1
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Olthof AM, Schwoerer CF, Girardini KN, Weber AL, Doggett K, Mieruszynski S, Heath JK, Moore TE, Biran J, Kanadia RN. Taxonomy of introns and the evolution of minor introns. Nucleic Acids Res 2024:gkae550. [PMID: 38943346 DOI: 10.1093/nar/gkae550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 06/05/2024] [Accepted: 06/13/2024] [Indexed: 07/01/2024] Open
Abstract
Classification of introns, which is crucial to understanding their evolution and splicing, has historically been binary and has resulted in the naming of major and minor introns that are spliced by their namesake spliceosome. However, a broad range of intron consensus sequences exist, leading us to here reclassify introns as minor, minor-like, hybrid, major-like, major and non-canonical introns in 263 species across six eukaryotic supergroups. Through intron orthology analysis, we discovered that minor-like introns are a transitory node for intron conversion across evolution. Despite close resemblance of their consensus sequences to minor introns, these introns possess an AG dinucleotide at the -1 and -2 position of the 5' splice site, a salient feature of major introns. Through combined analysis of CoLa-seq, CLIP-seq for major and minor spliceosome components, and RNAseq from samples in which the minor spliceosome is inhibited we found that minor-like introns are also an intermediate class from a splicing mechanism perspective. Importantly, this analysis has provided insight into the sequence elements that have evolved to make minor-like introns amenable to recognition by both minor and major spliceosome components. We hope that this revised intron classification provides a new framework to study intron evolution and splicing.
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Affiliation(s)
- Anouk M Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Charles F Schwoerer
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Kaitlin N Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Audrey L Weber
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Karen Doggett
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Stephen Mieruszynski
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Joan K Heath
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Timothy E Moore
- Statistical Consulting Services, Center for Open Research Resources & Equipment, University of Connecticut, Storrs, CT, USA
| | - Jakob Biran
- Department of Poultry and Aquaculture, Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon, Israel
| | - Rahul N Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
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2
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Nagasawa CK, Bailey AO, Russell WK, Garcia-Blanco MA. Inefficient recruitment of DDX39B impedes pre-spliceosome assembly on FOXP3 introns. RNA (NEW YORK, N.Y.) 2024; 30:824-838. [PMID: 38575347 PMCID: PMC11182011 DOI: 10.1261/rna.079933.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/19/2024] [Indexed: 04/06/2024]
Abstract
Forkhead box P3 (FOXP3) is the master fate-determining transcription factor in regulatory T (Treg) cells and is essential for their development, function, and homeostasis. Mutations in FOXP3 cause immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome, and aberrant expression of FOXP3 has been implicated in other diseases such as multiple sclerosis and cancer. We previously demonstrated that pre-mRNA splicing of FOXP3 RNAs is highly sensitive to levels of DExD-box polypeptide 39B (DDX39B), and here we investigate the mechanism of this sensitivity. FOXP3 introns have cytidine (C)-rich/uridine (U)-poor polypyrimidine (py) tracts that are responsible for their inefficient splicing and confer sensitivity to DDX39B. We show that there is a deficiency in the assembly of commitment complexes (CCs) on FOXP3 introns, which is consistent with the lower affinity of U2AF2 for C-rich/U-poor py tracts. Our data indicate an even stronger effect on the conversion of CCs to pre-spliceosomes. We propose that this is due to an altered conformation that U2AF2 adopts when it binds to C-rich/U-poor py tracts and that this conformation has a lower affinity for DDX39B. As a consequence, CCs assembled on FOXP3 introns are defective in recruiting DDX39B, and this leads to the inefficient assembly of pre-spliceosome complexes.
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Affiliation(s)
- Chloe K Nagasawa
- Human Pathophysiology and Translational Medicine Program, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77550, USA
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77550, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Aaron O Bailey
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77550, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77550, USA
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77550, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA
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3
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Li H, Ding Z, Fang ZY, Long N, Ang HY, Zhang Y, Fan YJ, Xu YZ. Conserved intronic secondary structures with concealed branch sites regulate alternative splicing of poison exons. Nucleic Acids Res 2024; 52:6002-6016. [PMID: 38499485 PMCID: PMC11162794 DOI: 10.1093/nar/gkae185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 02/23/2024] [Accepted: 03/05/2024] [Indexed: 03/20/2024] Open
Abstract
Alternative splicing (AS) generates multiple RNA isoforms and increases the complexities of transcriptomes and proteomes. However, it remains unclear how RNA structures contribute to AS regulation. Here, we systematically search transcriptomes for secondary structures with concealed branch sites (BSs) in the alternatively spliced introns and predict thousands of them from six organisms, of which many are evolutionarily conserved. Intriguingly, a highly conserved stem-loop structure with concealed BSs is found in animal SF3B3 genes and colocalizes with a downstream poison exon (PE). Destabilization of this structure allows increased usage of the BSs and results in enhanced PE inclusion in human and Drosophila cells, leading to decreased expression of SF3B3. This structure is experimentally validated using an in-cell SHAPE-MaP assay. Through RNA interference screens of 28 RNA-binding proteins, we find that this stem-loop structure is sensitive to U2 factors. Furthermore, we find that SF3B3 also facilitates DNA repair and protects genome stability by enhancing interaction between ERCC6/CSB and arrested RNA polymerase II. Importantly, both Drosophila and human cells with the secondary structure mutated by genome editing exhibit altered DNA repair in vivo. This study provides a novel and common mechanism for AS regulation of PEs and reveals a physiological function of SF3B3 in DNA repair.
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Affiliation(s)
- Hao Li
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Hubei 430072, China
| | - Zhan Ding
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Hubei 430072, China
| | - Zhuo-Ya Fang
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Hubei 430072, China
| | - Ni Long
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Hubei 430072, China
| | - Hao-Yang Ang
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Hubei 430072, China
| | - Yu Zhang
- Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore, 138672, Singapore
| | - Yu-Jie Fan
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Hubei 430072, China
| | - Yong-Zhen Xu
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, Hubei 430072, China
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4
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Emilius L, Bremm F, Binder AK, Schaft N, Dörrie J. Tumor Antigens beyond the Human Exome. Int J Mol Sci 2024; 25:4673. [PMID: 38731892 PMCID: PMC11083240 DOI: 10.3390/ijms25094673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024] Open
Abstract
With the advent of immunotherapeutics, a new era in the combat against cancer has begun. Particularly promising are neo-epitope-targeted therapies as the expression of neo-antigens is tumor-specific. In turn, this allows the selective targeting and killing of cancer cells whilst healthy cells remain largely unaffected. So far, many advances have been made in the development of treatment options which are tailored to the individual neo-epitope repertoire. The next big step is the achievement of efficacious "off-the-shelf" immunotherapies. For this, shared neo-epitopes propose an optimal target. Given the tremendous potential, a thorough understanding of the underlying mechanisms which lead to the formation of neo-antigens is of fundamental importance. Here, we review the various processes which result in the formation of neo-epitopes. Broadly, the origin of neo-epitopes can be categorized into three groups: canonical, noncanonical, and viral neo-epitopes. For the canonical neo-antigens that arise in direct consequence of somatic mutations, we summarize past and recent findings. Beyond that, our main focus is put on the discussion of noncanonical and viral neo-epitopes as we believe that targeting those provides an encouraging perspective to shape the future of cancer immunotherapeutics.
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Affiliation(s)
- Lisabeth Emilius
- Department of Dermatology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; (L.E.); (F.B.); (A.K.B.); (J.D.)
- Comprehensive Cancer Center Erlangen European Metropolitan Area of Nuremberg (CCC ER-EMN), 91054 Erlangen, Germany
- Deutsches Zentrum Immuntherapie (DZI), 91054 Erlangen, Germany
- Bavarian Cancer Research Center (BZKF), 91054 Erlangen, Germany
| | - Franziska Bremm
- Department of Dermatology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; (L.E.); (F.B.); (A.K.B.); (J.D.)
- Comprehensive Cancer Center Erlangen European Metropolitan Area of Nuremberg (CCC ER-EMN), 91054 Erlangen, Germany
- Deutsches Zentrum Immuntherapie (DZI), 91054 Erlangen, Germany
- Bavarian Cancer Research Center (BZKF), 91054 Erlangen, Germany
| | - Amanda Katharina Binder
- Department of Dermatology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; (L.E.); (F.B.); (A.K.B.); (J.D.)
- Comprehensive Cancer Center Erlangen European Metropolitan Area of Nuremberg (CCC ER-EMN), 91054 Erlangen, Germany
- Deutsches Zentrum Immuntherapie (DZI), 91054 Erlangen, Germany
- Bavarian Cancer Research Center (BZKF), 91054 Erlangen, Germany
| | - Niels Schaft
- Department of Dermatology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; (L.E.); (F.B.); (A.K.B.); (J.D.)
- Comprehensive Cancer Center Erlangen European Metropolitan Area of Nuremberg (CCC ER-EMN), 91054 Erlangen, Germany
- Deutsches Zentrum Immuntherapie (DZI), 91054 Erlangen, Germany
- Bavarian Cancer Research Center (BZKF), 91054 Erlangen, Germany
| | - Jan Dörrie
- Department of Dermatology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; (L.E.); (F.B.); (A.K.B.); (J.D.)
- Comprehensive Cancer Center Erlangen European Metropolitan Area of Nuremberg (CCC ER-EMN), 91054 Erlangen, Germany
- Deutsches Zentrum Immuntherapie (DZI), 91054 Erlangen, Germany
- Bavarian Cancer Research Center (BZKF), 91054 Erlangen, Germany
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5
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Fukumura K, Sperotto L, Seuß S, Kang HS, Yoshimoto R, Sattler M, Mayeda A. SAP30BP interacts with RBM17/SPF45 to promote splicing in a subset of human short introns. Cell Rep 2023; 42:113534. [PMID: 38065098 DOI: 10.1016/j.celrep.2023.113534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 11/03/2023] [Accepted: 11/16/2023] [Indexed: 12/30/2023] Open
Abstract
Human pre-mRNA splicing requires the removal of introns with highly variable lengths, from tens to over a million nucleotides. Therefore, mechanisms of intron recognition and splicing are likely not universal. Recently, we reported that splicing in a subset of human short introns with truncated polypyrimidine tracts depends on RBM17 (SPF45), instead of the canonical splicing factor U2 auxiliary factor (U2AF) heterodimer. Here, we demonstrate that SAP30BP, a factor previously implicated in transcriptional control, is an essential splicing cofactor for RBM17. In vitro binding and nuclear magnetic resonance analyses demonstrate that a U2AF-homology motif (UHM) in RBM17 binds directly to a newly identified UHM-ligand motif in SAP30BP. We show that this RBM17-SAP30BP interaction is required to specifically recruit RBM17 to phosphorylated SF3B1 (SF3b155), a U2 small nuclear ribonucleoprotein (U2 snRNP) component in active spliceosomes. We propose a mechanism for splicing in a subset of short introns, in which SAP30BP guides RBM17 in the assembly of active spliceosomes.
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Affiliation(s)
- Kazuhiro Fukumura
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
| | - Luca Sperotto
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Stefanie Seuß
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Hyun-Seo Kang
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Rei Yoshimoto
- Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Hirakata, Osaka 673-0101, Japan
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
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6
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Xie J, Wang L, Lin RJ. Variations of intronic branchpoint motif: identification and functional implications in splicing and disease. Commun Biol 2023; 6:1142. [PMID: 37949953 PMCID: PMC10638238 DOI: 10.1038/s42003-023-05513-7] [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: 07/28/2023] [Accepted: 10/26/2023] [Indexed: 11/12/2023] Open
Abstract
The branchpoint (BP) motif is an essential intronic element for spliceosomal pre-mRNA splicing. In mammals, its sequence composition, distance to the downstream exon, and number of BPs per 3´ splice site are highly variable, unlike the GT/AG dinucleotides at the intron ends. These variations appear to provide evolutionary advantages for fostering alternative splicing, satisfying more diverse cellular contexts, and promoting resilience to genetic changes, thus contributing to an extra layer of complexity for gene regulation. Importantly, variants in the BP motif itself or in genes encoding BP-interacting factors cause human genetic diseases or cancers, highlighting the critical function of BP motif and the need to precisely identify functional BPs for faithful interpretation of their roles in splicing. In this perspective, we will succinctly summarize the major findings related to BP motif variations, discuss the relevant issues/challenges, and provide our insights.
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Affiliation(s)
- Jiuyong Xie
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
| | - Lili Wang
- Department of Systems Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, 91010, USA.
| | - Ren-Jang Lin
- Center for RNA Biology & Therapeutics, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, 91010, USA.
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7
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Ebersberger S, Hipp C, Mulorz MM, Buchbender A, Hubrich D, Kang HS, Martínez-Lumbreras S, Kristofori P, Sutandy FXR, Llacsahuanga Allcca L, Schönfeld J, Bakisoglu C, Busch A, Hänel H, Tretow K, Welzel M, Di Liddo A, Möckel MM, Zarnack K, Ebersberger I, Legewie S, Luck K, Sattler M, König J. FUBP1 is a general splicing factor facilitating 3' splice site recognition and splicing of long introns. Mol Cell 2023:S1097-2765(23)00516-6. [PMID: 37506698 DOI: 10.1016/j.molcel.2023.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 05/19/2023] [Accepted: 07/03/2023] [Indexed: 07/30/2023]
Abstract
Splicing of pre-mRNAs critically contributes to gene regulation and proteome expansion in eukaryotes, but our understanding of the recognition and pairing of splice sites during spliceosome assembly lacks detail. Here, we identify the multidomain RNA-binding protein FUBP1 as a key splicing factor that binds to a hitherto unknown cis-regulatory motif. By collecting NMR, structural, and in vivo interaction data, we demonstrate that FUBP1 stabilizes U2AF2 and SF1, key components at the 3' splice site, through multivalent binding interfaces located within its disordered regions. Transcriptional profiling and kinetic modeling reveal that FUBP1 is required for efficient splicing of long introns, which is impaired in cancer patients harboring FUBP1 mutations. Notably, FUBP1 interacts with numerous U1 snRNP-associated proteins, suggesting a unique role for FUBP1 in splice site bridging for long introns. We propose a compelling model for 3' splice site recognition of long introns, which represent 80% of all human introns.
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Affiliation(s)
| | - Clara Hipp
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany
| | - Miriam M Mulorz
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | | | - Dalmira Hubrich
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Hyun-Seo Kang
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany
| | - Santiago Martínez-Lumbreras
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany
| | - Panajot Kristofori
- Department of Systems Biology, Institute for Biomedical Genetics (IBMG), University of Stuttgart, 70569 Stuttgart, Germany
| | | | | | - Jonas Schönfeld
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Cem Bakisoglu
- Buchmann Institute for Molecular Life Sciences & Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Anke Busch
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Heike Hänel
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Kerstin Tretow
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Mareen Welzel
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | | | - Martin M Möckel
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences & Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; CardioPulmonary Institute (CPI), 35392 Gießen, Germany
| | - Ingo Ebersberger
- Applied Bioinformatics Group, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; Senckenberg Biodiversity and Climate Research Center (S-BIK-F), 60325 Frankfurt am Main, Germany; LOEWE Center for Translational Biodiversity Genomics (TBG), 60325 Frankfurt am Main, Germany
| | - Stefan Legewie
- Department of Systems Biology, Institute for Biomedical Genetics (IBMG), University of Stuttgart, 70569 Stuttgart, Germany; Stuttgart Research Center for Systems Biology (SRCSB), University of Stuttgart, 70569 Stuttgart, Germany
| | - Katja Luck
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany.
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany.
| | - Julian König
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany.
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8
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Nagasawa CK, Garcia-Blanco MA. Early Splicing Complexes and Human Disease. Int J Mol Sci 2023; 24:11412. [PMID: 37511171 PMCID: PMC10379813 DOI: 10.3390/ijms241411412] [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: 06/18/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
Over the last decade, our understanding of spliceosome structure and function has significantly improved, refining the study of the impact of dysregulated splicing on human disease. As a result, targeted splicing therapeutics have been developed, treating various diseases including spinal muscular atrophy and Duchenne muscular dystrophy. These advancements are very promising and emphasize the critical role of proper splicing in maintaining human health. Herein, we provide an overview of the current information on the composition and assembly of early splicing complexes-commitment complex and pre-spliceosome-and their association with human disease.
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Affiliation(s)
- Chloe K. Nagasawa
- Human Pathophysiology and Translational Medicine Program, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX 77555-5302, USA;
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22903-2628, USA
| | - Mariano A. Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22903-2628, USA
- Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
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9
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Cieśla M, Ngoc PCT, Muthukumar S, Todisco G, Madej M, Fritz H, Dimitriou M, Incarnato D, Hellström-Lindberg E, Bellodi C. m 6A-driven SF3B1 translation control steers splicing to direct genome integrity and leukemogenesis. Mol Cell 2023; 83:1165-1179.e11. [PMID: 36944332 DOI: 10.1016/j.molcel.2023.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 01/07/2023] [Accepted: 02/20/2023] [Indexed: 03/22/2023]
Abstract
SF3B1 is the most mutated splicing factor (SF) in myelodysplastic syndromes (MDSs), which are clonal hematopoietic disorders with variable risk of leukemic transformation. Although tumorigenic SF3B1 mutations have been extensively characterized, the role of "non-mutated" wild-type SF3B1 in cancer remains largely unresolved. Here, we identify a conserved epitranscriptomic program that steers SF3B1 levels to counteract leukemogenesis. Our analysis of human and murine pre-leukemic MDS cells reveals dynamic regulation of SF3B1 protein abundance, which affects MDS-to-leukemia progression in vivo. Mechanistically, ALKBH5-driven 5' UTR m6A demethylation fine-tunes SF3B1 translation directing splicing of central DNA repair and epigenetic regulators during transformation. This impacts genome stability and leukemia progression in vivo, supporting an integrative analysis in humans that SF3B1 molecular signatures may predict mutational variability and poor prognosis. These findings highlight a post-transcriptional gene expression nexus that unveils unanticipated SF3B1-dependent cancer vulnerabilities.
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Affiliation(s)
- Maciej Cieśla
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184 Lund, Sweden; International Institute of Molecular Mechanisms and Machines, Polish Academy of Sciences, Warsaw, Poland.
| | - Phuong Cao Thi Ngoc
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184 Lund, Sweden
| | - Sowndarya Muthukumar
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184 Lund, Sweden
| | - Gabriele Todisco
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Magdalena Madej
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184 Lund, Sweden
| | - Helena Fritz
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184 Lund, Sweden
| | - Marios Dimitriou
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Danny Incarnato
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, the Netherlands
| | - Eva Hellström-Lindberg
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Cristian Bellodi
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184 Lund, Sweden.
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10
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Wei AZ, Maniar AB, Carvajal RD. New targeted and epigenetic therapeutic strategies for the treatment of uveal melanoma. Cancer Gene Ther 2022; 29:1819-1826. [PMID: 35236928 DOI: 10.1038/s41417-022-00443-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 01/14/2022] [Accepted: 02/08/2022] [Indexed: 02/07/2023]
Abstract
Uveal melanoma (UM) is a rare, genetically bland ocular malignancy with excellent local treatment options, but no disease-specific therapies are approved for use in the metastatic setting by the Food and Drug Administration. Metastatic UM (mUM) confers a prognosis of ~15 months. Unlike cutaneous melanoma, UM is poorly responsive to checkpoint inhibitors and cytotoxic chemotherapy highlighting the importance of clarifying vulnerable disease-specific mechanisms, such as cell cycle or metabolic pathways necessary for tumor growth and survival. The elucidation of signaling pathways downstream of the frequently mutated GNA GTPase such as PKC/MAPK/ERK/MEK, PI3K/AKT, and YAP-Hippo have offered potential targets. Potentially druggable epigenetic targets due to BAP1-mutated UM have also been identified, including proteins involved with histone deacetylation and DNA splicing. This review describes the preclinical rationale for the development of targeted therapies and current strategies currently being studied in clinical trials or will be in the near future.
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Affiliation(s)
- Alexander Z Wei
- Columbia University Irving Medical Center, New York, New York, USA
| | - Ashray B Maniar
- Columbia University Irving Medical Center, New York, New York, USA
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11
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North K, Benbarche S, Liu B, Pangallo J, Chen S, Stahl M, Bewersdorf JP, Stanley RF, Erickson C, Cho H, Pineda JMB, Thomas JD, Polaski JT, Belleville AE, Gabel AM, Udy DB, Humbert O, Kiem HP, Abdel-Wahab O, Bradley RK. Synthetic introns enable splicing factor mutation-dependent targeting of cancer cells. Nat Biotechnol 2022; 40:1103-1113. [PMID: 35241838 PMCID: PMC9288984 DOI: 10.1038/s41587-022-01224-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 01/17/2022] [Indexed: 11/16/2022]
Abstract
Many cancers carry recurrent, change-of-function mutations affecting RNA splicing factors. Here, we describe a method to harness this abnormal splicing activity to drive splicing factor mutation-dependent gene expression to selectively eliminate tumor cells. We engineered synthetic introns that were efficiently spliced in cancer cells bearing SF3B1 mutations, but unspliced in otherwise isogenic wild-type cells, to yield mutation-dependent protein production. A massively parallel screen of 8,878 introns delineated ideal intronic size and mapped elements underlying mutation-dependent splicing. Synthetic introns enabled mutation-dependent expression of herpes simplex virus-thymidine kinase (HSV-TK) and subsequent ganciclovir (GCV)-mediated killing of SF3B1-mutant leukemia, breast cancer, uveal melanoma and pancreatic cancer cells in vitro, while leaving wild-type cells unaffected. Delivery of synthetic intron-containing HSV-TK constructs to leukemia, breast cancer and uveal melanoma cells and GCV treatment in vivo significantly suppressed the growth of these otherwise lethal xenografts and improved mouse host survival. Synthetic introns provide a means to exploit tumor-specific changes in RNA splicing for cancer gene therapy.
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Affiliation(s)
- Khrystyna North
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Salima Benbarche
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Bo Liu
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Joseph Pangallo
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, USA
| | - Sisi Chen
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Maximilian Stahl
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jan Philipp Bewersdorf
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Robert F Stanley
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Caroline Erickson
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Hana Cho
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jose Mario Bello Pineda
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - James D Thomas
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Jacob T Polaski
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Andrea E Belleville
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Austin M Gabel
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Dylan B Udy
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, USA
| | - Olivier Humbert
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Hans-Peter Kiem
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
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12
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Galardi JW, Bela VN, Jeffery N, He X, Glasser E, Loerch S, Jenkins JL, Pulvino MJ, Boutz PL, Kielkopf CL. A UHM - ULM interface with unusual structural features contributes to U2AF2 and SF3B1 association for pre-mRNA splicing. J Biol Chem 2022; 298:102224. [PMID: 35780835 PMCID: PMC9364107 DOI: 10.1016/j.jbc.2022.102224] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 06/17/2022] [Accepted: 06/18/2022] [Indexed: 11/30/2022] Open
Abstract
During spliceosome assembly, the 3′ splice site is recognized by sequential U2AF2 complexes, first with Splicing Factor 1 (SF1) and second by the SF3B1 subunit of the U2 small nuclear ribonuclear protein particle. The U2AF2–SF1 interface is well characterized, comprising a U2AF homology motif (UHM) of U2AF2 bound to a U2AF ligand motif (ULM) of SF1. However, the structure of the U2AF2–SF3B1 interface and its importance for pre-mRNA splicing are unknown. To address this knowledge gap, we determined the crystal structure of the U2AF2 UHM bound to a SF3B1 ULM site at 1.8-Å resolution. We discovered a distinctive trajectory of the SF3B1 ULM across the U2AF2 UHM surface, which differs from prior UHM/ULM structures and is expected to modulate the orientations of the full-length proteins. We established that the binding affinity of the U2AF2 UHM for the cocrystallized SF3B1 ULM rivals that of a nearly full-length U2AF2 protein for an N-terminal SF3B1 region. An additional SF3B6 subunit had no detectable effect on the U2AF2–SF3B1 binding affinities. We further showed that key residues at the U2AF2 UHM–SF3B1 ULM interface contribute to coimmunoprecipitation of the splicing factors. Moreover, disrupting the U2AF2–SF3B1 interface changed splicing of representative human transcripts. From analysis of genome-wide data, we found that many of the splice sites coregulated by U2AF2 and SF3B1 differ from those coregulated by U2AF2 and SF1. Taken together, these findings support distinct structural and functional roles for the U2AF2—SF1 and U2AF2—SF3B1 complexes during the pre-mRNA splicing process.
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Affiliation(s)
- Justin W Galardi
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Victoria N Bela
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Nazish Jeffery
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Xueyang He
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Eliezra Glasser
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Sarah Loerch
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Jermaine L Jenkins
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Mary J Pulvino
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Paul L Boutz
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Clara L Kielkopf
- Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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13
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Ma L, Liang B, Hu H, Yang W, Lin S, Cao L, Li K, Kuang Y, Shou L, Jin W, Lan J, Ye X, Le J, Lei H, Fu J, Lin Y, Jiang W, Zheng Z, Jiang S, Fu L, Su C, Yin X, Liu L, Qin J, Jin J, Qian S, Ouyang G, Tong H. A Novel Prognostic Scoring Model for Myelodysplastic Syndrome Patients With SF3B1 Mutation. Front Oncol 2022; 12:905490. [PMID: 35832562 PMCID: PMC9271788 DOI: 10.3389/fonc.2022.905490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 05/27/2022] [Indexed: 11/30/2022] Open
Abstract
The outcomes of myelodysplastic syndrome (MDS) patients with SF3B1 mutation, despite identified as a favorable prognostic biomarker, are variable. To comprehend the heterogeneity in clinical characteristics and outcomes, we reviewed 140 MDS patients with SF3B1 mutation in Zhejiang province of China. Seventy-three (52.1%) patients diagnosed as MDS with ring sideroblasts (MDS-RS) following the 2016 World Health Organization (WHO) classification and 118 (84.3%) patients belonged to lower risk following the revised International Prognostic Scoring System (IPSS-R). Although clonal hematopoiesis-associated mutations containing TET2, ASXL1 and DNMT3A were the most frequent co-mutant genes in these patients, RUNX1, EZH2, NF1 and KRAS/NRAS mutations had significant effects on overall survival (OS). Based on that we developed a risk scoring model as IPSS-R×0.4+RUNX1×1.1+EZH2×0.6+RAS×0.9+NF1×1.6. Patients were categorized into two subgroups: low-risk (L-R, score <= 1.4) group and high risk (H-R, score > 1.4) group. The 3-year OS for the L-R and H-R groups was 91.88% (95% CI, 83.27%-100%) and 38.14% (95% CI, 24.08%-60.40%), respectively (P<0.001). This proposed model distinctly outperformed the widely used IPSS-R. In summary, we constructed and validated a personalized prediction model of MDS patients with SF3B1 mutation that can better predict the survival of these patients.
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Affiliation(s)
- Liya Ma
- Department of Hematology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Bin Liang
- Department of Hematology, The First Affiliated Hospital of Wenzhou University, Wenzhou, China
| | - Huixian Hu
- Department of Hematology, Jinhua Central Hospital, Jinhua, China
| | - Wenli Yang
- Department of Hematology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Shengyun Lin
- Department of Hematology, Zhejiang Provincial Hospital of Chinese Medicine, Hangzhou, China
| | - Lihong Cao
- Department of Hematology, Shulan Hospital of Zhejiang Province, Hangzhou, China
| | - Kongfei Li
- Department of Hematology, Ningbo Yinzhou People’s Hospital, Ningbo, China
| | - Yuemin Kuang
- Department of Hematology, Jinhua People’s Hospital, Jinhua, China
| | - Lihong Shou
- Department of Hematology, Huzhou Central Hospital, Huzhou, China
| | - Weimei Jin
- Department of Hematology, Lishui People’s Hospital, Lishui, China
| | - Jianping Lan
- Department of Hematology, Zhejiang Provincial People’s Hospital, Hangzhou, China
| | - Xingnong Ye
- Department of Hematology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China
- Department of Hematology, The Fourth Affiliated Hospital of Zhejiang University, Yiwu, China
| | - Jing Le
- Department of Hematology, Ningbo Lihuili Hospital, Ningbo, China
| | - Huyi Lei
- Department of Hematology, The Affiliated Hospital of Shaoxing University of Arts and Sciences, Shaoxing, China
| | - Jiaping Fu
- Department of Hematology, Shaoxing People’s Hospital, Shaoxing, China
| | - Ying Lin
- Department of Hematology, The Second Affiliated Hospital of Wenzhou University, Wenzhou, China
| | - Wenhua Jiang
- Department of Hematology, Taizhou First People’s Hospital, Taizhou, China
| | - Zhiying Zheng
- Department of Hematology, Zhejiang Provincial Hospital of Chinese Medicine, Hangzhou, China
| | - Songfu Jiang
- Department of Hematology, The First Affiliated Hospital of Wenzhou University, Wenzhou, China
| | - Lijuan Fu
- Department of Hematology, Xinhua Hospital of Zhejiang Province, Hangzhou, China
| | - Chuanyong Su
- Department of Hematology, Tongde Hospital of Zhejiang Province, Hangzhou, China
| | - XiuFeng Yin
- Department of Hematology, The Affiliated Shaoyifu Hospital of Zhejiang University, Hangzhou, China
| | - Lixia Liu
- Department of Medical Affairs, Acornmed Biotechnology Co., Ltd., Tianjin, China
| | - Jiayue Qin
- Department of Medical Affairs, Acornmed Biotechnology Co., Ltd., Tianjin, China
| | - Jie Jin
- Department of Hematology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Shenxian Qian
- Department of Hematology, Hangzhou First People’s Hospital, Hangzhou, China
- *Correspondence: Hongyan Tong, ; Guifang Ouyang, ; Shenxian Qian,
| | - Guifang Ouyang
- Department of Hematology, Ningbo First Hospital, Ningbo, China
- *Correspondence: Hongyan Tong, ; Guifang Ouyang, ; Shenxian Qian,
| | - Hongyan Tong
- Department of Hematology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China
- *Correspondence: Hongyan Tong, ; Guifang Ouyang, ; Shenxian Qian,
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14
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González-Blanco G, García-Rivera G, Talmás-Rohana P, Orozco E, Galindo-Rosales JM, Vélez C, Salucedo-Cárdenas O, Azuara-Liceaga E, Rodríguez-Rodríguez MA, Nozaki T, Valdés J. An Unusual U2AF2 Inhibits Splicing and Attenuates the Virulence of the Human Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2022; 12:888428. [PMID: 35782149 PMCID: PMC9247205 DOI: 10.3389/fcimb.2022.888428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/05/2022] [Indexed: 11/30/2022] Open
Abstract
E. histolytica is the etiological agent of intestinal amebiasis and liver abscesses, which still poses public health threat globally. Metronidazole is the drug of choice against amebiasis. However, metronidazole-resistant amoebic clinical isolates and strains have been reported recently, challenging the efforts for amebiasis eradication. In search of alternative treatments, E. histolytica transcriptomes have shown the association of genes involved in RNA metabolism with the virulence of the parasite. Among the upregulated genes in amoebic liver abscesses are the splicing factors EhU2AF2 and a paralog of EhSF3B1. For this reason and because EhU2AF2 contains unusual KH-QUA2 (84KQ) motifs in its lengthened C-terminus domain, here we investigated how the role of EhU2AF2 in pre-mRNA processing impacts the virulence of the parasite. We found that 84KQ is involved in splicing inhibition/intron retention of several virulence and non-virulence-related genes. The 84KQ domain interacts with the same domain of the constitutive splicing factor SF1 (SF1KQ), both in solution and when SF1KQ is bound to branchpoint signal RNA probes. The 84KQ–SF1KQ interaction prevents splicing complex E to A transition, thus inhibiting splicing. Surprisingly, the deletion of the 84KQ domain in EhU2AF2 amoeba transformants increased splicing and enhanced the in vitro and in vivo virulence phenotypes. We conclude that the interaction of the 84KQ and SF1KQ domains, probably involving additional factors, tunes down Entamoeba virulence by favoring intron retention.
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Affiliation(s)
- Gretter González-Blanco
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
| | - Guillermina García-Rivera
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
| | - Patricia Talmás-Rohana
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
| | - Ester Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
| | - José Manuel Galindo-Rosales
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
| | - Cristina Vélez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
| | - Odila Salucedo-Cárdenas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico
| | - Elisa Azuara-Liceaga
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, CDMX, Mexico
| | - Mario Alberto Rodríguez-Rodríguez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
| | - Tomoyoshi Nozaki
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Jesús Valdés
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), CDMX, Mexico
- *Correspondence: Jesús Valdés,
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15
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Stanley RF, Abdel-Wahab O. Dysregulation and therapeutic targeting of RNA splicing in cancer. NATURE CANCER 2022; 3:536-546. [PMID: 35624337 PMCID: PMC9551392 DOI: 10.1038/s43018-022-00384-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 04/22/2022] [Indexed: 05/15/2023]
Abstract
High-throughput sequencing and functional characterization of the cancer transcriptome have uncovered cancer-specific dysregulation of RNA splicing across a variety of cancers. Alterations in the cancer genome and dysregulation of RNA splicing factors lead to missplicing, splicing alteration-dependent gene expression and, in some cases, generation of novel splicing-derived proteins. Here, we review recent advances in our understanding of aberrant splicing in cancer pathogenesis and present strategies to harness cancer-specific aberrant splicing for therapeutic intent.
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Affiliation(s)
- Robert F Stanley
- Human Oncology and Pathogenesis Program and Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program and Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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16
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Sette C, Paronetto MP. Somatic Mutations in Core Spliceosome Components Promote Tumorigenesis and Generate an Exploitable Vulnerability in Human Cancer. Cancers (Basel) 2022; 14:cancers14071827. [PMID: 35406598 PMCID: PMC8997811 DOI: 10.3390/cancers14071827] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 12/02/2022] Open
Abstract
Simple Summary High throughput exome sequencing approaches have disclosed recurrent cancer-associated mutations in spliceosomal components, which drive aberrant pre-mRNA processing events and support the tumor phenotype. At the same time, mutations in spliceosome genes and aberrant splicing regulation establish a selective vulnerability of cancer cells to splicing-targeting approaches, which could be exploited therapeutically. It is conceivable that a better understanding of the mechanisms and roles of abnormal splicing in tumor metabolism will facilitate the development of a novel generation of tumor-targeting drugs. In this review, we describe recent advances in the elucidation of the biological impact and biochemical effects of somatic mutations in core spliceosome components on splicing choices and their associated targetable vulnerabilities. Abstract Alternative pre-mRNA processing enables the production of distinct mRNA and protein isoforms from a single gene, thus greatly expanding the coding potential of eukaryotic genomes and fine-tuning gene expression programs. Splicing is carried out by the spliceosome, a complex molecular machinery which assembles step-wise on mRNA precursors in the nucleus of eukaryotic cells. In the last decade, exome sequencing technologies have allowed the identification of point mutations in genes encoding splicing factors as a recurrent hallmark of human cancers, with higher incidence in hematological malignancies. These mutations lead to production of splicing factors that reduce the fidelity of the splicing process and yield splicing variants that are often advantageous for cancer cells. However, at the same time, these mutations increase the sensitivity of transformed cells to splicing inhibitors, thus offering a therapeutic opportunity for novel targeted strategies. Herein, we review the recent literature documenting cancer-associated mutations in components of the early spliceosome complex and discuss novel therapeutic strategies based on small-molecule spliceosome inhibitors that exhibit strong anti-tumor effects, particularly against cancer cells harboring mutations in spliceosomal components.
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Affiliation(s)
- Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy;
- GSTEP-Organoids Core Facility, Fondazione Policlinico Agostino Gemelli IRCCS, 00168 Rome, Italy
| | - Maria Paola Paronetto
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Piazza Lauro De Bosis, 6, 00135 Rome, Italy
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, IRCCS, Via del Fosso di Fiorano 64, 00143 Rome, Italy
- Correspondence:
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17
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Niño CA, Scotto di Perrotolo R, Polo S. Recurrent Spliceosome Mutations in Cancer: Mechanisms and Consequences of Aberrant Splice Site Selection. Cancers (Basel) 2022; 14:281. [PMID: 35053445 PMCID: PMC8773931 DOI: 10.3390/cancers14020281] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/30/2021] [Accepted: 01/04/2022] [Indexed: 12/21/2022] Open
Abstract
Splicing alterations have been widely documented in tumors where the proliferation and dissemination of cancer cells is supported by the expression of aberrant isoform variants. Splicing is catalyzed by the spliceosome, a ribonucleoprotein complex that orchestrates the complex process of intron removal and exon ligation. In recent years, recurrent hotspot mutations in the spliceosome components U1 snRNA, SF3B1, and U2AF1 have been identified across different tumor types. Such mutations in principle are highly detrimental for cells as all three spliceosome components are crucial for accurate splice site selection: the U1 snRNA is essential for 5′ splice site recognition, and SF3B1 and U2AF1 are important for 3′ splice site selection. Nonetheless, they appear to be selected to promote specific types of cancers. Here, we review the current molecular understanding of these mutations in cancer, focusing on how they influence splice site selection and impact on cancer development.
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Affiliation(s)
- Carlos A. Niño
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy;
| | | | - Simona Polo
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy;
- Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, 20122 Milan, Italy
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18
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Zou X, Schaefke B, Li Y, Jia F, Sun W, Li G, Liang W, Reif T, Heyd F, Gao Q, Tian S, Li Y, Tang Y, Fang L, Hu Y, Chen W. Mammalian splicing divergence is shaped by drift, buffering in trans, and a scaling law. Life Sci Alliance 2022; 5:5/4/e202101333. [PMID: 34969779 PMCID: PMC8739531 DOI: 10.26508/lsa.202101333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 11/24/2022] Open
Abstract
This study globally investigates the allelic splicing pattern in multiple tissues of an F1 hybrid mouse and reveals the underlying driving forces shaping such tissue-dependent splicing divergence. Alternative splicing is ubiquitous, but the mechanisms underlying its pattern of evolutionary divergence across mammalian tissues are still underexplored. Here, we investigated the cis-regulatory divergences and their relationship with tissue-dependent trans-regulation in multiple tissues of an F1 hybrid between two mouse species. Large splicing changes between tissues are highly conserved and likely reflect functional tissue-dependent regulation. In particular, micro-exons frequently exhibit this pattern with high inclusion levels in the brain. Cis-divergence of splicing appears to be largely non-adaptive. Although divergence is in general associated with higher densities of sequence variants in regulatory regions, events with high usage of the dominant isoform apparently tolerate more mutations, explaining why their exon sequences are highly conserved but their intronic splicing site flanking regions are not. Moreover, we demonstrate that non-adaptive mutations are often masked in tissues where accurate splicing likely is more important, and experimentally attribute such buffering effect to trans-regulatory splicing efficiency.
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Affiliation(s)
- Xudong Zou
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Bernhard Schaefke
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, China
| | - Yisheng Li
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Fujian Jia
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Wei Sun
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Guipeng Li
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, China
| | - Weizheng Liang
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Tristan Reif
- Institute for Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Florian Heyd
- Institute for Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Qingsong Gao
- Laboratory for Systems Biology and Functional Genomics, Berlin Institute for Medical Systems Biology, Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - Shuye Tian
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Yanping Li
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Yisen Tang
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Liang Fang
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, China
| | - Yuhui Hu
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Wei Chen
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China .,Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, China
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19
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Karbstein K. Attacking a DEAD problem: The role of DEAD-box ATPases in ribosome assembly and beyond. Methods Enzymol 2022; 673:19-38. [PMID: 35965007 PMCID: PMC10154911 DOI: 10.1016/bs.mie.2022.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DEAD-box proteins are a subfamily of ATPases with similarity to RecA-type helicases that are involved in all aspects of RNA Biology. Despite their potential to regulate these processes via their RNA-dependent ATPase activity, their roles remain poorly characterized. Here I describe a roadmap to study these proteins in the context of ribosome assembly, the process that utilizes more than half of all DEAD-box proteins encoded in the yeast genome.
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Affiliation(s)
- Katrin Karbstein
- Department of Integrative Structural and Computational Biology, Scripps Florida, Jupiter, FL, United States; HHMI Faculty Scholar, Chevy Chase, MD, United States; The Skaggs Graduate School of Chemical and Biological Sciences, Scripps Florida, Jupiter, FL, United States.
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20
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Yu NK, McClatchy DB, Diedrich JK, Romero S, Choi JH, Martínez-Bartolomé S, Delahunty CM, Muotri AR, Yates JR. Interactome analysis illustrates diverse gene regulatory processes associated with LIN28A in human iPS cell-derived neural progenitor cells. iScience 2021; 24:103321. [PMID: 34816099 PMCID: PMC8593586 DOI: 10.1016/j.isci.2021.103321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/07/2021] [Accepted: 10/19/2021] [Indexed: 12/02/2022] Open
Abstract
A single protein can be multifaceted depending on the cellular contexts and interacting molecules. LIN28A is an RNA-binding protein that governs developmental timing, cellular proliferation, differentiation, stem cell pluripotency, and metabolism. In addition to its best-known roles in microRNA biogenesis, diverse molecular roles have been recognized. In the nervous system, LIN28A is known to play critical roles in proliferation and differentiation of neural progenitor cells (NPCs). We profiled the endogenous LIN28A-interacting proteins in NPCs differentiated from human induced pluripotent stem (iPS) cells using immunoprecipitation and liquid chromatography-tandem mass spectrometry. We identified over 500 LIN28A-interacting proteins, including 156 RNA-independent interactors. Functions of these proteins span a wide range of gene regulatory processes. Prompted by the interactome data, we revealed that LIN28A may impact the subcellular distribution of its interactors and stress granule formation upon oxidative stress. Overall, our analysis opens multiple avenues for elaborating molecular roles and characteristics of LIN28A.
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Affiliation(s)
- Nam-Kyung Yu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Daniel B. McClatchy
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jolene K. Diedrich
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sarah Romero
- Department of Pediatrics/Rady Children’s Hospital San Diego, Department of Cellular & Molecular Medicine, School of Medicine, University of California, San Diego, San Diego, CA 92037, USA
| | - Jun-Hyeok Choi
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Claire M. Delahunty
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Alysson R. Muotri
- Department of Pediatrics/Rady Children’s Hospital San Diego, Department of Cellular & Molecular Medicine, School of Medicine, University of California, San Diego, San Diego, CA 92037, USA
- Stem Cell Program, Center for Academic Research and Training in Anthropogeny (CARTA), Archealization Center (ArchC), Kavli Institute for Brain and Mind, La Jolla, CA 92037, USA
| | - John R. Yates
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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21
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Borao S, Ayté J, Hümmer S. Evolution of the Early Spliceosomal Complex-From Constitutive to Regulated Splicing. Int J Mol Sci 2021; 22:ijms222212444. [PMID: 34830325 PMCID: PMC8624252 DOI: 10.3390/ijms222212444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 12/14/2022] Open
Abstract
Pre-mRNA splicing is a major process in the regulated expression of genes in eukaryotes, and alternative splicing is used to generate different proteins from the same coding gene. Splicing is a catalytic process that removes introns and ligates exons to create the RNA sequence that codifies the final protein. While this is achieved in an autocatalytic process in ancestral group II introns in prokaryotes, the spliceosome has evolved during eukaryogenesis to assist in this process and to finally provide the opportunity for intron-specific splicing. In the early stage of splicing, the RNA 5' and 3' splice sites must be brought within proximity to correctly assemble the active spliceosome and perform the excision and ligation reactions. The assembly of this first complex, termed E-complex, is currently the least understood process. We focused in this review on the formation of the E-complex and compared its composition and function in three different organisms. We highlight the common ancestral mechanisms in S. cerevisiae, S. pombe, and mammals and conclude with a unifying model for intron definition in constitutive and regulated co-transcriptional splicing.
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Affiliation(s)
- Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Correspondence: (J.A.); (S.H.)
| | - Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Translational Molecular Pathology, Vall d’Hebron Research Institute (VHIR), CIBERONC, 08035 Barcelona, Spain
- Correspondence: (J.A.); (S.H.)
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22
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Zhang B, Ding Z, Li L, Xie LK, Fan YJ, Xu YZ. Two oppositely-charged sf3b1 mutations cause defective development, impaired immune response, and aberrant selection of intronic branch sites in Drosophila. PLoS Genet 2021; 17:e1009861. [PMID: 34723968 PMCID: PMC8559932 DOI: 10.1371/journal.pgen.1009861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 10/06/2021] [Indexed: 11/18/2022] Open
Abstract
SF3B1 mutations occur in many cancers, and the highly conserved His662 residue is one of the hotspot mutation sites. To address effects on splicing and development, we constructed strains carrying point mutations at the corresponding residue His698 in Drosophila using the CRISPR-Cas9 technique. Two mutations, H698D and H698R, were selected due to their frequent presence in patients and notable opposite charges. Both the sf3b1-H698D and–H698R mutant flies exhibit developmental defects, including less egg-laying, decreased hatching rates, delayed morphogenesis and shorter lifespans. Interestingly, the H698D mutant has decreased resistance to fungal infection, while the H698R mutant shows impaired climbing ability. Consistent with these phenotypes, further analysis of RNA-seq data finds altered expression of immune response genes and changed alternative splicing of muscle and neural-related genes in the two mutants, respectively. Expression of Mef2-RB, an isoform of Mef2 gene that was downregulated due to splicing changes caused by H698R, partly rescues the climbing defects of the sf3b1-H698R mutant. Lariat sequencing reveals that the two sf3b1-H698 mutations cause aberrant selection of multiple intronic branch sites, with the H698R mutant using far upstream branch sites in the changed alternative splicing events. This study provides in vivo evidence from Drosophila that elucidates how these SF3B1 hotspot mutations alter splicing and their consequences in development and in the immune system. In the past decade, one of the important findings in the RNA splicing field has been that somatic SF3B1 mutations widely occur in many cancers. Including R625, H662, K666, K700 and E902, there are five hotspot mutation sites in the highly conserved HEAT repeats of SF3B1. Several kinds of H662 mutations have been found widely in MDS, AML, CLL and breast cancers; however, it remains unclear how these H662 mutations alter splicing and whether they have in vivo effects on development. To address these questions, in this manuscript, we first summarized the H662 mutations in human diseases and constructed two corresponding Drosophila mutant strains, sf3b1-H698D and -H698R using CRISPR-Cas9. Analyses of these two fly strains find that the two oppositely charged Sf3b1-H698 mutants are defective in development. In addition, one mutant has decreased climbing ability, whereas the other mutant has impaired immune response. Further RNA-seq allows us to find responsible genes in each mutant strain, and lariat sequencing reveals that both mutations cause aberrant selection of the intronic branch sites. Our findings provide the first in vivo evidence that Sf3b1 mutations result in defective development, and also reveal a molecular mechanism of these hotspot histidine mutations that enhance the use of cryptic branch sites to alter splicing. Importantly, we demonstrate that the H698R mutant prefers to use far upstream branch sites.
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Affiliation(s)
- Bei Zhang
- University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences; Shanghai, China
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Hubei, China
| | - Zhan Ding
- University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences; Shanghai, China
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Hubei, China
| | - Liang Li
- University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences; Shanghai, China
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Hubei, China
| | - Ling-Kun Xie
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Hubei, China
| | - Yu-Jie Fan
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Hubei, China
| | - Yong-Zhen Xu
- RNA Institute, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Hubei, China
- * E-mail:
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23
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Hümmer S, Borao S, Guerra-Moreno A, Cozzuto L, Hidalgo E, Ayté J. Cross talk between the upstream exon-intron junction and Prp2 facilitates splicing of non-consensus introns. Cell Rep 2021; 37:109893. [PMID: 34706246 DOI: 10.1016/j.celrep.2021.109893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 04/27/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022] Open
Abstract
Splicing of mRNA precursors is essential in the regulation of gene expression. U2AF65 recognizes the poly-pyrimidine tract and helps in the recognition of the branch point. Inactivation of fission yeast U2AF65 (Prp2) blocks splicing of most, but not all, pre-mRNAs, for reasons that are not understood. Here, we have determined genome-wide the splicing efficiency of fission yeast cells as they progress into synchronous meiosis in the presence or absence of functional Prp2. Our data indicate that in addition to the splicing elements at the 3' end of any intron, the nucleotides immediately upstream the intron will determine whether Prp2 is required or dispensable for splicing. By changing those nucleotides in any given intron, we regulate its Prp2 dependency. Our results suggest a model in which Prp2 is required for the coordinated recognition of both intronic ends, placing Prp2 as a key regulatory element in the determination of the exon-intron boundaries.
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Affiliation(s)
- Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
| | - Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Angel Guerra-Moreno
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Luca Cozzuto
- CRG Bioinformatics Core, Centre de Regulació Genòmica (CRG), 08003 Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
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24
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Abstract
Herculean efforts by the Wellcome Sanger Institute, the National Cancer Institute, and the National Human Genome Research Institute to sequence thousands of tumors representing all major cancer types have yielded more than 700 genes that contribute to neoplastic growth when mutated, amplified, or deleted. While some of these genes (now included in the COSMIC Cancer Gene Census) encode proteins previously identified in hypothesis-driven experiments (oncogenic transcription factors, protein kinases, etc.), additional classes of cancer drivers have emerged, perhaps none more surprisingly than RNA-binding proteins (RBPs). Over 40 RBPs responsible for virtually all aspects of RNA metabolism, from synthesis to degradation, are recurrently mutated in cancer, and just over a dozen are considered major cancer drivers. This Review investigates whether and how their RNA-binding activities pertain to their oncogenic functions. Focusing on several well-characterized steps in RNA metabolism, we demonstrate that for virtually all cancer-driving RBPs, RNA processing activities are either abolished (the loss-of-function phenotype) or carried out with low fidelity (the LoFi phenotype). Conceptually, this suggests that in normal cells, RBPs act as gatekeepers maintaining proper RNA metabolism and the "balanced" proteome. From the practical standpoint, at least some LoFi phenotypes create therapeutic vulnerabilities, which are beginning to be exploited in the clinic.
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25
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Kobayashi A, Clément MJ, Craveur P, El Hage K, Salone JDM, Bollot G, Pastré D, Maucuer A. Identification of a small molecule splicing inhibitor targeting UHM domains. FEBS J 2021; 289:682-698. [PMID: 34520118 DOI: 10.1111/febs.16199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/10/2021] [Accepted: 09/13/2021] [Indexed: 01/07/2023]
Abstract
Splicing factor mutations are frequent in myeloid neoplasms, blood cancers, and solid tumors. Cancer cells harboring these mutations present a particular vulnerability to drugs that target splicing factors such as SF3b155 or CAPERα. Still, the arsenal of chemical probes that target the spliceosome is very limited. U2AF homology motifs (UHMs) are common protein interaction domains among splicing factors. They present a hydrophobic pocket ideally suited to anchor small molecules with the aim to inhibit protein-protein interaction. Here, we combined a virtual screening of a small molecules database and an in vitro competition assay and identified a small molecule, we named UHMCP1 that prevents the SF3b155/U2AF65 interaction. NMR analyses and molecular dynamics simulations confirmed the binding of this molecule in the hydrophobic pocket of the U2AF65 UHM domain. We further provide evidence that UHMCP1 impacts RNA splicing and cell viability and is therefore an interesting novel compound targeting an UHM domain with potential anticancer properties.
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Affiliation(s)
- Asaki Kobayashi
- SABNP, Univ Evry, INSERM U1204, Université Paris-Saclay, Evry, France.,SYNSIGHT, Genopole Entreprises, Evry, France
| | | | | | - Krystel El Hage
- SABNP, Univ Evry, INSERM U1204, Université Paris-Saclay, Evry, France
| | | | | | - David Pastré
- SABNP, Univ Evry, INSERM U1204, Université Paris-Saclay, Evry, France
| | - Alexandre Maucuer
- SABNP, Univ Evry, INSERM U1204, Université Paris-Saclay, Evry, France
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26
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Kao CY, Cao EC, Wai HL, Cheng SC. Evidence for complex dynamics during U2 snRNP selection of the intron branchpoint. Nucleic Acids Res 2021; 49:9965-9977. [PMID: 34387687 PMCID: PMC8464032 DOI: 10.1093/nar/gkab695] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/27/2021] [Accepted: 08/11/2021] [Indexed: 12/16/2022] Open
Abstract
Splicing of pre-mRNA is initiated by binding of U1 to the 5′ splice site and of Msl5-Mud2 heterodimer to the branch site (BS). Subsequent binding of U2 displaces Msl5-Mud2 from the BS to form the prespliceosome, a step governing branchpoint selection and hence 3′ splice site choice, and linking splicing to myelodysplasia and many cancers in human. Two DEAD-box proteins, Prp5 and Sub2, are required for this step, but neither is stably associated with the pre-mRNA during the reaction. Using BS-mutated ACT1 pre-mRNA, we previously identified a splicing intermediate complex, FIC, which contains U2 and Prp5, but cannot bind the tri-snRNP. We show here that Msl5 remains associated with the upstream cryptic branch site (CBS) in the FIC, with U2 binding a few bases downstream of the BS. U2 mutants that restore U2-BS base pairing enable dissociation of Prp5 and allows splicing to proceed. The CBS is required for splicing rescue by compensatory U2 mutants, and for formation of FIC, demonstrating a role for Msl5 in directing U2 to the BS, and of U2-BS base pairing for release of Prp5 and Msl5-Mud2 to form the prespliceosome. Our results provide insights into how the prespliceosome may form in normal splicing reaction.
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Affiliation(s)
- Ching-Yang Kao
- Genome and Systems Biology Degree Program, National Taiwan University, Taipei, Taiwan 106, Republic of China.,Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
| | - En-Cih Cao
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
| | - Hsu Lei Wai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
| | - Soo-Chen Cheng
- Genome and Systems Biology Degree Program, National Taiwan University, Taipei, Taiwan 106, Republic of China.,Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China
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27
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Abstract
PURPOSE OF REVIEW Splicing mutations are among the most recurrent genetic perturbations in hematological malignancies, highlighting an important impact of splicing regulation in hematopoietic development. However, compared to our understanding of splicing factor mutations in hematological malignancies, studies of splicing components and alternative splicing in normal hematopoiesis have been less well investigated. Here, we outline the most recent findings on splicing regulation in normal hematopoiesis and discuss the important questions in the field. RECENT FINDINGS Recent studies have highlighted the critical role of splicing regulation in hematopoiesis, including characterization of splicing components in normal hematopoiesis, investigation of transcriptional alterations on splicing, and identification of stage-specific alternative splicing events during hematopoietic development. SUMMARY These interesting findings provide insights on hematopoietic regulation at a co-transcriptional level. More high-throughput RNA ribonucleic acid (RNA) sequencing and functional genomic screens are needed to advance our knowledge of critical alternative splicing patterns in shaping hematopoiesis.
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Affiliation(s)
- Sisi Chen
- Human Oncology and Pathogenesis Program, Dept. of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Dept. of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065
- Leukemia Service, Dept. of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065
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28
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Splicing factor mutations in hematologic malignancies. Blood 2021; 138:599-612. [PMID: 34157091 DOI: 10.1182/blood.2019004260] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/02/2020] [Indexed: 12/15/2022] Open
Abstract
Mutations in genes encoding RNA splicing factors were discovered nearly ten years ago and are now understood to be amongst the most recurrent genetic abnormalities in patients with all forms of myeloid neoplasms and several types of lymphoproliferative disorders as well as subjects with clonal hematopoiesis. These discoveries implicate aberrant RNA splicing, the process by which precursor RNA is converted into mature messenger RNA, in the development of clonal hematopoietic conditions. Both the protein as well as the RNA components of the splicing machinery are affected by mutations at highly specific residues and a number of these mutations alter splicing in a manner distinct from loss of function. Importantly, cells bearing these mutations have now been shown to generate mRNA species with novel aberrant sequences, some of which may be critical to disease pathogenesis and/or novel targets for therapy. These findings have opened new avenues of research to understand biological pathways disrupted by altered splicing. In parallel, multiple studies have revealed that cells bearing change-of-function mutation in splicing factors are preferentially sensitized to any further genetic or chemical perturbations of the splicing machinery. These discoveries are now being pursued in several early phase clinical trials using molecules with diverse mechanisms of action. Here we review the molecular effects of splicing factor mutations on splicing, mechanisms by which these mutations drive clonal transformation of hematopoietic cells, and the development of new therapeutics targeting these genetic subsets of hematopoietic malignancies.
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29
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Martelly W, Fellows B, Kang P, Vashisht A, Wohlschlegel JA, Sharma S. Synergistic roles for human U1 snRNA stem-loops in pre-mRNA splicing. RNA Biol 2021; 18:2576-2593. [PMID: 34105434 DOI: 10.1080/15476286.2021.1932360] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
During spliceosome assembly, interactions that bring the 5' and 3' ends of an intron in proximity are critical for the production of mature mRNA. Here, we report synergistic roles for the stem-loops 3 (SL3) and 4 (SL4) of the human U1 small nuclear RNA (snRNA) in maintaining the optimal U1 snRNP function, and formation of cross-intron contact with the U2 snRNP. We find that SL3 and SL4 bind distinct spliceosomal proteins and combining a U1 snRNA activity assay with siRNA-mediated knockdown, we demonstrate that SL3 and SL4 act through the RNA helicase UAP56 and the U2 protein SF3A1, respectively. In vitro analysis using UV crosslinking and splicing assays indicated that SL3 likely promotes the SL4-SF3A1 interaction leading to enhancement of A complex formation and pre-mRNA splicing. Overall, these results highlight the vital role of the distinct contacts of SL3 and SL4 in bridging the pre-mRNA bound U1 and U2 snRNPs during the early steps of human spliceosome assembly.
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Affiliation(s)
- William Martelly
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ, USA.,School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Bernice Fellows
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Paul Kang
- Department of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health-Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Ajay Vashisht
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Shalini Sharma
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ, USA
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30
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Butt H, Bazin J, Alshareef S, Eid A, Benhamed M, Reddy ASN, Crespi M, Mahfouz MM. Overlapping roles of spliceosomal components SF3B1 and PHF5A in rice splicing regulation. Commun Biol 2021; 4:529. [PMID: 33953336 PMCID: PMC8100303 DOI: 10.1038/s42003-021-02051-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/26/2021] [Indexed: 01/02/2023] Open
Abstract
The SF3B complex, a multiprotein component of the U2 snRNP of the spliceosome, plays a crucial role in recognizing branch point sequence and facilitates spliceosome assembly and activation. Several chemicals that bind SF3B1 and PHF5A subunits of the SF3B complex inhibit splicing. We recently generated a splicing inhibitor-resistant SF3B1 mutant named SF3B1GEX1ARESISTANT 4 (SGR4) using CRISPR-mediated directed evolution, whereas splicing inhibitor-resistant mutant of PHF5A (Overexpression-PHF5A GEX1A Resistance, OGR) was generated by expressing an engineered version PHF5A-Y36C. Global analysis of splicing in wild type and these two mutants revealed the role of SF3B1 and PHF5A in splicing regulation. This analysis uncovered a set of genes whose intron retention is regulated by both proteins. Further analysis of these retained introns revealed that they are shorter, have a higher GC content, and contain shorter and weaker polypyrimidine tracts. Furthermore, splicing inhibition increased seedlings sensitivity to salt stress, consistent with emerging roles of splicing regulation in stress responses. In summary, we uncovered the functions of two members of the plant branch point recognition complex. The novel strategies described here should be broadly applicable in elucidating functions of splicing regulators, especially in studying the functions of redundant paralogs in plants. Butt et al. used CRISPR-mediated directed evolution to generate rice mutants for the spliceosome components SF3B1 and PHF5A. They demonstrate that these mutants have different levels of sensitivity to salt treatments and suggest that the strategies they employed can be used in the future to study functions of redundant paralogs in plants.
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Affiliation(s)
- Haroon Butt
- Laboratory for Genome Engineering and Synthetic Biology, King Abdullah, University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Jeremie Bazin
- CNRS, INRA, Institute of Plant Sciences Paris-Saclay IPS2, Univ Paris Sud, Univ Evry, Univ Paris-Diderot, Sorbonne Paris-Cite, Universite Paris-Saclay, Orsay, France
| | - Sahar Alshareef
- Laboratory for Genome Engineering and Synthetic Biology, King Abdullah, University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Ayman Eid
- Laboratory for Genome Engineering and Synthetic Biology, King Abdullah, University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Moussa Benhamed
- CNRS, INRA, Institute of Plant Sciences Paris-Saclay IPS2, Univ Paris Sud, Univ Evry, Univ Paris-Diderot, Sorbonne Paris-Cite, Universite Paris-Saclay, Orsay, France
| | - Anireddy S N Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Martin Crespi
- CNRS, INRA, Institute of Plant Sciences Paris-Saclay IPS2, Univ Paris Sud, Univ Evry, Univ Paris-Diderot, Sorbonne Paris-Cite, Universite Paris-Saclay, Orsay, France
| | - Magdy M Mahfouz
- Laboratory for Genome Engineering and Synthetic Biology, King Abdullah, University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
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Caizzi L, Monteiro-Martins S, Schwalb B, Lysakovskaia K, Schmitzova J, Sawicka A, Chen Y, Lidschreiber M, Cramer P. Efficient RNA polymerase II pause release requires U2 snRNP function. Mol Cell 2021; 81:1920-1934.e9. [PMID: 33689748 DOI: 10.1016/j.molcel.2021.02.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 01/07/2021] [Accepted: 02/10/2021] [Indexed: 12/21/2022]
Abstract
Transcription by RNA polymerase II (Pol II) is coupled to pre-mRNA splicing, but the underlying mechanisms remain poorly understood. Co-transcriptional splicing requires assembly of a functional spliceosome on nascent pre-mRNA, but whether and how this influences Pol II transcription remains unclear. Here we show that inhibition of pre-mRNA branch site recognition by the spliceosome component U2 snRNP leads to a widespread and strong decrease in new RNA synthesis from human genes. Multiomics analysis reveals that inhibition of U2 snRNP function increases the duration of Pol II pausing in the promoter-proximal region, impairs recruitment of the pause release factor P-TEFb, and reduces Pol II elongation velocity at the beginning of genes. Our results indicate that efficient release of paused Pol II into active transcription elongation requires the formation of functional spliceosomes and that eukaryotic mRNA biogenesis relies on positive feedback from the splicing machinery to the transcription machinery.
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Affiliation(s)
- Livia Caizzi
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Sara Monteiro-Martins
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Björn Schwalb
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Kseniia Lysakovskaia
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Jana Schmitzova
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Anna Sawicka
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ying Chen
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Michael Lidschreiber
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
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32
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Li Z, Zhao B, Shi Y, Liang Y, Qian R, Wan Y. Characterization of the aberrant splicing of MAP3K7 induced by cancer-associated SF3B1 mutation. J Biochem 2021; 170:69-77. [PMID: 33751071 DOI: 10.1093/jb/mvab023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 02/24/2021] [Indexed: 11/12/2022] Open
Abstract
SF3B1, an essential RNA splicing factor, is frequently mutated in various types of cancers, and the cancer-associated SF3B1 mutation causes aberrant RNA splicing. The aberrant splicing of several transcripts, including MAP3K7, promotes tumorigenesis. Here, we identify a premature termination codon in the aberrantly spliced transcript of MAP3K7. Treatment of HEK293T cells transfected with the K700E-mutated SF3B1 with cycloheximide leads to increased accumulation of the aberrant spliced transcript of MAP3K7, demonstrating that the aberrantly spliced transcript of MAP3K7 is targeted by nonsense-mediated decay. The aberrantly spliced MAP3K7 transcript uses an aberrant 3' splice sites and an alternative branchpoint sequence. In addition, the aberrant splicing of MAP3K7 requires not only the polypyrimidine tract associated with normal splicing but also an alternative polypyrimidine tract upstream of the aberrant 3' splice site. Other cancer-associated SF3B1 mutations also cause the aberrant splicing of MAP3K7, which depends on the same sequence features. Our data provide a further understanding of the mechanisms underlying aberrant splicing induced by cancer-associated SF3B1 mutation, and reveal an important role of alternative polypyrimidine tract in diseases.
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Affiliation(s)
- Zhuang Li
- China-Japan Union Hospital of Jilin University, Jilin University, Changchun, Jilin, 130033, China.,School of Life Sciences, Jilin University, Changchun, Jilin, 130012, China
| | - Bo Zhao
- China-Japan Union Hospital of Jilin University, Jilin University, Changchun, Jilin, 130033, China.,School of Life Sciences, Jilin University, Changchun, Jilin, 130012, China
| | - Yueru Shi
- China-Japan Union Hospital of Jilin University, Jilin University, Changchun, Jilin, 130033, China.,School of Life Sciences, Jilin University, Changchun, Jilin, 130012, China
| | - Yuqi Liang
- School of Life Sciences, Jilin University, Changchun, Jilin, 130012, China
| | - Rui Qian
- China-Japan Union Hospital of Jilin University, Jilin University, Changchun, Jilin, 130033, China.,School of Life Sciences, Jilin University, Changchun, Jilin, 130012, China
| | - Youzhong Wan
- China-Japan Union Hospital of Jilin University, Jilin University, Changchun, Jilin, 130033, China
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Canbezdi C, Tarin M, Houy A, Bellanger D, Popova T, Stern MH, Roman-Roman S, Alsafadi S. Functional and conformational impact of cancer-associated SF3B1 mutations depends on the position and the charge of amino acid substitution. Comput Struct Biotechnol J 2021; 19:1361-1370. [PMID: 33777335 PMCID: PMC7960499 DOI: 10.1016/j.csbj.2021.02.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/13/2021] [Accepted: 02/16/2021] [Indexed: 11/18/2022] Open
Abstract
The hotspot mutations of SF3B1, the most frequently mutated splicing gene in cancers, contribute to oncogenesis by corrupting the mRNA splicing. Further SF3B1 mutations have been reported in cancers but their consequences remain unclear. Here, we screened for SF3B1 mutations in the vicinity of the hotspot region in tumors. We then performed in-silico prediction of the functional outcome followed by in-cellulo modelling of different SF3B1 mutants. We show that cancer-associated SF3B1 mutations present varying functional consequences that are loosely predicted by the in-silico algorithms. Analysis of the tertiary structure of SF3B1 mutants revealed that the resulting splicing errors may be due to a conformational change in SF3B1 N-terminal region, which mediates binding with other splicing factors. Our study demonstrates a varying functional impact of SF3B1 mutations according to the mutated codon and the amino acid substitution, implying unequal pathogenic and prognostic potentials of SF3B1 mutations in cancers.
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Affiliation(s)
- Christine Canbezdi
- Institut Curie, PSL Research University, Uveal Melanoma Group, Translational Research Department, Paris, France
| | - Malcy Tarin
- Institut Curie, PSL Research University, Uveal Melanoma Group, Translational Research Department, Paris, France
| | - Alexandre Houy
- Institut Curie, PSL Research University, INSERM U830, DNA Repair and Uveal Melanoma (D.R.U.M.), Paris, France
| | - Dorine Bellanger
- Institut Curie, PSL Research University, INSERM U830, DNA Repair and Uveal Melanoma (D.R.U.M.), Paris, France
- University of Tours, INSERM UMR1069, Tours, France
| | - Tatiana Popova
- Institut Curie, PSL Research University, INSERM U830, DNA Repair and Uveal Melanoma (D.R.U.M.), Paris, France
| | - Marc-Henri Stern
- Institut Curie, PSL Research University, INSERM U830, DNA Repair and Uveal Melanoma (D.R.U.M.), Paris, France
| | - Sergio Roman-Roman
- Institut Curie, PSL Research University, Uveal Melanoma Group, Translational Research Department, Paris, France
| | - Samar Alsafadi
- Institut Curie, PSL Research University, Uveal Melanoma Group, Translational Research Department, Paris, France
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34
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Characterization of the aberrant splicing of DVL2 induced by cancer-associated SF3B1 mutation. Biochem Biophys Res Commun 2021; 546:21-28. [PMID: 33561744 DOI: 10.1016/j.bbrc.2021.01.084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/26/2021] [Indexed: 11/23/2022]
Abstract
SF3B1, an essential component of the U2 snRNP, is frequently mutated in cancers. Cancer-associated SF3B1 mutation causes aberrant RNA splicing, mostly at 3' splice sites (3'ss). RNA splicing of DVL2, a regulator of Notch signaling, is affected by SF3B1 mutation. Here, we report that the mutated SF3B1 use an alternative branchpoint sequence (BPS) for the aberrant splicing of DVL2, which has a higher affinity to U2 snRNA than the BPS for the canonical splicing of DVL2. Swapping the position of the alternative BPS with the position of the canonical BPS decreased the aberrant splicing of DVL2, suggesting that the mutated SF3B1 prefers to use BPS with high affinity to U2 snRNA for splicing. Additionally, swapping the positions of two BPSs associated with the canonical splicing of DVL2 demonstrated that both the affinity to the U2 snRNA and the distance to the 3'ss are important to the selection of BPS. Importantly, the aberrant splicing of DVL2 does not require the canonical 3'ss and the canonical polypyrimidine tract, which reveals a novel type of aberrant splicing induced by SF3B1 mutation. These findings provide a more comprehensive understanding of the mechanisms underlying aberrant splicing induced by SF3B1 mutation in cancer.
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35
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Larsen NA. The SF3b Complex is an Integral Component of the Spliceosome and Targeted by Natural Product-Based Inhibitors. Subcell Biochem 2021; 96:409-432. [PMID: 33252738 DOI: 10.1007/978-3-030-58971-4_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
In this chapter, the essential role of the SF3b multi-protein complex will be discussed in the context of the overall spliceosome. SF3b is critical during spliceosome assembly for recognition of the branch point (BP) adenosine and, by de facto, selection of the 3' splice site. This complex is highly dynamic, undergoing significant conformational changes upon loading of the branch duplex RNA and in its relative positioning during spliceosomal remodeling from the A, pre-B, B, Bact and B* complexes. Ultimately, during the spliceosome activation phase, SF3b must be displaced to unmask the branch point adenosine for the first splicing reaction to occur. In certain cancers, such as the hematological malignancies CML, CLL and MDS, the SF3b subunit SF3B1 is frequently mutated. Recent studies suggest these mutations lead to inappropriate branch point selection and mis-splicing events that appear to be drivers of disease. Finally, the SF3b complex is the target for at least three different classes of natural product-based inhibitors. These inhibitors bind in the BP adenosine-binding pocket and demonstrate a pre-mRNA competitive mechanism of action resulting in either intron retention or exon skipping. These compounds are extremely useful as chemical probes to isolate and characterize early stages of spliceosome assembly. They are also being explored preclinically and clinically as possible agents for hematological cancers.
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36
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van Poppelen NM, de Bruyn DP, Bicer T, Verdijk R, Naus N, Mensink H, Paridaens D, de Klein A, Brosens E, Kiliҫ E. Genetics of Ocular Melanoma: Insights into Genetics, Inheritance and Testing. Int J Mol Sci 2020; 22:E336. [PMID: 33396957 PMCID: PMC7795687 DOI: 10.3390/ijms22010336] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/04/2020] [Accepted: 12/24/2020] [Indexed: 12/18/2022] Open
Abstract
Ocular melanoma consists of posterior uveal melanoma, iris melanoma and conjunctival melanoma. These malignancies derive from melanocytes in the uveal tract or conjunctiva. The genetic profiles of these different entities differ from each other. In uveal melanoma, GNAQ and GNA11 gene mutations are frequently found and prognosis is based on mutation status of BAP1, SF3B1 and EIF1AX genes. Iris melanoma, also originating from the uvea, has similarities to the genetic makeups of both posterior uveal melanoma (UM) and conjunctival melanoma since mutations in GNAQ and GNA11 are less common and genes involved in conjunctival melanoma such as BRAF have been described. The genetic spectrum of conjunctival melanoma, however, includes frequent mutations in the BRAF, NRAS and TERT promoter genes, which are found in cutaneous melanoma as well. The BRAF status of the tumor is not correlated to prognosis, whereas the TERT promoter gene mutations are. Clinical presentation, histopathological characteristics and copy number alterations are associated with survival in ocular melanoma. Tissue material is needed to classify ocular melanoma in the different subgroups, which creates a need for the use of noninvasive techniques to prognosticate patients who underwent eye preserving treatment.
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Affiliation(s)
- Natasha M. van Poppelen
- Department of Ophthalmology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (N.M.v.P.); (D.P.d.B.); (T.B.); (N.N.); (D.P.)
- Department of Clinical Genetics, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (A.d.K.); (E.B.)
| | - Daniël P. de Bruyn
- Department of Ophthalmology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (N.M.v.P.); (D.P.d.B.); (T.B.); (N.N.); (D.P.)
- Department of Clinical Genetics, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (A.d.K.); (E.B.)
| | - Tolga Bicer
- Department of Ophthalmology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (N.M.v.P.); (D.P.d.B.); (T.B.); (N.N.); (D.P.)
- Department of Ophthalmology, University of Health Sciences Diskapi Training and Research Hospital, Ankara 06330, Turkey
| | - Rob Verdijk
- Department of Pathology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands;
- Department of Pathology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Nicole Naus
- Department of Ophthalmology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (N.M.v.P.); (D.P.d.B.); (T.B.); (N.N.); (D.P.)
| | - Hanneke Mensink
- Department of Ophthalmic Oncology, The Rotterdam Eye Hospital, 3011 BH Rotterdam, The Netherlands;
| | - Dion Paridaens
- Department of Ophthalmology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (N.M.v.P.); (D.P.d.B.); (T.B.); (N.N.); (D.P.)
- Department of Ophthalmic Oncology, The Rotterdam Eye Hospital, 3011 BH Rotterdam, The Netherlands;
| | - Annelies de Klein
- Department of Clinical Genetics, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (A.d.K.); (E.B.)
| | - Erwin Brosens
- Department of Clinical Genetics, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (A.d.K.); (E.B.)
| | - Emine Kiliҫ
- Department of Ophthalmology, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands; (N.M.v.P.); (D.P.d.B.); (T.B.); (N.N.); (D.P.)
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U2AF65-Dependent SF3B1 Function in SMN Alternative Splicing. Cells 2020; 9:cells9122647. [PMID: 33317029 PMCID: PMC7762998 DOI: 10.3390/cells9122647] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/05/2020] [Accepted: 12/07/2020] [Indexed: 11/17/2022] Open
Abstract
Splicing factor 3b subunit 1 (SF3B1) is an essential protein in spliceosomes and mutated frequently in many cancers. While roles of SF3B1 in single intron splicing and roles of its cancer-linked mutant in aberrant splicing have been identified to some extent, regulatory functions of wild-type SF3B1 in alternative splicing (AS) are not well-understood yet. Here, we applied RNA sequencing (RNA-seq) to analyze genome-wide AS in SF3B1 knockdown (KD) cells and to identify a large number of skipped exons (SEs), with a considerable number of alternative 5′ splice-site selection, alternative 3′ splice-site selection, mutually exclusive exons (MXE), and retention of introns (RI). Among altered SEs by SF3B1 KD, survival motor neuron 2 (SMN2) pre-mRNA exon 7 splicing was a regulatory target of SF3B1. RT-PCR analysis of SMN exon 7 splicing in SF3B1 KD or overexpressed HCT116, SH-SY5Y, HEK293T, and spinal muscular atrophy (SMA) patient cells validated the results. A deletion mutation demonstrated that the U2 snRNP auxiliary factor 65 kDa (U2AF65) interaction domain of SF3B1 was required for its function in SMN exon 7 splicing. In addition, mutations to lower the score of the polypyrimidine tract (PPT) of exon 7, resulting in lower affinity for U2AF65, were not able to support SF3B1 function, suggesting the importance of U2AF65 in SF3B1 function. Furthermore, the PPT of exon 7 with higher affinity to U2AF65 than exon 8 showed significantly stronger interactions with SF3B1. Collectively, our results revealed SF3B1 function in SMN alternative splicing.
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38
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Zhang D, Meng F. A Comprehensive Overview of Structure-Activity Relationships of Small-Molecule Splicing Modulators Targeting SF3B1 as Anticancer Agents. ChemMedChem 2020; 15:2098-2120. [PMID: 33037739 DOI: 10.1002/cmdc.202000642] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/19/2020] [Indexed: 02/06/2023]
Abstract
The pre-mRNA splicing factor SF3B1 shows recurrent mutations among hematologic malignancies and some solid tumors. In 2007, the identification of two cytotoxic natural products, which showed splicing inhibition by binding to SF3b, prompted the development of small-molecule splicing modulators of SF3B1 as therapeutics for cancer. Recent studies suggested that spliceosome-mutant cells are preferentially sensitive to pharmacologic splicing modulation; therefore, exploring the clinical utility of splicing modulator therapies in patients with spliceosome-mutant hematologic malignancies who have failed current therapies is greatly needed, as these patients have few treatment options. H3B-8800 had unique pharmacological activity and exhibited favorable data in phase I clinical trials to treat patients with advanced myeloid malignancies, indicating that further clinical trials are promising. The most established small-molecule modulators of SF3B1 can be categorized into three classes: the bicycles, the monopyranes, and the 12-membered macrolides. This review provides a comprehensive overview of the structure-activity relationships of small-molecule SF3B1 modulators, with a detailed analysis of interactions between modulators and protein binding pocket. The future strategy for splicing modulators development is also discussed.
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Affiliation(s)
- Datong Zhang
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), 3501 Daxue Road, Jinan, 250353, P. R. China
| | - Fancui Meng
- Tianjin Institute of Pharmaceutical Research, 306 Huiren Road, Tianjin, 300301, P. R. China
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Zhang KL, Feng Z, Yang JF, Yang F, Yuan T, Zhang D, Hao GF, Fang YM, Zhang J, Wu C, Chen MX, Zhu FY. Systematic characterization of the branch point binding protein, splicing factor 1, gene family in plant development and stress responses. BMC PLANT BIOLOGY 2020; 20:379. [PMID: 32811430 PMCID: PMC7433366 DOI: 10.1186/s12870-020-02570-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/22/2020] [Indexed: 06/01/2023]
Abstract
BACKGROUND Among eukaryotic organisms, alternative splicing is an important process that can generate multiple transcripts from one same precursor messenger RNA, which greatly increase transcriptome and proteome diversity. This process is carried out by a super-protein complex defined as the spliceosome. Specifically, splicing factor 1/branchpoint binding protein (SF1/BBP) is a single protein that can bind to the intronic branchpoint sequence (BPS), connecting the 5' and 3' splice site binding complexes during early spliceosome assembly. The molecular function of this protein has been extensively investigated in yeast, metazoa and mammals. However, its counterpart in plants has been seldomly reported. RESULTS To this end, we conducted a systematic characterization of the SF1 gene family across plant lineages. In this work, a total of 92 sequences from 59 plant species were identified. Phylogenetic relationships of these sequences were constructed, and subsequent bioinformatic analysis suggested that this family likely originated from an ancient gene transposition duplication event. Most plant species were shown to maintain a single copy of this gene. Furthermore, an additional RNA binding motif (RRM) existed in most members of this gene family in comparison to their animal and yeast counterparts, indicating that their potential role was preserved in the plant lineage. CONCLUSION Our analysis presents general features of the gene and protein structure of this splicing factor family and will provide fundamental information for further functional studies in plants.
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Affiliation(s)
- Kai-Lu Zhang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037 Jiangsu Province China
| | - Zhen Feng
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu Province China
| | - Jing-Fang Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079 China
| | - Feng Yang
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Tian Yuan
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Di Zhang
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Ge-Fei Hao
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079 China
| | - Yan-Ming Fang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037 Jiangsu Province China
| | - Jianhua Zhang
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
- Department of Biology, Hong Kong Baptist University, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Caie Wu
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, 210037 Jiangsu Province China
| | - Mo-Xian Chen
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055 PR China
| | - Fu-Yuan Zhu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037 Jiangsu Province China
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40
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Spliceosomal factor mutations and mis-splicing in MDS. Best Pract Res Clin Haematol 2020; 33:101199. [PMID: 33038983 DOI: 10.1016/j.beha.2020.101199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 02/06/2023]
Abstract
Somatic, heterozygous missense and nonsense mutations in at least seven proteins that function in the spliceosome are found at high frequency in MDS patients. These proteins act at various steps in the process of splicing by the spliceosome and lead to characteristic alterations in the alternative splicing of a subset of genes. Several studies have investigated the effects of these mutations and have attempted to identify a commonly affected gene or pathway. Here, we summarize what is known about the normal function of these proteins and how the mutations alter the splicing landscape of the genome. We also summarize the commonly mis-spliced gene targets and discuss the state of mechanistic unification that has been achieved. Finally, we discuss alternative mechanisms by which these mutations may lead to disease.
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41
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Wan Q, Song D, Li H, He ML. Stress proteins: the biological functions in virus infection, present and challenges for target-based antiviral drug development. Signal Transduct Target Ther 2020; 5:125. [PMID: 32661235 PMCID: PMC7356129 DOI: 10.1038/s41392-020-00233-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/26/2020] [Accepted: 06/13/2020] [Indexed: 02/06/2023] Open
Abstract
Stress proteins (SPs) including heat-shock proteins (HSPs), RNA chaperones, and ER associated stress proteins are molecular chaperones essential for cellular homeostasis. The major functions of HSPs include chaperoning misfolded or unfolded polypeptides, protecting cells from toxic stress, and presenting immune and inflammatory cytokines. Regarded as a double-edged sword, HSPs also cooperate with numerous viruses and cancer cells to promote their survival. RNA chaperones are a group of heterogeneous nuclear ribonucleoproteins (hnRNPs), which are essential factors for manipulating both the functions and metabolisms of pre-mRNAs/hnRNAs transcribed by RNA polymerase II. hnRNPs involve in a large number of cellular processes, including chromatin remodelling, transcription regulation, RNP assembly and stabilization, RNA export, virus replication, histone-like nucleoid structuring, and even intracellular immunity. Dysregulation of stress proteins is associated with many human diseases including human cancer, cardiovascular diseases, neurodegenerative diseases (e.g., Parkinson’s diseases, Alzheimer disease), stroke and infectious diseases. In this review, we summarized the biologic function of stress proteins, and current progress on their mechanisms related to virus reproduction and diseases caused by virus infections. As SPs also attract a great interest as potential antiviral targets (e.g., COVID-19), we also discuss the present progress and challenges in this area of HSP-based drug development, as well as with compounds already under clinical evaluation.
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Affiliation(s)
- Qianya Wan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Dan Song
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Huangcan Li
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Ming-Liang He
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China. .,CityU Shenzhen Research Institute, Shenzhen, China.
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Tavanez JP, Caetano R, Branco C, Brito IM, Miragaia-Pereira A, Vassilevskaia T, Quina AS, Cunha C. Hepatitis delta virus interacts with splicing factor SF3B155 and alters pre-mRNA splicing of cell cycle control genes. FEBS J 2020; 287:3719-3732. [PMID: 32352217 DOI: 10.1111/febs.15352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/14/2019] [Accepted: 04/28/2020] [Indexed: 11/28/2022]
Abstract
Hepatitis delta virus (HDV) is the agent responsible for the most severe form of human viral hepatitis. The HDV genome consists of a single-stranded circular RNA molecule that encodes for one single protein, the delta antigen. Given its simplicity, HDV must make use of several host cellular proteins to accomplish its life cycle processes, including transcription, replication, post-transcriptional, and post-translational modifications. Consequently, identification of the interactions established between HDV components and host proteins assumes a pivotal interest in the search of novel therapeutic targets. Here, we used the yeast three-hybrid system to screen a human liver cDNA library to identify host proteins that interact with the HDV genomic RNA. One of the identified proteins corresponded to the splicing factor SF3B155, a component of the U2snRNP complex that is essential for the early recognition of 3' splice sites in the pre-mRNAs of human genes. We show that the interaction between the HDV genomic RNA and SF3B155 occurs in vivo and that the expression of HDV promotes changes in splicing of human genes whose alternative splicing is SF3B155-dependent. We further show that expression of HDV triggers alterations in several constitutive and alternative splicing events in the tumor suppressor RBM5 transcript, with consequent reduction of its protein levels. This is the first description that HDV expression promotes changes in the splicing of human genes, and we suggest that the HDV-induced alternative splicing changes, through SF3B155 sequester, may contribute for the early progression to hepatocellular carcinoma characteristic of HDV-infected patients.
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Affiliation(s)
- João Paulo Tavanez
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Rafael Caetano
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Cristina Branco
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Inês Margarida Brito
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Ana Miragaia-Pereira
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Tatiana Vassilevskaia
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Ana Sofia Quina
- CESAM - Centre for Environmental and Marine Studies, Universidade de Aveiro, Portugal.,Faculdade de Ciências da Universidade de Lisboa, Portugal
| | - Celso Cunha
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
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43
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Samy A, Suzek BE, Ozdemir MK, Sensoy O. In Silico Analysis of a Highly Mutated Gene in Cancer Provides Insight into Abnormal mRNA Splicing: Splicing Factor 3B Subunit 1 K700E Mutant. Biomolecules 2020; 10:E680. [PMID: 32354150 PMCID: PMC7277358 DOI: 10.3390/biom10050680] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 12/25/2022] Open
Abstract
Cancer is the second leading cause of death worldwide. The etiology of the disease has remained elusive, but mutations causing aberrant RNA splicing have been considered one of the significant factors in various cancer types. The association of aberrant RNA splicing with drug/therapy resistance further increases the importance of these mutations. In this work, the impact of the splicing factor 3B subunit 1 (SF3B1) K700E mutation, a highly prevalent mutation in various cancer types, is investigated through molecular dynamics simulations. Based on our results, K700E mutation increases flexibility of the mutant SF3B1. Consequently, this mutation leads to i) disruption of interaction of pre-mRNA with SF3B1 and p14, thus preventing proper alignment of mRNA and causing usage of abnormal 3' splice site, and ii) disruption of communication in critical regions participating in interactions with other proteins in pre-mRNA splicing machinery. We anticipate that this study enhances our understanding of the mechanism of functional abnormalities associated with splicing machinery, thereby, increasing possibility for designing effective therapies to combat cancer at an earlier stage.
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Affiliation(s)
- Asmaa Samy
- The Graduate School of Engineering and Natural Science, Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Baris Ethem Suzek
- Department of Computer Engineering, Muğla Sıtkı Koçman University, 48000 Muğla, Turkey
| | - Mehmet Kemal Ozdemir
- The School of Engineering and Natural Science, Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Ozge Sensoy
- The School of Engineering and Natural Science, Istanbul Medipol University, 34810 Istanbul, Turkey
- Regenerative and Restorative Medicine Research Center (REMER), Istanbul Medipol University, 34810 Istanbul, Turkey
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44
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Kaur H, Groubert B, Paulson JC, McMillan S, Hoskins AA. Impact of cancer-associated mutations in Hsh155/SF3b1 HEAT repeats 9-12 on pre-mRNA splicing in Saccharomyces cerevisiae. PLoS One 2020; 15:e0229315. [PMID: 32320410 PMCID: PMC7176370 DOI: 10.1371/journal.pone.0229315] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/20/2020] [Indexed: 11/22/2022] Open
Abstract
Mutations in the splicing machinery have been implicated in a number of human diseases. Most notably, the U2 small nuclear ribonucleoprotein (snRNP) component SF3b1 has been found to be frequently mutated in blood cancers such as myelodysplastic syndromes (MDS). SF3b1 is a highly conserved HEAT repeat (HR)-containing protein and most of these blood cancer mutations cluster in a hot spot located in HR4-8. Recently, a second mutational hotspot has been identified in SF3b1 located in HR9-12 and is associated with acute myeloid leukemias, bladder urothelial carcinomas, and uterine corpus endometrial carcinomas. The consequences of these mutations on SF3b1 functions during splicing have not yet been tested. We incorporated the corresponding mutations into the yeast homolog of SF3b1 and tested their impact on splicing. We find that all of these HR9-12 mutations can support splicing in yeast, and this suggests that none of them are loss of function alleles in humans. The Hsh155V502F mutation alters splicing of several pre-mRNA reporters containing weak branch sites as well as a genetic interaction with Prp2 and physical interactions with Prp5 and Prp3. The ability of a single allele of Hsh155 to perturb interactions with multiple factors functioning at different stages of the splicing reaction suggests that some SF3b1-mutant disease phenotypes may have a complex origin on the spliceosome.
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Affiliation(s)
- Harpreet Kaur
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Brent Groubert
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Joshua C. Paulson
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sarah McMillan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Aaron A. Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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45
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Tang AD, Soulette CM, van Baren MJ, Hart K, Hrabeta-Robinson E, Wu CJ, Brooks AN. Full-length transcript characterization of SF3B1 mutation in chronic lymphocytic leukemia reveals downregulation of retained introns. Nat Commun 2020; 11:1438. [PMID: 32188845 PMCID: PMC7080807 DOI: 10.1038/s41467-020-15171-6] [Citation(s) in RCA: 211] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 02/06/2020] [Indexed: 01/01/2023] Open
Abstract
While splicing changes caused by somatic mutations in SF3B1 are known, identifying full-length isoform changes may better elucidate the functional consequences of these mutations. We report nanopore sequencing of full-length cDNA from CLL samples with and without SF3B1 mutation, as well as normal B cell samples, giving a total of 149 million pass reads. We present FLAIR (Full-Length Alternative Isoform analysis of RNA), a computational workflow to identify high-confidence transcripts, perform differential splicing event analysis, and differential isoform analysis. Using nanopore reads, we demonstrate differential 3' splice site changes associated with SF3B1 mutation, agreeing with previous studies. We also observe a strong downregulation of intron retention events associated with SF3B1 mutation. Full-length transcript analysis links multiple alternative splicing events together and allows for better estimates of the abundance of productive versus unproductive isoforms. Our work demonstrates the potential utility of nanopore sequencing for cancer and splicing research.
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Affiliation(s)
- Alison D Tang
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA, 95062, USA
| | - Cameron M Soulette
- Department of Molecular Cell & Developmental Biology, University of California, Santa Cruz, CA, 95062, USA
| | - Marijke J van Baren
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA, 95062, USA
| | - Kevyn Hart
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA, 95062, USA
| | - Eva Hrabeta-Robinson
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA, 95062, USA
| | - Catherine J Wu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Broad Institiute of Harvard and MIT, Cambridge, MA, USA
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Angela N Brooks
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA, 95062, USA.
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Fujita KI, Ishizuka T, Mitsukawa M, Kurata M, Masuda S. Regulating Divergent Transcriptomes through mRNA Splicing and Its Modulation Using Various Small Compounds. Int J Mol Sci 2020; 21:ijms21062026. [PMID: 32188117 PMCID: PMC7139312 DOI: 10.3390/ijms21062026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 12/14/2022] Open
Abstract
Human transcriptomes are more divergent than genes and contribute to the sophistication of life. This divergence is derived from various isoforms arising from alternative splicing. In addition, alternative splicing regulated by spliceosomal factors and RNA structures, such as the RNA G-quadruplex, is important not only for isoform diversity but also for regulating gene expression. Therefore, abnormal splicing leads to serious diseases such as cancer and neurodegenerative disorders. In the first part of this review, we describe the regulation of divergent transcriptomes using alternative mRNA splicing. In the second part, we present the relationship between the disruption of splicing and diseases. Recently, various compounds with splicing inhibitor activity were established. These splicing inhibitors are recognized as a biological tool to investigate the molecular mechanism of splicing and as a potential therapeutic agent for cancer treatment. Food-derived compounds with similar functions were found and are expected to exhibit anticancer effects. In the final part, we describe the compounds that modulate the messenger RNA (mRNA) splicing process and their availability for basic research and future clinical potential.
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47
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van der Feltz C, Hoskins AA. Structural and functional modularity of the U2 snRNP in pre-mRNA splicing. Crit Rev Biochem Mol Biol 2019; 54:443-465. [PMID: 31744343 DOI: 10.1080/10409238.2019.1691497] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The U2 small nuclear ribonucleoprotein (snRNP) is an essential component of the spliceosome, the cellular machine responsible for removing introns from precursor mRNAs (pre-mRNAs) in all eukaryotes. U2 is an extraordinarily dynamic splicing factor and the most frequently mutated in cancers. Cryo-electron microscopy (cryo-EM) has transformed our structural and functional understanding of the role of U2 in splicing. In this review, we synthesize these and other data with respect to a view of U2 as an assembly of interconnected functional modules. These modules are organized by the U2 small nuclear RNA (snRNA) for roles in spliceosome assembly, intron substrate recognition, and protein scaffolding. We describe new discoveries regarding the structure of U2 components and how the snRNP undergoes numerous conformational and compositional changes during splicing. We specifically highlight large scale movements of U2 modules as the spliceosome creates and rearranges its active site. U2 serves as a compelling example for how cellular machines can exploit the modular organization and structural plasticity of an RNP.
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Affiliation(s)
| | - Aaron A Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
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48
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Maita H, Nakagawa S. What is the switch for coupling transcription and splicing? RNA Polymerase II C‐terminal domain phosphorylation, phase separation and beyond. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1574. [DOI: 10.1002/wrna.1574] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 01/12/2023]
Affiliation(s)
- Hiroshi Maita
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences Hokkaido University Sapporo Japan
| | - Shinichi Nakagawa
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences Hokkaido University Sapporo Japan
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49
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Martelly W, Fellows B, Senior K, Marlowe T, Sharma S. Identification of a noncanonical RNA binding domain in the U2 snRNP protein SF3A1. RNA (NEW YORK, N.Y.) 2019; 25:1509-1521. [PMID: 31383795 PMCID: PMC6795144 DOI: 10.1261/rna.072256.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
During splicing of pre-mRNA, 5' and 3' splice sites are brought within proximity by interactions between the pre-mRNA bound U1 and U2 snRNPs, followed by recruitment of the tri-snRNP for assembly of the mature spliceosome. Previously, we identified an interaction between the U2 snRNP-specific protein SF3A1 and the stem-loop 4 (SL4) of the U1 snRNA that occurs during the early steps of spliceosome assembly. Although harboring many annotated domains, SF3A1 lacks a canonical RNA binding domain. To identify the U1-SL4 binding region in SF3A1, we expressed amino- and carboxy-terminal deletion constructs using a HeLa cell-based cell free expression system. UV-crosslinking of the truncated proteins with 32P-U1-SL4 RNA identified the carboxy-terminal ubiquitin-like (UBL) domain of SF3A1 as the RNA binding region. Characterization of the interaction between SF3A1-UBL and U1-SL4 by electrophoretic mobility shift assay and surface plasmon resonance determined high binding affinity (KD = ∼97 nM), and revealed the double-stranded G-C rich stem of U1-SL4 as an important feature for binding to the UBL domain. Further, mutations of two conserved tyrosine residues, Y772 and Y773, were found to cause a two- and fivefold decrease in the binding affinity for U1-SL4, respectively. Finally, we found that SF3A1-UBL can specifically pull down the U1 snRNP from HeLa nuclear extract, demonstrating its capacity to bind U1-SL4 in the context of the intact snRNP. Thus, the data show that the UBL domain of SF3A1 can function as an RNA binding domain and that mutations in this region may interfere with U1-SL4 binding.
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Affiliation(s)
- William Martelly
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA
| | - Bernice Fellows
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
| | - Kristen Senior
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
| | - Tim Marlowe
- Molecular Analysis Core, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
| | - Shalini Sharma
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA
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50
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Kastner B, Will CL, Stark H, Lührmann R. Structural Insights into Nuclear pre-mRNA Splicing in Higher Eukaryotes. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032417. [PMID: 30765414 DOI: 10.1101/cshperspect.a032417] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The spliceosome is a highly complex, dynamic ribonucleoprotein molecular machine that undergoes numerous structural and compositional rearrangements that lead to the formation of its active site. Recent advances in cyroelectron microscopy (cryo-EM) have provided a plethora of near-atomic structural information about the inner workings of the spliceosome. Aided by previous biochemical, structural, and functional studies, cryo-EM has confirmed or provided a structural basis for most of the prevailing models of spliceosome function, but at the same time allowed novel insights into splicing catalysis and the intriguing dynamics of the spliceosome. The mechanism of pre-mRNA splicing is highly conserved between humans and yeast, but the compositional dynamics and ribonucleoprotein (RNP) remodeling of the human spliceosome are more complex. Here, we summarize recent advances in our understanding of the molecular architecture of the human spliceosome, highlighting differences between the human and yeast splicing machineries.
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Affiliation(s)
- Berthold Kastner
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Cindy L Will
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Holger Stark
- Department of Structural Dynamics, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
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