Medicine, Fu Jen Catholic University, New Taipei 24205, Taiwan
| | - Yen-Chun Chen
- Department of Life Science, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
| | - Yi-Ling Chang
- School of Medicine, College of Medicine, Fu Jen Catholic University, New Taipei 24205, Taiwan
| | - Chia-Ying Chu
- Department of Life Science, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
- Center for Systems Biology, National Taiwan University, Taipei 10617, Taiwan
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43
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Huch S, Müller M, Muppavarapu M, Gommlich J, Balagopal V, Nissan T. The decapping activator Edc3 and the Q/N-rich domain of Lsm4 function together to enhance mRNA stability and alter mRNA decay pathway dependence in Saccharomyces cerevisiae. Biol Open 2016; 5:1388-1399. [PMID: 27543059 PMCID: PMC5087693 DOI: 10.1242/bio.020487] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The rate and regulation of mRNA decay are major elements in the proper control of gene expression. Edc3 and Lsm4 are two decapping activator proteins that have previously been shown to function in the assembly of RNA granules termed P bodies. Here, we show that deletion of edc3, when combined with a removal of the glutamine/asparagine rich region of Lsm4 (edc3Δ lsm4ΔC) reduces mRNA stability and alters pathways of mRNA degradation. Multiple tested mRNAs exhibited reduced stability in the edc3Δ lsm4ΔC mutant. The destabilization was linked to an increased dependence on Ccr4-mediated deadenylation and mRNA decapping. Unlike characterized mutations in decapping factors that either are neutral or are able to stabilize mRNA, the combined edc3Δ lsm4ΔC mutant reduced mRNA stability. We characterized the growth and activity of the major mRNA decay systems and translation in double mutant and wild-type yeast. In the edc3Δ lsm4ΔC mutant, we observed alterations in the levels of specific mRNA decay factors as well as nuclear accumulation of the catalytic subunit of the decapping enzyme Dcp2. Hence, we suggest that the effects on mRNA stability in the edc3Δ lsm4ΔC mutant may originate from mRNA decay protein abundance or changes in mRNPs, or alternatively may imply a role for P bodies in mRNA stabilization. Summary: A strain mutated in two decapping activators, previously implicated in P body assembly, has reduced mRNA stability and increased dependence on decapping and Ccr4-dependent deadenylation for mRNA degradation.
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Affiliation(s)
- Susanne Huch
- Department of Molecular Biology, Umeå University, Umeå SE-901 87, Sweden
| | - Maren Müller
- Department of Molecular Biology, Umeå University, Umeå SE-901 87, Sweden
| | | | - Jessie Gommlich
- Department of Molecular Biology, Umeå University, Umeå SE-901 87, Sweden
| | - Vidya Balagopal
- Department of Molecular Biology, Umeå University, Umeå SE-901 87, Sweden
| | - Tracy Nissan
- Department of Molecular Biology, Umeå University, Umeå SE-901 87, Sweden
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44
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Mugler CF, Hondele M, Heinrich S, Sachdev R, Vallotton P, Koek AY, Chan LY, Weis K. ATPase activity of the DEAD-box protein Dhh1 controls processing body formation. eLife 2016; 5. [PMID: 27692063 PMCID: PMC5096884 DOI: 10.7554/elife.18746] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/28/2016] [Indexed: 12/22/2022] Open
Abstract
Translational repression and mRNA degradation are critical mechanisms of posttranscriptional gene regulation that help cells respond to internal and external cues. In response to certain stress conditions, many mRNA decay factors are enriched in processing bodies (PBs), cellular structures involved in degradation and/or storage of mRNAs. Yet, how cells regulate assembly and disassembly of PBs remains poorly understood. Here, we show that in budding yeast, mutations in the DEAD-box ATPase Dhh1 that prevent ATP hydrolysis, or that affect the interaction between Dhh1 and Not1, the central scaffold of the CCR4-NOT complex and an activator of the Dhh1 ATPase, prevent PB disassembly in vivo. Intriguingly, this process can be recapitulated in vitro, since recombinant Dhh1 and RNA, in the presence of ATP, phase-separate into liquid droplets that rapidly dissolve upon addition of Not1. Our results identify the ATPase activity of Dhh1 as a critical regulator of PB formation. DOI:http://dx.doi.org/10.7554/eLife.18746.001 Most cells and organisms live in changeable environments. Adapting to environmental changes means that organisms must quickly alter which of their genes they express. Varying which genes are switched on or off is not enough; cells must also degrade existing messenger RNAs (or mRNAs for short), which contain the genetic instructions of the previously active genes. Therefore, cells must tightly regulate the machinery needed to degrade mRNAs. When Baker’s yeast (also known as budding yeast) cells experience certain stressful conditions, the proteins that break down mRNAs localize into specific structures inside the cell known as ‘processing bodies’. These structures are found in many other organisms across evolution, from yeast to human. Processing bodies also form in a variety of biological contexts, such as in nerve cells and developing embryos. Still, why cells form processing bodies, and how their assembly is regulated, is not well understood. One essential component of processing bodies is an enzyme called Dhh1. This enzyme has been conserved throughout evolution and is known to promote the decay of mRNAs as well as to repress their translation into proteins. Now, Mugler, Hondele et al. show that Dhh1’s must break down molecules of the energy carrier ATP (referred to as its “ATPase activity”) in order to regulate the dynamic nature of processing bodies. Mutant Dhh1 proteins that lack ATPase activity form permanent processing bodies in non-stressed yeast cells. This shows that that the breakdown of ATP by Dhh1 is required for the disassembly of processing bodies. Similar results were seen for mutant Dhh1 proteins that cannot interact with Not1, a protein which enhances the ATPase activity of Dhh1. Next Mugler, Hondele et al. mixed purified Dhh1 with ATP and RNA molecules and saw that the mixture underwent a “liquid-liquid phase separation” and formed observable granules, similar to oil droplets in water. These granules dissolved when Not1 was added to stimulate the Dhh1 enzyme to turnover ATP. This showed that several important biochemical and biophysical aspects of processing bodies seen within living cells could be recreated outside of a cell. Armed with a greater understanding of the rules that govern the formation of processing bodies, future work can now address how important processing bodies are for regulating gene expression. Another challenge for the future will be to examine the specific roles that processing bodies play in yeast and other cells, like human egg cells or nerve cells. DOI:http://dx.doi.org/10.7554/eLife.18746.002
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Affiliation(s)
| | | | | | | | | | - Adriana Y Koek
- University of California, Berkeley, Berkeley, United States
| | - Leon Y Chan
- University of California, Berkeley, Berkeley, United States
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45
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Structure of the active form of Dcp1-Dcp2 decapping enzyme bound to m 7GDP and its Edc3 activator. Nat Struct Mol Biol 2016; 23:982-986. [PMID: 27694841 DOI: 10.1038/nsmb.3300] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/01/2016] [Indexed: 01/19/2023]
Abstract
Elimination of the 5' cap of eukaryotic mRNAs, known as decapping, is considered to be a crucial, irreversible and highly regulated step required for the rapid degradation of mRNA by Xrn1, the major cytoplasmic 5'-3' exonuclease. Decapping is accomplished by the recruitment of a protein complex formed by the Dcp2 catalytic subunit and its Dcp1 cofactor. However, this complex has a low intrinsic enzymatic activity and requires several accessory proteins such as the Lsm1-7 complex, Pat1, Edc1-Edc2 and/or Edc3 to be fully active. Here we present the crystal structure of the active form of the yeast Kluyveromyces lactis Dcp1-Dcp2 enzyme bound to its product (m7GDP) and its potent activator Edc3. This structure of the Dcp1-Dcp2 complex bound to a cap analog further explains previously published data on substrate binding and provides hints as to the mechanism of Edc3-mediated Dcp2 activation.
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46
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Kamenska A, Simpson C, Vindry C, Broomhead H, Bénard M, Ernoult-Lange M, Lee BP, Harries LW, Weil D, Standart N. The DDX6-4E-T interaction mediates translational repression and P-body assembly. Nucleic Acids Res 2016; 44:6318-34. [PMID: 27342281 PMCID: PMC5291280 DOI: 10.1093/nar/gkw565] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 06/10/2016] [Accepted: 06/14/2016] [Indexed: 12/13/2022] Open
Abstract
4E-Transporter binds eIF4E via its consensus sequence YXXXXLΦ, shared with eIF4G, and is a nucleocytoplasmic shuttling protein found enriched in P-(rocessing) bodies. 4E-T inhibits general protein synthesis by reducing available eIF4E levels. Recently, we showed that 4E-T bound to mRNA however represses its translation in an eIF4E-independent manner, and contributes to silencing of mRNAs targeted by miRNAs. Here, we address further the mechanism of translational repression by 4E-T by first identifying and delineating the interacting sites of its major partners by mass spectrometry and western blotting, including DDX6, UNR, unrip, PAT1B, LSM14A and CNOT4. Furthermore, we document novel binding between 4E-T partners including UNR-CNOT4 and unrip-LSM14A, altogether suggesting 4E-T nucleates a complex network of RNA-binding protein interactions. In functional assays, we demonstrate that joint deletion of two short conserved motifs that bind UNR and DDX6 relieves repression of 4E-T-bound mRNA, in part reliant on the 4E-T-DDX6-CNOT1 axis. We also show that the DDX6-4E-T interaction mediates miRNA-dependent translational repression and de novo P-body assembly, implying that translational repression and formation of new P-bodies are coupled processes. Altogether these findings considerably extend our understanding of the role of 4E-T in gene regulation, important in development and neurogenesis.
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Affiliation(s)
- Anastasiia Kamenska
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB21QW, UK
| | - Clare Simpson
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB21QW, UK
| | - Caroline Vindry
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB21QW, UK
| | - Helen Broomhead
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB21QW, UK
| | - Marianne Bénard
- Sorbonne Universités, UPMC, CNRS, IBPS, Developmental Biology Laboratory, 75005 Paris, France
| | - Michèle Ernoult-Lange
- Sorbonne Universités, UPMC, CNRS, IBPS, Developmental Biology Laboratory, 75005 Paris, France
| | - Benjamin P Lee
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Barrack Road, Exeter EX2 5DW
| | - Lorna W Harries
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Barrack Road, Exeter EX2 5DW
| | - Dominique Weil
- Sorbonne Universités, UPMC, CNRS, IBPS, Developmental Biology Laboratory, 75005 Paris, France
| | - Nancy Standart
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB21QW, UK
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47
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Ozgur S, Basquin J, Kamenska A, Filipowicz W, Standart N, Conti E. Structure of a Human 4E-T/DDX6/CNOT1 Complex Reveals the Different Interplay of DDX6-Binding Proteins with the CCR4-NOT Complex. Cell Rep 2015; 13:703-711. [DOI: 10.1016/j.celrep.2015.09.033] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/05/2015] [Accepted: 09/10/2015] [Indexed: 01/09/2023] Open
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48
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He F, Jacobson A. Control of mRNA decapping by positive and negative regulatory elements in the Dcp2 C-terminal domain. RNA (NEW YORK, N.Y.) 2015; 21:1633-47. [PMID: 26184073 PMCID: PMC4536323 DOI: 10.1261/rna.052449.115] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/08/2015] [Indexed: 05/23/2023]
Abstract
Decapping commits an mRNA to complete degradation and promotes general 5' to 3' decay, nonsense-mediated decay (NMD), and transcript-specific degradation. In Saccharomyces cerevisiae, a single decapping enzyme composed of a regulatory subunit (Dcp1) and a catalytic subunit (Dcp2) targets thousands of distinct substrate mRNAs. However, the mechanisms controlling this enzyme's in vivo activity and substrate specificity remain elusive. Here, using a genetic approach, we show that the large C-terminal domain of Dcp2 includes a set of conserved negative and positive regulatory elements. A single negative element inhibits enzymatic activity and controls the downstream functions of several positive elements. The positive elements recruit the specific decapping activators Edc3, Pat1, and Upf1 to form distinct decapping complexes and control the enzyme's substrate specificity and final activation. Our results reveal unforeseen regulatory mechanisms that control decapping enzyme activity and function in vivo, and define roles for several decapping activators in the regulation of mRNA decapping.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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49
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Hrle A, Maier LK, Sharma K, Ebert J, Basquin C, Urlaub H, Marchfelder A, Conti E. Structural analyses of the CRISPR protein Csc2 reveal the RNA-binding interface of the type I-D Cas7 family. RNA Biol 2015; 11:1072-82. [PMID: 25483036 PMCID: PMC4615900 DOI: 10.4161/rna.29893] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Upon pathogen invasion, bacteria and archaea activate an RNA-interference-like mechanism termed CRISPR (clustered regularly interspaced short palindromic repeats). A large family of Cas (CRISPR-associated) proteins mediates the different stages of this sophisticated immune response. Bioinformatic studies have classified the Cas proteins into families, according to their sequences and respective functions. These range from the insertion of the foreign genetic elements into the host genome to the activation of the interference machinery as well as target degradation upon attack. Cas7 family proteins are central to the type I and type III interference machineries as they constitute the backbone of the large interference complexes. Here we report the crystal structure of Thermofilum pendens Csc2, a Cas7 family protein of type I-D. We found that Csc2 forms a core RRM-like domain, flanked by three peripheral insertion domains: a lid domain, a Zinc-binding domain and a helical domain. Comparison with other Cas7 family proteins reveals a set of similar structural features both in the core and in the peripheral domains, despite the absence of significant sequence similarity. T. pendens Csc2 binds single-stranded RNA in vitro in a sequence-independent manner. Using a crosslinking - mass-spectrometry approach, we mapped the RNA-binding surface to a positively charged surface patch on T. pendens Csc2. Thus our analysis of the key structural and functional features of T. pendens Csc2 highlights recurring themes and evolutionary relationships in type I and type III Cas proteins.
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Key Words
- CRISPR
- CRISPR, Clustered regulatory short interspaced palindromic repeats
- Cas, CRISPR-associated
- Cas7
- H1 and H2 and H1-2, β-hairpins of insertion domain 1 (or lid domain)
- Mk, Methanopyrus kandleri
- RAMP, Repeat associated mysterious protein
- RNA binding
- RNAi, RNA interference
- RRM domain
- RRM, RNA recognition motif
- Rmsd, Root mean square deviation
- SAD, Single-wavelength anomalous dispersion
- Ss, Sulfolobus solfataricus
- Tp, Thermofilum pendens
- crRNA, CRISPR RNA
- dCASCADE, interference complex subtype I-D
- eCASCADE, interference complex subtype I-E
- prokaryotic immune system
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Affiliation(s)
- Ajla Hrle
- a Structural Cell Biology Department; Max Planck Institute of Biochemistry ; Martinsried , Germany
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50
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Ayache J, Bénard M, Ernoult-Lange M, Minshall N, Standart N, Kress M, Weil D. P-body assembly requires DDX6 repression complexes rather than decay or Ataxin2/2L complexes. Mol Biol Cell 2015; 26:2579-95. [PMID: 25995375 PMCID: PMC4501357 DOI: 10.1091/mbc.e15-03-0136] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 05/13/2015] [Accepted: 05/13/2015] [Indexed: 01/04/2023] Open
Abstract
P-bodies are cytoplasmic ribonucleoprotein granules involved in posttranscriptional regulation. DDX6 is a key component of their assembly in human cells. This DEAD-box RNA helicase is known to be associated with various complexes, including the decapping complex, the CPEB repression complex, RISC, and the CCR4/NOT complex. To understand which DDX6 complexes are required for P-body assembly, we analyzed the DDX6 interactome using the tandem-affinity purification methodology coupled to mass spectrometry. Three complexes were prominent: the decapping complex, a CPEB-like complex, and an Ataxin2/Ataxin2L complex. The exon junction complex was also found, suggesting DDX6 binding to newly exported mRNAs. Finally, some DDX6 was associated with polysomes, as previously reported in yeast. Despite its high enrichment in P-bodies, most DDX6 is localized out of P-bodies. Of the three complexes, only the decapping and CPEB-like complexes were recruited into P-bodies. Investigation of P-body assembly in various conditions allowed us to distinguish required proteins from those that are dispensable or participate only in specific conditions. Three proteins were required in all tested conditions: DDX6, 4E-T, and LSM14A. These results reveal the variety of pathways of P-body assembly, which all nevertheless share three key factors connecting P-body assembly to repression.
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Affiliation(s)
- Jessica Ayache
- UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France
| | - Marianne Bénard
- UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France
| | - Michèle Ernoult-Lange
- UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France
| | - Nicola Minshall
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Nancy Standart
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Michel Kress
- UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France
| | - Dominique Weil
- UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France
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