1
|
Fletcher S, Keegan NP, Mejzini R, Pitout IL. To splice or not to splice: pseudoexons in neurological disease and opportunities for intervention. Curr Opin Genet Dev 2025; 92:102343. [PMID: 40158386 DOI: 10.1016/j.gde.2025.102343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2024] [Revised: 01/28/2025] [Accepted: 03/05/2025] [Indexed: 04/02/2025]
Abstract
Accurate exon selection and processing of pre-messenger RNA are crucial for normal gene expression. Mutations that alter splicing disrupt pre-mRNA processing and can have diverse effects on transcript structure, making the consequences of many such mutations difficult to predict. While next-generation sequencing technologies have transformed genetic diagnosis for many patients, deep intronic variants generally evade detection and characterisation. Of all the known types of splicing mutations, the most elusive to predict are those that activate pseudoexons. Because transcripts that contain pseudoexons are otherwise generally intact, exclusion (or 'skipping') of the pseudoexon during processing of the pre-mRNA is likely to generate a normal, functional mRNA. Characterisation of pseudoexon mutations will open opportunities for the development of antisense oligonucleotide strategies to overcome these disease-causing mutations.
Collapse
Affiliation(s)
- Sue Fletcher
- Personalised Medicine Centre, Health Futures Institute, Murdoch University, 90 South St, Murdoch, WA 6150, Australia; The University of Western Australia Medical School, Perth, WA 6009, Australia.
| | - Niall P Keegan
- Personalised Medicine Centre, Health Futures Institute, Murdoch University, 90 South St, Murdoch, WA 6150, Australia.
| | - Rita Mejzini
- Personalised Medicine Centre, Health Futures Institute, Murdoch University, 90 South St, Murdoch, WA 6150, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia.
| | - Ianthe L Pitout
- Personalised Medicine Centre, Health Futures Institute, Murdoch University, 90 South St, Murdoch, WA 6150, Australia.
| |
Collapse
|
2
|
Naffaa MM, Al-Ewaidat OA, Gogia S, Begiashvili V. Neoantigen-based immunotherapy: advancing precision medicine in cancer and glioblastoma treatment through discovery and innovation. EXPLORATION OF TARGETED ANTI-TUMOR THERAPY 2025; 6:1002313. [PMID: 40309350 PMCID: PMC12040680 DOI: 10.37349/etat.2025.1002313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2025] [Accepted: 04/07/2025] [Indexed: 05/02/2025] Open
Abstract
Neoantigen-based immunotherapy has emerged as a transformative approach in cancer treatment, offering precision medicine strategies that target tumor-specific antigens derived from genetic, transcriptomic, and proteomic alterations unique to cancer cells. These neoantigens serve as highly specific targets for personalized therapies, promising more effective and tailored treatments. The aim of this article is to explore the advances in neoantigen-based therapies, highlighting successful treatments such as vaccines, tumor-infiltrating lymphocyte (TIL) therapy, T-cell receptor-engineered T cells therapy (TCR-T), and chimeric antigen receptor T cells therapy (CAR-T), particularly in cancer types like glioblastoma (GBM). Advances in technologies such as next-generation sequencing, RNA-based platforms, and CRISPR gene editing have accelerated the identification and validation of neoantigens, moving them closer to clinical application. Despite promising results, challenges such as tumor heterogeneity, immune evasion, and resistance mechanisms persist. The integration of AI-driven tools and multi-omic data has refined neoantigen discovery, while combination therapies are being developed to address issues like immune suppression and scalability. Additionally, the article discusses the ongoing development of personalized immunotherapies targeting tumor mutations, emphasizing the need for continued collaboration between computational and experimental approaches. Ultimately, the integration of cutting-edge technologies in neoantigen research holds the potential to revolutionize cancer care, offering hope for more effective and targeted treatments.
Collapse
Affiliation(s)
- Moawiah M Naffaa
- Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ola A Al-Ewaidat
- Department of Internal Medicine, Ascension Saint Francis Hospital, Evanston, IL 60202, USA
| | - Sopiko Gogia
- Department of Internal Medicine, Ascension Saint Francis Hospital, Evanston, IL 60202, USA
| | - Valiko Begiashvili
- Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS 66103, USA
| |
Collapse
|
3
|
Sanjeev M, Woodward LA, Schiff ML, Patton RD, Myers S, Paul D, Bundschuh R, Singh G. PYM1 limits non-canonical Exon Junction Complex occupancy in a gene architecture dependent manner to tune mRNA expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.03.13.643037. [PMID: 40161626 PMCID: PMC11952570 DOI: 10.1101/2025.03.13.643037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 04/02/2025]
Abstract
The Exon Junction Complex (EJC) deposited upstream of exon-exon junctions during pre-mRNA splicing in the nucleus remains stably bound to RNA to modulate mRNA fate at multiple post-transcriptional steps until its disassembly during translation. Here, we investigated two EJC disassembly mechanisms in human embryonic kidney 293 (HEK293) cells, one mediated by PYM1, a factor that can bind both the ribosome and the RBM8A/MAGOH heterodimer of the EJC core, and another by the elongating ribosome itself. We find that EJCs lacking PYM1 interaction show no defect in translation-dependent disassembly but is required for translation-independent EJC destabilization. Surprisingly, PYM1 interaction deficient EJCs are enriched on sites away from the canonical EJC binding position including on transcripts without introns or with fewer and longer exons. Acute reduction of PYM1 levels in HEK293 cells results in a modest inhibition of nonsense-mediated mRNA decay and stabilization of mRNAs that localize to endoplasmic reticulum associated TIS-granules and are characterized by fewer and longer exons. We confirmed the previously reported PYM1-flavivirus capsid protein interaction and found that human cells expressing the capsid protein or infected with flaviviruses show similar changes in gene expression as upon PYM1 depletion. Thus, PYM1 acts as an EJC specificity factor that is hijacked by flaviviruses to alter global EJC occupancy and reshape host cell mRNA regulation.
Collapse
Affiliation(s)
- Manu Sanjeev
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
- Molecular, Cellular and Developmental Biology graduate program, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Lauren A Woodward
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Michael L Schiff
- Department of Physics, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Robert D Patton
- Department of Physics, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Sean Myers
- Department of Physics, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Debadrita Paul
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
- Molecular, Cellular and Developmental Biology graduate program, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Ralf Bundschuh
- Department of Physics, The Ohio State University, Columbus, OH 43210
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Guramrit Singh
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| |
Collapse
|
4
|
Embree CM, Stephanou A, Singh G. Direct and indirect effects of spliceosome disruption compromise gene regulation by Nonsense-Mediated mRNA Decay. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.12.27.630533. [PMID: 39763844 PMCID: PMC11703147 DOI: 10.1101/2024.12.27.630533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2025]
Abstract
Pre-mRNA splicing, carried out in the nucleus by a large ribonucleoprotein machine known as the spliceosome, is functionally and physically coupled to the mRNA surveillance pathway in the cytoplasm called nonsense mediated mRNA decay (NMD). The NMD pathway monitors for premature translation termination signals, which can result from alternative splicing, by relying on the exon junction complex (EJC) deposited on exon-exon junctions by the spliceosome. Recently, multiple genetic screens in human cell lines have identified numerous spliceosome components as putative NMD factors. Using publicly available RNA-seq datasets from K562 and HepG2 cells depleted of 18 different spliceosome components, we find that natural NMD targeted mRNA isoforms are upregulated when members of the catalytic spliceosome are reduced. While some of this increase could be due to widespread pleiotropic effects of spliceosome dysfunction (e.g., reduced expression of NMD factors due to mis-splicing of their mRNAs), we identify that AQR, SF3B1, SF3B4 and CDC40 may have a more direct role in NMD. We also test the hypothesis that increased production of novel NMD substrates may overwhelm the pathway to find a direct correlation between the amount of novel NMD substrates detected and the degree of NMD inhibition observed. Finally, similar transcriptome alterations and NMD substrate upregulation are also observed in cells treated with spliceosome inhibitors and in cells derived from retinitis pigmentosa patients with mutations in PRPF8 and PRPF31. Overall, our results show that regardless of the cause, spliceosome disruption upregulates a broad set of NMD targets, which could contribute to cellular dysfunction in spliceosomopathies.
Collapse
Affiliation(s)
- Caleb M Embree
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University, Columbus, OH, 43210
| | - Andreas Stephanou
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University, Columbus, OH, 43210
| | - Guramrit Singh
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University, Columbus, OH, 43210
| |
Collapse
|
5
|
Fukumura K, Masuda A, Takeda JI, Nagano O, Saya H, Ohno K, Mayeda A. RNPS1 in PSAP complex controls periodic pre-mRNA splicing over the cell cycle. iScience 2024; 27:111400. [PMID: 39687031 PMCID: PMC11648250 DOI: 10.1016/j.isci.2024.111400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 08/30/2024] [Accepted: 11/12/2024] [Indexed: 12/18/2024] Open
Abstract
Cell cycle progression requires periodic gene expression through splicing control. However, the splicing factor that directly controls this cell cycle-dependent splicing remains unknown. Cell cycle-dependent expression of the AURKB (aurora kinase B) gene is essential for chromosome segregation and cytokinesis. We previously reported that RNPS1 is essential to maintain precise splicing in AURKB intron 5. Here we show that RNPS1 plays this role in PSAP complex with PNN and SAP18, but not ASAP complex with ACIN1 and SAP18. Whole-transcriptome sequencing of RNPS1- and PNN-deficient cells indicated that RNPS1, either alone or as PSAP complex, is an essential splicing factor for a subset of introns. Remarkably, protein expression of RNPS1, but not PNN, is coordinated with cyclical splicing in PSAP-controlled introns including AURKB intron 5. The ubiquitin-proteasome pathway is involved in the periodic decrease of RNPS1 protein level. RNPS1 is a key factor that controls periodic splicing during the cell cycle.
Collapse
Affiliation(s)
- Kazuhiro Fukumura
- Division of Gene Regulation, Oncology Innovation Center, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Jun-ichi Takeda
- Division of Neurogenetics, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Osamu Nagano
- Division of Gene Regulation, Oncology Innovation Center, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Hideyuki Saya
- Division of Gene Regulation, Oncology Innovation Center, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Graduate School of Nutritional Sciences, Nagoya University of Arts and Sciences, Nisshin, Aichi 470-0196, Japan
| | - Akila Mayeda
- Division of Gene Regulation, Oncology Innovation Center, Fujita Health University, Toyoake, Aichi 470-1192, Japan
- xFOREST Therapeutics Co., Ltd., Kajii-cho, Kamigyo-ku, Kyoto 602-0841, Japan
| |
Collapse
|
6
|
Li J, Xin Y, Zhang S, Li Y, Jiang M, Zhang S, Yang L, Yang J, Cao P, Lu J. EIF4A3 is stabilized by the long noncoding RNA BC200 to regulate gene expression during Epstein-Barr virus infection. J Med Virol 2024; 96:e29955. [PMID: 39370864 DOI: 10.1002/jmv.29955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 09/11/2024] [Accepted: 09/22/2024] [Indexed: 10/08/2024]
Abstract
Epstein‒Barr virus (EBV) regulates the expression of host genes involved in functional pathways for viral infection and pathogenicity. Long noncoding RNAs (lncRNAs) have been found to be important regulators of cellular biology. However, how EBV affects host biological processes via lncRNAs remains elusive. Eukaryotic initiation factor 4A3 (EIF4A3) was recently identified as an essential controller of cell fate with an unknown role in EBV infection. Here, the expression of lncRNA brain cytoplasmic 200 (BC200) was shown to be significantly upregulated in EBV-infected cell lines. RNA immunoprecipitation and RNA pulldown assays confirmed that BC200 bound to EIF4A3. Moreover, BC200 promoted EIF4A3 expression at the protein level but not at the mRNA level. Mechanistically, BC200 stabilized the EIF4A3 protein by impeding the K48-linked polyubiquitination of the K195 and K198 residues of EIF4A3. In addition, RNA-seq analysis of EBV-positive cells with knockdown of either BC200 or EIF4A3 revealed that a broad range of cellular genes were differentially regulated, particularly those related to virus infection and immune response pathways. This study is the first to reveal the key residues involved in EIF4A3 polyubiquitination and elucidate the novel regulatory role of EBV in host gene expression via the BC200/EIF4A3 axis. These results have implications for the pathogenesis and treatment of EBV-related diseases.
Collapse
Affiliation(s)
- Jing Li
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| | - Yujie Xin
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| | - Siwei Zhang
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Laboratory Medicine Center, Zhuzhou Central Hospital/The Affiliated Zhuzhou Hospital of Xiangya School of Medicine, Central South University, Zhuzhou, China
| | - Yanling Li
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
| | - Mingjuan Jiang
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| | - Senmiao Zhang
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| | - Li Yang
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| | - Jing Yang
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
| | - Pengfei Cao
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| | - Jianhong Lu
- Department of Nuclear Medicine, Hunan Cancer Hospital/the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Department of Microbiology, School of Basic Medical Science, Central South University, Changsha, China
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, NHC Key Laboratory of Carcinogenesis, Cancer Research Institute, Central South University, Changsha, China
- Department of Hematology, Xiangya Hospital, Central South University, Changsha, China
| |
Collapse
|
7
|
Alsina FC, Lupan BM, Lin LJ, Musso CM, Mosti F, Newman CR, Wood LM, Suzuki A, Agostino M, Moore JK, Silver DL. The RNA-binding protein EIF4A3 promotes axon development by direct control of the cytoskeleton. Cell Rep 2024; 43:114666. [PMID: 39182224 PMCID: PMC11488691 DOI: 10.1016/j.celrep.2024.114666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 02/28/2024] [Accepted: 08/06/2024] [Indexed: 08/27/2024] Open
Abstract
The exon junction complex (EJC), nucleated by EIF4A3, is indispensable for mRNA fate and function throughout eukaryotes. We discover that EIF4A3 directly controls microtubules, independent of RNA, which is critical for neural wiring. While neuronal survival in the developing mouse cerebral cortex depends upon an intact EJC, axonal tract development requires only Eif4a3. Using human cortical organoids, we show that EIF4A3 disease mutations also impair neuronal growth, highlighting conserved functions relevant for neurodevelopmental pathology. Live imaging of growing neurons shows that EIF4A3 is essential for microtubule dynamics. Employing biochemistry and competition experiments, we demonstrate that EIF4A3 directly binds to microtubules, mutually exclusive of the EJC. Finally, in vitro reconstitution assays and rescue experiments demonstrate that EIF4A3 is sufficient to promote microtubule polymerization and that EIF4A3-microtubule association is a major contributor to axon growth. This reveals a fundamental mechanism by which neurons re-utilize core gene expression machinery to directly control the cytoskeleton.
Collapse
Affiliation(s)
- Fernando C Alsina
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Bianca M Lupan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Lydia J Lin
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Camila M Musso
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Federica Mosti
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Carly R Newman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Lisa M Wood
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Aussie Suzuki
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, WI, USA
| | - Mark Agostino
- Curtin Health Innovation Research Institute, Curtin Medical School, and Curtin Institute for Computation, Curtin University, Bentley, WA 6102, Australia
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Departments of Cell Biology and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences and Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA.
| |
Collapse
|
8
|
Da Cunha D, Miro J, Van Goethem C, Notarnicola C, Hugon G, Carnac G, Cossée M, Koenig M, Tuffery-Giraud S. The exon junction complex is required for DMD gene splicing fidelity and myogenic differentiation. Cell Mol Life Sci 2024; 81:150. [PMID: 38512499 PMCID: PMC10957711 DOI: 10.1007/s00018-024-05188-1] [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: 09/10/2023] [Revised: 02/14/2024] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
Deposition of the exon junction complex (EJC) upstream of exon-exon junctions helps maintain transcriptome integrity by preventing spurious re-splicing events in already spliced mRNAs. Here we investigate the importance of EJC for the correct splicing of the 2.2-megabase-long human DMD pre-mRNA, which encodes dystrophin, an essential protein involved in cytoskeletal organization and cell signaling. Using targeted RNA-seq, we show that knock-down of the eIF4A3 and Y14 core components of EJC in a human muscle cell line causes an accumulation of mis-splicing events clustered towards the 3' end of the DMD transcript (Dp427m). This deregulation is conserved in the short Dp71 isoform expressed ubiquitously except in adult skeletal muscle and is rescued with wild-type eIF4A3 and Y14 proteins but not with an EJC assembly-defective mutant eIF4A3. MLN51 protein and EJC-associated ASAP/PSAP complexes independently modulate the inclusion of the regulated exons 71 and 78. Our data confirm the protective role of EJC in maintaining splicing fidelity, which in the DMD gene is necessary to preserve the function of the critical C-terminal protein-protein interaction domain of dystrophin present in all tissue-specific isoforms. Given the role of the EJC in maintaining the integrity of dystrophin, we asked whether the EJC could also be involved in the regulation of a mechanism as complex as skeletal muscle differentiation. We found that eIF4A3 knockdown impairs myogenic differentiation by blocking myotube formation. Collectively, our data provide new insights into the functional roles of EJC in human skeletal muscle.
Collapse
Affiliation(s)
- Dylan Da Cunha
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Julie Miro
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Charles Van Goethem
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Montpellier, France
- Montpellier BioInformatique Pour Le Diagnostic Clinique (MOBIDIC), Plateau de Médecine Moléculaire Et Génomique (PMMG), CHU Montpellier, 34295, Montpellier, France
| | | | - Gérald Hugon
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Gilles Carnac
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Mireille Cossée
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Montpellier, France
| | - Michel Koenig
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Montpellier, France
| | | |
Collapse
|
9
|
He PC, He C. mRNA accessibility within mRNPs as a determinant of gene expression. Trends Biochem Sci 2024; 49:199-207. [PMID: 38071089 PMCID: PMC10939938 DOI: 10.1016/j.tibs.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/05/2023] [Accepted: 11/10/2023] [Indexed: 01/31/2024]
Abstract
Gene expression is a complex process requiring many control mechanisms to achieve a desired phenotype. DNA accessibility within chromatin is well established as an important determinant of gene expression. By contrast, while mRNA also associates with a complement of proteins, the exact nature of messenger ribonucleoprotein (mRNP) packaging and its functional relevance is not as clear. Recent reports indicate that exon junction complex (EJC)-mediated mRNP packaging renders exon junction-proximal regions inaccessible for m6A methylation, and that EJCs reside within the inaccessible interior of globular transcription and export (TREX) complex-associated nuclear mRNPs. We propose that 'mRNA accessibility' within mRNPs is an important determinant of gene expression that may modulate the specificity of a broad array of regulatory processes including but not limited to m6A methylation.
Collapse
Affiliation(s)
- P Cody He
- Pritzker School of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
10
|
Lee S, Aubee JI, Lai EC. Regulation of alternative splicing and polyadenylation in neurons. Life Sci Alliance 2023; 6:e202302000. [PMID: 37793776 PMCID: PMC10551640 DOI: 10.26508/lsa.202302000] [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: 02/19/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023] Open
Abstract
Cell-type-specific gene expression is a fundamental feature of multicellular organisms and is achieved by combinations of regulatory strategies. Although cell-restricted transcription is perhaps the most widely studied mechanism, co-transcriptional and post-transcriptional processes are also central to the spatiotemporal control of gene functions. One general category of expression control involves the generation of multiple transcript isoforms from an individual gene, whose balance and cell specificity are frequently tightly regulated via diverse strategies. The nervous system makes particularly extensive use of cell-specific isoforms, specializing the neural function of genes that are expressed more broadly. Here, we review regulatory strategies and RNA-binding proteins that direct neural-specific isoform processing. These include various classes of alternative splicing and alternative polyadenylation events, both of which broadly diversify the neural transcriptome. Importantly, global alterations of splicing and alternative polyadenylation are characteristic of many neural pathologies, and recent genetic studies demonstrate how misregulation of individual neural isoforms can directly cause mutant phenotypes.
Collapse
Affiliation(s)
- Seungjae Lee
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Joseph I Aubee
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Eric C Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| |
Collapse
|
11
|
Morillo L, Paternina T, Alasseur Q, Genovesio A, Schwartz S, Le Hir H. Comprehensive mapping of exon junction complex binding sites reveals universal EJC deposition in Drosophila. BMC Biol 2023; 21:246. [PMID: 37936138 PMCID: PMC10630996 DOI: 10.1186/s12915-023-01749-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/26/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND The exon junction complex (EJC) is involved in most steps of the mRNA life cycle, ranging from splicing to nonsense-mediated mRNA decay (NMD). It is assembled by the splicing machinery onto mRNA in a sequence-independent manner. A fundamental open question is whether the EJC is deposited onto all exon‒exon junctions or only on a subset of them. Several previous studies have made observations supportive of the latter, yet these have been limited by methodological constraints. RESULTS In this study, we sought to overcome these limitations via the integration of two different approaches for transcriptome-wide mapping of EJCs. Our results revealed that nearly all, if not all, internal exons consistently harbor an EJC in Drosophila, demonstrating that EJC presence is an inherent consequence of the splicing reaction. Furthermore, our study underscores the limitations of eCLIP methods in fully elucidating the landscape of RBP binding sites. Our findings highlight how highly specific (low false positive) methodologies can lead to erroneous interpretations due to partial sensitivity (high false negatives). CONCLUSIONS This study contributes to our understanding of EJC deposition and its association with pre-mRNA splicing. The universal presence of EJC on internal exons underscores its significance in ensuring proper mRNA processing. Additionally, our observations highlight the need to consider both specificity and sensitivity in RBP mapping methodologies.
Collapse
Affiliation(s)
- Lucía Morillo
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Toni Paternina
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Quentin Alasseur
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Auguste Genovesio
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Schraga Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7630031, Israel
| | - Hervé Le Hir
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France.
| |
Collapse
|
12
|
Shenasa H, Bentley DL. Pre-mRNA splicing and its cotranscriptional connections. Trends Genet 2023; 39:672-685. [PMID: 37236814 PMCID: PMC10524715 DOI: 10.1016/j.tig.2023.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/23/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023]
Abstract
Transcription of eukaryotic genes by RNA polymerase II (Pol II) yields RNA precursors containing introns that must be spliced out and the flanking exons ligated together. Splicing is catalyzed by a dynamic ribonucleoprotein complex called the spliceosome. Recent evidence has shown that a large fraction of splicing occurs cotranscriptionally as the RNA chain is extruded from Pol II at speeds of up to 5 kb/minute. Splicing is more efficient when it is tethered to the transcription elongation complex, and this linkage permits functional coupling of splicing with transcription. We discuss recent progress that has uncovered a network of connections that link splicing to transcript elongation and other cotranscriptional RNA processing events.
Collapse
Affiliation(s)
- Hossein Shenasa
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - David L Bentley
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA.
| |
Collapse
|
13
|
Mas AM, Goñi E, Ruiz de Los Mozos I, Arcas A, Statello L, González J, Blázquez L, Lee WTC, Gupta D, Sejas Á, Hoshina S, Armaos A, Tartaglia GG, Waga S, Ule J, Rothenberg E, Gómez M, Huarte M. ORC1 binds to cis-transcribed RNAs for efficient activation of replication origins. Nat Commun 2023; 14:4447. [PMID: 37488096 PMCID: PMC10366126 DOI: 10.1038/s41467-023-40105-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/11/2023] [Indexed: 07/26/2023] Open
Abstract
Cells must coordinate the activation of thousands of replication origins dispersed throughout their genome. Active transcription is known to favor the formation of mammalian origins, although the role that RNA plays in this process remains unclear. We show that the ORC1 subunit of the human Origin Recognition Complex interacts with RNAs transcribed from genes with origins in their transcription start sites (TSSs), displaying a positive correlation between RNA binding and origin activity. RNA depletion, or the use of ORC1 RNA-binding mutant, result in inefficient activation of proximal origins, linked to impaired ORC1 chromatin release. ORC1 RNA binding activity resides in its intrinsically disordered region, involved in intra- and inter-molecular interactions, regulation by phosphorylation, and phase-separation. We show that RNA binding favors ORC1 chromatin release, by regulating its phosphorylation and subsequent degradation. Our results unveil a non-coding function of RNA as a dynamic component of the chromatin, orchestrating the activation of replication origins.
Collapse
Affiliation(s)
- Aina Maria Mas
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Enrique Goñi
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Igor Ruiz de Los Mozos
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Aida Arcas
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Luisa Statello
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Jovanna González
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Lorea Blázquez
- RNA Networks Lab, The Francis Crick Institute, NW11BF, London, UK
- Neurosciences Area, Biodonostia Health Research Institute, 20014, San Sebastian, Spain
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Wei Ting Chelsea Lee
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, NY, 10016, USA
| | - Dipika Gupta
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, NY, 10016, USA
| | - Álvaro Sejas
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Shoko Hoshina
- Department of Chemical and Biological Sciences, Japan Women's University, Tokyo, 112-8681, Japan
| | - Alexandros Armaos
- Center for Human Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Gian Gaetano Tartaglia
- Center for Human Technologies, Istituto Italiano di Tecnologia, Genova, Italy
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Department of Biology 'Charles Darwin', Sapienza University of Rome, Rome, Italy
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Shou Waga
- Department of Chemical and Biological Sciences, Japan Women's University, Tokyo, 112-8681, Japan
| | - Jernej Ule
- RNA Networks Lab, The Francis Crick Institute, NW11BF, London, UK
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, NY, 10016, USA
| | - María Gómez
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049, Madrid, Spain
| | - Maite Huarte
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain.
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain.
| |
Collapse
|
14
|
Hoppe ER, Udy DB, Bradley RK. Recursive splicing discovery using lariats in total RNA sequencing. Life Sci Alliance 2023; 6:e202201889. [PMID: 37137707 PMCID: PMC10156609 DOI: 10.26508/lsa.202201889] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/05/2023] Open
Abstract
Recursive splicing is a non-canonical splicing mechanism in which an intron is removed in segments via multiple splicing reactions. Relatively few recursive splice sites have been identified with high confidence in human introns, and more comprehensive analyses are needed to better characterize where recursive splicing happens and whether or not it has a regulatory function. In this study, we use an unbiased approach using intron lariats to search for recursive splice sites in constitutive introns and alternative exons in the human transcriptome. We find evidence for recursive splicing in a broader range of intron sizes than previously reported and detail a new location for recursive splicing at the distal ends of cassette exons. In addition, we identify evidence for the conservation of these recursive splice sites among higher vertebrates and the use of these sites to influence alternative exon exclusion. Together, our data demonstrate the prevalence of recursive splicing and its potential influence on gene expression through alternatively spliced isoforms.
Collapse
Affiliation(s)
- Emma R Hoppe
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Dylan B Udy
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| |
Collapse
|
15
|
Gohr A, Iñiguez LP, Torres-Méndez A, Bonnal S, Irimia M. Insplico: effective computational tool for studying splicing order of adjacent introns genome-wide with short and long RNA-seq reads. Nucleic Acids Res 2023; 51:e56. [PMID: 37026474 PMCID: PMC10250204 DOI: 10.1093/nar/gkad244] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 03/13/2023] [Accepted: 03/23/2023] [Indexed: 04/08/2023] Open
Abstract
Although splicing occurs largely co-transcriptionally, the order by which introns are removed does not necessarily follow the order in which they are transcribed. Whereas several genomic features are known to influence whether or not an intron is spliced before its downstream neighbor, multiple questions related to adjacent introns' splicing order (AISO) remain unanswered. Here, we present Insplico, the first standalone software for quantifying AISO that works with both short and long read sequencing technologies. We first demonstrate its applicability and effectiveness using simulated reads and by recapitulating previously reported AISO patterns, which unveiled overlooked biases associated with long read sequencing. We next show that AISO around individual exons is remarkably constant across cell and tissue types and even upon major spliceosomal disruption, and it is evolutionarily conserved between human and mouse brains. We also establish a set of universal features associated with AISO patterns across various animal and plant species. Finally, we used Insplico to investigate AISO in the context of tissue-specific exons, particularly focusing on SRRM4-dependent microexons. We found that the majority of such microexons have non-canonical AISO, in which the downstream intron is spliced first, and we suggest two potential modes of SRRM4 regulation of microexons related to their AISO and various splicing-related features. Insplico is available on gitlab.com/aghr/insplico.
Collapse
Affiliation(s)
- André Gohr
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Luis P Iñiguez
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Antonio Torres-Méndez
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Sophie Bonnal
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Manuel Irimia
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- ICREA, Barcelona, Spain
| |
Collapse
|
16
|
He PC, Wei J, Dou X, Harada BT, Zhang Z, Ge R, Liu C, Zhang LS, Yu X, Wang S, Lyu R, Zou Z, Chen M, He C. Exon architecture controls mRNA m 6A suppression and gene expression. Science 2023; 379:677-682. [PMID: 36705538 PMCID: PMC9990141 DOI: 10.1126/science.abj9090] [Citation(s) in RCA: 117] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 01/16/2023] [Indexed: 01/28/2023]
Abstract
N6-methyladenosine (m6A) is the most abundant messenger RNA (mRNA) modification and plays crucial roles in diverse physiological processes. Using a massively parallel assay for m6A (MPm6A), we discover that m6A specificity is globally regulated by suppressors that prevent m6A deposition in unmethylated transcriptome regions. We identify exon junction complexes (EJCs) as m6A suppressors that protect exon junction-proximal RNA within coding sequences from methylation and regulate mRNA stability through m6A suppression. EJC suppression of m6A underlies multiple global characteristics of mRNA m6A specificity, with the local range of EJC protection sufficient to suppress m6A deposition in average-length internal exons but not in long internal and terminal exons. EJC-suppressed methylation sites colocalize with EJC-suppressed splice sites, which suggests that exon architecture broadly determines local mRNA accessibility to regulatory complexes.
Collapse
Affiliation(s)
- P. Cody He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Jiangbo Wei
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaoyang Dou
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Bryan T. Harada
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Zijie Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
- State Key Laboratory for Conservation and Utilization of Bio-Resources, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, China
| | - Ruiqi Ge
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Chang Liu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Li-Sheng Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xianbin Yu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Shuai Wang
- Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA
| | - Ruitu Lyu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Zhongyu Zou
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Mengjie Chen
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
- Section of Genetic Medicine, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
17
|
Koh E, Shin D, Kim KS. Exon definitive regions for MPC1 microexon splicing and its usage for splicing modulation. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:398-410. [PMID: 36817727 PMCID: PMC9929638 DOI: 10.1016/j.omtn.2023.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/20/2023] [Indexed: 01/26/2023]
Abstract
Alternative splicing of microexons (3-30 base pairs [bp]) is involved in important biological processes in brain development and human cancers. However, understanding a splicing process of non-3x bp microexons is scarce. We showed that 4 bp microexon of mitochondrial pyruvate carrier1 (MPC1) is constitutively included in mRNA. Based on our studies with minigene and exon island constructs, we found the strong exon definition region in the proximal introns bordering MPC1 microexon. Ultimately, we defined a nucleotide fragment from the 3'ss 67 bp of MPC1 microexon to the 5'ss consensus sequence, as a core exon island, which can concatenate its microexon and neighboring exons by splicing. Furthermore, we showed that insertion of the core exon island into a target exon or intron induced skip the target exon or enhance the splicing of an adjacent exon, respectively. Collectively, we suggest that the exon island derived from MPC1 microexon modifies genuine splicing patterns depending on its position, thereby providing insights on strategies for splicing-mediated gene correction.
Collapse
Affiliation(s)
- Eunjin Koh
- Department of Biochemistry and Molecular Biology, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Daye Shin
- Department of Biochemistry and Molecular Biology, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Kyung-Sup Kim
- Department of Biochemistry and Molecular Biology, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 03722, Korea,Corresponding author: Kyung-Sup Kim, Department of Biochemistry and Molecular Biology, Institute of Genetic Science, College of Medicine, Yonsei University, Seoul 03722, Korea.
| |
Collapse
|
18
|
Horn T, Gosliga A, Li C, Enculescu M, Legewie S. Position-dependent effects of RNA-binding proteins in the context of co-transcriptional splicing. NPJ Syst Biol Appl 2023; 9:1. [PMID: 36653378 PMCID: PMC9849329 DOI: 10.1038/s41540-022-00264-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 12/08/2022] [Indexed: 01/19/2023] Open
Abstract
Alternative splicing is an important step in eukaryotic mRNA pre-processing which increases the complexity of gene expression programs, but is frequently altered in disease. Previous work on the regulation of alternative splicing has demonstrated that splicing is controlled by RNA-binding proteins (RBPs) and by epigenetic DNA/histone modifications which affect splicing by changing the speed of polymerase-mediated pre-mRNA transcription. The interplay of these different layers of splicing regulation is poorly understood. In this paper, we derived mathematical models describing how splicing decisions in a three-exon gene are made by combinatorial spliceosome binding to splice sites during ongoing transcription. We additionally take into account the effect of a regulatory RBP and find that the RBP binding position within the sequence is a key determinant of how RNA polymerase velocity affects splicing. Based on these results, we explain paradoxical observations in the experimental literature and further derive rules explaining why the same RBP can act as inhibitor or activator of cassette exon inclusion depending on its binding position. Finally, we derive a stochastic description of co-transcriptional splicing regulation at the single-cell level and show that splicing outcomes show little noise and follow a binomial distribution despite complex regulation by a multitude of factors. Taken together, our simulations demonstrate the robustness of splicing outcomes and reveal that quantitative insights into kinetic competition of co-transcriptional events are required to fully understand this important mechanism of gene expression diversity.
Collapse
Affiliation(s)
- Timur Horn
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Alison Gosliga
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
- University of Stuttgart, Department of Systems Biology and Stuttgart Research Center Systems Biology (SRCSB), Allmandring 31, 70569, Stuttgart, Germany
| | - Congxin Li
- University of Stuttgart, Department of Systems Biology and Stuttgart Research Center Systems Biology (SRCSB), Allmandring 31, 70569, Stuttgart, Germany
| | - Mihaela Enculescu
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
| | - Stefan Legewie
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
- University of Stuttgart, Department of Systems Biology and Stuttgart Research Center Systems Biology (SRCSB), Allmandring 31, 70569, Stuttgart, Germany.
| |
Collapse
|
19
|
Soederberg A, Meißgeier T, Bosserhoff AK, Linck-Paulus L. MAGOH and MAGOHB Knockdown in Melanoma Cells Decreases Nonsense-Mediated Decay Activity and Promotes Apoptosis via Upregulation of GADD45A. Cells 2022; 11:cells11233859. [PMID: 36497117 PMCID: PMC9738831 DOI: 10.3390/cells11233859] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
Cutaneous malignant melanoma is a highly proliferative and aggressive skin cancer with a steadily increasing incidence and a low long-term survival rate after metastatic progression. The protein MAGOH and its highly identical homologue MAGOHB are core components of the exon junction complex (EJC), which regulates splicing, stability and translation of mRNAs. The EJC, and especially MAGOH, has been shown to be involved in the development and progression of several cancers. In melanoma, the expression and function of both homologues remain essentially unexplored. This study identifies high MAGOH and MAGOHB protein expression in cutaneous melanoma cell lines and patient derived tissue samples. An siRNA-mediated knockdown of MAGOH significantly inhibits melanoma cell proliferation. The loss of MAGOH does not affect cell cycle progression, but induces apoptosis, an effect that is enhanced by a simultaneous knockdown of MAGOH and MAGOHB. MAGOH and MAGOHB do not influence the expression of the pro-apoptotic protein Bcl-XS or exon skipping. However, the knockdown of MAGOH and MAGOHB strongly decreases nonsense-mediated decay (NMD) activity, leading to an upregulation of the pro-apoptotic protein GADD45A. In conclusion, simultaneous inhibition of MAGOH and MAGOHB expression substantially affects cell survival, indicating both MAGOH homologues as promising new targets for the treatment of melanoma.
Collapse
Affiliation(s)
- Agnes Soederberg
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Fahrstraße 17, 91054 Erlangen, Germany
| | - Tina Meißgeier
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Fahrstraße 17, 91054 Erlangen, Germany
| | - Anja Katrin Bosserhoff
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Fahrstraße 17, 91054 Erlangen, Germany
- Comprehensive Cancer Center (CCC) Erlangen-EMN, 91054 Erlangen, Germany
| | - Lisa Linck-Paulus
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Fahrstraße 17, 91054 Erlangen, Germany
- Correspondence:
| |
Collapse
|
20
|
Schlautmann LP, Lackmann JW, Altmüller J, Dieterich C, Boehm V, Gehring N. Exon junction complex-associated multi-adapter RNPS1 nucleates splicing regulatory complexes to maintain transcriptome surveillance. Nucleic Acids Res 2022; 50:5899-5918. [PMID: 35640609 PMCID: PMC9178013 DOI: 10.1093/nar/gkac428] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 05/05/2022] [Accepted: 05/10/2022] [Indexed: 12/04/2022] Open
Abstract
The exon junction complex (EJC) is an RNA-binding multi-protein complex with critical functions in post-transcriptional gene regulation. It is deposited on the mRNA during splicing and regulates diverse processes including pre-mRNA splicing and nonsense-mediated mRNA decay (NMD) via various interacting proteins. The peripheral EJC-binding protein RNPS1 was reported to serve two insufficiently characterized functions: suppressing mis-splicing of cryptic splice sites and activating NMD in the cytoplasm. The analysis of transcriptome-wide effects of EJC and RNPS1 knockdowns in different human cell lines supports the conclusion that RNPS1 can moderately influence NMD activity, but is not a globally essential NMD factor. However, numerous aberrant splicing events strongly suggest that the main function of RNPS1 is splicing regulation. Rescue analyses revealed that the RRM and C-terminal domain of RNPS1 both contribute partially to regulate RNPS1-dependent splicing events. We defined the RNPS1 core interactome using complementary immunoprecipitations and proximity labeling, which identified interactions with splicing-regulatory factors that are dependent on the C-terminus or the RRM domain of RNPS1. Thus, RNPS1 emerges as a multifunctional splicing regulator that promotes correct and efficient splicing of different vulnerable splicing events via the formation of diverse splicing-promoting complexes.
Collapse
Affiliation(s)
- Lena P Schlautmann
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Jan-Wilm Lackmann
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Volker Boehm
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| |
Collapse
|
21
|
Kim YJ, Nomakuchi T, Papaleonidopoulou F, Yang L, Zhang Q, Krainer AR. Gene-specific nonsense-mediated mRNA decay targeting for cystic fibrosis therapy. Nat Commun 2022; 13:2978. [PMID: 35624092 PMCID: PMC9142507 DOI: 10.1038/s41467-022-30668-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 05/06/2022] [Indexed: 12/20/2022] Open
Abstract
Low CFTR mRNA expression due to nonsense-mediated mRNA decay (NMD) is a major hurdle in developing a therapy for cystic fibrosis (CF) caused by the W1282X mutation in the CFTR gene. CFTR-W1282X truncated protein retains partial function, so increasing its levels by inhibiting NMD of its mRNA will likely be beneficial. Because NMD regulates the normal expression of many genes, gene-specific stabilization of CFTR-W1282X mRNA expression is more desirable than general NMD inhibition. Synthetic antisense oligonucleotides (ASOs) designed to prevent binding of exon junction complexes (EJC) downstream of premature termination codons (PTCs) attenuate NMD in a gene-specific manner. We describe cocktails of three ASOs that specifically increase the expression of CFTR-W1282X mRNA and CFTR protein upon delivery into human bronchial epithelial cells. This treatment increases the CFTR-mediated chloride current. These results set the stage for clinical development of an allele-specific therapy for CF caused by the W1282X mutation. The W1282X nonsense mutation in the CFTR gene causes cystic fibrosis by reducing its mRNA and functional protein levels. Here the authors developed antisense-oligonucleotide cocktails that restore CFTR protein function by gene-specific stabilization of CFTR mRNA.
Collapse
Affiliation(s)
- Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Tomoki Nomakuchi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA.,Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Foteini Papaleonidopoulou
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Francis Crick Institute, London, 1140062, UK
| | - Lucia Yang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Qian Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
| |
Collapse
|
22
|
The Physiological Roles of the Exon Junction Complex in Development and Diseases. Cells 2022; 11:cells11071192. [PMID: 35406756 PMCID: PMC8997533 DOI: 10.3390/cells11071192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/19/2022] [Accepted: 03/24/2022] [Indexed: 01/12/2023] Open
Abstract
The exon junction complex (EJC) becomes an increasingly important regulator of early gene expression in the central nervous system (CNS) and other tissues. The EJC is comprised of three core proteins: RNA-binding motif 8A (RBM8A), Mago homolog (MAGOH), eukaryotic initiation factor 4A3 (EIF4A3), and a peripheral EJC factor, metastatic lymph node 51 (MLN51), together with various auxiliary factors. The EJC is assembled specifically at exon-exon junctions on mRNAs, hence the name of the complex. The EJC regulates multiple levels of gene expression, from splicing to translation and mRNA degradation. The functional roles of the EJC have been established as crucial to the normal progress of embryonic and neurological development, with wide ranging implications on molecular, cellular, and organism level function. Dysfunction of the EJC has been implicated in multiple developmental and neurological diseases. In this review, we discuss recent progress on the EJC’s physiological roles.
Collapse
|
23
|
Pitolli C, Marini A, Sette C, Pagliarini V. Non-Canonical Splicing and Its Implications in Brain Physiology and Cancer. Int J Mol Sci 2022; 23:ijms23052811. [PMID: 35269953 PMCID: PMC8911335 DOI: 10.3390/ijms23052811] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023] Open
Abstract
The advance of experimental and computational techniques has allowed us to highlight the existence of numerous different mechanisms of RNA maturation, which have been so far unknown. Besides canonical splicing, consisting of the removal of introns from pre-mRNA molecules, non-canonical splicing events may occur to further increase the regulatory and coding potential of the human genome. Among these, splicing of microexons, recursive splicing and biogenesis of circular and chimeric RNAs through back-splicing and trans-splicing processes, respectively, all contribute to expanding the repertoire of RNA transcripts with newly acquired regulatory functions. Interestingly, these non-canonical splicing events seem to occur more frequently in the central nervous system, affecting neuronal development and differentiation programs with important implications on brain physiology. Coherently, dysregulation of non-canonical RNA processing events is associated with brain disorders, including brain tumours. Herein, we summarize the current knowledge on molecular and regulatory mechanisms underlying canonical and non-canonical splicing events with particular emphasis on cis-acting elements and trans-acting factors that all together orchestrate splicing catalysis reactions and decisions. Lastly, we review the impact of non-canonical splicing on brain physiology and pathology and how unconventional splicing mechanisms may be targeted or exploited for novel therapeutic strategies in cancer.
Collapse
Affiliation(s)
- Consuelo Pitolli
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Alberto Marini
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (C.P.); (C.S.)
- GSTEP-Organoids Research Core Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy;
- Correspondence:
| |
Collapse
|
24
|
Moon S, Zhao YT. Recursive splicing is a rare event in the mouse brain. PLoS One 2022; 17:e0263082. [PMID: 35089962 PMCID: PMC8797253 DOI: 10.1371/journal.pone.0263082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/11/2022] [Indexed: 11/18/2022] Open
Abstract
Recursive splicing (RS) is a splicing mechanism to remove long introns from messenger RNA precursors of long genes. Compared to the hundreds of RS events identified in humans and drosophila, only ten RS events have been reported in mice. To further investigate RS in mice, we analyzed RS in the mouse brain, a tissue that is enriched in the expression of long genes. We found that nuclear total RNA sequencing is an efficient approach to investigate RS events. We analyzed 1.15 billion uniquely mapped reads from the nuclear total RNA sequencing data in the mouse cerebral cortex. Unexpectedly, we only identified 20 RS sites, suggesting that RS is a rare event in the mouse brain. We also identified that RS is constitutive between excitatory and inhibitory neurons and between sexes in the mouse cerebral cortex. In addition, we found that the primary sequence context is associated with RS splicing intermediates and distinguishes RS AGGT site from non-RS AGGT sites, indicating the importance of the primary sequence context in RS sites. Moreover, we discovered that cryptic exons may use an RS-like mechanism for splicing. Overall, we provide novel findings about RS in long genes in the mouse brain.
Collapse
Affiliation(s)
- Sohyun Moon
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, United States of America
| | - Ying-Tao Zhao
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, United States of America
- * E-mail:
| |
Collapse
|
25
|
Keegan NP, Wilton SD, Fletcher S. Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 12:806946. [PMID: 35140743 PMCID: PMC8819188 DOI: 10.3389/fgene.2021.806946] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/09/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding pre-mRNA splicing is crucial to accurately diagnosing and treating genetic diseases. However, mutations that alter splicing can exert highly diverse effects. Of all the known types of splicing mutations, perhaps the rarest and most difficult to predict are those that activate pseudoexons, sometimes also called cryptic exons. Unlike other splicing mutations that either destroy or redirect existing splice events, pseudoexon mutations appear to create entirely new exons within introns. Since exon definition in vertebrates requires coordinated arrangements of numerous RNA motifs, one might expect that pseudoexons would only arise when rearrangements of intronic DNA create novel exons by chance. Surprisingly, although such mutations do occur, a far more common cause of pseudoexons is deep-intronic single nucleotide variants, raising the question of why these latent exon-like tracts near the mutation sites have not already been purged from the genome by the evolutionary advantage of more efficient splicing. Possible answers may lie in deep intronic splicing processes such as recursive splicing or poison exon splicing. Because these processes utilize intronic motifs that benignly engage with the spliceosome, the regions involved may be more susceptible to exonization than other intronic regions would be. We speculated that a comprehensive study of reported pseudoexons might detect alignments with known deep intronic splice sites and could also permit the characterisation of novel pseudoexon categories. In this report, we present and analyse a catalogue of over 400 published pseudoexon splice events. In addition to confirming prior observations of the most common pseudoexon mutation types, the size of this catalogue also enabled us to suggest new categories for some of the rarer types of pseudoexon mutation. By comparing our catalogue against published datasets of non-canonical splice events, we also found that 15.7% of pseudoexons exhibit some splicing activity at one or both of their splice sites in non-mutant cells. Importantly, this included seven examples of experimentally confirmed recursive splice sites, confirming for the first time a long-suspected link between these two splicing phenomena. These findings have the potential to improve the fidelity of genetic diagnostics and reveal new targets for splice-modulating therapies.
Collapse
Affiliation(s)
- Niall P. Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| |
Collapse
|
26
|
Ho CH, Paolantoni C, Bawankar P, Tang Z, Brown S, Roignant J, Treisman JE. An exon junction complex-independent function of Barentsz in neuromuscular synapse growth. EMBO Rep 2022; 23:e53231. [PMID: 34726300 PMCID: PMC8728599 DOI: 10.15252/embr.202153231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 01/07/2023] Open
Abstract
The exon junction complex controls the translation, degradation, and localization of spliced mRNAs, and three of its core subunits also play a role in splicing. Here, we show that a fourth subunit, Barentsz, has distinct functions within and separate from the exon junction complex in Drosophila neuromuscular development. The distribution of mitochondria in larval muscles requires Barentsz as well as other exon junction complex subunits and is not rescued by a Barentsz transgene in which residues required for binding to the core subunit eIF4AIII are mutated. In contrast, interactions with the exon junction complex are not required for Barentsz to promote the growth of neuromuscular synapses. We find that the Activin ligand Dawdle shows reduced expression in barentsz mutants and acts downstream of Barentsz to control synapse growth. Both barentsz and dawdle are required in motor neurons, muscles, and glia for normal synapse growth, and exogenous Dawdle can rescue synapse growth in the absence of barentsz. These results identify a biological function for Barentsz that is independent of the exon junction complex.
Collapse
Affiliation(s)
- Cheuk Hei Ho
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
| | - Chiara Paolantoni
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
| | - Praveen Bawankar
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Zuojian Tang
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
Computational Biology at Ridgefield US, Global Computational Biology and Digital ScienceBoehringer IngelheimRidgefieldCTUSA
| | - Stuart Brown
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
ExxonMobil Corporate Strategic ResearchAnnandaleNJUSA
| | - Jean‐Yves Roignant
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Jessica E Treisman
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
| |
Collapse
|
27
|
Larizza L, Calzari L, Alari V, Russo S. Genes for RNA-binding proteins involved in neural-specific functions and diseases are downregulated in Rubinstein-Taybi iNeurons. Neural Regen Res 2022; 17:5-14. [PMID: 34100419 PMCID: PMC8451555 DOI: 10.4103/1673-5374.314286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Taking advantage of the fast-growing knowledge of RNA-binding proteins (RBPs) we review the signature of downregulated genes for RBPs in the transcriptome of induced pluripotent stem cell neurons (iNeurons) modelling the neurodevelopmental Rubinstein Taybi Syndrome (RSTS) caused by mutations in the genes encoding CBP/p300 acetyltransferases. We discuss top and functionally connected downregulated genes sorted to “RNA processing” and “Ribonucleoprotein complex biogenesis” Gene Ontology clusters. The first set of downregulated RBPs includes members of hnRNHP (A1, A2B1, D, G, H2-H1, MAGOHB, PAPBC), core subunits of U small nuclear ribonucleoproteins and Serine-Arginine splicing regulators families, acting in precursor messenger RNA alternative splicing and processing. Consistent with literature findings on reduced transcript levels of serine/arginine repetitive matrix 4 (SRRM4) protein, the main regulator of the neural-specific microexons splicing program upon depletion of Ep300 and Crebbp in mouse neurons, RSTS iNeurons show downregulated genes for proteins impacting this network. We link downregulated genes to neurological disorders including the new HNRNPH1-related intellectual disability syndrome with clinical overlap to RSTS. The set of downregulated genes for Ribosome biogenesis includes several components of ribosomal subunits and nucleolar proteins, such NOP58 and fibrillarin that form complexes with snoRNAs with a central role in guiding post-transcriptional modifications needed for rRNA maturation. These nucleolar proteins are “dual” players as fibrillarin is also required for epigenetic regulation of ribosomal genes and conversely NOP58-associated snoRNA levels are under the control of NOP58 interactor BMAL1, a transcriptional regulator of the circadian rhythm. Additional downregulated genes for “dual specificity” RBPs such as RUVBL1 and METTL1 highlight the links between chromatin and the RBP-ome and the contribution of perturbations in their cross-talk to RSTS. We underline the hub position of CBP/p300 in chromatin regulation, the impact of its defect on neurons’ post-transcriptional regulation of gene expression and the potential use of epidrugs in therapeutics of RBP-caused neurodevelopmental disorders.
Collapse
Affiliation(s)
- Lidia Larizza
- Cytogenetics and Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Luciano Calzari
- Cytogenetics and Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Valentina Alari
- Cytogenetics and Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| | - Silvia Russo
- Cytogenetics and Molecular Genetics Laboratory, IRCCS Istituto Auxologico Italiano, Milano, Italy
| |
Collapse
|
28
|
Rafiee MR, Zagalak JA, Sidorov S, Steinhauser S, Davey K, Ule J, Luscombe NM. Chromatin-contact atlas reveals disorder-mediated protein interactions and moonlighting chromatin-associated RBPs. Nucleic Acids Res 2021; 49:13092-13107. [PMID: 34871434 PMCID: PMC8682780 DOI: 10.1093/nar/gkab1180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/05/2021] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
RNA-binding proteins (RBPs) play diverse roles in regulating co-transcriptional RNA-processing and chromatin functions, but our knowledge of the repertoire of chromatin-associated RBPs (caRBPs) and their interactions with chromatin remains limited. Here, we developed SPACE (Silica Particle Assisted Chromatin Enrichment) to isolate global and regional chromatin components with high specificity and sensitivity, and SPACEmap to identify the chromatin-contact regions in proteins. Applied to mouse embryonic stem cells, SPACE identified 1459 chromatin-associated proteins, ∼48% of which are annotated as RBPs, indicating their dual roles in chromatin and RNA-binding. Additionally, SPACEmap stringently verified chromatin-binding of 403 RBPs and identified their chromatin-contact regions. Notably, SPACEmap showed that about 40% of the caRBPs bind chromatin by intrinsically disordered regions (IDRs). Studying SPACE and total proteome dynamics from mES cells grown in 2iL and serum medium indicates significant correlation (R = 0.62). One of the most dynamic caRBPs is Dazl, which we find co-localized with PRC2 at transcription start sites of genes that are distinct from Dazl mRNA binding. Dazl and other PRC2-colocalised caRBPs are rich in intrinsically disordered regions (IDRs), which could contribute to the formation and regulation of phase-separated PRC condensates. Together, our approach provides an unprecedented insight into IDR-mediated interactions and caRBPs with moonlighting functions in native chromatin.
Collapse
Affiliation(s)
| | - Julian A Zagalak
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | | | | | - Karen Davey
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jernej Ule
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK.,National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Nicholas M Luscombe
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK.,UCL Genetics Institute, University College London, Gower Street, London WC1E 6BT, UK.,Okinawa Institute of Science & Technology Graduate University, Okinawa 904-0495, Japan
| |
Collapse
|
29
|
Xue C, Gu X, Li G, Bao Z, Li L. Expression and Functional Roles of Eukaryotic Initiation Factor 4A Family Proteins in Human Cancers. Front Cell Dev Biol 2021; 9:711965. [PMID: 34869305 PMCID: PMC8640450 DOI: 10.3389/fcell.2021.711965] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 11/05/2021] [Indexed: 01/11/2023] Open
Abstract
The dysregulation of mRNA translation is common in malignancies and may lead to tumorigenesis and progression. Eukaryotic initiation factor 4A (eIF4A) proteins are essential for translation, exhibit bidirectional RNA helicase function, and act as RNA-dependent ATPases. In this review, we explored the predicted structures of the three eIF4A isoforms (eIF4A1, eIF4A2, and eIF4A3), and discussed possible explanations for which function during different translation stages (initiation, mRNA localization, export, and mRNA splicing). These proteins also frequently served as targets of microRNAs (miRNAs) or long noncoding RNAs (lncRNAs) to mediate epithelial-mesenchymal transition (EMT), which was associated with tumor cell invasion and metastasis. To define the differential expression of eIF4A family members, we applied the Tumor Immune Estimation Resource website. We figured out that the eIF4A family genes were differently expressed in specific cancer types. We also found that the level of the eIF4A family genes were associated with abundant immune cells infiltration and tumor purity. The associations between eIF4A proteins and cancer patient clinicopathological features suggested that eIF4A proteins might serve as biomarkers for early tumor diagnosis, histological classification, and clinical grading/staging, providing new tools for precise and individualized cancer treatment.
Collapse
Affiliation(s)
- Chen Xue
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xinyu Gu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Ganglei Li
- Department of Neurosurgery, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Zhengyi Bao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| |
Collapse
|
30
|
eIF4A3 regulates the TFEB-mediated transcriptional response via GSK3B to control autophagy. Cell Death Differ 2021; 28:3344-3356. [PMID: 34158631 PMCID: PMC8630043 DOI: 10.1038/s41418-021-00822-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 02/06/2023] Open
Abstract
During autophagy, the coordinated actions of autophagosomes and lysosomes result in the controlled removal of damaged intracellular organelles and superfluous substrates. The evolutionary conservation of this process and its requirement for maintaining cellular homeostasis emphasizes the need to better dissect the pathways governing its molecular regulation. In our previously performed high-content screen, we assessed the effect of 1530 RNA-binding proteins on autophagy. Among the top regulators, we identified the eukaryotic translation initiation factor 4A-3 (eIF4A3). Here we show that depletion of eIF4A3 leads to a potent increase in autophagosome and lysosome biogenesis and an enhanced autophagic flux. This is mediated by the key autophagy transcription factor, TFEB, which becomes dephosphorylated and translocates from the cytoplasm to the nucleus where it elicits an integrated transcriptional response. We further identified an exon-skipping event in the transcript encoding for the direct TFEB kinase, GSK3B, which leads to a reduction in GSK3B expression and activity. Through analysis of TCGA data, we found a significant upregulation of eIF4A3 expression across several cancer types and confirmed the potential relevance of this newly identified signaling axis in human tumors. Hence, our data suggest a previously unrecognized role for eIF4A3 as a gatekeeper of autophagy through the control of TFEB activation, revealing a new mechanism for autophagy regulation.
Collapse
|
31
|
A genetically-encoded crosslinker screen identifies SERBP1 as a PKCε substrate influencing translation and cell division. Nat Commun 2021; 12:6934. [PMID: 34836941 PMCID: PMC8626422 DOI: 10.1038/s41467-021-27189-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/08/2021] [Indexed: 01/09/2023] Open
Abstract
The PKCε-regulated genome protective pathway provides transformed cells a failsafe to successfully complete mitosis. Despite the necessary role for Aurora B in this programme, it is unclear whether its requirement is sufficient or if other PKCε cell cycle targets are involved. To address this, we developed a trapping strategy using UV-photocrosslinkable amino acids encoded in the PKCε kinase domain. The validation of the mRNA binding protein SERBP1 as a PKCε substrate revealed a series of mitotic events controlled by the catalytic form of PKCε. PKCε represses protein translation, altering SERBP1 binding to the 40 S ribosomal subunit and promoting the assembly of ribonucleoprotein granules containing SERBP1, termed M-bodies. Independent of Aurora B, SERBP1 is shown to be necessary for chromosome segregation and successful cell division, correlating with M-body formation. This requirement for SERBP1 demonstrates that Aurora B acts in concert with translational regulation in the PKCε-controlled pathway exerting genome protection.
Collapse
|
32
|
Joseph B, Scala C, Kondo S, Lai EC. Molecular and genetic dissection of recursive splicing. Life Sci Alliance 2021; 5:5/1/e202101063. [PMID: 34759052 PMCID: PMC8605326 DOI: 10.26508/lsa.202101063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 11/24/2022] Open
Abstract
Intronic ratchet points (RPs) are abundant within long introns in the Drosophila genome and consist of juxtaposed splice acceptor and splice donor (SD) sites. Although they appear to encompass zero-nucleotide exons, we recently clarified that intronic recursive splicing (RS) requires a cryptic exon at the RP (an RS-exon), which is subsequently always skipped and thus absent from mRNA. In addition, Drosophila encodes a smaller set of expressed exons bearing features of RS. Here, we investigate mechanisms that regulate the choice between RP and RS-exon SDs. First, analysis of Drosophila RP SD mutants demonstrates that SD competition suppresses inclusion of cryptic exons in endogenous contexts. Second, characterization of RS-exon reporters implicates exonic sequences as influencing choice of RS-exon usage. Using RS-exon swap and mutagenesis assays, we show exonic sequences can determine RS-exon inclusion. Finally, we provide evidence that splicing can suppress utilization of RP SDs to enable RS-exon expression. Overall, multiple factors can influence splicing of Drosophila RS-exons, which usually result in their complete suppression as zero-nucleotide RPs, but occasionally yield translated RS-exons.
Collapse
Affiliation(s)
- Brian Joseph
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA .,Louis V Gerstner, Jr Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Chaz Scala
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Shu Kondo
- Research Building 11F, Tokyo University of Science, Tokyo, Japan
| | - Eric C Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| |
Collapse
|
33
|
The upstream 5' splice site remains associated to the transcription machinery during intron synthesis. Nat Commun 2021; 12:4545. [PMID: 34315864 PMCID: PMC8316553 DOI: 10.1038/s41467-021-24774-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 07/02/2021] [Indexed: 12/28/2022] Open
Abstract
In the earliest step of spliceosome assembly, the two splice sites flanking an intron are brought into proximity by U1 snRNP and U2AF along with other proteins. The mechanism that facilitates this intron looping is poorly understood. Using a CRISPR interference-based approach to halt RNA polymerase II transcription in the middle of introns in human cells, we discovered that the nascent 5′ splice site base pairs with a U1 snRNA that is tethered to RNA polymerase II during intron synthesis. This association functionally corresponds with splicing outcome, involves bona fide 5′ splice sites and cryptic intronic sites, and occurs transcriptome-wide. Overall, our findings reveal that the upstream 5′ splice sites remain attached to the transcriptional machinery during intron synthesis and are thus brought into proximity of the 3′ splice sites; potentially mediating the rapid splicing of long introns. We know that most splicing reactions take place co-transcriptionally, but how the transcription machinery facilitate splicing of introns is unknown. Here the authors show that the 5′ splice site remains associated with the transcription machinery during intron synthesis through U1 snRNP, providing a basis for the rapid splicing reaction of introns.
Collapse
|
34
|
Otani Y, Fujita KI, Kameyama T, Mayeda A. The Exon Junction Complex Core Represses Cancer-Specific Mature mRNA Re-splicing: A Potential Key Role in Terminating Splicing. Int J Mol Sci 2021; 22:ijms22126519. [PMID: 34204574 PMCID: PMC8234774 DOI: 10.3390/ijms22126519] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/08/2021] [Indexed: 02/08/2023] Open
Abstract
Using TSG101 pre-mRNA, we previously discovered cancer-specific re-splicing of mature mRNA that generates aberrant transcripts/proteins. The fact that mRNA is aberrantly re-spliced in various cancer cells implies there must be an important mechanism to prevent deleterious re-splicing on the spliced mRNA in normal cells. We thus postulated that mRNA re-splicing is controlled by specific repressors, and we searched for repressor candidates by siRNA-based screening for mRNA re-splicing activity. We found that knock-down of EIF4A3, which is a core component of the exon junction complex (EJC), significantly promoted mRNA re-splicing. Remarkably, we could recapitulate cancer-specific mRNA re-splicing in normal cells by knock-down of any of the core EJC proteins, EIF4A3, MAGOH, or RBM8A (Y14), implicating the EJC core as the repressor of mRNA re-splicing often observed in cancer cells. We propose that the EJC core is a critical mRNA quality control factor to prevent over-splicing of mature mRNA.
Collapse
Affiliation(s)
- Yuta Otani
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan; (Y.O.); (K.-i.F.)
- Laboratories of Discovery Research, Nippon Shinyaku Co., Ltd., Kyoto 601-8550, Kyoto, Japan
| | - Ken-ichi Fujita
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan; (Y.O.); (K.-i.F.)
| | - Toshiki Kameyama
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan; (Y.O.); (K.-i.F.)
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake 470-1192, Aichi, Japan
- Correspondence: (T.K.); (A.M.)
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan; (Y.O.); (K.-i.F.)
- Correspondence: (T.K.); (A.M.)
| |
Collapse
|
35
|
Wilkins OG, Capitanchik C, Luscombe NM, Ule J. Ultraplex: A rapid, flexible, all-in-one fastq demultiplexer. Wellcome Open Res 2021; 6:141. [PMID: 34286104 PMCID: PMC8287537 DOI: 10.12688/wellcomeopenres.16791.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2021] [Indexed: 01/23/2023] Open
Abstract
Background: The first step of virtually all next generation sequencing analysis involves the splitting of the raw sequencing data into separate files using sample-specific barcodes, a process known as "demultiplexing". However, we found that existing software for this purpose was either too inflexible or too computationally intensive for fast, streamlined processing of raw, single end fastq files containing combinatorial barcodes. Results: Here, we introduce a fast and uniquely flexible demultiplexer, named Ultraplex, which splits a raw FASTQ file containing barcodes either at a single end or at both 5' and 3' ends of reads, trims the sequencing adaptors and low-quality bases, and moves unique molecular identifiers (UMIs) into the read header, allowing subsequent removal of PCR duplicates. Ultraplex is able to perform such single or combinatorial demultiplexing on both single- and paired-end sequencing data, and can process an entire Illumina HiSeq lane, consisting of nearly 500 million reads, in less than 20 minutes. Conclusions: Ultraplex greatly reduces computational burden and pipeline complexity for the demultiplexing of complex sequencing libraries, such as those produced by various CLIP and ribosome profiling protocols, and is also very user friendly, enabling streamlined, robust data processing. Ultraplex is available on PyPi and Conda and via Github.
Collapse
Affiliation(s)
- Oscar G Wilkins
- The Francis Crick Institute, London, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | | | - Nicholas M. Luscombe
- The Francis Crick Institute, London, UK
- UCL Genetics Institute, Department of Genetics, Environment and Evolution, University College London, London, UK
- Okinawa Institute of Science & Technology Graduate University, Okinawa, Japan
| | - Jernej Ule
- The Francis Crick Institute, London, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| |
Collapse
|
36
|
Simone R, Javad F, Emmett W, Wilkins OG, Almeida FL, Barahona-Torres N, Zareba-Paslawska J, Ehteramyan M, Zuccotti P, Modelska A, Siva K, Virdi GS, Mitchell JS, Harley J, Kay VA, Hondhamuni G, Trabzuni D, Ryten M, Wray S, Preza E, Kia DA, Pittman A, Ferrari R, Manzoni C, Lees A, Hardy JA, Denti MA, Quattrone A, Patani R, Svenningsson P, Warner TT, Plagnol V, Ule J, de Silva R. MIR-NATs repress MAPT translation and aid proteostasis in neurodegeneration. Nature 2021; 594:117-123. [PMID: 34012113 PMCID: PMC7610982 DOI: 10.1038/s41586-021-03556-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 04/15/2021] [Indexed: 12/22/2022]
Abstract
The human genome expresses thousands of natural antisense transcripts (NAT) that can regulate epigenetic state, transcription, RNA stability or translation of their overlapping genes1,2. Here we describe MAPT-AS1, a brain-enriched NAT that is conserved in primates and contains an embedded mammalian-wide interspersed repeat (MIR), which represses tau translation by competing for ribosomal RNA pairing with the MAPT mRNA internal ribosome entry site3. MAPT encodes tau, a neuronal intrinsically disordered protein (IDP) that stabilizes axonal microtubules. Hyperphosphorylated, aggregation-prone tau forms the hallmark inclusions of tauopathies4. Mutations in MAPT cause familial frontotemporal dementia, and common variations forming the MAPT H1 haplotype are a significant risk factor in many tauopathies5 and Parkinson's disease. Notably, expression of MAPT-AS1 or minimal essential sequences from MAPT-AS1 (including MIR) reduces-whereas silencing MAPT-AS1 expression increases-neuronal tau levels, and correlate with tau pathology in human brain. Moreover, we identified many additional NATs with embedded MIRs (MIR-NATs), which are overrepresented at coding genes linked to neurodegeneration and/or encoding IDPs, and confirmed MIR-NAT-mediated translational control of one such gene, PLCG1. These results demonstrate a key role for MAPT-AS1 in tauopathies and reveal a potentially broad contribution of MIR-NATs to the tightly controlled translation of IDPs6, with particular relevance for proteostasis in neurodegeneration.
Collapse
Affiliation(s)
- Roberto Simone
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK.
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.
| | - Faiza Javad
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Warren Emmett
- UCL Genetics Institute, London, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- Inivata Ltd, Babraham, UK
| | - Oscar G Wilkins
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Filipa Lourenço Almeida
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Natalia Barahona-Torres
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | | | - Mazdak Ehteramyan
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Paola Zuccotti
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, Italy
| | - Angelika Modelska
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, Italy
| | - Kavitha Siva
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, Italy
| | - Gurvir S Virdi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Jamie S Mitchell
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Jasmine Harley
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Victoria A Kay
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Geshanthi Hondhamuni
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Daniah Trabzuni
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Mina Ryten
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Selina Wray
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Elisavet Preza
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Demis A Kia
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Alan Pittman
- Genetics Research Centre, Molecular and Clinical Sciences, St George's University of London, London, UK
| | - Raffaele Ferrari
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Claudia Manzoni
- UCL School of Pharmacy, Department of Pharmacology, London, UK
| | - Andrew Lees
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - John A Hardy
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- UK Dementia Research Institute, UCL, London, UK
- Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, SAR, China
| | - Michela A Denti
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, Italy
| | - Alessandro Quattrone
- Department of Cellular, Computational and Integrative Biology (CIBIO), Trento, Italy
| | - Rickie Patani
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Per Svenningsson
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Thomas T Warner
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | | | - Jernej Ule
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Rohan de Silva
- Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, London, UK.
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.
| |
Collapse
|
37
|
Joseph B, Lai EC. The Exon Junction Complex and intron removal prevent re-splicing of mRNA. PLoS Genet 2021; 17:e1009563. [PMID: 34033644 PMCID: PMC8184009 DOI: 10.1371/journal.pgen.1009563] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 06/07/2021] [Accepted: 04/26/2021] [Indexed: 01/23/2023] Open
Abstract
Accurate splice site selection is critical for fruitful gene expression. Recently, the mammalian EJC was shown to repress competing, cryptic, splice sites (SS). However, the evolutionary generality of this remains unclear. Here, we demonstrate the Drosophila EJC suppresses hundreds of functional cryptic SS, even though most bear weak splicing motifs and are seemingly incompetent. Mechanistically, the EJC directly conceals cryptic splicing elements by virtue of its position-specific recruitment, preventing aberrant SS definition. Unexpectedly, we discover the EJC inhibits scores of regenerated 5' and 3' recursive SS on segments that have already undergone splicing, and that loss of EJC regulation triggers faulty resplicing of mRNA. An important corollary is that certain intronless cDNA constructs yield unanticipated, truncated transcripts generated by resplicing. We conclude the EJC has conserved roles to defend transcriptome fidelity by (1) repressing illegitimate splice sites on pre-mRNAs, and (2) preventing inadvertent activation of such sites on spliced segments.
Collapse
Affiliation(s)
- Brian Joseph
- Developmental Biology Program, Sloan Kettering Institute, New York, New York, United States of America
- Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Eric C. Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, New York, United States of America
- Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| |
Collapse
|
38
|
Conboy JG. Unannotated splicing regulatory elements in deep intron space. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1656. [PMID: 33887804 DOI: 10.1002/wrna.1656] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/14/2021] [Accepted: 03/23/2021] [Indexed: 12/21/2022]
Abstract
Deep intron space harbors a diverse array of splicing regulatory elements that cooperate with better-known exon-proximal elements to enforce proper tissue-specific and development-specific pre-mRNA processing. Many deep intron elements have been highly conserved through vertebrate evolution, yet remain poorly annotated in the human genome. Recursive splicing exons (RS-exons) and intraexons promote noncanonical, multistep resplicing pathways in long introns, involving transient intermediate structures that are greatly underrepresented in RNA-seq datasets. Decoy splice sites and decoy exons act at a distance to inhibit splicing catalysis at annotated splice sites, with functional consequences such as exon skipping and intron retention. RNA:RNA bridges can juxtapose distant sequences within or across introns to activate deep intron splicing enhancers and silencers, to loop out exons to be skipped, or to select one member of a mutually exclusive set of exons. Similarly, protein bridges mediated by interactions among transcript-bound RNA binding proteins (RBPs) can modulate splicing outcomes. Experimental disruption of deep intron elements serving any of these functions can abrogate normal splicing, strongly suggesting that natural mutations of deep intron elements can do likewise to cause human disease. Understanding noncanonical splicing pathways and discovering deep intron regulatory signals, many of which map hundreds to many thousands of nucleotides from annotated splice junctions, is of great academic interest for basic scientists studying alternative splicing mechanisms. Hopefully, this knowledge coupled with increased analysis of deep intron sequences will also have important medical applications, as better interpretation of deep intron mutations may reveal new disease mechanisms and suggest new therapies. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing.
Collapse
Affiliation(s)
- John G Conboy
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, California, USA
| |
Collapse
|
39
|
Gehring NH, Roignant JY. Anything but Ordinary – Emerging Splicing Mechanisms in Eukaryotic Gene Regulation. Trends Genet 2021; 37:355-372. [DOI: 10.1016/j.tig.2020.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022]
|
40
|
Gordon PM, Hamid F, Makeyev EV, Houart C. A conserved role for the ALS-linked splicing factor SFPQ in repression of pathogenic cryptic last exons. Nat Commun 2021; 12:1918. [PMID: 33771997 PMCID: PMC7997972 DOI: 10.1038/s41467-021-22098-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 02/24/2021] [Indexed: 12/13/2022] Open
Abstract
The RNA-binding protein SFPQ plays an important role in neuronal development and has been associated with several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Alzheimer's disease. Here, we report that loss of sfpq leads to premature termination of multiple transcripts due to widespread activation of previously unannotated cryptic last exons (CLEs). These SFPQ-inhibited CLEs appear preferentially in long introns of genes with neuronal functions and can dampen gene expression outputs and/or give rise to short peptides interfering with the normal gene functions. We show that one such peptide encoded by the CLE-containing epha4b mRNA isoform is responsible for neurodevelopmental defects in the sfpq mutant. The uncovered CLE-repressive activity of SFPQ is conserved in mouse and human, and SFPQ-inhibited CLEs are found expressed across ALS iPSC-derived neurons. These results greatly expand our understanding of SFPQ function and uncover a gene regulation mechanism with wide relevance to human neuropathologies.
Collapse
Affiliation(s)
- Patricia M Gordon
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, IoPPN, Guy's Campus, King's College London, London, SE1 1UL, UK.
| | - Fursham Hamid
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, IoPPN, Guy's Campus, King's College London, London, SE1 1UL, UK
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, IoPPN, Guy's Campus, King's College London, London, SE1 1UL, UK
| | - Corinne Houart
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, IoPPN, Guy's Campus, King's College London, London, SE1 1UL, UK.
| |
Collapse
|
41
|
Hafner M, Katsantoni M, Köster T, Marks J, Mukherjee J, Staiger D, Ule J, Zavolan M. CLIP and complementary methods. ACTA ACUST UNITED AC 2021. [DOI: 10.1038/s43586-021-00018-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
42
|
Thrown for a (stem) loop: How RNA structure impacts circular RNA regulation and function. Methods 2021; 196:56-67. [PMID: 33662561 DOI: 10.1016/j.ymeth.2021.02.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/09/2021] [Accepted: 02/26/2021] [Indexed: 12/26/2022] Open
Abstract
Exonic circular RNAs (circRNAs) are RNA molecules that are covalently closed by back-splicing via canonical splicing machinery. Despite overlapping sequences, exon circularization generates RNA secondary structures through intramolecular base-pairing that are different from the linear transcript. Here we review factors that may affect circRNA structure and how structure affects circRNA function and regulation. We highlight considerations for RNA sequencing and expression measurement to ensure highly structured circRNAs are accurately represented by the data and discuss issues that need to be addressed in generating circRNAs to recapitulate their endogenous structures. We conclude our review by discussing experimental strategies on revealing the varied roles of RNA structure in circRNA biogenesis, function and decay.
Collapse
|
43
|
Pathways of calcium regulation, electron transport, and mitochondrial protein translation are molecular signatures of susceptibility to recurrent exertional rhabdomyolysis in Thoroughbred racehorses. PLoS One 2021; 16:e0244556. [PMID: 33566847 PMCID: PMC7875397 DOI: 10.1371/journal.pone.0244556] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/13/2020] [Indexed: 12/13/2022] Open
Abstract
Recurrent exertional rhabdomyolysis (RER) is a chronic muscle disorder of unknown etiology in racehorses. A potential role of intramuscular calcium (Ca2+) dysregulation in RER has led to the use of dantrolene to prevent episodes of rhabdomyolysis. We examined differentially expressed proteins (DEP) and gene transcripts (DEG) in gluteal muscle of Thoroughbred race-trained mares after exercise among three groups of 5 horses each; 1) horses susceptible to, but not currently experiencing rhabdomyolysis, 2) healthy horses with no history of RER (control), 3) RER-susceptible horses treated with dantrolene pre-exercise (RER-D). Tandem mass tag LC/MS/MS quantitative proteomics and RNA-seq analysis (FDR <0.05) was followed by gene ontology (GO) and semantic similarity of enrichment terms. Of the 375 proteins expressed, 125 were DEP in RER-susceptible versus control, with 52 ↑DEP mainly involving Ca2+ regulation (N = 11) (e.g. RYR1, calmodulin, calsequestrin, calpain), protein degradation (N = 6), antioxidants (N = 4), plasma membranes (N = 3), glyco(geno)lysis (N = 3) and 21 DEP being blood-borne. ↓DEP (N = 73) were largely mitochondrial (N = 45) impacting the electron transport system (28), enzymes (6), heat shock proteins (4), and contractile proteins (12) including Ca2+ binding proteins. There were 812 DEG in RER-susceptible versus control involving the electron transfer system, the mitochondrial transcription/translational response and notably the pro-apoptotic Ca2+-activated mitochondrial membrane transition pore (SLC25A27, BAX, ATP5 subunits). Upregulated mitochondrial DEG frequently had downregulation of their encoded DEP with semantic similarities highlighting signaling mechanisms regulating mitochondrial protein translation. RER-susceptible horses treated with dantrolene, which slows sarcoplasmic reticulum Ca2+ release, showed no DEG compared to control horses. We conclude that RER-susceptibility is associated with alterations in proteins, genes and pathways impacting myoplasmic Ca2+ regulation, the mitochondrion and protein degradation with opposing effects on mitochondrial transcriptional/translational responses and mitochondrial protein content. RER could potentially arise from excessive sarcoplasmic reticulum Ca2+ release and subsequent mitochondrial buffering of excessive myoplasmic Ca2+.
Collapse
|
44
|
Zhou Y, Li Z, Wu X, Tou L, Zheng J, Zhou D. MAGOH/MAGOHB Inhibits the Tumorigenesis of Gastric Cancer via Inactivation of b-RAF/MEK/ERK Signaling. Onco Targets Ther 2020; 13:12723-12735. [PMID: 33328743 PMCID: PMC7735944 DOI: 10.2147/ott.s263913] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/22/2020] [Indexed: 12/20/2022] Open
Abstract
Background Gastric cancer is one of the most malignant tumors all over the world. It has been reported that proteins play key roles during the tumorigenesis of gastric cancer. To identify novel potential targets for gastric cancer, differential expressed proteins between gastric cancer and adjacent normal tissues were analyzed with proteomics and bioinformatics tool. Methods The differentially expressed proteins between gastric cancer and adjacent normal tissues were analyzed by Omicsbean (multi-omics data analysis tool). Cell viability was tested by CCK-8 assay. Flow cytometry was used to measure cell apoptosis and cycle. Transwell assay was used to test cell migration and invasion. Gene and protein expressions were detected by RT-qPCR, immunohistochemistry and Western blot, respectively. Results MAGOH and MAGOHB were found to be notably upregulated in gastric cancer tissues compared with that in normal tissues. Knockdown of MAGOH significantly inhibited the proliferation of gastric cancer cells via inducing the cell apoptosis. In addition, MAGOH knockdown induced G2 phase arrest in gastric cancer cells. Moreover, MAGOH knockdown notably inhibited migration and invasion of gastric cancer cells. Importantly, double knockdown of MAGOH and MAGOHB exhibited much better anti-tumor effects on gastric cancer compared with alone treatment. Finally, double knockdown of MAGOH and MAGOHB mediated the tumorigenesis of gastric cancer via regulation of RAF/MEK/ERK signaling. Conclusion MAGOH knockdown inhibited the tumorigenesis of gastric cancer via mediation of b-RAF/MEK/ERK signaling, and double knockdown of MAGOH and MAGOHB exhibited much better anti-tumor effects. This finding might provide us a new strategy for the treatment of gastric cancer.
Collapse
Affiliation(s)
- Yong Zhou
- Department of Oncology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, People's Republic of China
| | - Zhongqi Li
- Department of Oncology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, People's Republic of China
| | - Xuan Wu
- Department of Oncology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, People's Republic of China
| | - Laizhen Tou
- Department of Oncology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, People's Republic of China
| | - Jingjing Zheng
- Department of General Surgery, Lishui Municipal Central Hospital, Lishui, Zhejiang 323000, People's Republic of China
| | - Donghui Zhou
- Department of Oncology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, People's Republic of China
| |
Collapse
|
45
|
Li M. Calculating the most likely intron splicing orders in S. pombe, fruit fly, Arabidopsis thaliana, and humans. BMC Bioinformatics 2020; 21:478. [PMID: 33099301 PMCID: PMC7585206 DOI: 10.1186/s12859-020-03818-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 10/15/2020] [Indexed: 12/01/2022] Open
Abstract
Background Introns have been shown to be spliced in a defined order, and this order influences both alternative splicing regulation and splicing fidelity, but previous studies have only considered neighbouring introns. The detailed intron splicing order remains unknown.
Results In this work, a method was developed that can calculate the intron splicing orders of all introns in each transcript. A simulation study showed that this method can accurately calculate intron splicing orders. I further applied this method to real S. pombe, fruit fly, Arabidopsis thaliana, and human sequencing datasets and found that intron splicing orders change from gene to gene and that humans contain more not in-order spliced transcripts than S. pombe, fruit fly and Arabidopsis thaliana. In addition, I reconfirmed that the first introns in humans are spliced slower than those in S. pombe, fruit fly, and Arabidopsis thaliana genome-widely. Both the calculated most likely orders and the method developed here are available on the web. Conclusions A novel computational method was developed to calculate the intron splicing orders and applied the method to real sequencing datasets. I obtained intron splicing orders for hundreds or thousands of genes in four organisms. I found humans contain more number of not in-order spliced transcripts.
Collapse
|
46
|
Gerbracht JV, Boehm V, Britto-Borges T, Kallabis S, Wiederstein JL, Ciriello S, Aschemeier DU, Krüger M, Frese CK, Altmüller J, Dieterich C, Gehring NH. CASC3 promotes transcriptome-wide activation of nonsense-mediated decay by the exon junction complex. Nucleic Acids Res 2020; 48:8626-8644. [PMID: 32621609 PMCID: PMC7470949 DOI: 10.1093/nar/gkaa564] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/20/2020] [Accepted: 07/01/2020] [Indexed: 01/08/2023] Open
Abstract
The exon junction complex (EJC) is an essential constituent and regulator of spliced messenger ribonucleoprotein particles (mRNPs) in metazoans. As a core component of the EJC, CASC3 was described to be pivotal for EJC-dependent nuclear and cytoplasmic processes. However, recent evidence suggests that CASC3 functions differently from other EJC core proteins. Here, we have established human CASC3 knockout cell lines to elucidate the cellular role of CASC3. In the knockout cells, overall EJC composition and EJC-dependent splicing are unchanged. A transcriptome-wide analysis reveals that hundreds of mRNA isoforms targeted by nonsense-mediated decay (NMD) are upregulated. Mechanistically, recruiting CASC3 to reporter mRNAs by direct tethering or via binding to the EJC stimulates mRNA decay and endonucleolytic cleavage at the termination codon. Building on existing EJC-NMD models, we propose that CASC3 equips the EJC with the persisting ability to communicate with the NMD machinery in the cytoplasm. Collectively, our results characterize CASC3 as a peripheral EJC protein that tailors the transcriptome by promoting the degradation of EJC-dependent NMD substrates.
Collapse
Affiliation(s)
| | - Volker Boehm
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Thiago Britto-Borges
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, University of Heidelberg, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Sebastian Kallabis
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janica L Wiederstein
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Simona Ciriello
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | | | - Marcus Krüger
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Christian K Frese
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, University of Heidelberg, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| |
Collapse
|
47
|
Patton RD, Sanjeev M, Woodward LA, Mabin JW, Bundschuh R, Singh G. Chemical crosslinking enhances RNA immunoprecipitation for efficient identification of binding sites of proteins that photo-crosslink poorly with RNA. RNA (NEW YORK, N.Y.) 2020; 26:1216-1233. [PMID: 32467309 PMCID: PMC7430673 DOI: 10.1261/rna.074856.120] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 05/17/2020] [Indexed: 05/14/2023]
Abstract
In eukaryotic cells, proteins that associate with RNA regulate its activity to control cellular function. To fully illuminate the basis of RNA function, it is essential to identify such RNA-associated proteins, their mode of action on RNA, and their preferred RNA targets and binding sites. By analyzing catalogs of human RNA-associated proteins defined by ultraviolet light (UV)-dependent and -independent approaches, we classify these proteins into two major groups: (i) the widely recognized RNA binding proteins (RBPs), which bind RNA directly and UV-crosslink efficiently to RNA, and (ii) a new group of RBP-associated factors (RAFs), which bind RNA indirectly via RBPs and UV-crosslink poorly to RNA. As the UV crosslinking and immunoprecipitation followed by sequencing (CLIP-seq) approach will be unsuitable to identify binding sites of RAFs, we show that formaldehyde crosslinking stabilizes RAFs within ribonucleoproteins to allow for their immunoprecipitation under stringent conditions. Using an RBP (CASC3) and an RAF (RNPS1) within the exon junction complex (EJC) as examples, we show that formaldehyde crosslinking combined with RNA immunoprecipitation in tandem followed by sequencing (xRIPiT-seq) far exceeds CLIP-seq to identify binding sites of RNPS1. xRIPiT-seq reveals that RNPS1 occupancy is increased on exons immediately upstream of strong recursively spliced exons, which depend on the EJC for their inclusion.
Collapse
Affiliation(s)
- Robert D Patton
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Manu Sanjeev
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Lauren A Woodward
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Justin W Mabin
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ralf Bundschuh
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
| | - Guramrit Singh
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| |
Collapse
|
48
|
Obrdlik A, Lin G, Haberman N, Ule J, Ephrussi A. The Transcriptome-wide Landscape and Modalities of EJC Binding in Adult Drosophila. Cell Rep 2020; 28:1219-1236.e11. [PMID: 31365866 DOI: 10.1016/j.celrep.2019.06.088] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 04/30/2019] [Accepted: 06/24/2019] [Indexed: 12/27/2022] Open
Abstract
Exon junction complex (EJC) assembles after splicing at specific positions upstream of exon-exon junctions in mRNAs of all higher eukaryotes, affecting major regulatory events. In mammalian cell cytoplasm, EJC is essential for efficient RNA surveillance, while in Drosophila, EJC is essential for localization of oskar mRNA. Here we developed a method for isolation of protein complexes and associated RNA targets (ipaRt) to explore the EJC RNA-binding landscape in a transcriptome-wide manner in adult Drosophila. We find the EJC at canonical positions, preferably on mRNAs from genes comprising multiple splice sites and long introns. Moreover, EJC occupancy is highest at junctions adjacent to strong splice sites, CG-rich hexamers, and RNA structures. Highly occupied mRNAs tend to be maternally localized and derive from genes involved in differentiation or development. These modalities, which have not been reported in mammals, specify EJC assembly on a biologically coherent set of transcripts in Drosophila.
Collapse
Affiliation(s)
- Ales Obrdlik
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | - Gen Lin
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Nejc Haberman
- Department for Neuromuscular Diseases, UCL Institute of Neurology, London WC1N 3BG, UK
| | - Jernej Ule
- Department for Neuromuscular Diseases, UCL Institute of Neurology, London WC1N 3BG, UK; The Francis Crick Institute, London NW1 1AT, UK
| | - Anne Ephrussi
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| |
Collapse
|
49
|
Sepe RM, Ghiron JHL, Zucchetti I, Caputi L, Tarallo R, Crocetta F, De Santis R, D'Aniello S, Sordino P. The EJC component Magoh in non-vertebrate chordates. Dev Genes Evol 2020; 230:295-304. [PMID: 32632492 DOI: 10.1007/s00427-020-00664-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 07/01/2020] [Indexed: 11/26/2022]
Abstract
Earliest craniates possess a newly enlarged, elaborated forebrain with new cell types and neuronal networks. A key question in vertebrate evolution is when and how this cerebral expansion took place. The exon-junction complex (EJC) plays an essential role in mRNA processing of all Eukarya. Recently, it has been proposed that the EJC represses recursive RNA splicing in Deuterostomes, with implication in human brain diseases like microcephaly and depression. However, the EJC or EJC subunit contribution to brain development in non-vertebrate Deuterostomes remained unknown. Being interested in the evolution of chordate characters, we focused on the model species, Branchiostoma lanceolatum (Cephalochordata) and Ciona robusta (Tunicata), with the aim to investigate the ancestral and the derived expression state of Magoh orthologous genes. This study identifies that Magoh is part of a conserved syntenic group exclusively in vertebrates and suggests that Magoh has experienced duplication and loss events in mammals. During early development in amphioxus and ascidian, maternal contribution and zygotic expression of Magoh genes in various types of progenitor cells and tissues are consistent with the condition observed in other Bilateria. Later in development, we also show expression of Magoh in the brain of cephalochordate and ascidian larvae. Collectively, these results provide a basis to further define what functional role(s) Magoh exerted during nervous system development and evolution.
Collapse
Affiliation(s)
- Rosa Maria Sepe
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy
| | - Jung Hee Levialdi Ghiron
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy
| | - Ivana Zucchetti
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy
| | - Luigi Caputi
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy
| | - Raffaella Tarallo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy
| | - Fabio Crocetta
- Department of Integrated Marine Ecology, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy
| | - Rosaria De Santis
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy
| | - Salvatore D'Aniello
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy.
| | - Paolo Sordino
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn Napoli, 80121, Naples, Italy.
| |
Collapse
|
50
|
A Day in the Life of the Exon Junction Complex. Biomolecules 2020; 10:biom10060866. [PMID: 32517083 PMCID: PMC7355637 DOI: 10.3390/biom10060866] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 12/12/2022] Open
Abstract
The exon junction complex (EJC) is an abundant messenger ribonucleoprotein (mRNP) component that is assembled during splicing and binds to mRNAs upstream of exon-exon junctions. EJCs accompany the mRNA during its entire life in the nucleus and the cytoplasm and communicate the information about the splicing process and the position of introns. Specifically, the EJC’s core components and its associated proteins regulate different steps of gene expression, including pre-mRNA splicing, mRNA export, translation, and nonsense-mediated mRNA decay (NMD). This review summarizes the most important functions and main protagonists in the life of the EJC. It also provides an overview of the latest findings on the assembly, composition and molecular activities of the EJC and presents them in the chronological order, in which they play a role in the EJC’s life cycle.
Collapse
|