1
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Zuniga G, Frost B. Selective neuronal vulnerability to deficits in RNA processing. Prog Neurobiol 2023; 229:102500. [PMID: 37454791 DOI: 10.1016/j.pneurobio.2023.102500] [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: 05/02/2023] [Revised: 06/30/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Emerging evidence indicates that errors in RNA processing can causally drive neurodegeneration. Given that RNA produced from expressed genes of all cell types undergoes processing (splicing, polyadenylation, 5' capping, etc.), the particular vulnerability of neurons to deficits in RNA processing calls for careful consideration. The activity-dependent transcriptome remodeling associated with synaptic plasticity in neurons requires rapid, multilevel post-transcriptional RNA processing events that provide additional opportunities for dysregulation and consequent introduction or persistence of errors in RNA transcripts. Here we review the accumulating evidence that neurons have an enhanced propensity for errors in RNA processing alongside grossly insufficient defenses to clear misprocessed RNA compared to other cell types. Additionally, we explore how tau, a microtubule-associated protein implicated in Alzheimer's disease and related tauopathies, contributes to deficits in RNA processing and clearance.
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Affiliation(s)
- Gabrielle Zuniga
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Bess Frost
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA.
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2
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Di Liegro CM, Schiera G, Schirò G, Di Liegro I. RNA-Binding Proteins as Epigenetic Regulators of Brain Functions and Their Involvement in Neurodegeneration. Int J Mol Sci 2022; 23:ijms232314622. [PMID: 36498959 PMCID: PMC9739182 DOI: 10.3390/ijms232314622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022] Open
Abstract
A central aspect of nervous system development and function is the post-transcriptional regulation of mRNA fate, which implies time- and site-dependent translation, in response to cues originating from cell-to-cell crosstalk. Such events are fundamental for the establishment of brain cell asymmetry, as well as of long-lasting modifications of synapses (long-term potentiation: LTP), responsible for learning, memory, and higher cognitive functions. Post-transcriptional regulation is in turn dependent on RNA-binding proteins that, by recognizing and binding brief RNA sequences, base modifications, or secondary/tertiary structures, are able to control maturation, localization, stability, and translation of the transcripts. Notably, most RBPs contain intrinsically disordered regions (IDRs) that are thought to be involved in the formation of membrane-less structures, probably due to liquid-liquid phase separation (LLPS). Such structures are evidenced as a variety of granules that contain proteins and different classes of RNAs. The other side of the peculiar properties of IDRs is, however, that, under altered cellular conditions, they are also prone to form aggregates, as observed in neurodegeneration. Interestingly, RBPs, as part of both normal and aggregated complexes, are also able to enter extracellular vesicles (EVs), and in doing so, they can also reach cells other than those that produced them.
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Affiliation(s)
- Carlo Maria Di Liegro
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche) (STEBICEF), University of Palermo, 90128 Palermo, Italy
| | - Gabriella Schiera
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche) (STEBICEF), University of Palermo, 90128 Palermo, Italy
| | - Giuseppe Schirò
- Department of Biomedicine, Neurosciences and Advanced Diagnostics (Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata) (Bi.N.D.), University of Palermo, 90127 Palermo, Italy
| | - Italia Di Liegro
- Department of Biomedicine, Neurosciences and Advanced Diagnostics (Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata) (Bi.N.D.), University of Palermo, 90127 Palermo, Italy
- Correspondence: ; Tel.: +39-091-238-97 (ext. 415/446)
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3
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Petrić Howe M, Crerar H, Neeves J, Harley J, Tyzack GE, Klein P, Ramos A, Patani R, Luisier R. Physiological intron retaining transcripts in the cytoplasm abound during human motor neurogenesis. Genome Res 2022; 32:1808-1825. [PMID: 36180233 PMCID: PMC9712626 DOI: 10.1101/gr.276898.122] [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: 05/03/2022] [Accepted: 09/16/2022] [Indexed: 11/24/2022]
Abstract
Intron retention (IR) is now recognized as a dominant splicing event during motor neuron (MN) development; however, the role and regulation of intron-retaining transcripts (IRTs) localized to the cytoplasm remain particularly understudied. Here we show that IR is a physiological process that is spatiotemporally regulated during MN lineage restriction and that IRTs in the cytoplasm are detected in as many as 13% (n = 2297) of the genes expressed during this process. We identify a major class of cytoplasmic IRTs that are not associated with reduced expression of their own genes but instead show a high capacity for RNA-binding protein and miRNA occupancy. Finally, we show that ALS-causing VCP mutations lead to a selective increase in cytoplasmic abundance of this particular class of IRTs, which in turn temporally coincides with an increase in the nuclear expression level of predicted miRNA target genes. Altogether, our study identifies a previously unrecognized class of cytoplasmic intronic sequences with potential regulatory function beyond gene expression.
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Affiliation(s)
- Marija Petrić Howe
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Hamish Crerar
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Jacob Neeves
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Jasmine Harley
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Giulia E Tyzack
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Pierre Klein
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Research Department of Structural and Molecular Biology, University College London, London WC1E 6XA, United Kingdom
| | - Andres Ramos
- Research Department of Structural and Molecular Biology, University College London, London WC1E 6XA, United Kingdom
| | - Rickie Patani
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, United Kingdom
| | - Raphaëlle Luisier
- Idiap Research Institute, Genomics and Health Informatics, CH-1920 Martigny, Switzerland
- SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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4
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Miao Z, Humphreys BD, McMahon AP, Kim J. Multi-omics integration in the age of million single-cell data. Nat Rev Nephrol 2021; 17:710-724. [PMID: 34417589 PMCID: PMC9191639 DOI: 10.1038/s41581-021-00463-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2021] [Indexed: 02/06/2023]
Abstract
An explosion in single-cell technologies has revealed a previously underappreciated heterogeneity of cell types and novel cell-state associations with sex, disease, development and other processes. Starting with transcriptome analyses, single-cell techniques have extended to multi-omics approaches and now enable the simultaneous measurement of data modalities and spatial cellular context. Data are now available for millions of cells, for whole-genome measurements and for multiple modalities. Although analyses of such multimodal datasets have the potential to provide new insights into biological processes that cannot be inferred with a single mode of assay, the integration of very large, complex, multimodal data into biological models and mechanisms represents a considerable challenge. An understanding of the principles of data integration and visualization methods is required to determine what methods are best applied to a particular single-cell dataset. Each class of method has advantages and pitfalls in terms of its ability to achieve various biological goals, including cell-type classification, regulatory network modelling and biological process inference. In choosing a data integration strategy, consideration must be given to whether the multi-omics data are matched (that is, measured on the same cell) or unmatched (that is, measured on different cells) and, more importantly, the overall modelling and visualization goals of the integrated analysis.
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Affiliation(s)
- Zhen Miao
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA,Graduate Group in Genomics and Computational Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Benjamin D. Humphreys
- Division of Nephrology, Department of Medicine, Washington University in St. Louis, St. Louis, MO, USA
| | - Andrew P. McMahon
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Junhyong Kim
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA,Graduate Group in Genomics and Computational Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,
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5
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Rajgor D, Welle TM, Smith KR. The Coordination of Local Translation, Membranous Organelle Trafficking, and Synaptic Plasticity in Neurons. Front Cell Dev Biol 2021; 9:711446. [PMID: 34336865 PMCID: PMC8317219 DOI: 10.3389/fcell.2021.711446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/14/2021] [Indexed: 12/16/2022] Open
Abstract
Neurons are highly complex polarized cells, displaying an extraordinary degree of spatial compartmentalization. At presynaptic and postsynaptic sites, far from the cell body, local protein synthesis is utilized to continually modify the synaptic proteome, enabling rapid changes in protein production to support synaptic function. Synapses undergo diverse forms of plasticity, resulting in long-term, persistent changes in synapse strength, which are paramount for learning, memory, and cognition. It is now well-established that local translation of numerous synaptic proteins is essential for many forms of synaptic plasticity, and much work has gone into deciphering the strategies that neurons use to regulate activity-dependent protein synthesis. Recent studies have pointed to a coordination of the local mRNA translation required for synaptic plasticity and the trafficking of membranous organelles in neurons. This includes the co-trafficking of RNAs to their site of action using endosome/lysosome “transports,” the regulation of activity-dependent translation at synapses, and the role of mitochondria in fueling synaptic translation. Here, we review our current understanding of these mechanisms that impact local translation during synaptic plasticity, providing an overview of these novel and nuanced regulatory processes involving membranous organelles in neurons.
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Affiliation(s)
- Dipen Rajgor
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Theresa M Welle
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
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6
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Díaz M, Mesa-Herrera F, Marín R. DHA and Its Elaborated Modulation of Antioxidant Defenses of the Brain: Implications in Aging and AD Neurodegeneration. Antioxidants (Basel) 2021; 10:antiox10060907. [PMID: 34205196 PMCID: PMC8228037 DOI: 10.3390/antiox10060907] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/06/2023] Open
Abstract
DHA (docosahexaenoic acid) is perhaps the most pleiotropic molecule in nerve cell biology. This long-chain highly unsaturated fatty acid has evolved to accomplish essential functions ranging from structural components allowing fast events in nerve cell membrane physiology to regulation of neurogenesis and synaptic function. Strikingly, the plethora of DHA effects has to take place within the hostile pro-oxidant environment of the brain parenchyma, which might suggest a molecular suicide. In order to circumvent this paradox, different molecular strategies have evolved during the evolution of brain cells to preserve DHA and to minimize the deleterious effects of its oxidation. In this context, DHA has emerged as a member of the “indirect antioxidants” family, the redox effects of which are not due to direct redox interactions with reactive species, but to modulation of gene expression within thioredoxin and glutathione antioxidant systems and related pathways. Weakening or deregulation of these self-protecting defenses orchestrated by DHA is associated with normal aging but also, more worryingly, with the development of neurodegenerative diseases. In the present review, we elaborate on the essential functions of DHA in the brain, including its role as indirect antioxidant, the selenium connection for proper antioxidant function and their changes during normal aging and in Alzheimer’s disease.
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Affiliation(s)
- Mario Díaz
- Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, School of Biology, Universidad de La Laguna, 38206 Tenerife, Spain;
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSP), Universidad de La Laguna, 38206 Tenerife, Spain
- Unidad Asociada ULL-CSIC “Fisiología y Biofísica de la Membrana Celular en Enfermedades Neurodegenerativas y Tumorales”, 38206 Tenerife, Spain;
- Correspondence:
| | - Fátima Mesa-Herrera
- Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, School of Biology, Universidad de La Laguna, 38206 Tenerife, Spain;
| | - Raquel Marín
- Unidad Asociada ULL-CSIC “Fisiología y Biofísica de la Membrana Celular en Enfermedades Neurodegenerativas y Tumorales”, 38206 Tenerife, Spain;
- Laboratory of Cellular Neurobiology, Department of Basic Medical Sciences, School of Medicine, Universidad de La Laguna, 38206 Tenerife, Spain
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7
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Tyzack GE, Neeves J, Crerar H, Klein P, Ziff O, Taha DM, Luisier R, Luscombe NM, Patani R. Aberrant cytoplasmic intron retention is a blueprint for RNA binding protein mislocalization in VCP-related amyotrophic lateral sclerosis. Brain 2021; 144:1985-1993. [PMID: 33693641 PMCID: PMC8370440 DOI: 10.1093/brain/awab078] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 12/22/2020] [Accepted: 01/06/2021] [Indexed: 12/11/2022] Open
Abstract
We recently described aberrantly increased cytoplasmic SFPQ intron-retaining transcripts (IRTs) and concurrent SFPQ protein mislocalization as new hallmarks of amyotrophic lateral sclerosis (ALS). However, the generalizability and potential roles of cytoplasmic IRTs in health and disease remain unclear. Here, using time-resolved deep sequencing of nuclear and cytoplasmic fractions of human induced pluripotent stem cells undergoing motor neurogenesis, we reveal that ALS-causing VCP gene mutations lead to compartment-specific aberrant accumulation of IRTs. Specifically, we identify >100 IRTs with increased cytoplasmic abundance in ALS samples. Furthermore, these aberrant cytoplasmic IRTs possess sequence-specific attributes and differential predicted binding affinity to RNA binding proteins. Remarkably, TDP-43, SFPQ and FUS—RNA binding proteins known for nuclear-to-cytoplasmic mislocalization in ALS—abundantly and specifically bind to this aberrant cytoplasmic pool of IRTs. Our data are therefore consistent with a novel role for cytoplasmic IRTs in regulating compartment-specific protein abundance. This study provides new molecular insight into potential pathomechanisms underlying ALS and highlights aberrant cytoplasmic IRTs as potential therapeutic targets.
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Affiliation(s)
- Giulia E Tyzack
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Jacob Neeves
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Hamish Crerar
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Pierre Klein
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Oliver Ziff
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Doaa M Taha
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK.,Zoology Department, Faculty of Science, Alexandria University, Alexandria 21511, Egypt
| | - Raphaëlle Luisier
- Genomics and Health Informatics Group, Idiap Research Institute, CH - 1920 Martigny, Switzerland
| | - Nicholas M Luscombe
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,UCL Genetics Institute, University College London, London, WC1E 6BT, UK.,Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - Rickie Patani
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.,Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
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8
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Alon S, Goodwin DR, Sinha A, Wassie AT, Chen F, Daugharthy ER, Bando Y, Kajita A, Xue AG, Marrett K, Prior R, Cui Y, Payne AC, Yao CC, Suk HJ, Wang R, Yu CCJ, Tillberg P, Reginato P, Pak N, Liu S, Punthambaker S, Iyer EPR, Kohman RE, Miller JA, Lein ES, Lako A, Cullen N, Rodig S, Helvie K, Abravanel DL, Wagle N, Johnson BE, Klughammer J, Slyper M, Waldman J, Jané-Valbuena J, Rozenblatt-Rosen O, Regev A, Church GM, Marblestone AH, Boyden ES. Expansion sequencing: Spatially precise in situ transcriptomics in intact biological systems. Science 2021; 371:eaax2656. [PMID: 33509999 PMCID: PMC7900882 DOI: 10.1126/science.aax2656] [Citation(s) in RCA: 173] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/13/2020] [Accepted: 11/20/2020] [Indexed: 12/12/2022]
Abstract
Methods for highly multiplexed RNA imaging are limited in spatial resolution and thus in their ability to localize transcripts to nanoscale and subcellular compartments. We adapt expansion microscopy, which physically expands biological specimens, for long-read untargeted and targeted in situ RNA sequencing. We applied untargeted expansion sequencing (ExSeq) to the mouse brain, which yielded the readout of thousands of genes, including splice variants. Targeted ExSeq yielded nanoscale-resolution maps of RNAs throughout dendrites and spines in the neurons of the mouse hippocampus, revealing patterns across multiple cell types, layer-specific cell types across the mouse visual cortex, and the organization and position-dependent states of tumor and immune cells in a human metastatic breast cancer biopsy. Thus, ExSeq enables highly multiplexed mapping of RNAs from nanoscale to system scale.
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Affiliation(s)
- Shahar Alon
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
- Faculty of Engineering, Gonda Brain Research Center and Institute of Nanotechnology, Bar-Ilan University, Ramat Gan, Israel
| | - Daniel R Goodwin
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
| | - Anubhav Sinha
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
- Harvard-MIT Program in Health Sciences and Technology, MIT, Cambridge, MA, USA
| | - Asmamaw T Wassie
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
- Department of Biological Engineering, MIT, Cambridge, MA, USA
| | - Fei Chen
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Evan R Daugharthy
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Boston, MA, USA
| | - Yosuke Bando
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- Kioxia Corporation, Minato-ku, Tokyo, Japan
| | | | - Andrew G Xue
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
| | | | | | - Yi Cui
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
| | - Andrew C Payne
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Chun-Chen Yao
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ho-Jun Suk
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
- Harvard-MIT Program in Health Sciences and Technology, MIT, Cambridge, MA, USA
| | - Ru Wang
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
| | - Chih-Chieh Jay Yu
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
- Department of Biological Engineering, MIT, Cambridge, MA, USA
| | - Paul Tillberg
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
| | - Paul Reginato
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- Department of Biological Engineering, MIT, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Boston, MA, USA
| | - Nikita Pak
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA
- McGovern Institute, MIT, Cambridge, MA, USA
- Department of Mechanical Engineering, MIT, Cambridge, MA, USA
| | - Songlei Liu
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Boston, MA, USA
| | - Sukanya Punthambaker
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Boston, MA, USA
| | - Eswar P R Iyer
- Wyss Institute for Biologically Inspired Engineering, Boston, MA, USA
| | - Richie E Kohman
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Boston, MA, USA
| | | | - Ed S Lein
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Ana Lako
- Center for Immuno-Oncology (CIO), Dana-Farber Cancer Institute, Boston, MA, USA
| | - Nicole Cullen
- Center for Immuno-Oncology (CIO), Dana-Farber Cancer Institute, Boston, MA, USA
| | - Scott Rodig
- Center for Immuno-Oncology (CIO), Dana-Farber Cancer Institute, Boston, MA, USA
| | - Karla Helvie
- Center for Cancer Genomics, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Daniel L Abravanel
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Nikhil Wagle
- Center for Cancer Genomics, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Bruce E Johnson
- Center for Cancer Genomics, Dana-Farber Cancer Institute, Boston, MA, USA
| | | | - Michal Slyper
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Julia Waldman
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | | | - Aviv Regev
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Department of Biology, MIT, Cambridge, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Wyss Institute for Biologically Inspired Engineering, Boston, MA, USA
| | | | - Edward S Boyden
- Department of Media Arts and Sciences, MIT, Cambridge, MA, USA.
- McGovern Institute, MIT, Cambridge, MA, USA
- Department of Biological Engineering, MIT, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Department of Biology, MIT, Cambridge, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA
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9
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Saini H, Bicknell AA, Eddy SR, Moore MJ. Free circular introns with an unusual branchpoint in neuronal projections. eLife 2019; 8:e47809. [PMID: 31697236 PMCID: PMC6879206 DOI: 10.7554/elife.47809] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 11/06/2019] [Indexed: 12/22/2022] Open
Abstract
The polarized structure of axons and dendrites in neuronal cells depends in part on RNA localization. Previous studies have looked at which polyadenylated RNAs are enriched in neuronal projections or at synapses, but less is known about the distribution of non-adenylated RNAs. By physically dissecting projections from cell bodies of primary rat hippocampal neurons and sequencing total RNA, we found an unexpected set of free circular introns with a non-canonical branchpoint enriched in neuronal projections. These introns appear to be tailless lariats that escape debranching. They lack ribosome occupancy, sequence conservation, and known localization signals, and their function, if any, is not known. Nonetheless, their enrichment in projections has important implications for our understanding of the mechanisms by which RNAs reach distal compartments of asymmetric cells.
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Affiliation(s)
- Harleen Saini
- RNA Therapeutics InstituteUniversity of Massachusetts Medical SchoolWorcesterUnited States
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, Harvard UniversityCambridgeUnited States
| | - Alicia A Bicknell
- RNA Therapeutics InstituteUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Sean R Eddy
- Department of Molecular and Cellular BiologyHoward Hughes Medical Institute, Harvard UniversityCambridgeUnited States
- John A Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeUnited States
| | - Melissa J Moore
- RNA Therapeutics InstituteUniversity of Massachusetts Medical SchoolWorcesterUnited States
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10
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Andreassi C, Crerar H, Riccio A. Post-transcriptional Processing of mRNA in Neurons: The Vestiges of the RNA World Drive Transcriptome Diversity. Front Mol Neurosci 2018; 11:304. [PMID: 30210293 PMCID: PMC6121099 DOI: 10.3389/fnmol.2018.00304] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/09/2018] [Indexed: 12/17/2022] Open
Abstract
Neurons are morphologically complex cells that rely on the compartmentalization of protein expression to develop and maintain their extraordinary cytoarchitecture. This formidable task is achieved, at least in part, by targeting mRNA to subcellular compartments where they are rapidly translated. mRNA transcripts are the conveyor of genetic information from DNA to the translational machinery, however, they are also endowed with additional functions linked to both the coding sequence (open reading frame, or ORF) and the flanking 5′ and 3′ untranslated regions (UTRs), that may harbor coding-independent functions. In this review, we will highlight recent evidences supporting new coding-dependent and -independent functions of mRNA and discuss how nuclear and cytoplasmic post-transcriptional modifications of mRNA contribute to localization and translation in mammalian cells with specific emphasis on neurons. We also describe recently developed techniques that can be employed to study RNA dynamics at subcellular level in eukaryotic cells in developing and regenerating neurons.
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Affiliation(s)
- Catia Andreassi
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Hamish Crerar
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Antonella Riccio
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
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11
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Jackson DP, Ting JH, Pozniak PD, Meurice C, Schleidt SS, Dao A, Lee AH, Klinman E, Jordan-Sciutto KL. Identification and characterization of two novel alternatively spliced E2F1 transcripts in the rat CNS. Mol Cell Neurosci 2018; 92:1-11. [PMID: 29936143 DOI: 10.1016/j.mcn.2018.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 06/05/2018] [Accepted: 06/19/2018] [Indexed: 10/28/2022] Open
Abstract
E2F1 is a transcription factor classically known to regulate G0/G1 to S phase progression in the cell cycle. In addition, E2F1 also regulates a wide range of apoptotic genes and thus has been well studied in the context of neuronal death and neurodegenerative diseases. However, its function and regulation in the mature central nervous system are not well understood. Alternative splicing is a well-conserved post-transcriptional mechanism common in cells of the CNS and is necessary to generate diverse functional modifications to RNA or protein products from genes. Heretofore, physiologically significant alternatively spliced E2F1 transcripts have not been reported. In the present study, we report the identification of two novel alternatively spliced E2F1 transcripts: E2F1b, an E2F1 transcript retaining intron 5, and E2F1c, an E2F1 transcript excluding exon 6. These alternatively spliced transcripts are observed in the brain and neural cell types including neurons, astrocytes, and undifferentiated oligodendrocytes. The expression of these E2F1 transcripts is distinct during maturation of primary hippocampal neuroglial cells. Pharmacologically-induced global translation inhibition with cycloheximide, anisomycin or thapsigargin lead to significantly reduced expression of E2F1a, E2F1b and E2F1c. Conversely, increasing neuronal activity by elevating the concentration of potassium chloride selectively increased the expression of E2F1b. Furthermore, experiments expressing these variants in vitro show the transcripts can be translated to generate a protein product. Taken together, our data suggest that the alternatively spliced E2F1 transcript behave differently than the E2F1a transcript, and our results provide a foundation for future investigation of the function of E2F1 splice variants in the CNS.
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Affiliation(s)
- Dan P Jackson
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA
| | - Jenhao H Ting
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA
| | - Paul D Pozniak
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA
| | - Claire Meurice
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephanie S Schleidt
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA
| | - Anh Dao
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA
| | - Amy H Lee
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA
| | - Eva Klinman
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kelly L Jordan-Sciutto
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Philadelphia, PA 19104, USA.
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12
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Benoit Bouvrette LP, Cody NAL, Bergalet J, Lefebvre FA, Diot C, Wang X, Blanchette M, Lécuyer E. CeFra-seq reveals broad asymmetric mRNA and noncoding RNA distribution profiles in Drosophila and human cells. RNA (NEW YORK, N.Y.) 2018; 24:98-113. [PMID: 29079635 PMCID: PMC5733575 DOI: 10.1261/rna.063172.117] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/13/2017] [Indexed: 05/26/2023]
Abstract
Cells are highly asymmetrical, a feature that relies on the sorting of molecular constituents, including proteins, lipids, and nucleic acids, to distinct subcellular locales. The localization of RNA molecules is an important layer of gene regulation required to modulate localized cellular activities, although its global prevalence remains unclear. We combine biochemical cell fractionation with RNA-sequencing (CeFra-seq) analysis to assess the prevalence and conservation of RNA asymmetric distribution on a transcriptome-wide scale in Drosophila and human cells. This approach reveals that the majority (∼80%) of cellular RNA species are asymmetrically distributed, whether considering coding or noncoding transcript populations, in patterns that are broadly conserved evolutionarily. Notably, a large number of Drosophila and human long noncoding RNAs and circular RNAs display enriched levels within specific cytoplasmic compartments, suggesting that these RNAs fulfill extra-nuclear functions. Moreover, fraction-specific mRNA populations exhibit distinctive sequence characteristics. Comparative analysis of mRNA fractionation profiles with that of their encoded proteins reveals a general lack of correlation in subcellular distribution, marked by strong cases of asymmetry. However, coincident distribution profiles are observed for mRNA/protein pairs related to a variety of functional protein modules, suggesting complex regulatory inputs of RNA localization to cellular organization.
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Affiliation(s)
- Louis Philip Benoit Bouvrette
- Institut de Recherches Clinique de Montréal (IRCM), Montréal H2W 1R7, Canada
- Département de Biochimie, Université de Montréal, Montréal H3C 3J7, Canada
| | - Neal A L Cody
- Institut de Recherches Clinique de Montréal (IRCM), Montréal H2W 1R7, Canada
| | - Julie Bergalet
- Institut de Recherches Clinique de Montréal (IRCM), Montréal H2W 1R7, Canada
| | - Fabio Alexis Lefebvre
- Institut de Recherches Clinique de Montréal (IRCM), Montréal H2W 1R7, Canada
- Département de Biochimie, Université de Montréal, Montréal H3C 3J7, Canada
| | - Cédric Diot
- Institut de Recherches Clinique de Montréal (IRCM), Montréal H2W 1R7, Canada
- Département de Biochimie, Université de Montréal, Montréal H3C 3J7, Canada
| | - Xiaofeng Wang
- Institut de Recherches Clinique de Montréal (IRCM), Montréal H2W 1R7, Canada
| | - Mathieu Blanchette
- McGill School of Computer Science, McGill University, Montréal H3A 0E9, Canada
| | - Eric Lécuyer
- Institut de Recherches Clinique de Montréal (IRCM), Montréal H2W 1R7, Canada
- Département de Biochimie, Université de Montréal, Montréal H3C 3J7, Canada
- Division of Experimental Medicine, McGill University, Montréal H4A 3J1, Canada
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13
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Lefebvre FA, Cody NA, Bouvrette LPB, Bergalet J, Wang X, Lécuyer E. CeFra-seq: Systematic mapping of RNA subcellular distribution properties through cell fractionation coupled to deep-sequencing. Methods 2017; 126:138-148. [DOI: 10.1016/j.ymeth.2017.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/18/2017] [Accepted: 05/21/2017] [Indexed: 12/18/2022] Open
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14
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Lein ES, Belgard TG, Hawrylycz M, Molnár Z. Transcriptomic Perspectives on Neocortical Structure, Development, Evolution, and Disease. Annu Rev Neurosci 2017; 40:629-652. [PMID: 28661727 DOI: 10.1146/annurev-neuro-070815-013858] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cerebral cortex is the source of our most complex cognitive capabilities and a vulnerable target of many neurological and neuropsychiatric disorders. Transcriptomics offers a new approach to understanding the cortex at the level of its underlying genetic code, and rapid technological advances have propelled this field to the high-throughput study of the complete set of transcribed genes at increasingly fine resolution to the level of individual cells. These tools have revealed features of the genetic architecture of adult cortical areas, layers, and cell types, as well as spatiotemporal patterning during development. This has allowed a fresh look at comparative anatomy as well, illustrating surprisingly large differences between mammals while at the same time revealing conservation of some features from avians to mammals. Finally, transcriptomics is fueling progress in understanding the causes of neurodevelopmental diseases such as autism, linking genetic association studies to specific molecular pathways and affected brain regions.
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Affiliation(s)
- Ed S Lein
- Allen Institute for Brain Science, Seattle, Washington 98103; ,
| | | | | | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, United Kingdom;
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15
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Martin S, Bellora N, González-Vallinas J, Irimia M, Chebli K, de Toledo M, Raabe M, Eyras E, Urlaub H, Blencowe BJ, Tazi J. Preferential binding of a stable G3BP ribonucleoprotein complex to intron-retaining transcripts in mouse brain and modulation of their expression in the cerebellum. J Neurochem 2016; 139:349-368. [PMID: 27513819 DOI: 10.1111/jnc.13768] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/02/2016] [Accepted: 08/02/2016] [Indexed: 12/13/2022]
Abstract
Neuronal granules play an important role in the localization and transport of translationally silenced messenger ribonucleoproteins in neurons. Among the factors associated with these granules, the RNA-binding protein G3BP1 (stress-granules assembly factor) is involved in neuronal plasticity and is induced in Alzheimer's disease. We immunopurified a stable complex containing G3BP1 from mouse brain and performed high-throughput sequencing and cross-linking immunoprecipitation to identify the associated RNAs. The G3BP-complex contained the deubiquitinating protease USP10, CtBP1 and the RNA-binding proteins Caprin-1, G3BP2a and splicing factor proline and glutamine rich, or PSF. The G3BP-complex binds preferentially to transcripts that retain introns, and to non-coding sequences like 3'-untranslated region and long non-coding RNAs. Specific transcripts with retained introns appear to be enriched in the cerebellum compared to the rest of the brain and G3BP1 depletion decreased this intron retention in the cerebellum of G3BP1 knockout mice. Among the enriched transcripts, we found an overrepresentation of genes involved in synaptic transmission, especially glutamate-related neuronal transmission. Notably, G3BP1 seems to repress the expression of the mature Grm5 (metabotropic glutamate receptor 5) transcript, by promoting the retention of an intron in the immature transcript in the cerebellum. Our results suggest that G3BP is involved in a new functional mechanism to regulate non-coding RNAs including intron-retaining transcripts, and thus have broad implications for neuronal gene regulation, where intron retention is widespread.
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Affiliation(s)
- Sophie Martin
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France
| | - Nicolas Bellora
- Computational Genomics Group Universitat Pompeu Fabra PRBB, Barcelona, Spain.,Laboratorio de Microbiología Aplicada y Biotecnología, Instituto Andino-Patagónico de Tecnologías Biológicas y Geoambientales (IPATEC), CONICET - UNComahue, Bariloche, Argentina
| | | | - Manuel Irimia
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Karim Chebli
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France
| | - Marion de Toledo
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France
| | - Monika Raabe
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Eduardo Eyras
- Computational Genomics Group Universitat Pompeu Fabra PRBB, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, Barcelona, Spain
| | - Henning Urlaub
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ben J Blencowe
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Jamal Tazi
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR5535, Montpellier, France.
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16
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Altered mRNA Splicing in SMN-Depleted Motor Neuron-Like Cells. PLoS One 2016; 11:e0163954. [PMID: 27736905 PMCID: PMC5063418 DOI: 10.1371/journal.pone.0163954] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 09/16/2016] [Indexed: 11/23/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an intractable neurodegenerative disease afflicting 1 in 6–10,000 live births. One of the key functions of the SMN protein is regulation of spliceosome assembly. Reduced levels of the SMN protein that are observed in SMA have been shown to result in aberrant mRNA splicing. SMN-dependent mis-spliced transcripts in motor neurons may cause stresses that are particularly harmful and may serve as potential targets for the treatment of motor neuron disease or as biomarkers in the SMA patient population. We performed deep RNA sequencing using motor neuron-like NSC-34 cells to screen for SMN-dependent mRNA processing changes that occur following acute depletion of SMN. We identified SMN-dependent splicing changes, including an intron retention event that results in the production of a truncated Rit1 transcript. This intron-retained transcript is stable and is mis-spliced in spinal cord from symptomatic SMA mice. Constitutively active Rit1 ameliorated the neurite outgrowth defect in SMN depleted NSC-34 cells, while expression of the truncated protein product of the mis-spliced Rit1 transcript inhibited neurite extension. These results reveal new insights into the biological consequence of SMN-dependent splicing in motor neuron-like cells.
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17
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Berto S, Usui N, Konopka G, Fogel BL. ELAVL2-regulated transcriptional and splicing networks in human neurons link neurodevelopment and autism. Hum Mol Genet 2016; 25:2451-2464. [PMID: 27260404 DOI: 10.1093/hmg/ddw110] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/01/2016] [Accepted: 04/04/2016] [Indexed: 01/31/2023] Open
Abstract
The role of post-transcriptional gene regulation in human brain development and neurodevelopmental disorders remains mostly uncharacterized. ELAV-like RNA-binding proteins (RNAbps) are a family of proteins that regulate several aspects of neuronal function including neuronal excitability and synaptic transmission, both critical to the normal function of the brain in cognition and behavior. Here, we identify the downstream neuronal transcriptional and splicing networks of ELAVL2, an RNAbp with previously unknown function in the brain. Expression of ELAVL2 was reduced in human neurons and RNA-sequencing was utilized to identify networks of differentially expressed and alternatively spliced genes resulting from haploinsufficient levels of ELAVL2. These networks contain a number of autism-relevant genes as well as previously identified targets of other important RNAbps implicated in autism spectrum disorder (ASD) including RBFOX1 and FMRP. ELAVL2-regulated co-expression networks are also enriched for neurodevelopmental and synaptic genes, and include genes with human-specific patterns of expression in the frontal pole. Together, these data suggest that ELAVL2 regulation of transcript expression is critical for neuronal function and clinically relevant to ASD.
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Affiliation(s)
- Stefano Berto
- Department of Neuroscience, University of Texas Southwestern Medical School, 5323 Harry Hines Blvd, ND4.300, Dallas, TX 75390-9111, USA
| | - Noriyoshi Usui
- Department of Neuroscience, University of Texas Southwestern Medical School, 5323 Harry Hines Blvd, ND4.300, Dallas, TX 75390-9111, USA
| | - Genevieve Konopka
- Department of Neuroscience, University of Texas Southwestern Medical School, 5323 Harry Hines Blvd, ND4.300, Dallas, TX 75390-9111, USA
| | - Brent L Fogel
- Program in Neurogenetics and Departments of Neurology and Human Genetics, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Gonda Room 1206, Los Angeles, CA 90095, USA
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18
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Proteostasis and RNA Binding Proteins in Synaptic Plasticity and in the Pathogenesis of Neuropsychiatric Disorders. Neural Plast 2016; 2016:3857934. [PMID: 26904297 PMCID: PMC4745388 DOI: 10.1155/2016/3857934] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/30/2015] [Indexed: 12/30/2022] Open
Abstract
Decades of research have demonstrated that rapid alterations in protein abundance are required for synaptic plasticity, a cellular correlate for learning and memory. Control of protein abundance, known as proteostasis, is achieved across a complex neuronal morphology that includes a tortuous axon as well as an extensive dendritic arbor supporting thousands of individual synaptic compartments. To regulate the spatiotemporal synthesis of proteins, neurons must efficiently coordinate the transport and metabolism of mRNAs. Among multiple levels of regulation, transacting RNA binding proteins (RBPs) control proteostasis by binding to mRNAs and mediating their transport and translation in response to synaptic activity. In addition to synthesis, protein degradation must be carefully balanced for optimal proteostasis, as deviations resulting in excess or insufficient abundance of key synaptic factors produce pathologies. As such, mutations in components of the proteasomal or translational machinery, including RBPs, have been linked to the pathogenesis of neurological disorders such as Fragile X Syndrome (FXS), Fragile X Tremor Ataxia Syndrome (FXTAS), and Autism Spectrum Disorders (ASD). In this review, we summarize recent scientific findings, highlight ongoing questions, and link basic molecular mechanisms to the pathogenesis of common neuropsychiatric disorders.
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19
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Harbom LJ, Chronister WD, McConnell MJ. Single neuron transcriptome analysis can reveal more than cell type classification: Does it matter if every neuron is unique? Bioessays 2016; 38:157-61. [PMID: 26749010 PMCID: PMC4852373 DOI: 10.1002/bies.201500097] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A recent single cell mRNA sequencing study by Dueck et al. compares neuronal transcriptomes to the transcriptomes of adipocytes and cardiomyocytes. Single cell omic approaches such as those used by the authors are at the leading edge of molecular and biophysical measurement. Many groups are currently employing single cell sequencing approaches to understand cellular heterogeneity in cancer and during normal development. These single cell approaches also are beginning to address long-standing questions regarding nervous system diversity. Beyond an innate interest in cataloging cell type diversity in the brain, single cell neuronal diversity has important implications for neurotypic neural circuit function and for neurological disease. Herein, we review the authors' methods and findings, which most notably include evidence of unique expression profiles in some single neurons.
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Affiliation(s)
- Lise J Harbom
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia.,Neurosciences Graduate Program, University of Virginia School of Medicine, Charlottesville, Virginia
| | - William D Chronister
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia.,Biomedical Sciences Graduate Program, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Michael J McConnell
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia.,Neurosciences Graduate Program, University of Virginia School of Medicine, Charlottesville, Virginia.,Biomedical Sciences Graduate Program, University of Virginia School of Medicine, Charlottesville, Virginia.,Center for Brain Immunology and Glia, University of Virginia School of Medicine, Charlottesville, Virginia
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20
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Affiliation(s)
- Justin J.-L. Wong
- Gene and Stem Cell Therapy Program, Centenary Institute; Royal Prince Alfred Hospital; Camperdown Australia
- Sydney Medical School; University of Sydney; Camperdown Australia
| | - Amy Y. M. Au
- Gene and Stem Cell Therapy Program, Centenary Institute; Royal Prince Alfred Hospital; Camperdown Australia
- Sydney Medical School; University of Sydney; Camperdown Australia
| | - William Ritchie
- Gene and Stem Cell Therapy Program, Centenary Institute; Royal Prince Alfred Hospital; Camperdown Australia
- Sydney Medical School; University of Sydney; Camperdown Australia
- Department of Bioinformatics, Centenary Institute; Royal Prince Alfred Hospital; Camperdown Australia
| | - John E. J. Rasko
- Gene and Stem Cell Therapy Program, Centenary Institute; Royal Prince Alfred Hospital; Camperdown Australia
- Sydney Medical School; University of Sydney; Camperdown Australia
- Cell and Molecular Therapies; Royal Prince Alfred Hospital; Camperdown Australia
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21
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Abstract
A majority of messenger RNA precursors (pre-mRNAs) in the higher eukaryotes undergo alternative splicing to generate more than one mature product. By targeting the open reading frame region this process increases diversity of protein isoforms beyond the nominal coding capacity of the genome. However, alternative splicing also frequently controls output levels and spatiotemporal features of cellular and organismal gene expression programs. Here we discuss how these non-coding functions of alternative splicing contribute to development through regulation of mRNA stability, translational efficiency and cellular localization.
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22
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Casañas-Sánchez V, Pérez JA, Fabelo N, Quinto-Alemany D, Díaz ML. Docosahexaenoic (DHA) modulates phospholipid-hydroperoxide glutathione peroxidase (Gpx4) gene expression to ensure self-protection from oxidative damage in hippocampal cells. Front Physiol 2015; 6:203. [PMID: 26257655 PMCID: PMC4510835 DOI: 10.3389/fphys.2015.00203] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 07/03/2015] [Indexed: 01/31/2023] Open
Abstract
Docosahexaenoic acid (DHA, 22:6n-3) is a unique polyunsaturated fatty acid particularly abundant in nerve cell membrane phospholipids. DHA is a pleiotropic molecule that, not only modulates the physicochemical properties and architecture of neuronal plasma membrane, but it is also involved in multiple facets of neuronal biology, from regulation of synaptic function to neuroprotection and modulation of gene expression. As a highly unsaturated fatty acid due to the presence of six double bonds, DHA is susceptible for oxidation, especially in the highly pro-oxidant environment of brain parenchyma. We have recently reported the ability of DHA to regulate the transcriptional program controlling neuronal antioxidant defenses in a hippocampal cell line, especially the glutathione/glutaredoxin system. Within this antioxidant system, DHA was particularly efficient in triggering the upregulation of Gpx4 gene, which encodes for the nuclear, cytosolic, and mitochondrial isoforms of phospholipid-hydroperoxide glutathione peroxidase (PH-GPx/GPx4), the main enzyme protecting cell membranes against lipid peroxidation and capable to reduce oxidized phospholipids in situ. We show here that this novel property of DHA is also significant in the hippocampus of wild-type mice and, to a lesser extent in APP/PS1 transgenic mice, a familial model of Alzheimer's disease. By doing this, DHA stimulates a mechanism to self-protect from oxidative damage even in the neuronal scenario of high aerobic metabolism and in the presence of elevated levels of transition metals, which inevitably favor the generation of reactive oxygen species. Noticeably, DHA also upregulated a Gpx4 CIRT (Cytoplasmic Intron-sequence Retaining Transcripts), a novel Gpx4 splicing variant, harboring part of the first intronic region, which according to the “sentinel RNA hypothesis” would expand the ability of Gpx4 (and DHA) to provide neuronal antioxidant defense independently of conventional nuclear splicing in cellular compartments, like dendritic zones, located away from nuclear compartment. We discuss here, the crucial role of this novel transcriptional regulation triggered by DHA in the context of normal and pathological hippocampal cell.
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Affiliation(s)
- Verónica Casañas-Sánchez
- Department of Genetics, University Institute of Tropical Diseases and Public Health, University of La Laguna La Laguna, Spain
| | - José A Pérez
- Department of Genetics, University Institute of Tropical Diseases and Public Health, University of La Laguna La Laguna, Spain
| | - Noemí Fabelo
- Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, University of La Laguna La Laguna, Spain
| | - David Quinto-Alemany
- Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, University of La Laguna La Laguna, Spain
| | - Mario L Díaz
- Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, University of La Laguna La Laguna, Spain
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23
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Nishida A, Minegishi M, Takeuchi A, Niba ETE, Awano H, Lee T, Iijima K, Takeshima Y, Matsuo M. Tissue- and case-specific retention of intron 40 in mature dystrophin mRNA. J Hum Genet 2015; 60:327-33. [PMID: 25833469 DOI: 10.1038/jhg.2015.24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/10/2015] [Accepted: 02/12/2015] [Indexed: 11/09/2022]
Abstract
The dystrophin gene, which is mutated in Duchenne muscular dystrophy (DMD), comprises 79 exons that show multiple alternative splicing events. Intron retention, a type of alternative splicing, may control gene expression. We examined intron retention in dystrophin introns by reverse-transcription PCR from skeletal muscle, focusing on the nine shortest (all <1000 bp), because these are more likely to be retained. Only one, intron 40, was retained in mRNA; sequencing revealed insertion of a complete intron 40 (851 nt) between exons 40 and 41. The intron 40 retention product accounted for 1.2% of the total product but had a premature stop codon at the fifth intronic codon. Intron 40 retention was most strongly observed in the kidney (36.6%) and was not obtained from the fetal liver, lung, spleen or placenta. This indicated that intron retention is a tissue-specific event whose level varies among tissues. In two DMD patients, intron 40 retention was observed in one patient but not in the other. Examination of splicing regulatory factors revealed that intron 40 had the highest guanine-cytosine content of all examined introns in a 30-nt segment at its 3' end. Further studies are needed to clarify the biological role of intron 40-retained dystrophin mRNA.
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Affiliation(s)
- Atsushi Nishida
- Department of Medical Rehabilitation, Faculty of Rehabilitation, Kobegakuin University, Kobe, Japan
| | - Maki Minegishi
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe, Japan
| | - Atsuko Takeuchi
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe, Japan
| | - Emma Tabe Eko Niba
- Department of Medical Rehabilitation, Faculty of Rehabilitation, Kobegakuin University, Kobe, Japan
| | - Hiroyuki Awano
- Department of Pediatrics, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoko Lee
- Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Graduate School of Medicine, Kobe University, Kobe, Japan
| | | | - Masafumi Matsuo
- Department of Medical Rehabilitation, Faculty of Rehabilitation, Kobegakuin University, Kobe, Japan
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24
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Middleton SA, Kim J. NoFold: RNA structure clustering without folding or alignment. RNA (NEW YORK, N.Y.) 2014; 20:1671-1683. [PMID: 25234928 PMCID: PMC4201820 DOI: 10.1261/rna.041913.113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 07/28/2014] [Indexed: 06/03/2023]
Abstract
Structures that recur across multiple different transcripts, called structure motifs, often perform a similar function-for example, recruiting a specific RNA-binding protein that then regulates translation, splicing, or subcellular localization. Identifying common motifs between coregulated transcripts may therefore yield significant insight into their binding partners and mechanism of regulation. However, as most methods for clustering structures are based on folding individual sequences or doing many pairwise alignments, this results in a tradeoff between speed and accuracy that can be problematic for large-scale data sets. Here we describe a novel method for comparing and characterizing RNA secondary structures that does not require folding or pairwise alignment of the input sequences. Our method uses the idea of constructing a distance function between two objects by their respective distances to a collection of empirical examples or models, which in our case consists of 1973 Rfam family covariance models. Using this as a basis for measuring structural similarity, we developed a clustering pipeline called NoFold to automatically identify and annotate structure motifs within large sequence data sets. We demonstrate that NoFold can simultaneously identify multiple structure motifs with an average sensitivity of 0.80 and precision of 0.98 and generally exceeds the performance of existing methods. We also perform a cross-validation analysis of the entire set of Rfam families, achieving an average sensitivity of 0.57. We apply NoFold to identify motifs enriched in dendritically localized transcripts and report 213 enriched motifs, including both known and novel structures.
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Affiliation(s)
- Sarah A Middleton
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Junhyong Kim
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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25
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Talhouarne GJS, Gall JG. Lariat intronic RNAs in the cytoplasm of Xenopus tropicalis oocytes. RNA (NEW YORK, N.Y.) 2014; 20:1476-87. [PMID: 25051970 PMCID: PMC4138330 DOI: 10.1261/rna.045781.114] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We previously demonstrated that the oocyte nucleus (germinal vesicle or GV) of Xenopus tropicalis contains a population of stable RNA molecules derived from the introns of most expressed genes. Here we show that similar stable intronic sequence (sis) RNAs occur in the oocyte cytoplasm. About 9000 cytoplasmic sisRNAs have been identified, all of which are resistant to the exonuclease RNase R. About half have been confirmed as lariat molecules and the rest are presumed to be lariats, whereas nuclear sisRNAs are a mixture of lariat and linear molecules. Cytoplasmic sisRNAs are more abundant on a molar basis than nuclear sisRNAs and are derived from short introns, mostly under 1 kb in length. Both nuclear and cytoplasmic sisRNAs are transmitted intact to the egg at GV breakdown and persist until at least the blastula stage of embryogenesis, when zygotic transcription begins. We compared cytoplasmic sisRNAs derived from orthologous genes of X. tropicalis and X. laevis, and found that the specific introns from which sisRNAs are derived are not conserved. The existence of sisRNAs in the cytoplasm of the oocyte, their transmission to the fertilized egg, and their persistence during early embryogenesis suggest that they might play a regulatory role in mRNA translation.
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Affiliation(s)
- Gaëlle J S Talhouarne
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA Department of Biology, Mudd Hall, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Joseph G Gall
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA Department of Biology, Mudd Hall, Johns Hopkins University, Baltimore, Maryland 21218, USA
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26
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Casañas-Sánchez V, Pérez JA, Fabelo N, Herrera-Herrera AV, Fernández C, Marín R, González-Montelongo MC, Díaz M. Addition of docosahexaenoic acid, but not arachidonic acid, activates glutathione and thioredoxin antioxidant systems in murine hippocampal HT22 cells: potential implications in neuroprotection. J Neurochem 2014; 131:470-83. [DOI: 10.1111/jnc.12833] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 07/12/2014] [Accepted: 07/21/2014] [Indexed: 01/20/2023]
Affiliation(s)
- Verónica Casañas-Sánchez
- Department of Genetics; University Institute of Tropical Diseases and Public Health; University of La Laguna; Tenerife Spain
| | - José A. Pérez
- Department of Genetics; University Institute of Tropical Diseases and Public Health; University of La Laguna; Tenerife Spain
| | - Noemí Fabelo
- Laboratory of Membrane Physiology and Biophysics; Department of Animal Biology; University of La Laguna; Tenerife Spain
| | | | - Cecilia Fernández
- Laboratory of Cellular Neurobiology; Department of Physiology; University of La Laguna; Tenerife Spain
| | - Raquel Marín
- Laboratory of Cellular Neurobiology; Department of Physiology; University of La Laguna; Tenerife Spain
| | - María C. González-Montelongo
- Laboratory of Membrane Physiology and Biophysics; Department of Animal Biology; University of La Laguna; Tenerife Spain
| | - Mario Díaz
- Laboratory of Membrane Physiology and Biophysics; Department of Animal Biology; University of La Laguna; Tenerife Spain
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27
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Saliba AE, Westermann AJ, Gorski SA, Vogel J. Single-cell RNA-seq: advances and future challenges. Nucleic Acids Res 2014; 42:8845-60. [PMID: 25053837 PMCID: PMC4132710 DOI: 10.1093/nar/gku555] [Citation(s) in RCA: 492] [Impact Index Per Article: 49.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Phenotypically identical cells can dramatically vary with respect to behavior during their lifespan and this variation is reflected in their molecular composition such as the transcriptomic landscape. Single-cell transcriptomics using next-generation transcript sequencing (RNA-seq) is now emerging as a powerful tool to profile cell-to-cell variability on a genomic scale. Its application has already greatly impacted our conceptual understanding of diverse biological processes with broad implications for both basic and clinical research. Different single-cell RNA-seq protocols have been introduced and are reviewed here—each one with its own strengths and current limitations. We further provide an overview of the biological questions single-cell RNA-seq has been used to address, the major findings obtained from such studies, and current challenges and expected future developments in this booming field.
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Affiliation(s)
- Antoine-Emmanuel Saliba
- Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
| | - Alexander J Westermann
- Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
| | - Stanislaw A Gorski
- Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
| | - Jörg Vogel
- Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
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28
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Kłossowicz M, Marek-Bukowiec K, Arbulo-Echevarria MM, Ścirka B, Majkowski M, Sikorski AF, Aguado E, Miazek A. Identification of functional, short-lived isoform of linker for activation of T cells (LAT). Genes Immun 2014; 15:449-56. [PMID: 25008862 DOI: 10.1038/gene.2014.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 05/04/2014] [Accepted: 05/23/2014] [Indexed: 12/13/2022]
Abstract
Linker for activation of T cells (LAT) is a transmembrane adaptor protein playing a key role in the development, activation and maintenance of peripheral homeostasis of T cells. In this study we identified a functional isoform of LAT. It originates from an intron 6 retention event generating an in-frame splice variant of LAT mRNA denoted as LATi6. Comparison of LATi6 expression in peripheral blood leukocytes of human and several other mammalian species revealed that it varied from being virtually absent in the mouse to being predominant in the cow. Analysis of LAT isoform frequency expressed from minigene splicing reporters carrying loss- or gain-of-function point mutations within intronic polyguanine sequences showed that these elements are critical for controlling the intron 6 removal. The protein product of LATi6 isoform (LATi6) ectopically expressed in LAT-deficient JCam 2.5 cell line localized correctly to subcellular compartments and supported T-cell receptor signaling but differed from the canonical LAT protein by displaying a shorter half-life and mediating an increased interleukin-2 secretion upon prolonged CD3/CD28 crosslinking. Altogether, our data suggest that the appearance of LATi6 isoform is an evolutionary innovation that may contribute to a more efficient proofreading control of effector T-cell response.
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Affiliation(s)
- M Kłossowicz
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - K Marek-Bukowiec
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - M M Arbulo-Echevarria
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cadiz and Puerto Real University Hospital Research Unit, School of Medicine, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cadiz, Spain
| | - B Ścirka
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - M Majkowski
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wroclaw, Poland
| | - A F Sikorski
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wroclaw, Poland
| | - E Aguado
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cadiz and Puerto Real University Hospital Research Unit, School of Medicine, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cadiz, Spain
| | - A Miazek
- 1] Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland [2] Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
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29
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Buckley PT, Khaladkar M, Kim J, Eberwine J. Cytoplasmic intron retention, function, splicing, and the sentinel RNA hypothesis. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 5:223-30. [PMID: 24190870 DOI: 10.1002/wrna.1203] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 09/11/2013] [Accepted: 10/04/2013] [Indexed: 01/07/2023]
Abstract
Cytoplasmic splicing represents a newly emerging level of transcriptional regulation adding to the molecular diversity of mammalian cells. As examples of this noncanonical form of transcript processing are discovered, the evidence of its importance to normal cellular function grows. Work from a number of groups using a variety of cell types is steadily identifying a large number of transcripts (and soon to be even larger as genome-wide analyses of retained introns across a number of cellular phenotypes are currently underway) that undergo some level of regulated endogenous extranuclear splicing as part of their normal biosynthetic pathway. Here, we review the existing data covering cytoplasmic retained intron sequences and suggest that such sequences may be a component of 'sentinel RNA' that serves to generate transcript variants within the cytoplasm as well as a source for RNA-based secondary messages.
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Affiliation(s)
- Peter T Buckley
- Department of Pharmacology, Perelman School of Medicine and the School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
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