1
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Shen A, Hencel K, Parker M, Scott R, Skukan R, Adesina A, Metheringham C, Miska E, Nam Y, Haerty W, Simpson G, Akay A. U6 snRNA m6A modification is required for accurate and efficient splicing of C. elegans and human pre-mRNAs. Nucleic Acids Res 2024; 52:9139-9160. [PMID: 38808663 PMCID: PMC11347140 DOI: 10.1093/nar/gkae447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 05/08/2024] [Accepted: 05/28/2024] [Indexed: 05/30/2024] Open
Abstract
pre-mRNA splicing is a critical feature of eukaryotic gene expression. Both cis- and trans-splicing rely on accurately recognising splice site sequences by spliceosomal U snRNAs and associated proteins. Spliceosomal snRNAs carry multiple RNA modifications with the potential to affect different stages of pre-mRNA splicing. Here, we show that the conserved U6 snRNA m6A methyltransferase METT-10 is required for accurate and efficient cis- and trans-splicing of C. elegans pre-mRNAs. The absence of METT-10 in C. elegans and METTL16 in humans primarily leads to alternative splicing at 5' splice sites with an adenosine at +4 position. In addition, METT-10 is required for splicing of weak 3' cis- and trans-splice sites. We identified a significant overlap between METT-10 and the conserved splicing factor SNRNP27K in regulating 5' splice sites with +4A. Finally, we show that editing endogenous 5' splice site +4A positions to +4U restores splicing to wild-type positions in a mett-10 mutant background, supporting a direct role for U6 snRNA m6A modification in 5' splice site recognition. We conclude that the U6 snRNA m6A modification is important for accurate and efficient pre-mRNA splicing.
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Affiliation(s)
- Aykut Shen
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
| | - Katarzyna Hencel
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
| | - Matthew T Parker
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Robyn Scott
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Roberta Skukan
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
| | | | | | - Eric A Miska
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Rd, Cambridge CB2 1QN, UK
| | - Yunsun Nam
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Wilfried Haerty
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
- Earlham Institute, Norwich Research Park, Norwich, UK
| | - Gordon G Simpson
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
- Cell & Molecular Sciences, James Hutton Institute, Invergowrie, DD2 5DA, UK
| | - Alper Akay
- School of Biological Sciences, University of East Anglia, NR4 7TJ Norwich, UK
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2
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Ai Y, Abdel-Wahab O. Splicing regulation of DNA repair via CCAR1. Mol Cell 2024; 84:2591-2592. [PMID: 39059366 DOI: 10.1016/j.molcel.2024.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 06/12/2024] [Accepted: 06/12/2024] [Indexed: 07/28/2024]
Abstract
In this issue of Molecular Cell, Harada et al.1 and Karasu et al.2 identify CCAR1 as a novel regulator of the Fanconi anemia/BRCA DNA repair pathway via modulating the splicing of the mRNA encoding FANCA.
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Affiliation(s)
- Yuxi Ai
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Omar Abdel-Wahab
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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3
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Wang D, Tang M, Zhang P, Yang K, Huang L, Wu M, Shen Q, Yue J, Wang W, Gong Y, Warner M, Dai L, He H, Yang Z, Gustafsson JA, Zhou S. Activation of ERβ hijacks the splicing machinery to trigger R-loop formation in triple-negative breast cancer. Proc Natl Acad Sci U S A 2024; 121:e2306814121. [PMID: 38513102 PMCID: PMC10990146 DOI: 10.1073/pnas.2306814121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 01/23/2024] [Indexed: 03/23/2024] Open
Abstract
Triple-negative breast cancer (TNBC) is a subtype of breast cancer with aggressive behavior and poor prognosis. Current therapeutic options available for TNBC patients are primarily chemotherapy. With our evolving understanding of this disease, novel targeted therapies, including poly ADP-ribose polymerase (PARP) inhibitors, antibody-drug conjugates, and immune-checkpoint inhibitors, have been developed for clinical use. Previous reports have demonstrated the essential role of estrogen receptor β (ERβ) in TNBC, but the detailed molecular mechanisms downstream ERβ activation in TNBC are still far from elucidated. In this study, we demonstrated that a specific ERβ agonist, LY500307, potently induces R-loop formation and DNA damage in TNBC cells. Subsequent interactome experiments indicated that the residues 151 to 165 of U2 small nuclear RNA auxiliary factor 1 (U2AF1) and the Trp439 and Lys443 of ERβ were critical for the binding between U2AF1 and ERβ. Combined RNA sequencing and ribosome sequencing analysis demonstrated that U2AF1-regulated downstream RNA splicing of 5-oxoprolinase (OPLAH) could affect its enzymatic activity and is essential for ERβ-induced R-loop formation and DNA damage. In clinical samples including 115 patients from The Cancer Genome Atlas (TCGA) and 32 patients from an in-house cohort, we found a close correlation in the expression of ESR2 and U2AF1 in TNBC patients. Collectively, our study has unraveled the molecular mechanisms that explain the therapeutic effects of ERβ activation in TNBC, which provides rationale for ERβ activation-based single or combined therapy for patients with TNBC.
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Affiliation(s)
- Dongfang Wang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Muya Tang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Peidong Zhang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Kailin Yang
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH44106
| | - Liang Huang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Mengrui Wu
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Qiuhong Shen
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Jing Yue
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Wei Wang
- Department of Gynecology, Biomedical Big Data Center, Huzhou Maternity and Child Health Care Hospital, Huzhou, Zhejiang313000, People’s Republic of China
| | - Yanqiu Gong
- National Clinical Research Center for Geriatrics and General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu610041, People’s Republic of China
| | - Margaret Warner
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX77204
| | - Lunzhi Dai
- National Clinical Research Center for Geriatrics and General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu610041, People’s Republic of China
| | - Haihuai He
- Department of Neurosurgery, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu610041, People’s Republic of China
| | - Zhengnan Yang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Jan-Ake Gustafsson
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX77204
- Department of Biosciences and Nutrition, Karolinska Institute, Huddinge14157, Sweden
| | - Shengtao Zhou
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education and State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University and Collaborative Innovation Center, Chengdu610041, People’s Republic of China
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4
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Shen A, Hencel K, Parker MT, Scott R, Skukan R, Adesina AS, Metheringham CL, Miska EA, Nam Y, Haerty W, Simpson GG, Akay A. U6 snRNA m6A modification is required for accurate and efficient cis- and trans-splicing of C. elegans mRNAs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.16.558044. [PMID: 37745402 PMCID: PMC10516052 DOI: 10.1101/2023.09.16.558044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
pre-mRNA splicing is a critical feature of eukaryotic gene expression. Many eukaryotes use cis-splicing to remove intronic sequences from pre-mRNAs. In addition to cis-splicing, many organisms use trans-splicing to replace the 5' ends of mRNAs with a non-coding spliced-leader RNA. Both cis- and trans-splicing rely on accurately recognising splice site sequences by spliceosomal U snRNAs and associated proteins. Spliceosomal snRNAs carry multiple RNA modifications with the potential to affect different stages of pre-mRNA splicing. Here, we show that m6A modification of U6 snRNA A43 by the RNA methyltransferase METT-10 is required for accurate and efficient cis- and trans-splicing of C. elegans pre-mRNAs. The absence of U6 snRNA m6A modification primarily leads to alternative splicing at 5' splice sites. Furthermore, weaker 5' splice site recognition by the unmodified U6 snRNA A43 affects splicing at 3' splice sites. U6 snRNA m6A43 and the splicing factor SNRNP27K function to recognise an overlapping set of 5' splice sites with an adenosine at +4 position. Finally, we show that U6 snRNA m6A43 is required for efficient SL trans-splicing at weak 3' trans-splice sites. We conclude that the U6 snRNA m6A modification is important for accurate and efficient cis- and trans-splicing in C. elegans.
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Affiliation(s)
- Aykut Shen
- School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich
| | - Katarzyna Hencel
- School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich
- These authors contributed equally
| | - Matthew T Parker
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
- These authors contributed equally
| | - Robyn Scott
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Roberta Skukan
- School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich
| | | | | | - Eric A Miska
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Rd, Cambridge, CB2 1QN, UK
| | - Yunsun Nam
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Wilfried Haerty
- School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich
- Earlham Institute, Norwich Research Park, Norwich, UK
| | - Gordon G Simpson
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
- Cell & Molecular Sciences, James Hutton Institute, Invergowrie, DD2 5DA, UK
| | - Alper Akay
- School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich
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5
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Yıldırım B, Vogl C. Purifying selection against spurious splicing signals contributes to the base composition evolution of the polypyrimidine tract. J Evol Biol 2023; 36:1295-1312. [PMID: 37564008 PMCID: PMC10946897 DOI: 10.1111/jeb.14205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/31/2023] [Accepted: 06/15/2023] [Indexed: 08/12/2023]
Abstract
Among eukaryotes, the major spliceosomal pathway is highly conserved. While long introns may contain additional regulatory sequences, the ones in short introns seem to be nearly exclusively related to splicing. Although these regulatory sequences involved in splicing are well-characterized, little is known about their evolution. At the 3' end of introns, the splice signal nearly universally contains the dimer AG, which consists of purines, and the polypyrimidine tract upstream of this 3' splice signal is characterized by over-representation of pyrimidines. If the over-representation of pyrimidines in the polypyrimidine tract is also due to avoidance of a premature splicing signal, we hypothesize that AG should be the most under-represented dimer. Through the use of DNA-strand asymmetry patterns, we confirm this prediction in fruit flies of the genus Drosophila and by comparing the asymmetry patterns to a presumably neutrally evolving region, we quantify the selection strength acting on each motif. Moreover, our inference and simulation method revealed that the best explanation for the base composition evolution of the polypyrimidine tract is the joint action of purifying selection against a spurious 3' splice signal and the selection for pyrimidines. Patterns of asymmetry in other eukaryotes indicate that avoidance of premature splicing similarly affects the nucleotide composition in their polypyrimidine tracts.
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Affiliation(s)
- Burçin Yıldırım
- Department of Biomedical SciencesVetmeduni ViennaViennaAustria
- Vienna Graduate School of Population GeneticsViennaAustria
| | - Claus Vogl
- Department of Biomedical SciencesVetmeduni ViennaViennaAustria
- Vienna Graduate School of Population GeneticsViennaAustria
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6
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Hirano M, Galarza-Muñoz G, Nagasawa C, Schott G, Wang L, Antonia AL, Jain V, Yu X, Widen SG, Briggs FBS, Gregory SG, Ko DC, Fagg WS, Bradrick S, Garcia-Blanco MA. The RNA helicase DDX39B activates FOXP3 RNA splicing to control T regulatory cell fate. eLife 2023; 12:e76927. [PMID: 37261960 PMCID: PMC10234631 DOI: 10.7554/elife.76927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 05/09/2023] [Indexed: 06/03/2023] Open
Abstract
Genes associated with increased susceptibility to multiple sclerosis (MS) have been identified, but their functions are incompletely understood. One of these genes codes for the RNA helicase DExD/H-Box Polypeptide 39B (DDX39B), which shows genetic and functional epistasis with interleukin-7 receptor-α gene (IL7R) in MS-risk. Based on evolutionary and functional arguments, we postulated that DDX39B enhances immune tolerance thereby decreasing MS risk. Consistent with such a role we show that DDX39B controls the expression of many MS susceptibility genes and important immune-related genes. Among these we identified Forkhead Box P3 (FOXP3), which codes for the master transcriptional factor in CD4+/CD25+ T regulatory cells. DDX39B knockdown led to loss of immune-regulatory and gain of immune-effector expression signatures. Splicing of FOXP3 introns, which belong to a previously unrecognized type of introns with C-rich polypyrimidine tracts, was exquisitely sensitive to DDX39B levels. Given the importance of FOXP3 in autoimmunity, this work cements DDX39B as an important guardian of immune tolerance.
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Affiliation(s)
- Minato Hirano
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- National Research Center for the Control and Prevention of Infectious Disease, Nagasaki UniversityNagasakiJapan
| | - Gaddiel Galarza-Muñoz
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Autoimmunity Biological SolutionsGalvestonUnited States
| | - Chloe Nagasawa
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Human Pathophysiology and Translational Medicine Program, Institute for Translational Sciences, University of Texas Medical BranchGalvestonUnited States
| | - Geraldine Schott
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
| | - Liuyang Wang
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
| | - Alejandro L Antonia
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
| | - Vaibhav Jain
- Duke Molecular Physiology Institute, Duke UniversityDurhamUnited States
| | - Xiaoying Yu
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Department of Preventive Medicine and Population Health, University of Texas Medical BranchGalvestonUnited States
| | - Steven G Widen
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
| | - Farren BS Briggs
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve UniversityClevelandUnited States
| | - Simon G Gregory
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
- Duke Molecular Physiology Institute, Duke UniversityDurhamUnited States
- Department of Neurology, Duke University School of MedicineDurhamUnited States
| | - Dennis C Ko
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
- Division of Infectious Diseases, Department of Medicine, Duke UniversityDurhamUnited States
| | - William S Fagg
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Transplant Division, Department of Surgery, University of Texas Medical BranchGalvestonUnited States
| | - Shelton Bradrick
- Institute of Human Infections and Immunity, University of Texas Medical BranchGalvestonUnited States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Department of Internal Medicine, University of Texas Medical BranchGalvestonUnited States
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
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7
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Wedge E, Ahmadov U, Hansen TB, Gao Z, Tulstrup M, Côme C, Nonavinkere Srivatsan S, Ahmed T, Jespersen JS, Schlotmann BC, Schöllkopf C, Raaschou-Jensen K, Ødum N, Kjems J, Bak RO, Walter MJ, Grønbæk K, Kristensen LS. Impact of U2AF1 mutations on circular RNA expression in myelodysplastic neoplasms. Leukemia 2023; 37:1113-1125. [PMID: 36922625 DOI: 10.1038/s41375-023-01866-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/16/2023] [Accepted: 02/28/2023] [Indexed: 03/18/2023]
Abstract
Mutations in U2AF1 are relatively common in myelodysplastic neoplasms (MDS) and are associated with an inferior prognosis, but the molecular mechanisms underlying this are not fully elucidated. Circular RNAs (circRNAs) have been implicated in cancer, but it is unknown how mutations in splicing factors may impact on circRNA biogenesis. Here, we used RNA-sequencing to investigate the effects of U2AF1 mutations on circRNA expression in K562 cells with a doxycycline-inducible U2AF1S34 mutation, in a mouse model with a doxycycline-inducible U2AF1S34 mutation, and in FACS-sorted CD34+ bone marrow cells from MDS patients with either U2AF1S34 or U2AF1Q157 mutations. In all contexts, we found an increase in global circRNA levels in the U2AF1-mutated setting, which was independent of expression changes in the cognate linear host genes. In patients, the U2AF1S34 and U2AF1Q157 mutations were both associated with an overall increased expression of circRNAs. circRNAs generated by a non-Alu-mediated mechanism generally showed the largest increase in expression levels. Several well-described cancer-associated circRNAs, including circZNF609 and circCSNK1G3, were upregulated in MDS patients with U2AF1 mutations compared to U2AF1-wildtype MDS controls. In conclusion, high circRNA expression is observed in association with U2AF1 mutations in three biological systems, presenting an interesting possibility for biomarker and therapeutic investigation.
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Affiliation(s)
- Eileen Wedge
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
| | - Ulvi Ahmadov
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Thomas B Hansen
- Department of Molecular Biology and Genetics, Aarhus, Denmark
| | - Zongliang Gao
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Morten Tulstrup
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
| | - Christophe Côme
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
| | | | - Tanzir Ahmed
- Division of Oncology, Washington University School of Medicine, St Louis, MO, USA
| | - Jakob S Jespersen
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
- The Finsen Laboratory, Copenhagen University Hospital, Copenhagen, Denmark
| | - Balthasar C Schlotmann
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
- The Finsen Laboratory, Copenhagen University Hospital, Copenhagen, Denmark
| | - Claudia Schöllkopf
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Niels Ødum
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Kjems
- Department of Molecular Biology and Genetics, Aarhus, Denmark
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Rasmus O Bak
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Matthew J Walter
- Division of Oncology, Washington University School of Medicine, St Louis, MO, USA
| | - Kirsten Grønbæk
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark.
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark.
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark.
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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8
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Regulation of Arp5 expression by alternative splicing coupled to nonsense-mediated RNA decay. Biochem Biophys Res Commun 2023; 657:50-58. [PMID: 36977368 DOI: 10.1016/j.bbrc.2023.03.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 03/19/2023]
Abstract
Actin-related protein 5 (ARP5) inhibits the differentiation of skeletal, smooth, and cardiac muscle tissues, and ARP5 expression increases or decreases according to physiological and pathological changes in the muscle differentiation status. However, the regulatory mechanisms of ARP5 expression are largely unknown. Here, we identified a novel Arp5 mRNA isoform that contains premature termination codons in alternative exon 7b and is thus targeted by nonsense-mediated mRNA decay (NMD). In mouse skeletal muscle cells, switching from the canonical Arp5 isoform, i.e., Arp5(7a), to the NMD-targeted isoform Arp5(7b) occurred during differentiation, suggesting that Arp5 expression is regulated by alternative splicing coupled to NMD (AS-NMD). We developed an original method to accurately quantify the proportion of both Arp5 isoforms and measured higher levels of Arp5(7b) in muscle and brain tissues, where ARP5 is less expressed. The 3' splice site in Arp5 exon 7 has an unusual acceptor sequence that often leads to the skip of the authentic splice site and the use of the cryptic splice site localized 16 bases downstream. When the unusual acceptor sequence was mutated to the usual one, the Arp5(7b) isoform was barely detectable. The expression of several splicing factors involved in 3' splice site recognition was reduced after muscle differentiation. Additionally, knockdown of splicing factors increased the levels of Arp5(7b) and decreased the expression of Arp5(7a). Furthermore, strong positive correlations were found between Arp5 expression and the levels of these splicing factors in human skeletal and cardiac muscle tissues. Thus, Arp5 expression in muscle tissues is most likely regulated by the AS-NMD pathway.
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9
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González-Rodríguez P, Klionsky DJ, Joseph B. Autophagy regulation by RNA alternative splicing and implications in human diseases. Nat Commun 2022; 13:2735. [PMID: 35585060 PMCID: PMC9117662 DOI: 10.1038/s41467-022-30433-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/29/2022] [Indexed: 02/06/2023] Open
Abstract
Autophagy and RNA alternative splicing are two evolutionarily conserved processes involved in overlapping physiological and pathological processes. However, the extent of functional connection is not well defined. Here, we consider the role for alternative splicing and generation of autophagy-related gene isoforms in the regulation of autophagy in recent work. The impact of changes to the RNA alternative splicing machinery and production of alternative spliced isoforms on autophagy are reviewed with particular focus on disease relevance. The use of drugs targeting both alternative splicing and autophagy as well as the selective regulation of single autophagy-related protein isoforms, are considered as therapeutic strategies.
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Affiliation(s)
- Patricia González-Rodríguez
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institutet, Stockholm, Sweden
- Division of Biochemistry, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Daniel J Klionsky
- Life Sciences Institute, Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Bertrand Joseph
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institutet, Stockholm, Sweden.
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10
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UHMK1 aids colorectal cancer cell proliferation and chemoresistance through augmenting IL-6/STAT3 signaling. Cell Death Dis 2022; 13:424. [PMID: 35501324 PMCID: PMC9061793 DOI: 10.1038/s41419-022-04877-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/15/2022] [Accepted: 04/21/2022] [Indexed: 12/14/2022]
Abstract
UHMK1, a serine/threonine kinase with a U2AF homology motif, is implicated in RNA processing and protein phosphorylation. Increasing evidence has indicated its involvement in tumorigenesis. However, it remains to be elucidated whether UHMK1 plays a role in the development of colorectal cancer (CRC). Here, we demonstrated that UHMK1 was frequently upregulated in CRC samples compared with adjacent normal tissue and high expression of UHMK1 predicted poor outcomes. Knockdown of UHMK1 by siRNAs restrained CRC cell proliferation and increased oxaliplatin sensitivity, whereas overexpression of UHMK1 promoted CRC cell growth and oxaliplatin resistance, suggesting that UHMK1 plays important oncogenic roles in CRC. Mechanistically, we showed that UHMK1 had a significant effect on IL6/STAT3 signaling by interacting with STAT3. The interaction of UHMK1 with STAT3 enhanced STAT3 activity in regulating gene transcription. Furthermore, we found that STAT3 could in turn transcriptionally activate UHMK1 expression in CRC cells. The complementary experiments for cell growth and oxaliplatin resistance indicated the interdependent relationship between UHMK1 and STAT3. Thus, these collective findings uncovered a new UHMK1/STAT3 positive feedback regulatory loop contributing to CRC development and chemoresistance.
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11
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Lu S, Gao C, Wang Y, He Y, Du J, Chen M, Zhao H, Fang H, Wang B, Cao Y. Phylogenetic Analysis of the Plant U2 snRNP Auxiliary Factor Large Subunit A Gene Family in Response to Developmental Cues and Environmental Stimuli. FRONTIERS IN PLANT SCIENCE 2021; 12:739671. [PMID: 34868124 PMCID: PMC8635922 DOI: 10.3389/fpls.2021.739671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
In all organisms, splicing occurs through the formation of spliceosome complexes, and splicing auxiliary factors are essential during splicing. U2AF65 is a crucial splicing cofactor, and the two typical RNA-recognition motifs at its center recognize and bind the polypyrimidine sequence located between the intron branch site and the 3'-splice site. U2AF65A is a member of the U2AF65 gene family, with pivotal roles in diseases in mammals, specifically humans; however, few studies have investigated plant U2AF65A, and its specific functions are poorly understood. Therefore, in the present study, we systematically identified U2AF65A in plant species from algae to angiosperms. Based on 113 putative U2AF65A sequences from 33 plant species, phylogenetic analyses were performed, followed by basic bioinformatics, including the comparisons of gene structure, protein domains, promoter motifs, and gene expression levels. In addition, using rice as the model crop, we demonstrated that the OsU2AF65A protein is localized to the nucleus and cytoplasm, and it is involved in responses to various stresses, such as drought, high salinity, low temperature, and heavy metal exposure (e.g., cadmium). Using Arabidopsis thaliana and rice mutants, we demonstrated that U2AF65A is involved in the accumulation of plant biomass, growth of hypocotyl upon thermal stimulation, and reduction of tolerance of high temperature stress. These findings offer an overview of the U2AF65 gene family and its stress response functions, serving as the reference for further comprehensive functional studies of the essential specific splicing cofactor U2AF65A in the plant kingdom.
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Affiliation(s)
- Shuai Lu
- School of Life Sciences, Nantong University, Nantong, China
| | - Cong Gao
- School of Life Sciences, Nantong University, Nantong, China
| | - Yongzhou Wang
- School of Life Sciences, Nantong University, Nantong, China
| | - Yingying He
- School of Life Sciences, Nantong University, Nantong, China
| | - Junrong Du
- School of Life Sciences, Nantong University, Nantong, China
| | - Moxian Chen
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Hua Zhao
- School of Life Sciences, Nantong University, Nantong, China
| | - Hui Fang
- School of Life Sciences, Nantong University, Nantong, China
| | - Baohua Wang
- School of Life Sciences, Nantong University, Nantong, China
| | - Yunying Cao
- School of Life Sciences, Nantong University, Nantong, China
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12
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Zhao Z, Xu Q, Wei R, Wang W, Ding D, Yang Y, Yao J, Zhang L, Hu YQ, Wei G, Ni T. Cancer-associated dynamics and potential regulators of intronic polyadenylation revealed by IPAFinder using standard RNA-seq data. Genome Res 2021; 31:2095-2106. [PMID: 34475268 PMCID: PMC8559711 DOI: 10.1101/gr.271627.120] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 08/31/2021] [Indexed: 12/19/2022]
Abstract
Intronic polyadenylation (IpA) usually leads to changes in the coding region of an mRNA, and its implication in diseases has been recognized, although at its very beginning status. Conveniently and accurately identifying IpA is of great importance for further evaluating its biological significance. Here, we developed IPAFinder, a bioinformatic method for the de novo identification of intronic poly(A) sites and their dynamic changes from standard RNA-seq data. Applying IPAFinder to 256 pan-cancer tumor/normal pairs across six tumor types, we discovered 490 recurrent dynamically changed IpA events, some of which are novel and derived from cancer-associated genes such as TSC1, SPERD2, and CCND2. Furthermore, IPAFinder revealed that IpA could be regulated by factors related to splicing and m6A modification. In summary, IPAFinder enables the global discovery and characterization of biologically regulated IpA with standard RNA-seq data and should reveal the biological significance of IpA in various processes.
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Affiliation(s)
- Zhaozhao Zhao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Qiushi Xu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Ran Wei
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Weixu Wang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Dong Ding
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Yu Yang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Jun Yao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Liye Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 200438, P.R. China
| | - Yue-Qing Hu
- State Key Laboratory of Genetic Engineering, Institute of Biostatistics, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Gang Wei
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
| | - Ting Ni
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Human Phenome Institute, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai 200438, P.R. China
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13
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Kataoka N, Matsumoto E, Masaki S. Mechanistic Insights of Aberrant Splicing with Splicing Factor Mutations Found in Myelodysplastic Syndromes. Int J Mol Sci 2021; 22:ijms22157789. [PMID: 34360561 PMCID: PMC8346168 DOI: 10.3390/ijms22157789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 12/22/2022] Open
Abstract
Pre-mRNA splicing is an essential process for gene expression in higher eukaryotes, which requires a high order of accuracy. Mutations in splicing factors or regulatory elements in pre-mRNAs often result in many human diseases. Myelodysplastic syndrome (MDS) is a heterogeneous group of chronic myeloid neoplasms characterized by many symptoms and a high risk of progression to acute myeloid leukemia. Recent findings indicate that mutations in splicing factors represent a novel class of driver mutations in human cancers and affect about 50% of Myelodysplastic syndrome (MDS) patients. Somatic mutations in MDS patients are frequently found in genes SF3B1, SRSF2, U2AF1, and ZRSR2. Interestingly, they are involved in the recognition of 3' splice sites and exons. It has been reported that mutations in these splicing regulators result in aberrant splicing of many genes. In this review article, we first describe molecular mechanism of pre-mRNA splicing as an introduction and mainly focus on those four splicing factors to describe their mutations and their associated aberrant splicing patterns.
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Affiliation(s)
- Naoyuki Kataoka
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan;
- Correspondence: ; Tel.: +81-3-5841-5372; Fax: +81-3-5841-8014
| | - Eri Matsumoto
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan;
| | - So Masaki
- Laboratory of Molecular Medicinal Science, Department of Pharmaceutical Sciences, Ritsumeikan University, Shiga 525-8577, Japan;
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14
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Putscher E, Hecker M, Fitzner B, Lorenz P, Zettl UK. Principles and Practical Considerations for the Analysis of Disease-Associated Alternative Splicing Events Using the Gateway Cloning-Based Minigene Vectors pDESTsplice and pSpliceExpress. Int J Mol Sci 2021; 22:5154. [PMID: 34068052 PMCID: PMC8152502 DOI: 10.3390/ijms22105154] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/23/2022] Open
Abstract
Splicing is an important RNA processing step. Genetic variations can alter the splicing process and thereby contribute to the development of various diseases. Alterations of the splicing pattern can be examined by gene expression analyses, by computational tools for predicting the effects of genetic variants on splicing, and by splicing reporter minigene assays for studying alternative splicing events under defined conditions. The minigene assay is based on transient transfection of cells with a vector containing a genomic region of interest cloned between two constitutive exons. Cloning can be accomplished by the use of restriction enzymes or by site-specific recombination using Gateway cloning. The vectors pDESTsplice and pSpliceExpress represent two minigene systems based on Gateway cloning, which are available through the Addgene plasmid repository. In this review, we describe the features of these two splicing reporter minigene systems. Moreover, we provide an overview of studies in which determinants of alternative splicing were investigated by using pDESTsplice or pSpliceExpress. The studies were reviewed with regard to the investigated splicing regulatory events and the experimental strategy to construct and perform a splicing reporter minigene assay. We further elaborate on how analyses on the regulation of RNA splicing offer promising prospects for gaining important insights into disease mechanisms.
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Affiliation(s)
- Elena Putscher
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
| | - Michael Hecker
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
| | - Brit Fitzner
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
| | - Peter Lorenz
- Rostock University Medical Center, Institute of Immunology, Schillingallee 70, 18057 Rostock, Germany;
| | - Uwe Klaus Zettl
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Street 20, 18147 Rostock, Germany; (E.P.); (B.F.); (U.K.Z.)
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15
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Bedi K, Magnuson BR, Narayanan I, Paulsen M, Wilson TE, Ljungman M. Co-transcriptional splicing efficiencies differ within genes and between cell types. RNA (NEW YORK, N.Y.) 2021; 27:rna.078662.120. [PMID: 33975916 PMCID: PMC8208053 DOI: 10.1261/rna.078662.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/05/2021] [Indexed: 06/01/2023]
Abstract
Pre-mRNA splicing is carried out by the spliceosome and involves splice site recognition, removal of introns, and ligation of exons. Components of the spliceosome have been shown to interact with the elongating RNA polymerase II (RNAPII) which is thought to allow splicing to occur concurrently with transcription. However, little is known about the regulation and efficiency of co-transcriptional splicing in human cells. In this study, we used Bru-seq and BruChase-seq to determine the co-transcriptional splicing efficiencies of 17,000 introns expressed across 6 human cell lines. We found that less than half of all introns across these 6 cell lines were co-transcriptionally spliced. Splicing efficiencies for individual introns showed variations across cell lines, suggesting that splicing may be regulated in a cell-type specific manner. Moreover, the splicing efficiency of introns varied within genes. The efficiency of co-transcriptional splicing did not correlate with gene length, intron position, splice site strengths, or the intron/neighboring exons GC content. However, we identified binding signals from multiple RNA binding proteins (RBPs) that correlated with splicing efficiency, including core spliceosomal machinery components-such as SF3B4, U2AF1 and U2AF2 showing higher binding signals in poorly spliced introns. In addition, multiple RBPs, such as BUD13, PUM1 and SND1, showed preferential binding in exons that flank introns with high splicing efficiencies. The nascent RNA splicing patterns presented here across multiple cell types add to our understanding of the complexity in RNA splicing, wherein RNA-binding proteins may play important roles in determining splicing outcomes in a cell type- and intron-specific manner.
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16
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Mendel M, Delaney K, Pandey RR, Chen KM, Wenda JM, Vågbø CB, Steiner FA, Homolka D, Pillai RS. Splice site m 6A methylation prevents binding of U2AF35 to inhibit RNA splicing. Cell 2021; 184:3125-3142.e25. [PMID: 33930289 PMCID: PMC8208822 DOI: 10.1016/j.cell.2021.03.062] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 02/16/2021] [Accepted: 03/30/2021] [Indexed: 02/06/2023]
Abstract
The N6-methyladenosine (m6A) RNA modification is used widely to alter the fate of mRNAs. Here we demonstrate that the C. elegans writer METT-10 (the ortholog of mouse METTL16) deposits an m6A mark on the 3′ splice site (AG) of the S-adenosylmethionine (SAM) synthetase pre-mRNA, which inhibits its proper splicing and protein production. The mechanism is triggered by a rich diet and acts as an m6A-mediated switch to stop SAM production and regulate its homeostasis. Although the mammalian SAM synthetase pre-mRNA is not regulated via this mechanism, we show that splicing inhibition by 3′ splice site m6A is conserved in mammals. The modification functions by physically preventing the essential splicing factor U2AF35 from recognizing the 3′ splice site. We propose that use of splice-site m6A is an ancient mechanism for splicing regulation. m6A deposited at 3′ splice site by worm METT-10 inhibits splicing Methylation blocks 3′ splice site recognition by splicing factor U2AF35 Methylation and splicing inhibition is a response to change in worm diet Splicing inhibition by 3′ splice site m6A is conserved in mammals
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Affiliation(s)
- Mateusz Mendel
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Kamila Delaney
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Radha Raman Pandey
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Kuan-Ming Chen
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Joanna M Wenda
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Cathrine Broberg Vågbø
- Proteomics and Modomics Experimental Core (PROMEC), Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU) and St. Olavs Hospital Central Staff, Trondheim, Norway
| | - Florian A Steiner
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - David Homolka
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
| | - Ramesh S Pillai
- Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
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17
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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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18
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Morais P, Adachi H, Yu YT. Spliceosomal snRNA Epitranscriptomics. Front Genet 2021; 12:652129. [PMID: 33737950 PMCID: PMC7960923 DOI: 10.3389/fgene.2021.652129] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/08/2021] [Indexed: 12/15/2022] Open
Abstract
Small nuclear RNAs (snRNAs) are critical components of the spliceosome that catalyze the splicing of pre-mRNA. snRNAs are each complexed with many proteins to form RNA-protein complexes, termed as small nuclear ribonucleoproteins (snRNPs), in the cell nucleus. snRNPs participate in pre-mRNA splicing by recognizing the critical sequence elements present in the introns, thereby forming active spliceosomes. The recognition is achieved primarily by base-pairing interactions (or nucleotide-nucleotide contact) between snRNAs and pre-mRNA. Notably, snRNAs are extensively modified with different RNA modifications, which confer unique properties to the RNAs. Here, we review the current knowledge of the mechanisms and functions of snRNA modifications and their biological relevance in the splicing process.
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Affiliation(s)
| | - Hironori Adachi
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, United States
| | - Yi-Tao Yu
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, United States
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19
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Schott G, Galarza-Muñoz G, Trevino N, Chen X, Weirauch M, Gregory SG, Bradrick SS, Garcia-Blanco MA. U2AF2 binds IL7R exon 6 ectopically and represses its inclusion. RNA (NEW YORK, N.Y.) 2021; 27:rna.078279.120. [PMID: 33568552 PMCID: PMC8051268 DOI: 10.1261/rna.078279.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/02/2021] [Indexed: 06/03/2023]
Abstract
Interleukin 7 receptor α-chain is crucial for the development and maintenance of T cells and is genetically associated with autoimmune disorders including multiple sclerosis (MS), a demyelinating disease of the CNS. Exon 6 of IL7R encodes for the transmembrane domain of the receptor and is regulated by alternative splicing: inclusion or skipping of IL7R exon 6 results in membrane-bound or soluble IL7R isoforms, respectively. We previously identified a SNP (rs6897932) in IL7R exon 6, strongly associated with MS risk and showed that the risk allele (C) increases skipping of the exon, resulting in elevated levels of sIL7R. This has important pathological consequences as elevated levels of sIL7R has been shown to exacerbate the disease in the experimental autoimmune encephalomyelitis mouse model of MS. Understanding the regulation of exon 6 splicing provides important mechanistic insights into the pathogenesis of MS. Here we report two mechanisms by which IL7R exon 6 is controlled. First, a competition between PTBP1 and U2AF2 at the polypyrimidine tract (PPT) of intron 5, and second, an unexpected U2AF2-mediated assembly of spicing factors in the exon. We noted the presence of a branchpoint sequence (BPS) (TACTAAT or TACTAAC) within exon 6, which is stronger with the C allele. We also noted that the BPS is followed by a PPT and conjectured that silencing could be mediated by the binding of U2AF2 to that tract. In support of this model, we show that evolutionary conservation of the exonic PPT correlates well with the degree of alternative splicing of exon 6 in two non-human primate species and that U2AF2 binding to this PPT recruits U2 snRNP components to the exon. These observations provide the first explanation for the stronger silencing of IL7R exon 6 with the disease associated C allele at rs6897932.
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20
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U2AF65-Dependent SF3B1 Function in SMN Alternative Splicing. Cells 2020; 9:cells9122647. [PMID: 33317029 PMCID: PMC7762998 DOI: 10.3390/cells9122647] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/05/2020] [Accepted: 12/07/2020] [Indexed: 11/17/2022] Open
Abstract
Splicing factor 3b subunit 1 (SF3B1) is an essential protein in spliceosomes and mutated frequently in many cancers. While roles of SF3B1 in single intron splicing and roles of its cancer-linked mutant in aberrant splicing have been identified to some extent, regulatory functions of wild-type SF3B1 in alternative splicing (AS) are not well-understood yet. Here, we applied RNA sequencing (RNA-seq) to analyze genome-wide AS in SF3B1 knockdown (KD) cells and to identify a large number of skipped exons (SEs), with a considerable number of alternative 5′ splice-site selection, alternative 3′ splice-site selection, mutually exclusive exons (MXE), and retention of introns (RI). Among altered SEs by SF3B1 KD, survival motor neuron 2 (SMN2) pre-mRNA exon 7 splicing was a regulatory target of SF3B1. RT-PCR analysis of SMN exon 7 splicing in SF3B1 KD or overexpressed HCT116, SH-SY5Y, HEK293T, and spinal muscular atrophy (SMA) patient cells validated the results. A deletion mutation demonstrated that the U2 snRNP auxiliary factor 65 kDa (U2AF65) interaction domain of SF3B1 was required for its function in SMN exon 7 splicing. In addition, mutations to lower the score of the polypyrimidine tract (PPT) of exon 7, resulting in lower affinity for U2AF65, were not able to support SF3B1 function, suggesting the importance of U2AF65 in SF3B1 function. Furthermore, the PPT of exon 7 with higher affinity to U2AF65 than exon 8 showed significantly stronger interactions with SF3B1. Collectively, our results revealed SF3B1 function in SMN alternative splicing.
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21
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Hsiao HHT, Crichlow GV, Murphy JW, Folta-Stogniew EJ, Lolis EJ, Braddock DT. Unraveling the mechanism of recognition of the 3' splice site of the adenovirus major late promoter intron by the alternative splicing factor PUF60. PLoS One 2020; 15:e0242725. [PMID: 33253191 PMCID: PMC7703929 DOI: 10.1371/journal.pone.0242725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 11/06/2020] [Indexed: 11/18/2022] Open
Abstract
Pre-mRNA splicing is critical for achieving required amounts of a transcript at a given time and for regulating production of encoded protein. A given pre-mRNA may be spliced in many ways, or not at all, giving rise to multiple gene products. Numerous splicing factors are recruited to pre-mRNA splice sites to ensure proper splicing. One such factor, the 60 kDa poly(U)-binding splicing factor (PUF60), is recruited to sites that are not always spliced, but rather function as alternative splice sites. In this study, we characterized the interaction of PUF60 with a splice site from the adenovirus major late promoter (the AdML 3' splice site, AdML3’). We found that the PUF60–AdML3’ dissociation constants are in the micromolar range, with the binding affinity predominantly provided by PUF60’s two central RNA recognition motifs (RRMs). A 1.95 Å crystal structure of the two PUF60 RRMs in complex with AdML3’ revealed a dimeric organization placing two stretches of nucleic acid tracts in opposing directionalities, which can cause looping of nucleic acid and explain how PUF60 affects pre-mRNA geometry to effect splicing. Solution characterization of this complex by light-scattering and UV/Vis spectroscopy suggested a potential 2:1 (PUF602:AdML3’) stoichiometry, consistent with the crystal structure. This work defines the sequence specificity of the alternative splicing factor PUF60 at the pre-mRNA 3’ splice site. Our observations suggest that control of pre-mRNA directionality is important in the early stage of spliceosome assembly, and advance our understanding of the molecular mechanism by which alternative and constitutive splicing factors differentiate among 3’ splice sites.
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Affiliation(s)
- Hsin-hao T. Hsiao
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Gregg V. Crichlow
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - James W. Murphy
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Ewa J. Folta-Stogniew
- W.M. Keck Biotechnology Research Laboratory, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Elias J. Lolis
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Demetrios T. Braddock
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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22
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Identification of phenothiazine derivatives as UHM-binding inhibitors of early spliceosome assembly. Nat Commun 2020; 11:5621. [PMID: 33159082 PMCID: PMC7648758 DOI: 10.1038/s41467-020-19514-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 10/16/2020] [Indexed: 12/31/2022] Open
Abstract
Interactions between U2AF homology motifs (UHMs) and U2AF ligand motifs (ULMs) play a crucial role in early spliceosome assembly in eukaryotic gene regulation. UHM-ULM interactions mediate heterodimerization of the constitutive splicing factors U2AF65 and U2AF35 and between other splicing factors that regulate spliceosome assembly at the 3′ splice site, where UHM domains of alternative splicing factors, such as SPF45 and PUF60, contribute to alternative splicing regulation. Here, we performed high-throughput screening using fluorescence polarization assays with hit validation by NMR and identified phenothiazines as general inhibitors of UHM-ULM interactions. NMR studies show that these compounds occupy the tryptophan binding pocket of UHM domains. Co-crystal structures of the inhibitors with the PUF60 UHM domain and medicinal chemistry provide structure-activity-relationships and reveal functional groups important for binding. These inhibitors inhibit early spliceosome assembly on pre-mRNA substrates in vitro. Our data show that spliceosome assembly can be inhibited by targeting UHM-ULM interactions by small molecules, thus extending the toolkit of splicing modulators for structural and biochemical studies of the spliceosome and splicing regulation. So far only a few compounds have been reported as splicing modulators. Here, the authors combine high-throughput screening, chemical synthesis, NMR, X-ray crystallography with functional studies and develop phenothiazines as inhibitors for the U2AF Homology Motif (UHM) domains of proteins that regulate splicing and show that they inhibit early spliceosome assembly on pre-mRNA substrates in vitro.
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23
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Goh YT, Koh CWQ, Sim DY, Roca X, Goh WSS. METTL4 catalyzes m6Am methylation in U2 snRNA to regulate pre-mRNA splicing. Nucleic Acids Res 2020; 48:9250-9261. [PMID: 32813009 PMCID: PMC7498333 DOI: 10.1093/nar/gkaa684] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 07/23/2020] [Accepted: 08/04/2020] [Indexed: 01/06/2023] Open
Abstract
N6-methylation of 2′-O-methyladenosine (Am) in RNA occurs in eukaryotic cells to generate N6,2′-O-dimethyladenosine (m6Am). Identification of the methyltransferase responsible for m6Am catalysis has accelerated studies on the function of m6Am in RNA processing. While m6Am is generally found in the first transcribed nucleotide of mRNAs, the modification is also found internally within U2 snRNA. However, the writer required for catalyzing internal m6Am formation had remained elusive. By sequencing transcriptome-wide RNA methylation at single-base-resolution, we identified human METTL4 as the writer that directly methylates Am at U2 snRNA position 30 into m6Am. We found that METTL4 localizes to the nucleus and its conserved methyltransferase catalytic site is required for U2 snRNA methylation. By sequencing human cells with overexpressed Mettl4, we determined METTL4’s in vivo target RNA motif specificity. In the absence of Mettl4 in human cells, U2 snRNA lacks m6Am thereby affecting a subset of splicing events that exhibit specific features such as 3′ splice-site weakness and an increase in exon inclusion. These findings suggest that METTL4 methylation of U2 snRNA regulates splicing of specific pre-mRNA transcripts.
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Affiliation(s)
- Yeek Teck Goh
- Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Casslynn W Q Koh
- Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Donald Yuhui Sim
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xavier Roca
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - W S Sho Goh
- Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
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24
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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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25
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Spliceosomal factor mutations and mis-splicing in MDS. Best Pract Res Clin Haematol 2020; 33:101199. [PMID: 33038983 DOI: 10.1016/j.beha.2020.101199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 02/06/2023]
Abstract
Somatic, heterozygous missense and nonsense mutations in at least seven proteins that function in the spliceosome are found at high frequency in MDS patients. These proteins act at various steps in the process of splicing by the spliceosome and lead to characteristic alterations in the alternative splicing of a subset of genes. Several studies have investigated the effects of these mutations and have attempted to identify a commonly affected gene or pathway. Here, we summarize what is known about the normal function of these proteins and how the mutations alter the splicing landscape of the genome. We also summarize the commonly mis-spliced gene targets and discuss the state of mechanistic unification that has been achieved. Finally, we discuss alternative mechanisms by which these mutations may lead to disease.
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26
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Piña MDLN, Frontera A, Bauzá A. Quantifying Intramolecular Halogen Bonds in Nucleic Acids: A Combined Protein Data Bank and Theoretical Study. ACS Chem Biol 2020; 15:1942-1948. [PMID: 32469201 DOI: 10.1021/acschembio.0c00292] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In this study, we report experimental (Protein Data Bank (PDB) search) and theoretical (RI-MP2/def2-TZVP level of theory) evidence of the nature, stability, and directionality properties of intramolecular halogen bonding interactions (HaBs) between 5-bromo/5-iodoracil bases and backbone phosphate groups in nucleic acids (NAs). A PDB survey revealed relevant examples where intramolecular HaBs are undertaken and serve as a structural source of stability in RNA and DNA molecules. In order to develop suitable energy predictors, we started this investigation by calculating the interaction energy values and both the potential V(r) and kinetic G(r) energy densities (using Bader's "atoms in molecules" theory) of several halogen bond complexes involving 5-bromo/5-iodoracil molecules and biologically relevant electron donors. Once the energy predictors based on V(r)/G(r) energy densities were developed, we analyzed the HaBs observed in the biological examples retrieved from the PDB search in order to estimate the strength of the interaction. As far as our knowledge extends, intramolecular halogen bonds in NAs have not been previously quantified in the literature using this methodology and may be of great importance in understanding their structural properties as well as in the construction of molecular materials with DNA and other biological macromolecules.
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Affiliation(s)
- María de las Nieves Piña
- Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, Palma, Baleares 07122, Spain
| | - Antonio Frontera
- Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, Palma, Baleares 07122, Spain
| | - Antonio Bauzá
- Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, Palma, Baleares 07122, Spain
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27
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Kralovicova J, Borovska I, Kubickova M, Lukavsky PJ, Vorechovsky I. Cancer-Associated Substitutions in RNA Recognition Motifs of PUF60 and U2AF65 Reveal Residues Required for Correct Folding and 3' Splice-Site Selection. Cancers (Basel) 2020; 12:cancers12071865. [PMID: 32664474 PMCID: PMC7408900 DOI: 10.3390/cancers12071865] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/05/2020] [Accepted: 07/07/2020] [Indexed: 12/22/2022] Open
Abstract
U2AF65 (U2AF2) and PUF60 (PUF60) are splicing factors important for recruitment of the U2 small nuclear ribonucleoprotein to lariat branch points and selection of 3′ splice sites (3′ss). Both proteins preferentially bind uridine-rich sequences upstream of 3′ss via their RNA recognition motifs (RRMs). Here, we examined 36 RRM substitutions reported in cancer patients to identify variants that alter 3′ss selection, RNA binding and protein properties. Employing PUF60- and U2AF65-dependent 3′ss previously identified by RNA-seq of depleted cells, we found that 43% (10/23) and 15% (2/13) of independent RRM mutations in U2AF65 and PUF60, respectively, conferred splicing defects. At least three RRM mutations increased skipping of internal U2AF2 (~9%, 2/23) or PUF60 (~8%, 1/13) exons, indicating that cancer-associated RRM mutations can have both cis- and trans-acting effects on splicing. We also report residues required for correct folding/stability of each protein and map functional RRM substitutions on to existing high-resolution structures of U2AF65 and PUF60. These results identify new RRM residues critical for 3′ss selection and provide relatively simple tools to detect clonal RRM mutations that enhance the mRNA isoform diversity.
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Affiliation(s)
- Jana Kralovicova
- Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK;
- Institute of Molecular Physiology and Genetics, Center of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia;
| | - Ivana Borovska
- Institute of Molecular Physiology and Genetics, Center of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia;
| | - Monika Kubickova
- CEITEC, Masaryk University, 625 00 Brno, Czech Republic; (M.K.); (P.J.L.)
| | - Peter J. Lukavsky
- CEITEC, Masaryk University, 625 00 Brno, Czech Republic; (M.K.); (P.J.L.)
| | - Igor Vorechovsky
- Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK;
- Correspondence: ; Tel.: +44-2381-206425; Fax: +44-2381-204264
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28
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Herdt O, Reich S, Medenbach J, Timmermann B, Olofsson D, Preußner M, Heyd F. The zinc finger domains in U2AF26 and U2AF35 have diverse functionalities including a role in controlling translation. RNA Biol 2020; 17:843-856. [PMID: 32116123 DOI: 10.1080/15476286.2020.1732701] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recent work has associated point mutations in both zinc fingers (ZnF) of the spliceosome component U2AF35 with malignant transformation. However, surprisingly little is known about the functionality of the U2AF35 ZnF domains in general. Here we have analysed key functionalities of the ZnF domains of mammalian U2AF35 and its paralog U2AF26. Both ZnFs are required for splicing regulation, whereas only ZnF2 controls protein stability and contributes to the interaction with U2AF65. These features are confirmed in a naturally occurring splice variant of U2AF26 lacking ZnF2, that is strongly induced upon activation of primary mouse T cells and localized in the cytoplasm. Using Ribo-Seq in a model T cell line we provide evidence for a role of U2AF26 in activating cytoplasmic steps in gene expression, notably translation. Consistently, an MS2 tethering assay shows that cytoplasmic U2AF26/35 increase translation when localized to the 5'UTR of a model mRNA. This regulation is partially dependent on ZnF1 thus providing a connection between a core splicing factor, the ZnF domains and the regulation of translation. Altogether, our work reveals unexpected functions of U2AF26/35 and their ZnF domains, thereby contributing to a better understanding of their role and regulation in mammalian cells.
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Affiliation(s)
- Olga Herdt
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin , Berlin, Germany
| | - Stefan Reich
- Institute of Biochemistry I, University of Regensburg , Regensburg, Germany
| | - Jan Medenbach
- Institute of Biochemistry I, University of Regensburg , Regensburg, Germany
| | - Bernd Timmermann
- Sequencing Core Facility, Max-Planck-Institute for Molecular Genetics , Berlin, Germany
| | - Didrik Olofsson
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin , Berlin, Germany
| | - Marco Preußner
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin , Berlin, Germany
| | - Florian Heyd
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin , Berlin, Germany
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29
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Chang JW, Yeh HS, Park M, Erber L, Sun J, Cheng S, Bui AM, Fahmi NA, Nasti R, Kuang R, Chen Y, Zhang W, Yong J. mTOR-regulated U2af1 tandem exon splicing specifies transcriptome features for translational control. Nucleic Acids Res 2019; 47:10373-10387. [PMID: 31504847 PMCID: PMC6821156 DOI: 10.1093/nar/gkz761] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 07/23/2019] [Accepted: 08/23/2019] [Indexed: 01/13/2023] Open
Abstract
U2 auxiliary factor 1 (U2AF1) functions in 3′-splice site selection during pre-mRNA processing. Alternative usage of duplicated tandem exons in U2AF1 produces two isoforms, U2AF1a and U2AF1b, but their functional differences are unappreciated due to their homology. Through integrative approaches of genome editing, customized-transcriptome profiling and crosslinking-mediated interactome analyses, we discovered that the expression of U2AF1 isoforms is controlled by mTOR and they exhibit a distinctive molecular profile for the splice site and protein interactomes. Mechanistic dissection of mutually exclusive alternative splicing events revealed that U2AF1 isoforms’ inherent differential preferences of nucleotide sequences and their stoichiometry determine the 3′-splice site. Importantly, U2AF1a-driven transcriptomes feature alternative splicing events in the 5′-untranslated region (5′-UTR) that are favorable for translation. These findings unveil distinct roles of duplicated tandem exon-derived U2AF1 isoforms in the regulation of the transcriptome and suggest U2AF1a-driven 5′-UTR alternative splicing as a molecular mechanism of mTOR-regulated translational control.
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Affiliation(s)
- Jae-Woong Chang
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Hsin-Sung Yeh
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Meeyeon Park
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Luke Erber
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Jiao Sun
- Department of Computer Science, University of Central Florida, Orlando, FL 32816, USA
| | - Sze Cheng
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Alexander M Bui
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Naima Ahmed Fahmi
- Department of Computer Science, University of Central Florida, Orlando, FL 32816, USA
| | - Ryan Nasti
- Department of Genetics, Cell and Developmental Biology, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Rui Kuang
- Department of Computer Science and Engineering, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Yue Chen
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
| | - Wei Zhang
- Department of Computer Science, University of Central Florida, Orlando, FL 32816, USA
| | - Jeongsik Yong
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA
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30
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Abstract
The spliceosome removes introns from messenger RNA precursors (pre-mRNA). Decades of biochemistry and genetics combined with recent structural studies of the spliceosome have produced a detailed view of the mechanism of splicing. In this review, we aim to make this mechanism understandable and provide several videos of the spliceosome in action to illustrate the intricate choreography of splicing. The U1 and U2 small nuclear ribonucleoproteins (snRNPs) mark an intron and recruit the U4/U6.U5 tri-snRNP. Transfer of the 5' splice site (5'SS) from U1 to U6 snRNA triggers unwinding of U6 snRNA from U4 snRNA. U6 folds with U2 snRNA into an RNA-based active site that positions the 5'SS at two catalytic metal ions. The branch point (BP) adenosine attacks the 5'SS, producing a free 5' exon. Removal of the BP adenosine from the active site allows the 3'SS to bind, so that the 5' exon attacks the 3'SS to produce mature mRNA and an excised lariat intron.
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Affiliation(s)
- Max E Wilkinson
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; ,
| | - Clément Charenton
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; ,
| | - Kiyoshi Nagai
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; ,
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31
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Bretschneider H, Gandhi S, Deshwar AG, Zuberi K, Frey BJ. COSSMO: predicting competitive alternative splice site selection using deep learning. Bioinformatics 2019; 34:i429-i437. [PMID: 29949959 PMCID: PMC6022534 DOI: 10.1093/bioinformatics/bty244] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Motivation Alternative splice site selection is inherently competitive and the probability of a given splice site to be used also depends on the strength of neighboring sites. Here, we present a new model named the competitive splice site model (COSSMO), which explicitly accounts for these competitive effects and predicts the percent selected index (PSI) distribution over any number of putative splice sites. We model an alternative splicing event as the choice of a 3′ acceptor site conditional on a fixed upstream 5′ donor site or the choice of a 5′ donor site conditional on a fixed 3′ acceptor site. We build four different architectures that use convolutional layers, communication layers, long short-term memory and residual networks, respectively, to learn relevant motifs from sequence alone. We also construct a new dataset from genome annotations and RNA-Seq read data that we use to train our model. Results COSSMO is able to predict the most frequently used splice site with an accuracy of 70% on unseen test data, and achieve an R2 of 0.6 in modeling the PSI distribution. We visualize the motifs that COSSMO learns from sequence and show that COSSMO recognizes the consensus splice site sequences and many known splicing factors with high specificity. Availability and implementation Model predictions, our training dataset, and code are available from http://cossmo.genes.toronto.edu. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Hannes Bretschneider
- Deep Genomics Inc, Toronto, Canada.,Department of Computer Science, University of Toronto, Toronto, Canada
| | | | - Amit G Deshwar
- Deep Genomics Inc, Toronto, Canada.,Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
| | | | - Brendan J Frey
- Deep Genomics Inc, Toronto, Canada.,Department of Computer Science, University of Toronto, Toronto, Canada.,Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
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32
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Tari M, Manceau V, de Matha Salone J, Kobayashi A, Pastré D, Maucuer A. U2AF 65 assemblies drive sequence-specific splice site recognition. EMBO Rep 2019; 20:e47604. [PMID: 31271494 PMCID: PMC6681011 DOI: 10.15252/embr.201847604] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 05/21/2019] [Accepted: 05/28/2019] [Indexed: 02/06/2023] Open
Abstract
The essential splicing factor U2AF65 is known to help anchoring U2 snRNP at the branch site. Its C-terminal UHM domain interacts with ULM motifs of SF3b155, an U2 snRNP protein. Here, we report a cooperative binding of U2AF65 and the related protein CAPERα to the multi-ULM domain of SF3b155. In addition, we show that the RS domain of U2AF65 drives a liquid-liquid phase separation that is amplified by intronic RNA with repeated pyrimidine tracts. In cells, knockdown of either U2AF65 or CAPERα improves the inclusion of cassette exons that are preceded by such repeated pyrimidine-rich motifs. These results support a model in which liquid-like assemblies of U2AF65 and CAPERα on repetitive pyrimidine-rich RNA sequences are driven by their RS domains, and facilitate the recruitment of the multi-ULM domain of SF3b155. We anticipate that posttranslational modifications and proteins recruited in dynamical U2AF65 and CAPERα condensates may further contribute to the complex mechanisms leading to specific splice site choice that occurs in cells.
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Affiliation(s)
- Manel Tari
- SABNPUniv EvryINSERM U1204Université Paris‐SaclayEvryFrance
| | - Valérie Manceau
- Institut Necker Enfants Malades (INEM)Inserm U1151 – CNRS UMR 8253Université Paris DescartesParisFrance
- Present address:
Faculty of MedicineInstitut Necker Enfants Malades (INEM)Inserm U1151–CNRS UMR 8253University Paris DescartesSorbonne Paris CitéParisFrance
| | | | | | - David Pastré
- SABNPUniv EvryINSERM U1204Université Paris‐SaclayEvryFrance
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33
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Bartys N, Kierzek R, Lisowiec-Wachnicka J. The regulation properties of RNA secondary structure in alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194401. [PMID: 31323437 DOI: 10.1016/j.bbagrm.2019.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/09/2019] [Indexed: 11/30/2022]
Abstract
The RNA secondary structure is important for many functional processes in the cell. The secondary and tertiary structures of cellular RNAs are essential for the activity of these molecules in processes such as transcription, splicing, translation, and localization. New high-throughput analytical methods, including next generation sequencing, have allowed for the in-depth characterization of the 'RNA structurome': a new term describing how the RNA structure controls the activity of RNA by itself and how it regulates the expression of genes. In this review, we present many examples of the influence of structural motifs of RNA, long range interactions and global RNA structure on the alternative splicing processes. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Natalia Bartys
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Ryszard Kierzek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Jolanta Lisowiec-Wachnicka
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland.
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34
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Activation of Cryptic 3' Splice-Sites by SRSF2 Contributes to Cassette Exon Skipping. Cells 2019; 8:cells8070696. [PMID: 31295920 PMCID: PMC6678912 DOI: 10.3390/cells8070696] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 11/21/2022] Open
Abstract
Here we show that the serine/arginine rich splicing factor 2 (SRSF2) promotes cryptic 3′ splice-site (3′AG′) usage during cassette exon exclusion in survival of motor neuron (SMN2) minigenes. Deletion of the 3′AG′ (3′AG′1), its associated branch point (BP′) and polypyrimidine tract (PPT′) sequences directs SRSF2 to promote a second 3′AG′ (3′AG′2) with less conserved associated region for intron splicing. Furthermore, deletion of both 3′AG′1 and 3′AG′2 and their associated sequences triggered usage of a third 3′AG′3 that has very weak associated sequences. Interestingly, when intron splicing was directed to the 3′AG′ cryptic splice-sites, intron splicing from the canonical 3′AG splice-site was reduced along with a decrease in cassette exon inclusion. Moreover, multiple SRSF2 binding sites within the intron are responsible for 3′AG′ activation. We conclude that SRSF2 facilitates exon exclusion by activating a cryptic 3′AG′ and inhibiting downstream intron splicing.
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35
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Wachutka L, Caizzi L, Gagneur J, Cramer P. Global donor and acceptor splicing site kinetics in human cells. eLife 2019; 8:45056. [PMID: 31025937 PMCID: PMC6548502 DOI: 10.7554/elife.45056] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 04/25/2019] [Indexed: 11/13/2022] Open
Abstract
RNA splicing is an essential part of eukaryotic gene expression. Although the mechanism of splicing has been extensively studied in vitro, in vivo kinetics for the two-step splicing reaction remain poorly understood. Here, we combine transient transcriptome sequencing (TT-seq) and mathematical modeling to quantify RNA metabolic rates at donor and acceptor splice sites across the human genome. Splicing occurs in the range of minutes and is limited by the speed of RNA polymerase elongation. Splicing kinetics strongly depends on the position and nature of nucleotides flanking splice sites, and on structural interactions between unspliced RNA and small nuclear RNAs in spliceosomal intermediates. Finally, we introduce the 'yield' of splicing as the efficiency of converting unspliced to spliced RNA and show that it is highest for mRNAs and independent of splicing kinetics. These results lead to quantitative models describing how splicing rates and yield are encoded in the human genome.
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Affiliation(s)
- Leonhard Wachutka
- Department of Informatics, Technical University of Munich, Garching, Germany
| | - Livia Caizzi
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Julien Gagneur
- Department of Informatics, Technical University of Munich, Garching, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
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36
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Brant AC, Majerciak V, Moreira MAM, Zheng ZM. HPV18 Utilizes Two Alternative Branch Sites for E6*I Splicing to Produce E7 Protein. Virol Sin 2019; 34:211-221. [PMID: 30945125 PMCID: PMC6513837 DOI: 10.1007/s12250-019-00098-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/21/2019] [Indexed: 12/26/2022] Open
Abstract
Human papillomavirus 18 (HPV18) E6 and E7 oncogenes are transcribed as a single bicistronic E6E7 pre-mRNA. The E6 ORF region in the bicistronic E6E7 pre-mRNA contains an intron. Splicing of this intron disrupts the E6 ORF integrity and produces a spliced E6*I RNA for efficient E7 translation. Here we report that the E6 intron has two overlapped branch point sequences (BPS) upstream of its 3′ splice site, with an identical heptamer AACUAAC, for E6*I splicing. One heptamer has a branch site adenosine (underlined) at nt 384 and the other at nt 388. E6*I splicing efficiency correlates to the expression level of E6 and E7 proteins and depends on the selection of which branch site. In general, E6*I splicing prefers the 3′ss-proximal branch site at nt 388 over the distal branch site at nt 384. Inactivation of the nt 388 branch site was found to activate a cryptic acceptor site at nt 636 for aberrant RNA splicing. Together, these data suggest that HPV18 modulates its production ratio of E6 and E7 proteins by alternative selection of the two mapped branch sites for the E6*I splicing, which could be beneficial in its productive or oncogenic infection according to the host cell environment.
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Affiliation(s)
- Ayslan Castro Brant
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702, USA.,Genetics Post-Graduation Program, Rio de Janeiro Federal University, Rio de Janeiro, Brazil.,Genetics Program, Nacional Cancer Institute, INCA, Rio de Janeiro, 20231-050, Brazil
| | - Vladimir Majerciak
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702, USA
| | | | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702, USA.
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37
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Loerch S, Leach JR, Horner SW, Maji D, Jenkins JL, Pulvino MJ, Kielkopf CL. The pre-mRNA splicing and transcription factor Tat-SF1 is a functional partner of the spliceosome SF3b1 subunit via a U2AF homology motif interface. J Biol Chem 2018; 294:2892-2902. [PMID: 30567737 DOI: 10.1074/jbc.ra118.006764] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/10/2018] [Indexed: 01/09/2023] Open
Abstract
The transcription elongation and pre-mRNA splicing factor Tat-SF1 associates with the U2 small nuclear ribonucleoprotein (snRNP) of the spliceosome. However, the direct binding partner and underlying interactions mediating the Tat-SF1-U2 snRNP association remain unknown. Here, we identified SF3b1 as a Tat-SF1-interacting subunit of the U2 snRNP. Our 1.1 Å resolution crystal structure revealed that Tat-SF1 contains a U2AF homology motif (UHM) protein-protein interaction module. We demonstrated that Tat-SF1 preferentially and directly binds the SF3b1 subunit compared with other U2AF ligand motif (ULM)-containing splicing factors, and further established that SF3b1 association depends on the integrity of the Tat-SF1 UHM. We next compared the Tat-SF1-binding affinities for each of the five known SF3b1 ULMs and then determined the structures of representative high- and low-affinity SF3b1 ULM complexes with the Tat-SF1 UHM at 1.9 Å and 2.1 Å resolutions, respectively. These structures revealed a canonical UHM-ULM interface, comprising a Tat-SF1 binding pocket for a ULM tryptophan (SF3b1 Trp338) and electrostatic interactions with a basic ULM tail. Importantly, we found that SF3b1 regulates Tat-SF1 levels and that these two factors influence expression of overlapping representative transcripts, consistent with a functional partnership of Tat-SF1 and SF3b1. Altogether, these results define a new molecular interface of the Tat-SF1-U2 snRNP complex for gene regulation.
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Affiliation(s)
- Sarah Loerch
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Justin R Leach
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Steven W Horner
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Debanjana Maji
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Jermaine L Jenkins
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Mary J Pulvino
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Clara L Kielkopf
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
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38
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Zhou C, Gao X, Hu S, Gan W, Xu J, Ma YC, Ma L. RBM-5 modulates U2AF large subunit-dependent alternative splicing in C. elegans. RNA Biol 2018; 15:1295-1308. [PMID: 30295127 PMCID: PMC6284560 DOI: 10.1080/15476286.2018.1526540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/23/2018] [Accepted: 09/11/2018] [Indexed: 01/06/2023] Open
Abstract
A key step in pre-mRNA splicing is the recognition of 3' splicing sites by the U2AF large and small subunits, a process regulated by numerous trans-acting splicing factors. How these trans-acting factors interact with U2AF in vivo is unclear. From a screen for suppressors of the temperature-sensitive (ts) lethality of the C. elegans U2AF large subunit gene uaf-1(n4588) mutants, we identified mutations in the RNA binding motif gene rbm-5, a homolog of the tumor suppressor gene RBM5. rbm-5 mutations can suppress uaf-1(n4588) ts-lethality by loss of function and neuronal expression of rbm-5 was sufficient to rescue the suppression. Transcriptome analyses indicate that uaf-1(n4588) affected the expression of numerous genes and rbm-5 mutations can partially reverse the abnormal gene expression to levels similar to that of wild type. Though rbm-5 mutations did not obviously affect alternative splicing per se, they can suppress or enhance, in a gene-specific manner, the altered splicing of genes in uaf-1(n4588) mutants. Specifically, the recognition of a weak 3' splice site was more susceptible to the effect of rbm-5. Our findings provide novel in vivo evidence that RBM-5 can modulate UAF-1-dependent RNA splicing and suggest that RBM5 might interact with U2AF large subunit to affect tumor formation.
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Affiliation(s)
- Chuanman Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaoyang Gao
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Surong Hu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Wenjing Gan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Jing Xu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yongchao C. Ma
- Departments of Pediatrics, Neurology and Physiology, Northwestern University Feinberg School of Medicine, Anne & Robert H. Lurie Children’s Hospital of Chicago, Chicago, Illinois, USA
| | - Long Ma
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
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39
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Wang S, Xia P, Cacalano NA, Xu H, Li D. Complete androgen insensitivity syndrome caused by c.1769-1G > C mutation and activation of a cryptic splice acceptor site in the androgen receptor gene. Steroids 2018; 137:64-69. [PMID: 29859233 DOI: 10.1016/j.steroids.2018.05.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 05/28/2018] [Indexed: 12/21/2022]
Abstract
Androgen insensitivity syndrome (AIS) is the most common cause of 46,XY disorders of sex development (46,XY DSD). This syndrome is an X-linked recessive genetic disease characterized by resistance to the actions of androgens in an individual with a male karyotype and it is caused by mutations in the androgen receptor (AR) gene. We evaluated two siblings with primary amenorrhea, normal secondary sex characteristics, absence of uterus and ovaries, intra-abdominal testis, and elevated testosterone levels. Sequence analysis of the AR gene revealed a splice acceptor site mutation in intron 2 (c.1769-1G > C). The analysis of mRNA showed that this mutation resulted in the activation of a cryptic splice acceptor site located in intron 2 and in the synthesis of an aberrant mRNA transcript with 69 nucleotides insertion between exon 2 and exon 3, leading to an insertion of 23 amino acids in the AR protein instead of generating a premature termination codon. The additional 23 amino acids insertion affects AR intracellular trafficking by impairing its translocation from the cytoplasm to the nucleus after hormone stimulation. The c.1769-1G > C mutation provides new insights into the molecular mechanism involved in splicing defects and expands the spectrum of mutations associated with the androgen insensitivity syndrome.
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Affiliation(s)
- Song Wang
- Department of Urology, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China
| | - Peng Xia
- Department of Spinal Surgery, Orthopedics Hospital, The Second Hospital of Jilin University, Changchun, Jilin 130041, PR China
| | - Nicholas A Cacalano
- Department of Radiation Oncology, University of California Los Angeles School of Medicine, Los Angeles, CA 90095, USA
| | - Haikun Xu
- Department of Radiology, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, PR China.
| | - Dejun Li
- Center for Prenatal Diagnosis, The First Hospital of Jilin University, Changchun, Jilin 130021, PR China.
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40
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James AB, Calixto CP, Tzioutziou NA, Guo W, Zhang R, Simpson CG, Jiang W, Nimmo GA, Brown JW, Nimmo HG. How does temperature affect splicing events? Isoform switching of splicing factors regulates splicing of LATE ELONGATED HYPOCOTYL (LHY). PLANT, CELL & ENVIRONMENT 2018; 41. [PMID: 29532482 PMCID: PMC6033173 DOI: 10.1111/pce.13193] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
One of the ways in which plants can respond to temperature is via alternative splicing (AS). Previous work showed that temperature changes affected the splicing of several circadian clock gene transcripts. Here, we investigated the role of RNA-binding splicing factors (SFs) in temperature-sensitive AS of the clock gene LATE ELONGATED HYPOCOTYL (LHY). We characterized, in wild type plants, temperature-associated isoform switching and expression patterns for SF transcripts from a high-resolution temperature and time series RNA-seq experiment. In addition, we employed quantitative RT-PCR of SF mutant plants to explore the role of the SFs in cooling-associated AS of LHY. We show that the splicing and expression of several SFs responds sufficiently, rapidly, and sensitively to temperature changes to contribute to the splicing of the 5'UTR of LHY. Moreover, the choice of splice site in LHY was altered in some SF mutants. The splicing of the 5'UTR region of LHY has characteristics of a molecular thermostat, where the ratio of transcript isoforms is sensitive to temperature changes as modest as 2 °C and is scalable over a wide dynamic range of temperature. Our work provides novel insight into SF-mediated coupling of the perception of temperature to post-transcriptional regulation of the clock.
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Affiliation(s)
- Allan B. James
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life SciencesUniversity of GlasgowGlasgowG12 8QQScotlandUK
| | - Cristiane P.G. Calixto
- Plant Sciences Division, College of Life SciencesUniversity of DundeeInvergowrieDundeeDD2 5DAScotlandUK
| | - Nikoleta A. Tzioutziou
- Plant Sciences Division, College of Life SciencesUniversity of DundeeInvergowrieDundeeDD2 5DAScotlandUK
| | - Wenbin Guo
- Informatics and Computational SciencesThe James Hutton InstituteInvergowrieDundeeDD2 5DAScotlandUK
| | - Runxuan Zhang
- Informatics and Computational SciencesThe James Hutton InstituteInvergowrieDundeeDD2 5DAScotlandUK
| | - Craig G. Simpson
- Cell and Molecular SciencesThe James Hutton InstituteInvergowrieDundeeDD2 5DAScotlandUK
| | - Wenying Jiang
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life SciencesUniversity of GlasgowGlasgowG12 8QQScotlandUK
| | - Gillian A. Nimmo
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life SciencesUniversity of GlasgowGlasgowG12 8QQScotlandUK
| | - John W.S. Brown
- Plant Sciences Division, College of Life SciencesUniversity of DundeeInvergowrieDundeeDD2 5DAScotlandUK
- Cell and Molecular SciencesThe James Hutton InstituteInvergowrieDundeeDD2 5DAScotlandUK
| | - Hugh G. Nimmo
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life SciencesUniversity of GlasgowGlasgowG12 8QQScotlandUK
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41
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Herdt O, Neumann A, Timmermann B, Heyd F. The cancer-associated U2AF35 470A>G (Q157R) mutation creates an in-frame alternative 5' splice site that impacts splicing regulation in Q157R patients. RNA (NEW YORK, N.Y.) 2017; 23:1796-1806. [PMID: 28893951 PMCID: PMC5689001 DOI: 10.1261/rna.061432.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
Recent work has identified cancer-associated U2AF35 missense mutations in two zinc-finger (ZnF) domains, but little is known about Q157R/P substitutions within the second ZnF. Surprisingly, we find that the c.470A>G mutation not only leads to the Q157R substitution, but also creates an alternative 5' splice site (ss) resulting in the deletion of four amino acids (Q157Rdel). Q157P, Q157R, and Q157Rdel control alternative splicing of distinct groups of exons in cell culture and in human patients, suggesting that missplicing of different targets may contribute to cellular aberrations. Our data emphasize the importance to explore missense mutations beyond altered protein sequence.
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Affiliation(s)
- Olga Herdt
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Alexander Neumann
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Bernd Timmermann
- Sequencing Core Facility, Max-Planck-Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Florian Heyd
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
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42
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Yeh CS, Chang SL, Chen JH, Wang HK, Chou YC, Wang CH, Huang SH, Larson A, Pleiss JA, Chang WH, Chang TH. The conserved AU dinucleotide at the 5' end of nascent U1 snRNA is optimized for the interaction with nuclear cap-binding-complex. Nucleic Acids Res 2017; 45:9679-9693. [PMID: 28934473 PMCID: PMC5766165 DOI: 10.1093/nar/gkx608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/05/2017] [Indexed: 11/13/2022] Open
Abstract
Splicing is initiated by a productive interaction between the pre-mRNA and the U1 snRNP, in which a short RNA duplex is established between the 5' splice site of a pre-mRNA and the 5' end of the U1 snRNA. A long-standing puzzle has been why the AU dincucleotide at the 5'-end of the U1 snRNA is highly conserved, despite the absence of an apparent role in the formation of the duplex. To explore this conundrum, we varied this AU dinucleotide into all possible permutations and analyzed the resulting molecular consequences. This led to the unexpected findings that the AU dinucleotide dictates the optimal binding of cap-binding complex (CBC) to the 5' end of the nascent U1 snRNA, which ultimately influences the utilization of U1 snRNP in splicing. Our data also provide a structural interpretation as to why the AU dinucleotide is conserved during evolution.
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Affiliation(s)
- Chung-Shu Yeh
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.,Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Jui-Hui Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Hsuan-Kai Wang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan.,Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan
| | - Yue-Chang Chou
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Shih-Hsin Huang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan.,Chemical Biology and Molecular Biophysics program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
| | - Amy Larson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jeffrey A Pleiss
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Wei-Hau Chang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tien-Hsien Chang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.,Genomics Research Center, Academia Sinica, Taipei, Taiwan
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43
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Mutations of RNA splicing factors in hematological malignancies. Cancer Lett 2017; 409:1-8. [PMID: 28888996 DOI: 10.1016/j.canlet.2017.08.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 01/01/2023]
Abstract
Systematic large-scale cancer genomic studies have produced numerous significant findings. These studies have not only revealed new cancer-promoting genes, but they also have identified cancer-promoting functions of previously known "housekeeping" genes. These studies have identified numerous mutations in genes which play a fundamental role in nuclear precursor mRNA splicing. Somatic mutations and copy number variation in many of the splicing factors which participate in the formation of multiple spliceosomal complexes appear to play a role in many cancers and in particular in myelodysplastic syndromes (MDS). Mutated proteins seem to interfere with the recognition of the authentic splice sites (SS) leading to utilization of suboptimal alternative splicing sites generating aberrantly spliced mRNA isoforms. This short review is focusing on the function of the splice factors involved in the formation of splicing complexes and potential mechanisms which affect usage of the authentic splice site recognition.
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44
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Glasser E, Agrawal AA, Jenkins JL, Kielkopf CL. Cancer-Associated Mutations Mapped on High-Resolution Structures of the U2AF2 RNA Recognition Motifs. Biochemistry 2017; 56:4757-4761. [PMID: 28850223 DOI: 10.1021/acs.biochem.7b00551] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Acquired point mutations of pre-mRNA splicing factors recur among cancers, leukemias, and related neoplasms. Several studies have established that somatic mutations of a U2AF1 subunit, which normally recognizes 3' splice site junctions, recur among myelodysplastic syndromes. The U2AF2 splicing factor recognizes polypyrimidine signals that precede most 3' splice sites as a heterodimer with U2AF1. In contrast with those of the well-studied U2AF1 subunit, descriptions of cancer-relevant U2AF2 mutations and their structural relationships are lacking. Here, we survey databases of cancer-associated mutations and identify recurring missense mutations in the U2AF2 gene. We determine ultra-high-resolution structures of the U2AF2 RNA recognition motifs (RRM1 and RRM2) at 1.1 Å resolution and map the structural locations of the mutated U2AF2 residues. Comparison with prior, lower-resolution structures of the tandem U2AF2 RRMs in the RNA-bound and apo states reveals clusters of cancer-associated mutations at the U2AF2 RRM-RNA or apo-RRM1-RRM2 interfaces. Although the role of U2AF2 mutations in malignant transformation remains uncertain, our results show that cancer-associated mutations correlate with functionally important surfaces of the U2AF2 splicing factor.
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Affiliation(s)
- Eliezra Glasser
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry , Rochester, New York 14642, United States
| | - Anant A Agrawal
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry , Rochester, New York 14642, United States
| | - Jermaine L Jenkins
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry , Rochester, New York 14642, United States
| | - Clara L Kielkopf
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry , Rochester, New York 14642, United States
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45
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Larson JD, Hoskins AA. Dynamics and consequences of spliceosome E complex formation. eLife 2017; 6:27592. [PMID: 28829039 PMCID: PMC5779234 DOI: 10.7554/elife.27592] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 08/21/2017] [Indexed: 12/26/2022] Open
Abstract
The spliceosome must identify the correct splice sites (SS) and branchsite (BS) used during splicing. E complex is the earliest spliceosome precursor in which the 5' SS and BS are defined. Definition occurs by U1 small nuclear ribonucleoprotein (snRNP) binding the 5' SS and recognition of the BS by the E complex protein (ECP) branchpoint bridging protein (BBP). We have used single molecule fluorescence to study Saccharomyces cerevisiae U1 and BBP interactions with RNAs. E complex is dynamic and permits frequent redefinition of the 5' SS and BS. BBP influences U1 binding at the 5' SS by promoting long-lived complex formation. ECPs facilitate U1 association with RNAs with weak 5' SS and prevent U1 accumulation on RNAs containing hyperstabilized 5' SS. The data reveal a mechanism for how U1 binds the 5' SS and suggest that E complex harnesses this mechanism to stimulate recruitment and retention of U1 on introns. Our genes contain coded instructions for making the molecules in our bodies, but this information must be extensively processed before it can be used. The instructions from each gene are first copied into a molecule called a pre-mRNA, before a process known as splicing removes certain sections to form a mature mRNA molecule. Splicing can remove different sections of the pre-mRNA to make different mRNA molecules from the same gene depending on the current needs of the cell. Splicing is controlled by a combination of proteins and other molecules, collectively called the spliceosome. A part of the spliceosome called U1 recognizes the start of pre-mRNA sections that need to be removed, which is referred to as the five-prime splice site (or “5’ SS” for short). The attachment of U1 to such a site allows other molecules to also attach to the pre-mRNA, which eventually assemble a spliceosome. The very first steps in this process involve U1 and a set of other proteins that create what is called the “Early” or “E” complex. Although there are many molecules involved in the E complex, it was not known how they interact with each other and how this affects which splice sites are used for splicing in different cells. Using advanced microscopy, Larson and Hoskins examined individual U1 molecules from yeast cells while the molecules formed E complexes and identified two different ways U1 can bind to five-prime splice sites. One process involved U1 attaching to pre-mRNA for a short time, whilst the other involved a longer association between U1 and pre-mRNA. Sometimes U1 could also transition between the first process and the second. The results showed that other parts of the E complex affected which process was used at different sites by affecting the type or duration of U1’s attachment. All U1 particles use the same components to attach to splice sites in all pre-mRNAs, but the most used splice sites are not always those that are predicted to have the strongest attachments to U1. This work helps to reveal how other proteins involved in splicing influence this effect, altering U1’s ability to attach to pre-mRNAs to suit each new situation. This also allows cells to change gene splicing to fit different situations. Many genes in our bodies rely on splicing and understanding this process in detail could be the key to diagnosing and treating a range of different illnesses.
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Affiliation(s)
- Joshua Donald Larson
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States.,Biophysics Graduate Program, University of Wisconsin-Madison, Madison, United States
| | - Aaron A Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States.,Biophysics Graduate Program, University of Wisconsin-Madison, Madison, United States
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Liu H, Zhang L, Wei Q, Shi Z, Shi X, Du J, Huang C, Zhang Y, Guo Z. Comprehensive Proteomic Analysis of PGC7-Interacting Proteins. J Proteome Res 2017; 16:3113-3123. [PMID: 28712289 DOI: 10.1021/acs.jproteome.6b00883] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Primordial germ cell 7 (PGC7), a maternal factor essential for early development, plays a critical role in the regulation of DNA methylation, transcriptional repression, chromatin condensation, and cell division and the maintenance of cell pluripotentiality. Despite the fundamental roles of PGC7 in these cellular processes, only a few molecular and functional interactions of PGC7 have been reported. Here, a streptavidin-biotin affinity purification technique combined with LC-MS/MS was used to analyze potential proteins that interact with PGC7. In total, 291 potential PGC7-interacting proteins were identified. Through an in-depth bioinformatic analysis of potential interactors, we linked PGC7 to critical cellular processes including translation, RNA processing, cell cycle, and regulation of heterochromatin structure. To better understand the functional interactions of PGC7 with its potential interactors, we constructed a protein-protein interaction network using the STRING database. In addition, we discussed in detail the interactions between PGC7 and some of its newly validated partners. The identification of these potential interactors of PGC7 expands our knowledge on the PGC7 interactome and provides a valuable resource for understanding the diverse functions of this protein.
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Affiliation(s)
- Hongliang Liu
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China
| | - Lei Zhang
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China
| | - Qing Wei
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China
| | - Zhaopeng Shi
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China
| | - Xiaoyan Shi
- Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China.,Medical Experiment Center of Shaanxi University of Chinese Medicine , Xianyang, Shaanxi 712000, China
| | - Juan Du
- Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China.,Medicine School of Yan'an University , Yan'an, Shaanxi 716000, China
| | - Chenyang Huang
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China
| | - Yong Zhang
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China
| | - Zekun Guo
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China.,Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100, China
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Grewal CS, Kent OA, MacMillan AM. Radical probing of spliceosome assembly. Methods 2017; 125:16-24. [PMID: 28669867 DOI: 10.1016/j.ymeth.2017.06.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 06/21/2017] [Accepted: 06/24/2017] [Indexed: 10/19/2022] Open
Abstract
Here we describe the synthesis and use of a directed hydroxyl radical probe, tethered to a pre-mRNA substrate, to map the structure of this substrate during the spliceosome assembly process. These studies indicate an early organization and proximation of conserved pre-mRNA sequences during spliceosome assembly. This methodology may be adapted to the synthesis of a wide variety of modified RNAs for use as probes of RNA structure and RNA-protein interaction.
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Affiliation(s)
- Charnpal S Grewal
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Oliver A Kent
- Princess Margaret Cancer Centre, 101 College St., University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Andrew M MacMillan
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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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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Deep intronic mutations and human disease. Hum Genet 2017; 136:1093-1111. [DOI: 10.1007/s00439-017-1809-4] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/05/2017] [Indexed: 12/22/2022]
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Muthuramalingam M, Wang Y, Li Y, Mahalingam R. Interacting protein partners of Arabidopsis RNA-binding protein AtRBP45b. PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:327-334. [PMID: 28039930 DOI: 10.1111/plb.12540] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 12/29/2016] [Indexed: 05/19/2023]
Abstract
RNA binding proteins, important players in post-transcriptional gene regulation, usually exist in ribonuclear complexes. However, even in model systems like Arabidopsis characterisation of RBP associated proteins is limited. In this study, we investigated the interacting proteins of the Arabidopsis AtRBP45b, which is involved in stress signalling. In vivo localisation of AtRBP45b was conducted using 35S-GFP. FLAG-tagged AtRBP45b under control of the 35S promoter in the Atrbp45b-1 mutant background was used to pull down AtRBP45b interacting proteins. Yeast two-hybrid analysis, fluorescence energy resonance transfer assays were used to confirm the veracity of the AtRBP45b interacting proteins. In planta GFP-tagging indicated AtRBP45b is localised to the nucleus and the cytosol. AtRBP45b protein has a N-terminal proline-rich region and a C-terminal glutamine-rich domain that are usually involved in protein-protein interactions. Co-immunoprecipitation followed by mass spectrometry-based protein sequencing led to identification of 30 proteins that interacted with AtRBP45b. Using information from interactome databases (BIOGRID, INTACT and STRING), pull-down assays and localisation data, 12 putative interacting proteins were selected for yeast two-hybrid analysis. Cap-binding protein (CBP20, At5g44200) and polyA-binding protein (PAB8, At1g49760) were shown to interact with AtRBP45b. Based on its interacting partners we speculate that AtRBP45b may play an important role in RNA metabolism, especially in aspects related to mRNA stability and translation initiation during stress conditions in plants.
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Affiliation(s)
- M Muthuramalingam
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Y Wang
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- Department of Plant Biology, Ecology and Evolution, Oklahoma State University, Stillwater, OK, USA
| | - Y Li
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- College of Life Sciences, Henan Normal University, Xinxiang, Henan, China
| | - R Mahalingam
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- USDA-ARS, Cereal Crops Research Unit, Madison, WI, USA
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