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Burnight ER, Fenner BJ, Han IC, DeLuca AP, Whitmore SS, Bohrer LR, Andorf JL, Sohn EH, Mullins RF, Tucker BA, Stone EM. Demonstration of the pathogenicity of a common non-exomic mutation in ABCA4 using iPSC-derived retinal organoids and retrospective clinical data. Hum Mol Genet 2024; 33:1379-1390. [PMID: 37930186 PMCID: PMC11305681 DOI: 10.1093/hmg/ddad176] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 09/25/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023] Open
Abstract
Mutations in ABCA4 are the most common cause of Mendelian retinal disease. Clinical evaluation of this gene is challenging because of its extreme allelic diversity, the large fraction of non-exomic mutations, and the wide range of associated disease. We used patient-derived retinal organoids as well as DNA samples and clinical data from a large cohort of patients with ABCA4-associated retinal disease to investigate the pathogenicity of a variant in ABCA4 (IVS30 + 1321 A>G) that occurs heterozygously in 2% of Europeans. We found that this variant causes mis-splicing of the gene in photoreceptor cells such that the resulting protein contains 36 incorrect amino acids followed by a premature stop. We also investigated the phenotype of 10 patients with compound genotypes that included this mutation. Their median age of first vision loss was 39 years, which is in the mildest quintile of a large cohort of patients with ABCA4 disease. We conclude that the IVS30 + 1321 A>G variant can cause disease when paired with a sufficiently deleterious opposing allele in a sufficiently permissive genetic background.
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Affiliation(s)
- Erin R Burnight
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Beau J Fenner
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Ian C Han
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Adam P DeLuca
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - S Scott Whitmore
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Laura R Bohrer
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Jeaneen L Andorf
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Elliott H Sohn
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Robert F Mullins
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Budd A Tucker
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
| | - Edwin M Stone
- Institute for Vision Research, Carver College of Medicine, University of Iowa, 375 Newton Road, Iowa City, IA 52242, United States
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, United States
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Casados-Delgado O, Avalos-Fuentes JA, Lara-Lozano M, Tovar-Medina G, Florán-Hernández CD, Martínez-Nolasco KG, Cortes H, Felix R, Segovia J, Florán B. Modulation of D 3R Splicing, Signaling, and Expression by D 1R through PKA→PTB Phosphorylation. Biomedicines 2024; 12:206. [PMID: 38255311 PMCID: PMC10813448 DOI: 10.3390/biomedicines12010206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
The D1R and D3R receptors functionally and synergistically interact in striatonigral neurons. Dopaminergic denervation turns this interaction antagonistic, which is correlated with a decrement in D3nf isoform and an increment in D3R membranal expression. The mechanisms of such changes in D3R are attributed to the dysregulation of the expression of their isoforms. The cause and mechanism of this phenomenon remain unknown. Dopaminergic denervation produces a decrement in D1R and PKA activity; we propose that the lack of phosphorylation of PTB (regulator of alternative splicing) by PKA produces the dysregulation of D3R splicing and changes D3R functionality. By using in silico analysis, we found that D3R mRNA has motifs for PTB binding and, by RIP, co-precipitates with PTB. Moreover, D1R activation via PKA promotes PTB phosphorylation. Acute and 5-day D1R blockade decreases the expression of D3nf mRNA. The 5-day treatment reduces D3R, D3nf, and PTB protein in the cytoplasm and increases D3R in the membrane and PTB in the nucleus. Finally, the blockade of D1R mimics the effect of dopaminergic denervation in D1R and D3R signaling. Thus, our data indicate that through PKA→PTB, D1R modulates D3R splicing, expression, and signaling, which are altered during D1R blockade or the lack of stimulation in dopaminergic denervation.
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Affiliation(s)
- Orlando Casados-Delgado
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
| | - José Arturo Avalos-Fuentes
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
| | - Manuel Lara-Lozano
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
| | - Gisela Tovar-Medina
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
| | - Carla Daniela Florán-Hernández
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
| | - Karla Gisela Martínez-Nolasco
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
| | - Hernán Cortes
- Laboratorio de Medicina Genómica, Departamento de Genómica, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico;
| | - Ricardo Felix
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico;
| | - José Segovia
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
| | - Benjamín Florán
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City 07360, Mexico; (O.C.-D.); (J.A.A.-F.); (M.L.-L.); (G.T.-M.); (C.D.F.-H.); (K.G.M.-N.); (J.S.)
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3
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Arfelli VC, Chang YC, Bagnoli JW, Kerbs P, Ciamponi FE, Paz LMDS, Pankivskyi S, de Matha Salone J, Maucuer A, Massirer KB, Enard W, Kuster B, Greif PA, Archangelo LF. UHMK1 is a novel splicing regulatory kinase. J Biol Chem 2023; 299:103041. [PMID: 36803961 PMCID: PMC10033318 DOI: 10.1016/j.jbc.2023.103041] [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: 06/01/2022] [Revised: 01/18/2023] [Accepted: 02/04/2023] [Indexed: 02/19/2023] Open
Abstract
The U2AF Homology Motif Kinase 1 (UHMK1) is the only kinase that contains the U2AF homology motif, a common protein interaction domain among splicing factors. Through this motif, UHMK1 interacts with the splicing factors SF1 and SF3B1, known to participate in the 3' splice site recognition during the early steps of spliceosome assembly. Although UHMK1 phosphorylates these splicing factors in vitro, the involvement of UHMK1 in RNA processing has not previously been demonstrated. Here, we identify novel putative substrates of this kinase and evaluate UHMK1 contribution to overall gene expression and splicing, by integrating global phosphoproteomics, RNA-seq, and bioinformatics approaches. Upon UHMK1 modulation, 163 unique phosphosites were differentially phosphorylated in 117 proteins, of which 106 are novel potential substrates of this kinase. Gene Ontology analysis showed enrichment of terms previously associated with UHMK1 function, such as mRNA splicing, cell cycle, cell division, and microtubule organization. The majority of the annotated RNA-related proteins are components of the spliceosome but are also involved in several steps of gene expression. Comprehensive analysis of splicing showed that UHMK1 affected over 270 alternative splicing events. Moreover, splicing reporter assay further supported UHMK1 function on splicing. Overall, RNA-seq data demonstrated that UHMK1 knockdown had a minor impact on transcript expression and pointed to UHMK1 function in epithelial-mesenchymal transition. Functional assays demonstrated that UHMK1 modulation affects proliferation, colony formation, and migration. Taken together, our data implicate UHMK1 as a splicing regulatory kinase, connecting protein regulation through phosphorylation and gene expression in key cellular processes.
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Affiliation(s)
- Vanessa C Arfelli
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
| | - Yun-Chien Chang
- Proteomics and Bioanalytics, School of Life Sciences Weihenstephan, Technical University of Munich (TUM), Freising, Germany
| | - Johannes W Bagnoli
- Anthropology & Human Genomics, Department of Biology II, Ludwig-Maximilians-University (LMU), Martinsried, Germany
| | - Paul Kerbs
- Laboratory for Experimental Leukemia and Lymphoma Research, Munich University Hospital, Ludwig-Maximilians University (LMU), Munich, Germany; German Cancer Consortium (DKTK), partner site Munich, Munich, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Felipe E Ciamponi
- Center for Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Laissa M da S Paz
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
| | - Serhii Pankivskyi
- SABNP, Univ Evry, INSERM U1204, Université Paris-Saclay, Evry, France
| | | | - Alexandre Maucuer
- SABNP, Univ Evry, INSERM U1204, Université Paris-Saclay, Evry, France
| | - Katlin B Massirer
- Center for Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Wolfgang Enard
- Anthropology & Human Genomics, Department of Biology II, Ludwig-Maximilians-University (LMU), Martinsried, Germany
| | - Bernhard Kuster
- Proteomics and Bioanalytics, School of Life Sciences Weihenstephan, Technical University of Munich (TUM), Freising, Germany
| | - Philipp A Greif
- Laboratory for Experimental Leukemia and Lymphoma Research, Munich University Hospital, Ludwig-Maximilians University (LMU), Munich, Germany; German Cancer Consortium (DKTK), partner site Munich, Munich, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Leticia Fröhlich Archangelo
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil.
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4
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Bioinformatic Analysis of Genetic Factors from Human Blood Samples and Postmortem Brains in Parkinson's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:9235358. [PMID: 36593912 PMCID: PMC9805394 DOI: 10.1155/2022/9235358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/25/2022]
Abstract
Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders characterized by motor and nonmotor symptoms due to the selective loss of midbrain dopaminergic neurons. Pharmacological and surgical interventions have not been possible to cure PD; however, the cause of neurodegeneration remains unclear. Here, we performed and tested a multitiered bioinformatic analysis using the GEO and Proteinexchange database to investigate the gene expression involved in the pathogenesis of PD. Then we further validated individual differences in gene expression in whole blood samples that we collected in the clinic. We also made an interaction analysis and prediction for these genetic factors. There were in all 1045 genes expressing differently in PD compared with the healthy control group. Protein-protein interaction (PPI) networks showed 10 top hub genes: ACO2, MDH2, SDHA, ATP5A1, UQCRC2, PDHB, SUCLG1, NDUFS3, UQCRC1, and ATP5C1. We validated the ten hub gene expression in clinical PD patients and showed the expression of MDH2 was significantly different compared with healthy control. Besides, we also identified the expression of G6PD, GRID2, RIPK2, CUL4B, BCL6, MRPS31, GPI, and MAP 2 K1 were all significantly increased, and levels of MAPK, ELAVL1, RAB14, KLF9, ARF1, ARFGAP1, ATG7, ABCA7, SFT2D2, E2F2, MAPK7, and UHRF1 were all significantly decreased in PD. Among them, to our knowledge, we presently have the most recent and conclusive evidence that GRID2, RIPK2, CUL4B, E2F2, and ABCA7 are possible PD indicators. We confirmed several genetic factors which may be involved in the pathogenesis of PD. They could be promising markers for discriminating the PD and potential factors that may affect PD development.
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5
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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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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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7
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Horiuchi K, Kawamura T, Hamakubo T. Wilms' Tumor 1-Associating Protein complex regulates alternative splicing and polyadenylation at potential G-quadruplex-forming splice site sequences. J Biol Chem 2021; 297:101248. [PMID: 34582888 PMCID: PMC8605363 DOI: 10.1016/j.jbc.2021.101248] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 09/17/2021] [Accepted: 09/23/2021] [Indexed: 11/14/2022] Open
Abstract
Wilms’ tumor 1-associating protein (WTAP) is a core component of the N6-methyladenosine (m6A)-methyltransferase complex, along with VIRMA, CBLL1, ZC3H13 (KIAA0853), RBM15/15B, and METTL3/14, which generate m6A, a key RNA modification that affects various processes of RNA metabolism. WTAP also interacts with splicing factors; however, despite strong evidence suggesting a role of Drosophila WTAP homolog fl(2)d in alternative splicing (AS), its role in splicing regulation in mammalian cells remains elusive. Here we demonstrate using RNAi coupled with RNA-seq that WTAP, VIRMA, CBLL1, and ZC3H13 modulate AS, promoting exon skipping and intron retention in AS events that involve short introns/exons with higher GC content and introns with weaker polypyrimidine-tract and branch points. Further analysis of GC-rich sequences involved in AS events regulated by WTAP, together with minigene assay analysis, revealed potential G-quadruplex formation at splice sites where WTAP has an inhibitory effect. We also found that several AS events occur in the last exon of one isoform of MSL1 and WTAP, leading to competition for polyadenylation. Proteomic analysis also suggested that WTAP/CBLL1 interaction promotes recruitment of the 3′-end processing complex. Taken together, our results indicate that the WTAP complex regulates AS and alternative polyadenylation via inhibitory mechanisms in GC-rich sequences.
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Affiliation(s)
- Keiko Horiuchi
- Department of Protein-Protein Interaction Research, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-0011, Japan.
| | - Takeshi Kawamura
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Takao Hamakubo
- Department of Protein-Protein Interaction Research, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-0011, Japan.
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Kao SY, Nikonova E, Chaabane S, Sabani A, Martitz A, Wittner A, Heemken J, Straub T, Spletter ML. A Candidate RNAi Screen Reveals Diverse RNA-Binding Protein Phenotypes in Drosophila Flight Muscle. Cells 2021; 10:2505. [PMID: 34685485 PMCID: PMC8534295 DOI: 10.3390/cells10102505] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/14/2021] [Accepted: 09/18/2021] [Indexed: 12/30/2022] Open
Abstract
The proper regulation of RNA processing is critical for muscle development and the fine-tuning of contractile ability among muscle fiber-types. RNA binding proteins (RBPs) regulate the diverse steps in RNA processing, including alternative splicing, which generates fiber-type specific isoforms of structural proteins that confer contractile sarcomeres with distinct biomechanical properties. Alternative splicing is disrupted in muscle diseases such as myotonic dystrophy and dilated cardiomyopathy and is altered after intense exercise as well as with aging. It is therefore important to understand splicing and RBP function, but currently, only a small fraction of the hundreds of annotated RBPs expressed in muscle have been characterized. Here, we demonstrate the utility of Drosophila as a genetic model system to investigate basic developmental mechanisms of RBP function in myogenesis. We find that RBPs exhibit dynamic temporal and fiber-type specific expression patterns in mRNA-Seq data and display muscle-specific phenotypes. We performed knockdown with 105 RNAi hairpins targeting 35 RBPs and report associated lethality, flight, myofiber and sarcomere defects, including flight muscle phenotypes for Doa, Rm62, mub, mbl, sbr, and clu. Knockdown phenotypes of spliceosome components, as highlighted by phenotypes for A-complex components SF1 and Hrb87F (hnRNPA1), revealed level- and temporal-dependent myofibril defects. We further show that splicing mediated by SF1 and Hrb87F is necessary for Z-disc stability and proper myofibril development, and strong knockdown of either gene results in impaired localization of kettin to the Z-disc. Our results expand the number of RBPs with a described phenotype in muscle and underscore the diversity in myofibril and transcriptomic phenotypes associated with splicing defects. Drosophila is thus a powerful model to gain disease-relevant insight into cellular and molecular phenotypes observed when expression levels of splicing factors, spliceosome components and splicing dynamics are altered.
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Affiliation(s)
- Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Sabrina Chaabane
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Albiona Sabani
- Department of Biology, University of Wisconsin at Madison, 1117 W. Johnson St., Madison, WI 53706, USA;
| | - Alexandra Martitz
- Molecular Nutrition Medicine, Else Kröner-Fresenius Center, Technical University of Munich, 85354 Freising, Germany;
| | - Anja Wittner
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Jakob Heemken
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Tobias Straub
- Biomedical Center, Bioinformatics Core Facility, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany;
| | - Maria L. Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
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9
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Beneventi G, Munita R, Cao Thi Ngoc P, Madej M, Cieśla M, Muthukumar S, Krogh N, Nielsen H, Swaminathan V, Bellodi C. The small Cajal body-specific RNA 15 (SCARNA15) directs p53 and redox homeostasis via selective splicing in cancer cells. NAR Cancer 2021; 3:zcab026. [PMID: 34316713 PMCID: PMC8271217 DOI: 10.1093/narcan/zcab026] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/19/2021] [Accepted: 06/18/2021] [Indexed: 01/05/2023] Open
Abstract
Small Cajal body-specific RNAs (scaRNAs) guide post-transcriptional modification of spliceosomal RNA and, while commonly altered in cancer, have poorly defined roles in tumorigenesis. Here, we uncover that SCARNA15 directs alternative splicing (AS) and stress adaptation in cancer cells. Specifically, we find that SCARNA15 guides critical pseudouridylation (Ψ) of U2 spliceosomal RNA to fine-tune AS of distinct transcripts enriched for chromatin and transcriptional regulators in malignant cells. This critically impacts the expression and function of the key tumor suppressors ATRX and p53. Significantly, SCARNA15 loss impairs p53-mediated redox homeostasis and hampers cancer cell survival, motility and anchorage-independent growth. In sum, these findings highlight an unanticipated role for SCARNA15 and Ψ in directing cancer-associated splicing programs.
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Affiliation(s)
- Giulia Beneventi
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184, Lund, Sweden
| | - Roberto Munita
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184, Lund, Sweden
| | - Phuong Cao Thi Ngoc
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184, Lund, Sweden
| | - Magdalena Madej
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Faculty of Medicine, Lund University, 22184, Lund, Sweden
| | - Maciej Cieśla
- 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
| | - Nicolai Krogh
- Department of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Vinay Swaminathan
- Division of Oncology, Department of Clinical Sciences, Lund University, 22184, Lund, 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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Wang Y, Yu Y, Pang Y, Yu H, Zhang W, Zhao X, Yu J. The distinct roles of zinc finger CCHC-type (ZCCHC) superfamily proteins in the regulation of RNA metabolism. RNA Biol 2021; 18:2107-2126. [PMID: 33787465 DOI: 10.1080/15476286.2021.1909320] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The zinc finger CCHC-type (ZCCHC) superfamily proteins, characterized with the consensus sequence C-X2-C-X4-H-X4-C, are accepted to have high-affinity binding to single-stranded nucleic acids, especially single-stranded RNAs. In human beings 25 ZCCHC proteins have been annotated in the HGNC database. Of interest is that among the family, most members are involved in the multiple steps of RNA metabolism. In this review, we focus on the diverged roles of human ZCCHC proteins on RNA transcription, biogenesis, splicing, as well as translation and degradation.
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Affiliation(s)
- Yishu Wang
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China
| | - Yu Yu
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yidan Pang
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haojun Yu
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenqi Zhang
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xian Zhao
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianxiu Yu
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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11
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Královičová J, Borovská I, Pengelly R, Lee E, Abaffy P, Šindelka R, Grutzner F, Vořechovský I. Restriction of an intron size en route to endothermy. Nucleic Acids Res 2021; 49:2460-2487. [PMID: 33550394 PMCID: PMC7969005 DOI: 10.1093/nar/gkab046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 11/15/2022] Open
Abstract
Ca2+-insensitive and -sensitive E1 subunits of the 2-oxoglutarate dehydrogenase complex (OGDHC) regulate tissue-specific NADH and ATP supply by mutually exclusive OGDH exons 4a and 4b. Here we show that their splicing is enforced by distant lariat branch points (dBPs) located near the 5' splice site of the intervening intron. dBPs restrict the intron length and prevent transposon insertions, which can introduce or eliminate dBP competitors. The size restriction was imposed by a single dominant dBP in anamniotes that expanded into a conserved constellation of four dBP adenines in amniotes. The amniote clusters exhibit taxon-specific usage of individual dBPs, reflecting accessibility of their extended motifs within a stable RNA hairpin rather than U2 snRNA:dBP base-pairing. The dBP expansion took place in early terrestrial species and was followed by a uridine enrichment of large downstream polypyrimidine tracts in mammals. The dBP-protected megatracts permit reciprocal regulation of exon 4a and 4b by uridine-binding proteins, including TIA-1/TIAR and PUF60, which promote U1 and U2 snRNP recruitment to the 5' splice site and BP, respectively, but do not significantly alter the relative dBP usage. We further show that codons for residues critically contributing to protein binding sites for Ca2+ and other divalent metals confer the exon inclusion order that mirrors the Irving-Williams affinity series, linking the evolution of auxiliary splicing motifs in exons to metallome constraints. Finally, we hypothesize that the dBP-driven selection for Ca2+-dependent ATP provision by E1 facilitated evolution of endothermy by optimizing the aerobic scope in target tissues.
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Affiliation(s)
- Jana Královičová
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Ivana Borovská
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Reuben Pengelly
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
| | - Eunice Lee
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Pavel Abaffy
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Radek Šindelka
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Frank Grutzner
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Igor Vořechovský
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
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12
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Du JX, Zhu GQ, Cai JL, Wang B, Luo YH, Chen C, Cai CZ, Zhang SJ, Zhou J, Fan J, Zhu W, Dai Z. Splicing factors: Insights into their regulatory network in alternative splicing in cancer. Cancer Lett 2020; 501:83-104. [PMID: 33309781 DOI: 10.1016/j.canlet.2020.11.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 12/18/2022]
Abstract
More than 95% of all human genes are alternatively spliced after transcription, which enriches the diversity of proteins and regulates transcript and/or protein levels. The splicing isoforms produced from the same gene can manifest distinctly, even exerting opposite effects. Mounting evidence indicates that the alternative splicing (AS) mechanism is ubiquitous in various cancers and drives the generation and maintenance of various hallmarks of cancer, such as enhanced proliferation, inhibited apoptosis, invasion and metastasis, and angiogenesis. Splicing factors (SFs) play pivotal roles in the recognition of splice sites and the assembly of spliceosomes during AS. In this review, we mainly discuss the similarities and differences of SF domains, the details of SF function in AS, the effect of SF-driven pathological AS on different hallmarks of cancer, and the main drivers of SF expression level and subcellular localization. In addition, we briefly introduce the application prospects of targeted therapeutic strategies, including small-molecule inhibitors, siRNAs and splice-switching oligonucleotides (SSOs), from three perspectives (drivers, SFs and pathological AS). Finally, we share our insights into the potential direction of research on SF-centric AS-related regulatory networks.
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Affiliation(s)
- Jun-Xian Du
- Department of General Surgery, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China
| | - Gui-Qi Zhu
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China; Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Jia-Liang Cai
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China; Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Biao Wang
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China; Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Yi-Hong Luo
- Department of General Surgery, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China
| | - Cong Chen
- Department of General Surgery, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China
| | - Cheng-Zhe Cai
- Department of General Surgery, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China
| | - Si-Jia Zhang
- Department of General Surgery, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China
| | - Jian Zhou
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China; Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Jia Fan
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China; Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Wei Zhu
- Department of General Surgery, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China.
| | - Zhi Dai
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China; Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China.
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13
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Godavarthi JD, Polk S, Nunez L, Shivachar A, Glenn Griesinger NL, Matin A. Deficiency of Splicing Factor 1 (SF1) Reduces Intestinal Polyp Incidence in ApcMin/+ Mice. BIOLOGY 2020; 9:biology9110398. [PMID: 33202710 PMCID: PMC7697247 DOI: 10.3390/biology9110398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 11/08/2020] [Accepted: 11/10/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND Splicing factor 1 (SF1) is a conserved alternative splicing factor expressed in many different mammalian cell types. The genetically modified Sf1+/- (or Sf1β-geo/+) mice express reduced levels of SF1 protein in mouse tissues, including in cells of the intestines. Mutational inactivation of human adenomatous polyposis coli (APC) gene deregulates the Wnt signaling pathway and is a frequent genetic event in colon cancers. Mice with a point mutation in the Apc gene (ApcMin/+) also develop numerous intestinal polyps at a young age. Our aim was to determine the effect of reduced SF1 levels on polyp development due to the strong driver ApcMin/+ mutation. METHODS We utilized mice genetically deficient for expression of SF1 to assess how SF1 levels affect intestinal tumorigenesis. We crossed ApcMin/+ to Sf1+/- mice to generate a cohort of heterozygous mutant ApcMin/+;Sf1+/- mice and compared intestinal polyp development in these mice to that in a control cohort of sibling ApcMin/+ mice. We compared total polyp numbers, sizes of polyps and gender differences in polyp numbers between ApcMin/+;Sf1+/- and ApcMin/+ mice. RESULTS Our results showed that ApcMin/+ mice with lower SF1 expression developed 25-30% fewer intestinal polyps compared to their ApcMin/+ siblings with normal SF1 levels. Interestingly, this difference was most significant for females (ApcMin/+;Sf1+/- and ApcMin/+ females developed 39 and 55 median number of polyps, respectively). Furthermore, the difference in polyp numbers between ApcMin/+;Sf1+/- and ApcMin/+ mice was significant for smaller polyps with a size of 2 mm or less, whereas both groups developed similar numbers of larger polyps. CONCLUSIONS Our results suggest that lower SF1 levels likely inhibit the rate of initiation of polyp development due to ApcMin/+ driver mutation in the mouse intestine. Thus, therapeutic lowering of SF1 levels in the intestine could attenuate intestinal polyp development.
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Affiliation(s)
- Jyotsna D. Godavarthi
- Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX 77004, USA; (J.D.G.); (S.P.); (L.N.); (A.S.)
| | - Shahrazad Polk
- Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX 77004, USA; (J.D.G.); (S.P.); (L.N.); (A.S.)
| | - Lisa Nunez
- Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX 77004, USA; (J.D.G.); (S.P.); (L.N.); (A.S.)
| | - Amruthesh Shivachar
- Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX 77004, USA; (J.D.G.); (S.P.); (L.N.); (A.S.)
| | | | - Angabin Matin
- Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX 77004, USA; (J.D.G.); (S.P.); (L.N.); (A.S.)
- Correspondence: ; Tel.: +1-713-313-7160; Fax: +1-713-313-1091
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14
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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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15
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Zhang Z, He X, Liu Q, Tang J, Di R, Chu M. TGIF1 and SF1 polymorphisms are associated with litter size in Small Tail Han sheep. Reprod Domest Anim 2020; 55:1145-1153. [PMID: 32594576 PMCID: PMC7540012 DOI: 10.1111/rda.13753] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
TGF‐β induced factor homeobox 1 (TGIF1) and splicing factor 1 (SF1) are important for mammalian reproduction; however, the effects of these genes on litter size in sheep remain unexplored. In this study, we genotyped 768 ewes from seven sheep breeds at two loci: g.37871539C>T, a synonymous mutation of TGIF1; and g.42314637T>C, a 3′UTR variant of SF1. Our analysis of polymorphism revealed only two genotypes at locus g.37871539C>T in TGIF1, with most sheep populations being moderately polymorphic (0.25 < PIC < 0.5) at this site. In contrast, most breeds exhibited low polymorphism (PIC ≤0.25) at the SF1 locus g.42314637T>C. The association analysis revealed that a synonymous mutation at g.37871539C>T in TGIF1 was highly associated with litter size in Small Tail Han sheep, in which it causes a significant decrease in litter size. Conversely, while the SF1 3′UTR variant g.42314637T>C was also highly associated with litter size in sheep, it causes a significant increase in the number of litter size. Combined, these data provide valuable information regarding candidate genetic markers for sheep breeding programs.
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Affiliation(s)
- Zhuangbiao Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoyun He
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qiuyue Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jishun Tang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.,Institute of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, China
| | - Ran Di
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mingxing Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
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16
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Carbonell C, Ulsamer A, Vivori C, Papasaikas P, Böttcher R, Joaquin M, Miñana B, Tejedor JR, de Nadal E, Valcárcel J, Posas F. Functional Network Analysis Reveals the Relevance of SKIIP in the Regulation of Alternative Splicing by p38 SAPK. Cell Rep 2019; 27:847-859.e6. [PMID: 30995481 PMCID: PMC6484779 DOI: 10.1016/j.celrep.2019.03.060] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 02/21/2019] [Accepted: 03/15/2019] [Indexed: 01/03/2023] Open
Abstract
Alternative splicing is a prevalent mechanism of gene regulation that is modulated in response to a wide range of extracellular stimuli. Stress-activated protein kinases (SAPKs) play a key role in controlling several steps of mRNA biogenesis. Here, we show that osmostress has an impact on the regulation of alternative splicing (AS), which is partly mediated through the action of p38 SAPK. Splicing network analysis revealed a functional connection between p38 and the spliceosome component SKIIP, whose depletion abolished a significant fraction of p38-mediated AS changes. Importantly, p38 interacted with and directly phosphorylated SKIIP, thereby altering its activity. SKIIP phosphorylation regulated AS of GADD45α, the upstream activator of the p38 pathway, uncovering a negative feedback loop involving AS regulation. Our data reveal mechanisms and targets of SAPK function in stress adaptation through the regulation of AS.
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Affiliation(s)
- Caterina Carbonell
- Cell Signaling Research Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Arnau Ulsamer
- Cell Signaling Research Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Claudia Vivori
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Panagiotis Papasaikas
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - René Böttcher
- Cell Signaling Research Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain; Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Manel Joaquin
- Cell Signaling Research Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain; Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Belén Miñana
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Juan Ramón Tejedor
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Eulàlia de Nadal
- Cell Signaling Research Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain; Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain.
| | - Juan Valcárcel
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain.
| | - Francesc Posas
- Cell Signaling Research Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain; Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain.
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17
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Zhang R, Lin P, Yang X, He RQ, Wu HY, Dang YW, Gu YY, Peng ZG, Feng ZB, Chen G. Survival associated alternative splicing events in diffuse large B-cell lymphoma. Am J Transl Res 2018; 10:2636-2647. [PMID: 30210700 PMCID: PMC6129525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 07/25/2018] [Indexed: 06/08/2023]
Abstract
Growing evidence has revealed that the initiation of various malignancies is closely associated with alternative splicing (AS) events in certain key oncogenes. However, in diffuse large B-cell lymphoma (DLBCL), there is still a great deal to learn about AS variants. In this study, 33,724 AS variant profiles were obtained from 16,278 genes in 48 DLBCL cases. A total of 10 AS variants were identified as overall survival (OS)- related events via multivariate Cox regression analysis. Notably, alternative donor (AD) sites in AS events in the low-risk group showed a significantly better outcome in DLBCL patients than in the high-risk group (P=0.0002). The area under the curve (AUC) of the receiver-operator characteristic curve (ROC) for ADs in DLBCL was 0.746. Furthermore, 66 related splicing factors were obtained to investigate their potential correlations with AS events. Factors SF1, HNRNPC, HNRNPD, and HNRNPH3 were significantly involved in different OS-related AS variants. Collectively, we constructed valuable prognostic predictors for DLBCL patients and mapped novel splicing networks for further investigation of the underlying mechanisms related to AS variants in DLBCLs.
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Affiliation(s)
- Rui Zhang
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Peng Lin
- Department of Ultrasonography, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Xia Yang
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Rong-Quan He
- Department of Medical Oncology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Hua-Yu Wu
- Department of Cell Biology and Genetics, Guangxi Medical University22 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Yi-Wu Dang
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Yong-Yao Gu
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Zhi-Gang Peng
- Department of Medical Oncology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Zhen-Bo Feng
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Gang Chen
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University6 Shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, China
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18
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Fernandez JP, Moreno-Mateos MA, Gohr A, Miao L, Chan SH, Irimia M, Giraldez AJ. RES complex is associated with intron definition and required for zebrafish early embryogenesis. PLoS Genet 2018; 14:e1007473. [PMID: 29969449 PMCID: PMC6047831 DOI: 10.1371/journal.pgen.1007473] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 07/16/2018] [Accepted: 06/06/2018] [Indexed: 12/16/2022] Open
Abstract
Pre-mRNA splicing is a critical step of gene expression in eukaryotes. Transcriptome-wide splicing patterns are complex and primarily regulated by a diverse set of recognition elements and associated RNA-binding proteins. The retention and splicing (RES) complex is formed by three different proteins (Bud13p, Pml1p and Snu17p) and is involved in splicing in yeast. However, the importance of the RES complex for vertebrate splicing, the intronic features associated with its activity, and its role in development are unknown. In this study, we have generated loss-of-function mutants for the three components of the RES complex in zebrafish and showed that they are required during early development. The mutants showed a marked neural phenotype with increased cell death in the brain and a decrease in differentiated neurons. Transcriptomic analysis of bud13, snip1 (pml1) and rbmx2 (snu17) mutants revealed a global defect in intron splicing, with strong mis-splicing of a subset of introns. We found these RES-dependent introns were short, rich in GC and flanked by GC depleted exons, all of which are features associated with intron definition. Using these features, we developed and validated a predictive model that classifies RES dependent introns. Altogether, our study uncovers the essential role of the RES complex during vertebrate development and provides new insights into its function during splicing.
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Affiliation(s)
- Juan Pablo Fernandez
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States of America
| | | | - Andre Gohr
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST); Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Liyun Miao
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States of America
| | - Shun Hang Chan
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States of America
| | - Manuel Irimia
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST); Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Antonio J. Giraldez
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States of America
- Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, United States of America
- Yale Cancer Center, Yale University School of Medicine, New Haven, CT, United States of America
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19
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Liss M, Radke MH, Eckhard J, Neuenschwander M, Dauksaite V, von Kries JP, Gotthardt M. Drug discovery with an RBM20 dependent titin splice reporter identifies cardenolides as lead structures to improve cardiac filling. PLoS One 2018; 13:e0198492. [PMID: 29889873 PMCID: PMC5995442 DOI: 10.1371/journal.pone.0198492] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/20/2018] [Indexed: 02/07/2023] Open
Abstract
Diastolic dysfunction is increasingly prevalent in our ageing society and an important contributor to heart failure. The giant protein titin could serve as a therapeutic target, as its elastic properties are a main determinant of cardiac filling in diastole. This study aimed to develop a high throughput pharmacological screen to identify small molecules that affect titin isoform expression through differential inclusion of exons encoding the elastic PEVK domains. We used a dual luciferase splice reporter assay that builds on the titin splice factor RBM20 to screen ~34,000 small molecules and identified several compounds that inhibit the exclusion of PEVK exons. These compounds belong to the class of cardenolides and affect RBM20 dependent titin exon exclusion but did not affect RBFOX1 mediated splicing of FMNL3. We provide evidence that cardenolides do not bind to the RNA interacting domain of RBM20, but reduce RBM20 protein levels and alter transcription of select splicing factors that interact with RBM20. Cardenolides affect titin isoform expression. Understanding their mode of action and harnessing the splice effects through chemical modifications that suppress the effects on ion homeostasis and more selectively affect cardiac splicing has the potential to improve cardiac filling and thus help patients with diastolic heart failure, for which currently no targeted therapy exists.
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Affiliation(s)
- Martin Liss
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Michael H. Radke
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Jamina Eckhard
- Screening Unit, Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | | | - Vita Dauksaite
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | | | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- * E-mail:
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20
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Nakka K, Ghigna C, Gabellini D, Dilworth FJ. Diversification of the muscle proteome through alternative splicing. Skelet Muscle 2018; 8:8. [PMID: 29510724 PMCID: PMC5840707 DOI: 10.1186/s13395-018-0152-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/15/2018] [Indexed: 12/16/2022] Open
Abstract
Background Skeletal muscles express a highly specialized proteome that allows the metabolism of energy sources to mediate myofiber contraction. This muscle-specific proteome is partially derived through the muscle-specific transcription of a subset of genes. Surprisingly, RNA sequencing technologies have also revealed a significant role for muscle-specific alternative splicing in generating protein isoforms that give specialized function to the muscle proteome. Main body In this review, we discuss the current knowledge with respect to the mechanisms that allow pre-mRNA transcripts to undergo muscle-specific alternative splicing while identifying some of the key trans-acting splicing factors essential to the process. The importance of specific splicing events to specialized muscle function is presented along with examples in which dysregulated splicing contributes to myopathies. Though there is now an appreciation that alternative splicing is a major contributor to proteome diversification, the emergence of improved “targeted” proteomic methodologies for detection of specific protein isoforms will soon allow us to better appreciate the extent to which alternative splicing modifies the activity of proteins (and their ability to interact with other proteins) in the skeletal muscle. In addition, we highlight a continued need to better explore the signaling pathways that contribute to the temporal control of trans-acting splicing factor activity to ensure specific protein isoforms are expressed in the proper cellular context. Conclusions An understanding of the signal-dependent and signal-independent events driving muscle-specific alternative splicing has the potential to provide us with novel therapeutic strategies to treat different myopathies. Electronic supplementary material The online version of this article (10.1186/s13395-018-0152-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kiran Nakka
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Claudia Ghigna
- Istituto di Genetica Molecolare-Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia, Italy
| | - Davide Gabellini
- Unit of Gene Expression and Muscular Dystrophy, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, DIBIT2, 5A3-44, via Olgettina 58, 20132, Milan, Italy.
| | - F Jeffrey Dilworth
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada. .,Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, 501 Smyth Rd, Mailbox 511, Ottawa, ON, K1H 8L6, Canada.
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21
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Molecular basis of differential 3' splice site sensitivity to anti-tumor drugs targeting U2 snRNP. Nat Commun 2017; 8:2100. [PMID: 29235465 PMCID: PMC5727392 DOI: 10.1038/s41467-017-02007-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/30/2017] [Indexed: 01/21/2023] Open
Abstract
Several splicing-modulating compounds, including Sudemycins and Spliceostatin A, display anti-tumor properties. Combining transcriptome, bioinformatic and mutagenesis analyses, we delineate sequence determinants of the differential sensitivity of 3′ splice sites to these drugs. Sequences 5′ from the branch point (BP) region strongly influence drug sensitivity, with additional functional BPs reducing, and BP-like sequences allowing, drug responses. Drug-induced retained introns are typically shorter, displaying higher GC content and weaker polypyrimidine-tracts and BPs. Drug-induced exon skipping preferentially affects shorter alternatively spliced regions with weaker BPs. Remarkably, structurally similar drugs display both common and differential effects on splicing regulation, SSA generally displaying stronger effects on intron retention, and Sudemycins more acute effects on exon skipping. Collectively, our results illustrate how splicing modulation is exquisitely sensitive to the sequence context of 3′ splice sites and to small structural differences between drugs. Several families of natural compounds target core components of the pre-mRNA splicing machinery and display anti-tumor activity. Here the authors show that particular sequence features can be linked to drug response, and that drugs with very similar chemical structures display substantially different effects on splicing regulation.
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22
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Chen L, Weinmeister R, Kralovicova J, Eperon LP, Vorechovsky I, Hudson AJ, Eperon IC. Stoichiometries of U2AF35, U2AF65 and U2 snRNP reveal new early spliceosome assembly pathways. Nucleic Acids Res 2017; 45:2051-2067. [PMID: 27683217 PMCID: PMC5389562 DOI: 10.1093/nar/gkw860] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/16/2016] [Indexed: 12/24/2022] Open
Abstract
The selection of 3΄ splice sites (3΄ss) is an essential early step in mammalian RNA splicing reactions, but the processes involved are unknown. We have used single molecule methods to test whether the major components implicated in selection, the proteins U2AF35 and U2AF65 and the U2 snRNP, are able to recognize alternative candidate sites or are restricted to one pre-specified site. In the presence of adenosine triphosphate (ATP), all three components bind in a 1:1 stoichiometry with a 3΄ss. Pre-mRNA molecules with two alternative 3΄ss can be bound concurrently by two molecules of U2AF or two U2 snRNPs, so none of the components are restricted. However, concurrent occupancy inhibits splicing. Stoichiometric binding requires conditions consistent with coalescence of the 5΄ and 3΄ sites in a complex (I, initial), but if this cannot form the components show unrestricted and stochastic association. In the absence of ATP, when complex E forms, U2 snRNP association is unrestricted. However, if protein dephosphorylation is prevented, an I-like complex forms with stoichiometric association of U2 snRNPs and the U2 snRNA is base-paired to the pre-mRNA. Complex I differs from complex A in that the formation of complex A is associated with the loss of U2AF65 and 35.
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Affiliation(s)
- Li Chen
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Robert Weinmeister
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Lucy P Eperon
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Andrew J Hudson
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Chemistry, Leicester LE1 7RH, UK
| | - Ian C Eperon
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
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23
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Abstract
STAR (signal transduction and activation of RNA) proteins regulate splicing of target genes that have roles in neural connectivity, survival and myelination in the vertebrate nervous system. These regulated splicing targets include mRNAs such as the Neurexins (Nrxn), SMN2 (survival of motor neuron) and MAG (myelin-associated glycoprotein). Recent work has made it possible to identify and validate STAR protein splicing targets in vivo by using genetically modified mouse models. In this review, we will discuss the importance of STAR protein splicing targets in the CNS (central nervous system).
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24
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Chatrikhi R, Wang W, Gupta A, Loerch S, Maucuer A, Kielkopf CL. SF1 Phosphorylation Enhances Specific Binding to U2AF 65 and Reduces Binding to 3'-Splice-Site RNA. Biophys J 2017; 111:2570-2586. [PMID: 28002734 DOI: 10.1016/j.bpj.2016.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/02/2016] [Accepted: 11/08/2016] [Indexed: 12/25/2022] Open
Abstract
Splicing factor 1 (SF1) recognizes 3' splice sites of the major class of introns as a ternary complex with U2AF65 and U2AF35 splicing factors. A conserved SPSP motif in a coiled-coil domain of SF1 is highly phosphorylated in proliferating human cells and is required for cell proliferation. The UHM kinase 1 (UHMK1), also called KIS, double-phosphorylates both serines of this SF1 motif. Here, we use isothermal titration calorimetry to demonstrate that UHMK1 phosphorylation of the SF1 SPSP motif slightly enhances specific binding of phospho-SF1 to its cognate U2AF65 protein partner. Conversely, quantitative fluorescence anisotropy RNA binding assays and isothermal titration calorimetry experiments establish that double-SPSP phosphorylation reduces phospho-SF1 and phospho-SF1-U2AF65 binding affinities for either optimal or suboptimal splice-site RNAs. Domain-substitution and mutagenesis experiments further demonstrate that arginines surrounding the phosphorylated SF1 loop are required for cooperative 3' splice site recognition by the SF1-U2AF65 complex (where cooperativity is defined as a nonadditive increase in RNA binding by the protein complex relative to the individual proteins). In the context of local, intracellular concentrations, the subtle effects of SF1 phosphorylation on its associations with U2AF65 and splice-site RNAs are likely to influence pre-mRNA splicing. However, considering roles for SF1 in pre-mRNA retention and transcriptional repression, as well as in splicing, future comprehensive investigations are needed to fully explain the requirement for SF1 SPSP phosphorylation in proliferating human cells.
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Affiliation(s)
- Rakesh Chatrikhi
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York
| | - Wenhua Wang
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York
| | - Ankit Gupta
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York
| | - Sarah Loerch
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York
| | | | - Clara L Kielkopf
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York.
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25
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Sohail M, Xie J. Diverse regulation of 3' splice site usage. Cell Mol Life Sci 2015; 72:4771-93. [PMID: 26370726 PMCID: PMC11113787 DOI: 10.1007/s00018-015-2037-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/12/2015] [Accepted: 09/03/2015] [Indexed: 01/13/2023]
Abstract
The regulation of splice site (SS) usage is important for alternative pre-mRNA splicing and thus proper expression of protein isoforms in cells; its disruption causes diseases. In recent years, an increasing number of novel regulatory elements have been found within or nearby the 3'SS in mammalian genes. The diverse elements recruit a repertoire of trans-acting factors or form secondary structures to regulate 3'SS usage, mostly at the early steps of spliceosome assembly. Their mechanisms of action mainly include: (1) competition between the factors for RNA elements, (2) steric hindrance between the factors, (3) direct interaction between the factors, (4) competition between two splice sites, or (5) local RNA secondary structures or longer range loops, according to the mode of protein/RNA interactions. Beyond the 3'SS, chromatin remodeling/transcription, posttranslational modifications of trans-acting factors and upstream signaling provide further layers of regulation. Evolutionarily, some of the 3'SS elements seem to have emerged in mammalian ancestors. Moreover, other possibilities of regulation such as that by non-coding RNA remain to be explored. It is thus likely that there are more diverse elements/factors and mechanisms that influence the choice of an intron end. The diverse regulation likely contributes to a more complex but refined transcriptome and proteome in mammals.
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Affiliation(s)
- Muhammad Sohail
- Department of Physiology and Pathophysiology, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada
| | - Jiuyong Xie
- Department of Physiology and Pathophysiology, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
- Department of Biochemistry and Medical Genetics, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
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26
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Crisci A, Raleff F, Bagdiul I, Raabe M, Urlaub H, Rain JC, Krämer A. Mammalian splicing factor SF1 interacts with SURP domains of U2 snRNP-associated proteins. Nucleic Acids Res 2015; 43:10456-73. [PMID: 26420826 PMCID: PMC4666396 DOI: 10.1093/nar/gkv952] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 09/10/2015] [Indexed: 02/03/2023] Open
Abstract
Splicing factor 1 (SF1) recognizes the branch point sequence (BPS) at the 3′ splice site during the formation of early complex E, thereby pre-bulging the BPS adenosine, thought to facilitate subsequent base-pairing of the U2 snRNA with the BPS. The 65-kDa subunit of U2 snRNP auxiliary factor (U2AF65) interacts with SF1 and was shown to recruit the U2 snRNP to the spliceosome. Co-immunoprecipitation experiments of SF1-interacting proteins from HeLa cell extracts shown here are consistent with the presence of SF1 in early splicing complexes. Surprisingly almost all U2 snRNP proteins were found associated with SF1. Yeast two-hybrid screens identified two SURP domain-containing U2 snRNP proteins as partners of SF1. A short, evolutionarily conserved region of SF1 interacts with the SURP domains, stressing their role in protein–protein interactions. A reduction of A complex formation in SF1-depleted extracts could be rescued with recombinant SF1 containing the SURP-interaction domain, but only partial rescue was observed with SF1 lacking this sequence. Thus, SF1 can initially recruit the U2 snRNP to the spliceosome during E complex formation, whereas U2AF65 may stabilize the association of the U2 snRNP with the spliceosome at later times. In addition, these findings may have implications for alternative splicing decisions.
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Affiliation(s)
- Angela Crisci
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Flore Raleff
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Ivona Bagdiul
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Monika Raabe
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, D-37075 Göttingen, Germany
| | | | - Angela Krämer
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
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27
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Brooks AN, Duff MO, May G, Yang L, Bolisetty M, Landolin J, Wan K, Sandler J, Booth BW, Celniker SE, Graveley BR, Brenner SE. Regulation of alternative splicing in Drosophila by 56 RNA binding proteins. Genome Res 2015; 25:1771-80. [PMID: 26294686 PMCID: PMC4617972 DOI: 10.1101/gr.192518.115] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 08/19/2015] [Indexed: 12/26/2022]
Abstract
Alternative splicing is regulated by RNA binding proteins (RBPs) that recognize pre-mRNA sequence elements and activate or repress adjacent exons. Here, we used RNA interference and RNA-seq to identify splicing events regulated by 56 Drosophila proteins, some previously unknown to regulate splicing. Nearly all proteins affected alternative first exons, suggesting that RBPs play important roles in first exon choice. Half of the splicing events were regulated by multiple proteins, demonstrating extensive combinatorial regulation. We observed that SR and hnRNP proteins tend to act coordinately with each other, not antagonistically. We also identified a cross-regulatory network where splicing regulators affected the splicing of pre-mRNAs encoding other splicing regulators. This large-scale study substantially enhances our understanding of recent models of splicing regulation and provides a resource of thousands of exons that are regulated by 56 diverse RBPs.
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Affiliation(s)
- Angela N Brooks
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA; Broad Institute, Cambridge, Massachusetts 02142, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
| | - Michael O Duff
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Gemma May
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Li Yang
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Mohan Bolisetty
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Jane Landolin
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ken Wan
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeremy Sandler
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Benjamin W Booth
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Susan E Celniker
- Department of Genome Dynamics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Steven E Brenner
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA; Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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28
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Kralovicova J, Knut M, Cross NCP, Vorechovsky I. Identification of U2AF(35)-dependent exons by RNA-Seq reveals a link between 3' splice-site organization and activity of U2AF-related proteins. Nucleic Acids Res 2015; 43:3747-63. [PMID: 25779042 PMCID: PMC4402522 DOI: 10.1093/nar/gkv194] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 02/24/2015] [Indexed: 01/05/2023] Open
Abstract
The auxiliary factor of U2 small nuclear RNA (U2AF) is a heterodimer consisting of 65- and 35-kD proteins that bind the polypyrimidine tract (PPT) and AG dinucleotides at the 3′ splice site (3′ss). The gene encoding U2AF35 (U2AF1) is alternatively spliced, giving rise to two isoforms U2AF35a and U2AF35b. Here, we knocked down U2AF35 and each isoform and characterized transcriptomes of HEK293 cells with varying U2AF35/U2AF65 and U2AF35a/b ratios. Depletion of both isoforms preferentially modified alternative RNA processing events without widespread failure to recognize 3′ss or constitutive exons. Over a third of differentially used exons were terminal, resulting largely from the use of known alternative polyadenylation (APA) sites. Intronic APA sites activated in depleted cultures were mostly proximal whereas tandem 3′UTR APA was biased toward distal sites. Exons upregulated in depleted cells were preceded by longer AG exclusion zones and PPTs than downregulated or control exons and were largely activated by PUF60 and repressed by CAPERα. The U2AF(35) repression and activation was associated with a significant interchange in the average probabilities to form single-stranded RNA in the optimal PPT and branch site locations and sequences further upstream. Although most differentially used exons were responsive to both U2AF subunits and their inclusion correlated with U2AF levels, a small number of transcripts exhibited distinct responses to U2AF35a and U2AF35b, supporting the existence of isoform-specific interactions. These results provide new insights into function of U2AF and U2AF35 in alternative RNA processing.
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Affiliation(s)
- Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Marcin Knut
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Nicholas C P Cross
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury SP2 8BJ, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
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Ishizuka A, Hasegawa Y, Ishida K, Yanaka K, Nakagawa S. Formation of nuclear bodies by the lncRNA Gomafu-associating proteins Celf3 and SF1. Genes Cells 2015; 19:704-21. [PMID: 25145264 PMCID: PMC4255692 DOI: 10.1111/gtc.12169] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 06/28/2014] [Indexed: 12/19/2022]
Abstract
Gomafu/MIAT/Rncr2 is a long noncoding RNA that has been proposed to control retinal cell specification, stem cell differentiation and alternative splicing of schizophrenia-related genes. However, how Gomafu controls these biological processes at the molecular level has remained largely unknown. In this study, we identified the RNA-binding protein Celf3 as a novel Gomafu-associating protein. Knockdown of Celf3 led to the down-regulation of Gomafu, and cross-link RNA precipitation analysis confirmed specific binding between Celf3 and Gomafu. In the neuroblastoma cell line Neuro2A, Celf3 formed novel nuclear bodies (named CS bodies) that colocalized with SF1, another Gomafu-binding protein. Gomafu, however, was not enriched in the CS bodies; instead, it formed distinct nuclear bodies in separate regions in the nucleus. These observations suggest that Gomafu indirectly modulates the function of the splicing factors SF1 and Celf3 by sequestering these proteins into separate nuclear bodies.
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Affiliation(s)
- Akira Ishizuka
- RNA Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
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30
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Structure-guided U2AF65 variant improves recognition and splicing of a defective pre-mRNA. Proc Natl Acad Sci U S A 2014; 111:17420-5. [PMID: 25422459 DOI: 10.1073/pnas.1412743111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purine interruptions of polypyrimidine (Py) tract splice site signals contribute to human genetic diseases. The essential splicing factor U2AF(65) normally recognizes a Py tract consensus sequence preceding the major class of 3' splice sites. We found that neurofibromatosis- or retinitis pigmentosa-causing mutations in the 5' regions of Py tracts severely reduce U2AF(65) affinity. Conversely, we identified a preferred binding site of U2AF(65) for purine substitutions in the 3' regions of Py tracts. Based on a comparison of new U2AF(65) structures bound to either A- or G-containing Py tracts with previously identified pyrimidine-containing structures, we expected to find that a D231V amino acid change in U2AF(65) would specify U over other nucleotides. We found that the crystal structure of the U2AF(65)-D231V variant confirms favorable packing between the engineered valine and a target uracil base. The D231V amino acid change restores U2AF(65) affinity for two mutated splice sites that cause human genetic diseases and successfully promotes splicing of a defective retinitis pigmentosa-causing transcript. We conclude that reduced U2AF(65) binding is a molecular consequence of disease-relevant mutations, and that a structure-guided U2AF(65) variant is capable of manipulating gene expression in eukaryotic cells.
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Abstract
Sequence-specific RNA-binding proteins (RBPs) bind to pre-mRNA to control alternative splicing, but it is not yet possible to read the 'splicing code' that dictates splicing regulation on the basis of genome sequence. Each alternative splicing event is controlled by multiple RBPs, the combined action of which creates a distribution of alternatively spliced products in a given cell type. As each cell type expresses a distinct array of RBPs, the interpretation of regulatory information on a given RNA target is exceedingly dependent on the cell type. RBPs also control each other's functions at many levels, including by mutual modulation of their binding activities on specific regulatory RNA elements. In this Review, we describe some of the emerging rules that govern the highly context-dependent and combinatorial nature of alternative splicing regulation.
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Affiliation(s)
- Xiang-Dong Fu
- Department of Cellular and Molecular Medicine and Institute for Genomic, Medicine, University of California San Diego, La Jolla, California 92093–0651, USA
| | - Manuel Ares
- Center for Molecular Biology of RNA, and Department of Molecular, Cell, and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
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32
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Gupta SK, Chikne V, Eliaz D, Tkacz ID, Naboishchikov I, Carmi S, Waldman Ben-Asher H, Michaeli S. Two splicing factors carrying serine-arginine motifs, TSR1 and TSR1IP, regulate splicing, mRNA stability, and rRNA processing in Trypanosoma brucei. RNA Biol 2014; 11:715-31. [PMID: 24922194 DOI: 10.4161/rna.29143] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In trypanosomes, mRNAs are processed by trans-splicing; in this process, a common exon, the spliced leader, is added to all mRNAs from a small RNA donor, the spliced leader RNA (SL RNA). However, little is known regarding how this process is regulated. In this study we investigated the function of two serine-arginine-rich proteins, TSR1 and TSR1IP, implicated in trans-splicing in Trypanosoma brucei. Depletion of these factors by RNAi suggested their role in both cis- and trans-splicing. Microarray was used to examine the transcriptome of the silenced cells. The level of hundreds of mRNAs was changed, suggesting that these proteins have a role in regulating only a subset of T. brucei mRNAs. Mass-spectrometry analyses of complexes associated with these proteins suggest that these factors function in mRNA stability, translation, and rRNA processing. We further demonstrate changes in the stability of mRNA as a result of depletion of the two TSR proteins. In addition, rRNA defects were observed under the depletion of U2AF35, TSR1, and TSR1IP, but not SF1, suggesting involvement of SR proteins in rRNA processing.
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Affiliation(s)
- Sachin Kumar Gupta
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
| | - Vaibhav Chikne
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
| | - Dror Eliaz
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
| | - Itai Dov Tkacz
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
| | - Ilana Naboishchikov
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
| | - Shai Carmi
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
| | - Hiba Waldman Ben-Asher
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
| | - Shulamit Michaeli
- The Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute; Bar-Ilan University; Ramat-Gan, Israel
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33
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Jang YH, Park HY, Lee KC, Thu MP, Kim SK, Suh MC, Kang H, Kim JK. A homolog of splicing factor SF1 is essential for development and is involved in the alternative splicing of pre-mRNA in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 78:591-603. [PMID: 24580679 DOI: 10.1111/tpj.12491] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 02/13/2014] [Accepted: 02/19/2014] [Indexed: 05/20/2023]
Abstract
During initial spliceosome assembly, SF1 binds to intron branch points and interacts with U2 snRNP auxiliary factor 65 (U2AF65). Here, we present evidence indicating that AtSF1, the Arabidopsis SF1 homolog, interacts with AtU2AF65a and AtU2AF65b, the Arabidopsis U2AF65 homologs. A mutant allele of AtSF1 (At5g51300) that contains a T-DNA insertion conferred pleiotropic developmental defects, including early flowering and abnormal sensitivity to abscisic acid. An AtSF1 promoter-driven GUS reporter assay showed that AtSF1 promoter activity was temporally and spatially altered, and that full AtSF1 promoter activity required a significant proportion of the coding region. DNA chip analyses showed that only a small proportion of the transcriptome was altered by more than twofold in either direction in the AtSF1 mutant. Expression of the mRNAs of many heat shock proteins was more than fourfold higher in the mutant strain; these mRNAs were among those whose expression was increased most in the mutant strain. An RT-PCR assay revealed an altered alternative splicing pattern for heat shock transcription factor HsfA2 (At2g26150) in the mutant; this altered splicing is probably responsible for the increased expression of the target genes induced by HsfA2. Altered alternative splicing patterns were also detected for the transcripts of other genes in the mutant strain. These results suggest that AtSF1 has functional similarities to its yeast and metazoan counterparts.
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Affiliation(s)
- Yun Hee Jang
- Plant Signaling Network Research Center, School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea
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34
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Zong FY, Fu X, Wei WJ, Luo YG, Heiner M, Cao LJ, Fang Z, Fang R, Lu D, Ji H, Hui J. The RNA-binding protein QKI suppresses cancer-associated aberrant splicing. PLoS Genet 2014; 10:e1004289. [PMID: 24722255 PMCID: PMC3983035 DOI: 10.1371/journal.pgen.1004289] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 02/18/2014] [Indexed: 12/23/2022] Open
Abstract
Lung cancer is the leading cause of cancer-related death worldwide. Aberrant splicing has been implicated in lung tumorigenesis. However, the functional links between splicing regulation and lung cancer are not well understood. Here we identify the RNA-binding protein QKI as a key regulator of alternative splicing in lung cancer. We show that QKI is frequently down-regulated in lung cancer, and its down-regulation is significantly associated with a poorer prognosis. QKI-5 inhibits the proliferation and transformation of lung cancer cells both in vitro and in vivo. Our results demonstrate that QKI-5 regulates the alternative splicing of NUMB via binding to two RNA elements in its pre-mRNA, which in turn suppresses cell proliferation and prevents the activation of the Notch signaling pathway. We further show that QKI-5 inhibits splicing by selectively competing with a core splicing factor SF1 for binding to the branchpoint sequence. Taken together, our data reveal QKI as a critical regulator of splicing in lung cancer and suggest a novel tumor suppression mechanism involving QKI-mediated regulation of the Notch signaling pathway.
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Affiliation(s)
- Feng-Yang Zong
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xing Fu
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Wen-Juan Wei
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ya-Ge Luo
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Monika Heiner
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Li-Juan Cao
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhaoyuan Fang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Rong Fang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Daru Lu
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Institutes for Biomedical Sciences, Fudan University, Shanghai, China
| | - Hongbin Ji
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jingyi Hui
- State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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35
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Circulating MicroRNAs in Plasma of Hepatitis B e Antigen Positive Children Reveal Liver-Specific Target Genes. Int J Hepatol 2014; 2014:791045. [PMID: 25580300 PMCID: PMC4281389 DOI: 10.1155/2014/791045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/19/2014] [Indexed: 12/14/2022] Open
Abstract
Background and Aim. Hepatitis B e antigen positive (HBeAg-positive) children are at high risk of severe complications such as hepatocellular carcinoma and cirrhosis. Liver damage is caused by the host immune response to infected hepatocytes, and we hypothesise that specific microRNAs play a role in this complex interaction between virus and host. The study aimed to identify microRNAs with aberrant plasma expressions in HBeAg-positive children and with liver-specific target genes. Methods. By revisiting our previous screen of microRNA plasma levels in HBeAg-positive and HBeAg-negative children with chronic hepatitis B (CHB) and in healthy controls, candidate microRNAs with aberrant plasma expressions in HBeAg-positive children were identified. MicroRNAs targeting liver-specific genes were selected based on bioinformatics analysis and validated by qRT-PCR using plasma samples from 34 HBeAg-positive, 26 HBeAg-negative, and 60 healthy control children. Results. Thirteen microRNAs showed aberrant plasma expressions in HBeAg-positive children and targeted liver-specific genes. In particular, three microRNAs were upregulated and one was downregulated in HBeAg-positive children compared to HBeAg-negative and healthy control children, which showed equal levels. Conclusion. The identified microRNAs might impact the progression of CHB in children. Functional studies are warranted, however, to elucidate the microRNAs' role in the immunopathogenesis of childhood CHB.
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36
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Zheng S, Damoiseaux R, Chen L, Black DL. A broadly applicable high-throughput screening strategy identifies new regulators of Dlg4 (Psd-95) alternative splicing. Genome Res 2013; 23:998-1007. [PMID: 23636947 PMCID: PMC3668367 DOI: 10.1101/gr.147546.112] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 03/21/2013] [Indexed: 01/17/2023]
Abstract
Most mammalian genes produce multiple mRNA isoforms derived from alternative pre-mRNA splicing, with each alternative exon controlled by a complex network of regulatory factors. The identification of these regulators can be laborious and is usually carried out one factor at a time. We have developed a broadly applicable high-throughput screening method that simultaneously identifies multiple positive and negative regulators of a particular exon. Two minigene reporters were constructed: One produces green fluorescent protein (GFP) from the mRNA including an exon, and red fluorescent protein (RFP) from the mRNA lacking the exon; the other switches these fluorescent products of exon inclusion and exclusion. Combining results from these two reporters eliminates many false positives and greatly enriches for true splicing regulators. After extensive optimization of this method, we performed a gain-of-function screen of 15,779 cDNA clones and identified 40 genes affecting exon 18 of Discs large homolog 4 (Dlg4; also known as post-synaptic density protein 95 [Psd-95]). We confirmed that 28 of the 34 recoverable clones alter reporter splicing in RT-PCR assays. Remarkably, 18 of the identified genes encode splicing factors or RNA binding proteins, including PTBP1, a previously identified regulator of this exon. Loss-of-function experiments examining endogenous Dlg4 transcripts validated the effects of five of eight genes tested in independent cell lines, and two genes were further confirmed to regulate Dlg4 splicing in primary neurons. These results identify multiple new regulators of Dlg4 splicing, and validate an approach to isolating splicing regulators for almost any cassette exon from libraries of cDNAs, shRNAs, or small molecules.
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Affiliation(s)
- Sika Zheng
- Howard Hughes Medical Institute, University of California at Los Angeles, California 90095, USA
| | - Robert Damoiseaux
- Molecular Screening Shared Resource, University of California at Los Angeles, California 90095, USA
| | - Liang Chen
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Douglas L. Black
- Howard Hughes Medical Institute, University of California at Los Angeles, California 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California at Los Angeles, California 90095, USA
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37
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Hall MP, Nagel RJ, Fagg WS, Shiue L, Cline MS, Perriman RJ, Donohue JP, Ares M. Quaking and PTB control overlapping splicing regulatory networks during muscle cell differentiation. RNA (NEW YORK, N.Y.) 2013; 19:627-38. [PMID: 23525800 PMCID: PMC3677278 DOI: 10.1261/rna.038422.113] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 02/20/2013] [Indexed: 05/26/2023]
Abstract
Alternative splicing contributes to muscle development, but a complete set of muscle-splicing factors and their combinatorial interactions are unknown. Previous work identified ACUAA ("STAR" motif) as an enriched intron sequence near muscle-specific alternative exons such as Capzb exon 9. Mass spectrometry of myoblast proteins selected by the Capzb exon 9 intron via RNA affinity chromatography identifies Quaking (QK), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We find that QK promotes inclusion of Capzb exon 9 in opposition to repression by polypyrimidine tract-binding protein (PTB). QK depletion alters inclusion of 406 cassette exons whose adjacent intron sequences are also enriched in ACUAA motifs. During differentiation of myoblasts to myotubes, QK levels increase two- to threefold, suggesting a mechanism for QK-responsive exon regulation. Combined analysis of the PTB- and QK-splicing regulatory networks during myogenesis suggests that 39% of regulated exons are under the control of one or both of these splicing factors. This work provides the first evidence that QK is a global regulator of splicing during muscle development in vertebrates and shows how overlapping splicing regulatory networks contribute to gene expression programs during differentiation.
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38
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Ali M, Broadhurst RW. Solution structure of the QUA1 dimerization domain of pXqua, the Xenopus ortholog of Quaking. PLoS One 2013; 8:e57345. [PMID: 23520467 PMCID: PMC3592866 DOI: 10.1371/journal.pone.0057345] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/21/2013] [Indexed: 11/19/2022] Open
Abstract
The STAR protein family member Quaking is essential for early development in vertebrates. For example, in oligodendrocyte cells it regulates the splicing, localization, translation and lifetime of a set of mRNAs that code for crucial components of myelin. The Quaking protein contains three contiguous conserved regions: a QUA1 oligomerization element, followed by a single-stranded RNA binding motif comprising the KH and QUA2 domains. An embryonic lethal point mutation in the QUA1 domain, E48G, is known to affect both the aggregation state and RNA-binding properties of the murine Quaking ortholog (QKI). Here we report the NMR solution structure of the QUA1 domain from the Xenopus laevis Quaking ortholog (pXqua), which forms a dimer composed of two perpendicularly docked α-helical hairpin motifs. Size exclusion chromatography studies of a range of mutants demonstrate that the dimeric state of the pXqua QUA1 domain is stabilized by a network of interactions between side-chains, with significant roles played by an intra-molecular hydrogen bond between Y41 and E72 (the counterpart to QKI E48) and an inter-protomer salt bridge between E72 and R67. These results are compared with recent structural and mutagenesis studies of QUA1 domains from the STAR family members QKI, GLD-1 and Sam68.
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Affiliation(s)
- Muzaffar Ali
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - R. William Broadhurst
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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39
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Gupta SK, Carmi S, Waldman Ben-Asher H, Tkacz ID, Naboishchikov I, Michaeli S. Basal splicing factors regulate the stability of mature mRNAs in trypanosomes. J Biol Chem 2013; 288:4991-5006. [PMID: 23283975 DOI: 10.1074/jbc.m112.416578] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gene expression in trypanosomes is mainly regulated post-transcriptionally. Genes are transcribed as polycistronic mRNAs that are dissected by the concerted action of trans-splicing and polyadenylation. In trans-splicing, a common exon, the spliced leader, is added to all mRNAs from a small RNA. In this study, we examined by microarray analysis the transcriptome following RNAi silencing of the basal splicing factors U2AF65, SF1, and U2AF35. The transcriptome data revealed correlations between the affected genes and their splicing and polyadenylation signaling properties, suggesting that differential binding of these factors to pre-mRNA regulates trans-splicing and hence expression of specific genes. Surprisingly, all these factors were shown to affect not only splicing but also mRNA stability. Affinity purification of SF1 and U2AF35 complexes supported their role in mRNA stability. U2AF35 but not SF1 was shown to bind to ribosomes. To examine the role of splicing factors in mRNA stability, mutations were introduced into the polypyrimidine tract located in the 3' UTR of a mini-gene, and the results demonstrate that U2AF65 binds to such a site and controls the mRNA stability. We propose that transcripts carrying splicing signals in their 3' UTR bind the splicing factors and control their stability.
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Affiliation(s)
- Sachin Kumar Gupta
- Mina and Everard Goodman Faculty of Life Sciences, and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 52900, Israel
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40
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Zhang Y, Madl T, Bagdiul I, Kern T, Kang HS, Zou P, Mäusbacher N, Sieber SA, Krämer A, Sattler M. Structure, phosphorylation and U2AF65 binding of the N-terminal domain of splicing factor 1 during 3'-splice site recognition. Nucleic Acids Res 2012; 41:1343-54. [PMID: 23175611 PMCID: PMC3553976 DOI: 10.1093/nar/gks1097] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Recognition of the 3'-splice site is a key step in pre-mRNA splicing and accomplished by a dynamic complex comprising splicing factor 1 (SF1) and the U2 snRNP auxiliary factor 65-kDa subunit (U2AF65). Both proteins mediate protein-protein and protein-RNA interactions for cooperative RNA-binding during spliceosome assembly. Here, we report the solution structure of a novel helix-hairpin domain in the N-terminal region of SF1 (SF1(NTD)). The nuclear magnetic resonance- and small-angle X-ray scattering-derived structure of a complex of the SF1(NTD) with the C-terminal U2AF homology motif domain of U2AF65 (U2AF65(UHM)) reveals that, in addition to the known U2AF65(UHM)-SF1 interaction, the helix-hairpin domain forms a secondary, hydrophobic interface with U2AF65(UHM), which locks the orientation of the two subunits. Mutational analysis shows that the helix hairpin is essential for cooperative formation of the ternary SF1-U2AF65-RNA complex. We further show that tandem serine phosphorylation of a conserved Ser80-Pro81-Ser82-Pro83 motif rigidifies a long unstructured linker in the SF1 helix hairpin. Phosphorylation does not significantly alter the overall conformations of SF1, SF1-U2AF65 or the SF1-U2AF65-RNA complexes, but slightly enhances RNA binding. Our results indicate that the helix-hairpin domain of SF1 is required for cooperative 3'-splice site recognition presumably by stabilizing a unique quaternary arrangement of the SF1-U2AF65-RNA complex.
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Affiliation(s)
- Yun Zhang
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
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41
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Pérez-Valle J, Vilardell J. Intronic features that determine the selection of the 3' splice site. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:707-17. [PMID: 22807288 DOI: 10.1002/wrna.1131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Most eukaryotic primary transcripts include segments, or introns, that will be accurately removed during RNA biogenesis. This process, known as pre-messenger RNA splicing, is catalyzed by the spliceosome, accurately selecting a set of intronic marks from others apparently equivalent. This identification is critical, as incorrectly spliced RNAs can be toxic for the organism. One of these marks, the dinucleotide AG, signals the intronic 3' end, or 3' splice site (ss). In this review we will focus on those intronic features that have an impact on 3' ss selection. These include the location and type of neighboring sequences, and their distance to the 3' end. We will see that their interplay is needed to select the right intronic end, and that this can be modulated by additional intronic elements that contribute to alternative splicing, whereby diverse RNAs can be generated from identical precursors. This complexity, still poorly understood, is fundamental for the accuracy of gene expression. In addition, a clear knowledge of 3' ss selection is needed to fully decipher the coding potential of genomes.
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Affiliation(s)
- Jorge Pérez-Valle
- Department of Molecular Genòmics, Institute of Molecular Biology of Barcelona (IBMB), Barcelona, Spain
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42
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Jia Y, Mu JC, Ackerman SL. Mutation of a U2 snRNA gene causes global disruption of alternative splicing and neurodegeneration. Cell 2012; 148:296-308. [PMID: 22265417 DOI: 10.1016/j.cell.2011.11.057] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 08/06/2011] [Accepted: 11/08/2011] [Indexed: 12/30/2022]
Abstract
Although uridine-rich small nuclear RNAs (U-snRNAs) are essential for pre-mRNA splicing, little is known regarding their function in the regulation of alternative splicing or of the biological consequences of their dysfunction in mammals. Here, we demonstrate that mutation of Rnu2-8, one of the mouse multicopy U2 snRNA genes, causes ataxia and neurodegeneration. Coincident with the observed pathology, the level of mutant U2 RNAs was highest in the cerebellum and increased after granule neuron maturation. Furthermore, neuron loss was strongly dependent on the dosage of mutant and wild-type snRNA genes. Comprehensive transcriptome analysis identified a group of alternative splicing events, including the splicing of small introns, which were disrupted in the mutant cerebellum. Our results suggest that the expression of mammalian U2 snRNA genes, previously presumed to be ubiquitous, is spatially and temporally regulated, and dysfunction of a single U2 snRNA causes neuron degeneration through distortion of pre-mRNA splicing.
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Affiliation(s)
- Yichang Jia
- Howard Hughes Medical Institute and The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
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43
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Ankö ML, Neugebauer KM. RNA-protein interactions in vivo: global gets specific. Trends Biochem Sci 2012; 37:255-62. [PMID: 22425269 DOI: 10.1016/j.tibs.2012.02.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/05/2012] [Accepted: 02/08/2012] [Indexed: 01/01/2023]
Abstract
RNA-binding proteins (RBPs) impact every process in the cell; they act as splicing and polyadenylation factors, transport and localization factors, stabilizers and destabilizers, modifiers, and chaperones. RNA-binding capacity can be attributed to numerous protein domains that bind a limited repertoire of short RNA sequences. How is specificity achieved in cells? Here we focus on recent advances in determining the RNA-binding properties of proteins in vivo and compare these to in vitro determinations, highlighting insights into how endogenous RNA molecules are recognized and regulated. We also discuss the crucial contribution of structural determinations for understanding RNA-binding specificity and mechanisms.
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Affiliation(s)
- Minna-Liisa Ankö
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany.
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44
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Abstract
Genome-wide analyses of metazoan transcriptomes have revealed an unexpected level of mRNA diversity that is generated by alternative splicing. Recently, regulatory networks have been identified through which splicing promotes dynamic remodelling of the transcriptome to promote physiological changes, which involve robust and coordinated alternative splicing transitions. The regulation of splicing in yeast, worms, flies and vertebrates affects a variety of biological processes. The functional classes of genes that are regulated by alternative splicing include both those with widespread homeostatic activities and those with cell-type-specific functions. Alternative splicing can drive determinative physiological change or can have a permissive role by providing mRNA variability that is used by other regulatory mechanisms.
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Llorian M, Smith CWJ. Decoding muscle alternative splicing. Curr Opin Genet Dev 2011; 21:380-7. [PMID: 21514141 DOI: 10.1016/j.gde.2011.03.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 03/25/2011] [Indexed: 01/15/2023]
Abstract
Muscle was one of the first tissues in which alternative splicing was widely observed. Cloning and sequencing of muscle-derived cDNAs in the early 1980's revealed that many of the abundant contractile proteins arise by alternative splicing of genes that are more widely expressed. Consequently alternative splicing events in contractile protein genes have long been used as models to dissect the mechanisms of alternative splicing. Transcriptomic and computational analyses have complemented traditional molecular analyses of alternative splicing in muscle and other tissues, illuminating the general underlying principles of coregulated splicing programs. This has culminated in the first attempt to computationally predict tissue-specific changes in splicing. Investigations of myotonic dystrophy (DM), in which CUG expansion RNA leads to misregulated splicing in muscle, have enhanced our understanding of developmentally regulated splicing and led to the development of promising therapeutic strategies based on targeting the toxic RNA repeats.
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Affiliation(s)
- Miriam Llorian
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
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