1
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Recinos Y, Ustianenko D, Yeh YT, Wang X, Jacko M, Yesantharao LV, Wu Q, Zhang C. CRISPR-dCas13d-based deep screening of proximal and distal splicing-regulatory elements. Nat Commun 2024; 15:3839. [PMID: 38714659 PMCID: PMC11076525 DOI: 10.1038/s41467-024-47140-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 03/16/2024] [Indexed: 05/10/2024] Open
Abstract
Pre-mRNA splicing, a key process in gene expression, can be therapeutically modulated using various drug modalities, including antisense oligonucleotides (ASOs). However, determining promising targets is hampered by the challenge of systematically mapping splicing-regulatory elements (SREs) in their native sequence context. Here, we use the catalytically inactive CRISPR-RfxCas13d RNA-targeting system (dCas13d/gRNA) as a programmable platform to bind SREs and modulate splicing by competing against endogenous splicing factors. SpliceRUSH, a high-throughput screening method, was developed to map SREs in any gene of interest using a lentivirus gRNA library that tiles the genetic region, including distal intronic sequences. When applied to SMN2, a therapeutic target for spinal muscular atrophy, SpliceRUSH robustly identifies not only known SREs but also a previously unknown distal intronic SRE, which can be targeted to alter exon 7 splicing using either dCas13d/gRNA or ASOs. This technology enables a deeper understanding of splicing regulation with applications for RNA-based drug discovery.
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Affiliation(s)
- Yocelyn Recinos
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Dmytro Ustianenko
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
- Flagship Pioneering, Cambridge, MA, 02142, USA
| | - Yow-Tyng Yeh
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Xiaojian Wang
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Martin Jacko
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
- Aperture Therapeutics, Inc., San Carlos, CA, 94070, USA
| | - Lekha V Yesantharao
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
- Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Qiyang Wu
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Chaolin Zhang
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA.
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA.
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2
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Recinos Y, Ustianenko D, Yeh YT, Wang X, Jacko M, Yesantharao LV, Wu Q, Zhang C. Deep screening of proximal and distal splicing-regulatory elements in a native sequence context. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554109. [PMID: 37662340 PMCID: PMC10473672 DOI: 10.1101/2023.08.21.554109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Pre-mRNA splicing, a key process in gene expression, can be therapeutically modulated using various drug modalities, including antisense oligonucleotides (ASOs). However, determining promising targets is impeded by the challenge of systematically mapping splicing-regulatory elements (SREs) in their native sequence context. Here, we use the catalytically dead CRISPR-RfxCas13d RNA-targeting system (dCas13d/gRNA) as a programmable platform to bind SREs and modulate splicing by competing against endogenous splicing factors. SpliceRUSH, a high-throughput screening method, was developed to map SREs in any gene of interest using a lentivirus gRNA library that tiles the genetic region, including distal intronic sequences. When applied to SMN2, a therapeutic target for spinal muscular atrophy, SpliceRUSH robustly identified not only known SREs, but also a novel distal intronic splicing enhancer, which can be targeted to alter exon 7 splicing using either dCas13d/gRNA or ASOs. This technology enables a deeper understanding of splicing regulation with applications for RNA-based drug discovery.
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Affiliation(s)
- Yocelyn Recinos
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Dmytro Ustianenko
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Present address: Flagship Pioneering, Cambridge, MA 02142, USA
| | - Yow-Tyng Yeh
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Xiaojian Wang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Martin Jacko
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Present address: Aperture Therapeutics, Inc., San Carlos, CA 94070, USA
| | - Lekha V. Yesantharao
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Present address: Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Qiyang Wu
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Chaolin Zhang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
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3
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Rogalska ME, Vivori C, Valcárcel J. Regulation of pre-mRNA splicing: roles in physiology and disease, and therapeutic prospects. Nat Rev Genet 2023; 24:251-269. [PMID: 36526860 DOI: 10.1038/s41576-022-00556-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2022] [Indexed: 12/23/2022]
Abstract
The removal of introns from mRNA precursors and its regulation by alternative splicing are key for eukaryotic gene expression and cellular function, as evidenced by the numerous pathologies induced or modified by splicing alterations. Major recent advances have been made in understanding the structures and functions of the splicing machinery, in the description and classification of physiological and pathological isoforms and in the development of the first therapies for genetic diseases based on modulation of splicing. Here, we review this progress and discuss important remaining challenges, including predicting splice sites from genomic sequences, understanding the variety of molecular mechanisms and logic of splicing regulation, and harnessing this knowledge for probing gene function and disease aetiology and for the design of novel therapeutic approaches.
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Affiliation(s)
- Malgorzata Ewa Rogalska
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Claudia Vivori
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- The Francis Crick Institute, London, UK
| | - Juan Valcárcel
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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4
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Qiu J, Qu R, Lin M, Xu J, Zhu Q, Zhang Z, Sun J. Position-dependent effects of hnRNP A1/A2 in SMN1/2 exon7 splicing. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - GENE REGULATORY MECHANISMS 2022; 1865:194875. [PMID: 36208849 DOI: 10.1016/j.bbagrm.2022.194875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/08/2022] [Accepted: 09/28/2022] [Indexed: 11/07/2022]
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5
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Cortés-López M, Schulz L, Enculescu M, Paret C, Spiekermann B, Quesnel-Vallières M, Torres-Diz M, Unic S, Busch A, Orekhova A, Kuban M, Mesitov M, Mulorz MM, Shraim R, Kielisch F, Faber J, Barash Y, Thomas-Tikhonenko A, Zarnack K, Legewie S, König J. High-throughput mutagenesis identifies mutations and RNA-binding proteins controlling CD19 splicing and CART-19 therapy resistance. Nat Commun 2022; 13:5570. [PMID: 36138008 PMCID: PMC9500061 DOI: 10.1038/s41467-022-31818-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 07/05/2022] [Indexed: 11/29/2022] Open
Abstract
Following CART-19 immunotherapy for B-cell acute lymphoblastic leukaemia (B-ALL), many patients relapse due to loss of the cognate CD19 epitope. Since epitope loss can be caused by aberrant CD19 exon 2 processing, we herein investigate the regulatory code that controls CD19 splicing. We combine high-throughput mutagenesis with mathematical modelling to quantitatively disentangle the effects of all mutations in the region comprising CD19 exons 1-3. Thereupon, we identify ~200 single point mutations that alter CD19 splicing and thus could predispose B-ALL patients to developing CART-19 resistance. Furthermore, we report almost 100 previously unknown splice isoforms that emerge from cryptic splice sites and likely encode non-functional CD19 proteins. We further identify cis-regulatory elements and trans-acting RNA-binding proteins that control CD19 splicing (e.g., PTBP1 and SF3B4) and validate that loss of these factors leads to pervasive CD19 mis-splicing. Our dataset represents a comprehensive resource for identifying predictive biomarkers for CART-19 therapy. Multiple alternative splicing events in CD19 mRNA have been associated with resistance/relapse to CD19 CAR-T therapy in patients with B cell malignancies. Here, by combining patient data and a high-throughput mutagenesis screen, the authors identify single point mutations and RNA-binding proteins that can control CD19 splicing and be associated with CD19 CAR-T therapy resistance.
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Affiliation(s)
| | - Laura Schulz
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Mihaela Enculescu
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Claudia Paret
- Department of Pediatric Hematology/Oncology, Center for Pediatric and Adolescent Medicine, University Medical Center of the Johannes Gutenberg University Mainz, 55131, Mainz, Germany.,University Cancer Center (UCT), University Medical Center of the Johannes Gutenberg University Mainz, 55131, Mainz, Germany.,German Cancer Consortium (DKTK), site Frankfurt/Mainz, Germany, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Bea Spiekermann
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Mathieu Quesnel-Vallières
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA.,Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Manuel Torres-Diz
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Sebastian Unic
- Department of Systems Biology, Institute for Biomedical Genetics (IBMG), University of Stuttgart, Allmandring 30E, 70569, Stuttgart, Germany
| | - Anke Busch
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Anna Orekhova
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Monika Kuban
- Department of Systems Biology, Institute for Biomedical Genetics (IBMG), University of Stuttgart, Allmandring 30E, 70569, Stuttgart, Germany
| | - Mikhail Mesitov
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Miriam M Mulorz
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Rawan Shraim
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.,Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Fridolin Kielisch
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Jörg Faber
- Department of Pediatric Hematology/Oncology, Center for Pediatric and Adolescent Medicine, University Medical Center of the Johannes Gutenberg University Mainz, 55131, Mainz, Germany.,University Cancer Center (UCT), University Medical Center of the Johannes Gutenberg University Mainz, 55131, Mainz, Germany.,German Cancer Consortium (DKTK), site Frankfurt/Mainz, Germany, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Yoseph Barash
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Andrei Thomas-Tikhonenko
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.,Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS), Max-von-Laue-Str. 15, 60438, Frankfurt, Germany. .,Faculty Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt, Germany.
| | - Stefan Legewie
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany. .,Department of Systems Biology, Institute for Biomedical Genetics (IBMG), University of Stuttgart, Allmandring 30E, 70569, Stuttgart, Germany. .,Stuttgart Research Center for Systems Biology (SRCSB), University of Stuttgart, Stuttgart, Germany.
| | - Julian König
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
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6
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Jones AN, Graß C, Meininger I, Geerlof A, Klostermann M, Zarnack K, Krappmann D, Sattler M. Modulation of pre-mRNA structure by hnRNP proteins regulates alternative splicing of MALT1. SCIENCE ADVANCES 2022; 8:eabp9153. [PMID: 35921415 PMCID: PMC9348792 DOI: 10.1126/sciadv.abp9153] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Alternative splicing plays key roles for cell type-specific regulation of protein function. It is controlled by cis-regulatory RNA elements that are recognized by RNA binding proteins (RBPs). The MALT1 paracaspase is a key factor of signaling pathways that mediate innate and adaptive immune responses. Alternative splicing of MALT1 is critical for controlling optimal T cell activation. We demonstrate that MALT1 splicing depends on RNA structural elements that sequester the splice sites of the alternatively spliced exon7. The RBPs hnRNP U and hnRNP L bind competitively to stem-loop RNA structures that involve the 5' and 3' splice sites flanking exon7. While hnRNP U stabilizes RNA stem-loop conformations that maintain exon7 skipping, hnRNP L disrupts these RNA elements to facilitate recruitment of the essential splicing factor U2AF2, thereby promoting exon7 inclusion. Our data represent a paradigm for the control of splice site selection by differential RBP binding and modulation of pre-mRNA structure.
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Affiliation(s)
- Alisha N. Jones
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
| | - Carina Graß
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Isabel Meininger
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Arie Geerlof
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Melina Klostermann
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Daniel Krappmann
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Corresponding author. (D.K.); (M.S.)
| | - Michael Sattler
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
- Corresponding author. (D.K.); (M.S.)
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7
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Conboy JG. A Deep Exon Cryptic Splice Site Promotes Aberrant Intron Retention in a Von Willebrand Disease Patient. Int J Mol Sci 2021; 22:13248. [PMID: 34948044 PMCID: PMC8706089 DOI: 10.3390/ijms222413248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 12/13/2022] Open
Abstract
A translationally silent single nucleotide mutation in exon 44 (E44) of the von Willebrand factor (VWF) gene is associated with inefficient removal of intron 44 in a von Willebrand disease (VWD) patient. This intron retention (IR) event was previously attributed to reordered E44 secondary structure that sequesters the normal splice donor site. We propose an alternative mechanism: the mutation introduces a cryptic splice donor site that interferes with the function of the annotated site to favor IR. We evaluated both models using minigene splicing reporters engineered to vary in secondary structure and/or cryptic splice site content. Analysis of splicing efficiency in transfected K562 cells suggested that the mutation-generated cryptic splice site in E44 was sufficient to induce substantial IR. Mutations predicted to vary secondary structure at the annotated site also had modest effects on IR and shifted the balance of residual splicing between the cryptic site and annotated site, supporting competition among the sites. Further studies demonstrated that introduction of cryptic splice donor motifs at other positions in E44 did not promote IR, indicating that interference with the annotated site is context dependent. We conclude that mutant deep exon splice sites can interfere with proper splicing by inducing IR.
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Affiliation(s)
- John G Conboy
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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8
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Saha K, Fernandez MM, Biswas T, Joseph S, Ghosh G. Discovery of a pre-mRNA structural scaffold as a contributor to the mammalian splicing code. Nucleic Acids Res 2021; 49:7103-7121. [PMID: 34161584 PMCID: PMC8266590 DOI: 10.1093/nar/gkab533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
The specific recognition of splice signals at or near exon-intron junctions is not explained by their weak conservation and instead is postulated to require a multitude of features embedded in the pre-mRNA strand. We explored the possibility of 3D structural scaffold of AdML-a model pre-mRNA substrate-guiding early spliceosomal components to the splice signal sequences. We find that mutations in the non-cognate splice signal sequences impede recruitment of early spliceosomal components due to disruption of the global structure of the pre-mRNA. We further find that the pre-mRNA segments potentially interacting with the early spliceosomal component U1 snRNP are distributed across the intron, that there is a spatial proximity of 5' and 3' splice sites within the pre-mRNA scaffold, and that an interplay exists between the structural scaffold and splicing regulatory elements in recruiting early spliceosomal components. These results suggest that early spliceosomal components can recognize a 3D structural scaffold beyond the short splice signal sequences, and that in our model pre-mRNA, this scaffold is formed across the intron involving the major splice signals. This provides a conceptual basis to analyze the contribution of recognizable 3D structural scaffolds to the splicing code across the mammalian transcriptome.
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Affiliation(s)
- Kaushik Saha
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0375, USA
| | - Mike Minh Fernandez
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0375, USA
| | - Tapan Biswas
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0375, USA
| | - Simpson Joseph
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0375, USA
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0375, USA
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9
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Choi N, Liu Y, Oh J, Ha J, Ghigna C, Zheng X, Shen H. Relative strength of 5’ splice-site strength defines functions of SRSF2 and SRSF6 in alternative splicing of Bcl-x pre-mRNA. BMB Rep 2021. [PMID: 33050987 PMCID: PMC8016662 DOI: 10.5483/bmbrep.2021.54.3.170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Bcl-x, a member of the Bcl-2 family, plays a key role in apoptosis. Alternative splicing of Bcl-x pre-mRNA through alternative 5’ splice-site selection produces an anti-apoptotic mRNA isoform that includes exon 2b and a pro-apoptotic Bcl-x mRNA isoform that excludes exon 2b. Here we used Bcl-x minigene and identified SRSF2 and SRSF6 as two regulatory factors of 5’ splice-site selection of Bcl-x pre-mRNA. We selected binding clusters closer to 5’ splice-sites from multiple potential binding sites of SRSF2 and SRSF6 to perform loss of functions analysis through site-directed mutagenesis. Our results demonstrated that these mutations did not abolish regulatory functions of SRSF2 or SRSF6, indicating that a single binding motif or a cluster was not a functional target of these proteins in Bcl-x pre-mRNA splicing. Random deletion mutagenesis did not disrupt the role of SRSF2 and SRSF6. Importantly, mutagenesis of 5’ splice-site to a conserved or a weaker score demonstrated that the weaker strength of the target 5’ splice-site or higher strength of the other 5’ splice-site strength limited the role of SRSF2 and SRSF6 in 5’ splice-site activation.
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Affiliation(s)
- Namjeong Choi
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Yongchao Liu
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jagyeong Oh
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jiyeon Ha
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Claudia Ghigna
- Institute of Molecular Genetics “Luigi Luca Cavalli-Sforza”, National Research Council, Pavia 27100, Italy
| | - Xuexiu Zheng
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Haihong Shen
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
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10
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Abstract
High-throughput sequencing-based methods and their applications in the study of transcriptomes have revolutionized our understanding of alternative splicing. Networks of functionally coordinated and biologically important alternative splicing events continue to be discovered in an ever-increasing diversity of cell types in the context of physiologically normal and disease states. These studies have been complemented by efforts directed at defining sequence codes governing splicing and their cognate trans-acting factors, which have illuminated important combinatorial principles of regulation. Additional studies have revealed critical roles of position-dependent, multivalent protein-RNA interactions that direct splicing outcomes. Investigations of evolutionary changes in RNA binding proteins, splice variants, and associated cis elements have further shed light on the emergence, mechanisms, and functions of splicing networks. Progress in these areas has emphasized the need for a coordinated, community-based effort to systematically address the functions of individual splice variants associated with normal and disease biology.
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11
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Shilo A, Tosto FA, Rausch JW, Le Grice SFJ, Misteli T. Interplay of primary sequence, position and secondary RNA structure determines alternative splicing of LMNA in a pre-mature aging syndrome. Nucleic Acids Res 2019; 47:5922-5935. [PMID: 31006814 DOI: 10.1093/nar/gkz259] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/25/2019] [Accepted: 04/01/2019] [Indexed: 11/14/2022] Open
Abstract
Aberrant splicing in exon 11 of the LMNA gene causes the premature aging disorder Hutchinson-Gilford Progeria Syndrome. A de novo C1824T mutation activates an internal alternative 5' splice site, resulting in formation of the disease-causing progerin protein. The underlying mechanism for this 5' splice site selection is unknown. Here, we have applied a combination of targeted mutational analysis in a cell-based system and structural mapping by SHAPE-MaP to comprehensively probe the contributions of primary sequence, secondary RNA structure and linear splice site position in determining in vivo mechanisms of splice site choice in LMNA. While splice site choice is in part defined by sequence complementarity to U1 snRNA, we identify RNA secondary structural elements near the alternative 5' splice sites and show that splice site choice is significantly influenced by the structural context of the available splice sites. Furthermore, relative positioning of the competing sites within the primary sequence of the pre-mRNA is a predictor of 5' splice site usage, with the distal position favored over the proximal, regardless of sequence composition. Together, these results demonstrate that 5' splice site selection in LMNA is determined by an intricate interplay among RNA sequence, secondary structure and splice site position.
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Affiliation(s)
- Asaf Shilo
- Cell Biology of Genomes, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Frances Anne Tosto
- Cell Biology of Genomes, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Jason W Rausch
- Basic Research Laboratory, National Cancer Institute, NIH, Frederick, MD 21702, USA
| | - Stuart F J Le Grice
- Basic Research Laboratory, National Cancer Institute, NIH, Frederick, MD 21702, USA
| | - Tom Misteli
- Cell Biology of Genomes, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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12
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Wheway G, Lord J, Baralle D. Splicing in the pathogenesis, diagnosis and treatment of ciliopathies. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194433. [PMID: 31698098 DOI: 10.1016/j.bbagrm.2019.194433] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/12/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Abstract
Primary cilia are essential signalling organelles found on the apical surface of epithelial cells, where they coordinate chemosensation, mechanosensation and light sensation. Motile cilia play a central role in establishing fluid flow in the respiratory tract, reproductive tract, brain ventricles and ear. Genetic defects affecting the structure or function of cilia can lead to a broad range of developmental and degenerative diseases known as ciliopathies. Splicing contributes to the pathogenesis, diagnosis and treatment of ciliopathies. Tissue-specific alternative splicing contributes to the tissue-specific manifestation of ciliopathy phenotypes, for example the retinal-specific effects of some genetic defects, due to specific transcript expression in the highly specialised ciliated cells of the retina, the photoreceptor cells. Ciliopathies can arise both as a result of genetic variants in spliceosomal proteins, or as a result of variants affecting splicing of specific cilia genes. Here we discuss the opportunities and challenges in diagnosing ciliopathies using RNA sequence analysis and the potential for treating ciliopathies in a relatively mutation-neutral way by targeting splicing. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Gabrielle Wheway
- Faculty of Medicine, University of Southampton, Human Development and Health, United Kingdom of Great Britain and Northern Ireland; University Hospital Southampton NHS Foundation Trust, United Kingdom of Great Britain and Northern Ireland
| | - Jenny Lord
- Faculty of Medicine, University of Southampton, Human Development and Health, United Kingdom of Great Britain and Northern Ireland; University Hospital Southampton NHS Foundation Trust, United Kingdom of Great Britain and Northern Ireland
| | - Diana Baralle
- Faculty of Medicine, University of Southampton, Human Development and Health, United Kingdom of Great Britain and Northern Ireland; University Hospital Southampton NHS Foundation Trust, United Kingdom of Great Britain and Northern Ireland.
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13
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Xu B, Shi Y, Wu Y, Meng Y, Jin Y. Role of RNA secondary structures in regulating Dscam alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194381. [DOI: 10.1016/j.bbagrm.2019.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/21/2019] [Accepted: 04/22/2019] [Indexed: 12/19/2022]
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14
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Gu J, Xia Z, Luo Y, Jiang X, Qian B, Xie H, Zhu JK, Xiong L, Zhu J, Wang ZY. Spliceosomal protein U1A is involved in alternative splicing and salt stress tolerance in Arabidopsis thaliana. Nucleic Acids Res 2019; 46:1777-1792. [PMID: 29228330 PMCID: PMC5829640 DOI: 10.1093/nar/gkx1229] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/30/2017] [Indexed: 12/14/2022] Open
Abstract
Soil salinity is a significant threat to sustainable agricultural production worldwide. Plants must adjust their developmental and physiological processes to cope with salt stress. Although the capacity for adaptation ultimately depends on the genome, the exceptional versatility in gene regulation provided by the spliceosome-mediated alternative splicing (AS) is essential in these adaptive processes. However, the functions of the spliceosome in plant stress responses are poorly understood. Here, we report the in-depth characterization of a U1 spliceosomal protein, AtU1A, in controlling AS of pre-mRNAs under salt stress and salt stress tolerance in Arabidopsis thaliana. The atu1a mutant was hypersensitive to salt stress and accumulated more reactive oxygen species (ROS) than the wild-type under salt stress. RNA-seq analysis revealed that AtU1A regulates AS of many genes, presumably through modulating recognition of 5′ splice sites. We showed that AtU1A is associated with the pre-mRNA of the ROS detoxification-related gene ACO1 and is necessary for the regulation of ACO1 AS. ACO1 is important for salt tolerance because ectopic expression of ACO1 in the atu1a mutant can partially rescue its salt hypersensitive phenotype. Our findings highlight the critical role of AtU1A as a regulator of pre-mRNA processing and salt tolerance in plants.
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Affiliation(s)
- Jinbao Gu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Zhiqiang Xia
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China
| | - Yuehua Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Xingyu Jiang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Bilian Qian
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA
| | - He Xie
- Tobacco Breeding and Biotechnology Research Center, Yunnan Academy of Tobacco Agricultural Sciences, Kunming 650021, China
| | - Jian-Kang Zhu
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47906, USA.,Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Liming Xiong
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences & Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Jianhua Zhu
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA
| | - Zhen-Yu Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
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15
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Jia R, Ajiro M, Yu L, McCoy P, Zheng ZM. Oncogenic splicing factor SRSF3 regulates ILF3 alternative splicing to promote cancer cell proliferation and transformation. RNA (NEW YORK, N.Y.) 2019; 25:630-644. [PMID: 30796096 PMCID: PMC6467003 DOI: 10.1261/rna.068619.118] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 02/21/2019] [Indexed: 05/28/2023]
Abstract
Alternative RNA splicing is an important focus in molecular and clinical oncology. We report here that SRSF3 regulates alternative RNA splicing of interleukin enhancer binding factor 3 (ILF3) and production of this double-strand RNA-binding protein. An increased coexpression of ILF3 isoforms and SRSF3 was found in various types of cancers. ILF3 isoform-1 and isoform-2 promote cell proliferation and transformation. Tumor cells with reduced SRSF3 expression produce aberrant isoform-5 and -7 of ILF3. By binding to RNA sequence motifs, SRSF3 regulates the production of various ILF3 isoforms by exclusion/inclusion of ILF3 exon 18 or by selection of an alternative 3' splice site within exon 18. ILF3 isoform-5 and isoform-7 suppress tumor cell proliferation and the isoform-7 induces cell apoptosis. Our data indicate that ILF3 isoform-1 and isoform-2 are two critical factors for cell proliferation and transformation. The increased SRSF3 expression in cancer cells plays an important role in maintaining the steady status of ILF3 isoform-1 and isoform-2.
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Affiliation(s)
- Rong Jia
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Ke Laboratory for Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei 430079, China
| | - Masahiko Ajiro
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
| | - Lulu Yu
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
| | - Philip McCoy
- Flow Cytometry Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
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16
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Comparative Analysis of Brain and Fat Body Gene Splicing Patterns in the Honey Bee, Apis mellifera. G3-GENES GENOMES GENETICS 2019; 9:1055-1063. [PMID: 30792192 PMCID: PMC6469410 DOI: 10.1534/g3.118.200857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
RNA-seq has proven to be a powerful tool to unravel various aspects of the transcriptome, especially the quantification of alternative splicing (AS) that leads to isoform diversity. The honey bee (Apis mellifera) is an important model organism for studying the molecular underpinnings of behavioral plasticity and social behavior, and recent RNA-seq studies of honey bees have revealed AS patterns and their regulation by DNA methylation. However, tissue-specific AS patterns have not been fully explored. In this paper, we characterized AS patterns in two different honey bee tissue types, and also explored their conservation and regulation. We used the RNA-seq data from brain and fat body to improve the existing models of honey bee genes and identified tissue-specific AS patterns. We found that AS genes show high conservation between honey bee and Drosophila melanogaster. We also confirmed and extended previous findings of a correlation between gene body DNA methylation and AS patterns, providing further support for the role of DNA methylation in regulating AS. In addition, our analysis suggests distinct functional roles for tissue-specific alternatively spliced genes. Taken together, our work provides new insights into the conservation and dynamics of AS patterns across different tissue types.
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17
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Mao M, Hu Y, Yang Y, Qian Y, Wei H, Fan W, Yang Y, Li X, Wang Z. Modeling and Predicting the Activities of Trans-Acting Splicing Factors with Machine Learning. Cell Syst 2018; 7:510-520.e4. [PMID: 30414922 DOI: 10.1016/j.cels.2018.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 05/10/2018] [Accepted: 09/19/2018] [Indexed: 02/06/2023]
Abstract
Alternative splicing (AS) is generally regulated by trans-splicing factors that specifically bind to cis-elements in pre-mRNAs. The human genome encodes ∼1,500 RNA binding proteins (RBPs) that potentially regulate AS, yet their functions remain largely unknown. To explore their potential activities, we fused the putative functional domains of RBPs to a sequence-specific RNA-binding domain and systemically analyzed how these engineered factors affect splicing. We discovered that ∼80% of low-complexity domains in endogenous RBPs displayed distinct context-dependent activities in regulating splicing, indicating that AS is under more extensive regulation than previously expected. We developed a machine learning approach to classify and predict the activities of RBPs based on their sequence compositions and further validated this model using endogenous RBPs and synthetic polypeptides. These results represent a systematic inspection, modeling, prediction, and validation of how RBP sequences affect their activities in controlling splicing, paving the way for de novo engineering of artificial splicing factors.
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Affiliation(s)
- Miaowei Mao
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China; Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Yue Hu
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yun Yang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yajie Qian
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Huanhuan Wei
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wei Fan
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Yi Yang
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaoling Li
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Zefeng Wang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China.
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18
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Ohe K, Miyajima S, Abe I, Tanaka T, Hamaguchi Y, Harada Y, Horita Y, Beppu Y, Ito F, Yamasaki T, Terai H, Mori M, Murata Y, Tanabe M, Ashida K, Kobayashi K, Enjoji M, Yanase T, Harada N, Utsumi T, Mayeda A. HMGA1a induces alternative splicing of estrogen receptor alpha in MCF-7 human breast cancer cells. J Steroid Biochem Mol Biol 2018; 182:21-26. [PMID: 29678492 DOI: 10.1016/j.jsbmb.2018.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/23/2017] [Accepted: 04/13/2018] [Indexed: 12/11/2022]
Abstract
The high-mobility group A protein 1a (HMGA1a) protein is known as an oncogene whose expression level in cancer tissue correlates with the malignant potential, and known as a component of senescence-related structures connecting it to tumor suppressor networks in fibroblasts. HMGA1 protein binds to DNA, but recent studies have shown it exerts novel functions through RNA-binding. Our previous studies have shown that sequence-specific RNA-binding of HMGA1a induces exon-skipping of Presenilin-2 exon 5 in sporadic Alzheimer disease. Here we show that HMGA1a induced exon-skipping of the estrogen receptor alpha (ERα) gene and increased ERα46 mRNA expression in MCF-7 breast cancer cells. An RNA-decoy of HMGA1a efficiently blocked this event and reduced ERα46 protein expression. Blockage of HMGA1a RNA-binding property consequently induced cell growth through reduced ERα46 expression in MCF-7 cells and increased sensitivity to tamoxifen in the tamoxifen-resistant cell line, MCF-7/TAMR1. Stable expression of an HMGA1a RNA-decoy in MCF-7 cells exhibited decreased ERα46 protein expression and increased estrogen-dependent tumor growth when these cells were implanted in nude mice. These results show HMGA1a is involved in alternative splicing of the ERα gene and related to estrogen-related growth as well as tamoxifen sensitivity in MCF-7 breast cancer cells.
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Affiliation(s)
- Kenji Ohe
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan.
| | - Shinsuke Miyajima
- Department of Breast Surgery, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Ichiro Abe
- Department of Endocrinology and Diabetes Mellitus, Fukuoka University Chikushi Hospital, Chikushino city, 818-8502, Japan
| | - Tomoko Tanaka
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Yuriko Hamaguchi
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Yoshihiro Harada
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Yuta Horita
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Yuki Beppu
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Fumiaki Ito
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Takafumi Yamasaki
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Hiroki Terai
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Masayoshi Mori
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Yusuke Murata
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Makito Tanabe
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Kenji Ashida
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kunihisa Kobayashi
- Department of Endocrinology and Diabetes Mellitus, Fukuoka University Chikushi Hospital, Chikushino city, 818-8502, Japan
| | - Munechika Enjoji
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Toshihiko Yanase
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-180, Japan
| | - Nobuhiro Harada
- Department of Biochemistry, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Toshiaki Utsumi
- Department of Breast Surgery, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science (ICMS), Fujita Health University, Aichi, Toyoake, 470-1192, Japan
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19
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Dvinge H. Regulation of alternative
mRNA
splicing: old players and new perspectives. FEBS Lett 2018; 592:2987-3006. [DOI: 10.1002/1873-3468.13119] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/23/2018] [Accepted: 05/29/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Heidi Dvinge
- Department of Biomolecular Chemistry School of Medicine and Public Health University of Wisconsin‐Madison WI USA
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20
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Ohe K, Miyajima S, Tanaka T, Hamaguchi Y, Harada Y, Horita Y, Beppu Y, Ito F, Yamasaki T, Terai H, Mori M, Murata Y, Tanabe M, Abe I, Ashida K, Kobayashi K, Enjoji M, Nomiyama T, Yanase T, Harada N, Utsumi T, Mayeda A. HMGA1a Induces Alternative Splicing of the Estrogen Receptor-α lpha Gene by Trapping U1 snRNP to an Upstream Pseudo-5' Splice Site. Front Mol Biosci 2018; 5:52. [PMID: 29938207 PMCID: PMC6002489 DOI: 10.3389/fmolb.2018.00052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/22/2018] [Indexed: 12/31/2022] Open
Abstract
Objectives: The high-mobility group A protein 1a (HMGA1a) protein is known as a transcription factor that binds to DNA, but recent studies have shown it exerts novel functions through RNA-binding. We were prompted to decipher the mechanism of HMGA1a-induced alternative splicing of the estrogen receptor alpha (ERα) that we recently reported would alter tamoxifen sensitivity in MCF-7 TAMR1 cells. Methods: Endogenous expression of full length ERα66 and its isoform ERα46 were evaluated in MCF-7 breast cancer cells by transient expression of HMGA1a and an RNA decoy (2′-O-methylated RNA of the HMGA1a RNA-binding site) that binds to HMGA1a. RNA-binding of HMGA1a was checked by RNA-EMSA. In vitro splicing assay was performed to check the direct involvement of HMGA1a in splicing regulation. RNA-EMSA assay in the presence of purified U1 snRNP was performed with psoralen UV crosslinking to check complex formation of HMGA1a-U1 snRNP at the upstream pseudo-5′ splice site of exon 1. Results: HMGA1a induced exon skipping of a shortened exon 1 of ERα in in vitro splicing assays that was blocked by the HMGA1a RNA decoy and sequence-specific RNA-binding was confirmed by RNA-EMSA. RNA-EMSA combined with psoralen UV crosslinking showed that HMGA1a trapped purified U1 snRNP at the upstream pseudo-5′ splice site. Conclusions: Regulation of ERα alternative splicing by an HMGA1a-trapped U1 snRNP complex at the upstream 5′ splice site of exon 1 offers novel insight on 5′ splice site regulation by U1 snRNP as well as a promising target in breast cancer therapy where alternative splicing of ERα is involved.
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Affiliation(s)
- Kenji Ohe
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Shinsuke Miyajima
- Department of Breast Surgery, Fujita Health University, Toyoake, Japan
| | - Tomoko Tanaka
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Yuriko Hamaguchi
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Yoshihiro Harada
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Yuta Horita
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Yuki Beppu
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Fumiaki Ito
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Takafumi Yamasaki
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Hiroki Terai
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Masayoshi Mori
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Yusuke Murata
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Makito Tanabe
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Ichiro Abe
- Department of Endocrinology and Diabetes Mellitus, Fukuoka University Chikushi Hospital, Chikushino, Japan
| | - Kenji Ashida
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kunihisa Kobayashi
- Department of Endocrinology and Diabetes Mellitus, Fukuoka University Chikushi Hospital, Chikushino, Japan
| | - Munechika Enjoji
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Takashi Nomiyama
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Toshihiko Yanase
- Department of Endocrinology and Diabetes Mellitus, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Nobuhiro Harada
- Department of Biochemistry, Fujita Health University, Toyoake, Japan
| | - Toshiaki Utsumi
- Department of Breast Surgery, Fujita Health University, Toyoake, Japan
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Japan
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21
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Ke S, Anquetil V, Zamalloa JR, Maity A, Yang A, Arias MA, Kalachikov S, Russo JJ, Ju J, Chasin LA. Saturation mutagenesis reveals manifold determinants of exon definition. Genome Res 2017; 28:11-24. [PMID: 29242188 PMCID: PMC5749175 DOI: 10.1101/gr.219683.116] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 11/27/2017] [Indexed: 11/24/2022]
Abstract
To illuminate the extent and roles of exonic sequences in the splicing of human RNA transcripts, we conducted saturation mutagenesis of a 51-nt internal exon in a three-exon minigene. All possible single and tandem dinucleotide substitutions were surveyed. Using high-throughput genetics, 5560 minigene molecules were assayed for splicing in human HEK293 cells. Up to 70% of mutations produced substantial (greater than twofold) phenotypes of either increased or decreased splicing. Of all predicted secondary structural elements, only a single 15-nt stem–loop showed a strong correlation with splicing, acting negatively. The in vitro formation of exon-protein complexes between the mutant molecules and proteins associated with spliceosome formation (U2AF35, U2AF65, U1A, and U1-70K) correlated with splicing efficiencies, suggesting exon definition as the step affected by most mutations. The measured relative binding affinities of dozens of human RNA binding protein domains as reported in the CISBP-RNA database were found to correlate either positively or negatively with splicing efficiency, more than could fit on the 51-nt test exon simultaneously. The large number of these functional protein binding correlations point to a dynamic and heterogeneous population of pre-mRNA molecules, each responding to a particular collection of binding proteins.
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Affiliation(s)
- Shengdong Ke
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Vincent Anquetil
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Jorge Rojas Zamalloa
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Alisha Maity
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Anthony Yang
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Mauricio A Arias
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Sergey Kalachikov
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
| | - James J Russo
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
| | - Jingyue Ju
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
| | - Lawrence A Chasin
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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22
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Yeh CS, Chang SL, Chen JH, Wang HK, Chou YC, Wang CH, Huang SH, Larson A, Pleiss JA, Chang WH, Chang TH. The conserved AU dinucleotide at the 5' end of nascent U1 snRNA is optimized for the interaction with nuclear cap-binding-complex. Nucleic Acids Res 2017; 45:9679-9693. [PMID: 28934473 PMCID: PMC5766165 DOI: 10.1093/nar/gkx608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/05/2017] [Indexed: 11/13/2022] Open
Abstract
Splicing is initiated by a productive interaction between the pre-mRNA and the U1 snRNP, in which a short RNA duplex is established between the 5' splice site of a pre-mRNA and the 5' end of the U1 snRNA. A long-standing puzzle has been why the AU dincucleotide at the 5'-end of the U1 snRNA is highly conserved, despite the absence of an apparent role in the formation of the duplex. To explore this conundrum, we varied this AU dinucleotide into all possible permutations and analyzed the resulting molecular consequences. This led to the unexpected findings that the AU dinucleotide dictates the optimal binding of cap-binding complex (CBC) to the 5' end of the nascent U1 snRNA, which ultimately influences the utilization of U1 snRNP in splicing. Our data also provide a structural interpretation as to why the AU dinucleotide is conserved during evolution.
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Affiliation(s)
- Chung-Shu Yeh
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.,Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Jui-Hui Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Hsuan-Kai Wang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan.,Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan
| | - Yue-Chang Chou
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Shih-Hsin Huang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan.,Chemical Biology and Molecular Biophysics program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
| | - Amy Larson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jeffrey A Pleiss
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Wei-Hau Chang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tien-Hsien Chang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.,Genomics Research Center, Academia Sinica, Taipei, Taiwan
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23
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Liu J, Bhadra M, Sinnakannu JR, Yue WL, Tan CW, Rigo F, Ong ST, Roca X. Overcoming imatinib resistance conferred by the BIM deletion polymorphism in chronic myeloid leukemia with splice-switching antisense oligonucleotides. Oncotarget 2017; 8:77567-77585. [PMID: 29100409 PMCID: PMC5652800 DOI: 10.18632/oncotarget.20658] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 07/25/2017] [Indexed: 11/25/2022] Open
Abstract
Many tyrosine kinase-driven cancers, including chronic myeloid leukemia (CML), are characterized by high response rates to specific tyrosine kinase inhibitors (TKIs) like imatinib. In East Asians, primary imatinib resistance is caused by a deletion polymorphism in Intron 2 of the BIM gene, whose product is required for TKI-induced apoptosis. The deletion biases BIM splicing from exon 4 to exon 3, generating splice isoforms lacking the exon 4-encoded pro-apoptotic BH3 domain, which impairs the ability of TKIs to induce apoptosis. We sought to identify splice-switching antisense oligonucleotides (ASOs) that block exon 3 but enhance exon 4 splicing, and thereby resensitize BIM deletion-containing cancers to imatinib. First, we mapped multiple cis-acting splicing elements around BIM exon 3 by minigene mutations, and found an exonic splicing enhancer acting via SRSF1. Second, by a systematic ASO walk, we isolated ASOs that corrected the aberrant BIM splicing. Eight of 67 ASOs increased exon 4 levels in BIM deletion-containing cells, and restored imatinib-induced apoptosis and TKI sensitivity. This proof-of-principle study proves that resistant CML cells by BIM deletion polymorphism can be resensitized to imatinib via splice-switching BIM ASOs. Future optimizations might yield a therapeutic ASO as precision-medicine adjuvant treatment for BIM-polymorphism-associated TKI-resistant CML and other cancers.
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Affiliation(s)
- Jun Liu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Malini Bhadra
- School of Biological Sciences, Nanyang Technological University, Singapore
| | | | - Wan Lin Yue
- School of Biological Sciences, Nanyang Technological University, Singapore.,CN Yang Scholars Programme, Nanyang Technological University, Singapore
| | - Cheryl Weiqi Tan
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | - S Tiong Ong
- Cancer and Stem Cell Biology Signature Research Programme, Duke-NUS Medical School, Singapore.,Department of Haematology, Singapore General Hospital, Singapore.,Department of Medical Oncology, National Cancer Centre Singapore, Singapore.,Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Xavier Roca
- School of Biological Sciences, Nanyang Technological University, Singapore
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24
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SRSF1 suppresses selection of intron-distal 5' splice site of DOK7 intron 4 to generate functional full-length Dok-7 protein. Sci Rep 2017; 7:10446. [PMID: 28874828 PMCID: PMC5585400 DOI: 10.1038/s41598-017-11036-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/18/2017] [Indexed: 01/23/2023] Open
Abstract
Dok-7 is a non-catalytic adaptor protein that facilitates agrin-induced clustering of acetylcholine receptors (AChR) at the neuromuscular junction. Alternative selection of 5′ splice sites (SSs) of DOK7 intron 4 generates canonical and frame-shifted transcripts. We found that the canonical full-length Dok-7 enhanced AChR clustering, whereas the truncated Dok-7 did not. We identified a splicing cis-element close to the 3′ end of exon 4 by block-scanning mutagenesis. RNA affinity purification and mass spectrometry revealed that SRSF1 binds to the cis-element. Knocking down of SRSF1 enhanced selection of the intron-distal 5′ SS of DOK7 intron 4, whereas MS2-mediated artificial tethering of SRSF1 to the identified cis-element suppressed it. Isolation of an early spliceosomal complex revealed that SRSF1 inhibited association of U1 snRNP to the intron-distal 5′ SS, and rather enhanced association of U1 snRNP to the intron-proximal 5′ SS, which led to upregulation of the canonical DOK7 transcript. Integrated global analysis of CLIP-seq and RNA-seq also indicated that binding of SRSF1 immediately upstream to two competing 5′ SSs suppresses selection of the intron-distal 5′ SS in hundreds of human genes. We demonstrate that SRSF1 critically regulates alternative selection of adjacently placed 5′ SSs by modulating binding of U1 snRNP.
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25
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Liu W, Li X, Liao S, Dou K, Zhang Y. Activation of the intronic cryptic 5' splice site depends on its distance to the upstream cassette exon. Gene 2017; 619:30-36. [PMID: 28322992 DOI: 10.1016/j.gene.2017.03.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/13/2017] [Accepted: 03/17/2017] [Indexed: 11/30/2022]
Abstract
Splice site selection is a key step that determines the mRNA isoforms generated from a single transcript. The large diversity in splice site sequences emphasizes the plasticity of splice site recognition and selection. In this report, a cell-based reporter system using a SMN1/2 cassette exon was applied to study the roles governing the activation of a cryptic 5'SS from the intron 4 of the CT/CGRP gene. We found that the cryptic site was activated when placed within 124nt downstream the cassette exon, and the level of activation was negatively correlated with its distance from the exon. In addition, activation was not affected by PTB but was eliminated by an insertion extending the exon length. Activated cryptic 5'SSs in intron or exon could override the original alternative 5'SS, obeying the U1 base-pairing rule. These results suggest that the exon length itself could represent a factor in determining the splice site selection.
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Affiliation(s)
- Wei Liu
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Xia Li
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Shengjie Liao
- Center for Genome Analysis, ABLife Inc., Optics Valley International Biomedical Park, Building 9-4, East Lake High-Tech Development Zone, 388 Gaoxin 2nd Road, Wuhan, Hubei 430075, China; Laboratory for Genome Regulation and Human Heath, ABLife Inc., Optics Valley International Biomedical Park, Building 9-4, East Lake High-Tech Development Zone, 388 Gaoxin 2nd Road, Wuhan, Hubei 430075, China
| | - Kefeng Dou
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, China.
| | - Yi Zhang
- Center for Genome Analysis, ABLife Inc., Optics Valley International Biomedical Park, Building 9-4, East Lake High-Tech Development Zone, 388 Gaoxin 2nd Road, Wuhan, Hubei 430075, China; Laboratory for Genome Regulation and Human Heath, ABLife Inc., Optics Valley International Biomedical Park, Building 9-4, East Lake High-Tech Development Zone, 388 Gaoxin 2nd Road, Wuhan, Hubei 430075, China.
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26
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Deep intronic mutations and human disease. Hum Genet 2017; 136:1093-1111. [DOI: 10.1007/s00439-017-1809-4] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/05/2017] [Indexed: 12/22/2022]
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27
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Deka B, Singh KK. Multifaceted Regulation of Gene Expression by the Apoptosis- and Splicing-Associated Protein Complex and Its Components. Int J Biol Sci 2017; 13:545-560. [PMID: 28539829 PMCID: PMC5441173 DOI: 10.7150/ijbs.18649] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/24/2017] [Indexed: 11/24/2022] Open
Abstract
The differential deposition of RNA-binding proteins (RBPs) on pre-mRNA mediates the processes of gene expression. One of the complexes containing RBPs that play a crucial part in RNA metabolism is the apoptosis-and splicing-associated protein (ASAP) complex. In this review, we present a summary of the structure of ASAP complex and its localization. Also, we discuss the findings by different groups on various functions of the subunits of the ASAP complex in RNA metabolism. The subunits of the ASAP complex are RNPS1, Acinus and SAP18. Originally, the ASAP complex was thought to link RNA processing with apoptosis. Further studies have shown the role of these components in RNA metabolism of cells, including transcription, splicing, translation and nonsense-mediated mRNA decay (NMD). In transcription, RNPS1 is involved in preventing the formation of R-loop, while Acinus and SAP18 suppress transcription with the help of histone deacetylase. On the one hand, individual components of the ASAP complex, namely RNPS1 and Acinus act as splicing activators, whereas on the other hand, in-vitro assay shows that the ASAP complex behaves as splicing repressor. In addition, the individual members of the ASAP complex associates with the exon junction complex (EJC) to play roles in splicing and translation. RNPS1 increases the translation efficiency by participating in the 3'end processing and polysome association of mRNAs. Similarly, during NMD RNPS1 aids in the recruitment of decay factors by interacting with EJC.
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Affiliation(s)
| | - Kusum Kumari Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India
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28
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Loh TJ, Choi N, Moon H, Jang HN, Liu Y, Zhou J, Zheng X, Shen H. Suppression of 5' splice-sites through multiple exonic motifs by hnRNP L. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:363-373. [PMID: 28119102 DOI: 10.1016/j.bbagrm.2017.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/20/2017] [Accepted: 01/20/2017] [Indexed: 10/20/2022]
Abstract
Selection of 5' splice-sites (5'SS) in alternative splicing plays an important role in gene regulation. Although regulatory mechanisms of heterogeneous nuclear ribonucleoprotein L (hnRNP L), a well-known splicing regulatory protein, have been studied in a substantial level, its role in 5'SS selection is not thoroughly defined. By using a KLF6 pre-mRNA alternative splicing model, we demonstrate in this report that hnRNP L inhibits proximal 5'SS but promotes two consecutive distal 5'SS splicing, antagonizing SRSF1 roles in KLF6 pre-mRNA splicing. In addition, three consecutive CA-rich sequences in a CA cassette immediately upstream of the proximal 5'SS are all required for hnRNP L functions. Importantly, the CA-cassette locations on the proximal exon do not affect hnRNP L roles. We further show that the proximal 5'SS but not the two distal 5'SSs are essential for hnRNP L activities. Notably, in a Bcl-x pre-mRNA model that contains two alternative 5'SS but includes CA-rich elements at distal exon, we demonstrate that hnRNP L also suppresses nearby 5'SS activation. Taken together, we conclude that hnRNP L suppresses 5'SS selection through multiple exonic motifs.
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Affiliation(s)
- Tiing Jen Loh
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
| | - Namjeong Choi
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
| | - Heegyum Moon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
| | - Ha Na Jang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
| | - Yongchao Liu
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
| | - Jianhua Zhou
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
| | - Xuexiu Zheng
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
| | - Haihong Shen
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
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29
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30
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Towards understanding pre-mRNA splicing mechanisms and the role of SR proteins. Gene 2016; 587:107-19. [PMID: 27154819 DOI: 10.1016/j.gene.2016.04.057] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 04/30/2016] [Indexed: 01/04/2023]
Abstract
Alternative pre-mRNA splicing provides a source of vast protein diversity by removing non-coding sequences (introns) and accurately linking different exonic regions in the correct reading frame. The regulation of alternative splicing is essential for various cellular functions in both pathological and physiological conditions. In eukaryotic cells, this process is commonly used to increase proteomic diversity and to control gene expression either co- or post-transcriptionally. Alternative splicing occurs within a megadalton-sized, multi-component machine consisting of RNA and proteins; during the splicing process, this complex undergoes dynamic changes via RNA-RNA, protein-protein and RNA-protein interactions. Co-transcriptional splicing functionally integrates the transcriptional machinery, thereby enabling the two processes to influence one another, whereas post-transcriptional splicing facilitates the coupling of RNA splicing with post-splicing events. This review addresses the structural aspects of spliceosomes and the mechanistic implications of their stepwise assembly on the regulation of pre-mRNA splicing. Moreover, the role of phosphorylation-based, signal-induced changes in the regulation of the splicing process is demonstrated.
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31
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The PSI-U1 snRNP interaction regulates male mating behavior in Drosophila. Proc Natl Acad Sci U S A 2016; 113:5269-74. [PMID: 27114556 DOI: 10.1073/pnas.1600936113] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alternative pre-mRNA splicing (AS) is a critical regulatory mechanism that operates extensively in the nervous system to produce diverse protein isoforms. Fruitless AS isoforms have been shown to influence male courtship behavior, but the underlying mechanisms are unknown. Using genome-wide approaches and quantitative behavioral assays, we show that the P-element somatic inhibitor (PSI) and its interaction with the U1 small nuclear ribonucleoprotein complex (snRNP) control male courtship behavior. PSI mutants lacking the U1 snRNP-interacting domain (PSIΔAB mutant) exhibit extended but futile mating attempts. The PSIΔAB mutant results in significant changes in the AS patterns of ∼1,200 genes in the Drosophila brain, many of which have been implicated in the regulation of male courtship behavior. PSI directly regulates the AS of at least one-third of these transcripts, suggesting that PSI-U1 snRNP interactions coordinate the behavioral network underlying courtship behavior. Importantly, one of these direct targets is fruitless, the master regulator of courtship. Thus, PSI imposes a specific mode of regulatory control within the neuronal circuit controlling courtship, even though it is broadly expressed in the fly nervous system. This study reinforces the importance of AS in the control of gene activity in neurons and integrated neuronal circuits, and provides a surprising link between a pleiotropic pre-mRNA splicing pathway and the precise control of successful male mating behavior.
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32
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Claverie-Martin F, Gonzalez-Paredes FJ, Ramos-Trujillo E. Splicing defects caused by exonic mutations in PKD1 as a new mechanism of pathogenesis in autosomal dominant polycystic kidney disease. RNA Biol 2016; 12:369-74. [PMID: 25757501 DOI: 10.1080/15476286.2015.1014291] [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] [Indexed: 12/12/2022] Open
Abstract
The correct splicing of precursor-mRNA depends on the actual splice sites plus exonic and intronic regulatory elements recognized by the splicing machinery. Surprisingly, an increasing number of examples reveal that exonic mutations disrupt the binding of splicing factors to these sequences or generate new splice sites or regulatory elements, causing disease. This contradicts the general assumption that missense mutations disrupt protein function and that synonymous mutations are merely polymorphisms. Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited disorder caused mainly by mutations in the PKD1 gene. Recently, we analyzed a substantial number of PKD1 missense or synonymous mutations to further characterize their consequences on pre-mRNA splicing. Our results showed that one missense and 2 synonymous mutations induce significant defects in pre-mRNA splicing. Thus, it appears that aberrant splicing as a result of exonic mutations is a previously unrecognized cause of ADPKD.
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Affiliation(s)
- Felix Claverie-Martin
- a Unidad de Investigacion; Hospital Nuestra Señora de Candelaria ; Santa Cruz de Tenerife , Spain
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33
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Papasaikas P, Valcárcel J. The Spliceosome: The Ultimate RNA Chaperone and Sculptor. Trends Biochem Sci 2015; 41:33-45. [PMID: 26682498 DOI: 10.1016/j.tibs.2015.11.003] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 11/02/2015] [Accepted: 11/06/2015] [Indexed: 01/08/2023]
Abstract
The spliceosome, one of the most complex machineries of eukaryotic cells, removes intronic sequences from primary transcripts to generate functional messenger and long noncoding RNAs (lncRNA). Genetic, biochemical, and structural data reveal that the spliceosome is an RNA-based enzyme. Striking mechanistic and structural similarities strongly argue that pre-mRNA introns originated from self-catalytic group II ribozymes. However, in the spliceosome, protein components organize and activate the catalytic-site RNAs, and recognize and pair together splice sites at intron boundaries. The spliceosome is a dynamic, reversible, and flexible machine that chaperones small nuclear (sn) RNAs and a variety of pre-mRNA sequences into conformations that enable intron removal. This malleability likely contributes to the regulation of alternative splicing, a prevalent process contributing to cell differentiation, homeostasis, and disease.
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Affiliation(s)
- Panagiotis Papasaikas
- Centre de Regulació Genòmica, The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu-Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Juan Valcárcel
- Centre de Regulació Genòmica, The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu-Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain; ICREA, Passeig Lluis Companys 23, 08010 Barcelona, Spain.
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34
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Rosenberg AB, Patwardhan RP, Shendure J, Seelig G. Learning the sequence determinants of alternative splicing from millions of random sequences. Cell 2015; 163:698-711. [PMID: 26496609 DOI: 10.1016/j.cell.2015.09.054] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 08/28/2015] [Accepted: 09/21/2015] [Indexed: 01/24/2023]
Abstract
Most human transcripts are alternatively spliced, and many disease-causing mutations affect RNA splicing. Toward better modeling the sequence determinants of alternative splicing, we measured the splicing patterns of over two million (M) synthetic mini-genes, which include degenerate subsequences totaling over 100 M bases of variation. The massive size of these training data allowed us to improve upon current models of splicing, as well as to gain new mechanistic insights. Our results show that the vast majority of hexamer sequence motifs measurably influence splice site selection when positioned within alternative exons, with multiple motifs acting additively rather than cooperatively. Intriguingly, motifs that enhance (suppress) exon inclusion in alternative 5' splicing also enhance (suppress) exon inclusion in alternative 3' or cassette exon splicing, suggesting a universal mechanism for alternative exon recognition. Finally, our empirically trained models are highly predictive of the effects of naturally occurring variants on alternative splicing in vivo.
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Affiliation(s)
- Alexander B Rosenberg
- Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Rupali P Patwardhan
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Georg Seelig
- Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA; Department of Computer Science and Engineering, University of Washington, Seattle, WA 98195, USA.
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35
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Abstract
Precursor messenger RNA (pre-mRNA) splicing is a critical step in the posttranscriptional regulation of gene expression, providing significant expansion of the functional proteome of eukaryotic organisms with limited gene numbers. Split eukaryotic genes contain intervening sequences or introns disrupting protein-coding exons, and intron removal occurs by repeated assembly of a large and highly dynamic ribonucleoprotein complex termed the spliceosome, which is composed of five small nuclear ribonucleoprotein particles, U1, U2, U4/U6, and U5. Biochemical studies over the past 10 years have allowed the isolation as well as compositional, functional, and structural analysis of splicing complexes at distinct stages along the spliceosome cycle. The average human gene contains eight exons and seven introns, producing an average of three or more alternatively spliced mRNA isoforms. Recent high-throughput sequencing studies indicate that 100% of human genes produce at least two alternative mRNA isoforms. Mechanisms of alternative splicing include RNA-protein interactions of splicing factors with regulatory sites termed silencers or enhancers, RNA-RNA base-pairing interactions, or chromatin-based effects that can change or determine splicing patterns. Disease-causing mutations can often occur in splice sites near intron borders or in exonic or intronic RNA regulatory silencer or enhancer elements, as well as in genes that encode splicing factors. Together, these studies provide mechanistic insights into how spliceosome assembly, dynamics, and catalysis occur; how alternative splicing is regulated and evolves; and how splicing can be disrupted by cis- and trans-acting mutations leading to disease states. These findings make the spliceosome an attractive new target for small-molecule, antisense, and genome-editing therapeutic interventions.
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Affiliation(s)
- Yeon Lee
- Center for RNA Systems Biology; Division of Biochemistry, Biophysics, and Structural Biology; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204;
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36
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de Klerk E, 't Hoen PAC. Alternative mRNA transcription, processing, and translation: insights from RNA sequencing. Trends Genet 2015; 31:128-39. [PMID: 25648499 DOI: 10.1016/j.tig.2015.01.001] [Citation(s) in RCA: 226] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 12/22/2014] [Accepted: 01/05/2015] [Indexed: 12/13/2022]
Abstract
The human transcriptome comprises >80,000 protein-coding transcripts and the estimated number of proteins synthesized from these transcripts is in the range of 250,000 to 1 million. These transcripts and proteins are encoded by less than 20,000 genes, suggesting extensive regulation at the transcriptional, post-transcriptional, and translational level. Here we review how RNA sequencing (RNA-seq) technologies have increased our understanding of the mechanisms that give rise to alternative transcripts and their alternative translation. We highlight four different regulatory processes: alternative transcription initiation, alternative splicing, alternative polyadenylation, and alternative translation initiation. We discuss their transcriptome-wide distribution, their impact on protein expression, their biological relevance, and the possible molecular mechanisms leading to their alternative regulation. We conclude with a discussion of the coordination and the interdependence of these four regulatory layers.
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Affiliation(s)
- Eleonora de Klerk
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter A C 't Hoen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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37
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Ayarpadikannan S, Lee HE, Han K, Kim HS. Transposable element-driven transcript diversification and its relevance to genetic disorders. Gene 2015; 558:187-94. [PMID: 25617522 DOI: 10.1016/j.gene.2015.01.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 01/13/2015] [Accepted: 01/20/2015] [Indexed: 12/14/2022]
Abstract
The human genome project and subsequent gene annotation projects have shown that the human genome contains 22,000-25,000 functional genes. Therefore, it is believed that the diversity of protein repertoire is achieved by the alternative splicing (AS) mechanism. Transposable elements (TEs) are mobile in nature and can therefore alter their position in the genome. The insertion of TEs into a new gene region can result in AS of a particular transcript through various mechanisms, including intron retention, and alternative donor or acceptor splice sites. TE-derived AS is thought to have played a part in primate evolution and in hominid radiation. However, TE-derived AS or genetic instability may sometimes result in genetic disorders. For the past two decades, numerous studies have been performed on TEs and their role in genomes. Accumulating evidence shows that the term 'junk DNA', previously used for TEs is a misnomer. Recent research has indicated that TEs may have clinical potential. However, to explore the feasibility of using TEs in clinical practice, additional studies are required. This review summarizes the available literature on TE-derived AS, alternative promoter, and alternative polyadenylation. The review covers the effects of TEs on coding genes and their clinical implications, and provides our perspectives and directions for future research.
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Affiliation(s)
- Selvam Ayarpadikannan
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Hee-Eun Lee
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Kyudong Han
- Department of Nanobiomedical Science, WCU Research Center, Dankook University, Cheonan 330-714, Republic of Korea
| | - Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea.
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38
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Lee Y, Rio DC. Mechanisms and Regulation of Alternative Pre-mRNA Splicing. Annu Rev Biochem 2015. [PMID: 25784052 DOI: 10.1146/annurev-biochem-060614-034316.mechanisms] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Precursor messenger RNA (pre-mRNA) splicing is a critical step in the posttranscriptional regulation of gene expression, providing significant expansion of the functional proteome of eukaryotic organisms with limited gene numbers. Split eukaryotic genes contain intervening sequences or introns disrupting protein-coding exons, and intron removal occurs by repeated assembly of a large and highly dynamic ribonucleoprotein complex termed the spliceosome, which is composed of five small nuclear ribonucleoprotein particles, U1, U2, U4/U6, and U5. Biochemical studies over the past 10 years have allowed the isolation as well as compositional, functional, and structural analysis of splicing complexes at distinct stages along the spliceosome cycle. The average human gene contains eight exons and seven introns, producing an average of three or more alternatively spliced mRNA isoforms. Recent high-throughput sequencing studies indicate that 100% of human genes produce at least two alternative mRNA isoforms. Mechanisms of alternative splicing include RNA-protein interactions of splicing factors with regulatory sites termed silencers or enhancers, RNA-RNA base-pairing interactions, or chromatin-based effects that can change or determine splicing patterns. Disease-causing mutations can often occur in splice sites near intron borders or in exonic or intronic RNA regulatory silencer or enhancer elements, as well as in genes that encode splicing factors. Together, these studies provide mechanistic insights into how spliceosome assembly, dynamics, and catalysis occur; how alternative splicing is regulated and evolves; and how splicing can be disrupted by cis- and trans-acting mutations leading to disease states. These findings make the spliceosome an attractive new target for small-molecule, antisense, and genome-editing therapeutic interventions.
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Affiliation(s)
- Yeon Lee
- Center for RNA Systems Biology; Division of Biochemistry, Biophysics, and Structural Biology; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204;
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Tsugeki R, Tanaka-Sato N, Maruyama N, Terada S, Kojima M, Sakakibara H, Okada K. CLUMSY VEIN, the Arabidopsis DEAH-box Prp16 ortholog, is required for auxin-mediated development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:183-97. [PMID: 25384462 DOI: 10.1111/tpj.12721] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 10/29/2014] [Accepted: 10/31/2014] [Indexed: 05/25/2023]
Abstract
Pre-messenger RNA (pre-mRNA) splicing is essential in eukaryotic cells. In animals and yeasts, the DEAH-box RNA-dependent ATPase Prp16 mediates conformational change of the spliceosome, thereby facilitating pre-mRNA splicing. In yeasts, Prp16 also plays an important role in splicing fidelity. Conversely, PRP16 orthologs in Chlamydomonas reinhardtii and nematode do not have an important role in general pre-mRNA splicing, but are required for gene silencing and sex determination, respectively. Functions of PRP16 orthologs in higher plants have not been described until now. Here we show that the CLUMSY VEIN (CUV) gene encoding the unique Prp16 ortholog in Arabidopsis thaliana facilitates auxin-mediated development including male-gametophyte transmission, apical-basal patterning of embryonic and gynoecium development, stamen development, phyllotactic flower positioning, and vascular development. cuv-1 mutation differentially affects splicing and expression of genes involved in auxin biosynthesis, polar auxin transport, auxin perception and auxin signaling. The cuv-1 mutation does not have an equal influence on pre-mRNA substrates. We propose that Arabidopsis PRP16/CUV differentially facilitates expression of genes, which include genes involved in auxin biosynthesis, transport, perception and signaling, thereby collectively influencing auxin-mediated development.
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Affiliation(s)
- Ryuji Tsugeki
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
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Wickramasinghe VO, Gonzàlez-Porta M, Perera D, Bartolozzi AR, Sibley CR, Hallegger M, Ule J, Marioni JC, Venkitaraman AR. Regulation of constitutive and alternative mRNA splicing across the human transcriptome by PRPF8 is determined by 5' splice site strength. Genome Biol 2015; 16:201. [PMID: 26392272 PMCID: PMC4578845 DOI: 10.1186/s13059-015-0749-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/27/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Sequential assembly of the human spliceosome on RNA transcripts regulates splicing across the human transcriptome. The core spliceosome component PRPF8 is essential for spliceosome assembly through its participation in ribonucleoprotein (RNP) complexes for splice-site recognition, branch-point formation and catalysis. PRPF8 deficiency is linked to human diseases like retinitis pigmentosa or myeloid neoplasia, but its genome-wide effects on constitutive and alternative splicing remain unclear. RESULTS Here, we show that alterations in RNA splicing patterns across the human transcriptome that occur in conditions of restricted cellular PRPF8 abundance are defined by the altered splicing of introns with weak 5' splice sites. iCLIP of spliceosome components reveals that PRPF8 depletion decreases RNP complex formation at most splice sites in exon-intron junctions throughout the genome. However, impaired splicing affects only a subset of human transcripts, enriched for mitotic cell cycle factors, leading to mitotic arrest. Preferentially retained introns and differentially used exons in the affected genes contain weak 5' splice sites, but are otherwise indistinguishable from adjacent spliced introns. Experimental enhancement of splice-site strength in mini-gene constructs overcomes the effects of PRPF8 depletion on the kinetics and fidelity of splicing during transcription. CONCLUSIONS Competition for PRPF8 availability alters the transcription-coupled splicing of RNAs in which weak 5' splice sites predominate, enabling diversification of human gene expression during biological processes like mitosis. Our findings exemplify the regulatory potential of changes in the core spliceosome machinery, which may be relevant to slow-onset human genetic diseases linked to PRPF8 deficiency.
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Affiliation(s)
- Vihandha O. Wickramasinghe
- The Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Box 197, Cambridge, CB2 0XZ UK
| | - Mar Gonzàlez-Porta
- European Molecular Biology Laboratory - European Bioinformatics Institute (EMBL-EBI), Hinxton, UK
| | - David Perera
- The Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Box 197, Cambridge, CB2 0XZ UK
| | - Arthur R. Bartolozzi
- The Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Box 197, Cambridge, CB2 0XZ UK
| | - Christopher R. Sibley
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Martina Hallegger
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Jernej Ule
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - John C. Marioni
- European Molecular Biology Laboratory - European Bioinformatics Institute (EMBL-EBI), Hinxton, UK
| | - Ashok R. Venkitaraman
- The Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Box 197, Cambridge, CB2 0XZ UK
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Regulation of mRNA abundance by polypyrimidine tract-binding protein-controlled alternate 5' splice site choice. PLoS Genet 2014; 10:e1004771. [PMID: 25375251 PMCID: PMC4222953 DOI: 10.1371/journal.pgen.1004771] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 09/22/2014] [Indexed: 11/19/2022] Open
Abstract
Alternative splicing (AS) provides a potent mechanism for increasing protein diversity and modulating gene expression levels. How alternate splice sites are selected by the splicing machinery and how AS is integrated into gene regulation networks remain important questions of eukaryotic biology. Here we report that polypyrimidine tract-binding protein 1 (Ptbp1/PTB/hnRNP-I) controls alternate 5' and 3' splice site (5'ss and 3'ss) usage in a large set of mammalian transcripts. A top scoring event identified by our analysis was the choice between competing upstream and downstream 5'ss (u5'ss and d5'ss) in the exon 18 of the Hps1 gene. Hps1 is essential for proper biogenesis of lysosome-related organelles and loss of its function leads to a disease called type 1 Hermansky-Pudlak Syndrome (HPS). We show that Ptbp1 promotes preferential utilization of the u5'ss giving rise to stable mRNAs encoding a full-length Hps1 protein, whereas bias towards d5'ss triggered by Ptbp1 down-regulation generates transcripts susceptible to nonsense-mediated decay (NMD). We further demonstrate that Ptbp1 binds to pyrimidine-rich sequences between the u5'ss and d5'ss and activates the former site rather than repressing the latter. Consistent with this mechanism, u5'ss is intrinsically weaker than d5'ss, with a similar tendency observed for other genes with Ptbp1-induced u5'ss bias. Interestingly, the brain-enriched Ptbp1 paralog Ptbp2/nPTB/brPTB stimulated the u5'ss utilization but with a considerably lower efficiency than Ptbp1. This may account for the tight correlation between Hps1 with Ptbp1 expression levels observed across mammalian tissues. More generally, these data expand our understanding of AS regulation and uncover a post-transcriptional strategy ensuring co-expression of a subordinate gene with its master regulator through an AS-NMD tracking mechanism.
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Abstract
Sequence-specific RNA-binding proteins (RBPs) bind to pre-mRNA to control alternative splicing, but it is not yet possible to read the 'splicing code' that dictates splicing regulation on the basis of genome sequence. Each alternative splicing event is controlled by multiple RBPs, the combined action of which creates a distribution of alternatively spliced products in a given cell type. As each cell type expresses a distinct array of RBPs, the interpretation of regulatory information on a given RNA target is exceedingly dependent on the cell type. RBPs also control each other's functions at many levels, including by mutual modulation of their binding activities on specific regulatory RNA elements. In this Review, we describe some of the emerging rules that govern the highly context-dependent and combinatorial nature of alternative splicing regulation.
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Affiliation(s)
- Xiang-Dong Fu
- Department of Cellular and Molecular Medicine and Institute for Genomic, Medicine, University of California San Diego, La Jolla, California 92093–0651, USA
| | - Manuel Ares
- Center for Molecular Biology of RNA, and Department of Molecular, Cell, and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
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Parada GE, Munita R, Cerda CA, Gysling K. A comprehensive survey of non-canonical splice sites in the human transcriptome. Nucleic Acids Res 2014; 42:10564-78. [PMID: 25123659 PMCID: PMC4176328 DOI: 10.1093/nar/gku744] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We uncovered the diversity of non-canonical splice sites at the human transcriptome using deep transcriptome profiling. We mapped a total of 3.7 billion human RNA-seq reads and developed a set of stringent filters to avoid false non-canonical splice site detections. We identified 184 splice sites with non-canonical dinucleotides and U2/U12-like consensus sequences. We selected 10 of the herein identified U2/U12-like non-canonical splice site events and successfully validated 9 of them via reverse transcriptase-polymerase chain reaction and Sanger sequencing. Analyses of the 184 U2/U12-like non-canonical splice sites indicate that 51% of them are not annotated in GENCODE. In addition, 28% of them are conserved in mouse and 76% are involved in alternative splicing events, some of them with tissue-specific alternative splicing patterns. Interestingly, our analysis identified some U2/U12-like non-canonical splice sites that are converted into canonical splice sites by RNA A-to-I editing. Moreover, the U2/U12-like non-canonical splice sites have a differential distribution of splicing regulatory sequences, which may contribute to their recognition and regulation. Our analysis provides a high-confidence group of U2/U12-like non-canonical splice sites, which exhibit distinctive features among the total human splice sites.
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Affiliation(s)
- Guillermo E Parada
- Nucleus Millennium in Stress and Addiction, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Roberto Munita
- Nucleus Millennium in Stress and Addiction, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Cledi A Cerda
- Nucleus Millennium in Stress and Addiction, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Katia Gysling
- Nucleus Millennium in Stress and Addiction, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
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Abstract
One of the most amazing findings in molecular biology was the discovery that eukaryotic genes are discontinuous, with coding DNA being interrupted by stretches of non-coding sequence. The subsequent realization that the intervening regions are removed from pre-mRNA transcripts via the activity of a common set of small nuclear RNAs (snRNAs), which assemble together with associated proteins into a complex known as the spliceosome, was equally surprising. How do cells coordinate the assembly of this molecular machine? And how does the spliceosome accurately recognize exons and introns to carry out the splicing reaction? Insights into these questions have been gained by studying the life cycle of spliceosomal snRNAs from their transcription, nuclear export and re-import to their dynamic assembly into the spliceosome. This assembly process can also affect the regulation of alternative splicing and has implications for human disease.
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Affiliation(s)
- A Gregory Matera
- Department of Biology, Department of Genetics and Integrative Program for Biological and Genome Sciences, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Zefeng Wang
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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McManus CJ, Coolon JD, Eipper-Mains J, Wittkopp PJ, Graveley BR. Evolution of splicing regulatory networks in Drosophila. Genome Res 2014; 24:786-96. [PMID: 24515119 PMCID: PMC4009608 DOI: 10.1101/gr.161521.113] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The proteome expanding effects of alternative pre-mRNA splicing have had a profound impact on eukaryotic evolution. The events that create this diversity can be placed into four major classes: exon skipping, intron retention, alternative 5′ splice sites, and alternative 3′ splice sites. Although the regulatory mechanisms and evolutionary pressures among alternative splicing classes clearly differ, how these differences affect the evolution of splicing regulation remains poorly characterized. We used RNA-seq to investigate splicing differences in D. simulans, D. sechellia, and three strains of D. melanogaster. Regulation of exon skipping and tandem alternative 3′ splice sites (NAGNAGs) were more divergent than other splicing classes. Splicing regulation was most divergent in frame-preserving events and events in noncoding regions. We further determined the contributions of cis- and trans-acting changes in splicing regulatory networks by comparing allele-specific splicing in F1 interspecific hybrids, because differences in allele-specific splicing reflect changes in cis-regulatory element activity. We find that species-specific differences in intron retention and alternative splice site usage are primarily attributable to changes in cis-regulatory elements (median ∼80% cis), whereas species-specific exon skipping differences are driven by both cis- and trans-regulatory divergence (median ∼50% cis). These results help define the mechanisms and constraints that influence splicing regulatory evolution and show that networks regulating the four major classes of alternative splicing diverge through different genetic mechanisms. We propose a model in which differences in regulatory network architecture among classes of alternative splicing affect the evolution of splicing regulation.
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Affiliation(s)
- C Joel McManus
- Department of Genetics and Developmental Biology, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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Wang Y, Wang Z. Systematical identification of splicing regulatory cis-elements and cognate trans-factors. Methods 2014; 65:350-8. [PMID: 23974071 PMCID: PMC3932149 DOI: 10.1016/j.ymeth.2013.08.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/09/2013] [Accepted: 08/12/2013] [Indexed: 01/22/2023] Open
Abstract
The majority of human genes undergo alternative splicing to generate multiple isoforms with distinct functions. This process is generally controlled by cis-acting splicing regulatory elements (SREs) that recruit trans-acting factors to promote or inhibit the use of nearby splice sites. The growing interest in understanding the regulatory rules of splicing necessitates the systematic identification of these SREs and their cognate protein factors using experimental and computational approaches. Here we describe a strategy to identify and analyze both cis-acting SREs and trans-acting splicing factors. This strategy involves a cell-based screen to identify SREs from a random sequences library and a modified RNA affinity purification approach to unbiasedly identify the splicing factors. These methods can be adopted to identify splicing enhancers or silencers in both exons and introns, and can be extended to different cultured cells. The resulting SREs and splicing factors can be further analyzed with a series of computational and experimental approaches. This approach will help us to collect a molecular part-list for splicing regulation, providing a rich data source that enables a better understanding of the "splicing code".
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Affiliation(s)
- Yang Wang
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, United States.
| | - Zefeng Wang
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, United States.
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Sterne-Weiler T, Sanford JR. Exon identity crisis: disease-causing mutations that disrupt the splicing code. Genome Biol 2014; 15:201. [PMID: 24456648 PMCID: PMC4053859 DOI: 10.1186/gb4150] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cis-acting RNA elements control the accurate expression of human multi-exon protein coding genes. Single nucleotide variants altering the fidelity of this regulatory code and, consequently, pre-mRNA splicing are expected to contribute to the etiology of numerous human diseases.
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Zhou X, Wu W, Li H, Cheng Y, Wei N, Zong J, Feng X, Xie Z, Chen D, Manley JL, Wang H, Feng Y. Transcriptome analysis of alternative splicing events regulated by SRSF10 reveals position-dependent splicing modulation. Nucleic Acids Res 2014; 42:4019-30. [PMID: 24442672 PMCID: PMC3973337 DOI: 10.1093/nar/gkt1387] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Splicing factor SRSF10 is known to function as a sequence-specific splicing activator. Here, we used RNA-seq coupled with bioinformatics analysis to identify the extensive splicing network regulated by SRSF10 in chicken cells. We found that SRSF10 promoted both exon inclusion and exclusion. Motif analysis revealed that SRSF10 binding to cassette exons was associated with exon inclusion, whereas the binding of SRSF10 within downstream constitutive exons was associated with exon exclusion. This positional effect was further demonstrated by the mutagenesis of potential SRSF10 binding motifs in two minigene constructs. Functionally, many of SRSF10-verified alternative exons are linked to pathways of stress and apoptosis. Consistent with this observation, cells depleted of SRSF10 expression were far more susceptible to endoplasmic reticulum stress-induced apoptosis than control cells. Importantly, reconstituted SRSF10 in knockout cells recovered wild-type splicing patterns and considerably rescued the stress-related defects. Together, our results provide mechanistic insight into SRSF10-regulated alternative splicing events in vivo and demonstrate that SRSF10 plays a crucial role in cell survival under stress conditions.
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Affiliation(s)
- Xuexia Zhou
- Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China, Novel Bioinformatics Co., Ltd, Shanghai, China, Department of Biological Sciences, Columbia University, New York, NY 10027, USA and Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing 100021, China
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Abstract
Alternative splicing plays a prevalent role in generating functionally diversified proteomes from genomes with a more limited repertoire of protein-coding genes. Alternative splicing is frequently regulated with cell type or developmental specificity and in response to signaling pathways, and its mis-regulation can lead to disease. Co-regulated programs of alternative splicing involve interplay between a host of cis-acting transcript features and trans-acting RNA-binding proteins. Here, we review the current state of understanding of the logic and mechanism of regulated alternative splicing and indicate how this understanding can be exploited to manipulate splicing for therapeutic purposes.
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Affiliation(s)
- Miguel B Coelho
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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Abstract
Alternative splicing of pre-mRNA is a complex process whose outcome depends on elements reviewed in the previous chapters such as the core spliceosome units, how the core spliceosome units interact between themselves and with other splicing enhancers and repressors, primary sequence motifs, and local RNA secondary structure. Connections between RNA splicing, transcription, and other processes have also been reviewed in the previous chapters. Splicing is inherently a stochastic process: Some defective transcripts are produced and handled by mechanisms such as nonsense-mediated decay (NMD), and studies report high variability at the transcript level between cells supposedly in similar states. Nonetheless, splicing is obviously not a random process: Many determinants of splicing regulation have been identified, and experimental measurements detect highly robust and conserved splicing changes between developmental stages and tissues. These observations naturally lead to the following questions: Can we devise a method that predicts given a cellular context and the primary transcript what would be the splicing outcome? What can such a method tell us about the underlying mechanisms that govern alternative splicing?This chapter describes how these questions can be framed and addressed using machine-learning methodology. We describe how to extract putative RNA regulatory features from genomic sequence of exons and proximal introns, how to define target values based on experimental measurements of exon inclusion, how to learn a simple splicing model that optimizes the prediction the observed exon inclusion levels from the identified RNA features, and how to subsequently evaluate the learned model accuracy.
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Affiliation(s)
- Yoseph Barash
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
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