1
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Zhou F, Bocetti JM, Hou M, Qin D, Hinnebusch AG, Lorsch JR. Transcriptome-wide analysis of the function of Ded1 in translation preinitiation complex assembly in a reconstituted in vitro system. eLife 2024; 13:RP93255. [PMID: 38573742 PMCID: PMC10994665 DOI: 10.7554/elife.93255] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
We have developed a deep sequencing-based approach, Rec-Seq, that allows simultaneous monitoring of ribosomal 48S preinitiation complex (PIC) formation on every mRNA in the translatome in an in vitro reconstituted system. Rec-Seq isolates key early steps in translation initiation in the absence of all other cellular components and processes. Using this approach, we show that the DEAD-box ATPase Ded1 promotes 48S PIC formation on the start codons of >1000 native mRNAs, most of which have long, structured 5'-untranslated regions (5'UTRs). Remarkably, initiation measured in Rec-Seq was enhanced by Ded1 for most mRNAs previously shown to be highly Ded1-dependent by ribosome profiling of ded1 mutants in vivo, demonstrating that the core translation functions of the factor are recapitulated in the purified system. Our data do not support a model in which Ded1acts by reducing initiation at alternative start codons in 5'UTRs and instead indicate it functions by directly promoting mRNA recruitment to the 43S PIC and scanning to locate the main start codon. We also provide evidence that eIF4A, another essential DEAD-box initiation factor, is required for efficient PIC assembly on almost all mRNAs, regardless of their structural complexity, in contrast to the preferential stimulation by Ded1 of initiation on mRNAs with long, structured 5'UTRs.
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Affiliation(s)
- Fujun Zhou
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentBethesdaUnited States
| | - Julie M Bocetti
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentBethesdaUnited States
| | - Meizhen Hou
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentBethesdaUnited States
| | - Daoming Qin
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentBethesdaUnited States
| | - Alan G Hinnebusch
- Section on Nutrient Control of Gene Expression, Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentBethesdaUnited States
| | - Jon R Lorsch
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentBethesdaUnited States
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2
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Zhou F, Bocetti JM, Hou M, Qin D, Hinnebusch AG, Lorsch JR. Transcriptome-wide analysis of the function of Ded1 in translation preinitiation complex assembly in a reconstituted in vitro system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.16.562452. [PMID: 37986768 PMCID: PMC10659408 DOI: 10.1101/2023.10.16.562452] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
We have developed a deep sequencing-based approach, Rec-Seq, that allows simultaneous monitoring of ribosomal 48S pre-initiation complex (PIC) formation on every mRNA in the translatome in an in vitro reconstituted system. Rec-Seq isolates key early steps in translation initiation in the absence of all other cellular components and processes. Using this approach we show that the DEAD-box ATPase Ded1 promotes 48S PIC formation on the start codons of >1000 native mRNAs, most of which have long, structured 5'-untranslated regions (5'UTRs). Remarkably, initiation measured in Rec-Seq was enhanced by Ded1 for most mRNAs previously shown to be highly Ded1-dependent by ribosome profiling of ded1 mutants in vivo, demonstrating that the core translation functions of the factor are recapitulated in the purified system. Our data do not support a model in which Ded1acts by reducing initiation at alternative start codons in 5'UTRs and instead indicate it functions by directly promoting mRNA recruitment to the 43S PIC and scanning to locate the main start codon. We also provide evidence that eIF4A, another essential DEAD-box initiation factor, is required for efficient PIC assembly on almost all mRNAs, regardless of their structural complexity, in contrast to the preferential stimulation by Ded1 of initiation on mRNAs with long, structured 5'UTRs.
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Affiliation(s)
- Fujun Zhou
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Julie M Bocetti
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Meizhen Hou
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Daoming Qin
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
- Section on Nutrient Control of Gene Expression, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Alan G Hinnebusch
- Section on Nutrient Control of Gene Expression, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Jon R Lorsch
- Section on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
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3
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Tidu A, Martin F. The interplay between cis- and trans-acting factors drives selective mRNA translation initiation in eukaryotes. Biochimie 2024; 217:20-30. [PMID: 37741547 DOI: 10.1016/j.biochi.2023.09.017] [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: 05/04/2023] [Revised: 07/20/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023]
Abstract
Translation initiation consists in the assembly of the small and large ribosomal subunits on the start codon. This important step directly modulates the general proteome in living cells. Recently, genome wide studies revealed unexpected translation initiation events from unsuspected novel open reading frames resulting in the synthesis of a so-called 'dark proteome'. Indeed, the identification of the start codon by the translation machinery is a critical step that defines the translational landscape of the cell. Therefore, translation initiation is a highly regulated process in all organisms. In this review, we focus on the various cis- and trans-acting factors that rule the regulation of translation initiation in eukaryotes. Recent discoveries have shown that the guidance of the translation machinery for the choice of the start codon require sophisticated molecular mechanisms. In particular, the 5'UTR and the coding sequences contain cis-acting elements that trigger the use of AUG codons but also non-AUG codons to initiate protein synthesis. The use of these alternative start codons is also largely influenced by numerous trans-acting elements that drive selective mRNA translation in response to environmental changes.
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Affiliation(s)
- Antonin Tidu
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France
| | - Franck Martin
- Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, 2, allée Konrad Roentgen, F-67084 Strasbourg, France.
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4
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Zhang F, Sen ND, Hinnebusch AG. Repression of MRP51 in cis does not contribute to the synthetic growth defect conferred by an hphMX4-marked deletion of DBP1 in a ded1-ts mutant. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.578007. [PMID: 38410469 PMCID: PMC10896344 DOI: 10.1101/2024.01.30.578007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Powers et al. recently demonstrated that the hphMX6 cassette used to delete DPB1 in dbp1Δ::hphMX6 yeast mutants leads to reduced expression in cis of the adjacent gene MRP51, encoding the mitochondrial small subunit (SSU) ribosomal protein Mrp51. Here we provide evidence that elimination of Dbp1, not reduced MRP51 expression, underlies the synthetic growth defect of a dbp1Δ::hphMX6 ded1-ts mutant on glucose-containing medium, where respiration is dispensable, consistent with our previous conclusion that Dbp1 and Ded1 perform overlapping functions in stimulating translation initiation on mRNAs burdened with long or structured 5'UTRs in cells cultured with glucose.
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Affiliation(s)
- Fan Zhang
- Division of Molecular and Cellular Biology, Eunice K. Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Neelam Dabas Sen
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Alan G. Hinnebusch
- Division of Molecular and Cellular Biology, Eunice K. Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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5
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Powers EN, Kuwayama N, Sousa C, Reynaud K, Jovanovic M, Ingolia NT, Brar GA. Dbp1 is a low performance paralog of RNA helicase Ded1 that drives impaired translation and heat stress response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.575095. [PMID: 38260653 PMCID: PMC10802583 DOI: 10.1101/2024.01.12.575095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Ded1 and Dbp1 are paralogous conserved RNA helicases that enable translation initiation in yeast. Ded1 has been heavily studied but the role of Dbp1 is poorly understood. We find that the expression of these two helicases is controlled in an inverse and condition-specific manner. In meiosis and other long-term starvation states, Dbp1 expression is upregulated and Ded1 is downregulated, whereas in mitotic cells, Dbp1 expression is extremely low. Inserting the DBP1 ORF in place of the DED1 ORF cannot replace the function of Ded1 in supporting translation, partly due to inefficient mitotic translation of the DBP1 mRNA, dependent on features of its ORF sequence but independent of codon optimality. Global measurements of translation rates and 5' leader translation, activity of mRNA-tethered helicases, ribosome association, and low temperature growth assays show that-even at matched protein levels-Ded1 is more effective than Dbp1 at activating translation, especially for mRNAs with structured 5' leaders. Ded1 supports halting of translation and cell growth in response to heat stress, but Dbp1 lacks this function, as well. These functional differences in the ability to efficiently mediate translation activation and braking can be ascribed to the divergent, disordered N- and C-terminal regions of these two helicases. Altogether, our data show that Dbp1 is a "low performance" version of Ded1 that cells employ in place of Ded1 under long-term conditions of nutrient deficiency.
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6
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Gentry RC, Ide NA, Comunale VM, Hartwick EW, Kinz-Thompson CD, Gonzalez RL. The mechanism of mRNA activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.567265. [PMID: 38014128 PMCID: PMC10680758 DOI: 10.1101/2023.11.15.567265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
During translation initiation, messenger RNA molecules must be identified and activated for loading into a ribosome. In this rate-limiting step, the heterotrimeric protein eukaryotic initiation factor eIF4F must recognize and productively interact with the 7-methylguanosine cap at the 5' end of the messenger RNA and subsequently activate the message. Despite its fundamental, regulatory role in gene expression, the molecular events underlying cap recognition and messenger RNA activation remain mysterious. Here, we generate a unique, single-molecule fluorescence imaging system to interrogate the dynamics with which eIF4F discriminates productive and non-productive locations on full-length, native messenger RNA molecules. At the single-molecule level, we observe stochastic sampling of eIF4F along the length of the messenger RNA and identify allosteric communication between the eIF4F subunits which ultimately drive cap-recognition and subsequent activation of the message. Our experiments uncover novel functions for each subunit of eIF4F and we conclude by presenting a model for messenger RNA activation which precisely defines the composition of the activated message. This model provides a general framework for understanding how messenger RNA molecules may be discriminated from one another, and how other RNA-binding proteins may control the efficiency of translation initiation.
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Affiliation(s)
- Riley C Gentry
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Nicholas A Ide
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | - Erik W Hartwick
- Department of Chemistry, Columbia University, New York, NY, USA
- Current Address: BioChemistry Krios Electron Microscopy Facility, Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Colin D Kinz-Thompson
- Department of Chemistry, Columbia University, New York, NY, USA
- Current Address: Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102
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7
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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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8
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Wery M, Szachnowski U, Andjus S, de Andres-Pablo A, Morillon A. The RNA helicases Dbp2 and Mtr4 regulate the expression of Xrn1-sensitive long non-coding RNAs in yeast. FRONTIERS IN RNA RESEARCH 2023; 1:1244554. [PMID: 37667796 PMCID: PMC7615016 DOI: 10.3389/frnar.2023.1244554] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
The expression of yeast long non-coding (lnc)RNAs is restricted by RNA surveillance machineries, including the cytoplasmic 5'-3' exonuclease Xrn1 which targets a conserved family of lncRNAs defined as XUTs, and that are mainly antisense to protein-coding genes. However, the co-factors involved in the degradation of these transcripts and the underlying molecular mechanisms remain largely unknown. Here, we show that two RNA helicases, Dbp2 and Mtr4, act as global regulators of XUTs expression. Using RNA-Seq, we found that most of them accumulate upon Dbp2 inactivation or Mtr4 depletion. Mutants of the cytoplasmic RNA helicases Ecm32, Ski2, Slh1, Dbp1, and Dhh1 did not recapitulate this global stabilization of XUTs, suggesting that XUTs decay is specifically controlled by Dbp2 and Mtr4. Notably, Dbp2 and Mtr4 affect XUTs independently of their configuration relative to their paired-sense mRNAs. Finally, we show that the effect of Dbp2 on XUTs depends on a cytoplasmic localization. Overall, our data indicate that Dbp2 and Mtr4 are global regulators of lncRNAs expression and contribute to shape the non-coding transcriptome together with RNA decay machineries.
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Affiliation(s)
- Maxime Wery
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
| | - Ugo Szachnowski
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
| | - Sara Andjus
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, PSL
University, Sorbonne Université, CNRS UMR3244, Paris Cedex, France
| | - Alvaro de Andres-Pablo
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
| | - Antonin Morillon
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
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9
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O'Sullivan MH, Fraser CS. Monitoring RNA restructuring in a human cell-free extract reveals eIF4A-dependent and eIF4A-independent unwinding activity. J Biol Chem 2023:104936. [PMID: 37331603 PMCID: PMC10362145 DOI: 10.1016/j.jbc.2023.104936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 06/20/2023] Open
Abstract
The canonical DEAD-box helicase, eIF4A, unwinds 5' UTR secondary structures to promote mRNA translation initiation. Growing evidence has indicated that other helicases, such as DHX29 and DDX3/ded1p, also function to promote the scanning of the 40S subunit on highly structured mRNAs. It is unknown how the relative contributions of eIF4A and other helicases regulate duplex unwinding on an mRNA to promote initiation. Here, we have adapted a real-time fluorescent duplex unwinding assay to monitor precisely helicase activity in the 5' UTR of a reporter mRNA that can be translated in a cell-free extract in parallel. We monitored the rate of 5' UTR-dependent duplex unwinding in the absence or presence of an eIF4A inhibitor (Hippuristanol), a dominant negative eIF4A (eIF4A-R362Q), or a mutant eIF4E (eIF4E-W73L) that can bind the m7G cap but not eIF4G. Our experiments reveal that the duplex unwinding activity in the cell-free extract is roughly evenly split between eIF4A-dependent and eIF4A-independent mechanisms. Importantly, we show that the robust eIF4A-independent duplex unwinding is not sufficient for translation. We also show that the m7G cap structure, and not the poly(A) tail, is the primary mRNA modification responsible for promoting duplex unwinding in our cell-free extract system. Overall, the fluorescent duplex unwinding assay provides a precise method to investigate how eIF4A-dependent and eIF4A-independent helicase activity regulates translation initiation in cell-free extracts. We anticipate that potential small molecule inhibitors could be tested for helicase inhibition using this duplex unwinding assay.
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Affiliation(s)
- Mattie H O'Sullivan
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616
| | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616.
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10
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Kito Y, Matsumoto A, Ichihara K, Shiraishi C, Tang R, Hatano A, Matsumoto M, Han P, Iwasaki S, Nakayama KI. The ASC-1 complex promotes translation initiation by scanning ribosomes. EMBO J 2023; 42:e112869. [PMID: 37092320 PMCID: PMC10267693 DOI: 10.15252/embj.2022112869] [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: 10/19/2022] [Revised: 03/18/2023] [Accepted: 03/27/2023] [Indexed: 04/25/2023] Open
Abstract
Translation initiates when the eIF4F complex binds the 5' mRNA cap, followed by 5' untranslated region scanning for the start codon by scanning ribosomes. Here, we demonstrate that the ASC-1 complex (ASCC), which was previously shown to promote the dissociation of colliding 80S ribosomes, associates with scanning ribosomes to regulate translation initiation. Selective translation complex profiling (TCP-seq) analysis revealed that ASCC3, a helicase domain-containing subunit of ASCC, localizes predominantly to the 5' untranslated region of mRNAs. Ribo-seq, TCP-seq, and luciferase reporter analyses showed that ASCC3 knockdown impairs 43S preinitiation complex loading and scanning dynamics, thereby reducing translation efficiency. Whereas eIF4A, an RNA helicase in the eIF4F complex, is important for global translation, ASCC was found to regulate the scanning process for a specific subset of transcripts. Our results have thus revealed that ASCC is required not only for dissociation of colliding 80S ribosomes but also for efficient translation initiation by scanning ribosomes at a subset of transcripts.
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Affiliation(s)
- Yuki Kito
- Division of Cell Biology, Medical Institute of BioregulationKyushu UniversityFukuokaJapan
| | - Akinobu Matsumoto
- Division of Cell Biology, Medical Institute of BioregulationKyushu UniversityFukuokaJapan
| | - Kazuya Ichihara
- Division of Cell Biology, Medical Institute of BioregulationKyushu UniversityFukuokaJapan
| | - Chisa Shiraishi
- Division of Cell Biology, Medical Institute of BioregulationKyushu UniversityFukuokaJapan
| | - Ronghao Tang
- Division of Cell Biology, Medical Institute of BioregulationKyushu UniversityFukuokaJapan
| | - Atsushi Hatano
- Department of Omics and Systems BiologyGraduate School of Medical and Dental Sciences, Niigata UniversityNiigataJapan
| | - Masaki Matsumoto
- Department of Omics and Systems BiologyGraduate School of Medical and Dental Sciences, Niigata UniversityNiigataJapan
| | - Peixun Han
- RNA Systems Biochemistry LaboratoryRIKEN Cluster for Pioneering ResearchWakoJapan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier SciencesThe University of TokyoKashiwaJapan
| | - Shintaro Iwasaki
- RNA Systems Biochemistry LaboratoryRIKEN Cluster for Pioneering ResearchWakoJapan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier SciencesThe University of TokyoKashiwaJapan
| | - Keiichi I Nakayama
- Division of Cell Biology, Medical Institute of BioregulationKyushu UniversityFukuokaJapan
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11
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May GE, Akirtava C, Agar-Johnson M, Micic J, Woolford J, McManus J. Unraveling the influences of sequence and position on yeast uORF activity using massively parallel reporter systems and machine learning. eLife 2023; 12:e69611. [PMID: 37227054 PMCID: PMC10259493 DOI: 10.7554/elife.69611] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/24/2023] [Indexed: 05/26/2023] Open
Abstract
Upstream open-reading frames (uORFs) are potent cis-acting regulators of mRNA translation and nonsense-mediated decay (NMD). While both AUG- and non-AUG initiated uORFs are ubiquitous in ribosome profiling studies, few uORFs have been experimentally tested. Consequently, the relative influences of sequence, structural, and positional features on uORF activity have not been determined. We quantified thousands of yeast uORFs using massively parallel reporter assays in wildtype and ∆upf1 yeast. While nearly all AUG uORFs were robust repressors, most non-AUG uORFs had relatively weak impacts on expression. Machine learning regression modeling revealed that both uORF sequences and locations within transcript leaders predict their effect on gene expression. Indeed, alternative transcription start sites highly influenced uORF activity. These results define the scope of natural uORF activity, identify features associated with translational repression and NMD, and suggest that the locations of uORFs in transcript leaders are nearly as predictive as uORF sequences.
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Affiliation(s)
- Gemma E May
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Christina Akirtava
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Matthew Agar-Johnson
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Jelena Micic
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - John Woolford
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
| | - Joel McManus
- Department of Biological Sciences, Carnegie Mellon UniversityPittsburghUnited States
- Computational Biology Department, Carnegie Mellon UniversityPittsburghUnited States
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12
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Powers EN, Chan C, Doron-Mandel E, Llacsahuanga Allcca L, Kim Kim J, Jovanovic M, Brar GA. Bidirectional promoter activity from expression cassettes can drive off-target repression of neighboring gene translation. eLife 2022; 11:e81086. [PMID: 36503721 PMCID: PMC9754628 DOI: 10.7554/elife.81086] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022] Open
Abstract
Targeted selection-based genome-editing approaches have enabled many fundamental discoveries and are used routinely with high precision. We found, however, that replacement of DBP1 with a common selection cassette in budding yeast led to reduced expression and function for the adjacent gene, MRP51, despite all MRP51 coding and regulatory sequences remaining intact. Cassette-induced repression of MRP51 drove all mutant phenotypes detected in cells deleted for DBP1. This behavior resembled the 'neighboring gene effect' (NGE), a phenomenon of unknown mechanism whereby cassette insertion at one locus reduces the expression of a neighboring gene. Here, we leveraged strong off-target mutant phenotypes resulting from cassette replacement of DBP1 to provide mechanistic insight into the NGE. We found that the inherent bidirectionality of promoters, including those in expression cassettes, drives a divergent transcript that represses MRP51 through combined transcriptional interference and translational repression mediated by production of a long undecoded transcript isoform (LUTI). Divergent transcript production driving this off-target effect is general to yeast expression cassettes and occurs ubiquitously with insertion. Despite this, off-target effects are often naturally prevented by local sequence features, such as those that terminate divergent transcripts between the site of cassette insertion and the neighboring gene. Thus, cassette-induced off-target effects can be eliminated by the insertion of transcription terminator sequences into the cassette, flanking the promoter. Because the driving features of this off-target effect are broadly conserved, our study suggests it should be considered in the design and interpretation of experiments using integrated expression cassettes in other eukaryotic systems, including human cells.
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Affiliation(s)
- Emily Nicole Powers
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Charlene Chan
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Ella Doron-Mandel
- Department of Biological Sciences, Columbia UniversityNew YorkUnited States
| | | | - Jenny Kim Kim
- Department of Biological Sciences, Columbia UniversityNew YorkUnited States
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia UniversityNew YorkUnited States
| | - Gloria Ann Brar
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkleyBerkleyUnited States
- Center for Computational Biology, University of California, BerkeleyBerkeleyUnited States
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Ryan CS, Schröder M. The human DEAD-box helicase DDX3X as a regulator of mRNA translation. Front Cell Dev Biol 2022; 10:1033684. [PMID: 36393867 PMCID: PMC9642913 DOI: 10.3389/fcell.2022.1033684] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/07/2022] [Indexed: 08/27/2023] Open
Abstract
The human DEAD-box protein DDX3X is an RNA remodelling enzyme that has been implicated in various aspects of RNA metabolism. In addition, like many DEAD-box proteins, it has non-conventional functions that are independent of its enzymatic activity, e.g., DDX3X acts as an adaptor molecule in innate immune signalling pathways. DDX3X has been linked to several human diseases. For example, somatic mutations in DDX3X were identified in various human cancers, and de novo germline mutations cause a neurodevelopmental condition now termed 'DDX3X syndrome'. DDX3X is also an important host factor in many different viral infections, where it can have pro-or anti-viral effects depending on the specific virus. The regulation of translation initiation for specific mRNA transcripts is likely a central cellular function of DDX3X, yet many questions regarding its exact targets and mechanisms of action remain unanswered. In this review, we explore the current knowledge about DDX3X's physiological RNA targets and summarise its interactions with the translation machinery. A role for DDX3X in translational reprogramming during cellular stress is emerging, where it may be involved in the regulation of stress granule formation and in mediating non-canonical translation initiation. Finally, we also discuss the role of DDX3X-mediated translation regulation during viral infections. Dysregulation of DDX3X's function in mRNA translation likely contributes to its involvement in disease pathophysiology. Thus, a better understanding of its exact mechanisms for regulating translation of specific mRNA targets is important, so that we can potentially develop therapeutic strategies for overcoming the negative effects of its dysregulation.
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14
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Liu X, Moshiri H, He Q, Sahoo A, Walker SE. Deletion of the N-Terminal Domain of Yeast Eukaryotic Initiation Factor 4B Reprograms Translation and Reduces Growth in Urea. Front Mol Biosci 2022; 8:787781. [PMID: 35047555 PMCID: PMC8762332 DOI: 10.3389/fmolb.2021.787781] [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: 10/01/2021] [Accepted: 12/03/2021] [Indexed: 11/24/2022] Open
Abstract
The yeast eukaryotic initiation factor 4B binds the 40S subunit in translation preinitiation complexes (PICs), promoting mRNA recruitment. Recent evidence indicates yeast mRNAs have variable dependence on eIF4B under optimal growth conditions. Given the ability of eIF4B to promote translation as a function of nutrient conditions in mammalian cells, we wondered if eIF4B activities in translation could alter phenotypes in yeast through differential mRNA selection for translation. Here we compared the effects of disrupting yeast eIF4B RNA- and 40S-binding motifs under ∼1400 growth conditions. The RNA-Recognition Motif (RRM) was dispensable for stress responses, but the 40S-binding N-terminal Domain (NTD) promoted growth in response to stressors requiring robust cellular integrity. In particular, the NTD conferred a strong growth advantage in the presence of urea, which may be important for pathogenesis of related fungal species. Ribosome profiling indicated that similar to complete eIF4B deletion, deletion of the NTD dramatically reduced translation, particularly of those mRNAs with long and highly structured 5-prime untranslated regions. This behavior was observed both with and without urea exposure, but the specific mRNA pool associated with ribosomes in response to urea differed. Deletion of the NTD led to relative increases in ribosome association of shorter transcripts with higher dependence on eIF4G, as was noted previously for eIF4B deletion. Gene ontology analysis indicated that proteins encoded by eIF4B NTD-dependent transcripts were associated with the cellular membrane system and the cell wall, while NTD-independent transcripts encoded proteins associated with cytoplasmic proteins and protein synthesis. This analysis highlighted the difference in structure content of mRNAs encoding membrane versus cytoplasmic housekeeping proteins and the variable reliance of specific gene ontology classes on various initiation factors promoting otherwise similar functions. Together our analyses suggest that deletion of the eIF4B NTD prevents cellular stress responses by affecting the capacity to translate a diverse mRNA pool.
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Affiliation(s)
- Xiaozhuo Liu
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Houtan Moshiri
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Qian He
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Ansuman Sahoo
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
| | - Sarah E Walker
- Department of Biological Sciences, SUNY at Buffalo, Buffalo, NY, United States
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15
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Stanciu A, Luo J, Funes L, Galbokke Hewage S, Kulkarni SD, Aitken CE. eIF3 and Its mRNA-Entry-Channel Arm Contribute to the Recruitment of mRNAs With Long 5′-Untranslated Regions. Front Mol Biosci 2022; 8:787664. [PMID: 35087868 PMCID: PMC8787345 DOI: 10.3389/fmolb.2021.787664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/13/2021] [Indexed: 01/21/2023] Open
Abstract
Translation initiation in eukaryotes is a multi-step pathway and the most regulated phase of translation. Eukaryotic initiation factor 3 (eIF3) is the largest and most complex of the translation initiation factors, and it contributes to events throughout the initiation pathway. In particular, eIF3 appears to play critical roles in mRNA recruitment. More recently, eIF3 has been implicated in driving the selective translation of specific classes of mRNAs. However, unraveling the mechanism of these diverse contributions—and disentangling the roles of the individual subunits of the eIF3 complex—remains challenging. We employed ribosome profiling of budding yeast cells expressing two distinct mutations targeting the eIF3 complex. These mutations either disrupt the entire complex or subunits positioned near the mRNA-entry channel of the ribosome and which appear to relocate during or in response to mRNA binding and start-codon recognition. Disruption of either the entire eIF3 complex or specific targeting of these subunits affects mRNAs with long 5′-untranslated regions and whose translation is more dependent on eIF4A, eIF4B, and Ded1 but less dependent on eIF4G, eIF4E, and PABP. Disruption of the entire eIF3 complex further affects mRNAs involved in mitochondrial processes and with structured 5′-untranslated regions. Comparison of the suite of mRNAs most sensitive to both mutations with those uniquely sensitive to disruption of the entire complex sheds new light on the specific roles of individual subunits of the eIF3 complex.
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Affiliation(s)
- Andrei Stanciu
- Computer Science Department, Vassar College, Poughkeepsie, NY, United States
| | - Juncheng Luo
- Biochemistry Program, Vassar College, Poughkeepsie, NY, United States
| | - Lucy Funes
- Biology Department, Vassar College, Poughkeepsie, NY, United States
| | | | - Shardul D. Kulkarni
- Department of Biochemistry and Molecular Biology, Penn State Eberly College of Medicine, University Park, PA, United States
| | - Colin Echeverría Aitken
- Biochemistry Program, Vassar College, Poughkeepsie, NY, United States
- Biology Department, Vassar College, Poughkeepsie, NY, United States
- *Correspondence: Colin Echeverría Aitken,
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16
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Down-Regulation of Yeast Helicase Ded1 by Glucose Starvation or Heat-Shock Differentially Impairs Translation of Ded1-Dependent mRNAs. Microorganisms 2021; 9:microorganisms9122413. [PMID: 34946015 PMCID: PMC8706886 DOI: 10.3390/microorganisms9122413] [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: 10/04/2021] [Revised: 11/18/2021] [Accepted: 11/18/2021] [Indexed: 12/14/2022] Open
Abstract
Ded1 is an essential DEAD-box helicase in yeast that broadly stimulates translation initiation and is critical for mRNAs with structured 5′UTRs. Recent evidence suggests that the condensation of Ded1 in mRNA granules down-regulates Ded1 function during heat-shock and glucose starvation. We examined this hypothesis by determining the overlap between mRNAs whose relative translational efficiencies (TEs), as determined by ribosomal profiling, were diminished in either stressed WT cells or in ded1 mutants examined in non-stress conditions. Only subsets of the Ded1-hyperdependent mRNAs identified in ded1 mutant cells exhibited strong TE reductions in glucose-starved or heat-shocked WT cells, and those down-regulated by glucose starvation also exhibited hyper-dependence on initiation factor eIF4B, and to a lesser extent eIF4A, for efficient translation in non-stressed cells. These findings are consistent with recent proposals that the dissociation of Ded1 from mRNA 5′UTRs and the condensation of Ded1 contribute to reduced Ded1 function during stress, and they further suggest that the down-regulation of eIF4B and eIF4A functions also contributes to the translational impairment of a select group of Ded1 mRNA targets with heightened dependence on all three factors during glucose starvation.
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17
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Witte F, Ruiz-Orera J, Mattioli CC, Blachut S, Adami E, Schulz JF, Schneider-Lunitz V, Hummel O, Patone G, Mücke MB, Šilhavý J, Heinig M, Bottolo L, Sanchis D, Vingron M, Chekulaeva M, Pravenec M, Hubner N, van Heesch S. A trans locus causes a ribosomopathy in hypertrophic hearts that affects mRNA translation in a protein length-dependent fashion. Genome Biol 2021; 22:191. [PMID: 34183069 PMCID: PMC8240307 DOI: 10.1186/s13059-021-02397-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 06/02/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Little is known about the impact of trans-acting genetic variation on the rates with which proteins are synthesized by ribosomes. Here, we investigate the influence of such distant genetic loci on the efficiency of mRNA translation and define their contribution to the development of complex disease phenotypes within a panel of rat recombinant inbred lines. RESULTS We identify several tissue-specific master regulatory hotspots that each control the translation rates of multiple proteins. One of these loci is restricted to hypertrophic hearts, where it drives a translatome-wide and protein length-dependent change in translational efficiency, altering the stoichiometric translation rates of sarcomere proteins. Mechanistic dissection of this locus across multiple congenic lines points to a translation machinery defect, characterized by marked differences in polysome profiles and misregulation of the small nucleolar RNA SNORA48. Strikingly, from yeast to humans, we observe reproducible protein length-dependent shifts in translational efficiency as a conserved hallmark of translation machinery mutants, including those that cause ribosomopathies. Depending on the factor mutated, a pre-existing negative correlation between protein length and translation rates could either be enhanced or reduced, which we propose to result from mRNA-specific imbalances in canonical translation initiation and reinitiation rates. CONCLUSIONS We show that distant genetic control of mRNA translation is abundant in mammalian tissues, exemplified by a single genomic locus that triggers a translation-driven molecular mechanism. Our work illustrates the complexity through which genetic variation can drive phenotypic variability between individuals and thereby contribute to complex disease.
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Affiliation(s)
- Franziska Witte
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
- Present Address: NUVISAN ICB GmbH, Lead Discovery-Structrual Biology, 13353, Berlin, Germany
| | - Jorge Ruiz-Orera
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Camilla Ciolli Mattioli
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115, Berlin, Germany
- Present Address: Department of Biological Regulation, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Susanne Blachut
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Eleonora Adami
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
- Present Address: Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore, Singapore, 169857, Singapore
| | - Jana Felicitas Schulz
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Valentin Schneider-Lunitz
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Oliver Hummel
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Giannino Patone
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Michael Benedikt Mücke
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, 13347, Berlin, Germany
- Charité-Universitätsmedizin, 10117, Berlin, Germany
| | - Jan Šilhavý
- Institute of Physiology of the Czech Academy of Sciences, 4, 142 20, Praha, Czech Republic
| | - Matthias Heinig
- Institute of Computational Biology (ICB), HMGU, Ingolstaedter Landstr. 1, 85764 Neuherberg, Munich, Germany
- Department of Informatics, Technische Universitaet Muenchen (TUM), Boltzmannstr. 3, 85748 Garching, Munich, Germany
| | - Leonardo Bottolo
- Department of Medical Genetics, University of Cambridge, Cambridge, CB2 0QQ, UK
- The Alan Turing Institute, London, NW1 2DB, UK
- MRC Biostatistics Unit, University of Cambridge, Cambridge, CB2 0SR, UK
| | - Daniel Sanchis
- Institut de Recerca Biomedica de Lleida (IRBLLEIDA), Universitat de Lleida, Edifici Biomedicina-I. Av. Rovira Roure, 80, 25198, Lleida, Spain
| | - Martin Vingron
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, 14195, Berlin, Germany
| | - Marina Chekulaeva
- Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 10115, Berlin, Germany
| | - Michal Pravenec
- Institute of Physiology of the Czech Academy of Sciences, 4, 142 20, Praha, Czech Republic
| | - Norbert Hubner
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany.
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, 13347, Berlin, Germany.
- Charité-Universitätsmedizin, 10117, Berlin, Germany.
| | - Sebastiaan van Heesch
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany.
- Present Address: The Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands.
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18
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Gaikwad S, Ghobakhlou F, Young DJ, Visweswaraiah J, Zhang H, Hinnebusch AG. Reprogramming of translation in yeast cells impaired for ribosome recycling favors short, efficiently translated mRNAs. eLife 2021; 10:e64283. [PMID: 33764298 PMCID: PMC7993997 DOI: 10.7554/elife.64283] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/04/2021] [Indexed: 12/21/2022] Open
Abstract
In eukaryotes, 43S preinitiation complex (PIC) formation is a rate-determining step of translation. Ribosome recycling following translation termination produces free 40S subunits for re-assembly of 43S PICs. Yeast mutants lacking orthologs of mammalian eIF2D (Tma64), and either MCT-1 (Tma20) or DENR (Tma22), are broadly impaired for 40S recycling; however, it was unknown whether this defect alters the translational efficiencies (TEs) of particular mRNAs. Here, we conducted ribosome profiling of a yeast tma64∆/tma20∆ double mutant and observed a marked reprogramming of translation, wherein the TEs of the most efficiently translated ('strong') mRNAs increase, while those of 'weak' mRNAs generally decline. Remarkably, similar reprogramming was seen on reducing 43S PIC assembly by inducing phosphorylation of eIF2α or by decreasing total 40S subunit levels by depleting Rps26. Our findings suggest that strong mRNAs outcompete weak mRNAs in response to 43S PIC limitation achieved in various ways, in accordance with previous mathematical modeling.
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Affiliation(s)
- Swati Gaikwad
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Fardin Ghobakhlou
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - David J Young
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Jyothsna Visweswaraiah
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Hongen Zhang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Alan G Hinnebusch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
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19
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Akirtava C, McManus CJ. Control of translation by eukaryotic mRNA transcript leaders-Insights from high-throughput assays and computational modeling. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1623. [PMID: 32869519 DOI: 10.1002/wrna.1623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/23/2020] [Accepted: 07/30/2020] [Indexed: 12/21/2022]
Abstract
Eukaryotic gene expression is tightly regulated during translation of mRNA to protein. Mis-regulation of translation can lead to aberrant proteins which accumulate in cancers and cause neurodegenerative diseases. Foundational studies on model genes established fundamental roles for mRNA 5' transcript leader (TL) sequences in controlling ribosome recruitment, scanning, and initiation. TL cis-regulatory elements and their corresponding trans-acting factors control cap-dependent initiation under unstressed conditions. Under stress, cap-dependent initiation is suppressed, and specific mRNA structures and sequences promote translation of stress-responsive transcripts to remodel the proteome. In this review, we summarize current knowledge of TL functions in translation initiation. We focus on insights from high-throughput analyses of ribosome occupancy, mRNA structure, RNA Binding Protein occupancy, and massively parallel reporter assays. These data-driven approaches, coupled with computational analyses and modeling, have paved the way for a comprehensive understanding of TL functions. Finally, we will discuss areas of future research on the roles of mRNA sequences and structures in translation. This article is categorized under: Translation > Translation Mechanisms RNA Evolution and Genomics > Computational Analyses of RNA RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Christina Akirtava
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Charles Joel McManus
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Computational Biology Department, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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20
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Gulay S, Gupta N, Lorsch JR, Hinnebusch AG. Distinct interactions of eIF4A and eIF4E with RNA helicase Ded1 stimulate translation in vivo. eLife 2020; 9:58243. [PMID: 32469309 PMCID: PMC7343385 DOI: 10.7554/elife.58243] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Yeast DEAD-box helicase Ded1 stimulates translation initiation, particularly of mRNAs with structured 5'UTRs. Interactions of the Ded1 N-terminal domain (NTD) with eIF4A, and Ded1-CTD with eIF4G, subunits of eIF4F, enhance Ded1 unwinding activity and stimulation of preinitiation complex (PIC) assembly in vitro. However, the importance of these interactions, and of Ded1-eIF4E association, in vivo were poorly understood. We identified separate amino acid clusters in the Ded1-NTD required for binding to eIF4A or eIF4E in vitro. Disrupting each cluster selectively impairs native Ded1 association with eIF4A or eIF4E, and reduces cell growth, polysome assembly, and translation of reporter mRNAs with structured 5'UTRs. It also impairs Ded1 stimulation of PIC assembly on a structured mRNA in vitro. Ablating Ded1 interactions with eIF4A/eIF4E unveiled a requirement for the Ded1-CTD for robust initiation. Thus, Ded1 function in vivo is stimulated by independent interactions of its NTD with eIF4E and eIF4A, and its CTD with eIF4G.
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Affiliation(s)
- Suna Gulay
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Neha Gupta
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Jon R Lorsch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - 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, United States
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21
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Zhou F, Zhang H, Kulkarni SD, Lorsch JR, Hinnebusch AG. eIF1 discriminates against suboptimal initiation sites to prevent excessive uORF translation genome-wide. RNA (NEW YORK, N.Y.) 2020; 26:419-438. [PMID: 31915290 PMCID: PMC7075259 DOI: 10.1261/rna.073536.119] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/06/2020] [Indexed: 05/22/2023]
Abstract
The translation preinitiation complex (PIC) scans the mRNA for an AUG codon in a favorable context. Previous findings suggest that the factor eIF1 discriminates against non-AUG start codons by impeding full accommodation of Met-tRNAi in the P site of the 40S ribosomal subunit, necessitating eIF1 dissociation for start codon selection. Consistent with this, yeast eIF1 substitutions that weaken its binding to the PIC increase initiation at UUG codons on a mutant his4 mRNA and particular synthetic mRNA reporters; and also at the AUG start codon of the mRNA for eIF1 itself owing to its poor Kozak context. It was not known however whether such eIF1 mutants increase initiation at suboptimal start codons genome-wide. By ribosome profiling, we show that the eIF1-L96P variant confers increased translation of numerous upstream open reading frames (uORFs) initiating with either near-cognate codons (NCCs) or AUGs in poor context. The increased uORF translation is frequently associated with the reduced translation of the downstream main coding sequences (CDS). Initiation is also elevated at certain NCCs initiating amino-terminal extensions, including those that direct mitochondrial localization of the GRS1 and ALA1 products, and at a small set of main CDS AUG codons with especially poor context, including that of eIF1 itself. Thus, eIF1 acts throughout the yeast translatome to discriminate against NCC start codons and AUGs in poor context; and impairing this function enhances the repressive effects of uORFs on CDS translation and alters the ratios of protein isoforms translated from near-cognate versus AUG start codons.
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Affiliation(s)
- Fujun Zhou
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Hongen Zhang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Shardul D Kulkarni
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jon R Lorsch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Alan G Hinnebusch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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22
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Waldron JA, Tack DC, Ritchey LE, Gillen SL, Wilczynska A, Turro E, Bevilacqua PC, Assmann SM, Bushell M, Le Quesne J. mRNA structural elements immediately upstream of the start codon dictate dependence upon eIF4A helicase activity. Genome Biol 2019; 20:300. [PMID: 31888698 PMCID: PMC6936103 DOI: 10.1186/s13059-019-1901-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/26/2019] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The RNA helicase eIF4A1 is a key component of the translation initiation machinery and is required for the translation of many pro-oncogenic mRNAs. There is increasing interest in targeting eIF4A1 therapeutically in cancer, thus understanding how this protein leads to the selective re-programming of the translational landscape is critical. While it is known that eIF4A1-dependent mRNAs frequently have long GC-rich 5'UTRs, the details of how 5'UTR structure is resculptured by eIF4A1 to enhance the translation of specific mRNAs are unknown. RESULTS Using Structure-seq2 and polysome profiling, we assess global mRNA structure and translational efficiency in MCF7 cells, with and without eIF4A inhibition with hippuristanol. We find that eIF4A inhibition does not lead to global increases in 5'UTR structure, but rather it leads to 5'UTR remodeling, with localized gains and losses of structure. The degree of these localized structural changes is associated with 5'UTR length, meaning that eIF4A-dependent mRNAs have greater localized gains of structure due to their increased 5'UTR length. However, it is not solely increased localized structure that causes eIF4A-dependency but the position of the structured regions, as these structured elements are located predominantly at the 3' end of the 5'UTR. CONCLUSIONS By measuring changes in RNA structure following eIF4A inhibition, we show that eIF4A remodels local 5'UTR structures. The location of these structural elements ultimately determines the dependency on eIF4A, with increased structure just upstream of the CDS being the major limiting factor in translation, which is overcome by eIF4A activity.
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Affiliation(s)
- Joseph A Waldron
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
| | - David C Tack
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
- Present Address: Spectrum Health Office of Research, 100 Michigan Street NE, Mail Code 038, Grand Rapids, MI, 49503, USA
| | - Laura E Ritchey
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
- Present Address: Department of Chemistry, University of Pittsburgh at Johnstown, Johnstown, PA, 15904, USA
| | - Sarah L Gillen
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Ania Wilczynska
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Ernest Turro
- Department of Haematology, University of Cambridge, Cambridge, UK
- Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge, UK
- National Health Service Blood and Transplant, Cambridge, UK
- National Institute for Health Research BioResource, Cambridge University Hospitals, Cambridge, UK
| | - Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
- Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow, G61 1QH, UK.
| | - John Le Quesne
- Medical Research Council Toxicology Unit, University of Cambridge, Hodgkin Building, Lancaster Road, Leicester, LE1 7HB, UK.
- Leicester Cancer Research Centre, University of Leicester, Leicester, UK.
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23
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Mishra RK, Datey A, Hussain T. mRNA Recruiting eIF4 Factors Involved in Protein Synthesis and Its Regulation. Biochemistry 2019; 59:34-46. [DOI: 10.1021/acs.biochem.9b00788] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Rishi Kumar Mishra
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
| | - Ayushi Datey
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
| | - Tanweer Hussain
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
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