1
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Chen R, Stainier W, Dufourt J, Lagha M, Lehmann R. Direct observation of translational activation by a ribonucleoprotein granule. Nat Cell Biol 2024:10.1038/s41556-024-01452-5. [PMID: 38965420 DOI: 10.1038/s41556-024-01452-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 05/30/2024] [Indexed: 07/06/2024]
Abstract
Biomolecular condensates organize biochemical processes at the subcellular level and can provide spatiotemporal regulation within a cell. Among these, ribonucleoprotein (RNP) granules are storage hubs for translationally repressed mRNA. Whether RNP granules can also activate translation and how this could be achieved remains unclear. Here, using single-molecule imaging, we demonstrate that the germ cell-determining RNP granules in Drosophila embryos are sites for active translation of nanos mRNA. Nanos translation occurs preferentially at the germ granule surface with the 3' UTR buried within the granule. Smaug, a cytosolic RNA-binding protein, represses nanos translation, which is relieved when Smaug is sequestered to the germ granule by the scaffold protein Oskar. Together, our findings uncover a molecular process by which RNP granules achieve localized protein synthesis through the compartmentalized loss of translational repression.
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Affiliation(s)
- Ruoyu Chen
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Vilcek Institute of Graduate Studies, NYU School of Medicine, New York, NY, USA
| | - William Stainier
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Immunobiology Laboratory, The Francis Crick Institute, London, UK
| | - Jeremy Dufourt
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, Montpellier, France
- Institut de Recherche en Infectiologie de Montpellier, University of Montpellier, Montpellier, France
| | - Mounia Lagha
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, Montpellier, France
| | - Ruth Lehmann
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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2
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Morisaki T, Wiggan O, Stasevich TJ. Translation Dynamics of Single mRNAs in Live Cells. Annu Rev Biophys 2024; 53:65-85. [PMID: 38134333 DOI: 10.1146/annurev-biophys-030822-034116] [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: 12/24/2023]
Abstract
The translation of messenger RNA (mRNA) into proteins represents the culmination of gene expression. Recent technological advances have revolutionized our ability to investigate this process with unprecedented precision, enabling the study of translation at the single-molecule level in real time within live cells. In this review, we provide an overview of single-mRNA translation reporters. We focus on the core technology, as well as the rapid development of complementary probes, tags, and accessories that enable the visualization and quantification of a wide array of translation dynamics. We then highlight notable studies that have utilized these reporters in model systems to address key biological questions. The high spatiotemporal resolution of these studies is shedding light on previously unseen phenomena, uncovering the full heterogeneity and complexity of translational regulation.
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Affiliation(s)
- Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA;
| | - O'Neil Wiggan
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA;
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA;
- Cell Biology Center and World Research Hub Initiative, Tokyo Institute of Technology, Yokohama, Japan
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3
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McShane E, Churchman LS. Central dogma rates in human mitochondria. Hum Mol Genet 2024; 33:R34-R41. [PMID: 38779776 PMCID: PMC11112385 DOI: 10.1093/hmg/ddae036] [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: 12/28/2023] [Revised: 12/28/2023] [Accepted: 02/29/2024] [Indexed: 05/25/2024] Open
Abstract
In human cells, the nuclear and mitochondrial genomes engage in a complex interplay to produce dual-encoded oxidative phosphorylation (OXPHOS) complexes. The coordination of these dynamic gene expression processes is essential for producing matched amounts of OXPHOS protein subunits. This review focuses on our current understanding of the mitochondrial central dogma rates, highlighting the striking differences in gene expression rates between mitochondrial and nuclear genes. We synthesize a coherent model of mitochondrial gene expression kinetics, highlighting the emerging principles and emphasizing where more precise measurements would be beneficial. Such an understanding is pivotal for grasping the unique aspects of mitochondrial function and its role in cellular energetics, and it has profound implications for aging, metabolic disorders, and neurodegenerative diseases.
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Affiliation(s)
- Erik McShane
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, United States
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, United States
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4
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McShane E, Couvillion M, Ietswaart R, Prakash G, Smalec BM, Soto I, Baxter-Koenigs AR, Choquet K, Churchman LS. A kinetic dichotomy between mitochondrial and nuclear gene expression processes. Mol Cell 2024; 84:1541-1555.e11. [PMID: 38503286 PMCID: PMC11236289 DOI: 10.1016/j.molcel.2024.02.028] [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: 09/05/2023] [Revised: 12/12/2023] [Accepted: 02/27/2024] [Indexed: 03/21/2024]
Abstract
Oxidative phosphorylation (OXPHOS) complexes, encoded by both mitochondrial and nuclear DNA, are essential producers of cellular ATP, but how nuclear and mitochondrial gene expression steps are coordinated to achieve balanced OXPHOS subunit biogenesis remains unresolved. Here, we present a parallel quantitative analysis of the human nuclear and mitochondrial messenger RNA (mt-mRNA) life cycles, including transcript production, processing, ribosome association, and degradation. The kinetic rates of nearly every stage of gene expression differed starkly across compartments. Compared with nuclear mRNAs, mt-mRNAs were produced 1,100-fold more, degraded 7-fold faster, and accumulated to 160-fold higher levels. Quantitative modeling and depletion of mitochondrial factors LRPPRC and FASTKD5 identified critical points of mitochondrial regulatory control, revealing that the mitonuclear expression disparities intrinsically arise from the highly polycistronic nature of human mitochondrial pre-mRNA. We propose that resolving these differences requires a 100-fold slower mitochondrial translation rate, illuminating the mitoribosome as a nexus of mitonuclear co-regulation.
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Affiliation(s)
- Erik McShane
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Mary Couvillion
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Robert Ietswaart
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Gyan Prakash
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Brendan M Smalec
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Iliana Soto
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Autum R Baxter-Koenigs
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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5
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Haase N, Holtkamp W, Christ S, Heinemann D, Rodnina MV, Rudorf S. Decomposing bulk signals to reveal hidden information in processive enzyme reactions: A case study in mRNA translation. PLoS Comput Biol 2024; 20:e1011918. [PMID: 38442108 PMCID: PMC10942256 DOI: 10.1371/journal.pcbi.1011918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 03/15/2024] [Accepted: 02/14/2024] [Indexed: 03/07/2024] Open
Abstract
Processive enzymes like polymerases or ribosomes are often studied in bulk experiments by monitoring time-dependent signals, such as fluorescence time traces. However, due to biomolecular process stochasticity, ensemble signals may lack the distinct features of single-molecule signals. Here, we demonstrate that, under certain conditions, bulk signals from processive reactions can be decomposed to unveil hidden information about individual reaction steps. Using mRNA translation as a case study, we show that decomposing a noisy ensemble signal generated by the translation of mRNAs with more than a few codons is an ill-posed problem, addressable through Tikhonov regularization. We apply our method to the fluorescence signatures of in-vitro translated LepB mRNA and determine codon-position dependent translation rates and corresponding state-specific fluorescence intensities. We find a significant change in fluorescence intensity after the fourth and the fifth peptide bond formation, and show that both codon position and encoded amino acid have an effect on the elongation rate. This demonstrates that our approach enhances the information content extracted from bulk experiments, thereby expanding the range of these time- and cost-efficient methods.
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Affiliation(s)
- Nadin Haase
- Leibniz University Hannover, Institute of Cell Biology and Biophysics, Hannover, Germany
| | - Wolf Holtkamp
- Max Planck Institute for Multidisciplinary Sciences, Department of Physical Biochemistry, Göttingen, Germany
- Paul-Ehrlich-Institut, Division of Allergology, Langen, Germany
| | - Simon Christ
- Leibniz University Hannover, Institute of Cell Biology and Biophysics, Hannover, Germany
| | - Dag Heinemann
- Leibniz University Hannover, Hannover Centre for Optical Technologies (HOT), Hannover, Germany
- Leibniz University Hannover, Institute of Horticultural Production Systems, Hannover, Germany
- Leibniz University Hannover, PhoenixD Cluster of Excellence, Hannover, Germany
| | - Marina V. Rodnina
- Max Planck Institute for Multidisciplinary Sciences, Department of Physical Biochemistry, Göttingen, Germany
| | - Sophia Rudorf
- Leibniz University Hannover, Institute of Cell Biology and Biophysics, Hannover, Germany
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6
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Blake LA, De La Cruz A, Wu B. Imaging spatiotemporal translation regulation in vivo. Semin Cell Dev Biol 2024; 154:155-164. [PMID: 36963991 PMCID: PMC10514244 DOI: 10.1016/j.semcdb.2023.03.006] [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: 03/23/2022] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023]
Abstract
Translation is regulated spatiotemporally to direct protein synthesis when and where it is needed. RNA localization and local translation have been observed in various subcellular compartments, allowing cells to rapidly and finely adjust their proteome post-transcriptionally. Local translation on membrane-bound organelles is important to efficiently synthesize proteins targeted to the organelles. Protein-RNA phase condensates restrict RNA spatially in membraneless organelles and play essential roles in translation regulation and RNA metabolism. In addition, the temporal translation kinetics not only determine the amount of protein produced, but also serve as an important checkpoint for the quality of ribosomes, mRNAs, and nascent proteins. Translation imaging provides a unique capability to study these fundamental processes in the native environment. Recent breakthroughs in imaging enabled real-time visualization of translation of single mRNAs, making it possible to determine the spatial distribution and key biochemical parameters of in vivo translation dynamics. Here we reviewed the recent advances in translation imaging methods and their applications to study spatiotemporal translation regulation in vivo.
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Affiliation(s)
- Lauren A Blake
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ana De La Cruz
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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7
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Zhang D, Gao Y, Zhu L, Wang Y, Li P. Advances and opportunities in methods to study protein translation - A review. Int J Biol Macromol 2024; 259:129150. [PMID: 38171441 DOI: 10.1016/j.ijbiomac.2023.129150] [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: 08/02/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/05/2024]
Abstract
It is generally believed that the regulation of gene expression involves protein translation occurring before RNA transcription. Therefore, it is crucial to investigate protein translation and its regulation. Recent advancements in biological sciences, particularly in the field of omics, have revolutionized protein translation research. These studies not only help characterize changes in protein translation during specific biological or pathological processes but also have significant implications in disease prevention and treatment. In this review, we summarize the latest methods in ribosome-based translation omics. We specifically focus on the application of fluorescence imaging technology and omics technology in studying overall protein translation. Additionally, we analyze the advantages, disadvantages, and application of these experimental methods, aiming to provide valuable insights and references to researchers studying translation.
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Affiliation(s)
- Dejiu Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Yanyan Gao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Lei Zhu
- College of Basic Medical, Qingdao Binhai University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
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8
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Li Y, Xu M, Qi Z. Deciphering molecular mechanisms of phase separation in RNA biology by single-molecule biophysical technologies. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1034-1041. [PMID: 37337634 PMCID: PMC10415185 DOI: 10.3724/abbs.2023113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/06/2023] [Indexed: 06/21/2023] Open
Abstract
Ribonucleic acid (RNA) biology has emerged as one of the most important areas in modern biology and biomedicine. RNA and RNA-binding proteins (RBPs) are involved in forming biomolecular condensates, which are crucial for RNA metabolism. To quantitively decipher the molecular mechanisms of RNP granules, researchers have turned to single-molecule biophysical techniques, such as single-molecule Förster resonance energy transfer (smFRET), in vivo single-molecule imaging technique with single particle tracking (SPT), DNA Curtains, optical tweezers, and atomic force microscopy (AFM). These methods are used to investigate the molecular biophysical properties within RNP granules, as well as the molecular interactions between RNA and RBPs and RBPs themselves, which are challenging to study using traditional experimental methods of the liquid-liquid phase separation (LLPS) field, such as fluorescence recovery after photobleaching (FRAP). In this work, we summarize the applications of single-molecule biophysical techniques in RNP granule studies and highlight how these methods can be used to reveal the molecular mechanisms of RNP granules.
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Affiliation(s)
- Yuchen Li
- Center for Quantitative Biology and Peking-Tsinghua Center for Life SciencesAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijing100871China
| | - Mengmeng Xu
- Tsinghua-Peking Center for Life SciencesTsinghua UniversityBeijing100084China
| | - Zhi Qi
- Center for Quantitative Biology and Peking-Tsinghua Center for Life SciencesAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijing100871China
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9
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Chen W, Zhao X, Yang N, Li X. Single mRNA Imaging with Fluorogenic RNA Aptamers and Small-molecule Fluorophores. Angew Chem Int Ed Engl 2023; 62:e202209813. [PMID: 36420710 DOI: 10.1002/anie.202209813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/07/2022] [Accepted: 11/24/2022] [Indexed: 11/25/2022]
Abstract
Messenger RNA (mRNA) is the fundamental information transfer system in the cell. Tracking single mRNA from transcription to degradation with fluorescent probes provides spatiotemporal information in cells about how the genetic information is transferred from DNA to proteins. The traditional single mRNA imaging approach utilizes RNA hairpins (e.g. MS2) and tethered fluorescent protein as probes. As an exciting alternative, RNA aptamers: small-molecule fluorophores (SFs) systems have emerged as novel single mRNA imaging probes since 2019, exhibiting several advantages including fluorogenic ability and minimal perturbation. This review summarizes all five reported RNA aptamers: SFs systems for single mRNA imaging in living cells so far. It also discusses the challenges and provides prospects for single mRNA imaging applications. This review is expected to inspire researchers to develop RNA aptamers: SFs systems for studying gene expression at single-molecule resolution in cells.
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Affiliation(s)
- Wei Chen
- Institute of Cytology and Genetics, the Hengyang Key Laboratory of Cellular Stress Biology, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China.,Beijing Institutes of Life Science, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Science, Beijing, 100101, China
| | - Xiaoying Zhao
- College of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Nanyang Yang
- Institute of Cytology and Genetics, the Hengyang Key Laboratory of Cellular Stress Biology, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Xing Li
- Beijing Institutes of Life Science, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Science, Beijing, 100101, China
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10
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Gandin V, English BP, Freeman M, Leroux LP, Preibisch S, Walpita D, Jaramillo M, Singer RH. Cap-dependent translation initiation monitored in living cells. Nat Commun 2022; 13:6558. [PMID: 36323665 PMCID: PMC9630388 DOI: 10.1038/s41467-022-34052-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 10/06/2022] [Indexed: 11/19/2022] Open
Abstract
mRNA translation is tightly regulated to preserve cellular homeostasis. Despite extensive biochemical, genetic, and structural studies, a detailed understanding of mRNA translation regulation is lacking. Imaging methodologies able to resolve the binding dynamics of translation factors at single-cell and single-mRNA resolution were necessary to fully elucidate regulation of this paramount process. Here live-cell spectroscopy and single-particle tracking were combined to interrogate the binding dynamics of endogenous initiation factors to the 5'cap. The diffusion of initiation factors (IFs) changed markedly upon their association with mRNA. Quantifying their diffusion characteristics revealed the sequence of IFs assembly and disassembly in cell lines and the clustering of translation in neurons. This approach revealed translation regulation at high spatial and temporal resolution that can be applied to the formation of any endogenous complex that results in a measurable shift in diffusion.
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Affiliation(s)
- Valentina Gandin
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Brian P. English
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Melanie Freeman
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Louis-Philippe Leroux
- grid.418084.10000 0000 9582 2314Institut National de la Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie (CAFSB), Laval, QC Canada
| | - Stephan Preibisch
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Deepika Walpita
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
| | - Maritza Jaramillo
- grid.418084.10000 0000 9582 2314Institut National de la Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie (CAFSB), Laval, QC Canada
| | - Robert H. Singer
- grid.443970.dJanelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA USA
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11
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Skelton R, Roach A, Prudhomme LE, Cen Feng JYC, Gaikwad P, Williams RM. Formulation of Lipid-Free Polymeric Mesoscale Nanoparticles Encapsulating mRNA. Pharm Res 2022; 39:2699-2707. [PMID: 36163410 PMCID: PMC9513001 DOI: 10.1007/s11095-022-03398-5] [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: 05/15/2022] [Accepted: 09/14/2022] [Indexed: 11/27/2022]
Abstract
Introduction Nanoparticle-mediated gene therapy has found substantial clinical impact, primarily focused on lipid-based nanoparticles. In comparison with lipid nanoparticles, polymeric particles may have certain advantages such as increased biocompatibility and controlled release. Our prior studies have found that polymeric mesoscale nanoparticles exhibited specific targeting to the renal proximal tubules. Thus, in this study, we sought to identify formulation parameters that allow for development of polymeric mesoscale nanoparticles encapsulating functional mRNA for delivery into tubular epithelial cells. Methods We evaluated particle uptake in vitro prior to exploring formulation parameters related to introduction of a primary mixture of polymer in acetonitrile and hydrophilic mRNA in water. Finally, we evaluated their functionality in a renal tubular epithelial cell line. Results We found that MNPs are endocytosed within 15 min and that the mesoscale nanoparticle formulation procedure was generally robust to introduction of a primary mixture and encapsulation of mRNA. These particles exhibited substantial uptake in renal cells in vitro and rapid (< 1 h) expression of a model mCherry fluorescent protein. Conclusion We anticipate these findings having potential in the delivery of specific gene therapies for renal disorders and cancer.
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Affiliation(s)
- Rachel Skelton
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA
| | - Arantxa Roach
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA
| | - Lauren E Prudhomme
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA
| | | | - Pooja Gaikwad
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA
- PhD Program in Chemistry, Graduate Center, City University of New York, New York, NY, 10016, USA
| | - Ryan M Williams
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA.
- PhD Program in Chemistry, Graduate Center, City University of New York, New York, NY, 10016, USA.
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12
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Cialek CA, Galindo G, Morisaki T, Zhao N, Montgomery TA, Stasevich TJ. Imaging translational control by Argonaute with single-molecule resolution in live cells. Nat Commun 2022; 13:3345. [PMID: 35688806 PMCID: PMC9187665 DOI: 10.1038/s41467-022-30976-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 05/24/2022] [Indexed: 11/29/2022] Open
Abstract
A major challenge to our understanding of translational control has been deconvolving the individual impact specific regulatory factors have on the complex dynamics of mRNA translation. MicroRNAs (miRNAs), for example, guide Argonaute and associated proteins to target mRNAs, where they direct gene silencing in multiple ways that are not well understood. To better deconvolve these dynamics, we have developed technology to directly visualize and quantify the impact of human Argonaute2 (Ago2) on the translation and subcellular localization of individual reporter mRNAs in living cells. We show that our combined translation and Ago2 tethering sensor reflects endogenous miRNA-mediated gene silencing. Using the sensor, we find that Ago2 association leads to progressive silencing of translation at individual mRNA. Silencing was occasionally interrupted by brief bursts of translational activity and took 3–4 times longer than a single round of translation, consistent with a gradual increase in the inhibition of translation initiation. At later time points, Ago2-tethered mRNAs cluster and coalesce with P-bodies, where a translationally silent state is maintained. These results provide a framework for exploring miRNA-mediated gene regulation in live cells at the single-molecule level. Furthermore, our tethering-based, single-molecule reporter system will likely have wide-ranging application in studying RNA-protein interactions. Guided by miRNA, Argonaute proteins silence mRNA in multiple ways that are not well understood. Here, the authors develop live-cell biosensors to image the impact tethered regulatory factors, such as Argonaute, have on single-mRNA translation dynamics.
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Affiliation(s)
- Charlotte A Cialek
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gabriel Galindo
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Tatsuya Morisaki
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Ning Zhao
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Taiowa A Montgomery
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Timothy J Stasevich
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA. .,Cell Biology Center and World Research Hub Initiative, Tokyo Institute of Technology, Yokohama, Japan.
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13
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Gasparski AN, Mason DE, Moissoglu K, Mili S. Regulation and outcomes of localized RNA translation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1721. [PMID: 35166036 PMCID: PMC9787767 DOI: 10.1002/wrna.1721] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/18/2022] [Accepted: 01/22/2022] [Indexed: 12/31/2022]
Abstract
Spatial segregation of mRNAs in the cytoplasm of cells is a well-known biological phenomenon that is widely observed in diverse species spanning different kingdoms of life. In mammalian cells, localization of mRNAs has been documented and studied quite extensively in highly polarized cells, most notably in neurons, where localized mRNAs function to direct protein production at sites that are quite distant from the soma. Recent studies have strikingly revealed that a large proportion of the cellular transcriptome exhibits polarized distributions even in cells that lack an obvious need for long-range transport, such as fibroblasts or epithelial cells. This review focuses on emerging concepts regarding the functional outcomes of mRNA targeting in the cytoplasm of such cells. We also discuss regulatory mechanisms controlling these events, with an emphasis on the role of cell mechanics and the organization of the cytoskeleton. This article is categorized under: Translation > Regulation RNA Export and Localization > RNA Localization.
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Affiliation(s)
- Alexander N. Gasparski
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
| | - Devon E. Mason
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
| | - Konstadinos Moissoglu
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
| | - Stavroula Mili
- Laboratory of Cellular and Molecular Biology, Center for Cancer ResearchNational Cancer Institute, NIHBethesdaMarylandUSA
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14
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Morisaki T, Stasevich TJ. Single-Molecule Imaging of mRNA Interactions with Stress Granules. Methods Mol Biol 2022; 2428:349-360. [PMID: 35171490 PMCID: PMC9191879 DOI: 10.1007/978-1-0716-1975-9_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Single-molecule imaging in living cells enables the investigation of molecular dynamics and interactions underlying the physiology of a cell. We recently developed a method to visualize translation events at single-mRNA resolution in living cells. Here we describe how we apply this method to visualize mRNA interactions with stress granules in the context of translational activity during cell stress.
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Affiliation(s)
- Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Timothy J Stasevich
- World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
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15
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Vinter DJ, Hoppe C, Ashe HL. Live and fixed imaging of translation sites at single mRNA resolution in the Drosophila embryo. STAR Protoc 2021; 2:100812. [PMID: 34585149 PMCID: PMC8450298 DOI: 10.1016/j.xpro.2021.100812] [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] [Indexed: 11/26/2022] Open
Abstract
Significant regulation of gene expression is mediated at the translation level. Here, we describe protocols for imaging and analysis of translation at single mRNA resolution in both fixed and living Drosophila embryos. These protocols use the SunTag system, in which the protein of interest is visualized by inserting a peptide array that is recognized by a single chain antibody. Simultaneous detection of individual mRNAs using the MS2/MCP system or by smFISH allows translation sites to be identified and quantified. For complete information on the generation and use of this protocol, please refer to Vinter et al. (2021).
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Affiliation(s)
- Daisy J. Vinter
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Caroline Hoppe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Hilary L. Ashe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
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16
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Vinter DJ, Hoppe C, Minchington TG, Sutcliffe C, Ashe HL. Dynamics of hunchback translation in real-time and at single-mRNA resolution in the Drosophila embryo. Development 2021; 148:dev196121. [PMID: 33722899 PMCID: PMC8077512 DOI: 10.1242/dev.196121] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 03/10/2021] [Indexed: 12/15/2022]
Abstract
The Hunchback (Hb) transcription factor is crucial for anterior-posterior patterning of the Drosophila embryo. The maternal hb mRNA acts as a paradigm for translational regulation due to its repression in the posterior of the embryo. However, little is known about the translatability of zygotically transcribed hb mRNAs. Here, we adapt the SunTag system, developed for imaging translation at single-mRNA resolution in tissue culture cells, to the Drosophila embryo to study the translation dynamics of zygotic hb mRNAs. Using single-molecule imaging in fixed and live embryos, we provide evidence for translational repression of zygotic SunTag-hb mRNAs. Whereas the proportion of SunTag-hb mRNAs translated is initially uniform, translation declines from the anterior over time until it becomes restricted to a posterior band in the expression domain. We discuss how regulated hb mRNA translation may help establish the sharp Hb expression boundary, which is a model for precision and noise during developmental patterning. Overall, our data show how use of the SunTag method on fixed and live embryos is a powerful combination for elucidating spatiotemporal regulation of mRNA translation in Drosophila.
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Affiliation(s)
| | | | | | | | - Hilary L. Ashe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
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17
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Koch AL, Morisaki T, Stasevich TJ. A Multi-color Bicistronic Biosensor to Compare the Translation Dynamics of Different Open Reading Frames at Single-molecule Resolution in Live Cells. Bio Protoc 2021; 11:e4096. [PMID: 34395732 DOI: 10.21769/bioprotoc.4096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/29/2021] [Accepted: 05/16/2021] [Indexed: 11/02/2022] Open
Abstract
Here, we describe how to image and quantitate the translation dynamics of a bicistronic biosensor that we recently created to fairly compare cap-dependent and IRES-mediated translation at single-molecule resolution in live human cells. This technique employs a pair of complementary intrabodies loaded into living cells that co-translationally bind complementary epitopes in the two separate ORFs of the bicistronic biosensor. This causes the biosensor to fluoresce in different colors depending on which ORF/epitopes are translated. Using the biosensor together with high-resolution fluorescence microscopy and single-molecule tracking analysis allows for the quantitative comparison of translation dynamics between the two ORFs at a resolution of tens-of-nanometers in space and sub-seconds in time, which is not possible with more traditional GFP or luciferase reporters. Since both ORFs are on the same biosensor, they experience the same microenvironment, allowing a fair comparison of their relative translational activities. In this protocol, we describe how to get this assay up and running in cultured human cells so that translation dynamics can be studied under both normal and stressful cellular conditions. We also provide a number of useful tips and notes to help express components at appropriate levels inside cells for optimal live cell imaging. Graphical abstract: Steps required for 3-color single-molecule translation imaging and analysis.
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Affiliation(s)
- Amanda L Koch
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.,Cell Biology Center and World Research Hub Initiative, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan
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18
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Rodrigues DC, Mufteev M, Weatheritt RJ, Djuric U, Ha KCH, Ross PJ, Wei W, Piekna A, Sartori MA, Byres L, Mok RSF, Zaslavsky K, Pasceri P, Diamandis P, Morris Q, Blencowe BJ, Ellis J. Shifts in Ribosome Engagement Impact Key Gene Sets in Neurodevelopment and Ubiquitination in Rett Syndrome. Cell Rep 2021; 30:4179-4196.e11. [PMID: 32209477 DOI: 10.1016/j.celrep.2020.02.107] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 12/30/2019] [Accepted: 02/27/2020] [Indexed: 12/21/2022] Open
Abstract
Regulation of translation during human development is poorly understood, and its dysregulation is associated with Rett syndrome (RTT). To discover shifts in mRNA ribosomal engagement (RE) during human neurodevelopment, we use parallel translating ribosome affinity purification sequencing (TRAP-seq) and RNA sequencing (RNA-seq) on control and RTT human induced pluripotent stem cells, neural progenitor cells, and cortical neurons. We find that 30% of transcribed genes are translationally regulated, including key gene sets (neurodevelopment, transcription and translation factors, and glycolysis). Approximately 35% of abundant intergenic long noncoding RNAs (lncRNAs) are ribosome engaged. Neurons translate mRNAs more efficiently and have longer 3' UTRs, and RE correlates with elements for RNA-binding proteins. RTT neurons have reduced global translation and compromised mTOR signaling, and >2,100 genes are translationally dysregulated. NEDD4L E3-ubiquitin ligase is translationally impaired, ubiquitinated protein levels are reduced, and protein targets accumulate in RTT neurons. Overall, the dynamic translatome in neurodevelopment is disturbed in RTT and provides insight into altered ubiquitination that may have therapeutic implications.
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Affiliation(s)
- Deivid C Rodrigues
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Marat Mufteev
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Robert J Weatheritt
- Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Ugljesa Djuric
- Laboratory Medicine and Pathology Program, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Kevin C H Ha
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Vector Institute, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - P Joel Ross
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Wei Wei
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Alina Piekna
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Maria A Sartori
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Loryn Byres
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Rebecca S F Mok
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Kirill Zaslavsky
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Peter Pasceri
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Phedias Diamandis
- Laboratory Medicine and Pathology Program, University Health Network, Toronto, ON M5G 2C4, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A1, Canada; Department of Pathology, University Health Network, Toronto, ON M5G 2C4, Canada
| | - Quaid Morris
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Vector Institute, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Benjamin J Blencowe
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - James Ellis
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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19
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Gaba A, Wang H, Fortune T, Qu X. Smart-ORF: a single-molecule method for accessing ribosome dynamics in both upstream and main open reading frames. Nucleic Acids Res 2021; 49:e26. [PMID: 33330921 PMCID: PMC7969011 DOI: 10.1093/nar/gkaa1185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 11/15/2022] Open
Abstract
Upstream open reading frame (uORF) translation disrupts scanning 43S flux on mRNA and modulates main open reading frame (mORF) translation efficiency. Current tools, however, have limited access to ribosome dynamics in both upstream and main ORFs of an mRNA. Here, we develop a new two-color in vitro fluorescence assay, Smart-ORF, that monitors individual uORF and mORF translation events in real-time with single-molecule resolution. We demonstrate the utility of Smart-ORF by applying it to uORF-encoded arginine attenuator peptide (AAP)-mediated translational regulation. The method enabled quantification of uORF and mORF initiation efficiencies, 80S dwell time, polysome formation, and the correlation between uORF and mORF translation dynamics. Smart-ORF revealed that AAP-mediated 80S stalling in the uORF stimulates the uORF initiation efficiency and promotes clustering of slower uORF-translating ribosomes. This technology provides a new tool that can reveal previously uncharacterized dynamics of uORF-containing mRNA translation.
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Affiliation(s)
- Anthony Gaba
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Hongyun Wang
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Trinisia Fortune
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Xiaohui Qu
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
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20
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Neelagandan N, Lamberti I, Carvalho HJF, Gobet C, Naef F. What determines eukaryotic translation elongation: recent molecular and quantitative analyses of protein synthesis. Open Biol 2020; 10:200292. [PMID: 33292102 PMCID: PMC7776565 DOI: 10.1098/rsob.200292] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/10/2020] [Indexed: 12/14/2022] Open
Abstract
Protein synthesis from mRNA is an energy-intensive and tightly controlled cellular process. Translation elongation is a well-coordinated, multifactorial step in translation that undergoes dynamic regulation owing to cellular state and environmental determinants. Recent studies involving genome-wide approaches have uncovered some crucial aspects of translation elongation including the mRNA itself and the nascent polypeptide chain. Additionally, these studies have fuelled quantitative and mathematical modelling of translation elongation. In this review, we provide a comprehensive overview of the key determinants of translation elongation. We discuss consequences of ribosome stalling or collision, and how the cells regulate translation in case of such events. Next, we review theoretical approaches and widely used mathematical models that have become an essential ingredient to interpret complex molecular datasets and study translation dynamics quantitatively. Finally, we review recent advances in live-cell reporter and related analysis techniques, to monitor the translation dynamics of single cells and single-mRNA molecules in real time.
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Affiliation(s)
| | | | | | | | - Felix Naef
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
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21
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Koch A, Aguilera L, Morisaki T, Munsky B, Stasevich TJ. Quantifying the dynamics of IRES and cap translation with single-molecule resolution in live cells. Nat Struct Mol Biol 2020; 27:1095-1104. [PMID: 32958947 DOI: 10.1038/s41594-020-0504-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/12/2020] [Indexed: 12/12/2022]
Abstract
Viruses use internal ribosome entry sites (IRES) to hijack host ribosomes and promote cap-independent translation. Although they are well-studied in bulk, the dynamics of IRES-mediated translation remain unexplored at the single-molecule level. Here, we developed a bicistronic biosensor encoding distinct repeat epitopes in two open reading frames (ORFs), one translated from the 5' cap, and the other from the encephalomyocarditis virus IRES. When combined with a pair of complementary probes that bind the epitopes cotranslationally, the biosensor lights up in different colors depending on which ORF is translated. Using the sensor together with single-molecule tracking and computational modeling, we measured the kinetics of cap-dependent versus IRES-mediated translation in living human cells. We show that bursts of IRES translation are shorter and rarer than bursts of cap translation, although the situation reverses upon stress. Collectively, our data support a model for translational regulation primarily driven by transitions between translationally active and inactive RNA states.
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Affiliation(s)
- Amanda Koch
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Luis Aguilera
- Keck Scholars, Department of Chemical and Biological Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Brian Munsky
- Keck Scholars, Department of Chemical and Biological Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA.
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA. .,World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan.
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22
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Cialek CA, Koch AL, Galindo G, Stasevich TJ. Lighting up single-mRNA translation dynamics in living cells. Curr Opin Genet Dev 2020; 61:75-82. [PMID: 32408104 PMCID: PMC7508770 DOI: 10.1016/j.gde.2020.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/12/2020] [Accepted: 04/08/2020] [Indexed: 12/11/2022]
Abstract
Over the past five years, technological advances have made it possible to image the translation of single mRNA in the natural context of living cells. With these advances, researchers are beginning to shed light on when, where, and to what degree mRNA are translated with single-molecule precision. These works provide insight into the heterogeneity of translation amongst single transcripts, behavior that is averaged out in complementary bulk assays. In this review, we discuss the rapidly maturing field of live-cell, single-mRNA imaging of translation, beginning with a brief overview of recent technological advances. The remainder of the review focuses on the new biological insights gained from these technologies. We conclude with a discussion of the future of this technology.
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Affiliation(s)
- Charlotte A Cialek
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Amanda L Koch
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Gabriel Galindo
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Timothy J Stasevich
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA; World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 2268503, Japan.
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23
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Aguilera LU, Raymond W, Fox ZR, May M, Djokic E, Morisaki T, Stasevich TJ, Munsky B. Computational design and interpretation of single-RNA translation experiments. PLoS Comput Biol 2019; 15:e1007425. [PMID: 31618265 PMCID: PMC6816579 DOI: 10.1371/journal.pcbi.1007425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 10/28/2019] [Accepted: 09/19/2019] [Indexed: 01/18/2023] Open
Abstract
Advances in fluorescence microscopy have introduced new assays to quantify live-cell translation dynamics at single-RNA resolution. We introduce a detailed, yet efficient sequence-based stochastic model that generates realistic synthetic data for several such assays, including Fluorescence Correlation Spectroscopy (FCS), ribosome Run-Off Assays (ROA) after Harringtonine application, and Fluorescence Recovery After Photobleaching (FRAP). We simulate these experiments under multiple imaging conditions and for thousands of human genes, and we evaluate through simulations which experiments are most likely to provide accurate estimates of elongation kinetics. Finding that FCS analyses are optimal for both short and long length genes, we integrate our model with experimental FCS data to capture the nascent protein statistics and temporal dynamics for three human genes: KDM5B, β-actin, and H2B. Finally, we introduce a new open-source software package, RNA Sequence to NAscent Protein Simulator (rSNAPsim), to easily simulate the single-molecule translation dynamics of any gene sequence for any of these assays and for different assumptions regarding synonymous codon usage, tRNA level modifications, or ribosome pauses. rSNAPsim is implemented in Python and is available at: https://github.com/MunskyGroup/rSNAPsim.git.
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Affiliation(s)
- Luis U. Aguilera
- Department of Chemical and Biological Engineering, Colorado State University Fort Collins, Colorado, United States of America
| | - William Raymond
- Department of Chemical and Biological Engineering, Colorado State University Fort Collins, Colorado, United States of America
- School of Biomedical Engineering, Colorado State University Fort Collins, Colorado, United States of America
| | - Zachary R. Fox
- School of Biomedical Engineering, Colorado State University Fort Collins, Colorado, United States of America
| | - Michael May
- School of Biomedical Engineering, Colorado State University Fort Collins, Colorado, United States of America
| | - Elliot Djokic
- School of Biomedical Engineering, Colorado State University Fort Collins, Colorado, United States of America
| | - Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado, United States of America
| | - Timothy J. Stasevich
- Department of Biochemistry and Molecular Biology and Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado, United States of America
- Cell Biology Unit, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama, Kanagawa, Japan
| | - Brian Munsky
- Department of Chemical and Biological Engineering, Colorado State University Fort Collins, Colorado, United States of America
- School of Biomedical Engineering, Colorado State University Fort Collins, Colorado, United States of America
- * E-mail:
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24
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Zhao N, Kamijo K, Fox PD, Oda H, Morisaki T, Sato Y, Kimura H, Stasevich TJ. A genetically encoded probe for imaging nascent and mature HA-tagged proteins in vivo. Nat Commun 2019; 10:2947. [PMID: 31270320 PMCID: PMC6610143 DOI: 10.1038/s41467-019-10846-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/29/2019] [Indexed: 01/07/2023] Open
Abstract
To expand the toolbox of imaging in living cells, we have engineered a single-chain variable fragment binding the linear HA epitope with high affinity and specificity in vivo. The resulting probe, called the HA frankenbody, can light up in multiple colors HA-tagged nuclear, cytoplasmic, membrane, and mitochondrial proteins in diverse cell types. The HA frankenbody also enables state-of-the-art single-molecule experiments in living cells, which we demonstrate by tracking single HA-tagged histones in U2OS cells and single mRNA translation dynamics in both U2OS cells and neurons. Together with the SunTag, we also track two mRNA species simultaneously to demonstrate comparative single-molecule studies of translation can now be done with genetically encoded tools alone. Finally, we use the HA frankenbody to precisely quantify the expression of HA-tagged proteins in developing zebrafish embryos. The versatility of the HA frankenbody makes it a powerful tool for imaging protein dynamics in vivo.
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Affiliation(s)
- Ning Zhao
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Kouta Kamijo
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
| | - Philip D Fox
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Haruka Oda
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
| | - Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Yuko Sato
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
| | - Hiroshi Kimura
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
- World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA.
- World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8503, Japan.
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25
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Lyon K, Aguilera LU, Morisaki T, Munsky B, Stasevich TJ. Live-Cell Single RNA Imaging Reveals Bursts of Translational Frameshifting. Mol Cell 2019; 75:172-183.e9. [PMID: 31178355 DOI: 10.1016/j.molcel.2019.05.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/14/2019] [Accepted: 04/30/2019] [Indexed: 11/25/2022]
Abstract
Ribosomal frameshifting during the translation of RNA is implicated in human disease and viral infection. While previous work has uncovered many details about single RNA frameshifting kinetics in vitro, little is known about how single RNA frameshift in living systems. To confront this problem, we have developed technology to quantify live-cell single RNA translation dynamics in frameshifted open reading frames. Applying this technology to RNA encoding the HIV-1 frameshift sequence reveals a small subset (∼8%) of the translating pool robustly frameshift. Frameshifting RNA are translated at similar rates as non-frameshifting RNA (∼3 aa/s) and can continuously frameshift for more than four rounds of translation. Fits to a bursty model of frameshifting constrain frameshifting kinetic rates and demonstrate how ribosomal traffic jams contribute to the persistence of the frameshifting state. These data provide insight into retroviral frameshifting and could lead to alternative strategies to perturb the process in living cells.
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Affiliation(s)
- Kenneth Lyon
- Department of Biochemistry and Molecular Biology, Institute of Genome Architecture and Function, Colorado State University, Fort Collins, CO 80523, USA
| | - Luis U Aguilera
- Department of Chemical and Biological Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology, Institute of Genome Architecture and Function, Colorado State University, Fort Collins, CO 80523, USA
| | - Brian Munsky
- Department of Chemical and Biological Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Biology, Institute of Genome Architecture and Function, Colorado State University, Fort Collins, CO 80523, USA; World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan.
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26
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Chao JA, Lionnet T. Imaging the Life and Death of mRNAs in Single Cells. Cold Spring Harb Perspect Biol 2018; 10:10/12/a032086. [PMID: 30510061 DOI: 10.1101/cshperspect.a032086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RNA plays a central role in gene expression from its transcription in the nucleus through translation and degradation in the cytoplasm. Technological advances in fluorescent microscopy and labeling methodologies have made it possible to detect single molecules of RNA in both fixed and living cells. Here, we focus on the recent developments in RNA imaging that have allowed quantitatively measuring the lives of individual transcripts from birth to death and all the events in between in single cells and tissues. Direct observation of RNAs within their native cellular environment has revealed a complex layer of spatial and temporal regulation that has profoundly impacted our understanding of RNA biology.
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Affiliation(s)
- Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Timothée Lionnet
- Institute for Systems Genetics, Department of Cell Biology, NYU Langone Health, New York, New York 10016
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