1
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Fronk AD, Manzanares MA, Zheng P, Geier A, Anderson K, Stanton S, Zumrut H, Gera S, Munch R, Frederick V, Dhingra P, Arun G, Akerman M. Development and validation of AI/ML derived splice-switching oligonucleotides. Mol Syst Biol 2024; 20:676-701. [PMID: 38664594 PMCID: PMC11148135 DOI: 10.1038/s44320-024-00034-9] [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: 09/15/2023] [Revised: 04/03/2024] [Accepted: 04/09/2024] [Indexed: 06/05/2024] Open
Abstract
Splice-switching oligonucleotides (SSOs) are antisense compounds that act directly on pre-mRNA to modulate alternative splicing (AS). This study demonstrates the value that artificial intelligence/machine learning (AI/ML) provides for the identification of functional, verifiable, and therapeutic SSOs. We trained XGboost tree models using splicing factor (SF) pre-mRNA binding profiles and spliceosome assembly information to identify modulatory SSO binding sites on pre-mRNA. Using Shapley and out-of-bag analyses we also predicted the identity of specific SFs whose binding to pre-mRNA is blocked by SSOs. This step adds considerable transparency to AI/ML-driven drug discovery and informs biological insights useful in further validation steps. We applied this approach to previously established functional SSOs to retrospectively identify the SFs likely to regulate those events. We then took a prospective validation approach using a novel target in triple negative breast cancer (TNBC), NEDD4L exon 13 (NEDD4Le13). Targeting NEDD4Le13 with an AI/ML-designed SSO decreased the proliferative and migratory behavior of TNBC cells via downregulation of the TGFβ pathway. Overall, this study illustrates the ability of AI/ML to extract actionable insights from RNA-seq data.
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Affiliation(s)
| | | | - Paulina Zheng
- Envisagenics, Inc., Long Island City, NY, 11101, USA
| | - Adam Geier
- Envisagenics, Inc., Long Island City, NY, 11101, USA
| | | | | | - Hasan Zumrut
- Envisagenics, Inc., Long Island City, NY, 11101, USA
| | - Sakshi Gera
- Envisagenics, Inc., Long Island City, NY, 11101, USA
| | - Robin Munch
- Envisagenics, Inc., Long Island City, NY, 11101, USA
| | | | | | - Gayatri Arun
- Envisagenics, Inc., Long Island City, NY, 11101, USA
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2
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Chaqour B, Duong TT, Yue J, Liu T, Camacho D, Dine KE, Esteve-Rudd J, Ellis S, Bennett J, Shindler KS, Ross AG. AAV2 vector optimization for retinal ganglion cell-targeted delivery of therapeutic genes. Gene Ther 2024; 31:175-186. [PMID: 38200264 DOI: 10.1038/s41434-023-00436-8] [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: 09/29/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024]
Abstract
Recombinant adeno-associated virus (AAV)-2 has significant potential as a delivery vehicle of therapeutic genes to retinal ganglion cells (RGCs), which are key interventional targets in optic neuropathies. Here we show that when injected intravitreally, AAV2 engineered with a reporter gene driven by cytomegalovirus (CMV) enhancer and chicken β-actin (CBA) promoters, displays ubiquitous and high RGC expression, similar to its synthetic derivative AAV8BP2. A novel AAV2 vector combining the promoter of the human RGC-selective γ-synuclein (hSNCG) gene and woodchuck hepatitis post-transcriptional regulatory element (WPRE) inserted upstream and downstream of a reporter gene, respectively, induces widespread transduction and strong transgene expression in RGCs. High transduction efficiency and selectivity to RGCs is further achieved by incorporating in the vector backbone a leading CMV enhancer and an SV40 intron at the 5' and 3' ends, respectively, of the reporter gene. As a delivery vehicle of hSIRT1, a 2.2-kb therapeutic gene with anti-apoptotic, anti-inflammatory and anti-oxidative stress properties, this recombinant vector displayed improved transduction efficiency, a strong, widespread and selective RGC expression of hSIRT1, and increased RGC survival following optic nerve crush. Thus, AAV2 vector carrying hSNCG promoter with additional regulatory sequences may offer strong potential for enhanced effects of candidate gene therapies targeting RGCs.
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Affiliation(s)
- Brahim Chaqour
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Thu T Duong
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
- GlaxoSmithKline, Collegeville, PA, 19426, USA
| | - Jipeng Yue
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Tehui Liu
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
- Spark Therapeutics, Philadelphia, PA, 19104, USA
| | - David Camacho
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Kimberly E Dine
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | | | - Scott Ellis
- Gyroscope Therapeutics Limited, a Novartis Company, London, N7 9AS, UK
| | - Jean Bennett
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Kenneth S Shindler
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Ahmara G Ross
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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3
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Tse V, Chacaltana G, Gutierrez M, Forino N, Jimenez A, Tao H, Do P, Oh C, Chary P, Quesada I, Hamrick A, Lee S, Stone M, Sanford J. An intronic RNA element modulates Factor VIII exon-16 splicing. Nucleic Acids Res 2024; 52:300-315. [PMID: 37962303 PMCID: PMC10783525 DOI: 10.1093/nar/gkad1034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Pathogenic variants in the human Factor VIII (F8) gene cause Hemophilia A (HA). Here, we investigated the impact of 97 HA-causing single-nucleotide variants on the splicing of 11 exons from F8. For the majority of F8 exons, splicing was insensitive to the presence of HA-causing variants. However, splicing of several exons, including exon-16, was impacted by variants predicted to alter exonic splicing regulatory sequences. Using exon-16 as a model, we investigated the structure-function relationship of HA-causing variants on splicing. Intriguingly, RNA chemical probing analyses revealed a three-way junction structure at the 3'-end of intron-15 (TWJ-3-15) capable of sequestering the polypyrimidine tract. We discovered antisense oligonucleotides (ASOs) targeting TWJ-3-15 partially rescue splicing-deficient exon-16 variants by increasing accessibility of the polypyrimidine tract. The apical stem loop region of TWJ-3-15 also contains two hnRNPA1-dependent intronic splicing silencers (ISSs). ASOs blocking these ISSs also partially rescued splicing. When used in combination, ASOs targeting both the ISSs and the region sequestering the polypyrimidine tract, fully rescue pre-mRNA splicing of multiple HA-linked variants of exon-16. Together, our data reveal a putative RNA structure that sensitizes F8 exon-16 to aberrant splicing.
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Affiliation(s)
- Victor Tse
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
- Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Guillermo Chacaltana
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
- Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Martin Gutierrez
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
- Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Nicholas M Forino
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
- Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Arcelia G Jimenez
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Hanzhang Tao
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Phong H Do
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Catherine Oh
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Priyanka Chary
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Isabel Quesada
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Antonia Hamrick
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Sophie Lee
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
- Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Jeremy R Sanford
- Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
- Center for Molecular Biology of RNA, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
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4
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Jia ZC, Das D, Zhang Y, Fernie AR, Liu YG, Chen M, Zhang J. Plant serine/arginine-rich proteins: versatile players in RNA processing. PLANTA 2023; 257:109. [PMID: 37145304 DOI: 10.1007/s00425-023-04132-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 04/05/2023] [Indexed: 05/06/2023]
Abstract
MAIN CONCLUSION Serine/arginine-rich (SR) proteins participate in RNA processing by interacting with precursor mRNAs or other splicing factors to maintain plant growth and stress responses. Alternative splicing is an important mechanism involved in mRNA processing and regulation of gene expression at the posttranscriptional level, which is the main reason for the diversity of genes and proteins. The process of alternative splicing requires the participation of many specific splicing factors. The SR protein family is a splicing factor in eukaryotes. The vast majority of SR proteins' existence is an essential survival factor. Through its RS domain and other unique domains, SR proteins can interact with specific sequences of precursor mRNA or other splicing factors and cooperate to complete the correct selection of splicing sites or promote the formation of spliceosomes. They play essential roles in the composition and alternative splicing of precursor mRNAs, providing pivotal functions to maintain growth and stress responses in animals and plants. Although SR proteins have been identified in plants for three decades, their evolutionary trajectory, molecular function, and regulatory network remain largely unknown compared to their animal counterparts. This article reviews the current understanding of this gene family in eukaryotes and proposes potential key research priorities for future functional studies.
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Affiliation(s)
- Zi-Chang Jia
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang, 550025, China
| | - Debatosh Das
- College of Agriculture, Food and Natural Resources (CAFNR), Division of Plant Sciences and Technology, 52 Agricultural Building, University of Missouri, Columbia, MO, 65201, USA
- Department of Biology, Hong Kong Baptist University, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Youjun Zhang
- Center of Plant System Biology and Biotechnology, 4000, Plovdiv, Bulgaria
- Max-Planck-Institut Für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Alisdair R Fernie
- Center of Plant System Biology and Biotechnology, 4000, Plovdiv, Bulgaria
- Max-Planck-Institut Für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Ying-Gao Liu
- State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Taian, Shandong, China
| | - Moxian Chen
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Guiyang, 550025, China.
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
| | - Jianhua Zhang
- Department of Biology, Hong Kong Baptist University, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong.
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Tse V, Chacaltana G, Gutierrez M, Forino NM, Jimenez AG, Tao H, Do PH, Oh C, Chary P, Quesada I, Hamrick A, Lee S, Stone MD, Sanford JR. Rescue of blood coagulation Factor VIII exon-16 mis-splicing by antisense oligonucleotides. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535160. [PMID: 37034721 PMCID: PMC10081312 DOI: 10.1101/2023.03.31.535160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The human Factor VIII ( F8 ) protein is essential for the blood coagulation cascade and specific F8 mutations cause the rare bleeding disorder Hemophilia A (HA). Here, we investigated the impact of HA-causing single-nucleotide mutations on F8 pre-mRNA splicing. We found that 14/97 (∼14.4%) coding sequence mutations tested in our study induced exon skipping. Splicing patterns of 4/11 (∼36.4%) F8 exons tested were especially sensitive to the presence of common disease-causing mutations. RNA-chemical probing analyses revealed a three-way junction structure at the 3' end of intron 15 (TWJ-3-15). TWJ-3-15 sequesters the polypyrimidine tract, a key determinant of 3' splice site strength. Using exon-16 of the F8 gene as a model, we designed specific antisense oligonucleotides (ASOs) that target TWJ-3-15 and identified three that promote the splicing of F8 exon-16. Interaction of TWJ-3-15 with ASOs increases accessibility of the polypyrimidine tract and inhibits the binding of hnRNPA1-dependent splicing silencing factors. Moreover, ASOs targeting TWJ-3-15 rescue diverse splicing-sensitive HA-causing mutations, most of which are distal to the 3' splice site being impacted. The TWJ-3-15 structure and its effect on mRNA splicing provide a model for HA etiology in patients harboring specific F8 mutations and provide a framework for precision RNA-based HA therapies.
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6
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Sybilska E, Daszkowska-Golec A. Alternative splicing in ABA signaling during seed germination. FRONTIERS IN PLANT SCIENCE 2023; 14:1144990. [PMID: 37008485 PMCID: PMC10060653 DOI: 10.3389/fpls.2023.1144990] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 03/02/2023] [Indexed: 06/19/2023]
Abstract
Seed germination is an essential step in a plant's life cycle. It is controlled by complex physiological, biochemical, and molecular mechanisms and external factors. Alternative splicing (AS) is a co-transcriptional mechanism that regulates gene expression and produces multiple mRNA variants from a single gene to modulate transcriptome diversity. However, little is known about the effect of AS on the function of generated protein isoforms. The latest reports indicate that alternative splicing (AS), the relevant mechanism controlling gene expression, plays a significant role in abscisic acid (ABA) signaling. In this review, we present the current state of the art about the identified AS regulators and the ABA-related changes in AS during seed germination. We show how they are connected with the ABA signaling and the seed germination process. We also discuss changes in the structure of the generated AS isoforms and their impact on the functionality of the generated proteins. Also, we point out that the advances in sequencing technology allow for a better explanation of the role of AS in gene regulation by more accurate detection of AS events and identification of full-length splicing isoforms.
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7
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Feng J, Zhou J, Lin Y, Huang W. hnRNP A1 in RNA metabolism regulation and as a potential therapeutic target. Front Pharmacol 2022; 13:986409. [PMID: 36339596 PMCID: PMC9634572 DOI: 10.3389/fphar.2022.986409] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/10/2022] [Indexed: 11/22/2022] Open
Abstract
Abnormal RNA metabolism, regulated by various RNA binding proteins, can have functional consequences for multiple diseases. Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is an important RNA binding protein, that regulates various RNA metabolic processes, including transcription, alternative splicing of pre-mRNA, translation, miRNA processing and mRNA stability. As a potent splicing factor, hnRNP A1 can regulate multiple splicing events, including itself, collaborating with other cooperative or antagonistical splicing factors by binding to splicing sites and regulatory elements in exons or introns. hnRNP A1 can modulate gene transcription by directly interacting with promoters or indirectly impacting Pol II activities. Moreover, by interacting with the internal ribosome entry site (IRES) or 3′-UTR of mRNAs, hnRNP A1 can affect mRNA translation. hnRNP A1 can alter the stability of mRNAs by binding to specific locations of 3′-UTR, miRNAs biogenesis and Nonsense-mediated mRNA decay (NMD) pathway. In this review, we conclude the selective sites where hnRNP A1 binds to RNA and DNA, and the co-regulatory factors that interact with hnRNP A1. Given the dysregulation of hnRNP A1 in diverse diseases, especially in cancers and neurodegeneration diseases, targeting hnRNP A1 for therapeutic treatment is extremely promising. Therefore, this review also provides the small-molecule drugs, biomedicines and novel strategies targeting hnRNP A1 for therapeutic purposes.
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8
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Sarkar A, Panati K, Narala VR. Code inside the codon: The role of synonymous mutations in regulating splicing machinery and its impact on disease. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2022; 790:108444. [PMID: 36307006 DOI: 10.1016/j.mrrev.2022.108444] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 10/10/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
In eukaryotes, precise pre-mRNA processing, including alternative splicing, is essential to carry out the intricate protein translation process. Both point mutations (that alter the translated protein sequence) and synonymous mutations (that do not alter the translated protein sequence) are capable of affecting the splicing process. Synonymous mutations are known to affect gene expression via altering mRNA stability, mRNA secondary structure, splicing processes, and translational kinetics. In higher eukaryotes, precise splicing is regulated by three weakly conserved cis-elements, 5' and 3' splice sites and the branch site. Many other cis-acting elements (exonic/intronic splicing enhancers and silencers) and trans-acting splicing factors (serine and arginine-rich proteins and heterogeneous nuclear ribonucleoproteins) have also been found to enhance or suppress the splicing process. The appearance of synonymous mutations in cis-acting elements can alter the splicing process by changing the binding pattern of splicing factors to exonic splicing enhancers or silencer motifs. This results in exon skipping, intron retention, and various other forms of alternative splicing, eventually leading to the emergence of a wide range of diseases. The focus of this review is to elucidate the role of synonymous mutations and their impact on abnormal splicing mechanisms. Further, this study highlights the function of synonymous mutation in mediating abnormal splicing in cancer and development of X-linked, and autosomal inherited diseases.
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Affiliation(s)
- Avik Sarkar
- Department of Zoology, Vidyasagar University, Midnapore, West Bengal 721102, India
| | - Kalpana Panati
- Department of Biotechnology, Government College for Men, Kadapa 516004, India
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9
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High Concentration or Combined Treatment of Antisense Oligonucleotides for Spinal Muscular Atrophy Perturbed SMN2 Splicing in Patient Fibroblasts. Genes (Basel) 2022; 13:genes13040685. [PMID: 35456491 PMCID: PMC9027857 DOI: 10.3390/genes13040685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 02/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is caused by survival motor neuron 1 SMN1 deletion. The survival motor neuron 2 (SMN2) encodes the same protein as SMN1 does, but it has a splicing defect of exon 7. Some antisense oligonucleotides (ASOs) have been proven to correct this defect. One of these, nusinersen, is effective in SMA-affected infants, but not as much so in advanced-stage patients. Furthermore, the current regimen may exhibit a ceiling effect. To overcome these problems, high-dose ASOs or combined ASOs have been explored. Here, using SMA fibroblasts, we examined the effects of high-concentration ASOs and of combining two ASOs. Three ASOs were examined: one targeting intronic splicing suppressor site N1 (ISS-N1) in intron 7, and two others targeting the 3′ splice site and 5′ region of exon 8. In our experiments on all ASO types, a low or intermediate concentration (50 or 100 nM) showed better splicing efficiency than a high concentration (200 nM). In addition, a high concentration of each ASO created a cryptic exon in exon 6. When a mixture of two different ASOs (100 nM each) was added to the cells, the cryptic exon was included in the mRNA. In conclusion, ASOs at a high concentration or used in combination may show less splicing correction and cryptic exon creation.
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10
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Jobbins AM, Campagne S, Weinmeister R, Lucas CM, Gosliga AR, Clery A, Chen L, Eperon LP, Hodson MJ, Hudson AJ, Allain FHT, Eperon IC. Exon-independent recruitment of SRSF1 is mediated by U1 snRNP stem-loop 3. EMBO J 2022; 41:e107640. [PMID: 34779515 PMCID: PMC8724738 DOI: 10.15252/embj.2021107640] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022] Open
Abstract
SRSF1 protein and U1 snRNPs are closely connected splicing factors. They both stimulate exon inclusion, SRSF1 by binding to exonic splicing enhancer sequences (ESEs) and U1 snRNPs by binding to the downstream 5' splice site (SS), and both factors affect 5' SS selection. The binding of U1 snRNPs initiates spliceosome assembly, but SR proteins such as SRSF1 can in some cases substitute for it. The mechanistic basis of this relationship is poorly understood. We show here by single-molecule methods that a single molecule of SRSF1 can be recruited by a U1 snRNP. This reaction is independent of exon sequences and separate from the U1-independent process of binding to an ESE. Structural analysis and cross-linking data show that SRSF1 contacts U1 snRNA stem-loop 3, which is required for splicing. We suggest that the recruitment of SRSF1 to a U1 snRNP at a 5'SS is the basis for exon definition by U1 snRNP and might be one of the principal functions of U1 snRNPs in the core reactions of splicing in mammals.
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Affiliation(s)
- Andrew M Jobbins
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
MRC London Institute of Medical SciencesLondonUK
- Present address:
Institute of Clinical SciencesImperial College LondonLondonUK
| | - Sébastien Campagne
- Institute of BiochemistryETH ZürichSwitzerland
- Present address:
Inserm U1212CNRS UMR5320ARNA LaboratoryBordeaux CedexFrance
| | - Robert Weinmeister
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | - Christian M Lucas
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Alison R Gosliga
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
- Present address:
Institut für Industrielle GenetikAbt.(eilung) SystembiologieUniversität StuttgartStuttgartGermany
| | | | - Li Chen
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Lucy P Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Mark J Hodson
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
| | - Andrew J Hudson
- Leicester Institute of Structural & Chemical Biology and Department of ChemistryUniversity of LeicesterLeicesterUK
| | | | - Ian C Eperon
- Leicester Institute of Structural & Chemical Biology and Department of Molecular & Cell BiologyUniversity of LeicesterLeicesterUK
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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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Huang R, Zheng Z, Liu S, Yan P, Song D, Yin H, Hu P, Zhu X, Chang Z, Liu Y, Zhuang J, Meng T, Huang Z, Zhang J. Identification of prognostic and bone metastasis-related alternative splicing signatures in mesothelioma. Cancer Med 2021; 10:4478-4492. [PMID: 34041868 PMCID: PMC8267146 DOI: 10.1002/cam4.3977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 01/18/2023] Open
Abstract
Mesothelioma (MESO) is an infrequent tumor derived from mesothelial cells of pleura, peritoneum, pericardium, and tunica vaginalis testis. Despite advancement in technologies and better understanding of tumor progression mechanism, the prognosis of MESO remains poor. The role of alternative splicing events (ASEs) in the oncogenesis, tumor metastasis and drug resistance has been widely discussed in multiple cancers. But the prognosis and potential therapeutic value of ASEs in MESO were not clearly studied by now. We constructed a prognostic model using RNA sequencing data and matched ASE data of MESO patients obtained from the TCGA and TCGASpliceSeq database. A total of 3,993 ASEs were identified associated with overall survival using Cox regression analysis. Eight of them were finally figured out to institute the model by lasso regression analysis. The risk score of the model can predict the prognosis independently. Among the identified 390 splicing factors (SF), HSPA1A and DDX3Y was significantly associated with 43 OS-SEs. Among these OS-SEs, SNX5-58744-AT (p = 0.048) and SNX5-58745-AT (p = 0.048) were significantly associated with bone metastasis. Co-expression analysis of signal pathways and SNX5-58744-AT, SNX5-58745-AT was also depicted using GSVA. Finally, we proposed that splicing factor (SF) HSPA1A could regulate SNX5-58744-AT (R = -0.414) and SNX5-58745-AT (R = 0.414) through the pathway "Class I MHC mediated antigen processing and presentation" (R = 0.400). In this way, tumorigenesis and bone metastasis of MESO were controlled.
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Affiliation(s)
- Runzhi Huang
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China.,Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Tongji University School of Medicine, Shanghai, China
| | - Zixuan Zheng
- Tongji University School of Medicine, Shanghai, China
| | - Sijia Liu
- Tongji University School of Medicine, Shanghai, China
| | - Penghui Yan
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Dianwen Song
- Department of Orthopedics, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Huabin Yin
- Department of Orthopedics, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Peng Hu
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaolong Zhu
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhengyan Chang
- Department of Pathology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yihan Liu
- Tongji University School of Medicine, Shanghai, China
| | - Juanwei Zhuang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Tong Meng
- Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Department of Orthopedics, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Zongqiang Huang
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jie Zhang
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China.,Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University School of Medicine, Shanghai, China.,Tongji University School of Medicine, Shanghai, China
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13
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Daniels NJ, Hershberger CE, Gu X, Schueger C, DiPasquale WM, Brick J, Saunthararajah Y, Maciejewski JP, Padgett RA. Functional analyses of human LUC7-like proteins involved in splicing regulation and myeloid neoplasms. Cell Rep 2021; 35:108989. [PMID: 33852859 PMCID: PMC8078730 DOI: 10.1016/j.celrep.2021.108989] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/12/2021] [Accepted: 03/23/2021] [Indexed: 02/06/2023] Open
Abstract
Vertebrates have evolved three paralogs, termed LUC7L, LUC7L2, and LUC7L3, of the essential yeast U1 small nuclear RNA (snRNA)-associated splicing factor Luc7p. We investigated the mechanistic and regulatory functions of these putative splicing factors, of which one (LUC7L2) is mutated or deleted in myeloid neoplasms. Protein interaction data show that all three proteins bind similar core but distinct regulatory splicing factors, probably mediated through their divergent arginine-serine-rich domains, which are not present in Luc7p. Knockdown of each factor reveals mostly unique sets of significantly dysregulated alternative splicing events dependent on their binding locations, which are largely non-overlapping. Notably, knockdown of LUC7L2 alone significantly upregulates the expression of multiple spliceosomal factors and downregulates glycolysis genes, possibly contributing to disease pathogenesis. RNA binding studies reveal that LUC7L2 and LUC7L3 crosslink to weak 5' splice sites and to the 5' end of U1 snRNA, establishing an evolutionarily conserved role in 5' splice site selection.
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Affiliation(s)
- Noah J Daniels
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, USA; Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Courtney E Hershberger
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, USA; Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Xiaorong Gu
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Caroline Schueger
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, USA; Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - William M DiPasquale
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jonathan Brick
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Yogen Saunthararajah
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jaroslaw P Maciejewski
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Richard A Padgett
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, USA; Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
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14
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Kováčová T, Souček P, Hujová P, Freiberger T, Grodecká L. Splicing Enhancers at Intron-Exon Borders Participate in Acceptor Splice Sites Recognition. Int J Mol Sci 2020; 21:ijms21186553. [PMID: 32911621 PMCID: PMC7554774 DOI: 10.3390/ijms21186553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/05/2020] [Accepted: 09/06/2020] [Indexed: 02/07/2023] Open
Abstract
Acceptor splice site recognition (3′ splice site: 3′ss) is a fundamental step in precursor messenger RNA (pre-mRNA) splicing. Generally, the U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor (U2AF) heterodimer recognizes the 3′ss, of which U2AF35 has a dual function: (i) It binds to the intron–exon border of some 3′ss and (ii) mediates enhancer-binding splicing activators’ interactions with the spliceosome. Alternative mechanisms for 3′ss recognition have been suggested, yet they are still not thoroughly understood. Here, we analyzed 3′ss recognition where the intron–exon border is bound by a ubiquitous splicing regulator SRSF1. Using the minigene analysis of two model exons and their mutants, BRCA2 exon 12 and VARS2 exon 17, we showed that the exon inclusion correlated much better with the predicted SRSF1 affinity than 3′ss quality, which were assessed using the Catalog of Inferred Sequence Binding Preferences of RNA binding proteins (CISBP-RNA) database and maximum entropy algorithm (MaxEnt) predictor and the U2AF35 consensus matrix, respectively. RNA affinity purification proved SRSF1 binding to the model 3′ss. On the other hand, knockdown experiments revealed that U2AF35 also plays a role in these exons’ inclusion. Most probably, both factors stochastically bind the 3′ss, supporting exon recognition, more apparently in VARS2 exon 17. Identifying splicing activators as 3′ss recognition factors is crucial for both a basic understanding of splicing regulation and human genetic diagnostics when assessing variants’ effects on splicing.
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Affiliation(s)
- Tatiana Kováčová
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic; (T.K.); (P.S.); (P.H.); (T.F.)
- Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
| | - Přemysl Souček
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic; (T.K.); (P.S.); (P.H.); (T.F.)
- Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
| | - Pavla Hujová
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic; (T.K.); (P.S.); (P.H.); (T.F.)
- Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
| | - Tomáš Freiberger
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic; (T.K.); (P.S.); (P.H.); (T.F.)
- Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
| | - Lucie Grodecká
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, 656 91 Brno, Czech Republic; (T.K.); (P.S.); (P.H.); (T.F.)
- Correspondence:
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15
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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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16
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Suess B, Kemmerer K, Weigand JE. Splicing and Alternative Splicing Impact on Gene Design. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Beatrix Suess
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Katrin Kemmerer
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Julia E. Weigand
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
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17
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Xu DH, Wang XY, Jia YL, Wang TY, Tian ZW, Feng X, Zhang YN. SV40 intron, a potent strong intron element that effectively increases transgene expression in transfected Chinese hamster ovary cells. J Cell Mol Med 2018; 22:2231-2239. [PMID: 29441681 PMCID: PMC5867124 DOI: 10.1111/jcmm.13504] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/15/2017] [Indexed: 12/20/2022] Open
Abstract
Chinese hamster ovary (CHO) cells have become the most widely utilized mammalian cell line for the production of recombinant proteins. However, the product yield and transgene instability need to be further increased and solved. In this study, we investigated the effect of five different introns on transgene expression in CHO cells. hCMV intron A, adenovirus tripartite leader sequence intron, SV40 intron, Chinese hamster EF-1alpha gene intron 1 and intervening sequence intron were cloned downstream of the eGFP expression cassette in a eukaryotic vector, which was then transfected into CHO cells. qRT-PCR and flow cytometry were used to explore eGFP expression levels. And gene copy number was also detected by qPCR, respectively. Furthermore, the erythropoietin (EPO) protein was used to test the selected more strong intron. The results showed that SV40 intron exhibited the highest transgene expression level among the five compared intron elements under transient and stable transfections. In addition, the SV40 intron element can increase the ratio of positive colonies and decrease the coefficient of variation in transgene expression level. Moreover, the transgene expression level was not related to the gene copy number in stable transfected CHO cells. Also, the SV40 intron induced higher level of EPO expression than IVS intron in transfected CHO cell. In conclusion, SV40 intron is a potent strong intron element that increases transgene expression, which can readily be used to more efficient transgenic protein production in CHO cells.
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Affiliation(s)
- Dan-Hua Xu
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao-Yin Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Yan-Long Jia
- Pharmacy collage, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Zheng-Wei Tian
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xin Feng
- Grade 2014, The Third Clinical Medical College of Xinxiang Medical University, Xinxiang, Henan, China
| | - Yin-Na Zhang
- Grade 2014, The Third Clinical Medical College of Xinxiang Medical University, Xinxiang, Henan, China
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18
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Chen L, Weinmeister R, Kralovicova J, Eperon LP, Vorechovsky I, Hudson AJ, Eperon IC. Stoichiometries of U2AF35, U2AF65 and U2 snRNP reveal new early spliceosome assembly pathways. Nucleic Acids Res 2017; 45:2051-2067. [PMID: 27683217 PMCID: PMC5389562 DOI: 10.1093/nar/gkw860] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/16/2016] [Indexed: 12/24/2022] Open
Abstract
The selection of 3΄ splice sites (3΄ss) is an essential early step in mammalian RNA splicing reactions, but the processes involved are unknown. We have used single molecule methods to test whether the major components implicated in selection, the proteins U2AF35 and U2AF65 and the U2 snRNP, are able to recognize alternative candidate sites or are restricted to one pre-specified site. In the presence of adenosine triphosphate (ATP), all three components bind in a 1:1 stoichiometry with a 3΄ss. Pre-mRNA molecules with two alternative 3΄ss can be bound concurrently by two molecules of U2AF or two U2 snRNPs, so none of the components are restricted. However, concurrent occupancy inhibits splicing. Stoichiometric binding requires conditions consistent with coalescence of the 5΄ and 3΄ sites in a complex (I, initial), but if this cannot form the components show unrestricted and stochastic association. In the absence of ATP, when complex E forms, U2 snRNP association is unrestricted. However, if protein dephosphorylation is prevented, an I-like complex forms with stoichiometric association of U2 snRNPs and the U2 snRNA is base-paired to the pre-mRNA. Complex I differs from complex A in that the formation of complex A is associated with the loss of U2AF65 and 35.
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Affiliation(s)
- Li Chen
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Robert Weinmeister
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Lucy P Eperon
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Andrew J Hudson
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Chemistry, Leicester LE1 7RH, UK
| | - Ian C Eperon
- University of Leicester, Leicester Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, Leicester LE1 9HN, UK
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19
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Yi J, Shen HF, Qiu JS, Huang MF, Zhang WJ, Ding JC, Zhu XY, Zhou Y, Fu XD, Liu W. JMJD6 and U2AF65 co-regulate alternative splicing in both JMJD6 enzymatic activity dependent and independent manner. Nucleic Acids Res 2017; 45:3503-3518. [PMID: 27899633 PMCID: PMC5389685 DOI: 10.1093/nar/gkw1144] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 11/02/2016] [Indexed: 12/11/2022] Open
Abstract
JMJD6, a jumonji C (Jmj C) domain-containing protein demethylase and hydroxylase, has been implicated in an array of biological processes. It has been shown that JMJD6 interacts with and hydroxylates multiple serine/arginine-rich (SR) proteins and SR related proteins, including U2AF65, all of which are known to function in alternative splicing regulation. However, whether JMJD6 is widely involved in alternative splicing and the molecular mechanism underlying JMJD6-regulated alternative splicing have remained incompletely understood. Here, by using RASL-Seq, we investigated the functional impact of RNA-dependent interaction between JMJD6 and U2AF65, revealing that JMJD6 and U2AF65 co-regulated a large number of alternative splicing events. We further demonstrated the JMJD6 function in alternative splicing in jmjd6 knockout mice. Mechanistically, we showed that the enzymatic activity of JMJD6 was required for a subset of JMJD6-regulated splicing, and JMJD6-mediated lysine hydroxylation of U2AF65 could account for, at least partially, their co-regulated alternative splicing events, suggesting both JMJD6 enzymatic activity-dependent and independent control of alternative splicing. These findings reveal an intimate link between JMJD6 and U2AF65 in alternative splicing regulation, which has important implications in development and disease processes.
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Affiliation(s)
- Jia Yi
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Hai-Feng Shen
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Jin-Song Qiu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0651, USA
| | - Ming-Feng Huang
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Wen-Juan Zhang
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Jian-Cheng Ding
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
| | - Xiao-Yan Zhu
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0648, USA
| | - Yu Zhou
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0651, USA
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0651, USA
| | - Wen Liu
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China
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20
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Kong XZ, Hu SS, Sun Z, Zuo LH, Kang J, Zhu ZF, Tian X, Zhang XJ. Regulation of aerobic glycolysis by long non-coding RNAs in cancer. Biochem Biophys Res Commun 2016; 479:28-32. [DOI: 10.1016/j.bbrc.2016.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 09/01/2016] [Indexed: 02/07/2023]
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21
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Kralovicova J, Vorechovsky I. Alternative splicing of U2AF1 reveals a shared repression mechanism for duplicated exons. Nucleic Acids Res 2016; 45:417-434. [PMID: 27566151 PMCID: PMC5224494 DOI: 10.1093/nar/gkw733] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 12/30/2022] Open
Abstract
The auxiliary factor of U2 small nuclear ribonucleoprotein (U2AF) facilitates branch point (BP) recognition and formation of lariat introns. The gene for the 35-kD subunit of U2AF gives rise to two protein isoforms (termed U2AF35a and U2AF35b) that are encoded by alternatively spliced exons 3 and Ab, respectively. The splicing recognition sequences of exon 3 are less favorable than exon Ab, yet U2AF35a expression is higher than U2AF35b across tissues. We show that U2AF35b repression is facilitated by weak, closely spaced BPs next to a long polypyrimidine tract of exon Ab. Each BP lacked canonical uridines at position -2 relative to the BP adenines, with efficient U2 base-pairing interactions predicted only for shifted registers reminiscent of programmed ribosomal frameshifting. The BP cluster was compensated by interactions involving unpaired cytosines in an upstream, EvoFold-predicted stem loop (termed ESL) that binds FUBP1/2. Exon Ab inclusion correlated with predicted free energies of mutant ESLs, suggesting that the ESL operates as a conserved rheostat between long inverted repeats upstream of each exon. The isoform-specific U2AF35 expression was U2AF65-dependent, required interactions between the U2AF-homology motif (UHM) and the α6 helix of U2AF35, and was fine-tuned by exon Ab/3 variants. Finally, we identify tandem homologous exons regulated by U2AF and show that their preferential responses to U2AF65-related proteins and SRSF3 are associated with unpaired pre-mRNA segments upstream of U2AF-repressed 3′ss. These results provide new insights into tissue-specific subfunctionalization of duplicated exons in vertebrate evolution and expand the repertoire of exon repression mechanisms that control alternative splicing.
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Affiliation(s)
- Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
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22
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Meyer F. Viral interactions with components of the splicing machinery. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 142:241-68. [PMID: 27571697 DOI: 10.1016/bs.pmbts.2016.05.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Eukaryotic genes are often interrupted by stretches of sequence with no protein coding potential or obvious function. After transcription, these interrupting sequences must be removed to give rise to the mature messenger RNA. This fundamental process is called RNA splicing and is achieved by complicated machinery made of protein and RNA that assembles around the RNA to be edited. Viruses also use RNA splicing to maximize their coding potential and economize on genetic space, and use clever strategies to manipulate the splicing machinery to their advantage. This article gives an overview of the splicing process and provides examples of viral strategies that make use of various components of the splicing system to promote their replicative cycle. Representative virus families have been selected to illustrate the interaction with various regulatory proteins and ribonucleoproteins. The unifying theme is fine regulation through protein-protein and protein-RNA interactions with the spliceosome components and associated factors to promote or prevent spliceosome assembly on given splice sites, in addition to a strong influence from cis-regulatory sequences on viral transcripts. Because there is an intimate coupling of splicing with the processes that direct mRNA biogenesis, a description of how these viruses couple the regulation of splicing with the retention or stability of mRNAs is also included. It seems that a unique balance of suppression and activation of splicing and nuclear export works optimally for each family of viruses.
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Affiliation(s)
- F Meyer
- Department of Biochemistry & Molecular Biology, Entomology & Plant Pathology, Mississippi State University, Starkville, MS, USA.
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Zhang Z, Zhou N, Huang J, Ho TT, Zhu Z, Qiu Z, Zhou X, Bai C, Wu F, Xu M, Mo YY. Regulation of androgen receptor splice variant AR3 by PCGEM1. Oncotarget 2016; 7:15481-91. [PMID: 26848868 PMCID: PMC4941255 DOI: 10.18632/oncotarget.7139] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/23/2016] [Indexed: 11/25/2022] Open
Abstract
The androgen receptor (AR) is required for prostate development and is also a major driver of prostate cancer pathogenesis. Thus androgen deprivation therapy (ADT) is the mainstay of treatment for advanced prostate cancer. However, castration resistance due to expression of constitutively active AR splice variants is a significant challenge to prostate cancer therapy; little is known why effectiveness of ADT can only last for a relatively short time. In the present study, we show that PCGEM1 interacts with splicing factors heterogeneous nuclear ribonucleoprotein (hnRNP) A1 and U2AF65, as determined by RNA precipitation and Western blot, suggesting a role for PCGEM1 in alternative splicing. In support of this possibility, PCGEM1 is correlated with AR3, a predominant and clinically important form of AR splice variants in prostate cancer. Moreover, androgen deprivation (AD) induces PCGEM1 and causes its accumulation in nuclear speckles. Finally, we show that the AD-induced PCGEM1 regulates the competition between hnRNP A1 and U2AF65 for AR pre-mRNA. AD promotes PCGEM1 to interact with both hnRNP A1 and U2AF65 with different consequences. While the interaction of PCGEM1 with hnRNP A1 suppresses AR3 by exon skipping, its interaction with U2AF65 promotes AR3 by exonization. Together, we demonstrate an AD-mediated AR3 expression involving PCGEM1 and splicing factors.
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Affiliation(s)
- Ziqiang Zhang
- Department of Pharmacology/Toxicology and Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
- Department of Pulmonary Medicine, Tongji Hospital, Tongji University, Shanghai, China
| | - Nanjiang Zhou
- Department of Biochemistry and Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Jianguo Huang
- Department of Biochemistry and Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Tsui-Ting Ho
- Department of Pharmacology/Toxicology and Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Zhuxian Zhu
- Department of Nephrology, Tongji Hospital, Tongji University, Shanghai, China
| | - Zhongmin Qiu
- Department of Pulmonary Medicine, Tongji Hospital, Tongji University, Shanghai, China
| | - Xinchun Zhou
- Department of Pathology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Chunxue Bai
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, PR China
| | | | - Min Xu
- Department of Gastroenterology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Yin-Yuan Mo
- Department of Pharmacology/Toxicology and Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
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Matos L, Gonçalves V, Pinto E, Laranjeira F, Prata MJ, Jordan P, Desviat LR, Pérez B, Alves S. Functional analysis of splicing mutations in the IDS gene and the use of antisense oligonucleotides to exploit an alternative therapy for MPS II. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2712-21. [PMID: 26407519 DOI: 10.1016/j.bbadis.2015.09.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 09/16/2015] [Accepted: 09/21/2015] [Indexed: 12/12/2022]
Abstract
Mucopolysaccharidosis II is a lysosomal storage disorder caused by mutations in the IDS gene, including exonic alterations associated with aberrant splicing. In the present work, cell-based splicing assays were performed to study the effects of two splicing mutations in exon 3 of IDS, i.e., c.241C>T and c.257C>T, whose presence activates a cryptic splice site in exon 3 and one in exon 8, i.e., c.1122C>T that despite being a synonymous mutation is responsible for the creation of a new splice site in exon 8 leading to a transcript shorter than usual. Mutant minigene analysis and overexpression assays revealed that SRSF2 and hnRNP E1 might be involved in the use and repression of the constitutive 3' splice site of exon 3 respectively. For the c.1122C>T the use of antisense therapy to correct the splicing defect was explored, but transfection of patient fibroblasts with antisense morpholino oligonucleotides (n=3) and a locked nucleic acid failed to abolish the abnormal transcript; indeed, it resulted in the appearance of yet another aberrant splicing product. Interestingly, the oligonucleotides transfection in control fibroblasts led to the appearance of the aberrant transcript observed in patients' cells after treatment, which shows that the oligonucleotides are masking an important cis-acting element for 5' splice site regulation of exon 8. These results highlight the importance of functional studies for understanding the pathogenic consequences of mis-splicing and highlight the difficulty in developing antisense therapies involving gene regions under complex splicing regulation.
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Affiliation(s)
- Liliana Matos
- Research and Development Unit, Department of Human Genetics, INSA, Porto, Portugal; Department of Biology, Faculty of Sciences, University of Porto, Porto, Portugal.
| | - Vânia Gonçalves
- Research and Development Unit, Department of Human Genetics, INSA, Lisbon, Portugal.
| | - Eugénia Pinto
- Biochemical Genetics Unit, Center for Medical Genetics Jacinto Magalhães, Porto Hospital Center, Porto, Portugal.
| | - Francisco Laranjeira
- Biochemical Genetics Unit, Center for Medical Genetics Jacinto Magalhães, Porto Hospital Center, Porto, Portugal.
| | - Maria João Prata
- Department of Biology, Faculty of Sciences, University of Porto, Porto, Portugal; i3S - Instituto de Investigação e Inovação em Saúde/IPATIMUP - Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal.
| | - Peter Jordan
- Research and Development Unit, Department of Human Genetics, INSA, Lisbon, Portugal.
| | - Lourdes R Desviat
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; IDIPaz, Madrid, Spain.
| | - Belén Pérez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, UAM-CSIC, Universidad Autónoma de Madrid, Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; IDIPaz, Madrid, Spain.
| | - Sandra Alves
- Research and Development Unit, Department of Human Genetics, INSA, Porto, Portugal.
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Sakuma M, Iida K, Hagiwara M. Deciphering targeting rules of splicing modulator compounds: case of TG003. BMC Mol Biol 2015; 16:16. [PMID: 26400733 PMCID: PMC4580995 DOI: 10.1186/s12867-015-0044-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/11/2015] [Indexed: 11/10/2022] Open
Abstract
Background Recent advances in the development of small chemical compounds that can modulate RNA splicing brought excitement to the field of splicing-targeting therapy. Splicing-targeting therapy tries to ameliorate the disease by altering the exon combination of transcripts to reduce the undesired effect of genetic mutations. However, the knowledge and tools to understand factors contributing to splicing modulator compound sensitivity have been lacking. Our goal was to establish a method to characterize sequence features found in compound sensitive exons. Results Here we developed a comparative transcriptomic approach to explore features that make an exon sensitive to a chemical compound. In this study, we chose TG003, a potential drug for Duchenne muscular dystrophy, and performed RNA-sequencing on samples from human and mouse skeletal muscle cells, with and without TG003 treatments. We compared TG003 responsiveness between homologous exon pairs and identified 21 pairs in which human exons were skip-enhanced but not mouse exons. We compared the sequence features; splice site scores, number of splicing factor binding sites, and properties of branch sequence and polypyrimidine tracts, and found that polypyrimidine tracts were stronger (longer stretches and richer content of consecutive polypyrimidine) in the mouse TG003 insensitive exons. We also compared the features between TG003 skip-enhanced and insensitive exons within the species, and discovered that human TG003 skip-enhanced exons were shorter and had less splicing factor binding sites than the group of human TG003 insensitive exons. Mouse insensitive exons homologous to human TG003 skip-enhanced exons shared these properties. Our results suggested that these features are prerequisites for TG003 skip-enhanced exons and weak polypyrimidine tracts are defining features, which were supported by a decision tree analysis on all cassette exons in human. Conclusions In this study we established a comparative transcriptomic approach, which shed lights on how small chemical compounds modulate RNA splicing. The results described here was the first attempt to decipher the targeting rules of a splicing modulator compound. We expect that this approach would contribute to the precise understanding of the mechanism of TG003-induced splicing modulation, expand target diseases of splicing modulators in general, as well as the development of new splicing modulators. Electronic supplementary material The online version of this article (doi:10.1186/s12867-015-0044-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maki Sakuma
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Kei Iida
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Masatoshi Hagiwara
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan. .,Medical Research Support Center, Kyoto University Graduate School of Medicine, Konoecho Yoshida Sakyo-ku, Kyoto, 606-8501, Japan.
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26
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Conserved proline-directed phosphorylation regulates SR protein conformation and splicing function. Biochem J 2015; 466:311-22. [PMID: 25529026 DOI: 10.1042/bj20141373] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The alternative splicing of human genes is dependent on SR proteins, a family of essential splicing factors whose name derives from a signature C-terminal domain rich in arginine-serine dipeptide repeats (RS domains). Although the SRPKs (SR-specific protein kinases) phosphorylate these repeats, RS domains also contain prolines with flanking serines that are phosphorylated by a second family of protein kinases known as the CLKs (Cdc2-like kinases). The role of specific serine-proline phosphorylation within the RS domain has been difficult to assign since CLKs also phosphorylate arginine-serine dipeptides and, thus, display overlapping residue specificities with the SRPKs. In the present study, we address the effects of discrete serine-proline phosphorylation on the conformation and cellular function of the SR protein SRSF1 (SR protein splicing factor 1). Using chemical tagging and dephosphorylation experiments, we show that modification of serine-proline dipeptides broadly amplifies the conformational ensemble of SRSF1. The induction of these new structural forms triggers SRSF1 mobilization in the nucleus and alters its binding mechanism to an exonic splicing enhancer in precursor mRNA. These physical events correlate with changes in the alternative splicing of over 100 human genes based on a global splicing assay. Overall, these studies draw a direct causal relationship between a specific type of chemical modification in an SR protein and the regulation of alternative gene splicing programmes.
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Kralovicova J, Knut M, Cross NCP, Vorechovsky I. Identification of U2AF(35)-dependent exons by RNA-Seq reveals a link between 3' splice-site organization and activity of U2AF-related proteins. Nucleic Acids Res 2015; 43:3747-63. [PMID: 25779042 PMCID: PMC4402522 DOI: 10.1093/nar/gkv194] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 02/24/2015] [Indexed: 01/05/2023] Open
Abstract
The auxiliary factor of U2 small nuclear RNA (U2AF) is a heterodimer consisting of 65- and 35-kD proteins that bind the polypyrimidine tract (PPT) and AG dinucleotides at the 3′ splice site (3′ss). The gene encoding U2AF35 (U2AF1) is alternatively spliced, giving rise to two isoforms U2AF35a and U2AF35b. Here, we knocked down U2AF35 and each isoform and characterized transcriptomes of HEK293 cells with varying U2AF35/U2AF65 and U2AF35a/b ratios. Depletion of both isoforms preferentially modified alternative RNA processing events without widespread failure to recognize 3′ss or constitutive exons. Over a third of differentially used exons were terminal, resulting largely from the use of known alternative polyadenylation (APA) sites. Intronic APA sites activated in depleted cultures were mostly proximal whereas tandem 3′UTR APA was biased toward distal sites. Exons upregulated in depleted cells were preceded by longer AG exclusion zones and PPTs than downregulated or control exons and were largely activated by PUF60 and repressed by CAPERα. The U2AF(35) repression and activation was associated with a significant interchange in the average probabilities to form single-stranded RNA in the optimal PPT and branch site locations and sequences further upstream. Although most differentially used exons were responsive to both U2AF subunits and their inclusion correlated with U2AF levels, a small number of transcripts exhibited distinct responses to U2AF35a and U2AF35b, supporting the existence of isoform-specific interactions. These results provide new insights into function of U2AF and U2AF35 in alternative RNA processing.
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Affiliation(s)
- Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Marcin Knut
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Nicholas C P Cross
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury SP2 8BJ, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
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A targeted oligonucleotide enhancer of SMN2 exon 7 splicing forms competing quadruplex and protein complexes in functional conditions. Cell Rep 2014; 9:193-205. [PMID: 25263560 PMCID: PMC4536295 DOI: 10.1016/j.celrep.2014.08.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/17/2014] [Accepted: 08/21/2014] [Indexed: 01/20/2023] Open
Abstract
The use of oligonucleotides to activate the splicing of selected exons is limited by a poor understanding of the mechanisms affected. A targeted bifunctional oligonucleotide enhancer of splicing (TOES) anneals to SMN2 exon 7 and carries an exonic splicing enhancer (ESE) sequence. We show that it stimulates splicing specifically of intron 6 in the presence of repressing sequences in intron 7. Complementarity to the 5' end of exon 7 increases U2AF65 binding, but the ESE sequence is required for efficient recruitment of U2 snRNP. The ESE forms at least three coexisting discrete states: a quadruplex, a complex containing only hnRNP F/H, and a complex enriched in the activator SRSF1. Neither hnRNP H nor quadruplex formation contributes to ESE activity. The results suggest that splicing limited by weak signals can be rescued by rapid exchange of TOES oligonucleotides in various complexes and raise the possibility that SR proteins associate transiently with ESEs.
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29
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Howard JM, Sanford JR. The RNAissance family: SR proteins as multifaceted regulators of gene expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:93-110. [PMID: 25155147 DOI: 10.1002/wrna.1260] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/09/2014] [Accepted: 07/14/2014] [Indexed: 12/29/2022]
Abstract
Serine and arginine-rich (SR) proteins play multiple roles in the eukaryotic gene expression pathway. Initially described as constitutive and alternative splicing factors, now it is clear that SR proteins are key determinants of exon identity and function as molecular adaptors, linking the pre-messenger RNA (pre-mRNA) to the splicing machinery. In addition, now SR proteins are implicated in many aspects of mRNA and noncoding RNA (ncRNA) processing well beyond splicing. These unexpected roles, including RNA transcription, export, translation, and decay, may prove to be the rule rather than the exception. To simply define, this family of RNA-binding proteins as splicing factors belies the broader roles of SR proteins in post-transcriptional gene expression.
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Affiliation(s)
- Jonathan M Howard
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, USA
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30
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Regulation of gene expression programmes by serine–arginine rich splicing factors. Semin Cell Dev Biol 2014; 32:11-21. [DOI: 10.1016/j.semcdb.2014.03.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/11/2014] [Indexed: 12/21/2022]
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31
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Heim A, Grimm C, Müller U, Häußler S, Mackeen MM, Merl J, Hauck SM, Kessler BM, Schofield CJ, Wolf A, Böttger A. Jumonji domain containing protein 6 (Jmjd6) modulates splicing and specifically interacts with arginine-serine-rich (RS) domains of SR- and SR-like proteins. Nucleic Acids Res 2014; 42:7833-50. [PMID: 24914048 PMCID: PMC4081092 DOI: 10.1093/nar/gku488] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The Fe(II) and 2-oxoglutarate dependent oxygenase Jmjd6 has been shown to hydroxylate lysine residues in the essential splice factor U2 auxiliary factor 65 kDa subunit (U2AF65) and to act as a modulator of alternative splicing. We describe further evidence for the role of Jmjd6 in the regulation of pre-mRNA processing including interactions of Jmjd6 with multiple arginine–serine-rich (RS)-domains of SR- and SR-related proteins including U2AF65, Luc7-like protein 3 (Luc7L3), SRSF11 and Acinus S′, but not with the bona fide RS-domain of SRSF1. The identified Jmjd6 target proteins are involved in different mRNA processing steps and play roles in exon dependent alternative splicing and exon definition. Moreover, we show that Jmjd6 modifies splicing of a constitutive splice reporter, binds RNA derived from the reporter plasmid and punctually co-localises with nascent RNA. We propose that Jmjd6 exerts its splice modulatory function by interacting with specific SR-related proteins during splicing in a RNA dependent manner.
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Affiliation(s)
- Astrid Heim
- Department of Biology II, Ludwig Maximilians University, Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Christina Grimm
- Department of Biology II, Ludwig Maximilians University, Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Udo Müller
- Department of Biology II, Ludwig Maximilians University, Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Simon Häußler
- Department of Biology II, Ludwig Maximilians University, Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Mukram M Mackeen
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK Research Unit Protein Science, Helmholtz Zentrum München-German Research Center for Environmental Health, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Juliane Merl
- Henry Wellcome Building for Molecular Physiology, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Stefanie M Hauck
- Henry Wellcome Building for Molecular Physiology, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Benedikt M Kessler
- School of Chemical Science, Faculty of Science and Technology, and Institute of Systems Biology (INBIOSIS) Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia
| | - Christopher J Schofield
- Chemistry Research Laboratory and Oxford Centre for Integrative Systems Biology, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Alexander Wolf
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München-German Research Center for Environmental Health, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Angelika Böttger
- Department of Biology II, Ludwig Maximilians University, Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany
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Wu Y, Jin Y, Pan W, Ye C, Sun X, Sun Y, Hu B, Zhou J. Comparative proteomics analysis of host cells infected with Brucella abortus A19. Electrophoresis 2014; 35:1130-43. [PMID: 24519676 DOI: 10.1002/elps.201300378] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 01/23/2014] [Accepted: 01/24/2014] [Indexed: 01/18/2023]
Abstract
We carried out a proteomic analysis of THP-1-derived macrophages with and without Brucella abortus A19 (B. abortus A19) infection in order to study the cellular responses to B. abortus A19. The proteins were analyzed at different time points after infection with 2DE followed by MALDI-TOF/TOF identification. Comparative analysis of multiple 2DE gels revealed that the majority of changes in protein abundance appeared between 48 and 96 h after infection. MS identified 44 altered proteins, including 20 proteins increased in abundance and 24 proteins decreased in abundance, which were found to be involved in cytoskeleton, signal transduction, energy metabolism, host macromolecular biosynthesis, and stress response. Moreover, 22 genes corresponding to the altered proteins were quantified by real-time RT-PCR to examine the transcriptional profiles between infected and uninfected THP-1-derived macrophages. Finally, we mapped the altered pathways and networks using ingenuity pathway analysis, which suggested that the altered protein species were heavily favored germ cell-Sertoli cell junction signaling as the primary pathway. Furthermore, mechanisms of viral exit from host cell and macrophage stimulating protein-recepteur d'origine nantais signaling appeared to be major pathways modulated in infected cells. This study effectively provides useful dynamic protein-related information concerning B. abortus infection in macrophages.
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Affiliation(s)
- Yongping Wu
- College of Animal Sciences and Technology, Zhejiang A&F University, Hangzhou, P.R. China; Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang University, Hangzhou, P.R. China
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Grodecká L, Lockerová P, Ravčuková B, Buratti E, Baralle FE, Dušek L, Freiberger T. Exon first nucleotide mutations in splicing: evaluation of in silico prediction tools. PLoS One 2014; 9:e89570. [PMID: 24586880 PMCID: PMC3931810 DOI: 10.1371/journal.pone.0089570] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/21/2014] [Indexed: 12/20/2022] Open
Abstract
Mutations in the first nucleotide of exons (E+1) mostly affect pre-mRNA splicing when found in AG-dependent 3′ splice sites, whereas AG-independent splice sites are more resistant. The AG-dependency, however, may be difficult to assess just from primary sequence data as it depends on the quality of the polypyrimidine tract. For this reason, in silico prediction tools are commonly used to score 3′ splice sites. In this study, we have assessed the ability of sequence features and in silico prediction tools to discriminate between the splicing-affecting and non-affecting E+1 variants. For this purpose, we newly tested 16 substitutions in vitro and derived other variants from literature. Surprisingly, we found that in the presence of the substituting nucleotide, the quality of the polypyrimidine tract alone was not conclusive about its splicing fate. Rather, it was the identity of the substituting nucleotide that markedly influenced it. Among the computational tools tested, the best performance was achieved using the Maximum Entropy Model and Position-Specific Scoring Matrix. As a result of this study, we have now established preliminary discriminative cut-off values showing sensitivity up to 95% and specificity up to 90%. This is expected to improve our ability to detect splicing-affecting variants in a clinical genetic setting.
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Affiliation(s)
- Lucie Grodecká
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Pavla Lockerová
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
| | - Barbora Ravčuková
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Ladislav Dušek
- Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Tomáš Freiberger
- Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Institute of Clinical Immunology and Allergology, St. Anne’s University Hospital and Masaryk University, Brno, Czech Republic
- * E-mail:
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Roberts JM, Ennajdaoui H, Edmondson C, Wirth B, Sanford J, Chen B. Splicing factor TRA2B is required for neural progenitor survival. J Comp Neurol 2014; 522:372-92. [PMID: 23818142 PMCID: PMC3855887 DOI: 10.1002/cne.23405] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/20/2013] [Accepted: 06/21/2013] [Indexed: 01/08/2023]
Abstract
Alternative splicing of pre-mRNAs can rapidly regulate the expression of large groups of proteins. The RNA binding protein TRA2B (SFRS10) plays well-established roles in developmentally regulated alternative splicing during Drosophila sexual differentiation. TRA2B is also essential for mammalian embryogenesis and is implicated in numerous human diseases. Precise regulation of alternative splicing is critical to the development and function of the central nervous system; however, the requirements for specific splicing factors in neurogenesis are poorly understood. This study focuses on the role of TRA2B in mammalian brain development. We show that, during murine cortical neurogenesis, TRA2B is expressed in both neural progenitors and cortical projection neurons. Using cortex-specific Tra2b mutant mice, we show that TRA2B depletion results in apoptosis of the neural progenitor cells as well as disorganization of the cortical plate. Thus, TRA2B is essential for proper development of the cerebral cortex.
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Affiliation(s)
- Jacqueline M Roberts
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Hanane Ennajdaoui
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Carina Edmondson
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Brunhilde Wirth
- Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne 50931, Germany
| | - Jeremy Sanford
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Bin Chen
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
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35
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Sterne-Weiler T, Sanford JR. Exon identity crisis: disease-causing mutations that disrupt the splicing code. Genome Biol 2014; 15:201. [PMID: 24456648 PMCID: PMC4053859 DOI: 10.1186/gb4150] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cis-acting RNA elements control the accurate expression of human multi-exon protein coding genes. Single nucleotide variants altering the fidelity of this regulatory code and, consequently, pre-mRNA splicing are expected to contribute to the etiology of numerous human diseases.
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36
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Chen J, Weiss WA. Alternative splicing in cancer: implications for biology and therapy. Oncogene 2014; 34:1-14. [PMID: 24441040 DOI: 10.1038/onc.2013.570] [Citation(s) in RCA: 194] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/26/2013] [Accepted: 11/26/2013] [Indexed: 12/11/2022]
Abstract
Alternative splicing has critical roles in normal development and can promote growth and survival in cancer. Aberrant splicing, the production of noncanonical and cancer-specific mRNA transcripts, can lead to loss-of-function in tumor suppressors or activation of oncogenes and cancer pathways. Emerging data suggest that aberrant splicing products and loss of canonically spliced variants correlate with stage and progression in malignancy. Here, we review the splicing landscape of TP53, BARD1 and AR to illuminate roles for alternative splicing in cancer. We also examine the intersection between alternative splicing pathways and novel therapeutic approaches.
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Affiliation(s)
- J Chen
- 1] Biomedical Sciences Graduate Program, University of California, San Francisco, CA, USA [2] Department of Neurology, University of California, San Francisco, CA, USA
| | - W A Weiss
- 1] Department of Neurology, University of California, San Francisco, CA, USA [2] Department of Neurological Surgery and Pediatrics, University of California, San Francisco, CA, USA
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Abstract
Alternative splicing plays a prevalent role in generating functionally diversified proteomes from genomes with a more limited repertoire of protein-coding genes. Alternative splicing is frequently regulated with cell type or developmental specificity and in response to signaling pathways, and its mis-regulation can lead to disease. Co-regulated programs of alternative splicing involve interplay between a host of cis-acting transcript features and trans-acting RNA-binding proteins. Here, we review the current state of understanding of the logic and mechanism of regulated alternative splicing and indicate how this understanding can be exploited to manipulate splicing for therapeutic purposes.
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Affiliation(s)
- Miguel B Coelho
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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38
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Aubol BE, Jamros MA, McGlone ML, Adams JA. Splicing kinase SRPK1 conforms to the landscape of its SR protein substrate. Biochemistry 2013; 52:7595-605. [PMID: 24074032 DOI: 10.1021/bi4010864] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The splicing function of SR proteins is regulated by multisite phosphorylation of their C-terminal RS (arginine-serine rich) domains. SRPK1 has been shown to phosphorylate the prototype SR protein SRSF1 using a directional mechanism in which 11 serines flanked by arginines are sequentially fed from a docking groove in the large lobe of the kinase domain to the active site. Although this process is expected to operate on lengthy arginine-serine repeats (≥8), many SR proteins contain smaller repeats of only 1-4 dipeptides, raising the question of how alternate RS domain configurations are phosphorylated. To address this, we studied a splice variant of Tra2β that contains a C-terminal RS domain with short arginine-serine repeats [Tra2β(ΔN)]. We showed that SRPK1 selectively phosphorylates several serines near the C-terminus of the RS domain. SRPK1 uses a distributive mechanism for Tra2β(ΔN) where the rate-limiting step is the dissociation of the protein substrate rather than nucleotide exchange as in the case of SRSF1. Although a functioning docking groove is required for efficient SRSF1 phosphorylation, this conserved structural element is dispensable for Tra2β(ΔN) phosphorylation. These large shifts in mechanism are likely to account for the slower net turnover rate of Tra2β(ΔN) compared to SRSF1 and may signal fundamental differences in phosphorylation among SR proteins with distinctive arginine-serine profiles. Overall, these data indicate that SRPK1 conforms to changes in RS domain architecture using a flexible kinetic mechanism and selective usage of a conserved docking groove.
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Affiliation(s)
- Brandon E Aubol
- Department of Pharmacology, University of California-San Diego , La Jolla, California 92093-0636, United States
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Lee H, Jung J, Shin J, Song M, Kim S, Lee JH, Lee KA, Shin S, Kim UK, Bok J, Lee KY, Choi J, Park H. Correlation between genotype and phenotype in patients with bi-allelicSLC26A4mutations. Clin Genet 2013; 86:270-5. [DOI: 10.1111/cge.12273] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 11/27/2022]
Affiliation(s)
- H.J. Lee
- Department of Otorhinolaryngology
- BK21 Project for Medical Science
| | - J. Jung
- Department of Pharmacology; Yonsei University College of Medicine; Seoul Republic of Korea
- BK21 Project for Medical Science
| | - J.W. Shin
- Department of Otorhinolaryngology
- Soree Ear Clinics; Seoul Republic of Korea
| | | | - S.H. Kim
- Department of Otorhinolaryngology
| | - J.-H. Lee
- Department of Pharmacology; Yonsei University College of Medicine; Seoul Republic of Korea
| | - K.-A. Lee
- Department of Laboratory Medicine; Yonsei University College of Medicine; Seoul Republic of Korea
| | - S. Shin
- Department of Laboratory Medicine; Yonsei University College of Medicine; Seoul Republic of Korea
| | - U.-K. Kim
- Department of Biology, College of Natural Sciences; Kyungpook National University; Daegu Republic of Korea
| | - J. Bok
- Department of Anatomy; Yonsei University College of Medicine; Seoul Republic of Korea
| | - K.-Y. Lee
- Department of Otorhinolaryngology; Kyungpook National University; Daegu Republic of Korea
| | - J.Y. Choi
- Department of Otorhinolaryngology
- BK21 Project for Medical Science
| | - H.J. Park
- Soree Ear Clinics; Seoul Republic of Korea
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40
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Ghigna C, Riva S, Biamonti G. Alternative splicing of tumor suppressors and oncogenes. Cancer Treat Res 2013; 158:95-117. [PMID: 24222355 DOI: 10.1007/978-3-642-31659-3_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Alternative splicing is a fundamental mechanism to modulate gene expression programs in response to different growth and environmental stimuli. There is now ample evidence that alternative splicing errors, caused by mutations in cis-acting elements and defects and/or imbalances in trans-acting factors, may be causatively associated to cancer progression. Recent work indicates the existence of an intricate network of interactions between alternative splicing events and signal transduction pathways. In this network, splicing factors occupy a central position and appear to function both as targets and effectors of regulatory circuits. Thus, a change in their activity deeply affects alternative splicing profiles and hence the cell behavior. Here, we discuss a number of cases that exemplify the involvement of deregulated alternative splicing in tumor progression.
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Affiliation(s)
- Claudia Ghigna
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, 27100, Italy
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41
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Lewis H, Perrett AJ, Burley GA, Eperon IC. An RNA Splicing Enhancer that Does Not Act by Looping. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201202932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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42
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Lewis H, Perrett AJ, Burley GA, Eperon IC. An RNA splicing enhancer that does not act by looping. Angew Chem Int Ed Engl 2012; 51:9800-3. [PMID: 22936639 DOI: 10.1002/anie.201202932] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/10/2012] [Indexed: 12/16/2022]
Abstract
Out of the loop: Do the proteins bound to an enhancer site on pre-mRNA interact directly with the splice site by diffusion (looping), as is generally accepted, or does the intervening RNA play a role? By inserting a PEG linker between an enhancer sequence and alternative splice sites, the interaction of these two elements can be studied. Intervening RNA was essential for the enhancer activity, which rules out the looping model.
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Affiliation(s)
- Helen Lewis
- Department of Chemistry, University of Leicester, Leicester, UK
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43
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Markus MA, Marques FZ, Morris BJ. Resveratrol, by modulating RNA processing factor levels, can influence the alternative splicing of pre-mRNAs. PLoS One 2011; 6:e28926. [PMID: 22174926 PMCID: PMC3236773 DOI: 10.1371/journal.pone.0028926] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 11/17/2011] [Indexed: 11/18/2022] Open
Abstract
Alternative pre-mRNA splicing defects can contribute to, or result from, various diseases, including cancer. Aberrant mRNAs, splicing factors and other RNA processing factors have therefore become targets for new therapeutic interventions. Here we report that the natural polyphenol resveratrol can modulate alternative splicing in a target-specific manner. We transfected minigenes of several alternatively spliceable primary mRNAs into HEK293 cells in the presence or absence of 1, 5, 20 and 50 µM resveratrol and measured exon levels by semi-quantitative PCR after separation by agarose gel electrophoresis. We found that 20 µg/ml and 50 µg/ml of resveratrol affected exon inclusion of SRp20 and SMN2 pre-mRNAs, but not CD44v5 or tau pre-mRNAs. By Western blotting and immunofluorescence we showed that this effect may be due to the ability of resveratrol to change the protein level but not the localization of several RNA processing factors. The processing factors that increased significantly were ASF/SF2, hnRNPA1 and HuR, but resveratrol did not change the levels of RBM4, PTBP1 and U2AF35. By means of siRNA-mediated knockdown we depleted cells of SIRT1, regarded as a major target of resveratrol, and showed that the effect on splicing was not dependent on SIRT1. Our results suggest that resveratrol might be an attractive small molecule to treat diseases in which aberrant splicing has been implicated, and justify more extensive research on the effects of resveratrol on the splicing machinery.
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Affiliation(s)
- M. Andrea Markus
- Basic and Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Francine Z. Marques
- Basic and Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Brian J. Morris
- Basic and Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, Australia
- * E-mail:
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44
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Shen M, Mattox W. Activation and repression functions of an SR splicing regulator depend on exonic versus intronic-binding position. Nucleic Acids Res 2011; 40:428-37. [PMID: 21914724 PMCID: PMC3245930 DOI: 10.1093/nar/gkr713] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
SR proteins and related factors play widespread roles in alternative pre-mRNA splicing and are known to promote splice site recognition through their Arg–Ser-rich effector domains. However, binding of SR regulators to some targets results in repression of splice sites through a distinct mechanism. Here, we investigate how activated and repressed targets of the Drosophila SR regulator Transformer2 elicit its differing effects on splicing. We find that, like activation, repression affects early steps in the recognition of splice sites and spliceosome assembly. Repositioning of regulatory elements reveals that Tra2 complexes that normally repress splicing from intronic positions activate splicing when located in an exon. Protein tethering experiments demonstrate that this position dependence is an intrinsic property of Tra2 and further show that repression and activation are mediated by separate effector domains of this protein. When other Drosophila SR factors (SF2 and Rbp1) that activate splicing from exonic positions were tethered intronically they failed to either activate or repress splicing. Interestingly, both activities of Tra2 favor the exonic identity of the RNA sequences that encompass its binding sites. This suggests a model in which these two opposite functions act in concert to define both the position and extent of alternatively spliced exons.
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Affiliation(s)
- Manli Shen
- Department of Genetics and Genes & Development Graduate Program, University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
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45
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Sterne-Weiler T, Howard J, Mort M, Cooper DN, Sanford JR. Loss of exon identity is a common mechanism of human inherited disease. Genome Res 2011; 21:1563-71. [PMID: 21750108 DOI: 10.1101/gr.118638.110] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
It is widely accepted that at least 10% of all mutations causing human inherited disease disrupt splice-site consensus sequences. In contrast to splice-site mutations, the role of auxiliary cis-acting elements such as exonic splicing enhancers (ESE) and exonic splicing silencers (ESS) in human inherited disease is still poorly understood. Here we use a top-down approach to determine rates of loss or gain of known human exonic splicing regulatory (ESR) sequences associated with either disease-causing mutations or putatively neutral single nucleotide polymorphisms (SNPs). We observe significant enrichment toward loss of ESEs and gain of ESSs among inherited disease-causing variants relative to neutral polymorphisms, indicating that exon skipping may play a prominent role in aberrant gene regulation. Both computational and biochemical approaches underscore the relevance of exonic splicing enhancer loss and silencer gain in inherited disease. Additionally, we provide direct evidence that both SRp20 (SRSF3) and possibly PTB (PTBP1) are involved in the function of a splicing silencer that is created de novo by a total of 83 different inherited disease mutations in 67 different disease genes. Taken together, we find that ~25% (7154/27,681) of known mis-sense and nonsense disease-causing mutations alter functional splicing signals within exons, suggesting a much more widespread role for aberrant mRNA processing in causing human inherited disease than has hitherto been appreciated.
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Affiliation(s)
- Timothy Sterne-Weiler
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Cruz, Santa Cruz, California 95064, USA
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46
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David CJ, Boyne AR, Millhouse SR, Manley JL. The RNA polymerase II C-terminal domain promotes splicing activation through recruitment of a U2AF65-Prp19 complex. Genes Dev 2011; 25:972-83. [PMID: 21536736 DOI: 10.1101/gad.2038011] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pre-mRNA splicing is frequently coupled to transcription by RNA polymerase II (RNAPII). This coupling requires the C-terminal domain of the RNAPII largest subunit (CTD), although the underlying mechanism is poorly understood. Using a biochemical complementation assay, we previously identified an activity that stimulates CTD-dependent splicing in vitro. We purified this activity and found that it consists of a complex of two well-known splicing factors: U2AF65 and the Prp19 complex (PRP19C). We provide evidence that both U2AF65 and PRP19C are required for CTD-dependent splicing activation, that U2AF65 and PRP19C interact both in vitro and in vivo, and that this interaction is required for activation of splicing. Providing the link to the CTD, we show that U2AF65 binds directly to the phosphorylated CTD, and that this interaction results in increased recruitment of U2AF65 and PRP19C to the pre-mRNA. Our results not only provide a mechanism by which the CTD enhances splicing, but also describe unexpected interactions important for splicing and its coupling to transcription.
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Affiliation(s)
- Charles J David
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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47
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Melia USP, Claria F, Gallardo JJ, Caminal P, Perera A, Vallverdu M. Exons and introns characterization in nucleic acid sequences by time-frequency analysis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2010:1783-6. [PMID: 21096421 DOI: 10.1109/iembs.2010.5626756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A current problem in deoxyribonucleic acid (DNA) sequence analysis is to determine the exact locations of the genes and also in eukaryotes, the protein-coding regions in the mRNA primary transcript (pre-mRNA).The conversion into discrete numerical values of the symbols associated to the nucleotides of these sequences allows for a signal to address the problems related to localization and annotation of genes. In this work, thermodynamic data of free energy changes (ΔG°) on the formation of a duplex structure of DNA or RNA are used to convert the symbols into numerical values associated with the nucleotide sequence pre-mRNA. This study presents an analysis, based on techniques of time-frequency representation of a large number of gene sequences, in order to find variables related to pre-mRNA that could best characterize and discriminate coding regions from non-coding regions. It has been found that instantaneous frequency variables and instantaneous spectral energy variables in different frequency bands, allowed exons and introns to be correctly classified with more than 85%.
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Affiliation(s)
- Umberto S P Melia
- Dept. ESAII, Centre for Biomedical Engineering Research, Universitat Politècnica de Catalunya, CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain.
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48
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Shen H, Zheng X, Luecke S, Green MR. The U2AF35-related protein Urp contacts the 3' splice site to promote U12-type intron splicing and the second step of U2-type intron splicing. Genes Dev 2011; 24:2389-94. [PMID: 21041408 DOI: 10.1101/gad.1974810] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The U2AF35-related protein Urp has been implicated previously in splicing of the major class of U2-type introns. Here we show that Urp is also required for splicing of the minor class of U12-type introns. Urp is recruited in an ATP-dependent fashion to the U12-type intron 3' splice site, where it promotes formation of spliceosomal complexes. Remarkably, Urp also contacts the 3' splice site of a U2-type intron, but in this case is specifically required for the second step of splicing. Thus, through recognition of a common splicing element, Urp facilitates distinct steps of U2- and U12-type intron splicing.
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Affiliation(s)
- Haihong Shen
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.
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49
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Doktor TK, Schroeder LD, Vested A, Palmfeldt J, Andersen HS, Gregersen N, Andresen BS. SMN2 exon 7 splicing is inhibited by binding of hnRNP A1 to a common ESS motif that spans the 3' splice site. Hum Mutat 2011; 32:220-30. [PMID: 21120954 DOI: 10.1002/humu.21419] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 11/02/2010] [Indexed: 11/05/2022]
Abstract
Spinal Muscular Atrophy is caused by homozygous loss of SMN1 with phenotypic modulation by SMN2. SMN2 expresses only limited amounts of full-length transcript due to skipping of exon 7 caused by disruption of an SF2/ASF binding ESE. Additionally, hnRNP A1 has been reported to inhibit inclusion of SMN2 exon 7. We previously reported high similarity between the sequence spanning the 3' ss of SMN1 and SMN2 exon 7 and an hnRNP A1 binding ESS, which regulates MCAD exon 5 splicing. We show here that this 3' ss motif indeed functions as a crucial hnRNP A1 binding ESS, which inhibits inclusion of SMN1/2 exon 7 and is antagonized by the SMN1 ESE, but not by the inactive SMN2 sequence. Pull-down experiments revealed a specific interaction between hnRNP A1 and the 3' ss AG-dinucleotide, which could be disrupted by mutations shown to improve splicing in reporter minigenes. Genomic analyses revealed that in the human genome, 3' ss matching the SMN1/2 ESS motif region are much less abundant than 3' ss with a disrupted ESS motif. This indicates that this ESS may be a general splicing inhibitory motif, which binds hnRNP A1 and inhibits exon inclusion by binding to 3' ss harboring this ESS motif.
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Affiliation(s)
- Thomas Koed Doktor
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
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50
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Xiao X, Lee JH. Systems analysis of alternative splicing and its regulation. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 2:550-565. [PMID: 20836047 DOI: 10.1002/wsbm.84] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Alternative splicing (AS) has emerged as a key mechanism that accounts for gene expression diversity in metazoan organisms. Splicing is tightly regulated by a repertoire of RNA and protein factors and RNA sequence elements that function in a cooperative manner. Systems-level experimental and computational approaches have been instrumental in establishing comprehensive profiles of transcript variants generated by AS. In addition, systems biology approaches are starting to define how combinatorial splicing regulation shapes the complex splicing phenotypes observed in different tissue types and developmental stages and under different conditions. Here, we review recent progress in these areas.
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Affiliation(s)
- Xinshu Xiao
- Department of Physiological Science, University of California, Los Angeles, CA 90095, USA.,Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Jae-Hyung Lee
- Department of Physiological Science, University of California, Los Angeles, CA 90095, USA.,Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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