1
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Li Y, He P, Zheng L, Zhou X. Histone-modifying enzymes: Roles in odontogenesis and beyond. Oral Dis 2024. [PMID: 38376106 DOI: 10.1111/odi.14894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 01/25/2024] [Accepted: 01/31/2024] [Indexed: 02/21/2024]
Abstract
OBJECTIVES Odontogenesis, an intricate process initiated by epithelium-mesenchyme interaction, is meticulously regulated by a cascade of regulatory mechanisms. Epigenetic modifications, especially histone modification, have been found to exhibit spatiotemporal specificity during tooth development. However, the expression patterns and roles of enzymes associated with histone modifications have yet to be systematically explored in odontogenesis. This review aims to summarize the histone-modifying enzymes in odontogenesis and their regulation mechanism during tooth development and provide the potential theoretical basis for the clinical management and intervention of dental developmental diseases. SUBJECTS AND METHODS This study conducted a systematic search across PubMed and Web of Science databases, utilizing the keywords "odontogenesis," "histone modification," and "enzyme" for pertinent articles. RESULTS No doubt histone modification contributes extensively to odontogenesis regulation, and the disturbances in histone modifications can derange the odontogenesis process. CONCLUSION Further studies are warranted to elucidate these roles and their potential downstream effects, positioning histone modifications as a pivotal focal point for unraveling the intricacies of tooth development and regeneration.
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Affiliation(s)
- Yiting Li
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Pengcheng He
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Liwei Zheng
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xin Zhou
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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2
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Nagasawa CK, Garcia-Blanco MA. Early Splicing Complexes and Human Disease. Int J Mol Sci 2023; 24:11412. [PMID: 37511171 PMCID: PMC10379813 DOI: 10.3390/ijms241411412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
Over the last decade, our understanding of spliceosome structure and function has significantly improved, refining the study of the impact of dysregulated splicing on human disease. As a result, targeted splicing therapeutics have been developed, treating various diseases including spinal muscular atrophy and Duchenne muscular dystrophy. These advancements are very promising and emphasize the critical role of proper splicing in maintaining human health. Herein, we provide an overview of the current information on the composition and assembly of early splicing complexes-commitment complex and pre-spliceosome-and their association with human disease.
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Affiliation(s)
- Chloe K. Nagasawa
- Human Pathophysiology and Translational Medicine Program, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX 77555-5302, USA;
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22903-2628, USA
| | - Mariano A. Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22903-2628, USA
- Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555-5302, USA
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3
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Devoucoux M, Fort V, Khelifi G, Xu J, Alerasool N, Galloy M, Wong N, Bourriquen G, Fradet-Turcotte A, Taipale M, Hope K, Hussein SMI, Côté J. Oncogenic ZMYND11-MBTD1 fusion protein anchors the NuA4/TIP60 histone acetyltransferase complex to the coding region of active genes. Cell Rep 2022; 39:110947. [PMID: 35705031 DOI: 10.1016/j.celrep.2022.110947] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 02/14/2022] [Accepted: 05/23/2022] [Indexed: 11/26/2022] Open
Abstract
A recurrent chromosomal translocation found in acute myeloid leukemia leads to an in-frame fusion of the transcription repressor ZMYND11 to MBTD1, a subunit of the NuA4/TIP60 histone acetyltransferase complex. To understand the abnormal molecular events that ZMYND11-MBTD1 expression can create, we perform a biochemical and functional characterization comparison to each individual fusion partner. ZMYND11-MBTD1 is stably incorporated into the endogenous NuA4/TIP60 complex, leading to its mislocalization on the body of genes normally bound by ZMYND11. This can be correlated to increased chromatin acetylation and altered gene transcription, most notably on the MYC oncogene, and alternative splicing. Importantly, ZMYND11-MBTD1 expression favors Myc-driven pluripotency during embryonic stem cell differentiation and self-renewal of hematopoietic stem/progenitor cells. Altogether, these results indicate that the ZMYND11-MBTD1 fusion functions primarily by mistargeting the NuA4/TIP60 complex to the body of genes, altering normal transcription of specific genes, likely driving oncogenesis in part through the Myc regulatory network.
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Affiliation(s)
- Maëva Devoucoux
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada
| | - Victoire Fort
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada
| | - Gabriel Khelifi
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada
| | - Joshua Xu
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada; Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Nader Alerasool
- Donnelly Centre for Cellular and Biomolecular Research, Department of Molecular Genetics, University of Toronto, Toronto ON, Canada
| | - Maxime Galloy
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada
| | - Nicholas Wong
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Gaëlle Bourriquen
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada
| | - Amelie Fradet-Turcotte
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada
| | - Mikko Taipale
- Donnelly Centre for Cellular and Biomolecular Research, Department of Molecular Genetics, University of Toronto, Toronto ON, Canada
| | - Kristin Hope
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Samer M I Hussein
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada.
| | - Jacques Côté
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of CHU de Québec-Université Laval Research Center, Quebec City, QC G1R 3S3, Canada.
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4
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Akhlaghpour H. An RNA-Based Theory of Natural Universal Computation. J Theor Biol 2021; 537:110984. [PMID: 34979104 DOI: 10.1016/j.jtbi.2021.110984] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 09/30/2021] [Accepted: 12/07/2021] [Indexed: 12/15/2022]
Abstract
Life is confronted with computation problems in a variety of domains including animal behavior, single-cell behavior, and embryonic development. Yet we currently do not know of a naturally existing biological system that is capable of universal computation, i.e., Turing-equivalent in scope. Generic finite-dimensional dynamical systems (which encompass most models of neural networks, intracellular signaling cascades, and gene regulatory networks) fall short of universal computation, but are assumed to be capable of explaining cognition and development. I present a class of models that bridge two concepts from distant fields: combinatory logic (or, equivalently, lambda calculus) and RNA molecular biology. A set of basic RNA editing rules can make it possible to compute any computable function with identical algorithmic complexity to that of Turing machines. The models do not assume extraordinarily complex molecular machinery or any processes that radically differ from what we already know to occur in cells. Distinct independent enzymes can mediate each of the rules and RNA molecules solve the problem of parenthesis matching through their secondary structure. In the most plausible of these models all of the editing rules can be implemented with merely cleavage and ligation operations at fixed positions relative to predefined motifs. This demonstrates that universal computation is well within the reach of molecular biology. It is therefore reasonable to assume that life has evolved - or possibly began with - a universal computer that yet remains to be discovered. The variety of seemingly unrelated computational problems across many scales can potentially be solved using the same RNA-based computation system. Experimental validation of this theory may immensely impact our understanding of memory, cognition, development, disease, evolution, and the early stages of life.
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Affiliation(s)
- Hessameddin Akhlaghpour
- Laboratory of Integrative Brain Function, The Rockefeller University, New York, NY, 10065, USA
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5
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Baker M, Petasny M, Taqatqa N, Bentata M, Kay G, Engal E, Nevo Y, Siam A, Dahan S, Salton M. KDM3A regulates alternative splicing of cell-cycle genes following DNA damage. RNA (NEW YORK, N.Y.) 2021; 27:1353-1362. [PMID: 34321328 PMCID: PMC8522690 DOI: 10.1261/rna.078796.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Changes in the cellular environment result in chromatin structure alteration, which in turn regulates gene expression. To learn about the effect of the cellular environment on the transcriptome, we studied the H3K9 demethylase KDM3A. Using RNA-seq, we found that KDM3A regulates the transcription and alternative splicing of genes associated with cell cycle and DNA damage. We showed that KDM3A undergoes phosphorylation by PKA at serine 265 following DNA damage, and that the phosphorylation is important for proper cell-cycle regulation. We demonstrated that SAT1 alternative splicing, regulated by KDM3A, plays a role in cell-cycle regulation. Furthermore we found that KDM3A's demethylase activity is not needed for SAT1 alternative splicing regulation. In addition, we identified KDM3A's protein partner ARID1A, the SWI/SNF subunit, and SRSF3 as regulators of SAT1 alternative splicing and showed that KDM3A is essential for SRSF3 binding to SAT1 pre-mRNA. These results suggest that KDM3A serves as a sensor of the environment and an adaptor for splicing factor binding. Our work reveals chromatin sensing of the environment in the regulation of alternative splicing.
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Affiliation(s)
- Mai Baker
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mayra Petasny
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Nadeen Taqatqa
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mercedes Bentata
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Gillian Kay
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Eden Engal
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Yuval Nevo
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Ahmad Siam
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Sara Dahan
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Maayan Salton
- Department of Biochemistry and Molecular Biology, the Institute for Medical Research Israel Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
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6
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Hou C, Zhou L, Yang M, Jiang S, Shen H, Zhu M, Chen J, Miao M, Xu Y, Wu D. The Prognostic Value of Early Detection of Minimal Residual Disease as Defined by Flow Cytometry and Gene Mutation Clearance for Myelodysplastic Syndrome Patients After Myeloablative Allogeneic Hematopoietic Stem-Cell Transplantation. Front Oncol 2021; 11:700234. [PMID: 34422653 PMCID: PMC8374104 DOI: 10.3389/fonc.2021.700234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 06/14/2021] [Indexed: 01/17/2023] Open
Abstract
High relapse incidence remains a major problem for myelodysplastic syndrome (MDS) patients who have received an allogeneic hematopoietic stem-cell transplantation (allo-HSCT). We retrospectively analyzed the correlations between clinical outcomes and minimal residual disease (MRD) by using mutations (MUT) and flow cytometry (FCM) analysis of 115 MDS patients with allo-HSCT. We divided 115 MDS patients into four groups based on molecular genetics and FCM MRD results at day 30 post-HSCT. There were significant differences in the 2-year progression-free survival (PFS) between the FCMhigh MUTpos and FCMlow MUTneg groups (20% vs 79%, P < 0.001). In addition, by univariate analysis, we found that an IPSS-R score ≥4 pre-HSCT (HR, 5.061; P=0.007), DNMT3A mutations (HR, 2.291; P=0.052), TP53 mutations (HR, 3.946; P=0.011), and poor and very poor revised International Prognostic Scoring System (IPSS-R) cytogenetic risk (HR, 4.906; P < 0.001) were poor risk factors for PFS. In multivariate analysis, we found that an IPSS-R score ≥ 4 pre-HSCT (HR, 4.488; P=0.015), DNMT3A mutations (HR, 2.385; P=0.049), positive FCM MRD combined with persistence gene mutations at day 30 (HR, 5.198; P=0.013) were independent risk factors for disease progression. In conclusion, our data indicated that monitoring MRD by FCM combined with gene mutation clearance at day 30 could help in the prediction of disease progression for MDS patients after transplantation.
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Affiliation(s)
- Chang Hou
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Blood and Marrow Transplantation, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Lili Zhou
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Menglu Yang
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Shuhui Jiang
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hongjie Shen
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Mingqing Zhu
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jia Chen
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Miao Miao
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yang Xu
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Blood and Marrow Transplantation, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Depei Wu
- Jiangsu Institute of Hematology, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Blood and Marrow Transplantation, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
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7
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8
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Palazzo AF, Koonin EV. Functional Long Non-coding RNAs Evolve from Junk Transcripts. Cell 2020; 183:1151-1161. [PMID: 33068526 DOI: 10.1016/j.cell.2020.09.047] [Citation(s) in RCA: 128] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/20/2020] [Accepted: 09/17/2020] [Indexed: 12/30/2022]
Abstract
Transcriptome studies reveal pervasive transcription of complex genomes, such as those of mammals. Despite popular arguments for functionality of most, if not all, of these transcripts, genome-wide analysis of selective constraints indicates that most of the produced RNA are junk. However, junk is not garbage. On the contrary, junk transcripts provide the raw material for the evolution of diverse long non-coding (lnc) RNAs by non-adaptive mechanisms, such as constructive neutral evolution. The generation of many novel functional entities, such as lncRNAs, that fuels organismal complexity does not seem to be driven by strong positive selection. Rather, the weak selection regime that dominates the evolution of most multicellular eukaryotes provides ample material for functional innovation with relatively little adaptation involved.
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Affiliation(s)
- Alexander F Palazzo
- Department of Biochemistry, University of Toronto, Toronto, ON M5G 1M1, Canada.
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
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9
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Leung CS, Douglass SM, Morselli M, Obusan MB, Pavlyukov MS, Pellegrini M, Johnson TL. H3K36 Methylation and the Chromodomain Protein Eaf3 Are Required for Proper Cotranscriptional Spliceosome Assembly. Cell Rep 2020; 27:3760-3769.e4. [PMID: 31242410 PMCID: PMC6904931 DOI: 10.1016/j.celrep.2019.05.100] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/08/2019] [Accepted: 05/27/2019] [Indexed: 12/14/2022] Open
Abstract
In the eukaryotic cell, spliceosomes assemble onto pre-mRNA cotranscriptionally. Spliceosome assembly takes place in the context of the chromatin environment, suggesting that the state of the chromatin may affect splicing. The molecular details and mechanisms through which chromatin affects splicing, however, are still unclear. Here, we show a role for the histone methyltransferase Set2 and its histone modification, H3K36 methylation, in pre-mRNA splicing through high-throughput sequencing. Moreover, the effect of H3K36 methylation on pre-mRNA splicing is mediated through the chromodomain protein Eaf3. We find that Eaf3 is recruited to intron-containing genes and that Eaf3 interacts with the splicing factor Prp45. Eaf3 acts with Prp45 and Prp19 after formation of the precatalytic B complex around the time of splicing activation, thus revealing the step in splicing that is regulated by H3K36 methylation. These studies support a model whereby H3K36 facilitates recruitment of an "adapter protein" to support efficient, constitutive splicing.
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Affiliation(s)
- Calvin S Leung
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Stephen M Douglass
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Marco Morselli
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Matthew B Obusan
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Marat S Pavlyukov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russian Federation
| | - Matteo Pellegrini
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tracy L Johnson
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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10
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Canson D, Glubb D, Spurdle AB. Variant effect on splicing regulatory elements, branchpoint usage, and pseudoexonization: Strategies to enhance bioinformatic prediction using hereditary cancer genes as exemplars. Hum Mutat 2020; 41:1705-1721. [PMID: 32623769 DOI: 10.1002/humu.24074] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/15/2022]
Abstract
It is possible to estimate the prior probability of pathogenicity for germline disease gene variants based on bioinformatic prediction of variant effect/s. However, routinely used approaches have likely led to the underestimation and underreporting of variants located outside donor and acceptor splice site motifs that affect messenger RNA (mRNA) processing. This review presents information about hereditary cancer gene germline variants, outside native splice sites, with experimentally validated splicing effects. We list 95 exonic variants that impact splicing regulatory elements (SREs) in BRCA1, BRCA2, MLH1, MSH2, MSH6, and PMS2. We utilized a pre-existing large-scale BRCA1 functional data set to map functional SREs, and assess the relative performance of different tools to predict effects of 283 variants on such elements. We also describe rare examples of intronic variants that impact branchpoint (BP) sites and create pseudoexons. We discuss the challenges in predicting variant effect on BP site usage and pseudoexonization, and suggest strategies to improve the bioinformatic prioritization of such variants for experimental validation. Importantly, our review and analysis highlights the value of considering impact of variants outside donor and acceptor motifs on mRNA splicing and disease causation.
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Affiliation(s)
- Daffodil Canson
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Dylan Glubb
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Amanda B Spurdle
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
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11
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Mitra M, Lee HN, Coller HA. Splicing Busts a Move: Isoform Switching Regulates Migration. Trends Cell Biol 2020; 30:74-85. [PMID: 31810769 PMCID: PMC8219349 DOI: 10.1016/j.tcb.2019.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/21/2019] [Accepted: 10/25/2019] [Indexed: 11/21/2022]
Abstract
Cell migration is essential for normal development, neural patterning, pathogen eradication, and cancer metastasis. Pre-mRNA processing events such as alternative splicing and alternative polyadenylation result in greater transcript and protein diversity as well as function and activity. A critical role for alternative pre-mRNA processing in cell migration has emerged in axon outgrowth during neuronal development, immune cell migration, and cancer metastasis. These findings suggest that migratory signals result in expression changes of post-translational modifications of splicing or polyadenylation factors, leading to splicing events that generate promigratory isoforms. We summarize this recent progress and suggest emerging technologies that may facilitate a deeper understanding of the role of alternative splicing and polyadenylation in cell migration.
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Affiliation(s)
- Mithun Mitra
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, USA; Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Ha Neul Lee
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, USA; Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Hilary A Coller
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, USA; Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA; Bioinformatics Interdepartmental Program, University of California, Los Angeles, CA, USA.
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12
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Siam A, Baker M, Amit L, Regev G, Rabner A, Najar RA, Bentata M, Dahan S, Cohen K, Araten S, Nevo Y, Kay G, Mandel-Gutfreund Y, Salton M. Regulation of alternative splicing by p300-mediated acetylation of splicing factors. RNA (NEW YORK, N.Y.) 2019; 25:813-824. [PMID: 30988101 PMCID: PMC6573785 DOI: 10.1261/rna.069856.118] [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: 12/06/2018] [Accepted: 04/08/2019] [Indexed: 05/23/2023]
Abstract
Splicing of precursor mRNA (pre-mRNA) is an important regulatory step in gene expression. Recent evidence points to a regulatory role of chromatin-related proteins in alternative splicing regulation. Using an unbiased approach, we have identified the acetyltransferase p300 as a key chromatin-related regulator of alternative splicing. p300 promotes genome-wide exon inclusion in both a transcription-dependent and -independent manner. Using CD44 as a paradigm, we found that p300 regulates alternative splicing by modulating the binding of splicing factors to pre-mRNA. Using a tethering strategy, we found that binding of p300 to the CD44 promoter region promotes CD44v exon inclusion independently of RNAPII transcriptional elongation rate. Promoter-bound p300 regulates alternative splicing by acetylating splicing factors, leading to exclusion of hnRNP M from CD44 pre-mRNA and activation of Sam68. p300-mediated CD44 alternative splicing reduces cell motility and promotes epithelial features. Our findings reveal a chromatin-related mechanism of alternative splicing regulation and demonstrate its impact on cellular function.
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Affiliation(s)
- Ahmad Siam
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mai Baker
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Leah Amit
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Gal Regev
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Alona Rabner
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Rauf Ahmad Najar
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mercedes Bentata
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Sara Dahan
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Klil Cohen
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Sarah Araten
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Yuval Nevo
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Gillian Kay
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | | | - Maayan Salton
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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13
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Haynes BC, Blidner RA, Cardwell RD, Zeigler R, Gokul S, Thibert JR, Chen L, Fujimoto J, Papadimitrakopoulou VA, Wistuba II, Latham GJ. An Integrated Next-Generation Sequencing System for Analyzing DNA Mutations, Gene Fusions, and RNA Expression in Lung Cancer. Transl Oncol 2019; 12:836-845. [PMID: 30981944 PMCID: PMC6463765 DOI: 10.1016/j.tranon.2019.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/21/2019] [Indexed: 12/25/2022] Open
Abstract
We developed and characterized a next-generation sequencing (NGS) technology for streamlined analysis of DNA and RNA using low-input, low-quality cancer specimens. A single-workflow, targeted NGS panel for non-small cell lung cancer (NSCLC) was designed covering 135 RNA and 55 DNA disease-relevant targets. This multiomic panel was used to assess 219 formalin-fixed paraffin-embedded NSCLC surgical resections and core needle biopsies. Mutations and expression phenotypes were identified consistent with previous large-scale genomic studies, including mutually exclusive DNA and RNA oncogenic driver events. Evaluation of a second cohort of low cell count fine-needle aspirate smears from the BATTLE-2 trial yielded 97% agreement with an independent, validated NGS panel that was used with matched surgical specimens. Collectively, our data indicate that broad, clinically actionable insights that previously required independent assays, workflows, and analyses to assess both DNA and RNA can be conjoined in a first-tier, highly multiplexed NGS test, thereby providing faster, simpler, and more economical results.
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Affiliation(s)
| | | | | | | | | | | | | | - Junya Fujimoto
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Vassiliki A Papadimitrakopoulou
- Department of Thoracic/Head and Neck Medical Oncology, Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ignacio I Wistuba
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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14
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Rambout X, Dequiedt F, Maquat LE. Beyond Transcription: Roles of Transcription Factors in Pre-mRNA Splicing. Chem Rev 2017; 118:4339-4364. [PMID: 29251915 DOI: 10.1021/acs.chemrev.7b00470] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Whereas individual steps of protein-coding gene expression in eukaryotes can be studied in isolation in vitro, it has become clear that these steps are intimately connected within cells. Connections not only ensure quality control but also fine-tune the gene expression process, which must adapt to environmental changes while remaining robust. In this review, we systematically present proven and potential mechanisms by which sequence-specific DNA-binding transcription factors can alter gene expression beyond transcription initiation and regulate pre-mRNA splicing, and thereby mRNA isoform production, by (i) influencing transcription elongation rates, (ii) binding to pre-mRNA to recruit splicing factors, and/or (iii) blocking the association of splicing factors with pre-mRNA. We propose various mechanistic models throughout the review, in some cases without explicit supportive evidence, in hopes of providing fertile ground for future studies.
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15
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RNA splicing in human disease and in the clinic. Clin Sci (Lond) 2017; 131:355-368. [PMID: 28202748 DOI: 10.1042/cs20160211] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/06/2016] [Accepted: 12/15/2016] [Indexed: 01/12/2023]
Abstract
Defects at the level of the pre-mRNA splicing process represent a major cause of human disease. Approximately 15-50% of all human disease mutations have been shown to alter functioning of basic and auxiliary splicing elements. These elements are required to ensure proper processing of pre-mRNA splicing molecules, with their disruption leading to misprocessing of the pre-mRNA molecule and disease. The splicing process is a complex process, with much still to be uncovered before we are able to accurately predict whether a reported genomic sequence variant (GV) represents a splicing-associated disease mutation or a harmless polymorphism. Furthermore, even when a mutation is correctly identified as affecting the splicing process, there still remains the difficulty of providing an exact evaluation of the potential impact on disease onset, severity and duration. In this review, we provide a brief overview of splicing diagnostic methodologies, from in silico bioinformatics approaches to wet lab in vitro and in vivo systems to evaluate splicing efficiencies. In particular, we provide an overview of how the latest developments in high-throughput sequencing can be applied to the clinic, and are already changing clinical approaches.
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17
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Chang WH, Niu DM, Lu CY, Lin SY, Liu TC, Chang JG. Modulation the alternative splicing of GLA (IVS4+919G>A) in Fabry disease. PLoS One 2017; 12:e0175929. [PMID: 28430823 PMCID: PMC5400244 DOI: 10.1371/journal.pone.0175929] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/03/2017] [Indexed: 12/31/2022] Open
Abstract
While a base substitution in intron 4 of GLA (IVS4+919G>A) that causes aberrant alternative splicing resulting in Fabry disease has been reported, its molecular mechanism remains unclear. Here we reported that upon IVS4+919G>A transversion, H3K36me3 was enriched across the alternatively spliced region. PSIP1, an adapter of H3K36me3, together with Hsp70 and NONO were recruited and formed a complex with SF2/ASF and SRp20, which further promoted GLA splicing. Amiloride, a splicing regulator in cancer cells, could reverse aberrant histone modification patterns and disrupt the association of splicing complex with GLA. It could also reverse aberrant GLA splicing in a PP1-dependant manner. Our findings revealed the alternative splicing mechanism of GLA (IVS4+919G>A), and a potential treatment for this specific genetic type of Fabry disease by amiloride in the future.
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Affiliation(s)
- Wen-Hsin Chang
- Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Dau-Ming Niu
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chi-Yu Lu
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shyr-Yi Lin
- Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan
- Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- * E-mail: (SYL); (TCL); (JGC)
| | - Ta-Chih Liu
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Hematology and Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail: (SYL); (TCL); (JGC)
| | - Jan-Gowth Chang
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, China Medical University, Taichung, Taiwan
- Department of Bioinformatics and Medical Engineering, Asia University, Taichung, Taiwan
- * E-mail: (SYL); (TCL); (JGC)
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18
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A saga of cancer epigenetics: linking epigenetics to alternative splicing. Biochem J 2017; 474:885-896. [PMID: 28270561 DOI: 10.1042/bcj20161047] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/29/2016] [Accepted: 01/05/2017] [Indexed: 12/14/2022]
Abstract
The discovery of an increasing number of alternative splicing events in the human genome highlighted that ∼94% of genes generate alternatively spliced transcripts that may produce different protein isoforms with diverse functions. It is now well known that several diseases are a direct and indirect consequence of aberrant splicing events in humans. In addition to the conventional mode of alternative splicing regulation by 'cis' RNA-binding sites and 'trans' RNA-binding proteins, recent literature provides enormous evidence for epigenetic regulation of alternative splicing. The epigenetic modifications may regulate alternative splicing by either influencing the transcription elongation rate of RNA polymerase II or by recruiting a specific splicing regulator via different chromatin adaptors. The epigenetic alterations and aberrant alternative splicing are known to be associated with various diseases individually, but this review discusses/highlights the latest literature on the role of epigenetic alterations in the regulation of alternative splicing and thereby cancer progression. This review also points out the need for further studies to understand the interplay between epigenetic modifications and aberrant alternative splicing in cancer progression.
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19
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TALE-directed local modulation of H3K9 methylation shapes exon recognition. Sci Rep 2016; 6:29961. [PMID: 27439481 PMCID: PMC4954949 DOI: 10.1038/srep29961] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 06/28/2016] [Indexed: 12/12/2022] Open
Abstract
In search for the function of local chromatin environment on pre-mRNA processing we established a new tool, which allows for the modification of chromatin using a targeted approach. Using Transcription Activator-Like Effector domains fused to histone modifying enzymes (TALE-HME), we show locally restricted alteration of histone methylation modulates the splicing of target exons. We provide evidence that a local increase in H3K9 di- and trimethylation promotes inclusion of the target alternative exon, while demethylation by JMJD2D leads to exon skipping. We further demonstrate that H3K9me3 is localized on internal exons genome-wide suggesting a general role in splicing. Consistently, targeting of the H3K9 demethylase to a weak constitutive exon reduced co-transcriptional splicing. Together our data show H3K9 methylation within the gene body is a factor influencing recognition of both constitutive and alternative exons.
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20
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Moyon S, Huynh JL, Dutta D, Zhang F, Ma D, Yoo S, Lawrence R, Wegner M, John GR, Emery B, Lubetzki C, Franklin RJM, Fan G, Zhu J, Dupree JL, Casaccia P. Functional Characterization of DNA Methylation in the Oligodendrocyte Lineage. Cell Rep 2016; 15:748-760. [PMID: 27149841 DOI: 10.1016/j.celrep.2016.03.060] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 02/08/2016] [Accepted: 03/15/2016] [Indexed: 01/08/2023] Open
Abstract
Oligodendrocytes derive from progenitors (OPCs) through the interplay of epigenomic and transcriptional events. By integrating high-resolution methylomics, RNA-sequencing, and multiple transgenic lines, this study defines the role of DNMT1 in developmental myelination. We detected hypermethylation of genes related to cell cycle and neurogenesis during differentiation of OPCs, yet genetic ablation of Dnmt1 resulted in inefficient OPC expansion and severe hypomyelination associated with ataxia and tremors in mice. This phenotype was not caused by lineage switch or massive apoptosis but was characterized by a profound defect of differentiation associated with changes in exon-skipping and intron-retention splicing events and by the activation of an endoplasmic reticulum stress response. Therefore, loss of Dnmt1 in OPCs is not sufficient to induce a lineage switch but acts as an important determinant of the coordination between RNA splicing and protein synthesis necessary for myelin formation.
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Affiliation(s)
- Sarah Moyon
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jimmy L Huynh
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Dipankar Dutta
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Fan Zhang
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Dan Ma
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AH, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
| | - Seungyeul Yoo
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rebecca Lawrence
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Michael Wegner
- Institut für Biochemie, Universität Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany
| | - Gareth R John
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Corinne Goldsmith Dickinson Center for Multiple Sclerosis, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ben Emery
- Jungers Center for Neurosciences Research and Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Catherine Lubetzki
- Sorbonne Universités UPMC Université, Paris 06, UMR_S 1127, ICM-GHU Pitié-Salpêtrière, 75013 Paris, France
| | - Robin J M Franklin
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AH, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
| | - Guoping Fan
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jun Zhu
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jeffrey L Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Patrizia Casaccia
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Corinne Goldsmith Dickinson Center for Multiple Sclerosis, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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21
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Khan DH, Gonzalez C, Tailor N, Hamedani MK, Leygue E, Davie JR. Dynamic Histone Acetylation of H3K4me3 Nucleosome Regulates MCL1 Pre-mRNA Splicing. J Cell Physiol 2016; 231:2196-204. [PMID: 26864447 DOI: 10.1002/jcp.25337] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 02/08/2016] [Indexed: 01/01/2023]
Abstract
Pre-mRNA splicing is a cotranscriptional process affected by the chromatin architecture along the body of coding genes. Recruited to the pre-mRNA by splicing factors, histone deacetylases (HDACs) and K-acetyltransferases (KATs) catalyze dynamic histone acetylation along the gene. In colon carcinoma HCT 116 cells, HDAC inhibition specifically increased KAT2B occupancy as well as H3 and H4 acetylation of the H3K4 trimethylated (H3K4me3) nucleosome positioned over alternative exon 2 of the MCL1 gene, an event paralleled with the exclusion of exon 2. These results were reproduced in MDA-MB-231, but not in MCF7 breast adenocarcinoma cells. These later cells have much higher levels of demethylase KDM5B than either HCT 116 or MDA-MB-231 cells. We show that H3K4me3 steady-state levels and H3K4me3 occupancy at the end of exon 1 and over exon 2 of the MCL1 gene were lower in MCF7 than in MDA-MB-231 cells. Furthermore, in MCF7 cells, there was minimal effect of HDAC inhibition on H3/H4 acetylation and H3K4me3 levels along the MCL1 gene and no change in pre-mRNA splicing choice. These results show that, upon HDAC inhibition, the H3K4me3 mark plays a critical role in the exclusion of exon 2 from the MCL1 pre-mRNA. J. Cell. Physiol. 231: 2196-2204, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Dilshad H Khan
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Carolina Gonzalez
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Nikesh Tailor
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Mohammad K Hamedani
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Etienne Leygue
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - James R Davie
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
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22
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Millán-Ariño L, Izquierdo-Bouldstridge A, Jordan A. Specificities and genomic distribution of somatic mammalian histone H1 subtypes. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:510-9. [DOI: 10.1016/j.bbagrm.2015.10.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 11/15/2022]
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23
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Davie JR, Xu W, Delcuve GP. Histone H3K4 trimethylation: dynamic interplay with pre-mRNA splicing. Biochem Cell Biol 2016; 94:1-11. [DOI: 10.1139/bcb-2015-0065] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Histone H3 lysine 4 trimethylation (H3K4me3) is often stated as a mark of transcriptionally active promoters. However, closer study of the positioning of H3K4me3 shows the mark locating primarily after the first exon at the 5′ splice site and overlapping with a CpG island in mammalian cells. There are several enzyme complexes that are involved in the placement of the H3K4me3 mark, including multiple protein complexes containing SETD1A, SETD1B, and MLL1 enzymes (writers). CXXC1, which is associated with SETD1A and SETD1B, target these enzymes to unmethylated CpG islands. Lysine demethylases (KDM5 family members, erasers) demethylate H3K4me3. The H3K4me3 mark is recognized by several proteins (readers), including lysine acetyltransferase complexes, chromatin remodelers, and RNA bound proteins involved in pre-mRNA splicing. Interestingly, attenuation of H3K4me3 impacts pre-mRNA splicing, and inhibition of pre-mRNA splicing attenuates H3K4me3.
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Affiliation(s)
- James R. Davie
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
| | - Wayne Xu
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
| | - Genevieve P. Delcuve
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
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24
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Sorenson MR, Jha DK, Ucles SA, Flood DM, Strahl BD, Stevens SW, Kress TL. Histone H3K36 methylation regulates pre-mRNA splicing in Saccharomyces cerevisiae. RNA Biol 2016; 13:412-26. [PMID: 26821844 DOI: 10.1080/15476286.2016.1144009] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Co-transcriptional splicing takes place in the context of a highly dynamic chromatin architecture, yet the role of chromatin restructuring in coordinating transcription with RNA splicing has not been fully resolved. To further define the contribution of histone modifications to pre-mRNA splicing in Saccharomyces cerevisiae, we probed a library of histone point mutants using a reporter to monitor pre-mRNA splicing. We found that mutation of H3 lysine 36 (H3K36) - a residue methylated by Set2 during transcription elongation - exhibited phenotypes similar to those of pre-mRNA splicing mutants. We identified genetic interactions between genes encoding RNA splicing factors and genes encoding the H3K36 methyltransferase Set2 and the demethylase Jhd1 as well as point mutations of H3K36 that block methylation. Consistent with the genetic interactions, deletion of SET2, mutations modifying the catalytic activity of Set2 or H3K36 point mutations significantly altered expression of our reporter and reduced splicing of endogenous introns. These effects were dependent on the association of Set2 with RNA polymerase II and H3K36 dimethylation. Additionally, we found that deletion of SET2 reduces the association of the U2 and U5 snRNPs with chromatin. Thus, our study provides the first evidence that H3K36 methylation plays a role in co-transcriptional RNA splicing in yeast.
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Affiliation(s)
- Matthew R Sorenson
- a Graduate Program in Microbiology, The University of Texas at Austin , Austin , Texas , USA
| | - Deepak K Jha
- b Department of Biochemistry and Biophysics , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina , USA
| | - Stefanie A Ucles
- c Department of Biology , The College of New Jersey , Ewing , NJ , USA
| | - Danielle M Flood
- c Department of Biology , The College of New Jersey , Ewing , NJ , USA
| | - Brian D Strahl
- b Department of Biochemistry and Biophysics , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina , USA.,d Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill , Chapel Hill , North Carolina , USA
| | - Scott W Stevens
- e Department of Molecular Biosciences , University of Texas at Austin , Austin , Texas , USA.,f Institute for Cellular and Molecular Biology, University of Texas at Austin , Austin , Texas , USA
| | - Tracy L Kress
- c Department of Biology , The College of New Jersey , Ewing , NJ , USA
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25
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RNA-seq analysis of impact of PNN on gene expression and alternative splicing in corneal epithelial cells. Mol Vis 2016; 22:40-60. [PMID: 26900324 PMCID: PMC4734150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/14/2016] [Indexed: 11/05/2022] Open
Abstract
PURPOSE The specialized corneal epithelium requires differentiated properties, specific for its role at the anterior surface of the eye. Thus, tight maintenance of the differentiated qualities of the corneal epithelial is essential. Pinin (PNN) is an exon junction component (EJC) that has dramatic implications for corneal epithelial cell differentiation and may act as a stabilizer of the corneal epithelial cell phenotype. Our studies revealed that PNN is involved in transcriptional repression complexes and spliceosomal complexes, placing PNN at the fulcrum between chromatin and mRNA splicing. Transcriptome analysis of PNN-knockdown cells revealed clear and reproducible alterations in transcript profiles and splicing patterns of a subset of genes that would significantly impact the epithelial cell phenotype. We further investigated PNN's role in the regulation of gene expression and alternative splicing (AS) in a corneal epithelial context. METHODS Human corneal epithelial (HCET) cells that carry the doxycycline-inducible PNN-knockdown shRNA vector were used to perform RNA-seq to determine differential gene expression and differential AS events. RESULTS Multiple genes and AS events were identified as differentially expressed between PNN-knockdown and control cells. Genes upregulated by PNN knockdown included a large proportion of genes that are associated with enhanced cell migration and ECM remodeling processes, such as MMPs, ADAMs, HAS2, LAMA3, CXCRs, and UNC5C. Genes downregulated in response to PNN depletion included IGFBP5, FGD3, FGFR2, PAX6, RARG, and SOX10. AS events in PNN-knockdown cells compared to control cells were also more likely to be detected, and upregulated. In particular, 60% of exon-skipping events, detected in only one condition, were detected in PNN-knockdown cells and of the shared exon-skipping events, 92% of those differentially expressed were more frequent in the PNN knockdown. CONCLUSIONS These data suggest that lowering of PNN levels in epithelial cells results in dramatic transformation in the number and composition of splicing variants and that PNN plays a crucial role in the selection of which RNA isoforms differentiating cells produce. Many of the genes affected by PNN knockdown are known to affect the epithelial phenotype. This window into the complexity of RNA splicing in the corneal epithelium implies that PNN exerts broad influence over the regulation and maintenance of the epithelial cell phenotype.
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26
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Sotillo E, Barrett DM, Black KL, Bagashev A, Oldridge D, Wu G, Sussman R, Lanauze C, Ruella M, Gazzara MR, Martinez NM, Harrington CT, Chung EY, Perazzelli J, Hofmann TJ, Maude SL, Raman P, Barrera A, Gill S, Lacey SF, Melenhorst JJ, Allman D, Jacoby E, Fry T, Mackall C, Barash Y, Lynch KW, Maris JM, Grupp SA, Thomas-Tikhonenko A. Convergence of Acquired Mutations and Alternative Splicing of CD19 Enables Resistance to CART-19 Immunotherapy. Cancer Discov 2015; 5:1282-95. [PMID: 26516065 DOI: 10.1158/2159-8290.cd-15-1020] [Citation(s) in RCA: 896] [Impact Index Per Article: 99.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/01/2015] [Indexed: 01/20/2023]
Abstract
UNLABELLED The CD19 antigen, expressed on most B-cell acute lymphoblastic leukemias (B-ALL), can be targeted with chimeric antigen receptor-armed T cells (CART-19), but relapses with epitope loss occur in 10% to 20% of pediatric responders. We detected hemizygous deletions spanning the CD19 locus and de novo frameshift and missense mutations in exon 2 of CD19 in some relapse samples. However, we also discovered alternatively spliced CD19 mRNA species, including one lacking exon 2. Pull-down/siRNA experiments identified SRSF3 as a splicing factor involved in exon 2 retention, and its levels were lower in relapsed B-ALL. Using genome editing, we demonstrated that exon 2 skipping bypasses exon 2 mutations in B-ALL cells and allows expression of the N-terminally truncated CD19 variant, which fails to trigger killing by CART-19 but partly rescues defects associated with CD19 loss. Thus, this mechanism of resistance is based on a combination of deleterious mutations and ensuing selection for alternatively spliced RNA isoforms. SIGNIFICANCE CART-19 yield 70% response rates in patients with B-ALL, but also produce escape variants. We discovered that the underlying mechanism is the selection for preexisting alternatively spliced CD19 isoforms with the compromised CART-19 epitope. This mechanism suggests a possibility of targeting alternative CD19 ectodomains, which could improve survival of patients with B-cell neoplasms.
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Affiliation(s)
- Elena Sotillo
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - David M Barrett
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Kathryn L Black
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Asen Bagashev
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Derek Oldridge
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Glendon Wu
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robyn Sussman
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Claudia Lanauze
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Cell & Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Marco Ruella
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Matthew R Gazzara
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. Department of Biochemistry & Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nicole M Martinez
- Department of Biochemistry & Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Colleen T Harrington
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Cell & Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elaine Y Chung
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Jessica Perazzelli
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Ted J Hofmann
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Shannon L Maude
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Pichai Raman
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Alejandro Barrera
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Saar Gill
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Simon F Lacey
- Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jan J Melenhorst
- Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - David Allman
- Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elad Jacoby
- Pediatric Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - Terry Fry
- Pediatric Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - Crystal Mackall
- Pediatric Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - Yoseph Barash
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kristen W Lynch
- Department of Biochemistry & Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - John M Maris
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Stephan A Grupp
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Andrei Thomas-Tikhonenko
- Division of Cancer Pathobiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. Cell & Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
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Mayor R, Izquierdo-Bouldstridge A, Millán-Ariño L, Bustillos A, Sampaio C, Luque N, Jordan A. Genome distribution of replication-independent histone H1 variants shows H1.0 associated with nucleolar domains and H1X associated with RNA polymerase II-enriched regions. J Biol Chem 2015; 290:7474-91. [PMID: 25645921 DOI: 10.1074/jbc.m114.617324] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Unlike core histones, the linker histone H1 family is more evolutionarily diverse, and many organisms have multiple H1 variants or subtypes. In mammals, the H1 family includes seven somatic H1 variants; H1.1 to H1.5 are expressed in a replication-dependent manner, whereas H1.0 and H1X are replication-independent. Using ChIP-sequencing data and cell fractionation, we have compared the genomic distribution of H1.0 and H1X in human breast cancer cells, in which we previously observed differential distribution of H1.2 compared with the other subtypes. We have found H1.0 to be enriched at nucleolus-associated DNA repeats and chromatin domains, whereas H1X is associated with coding regions, RNA polymerase II-enriched regions, and hypomethylated CpG islands. Further, H1X accumulates within constitutive or included exons and retained introns and toward the 3' end of expressed genes. Inducible H1X knockdown does not affect cell proliferation but dysregulates a subset of genes related to cell movement and transport. In H1X-depleted cells, the promoters of up-regulated genes are not occupied specifically by this variant, have a lower than average H1 content, and, unexpectedly, do not form an H1 valley upon induction. We conclude that H1 variants are not distributed evenly across the genome and may participate with some specificity in chromatin domain organization or gene regulation.
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Affiliation(s)
- Regina Mayor
- From the Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Catalonia 08028 Spain
| | - Andrea Izquierdo-Bouldstridge
- From the Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Catalonia 08028 Spain
| | - Lluís Millán-Ariño
- From the Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Catalonia 08028 Spain
| | - Alberto Bustillos
- From the Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Catalonia 08028 Spain
| | - Cristina Sampaio
- From the Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Catalonia 08028 Spain
| | - Neus Luque
- From the Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Catalonia 08028 Spain
| | - Albert Jordan
- From the Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Catalonia 08028 Spain
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28
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Schüler A, Ghanbarian AT, Hurst LD. Purifying selection on splice-related motifs, not expression level nor RNA folding, explains nearly all constraint on human lincRNAs. Mol Biol Evol 2014; 31:3164-83. [PMID: 25158797 PMCID: PMC4245815 DOI: 10.1093/molbev/msu249] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
There are two strong and equally important predictors of rates of human protein evolution: The amount the gene is expressed and the proportion of exonic sequence devoted to control splicing, mediated largely by selection on exonic splice enhancer (ESE) motifs. Is the same true for noncoding RNAs, known to be under very weak purifying selection? Prior evidence suggests that selection at splice sites in long intergenic noncoding RNAs (lincRNAs) is important. We now report multiple lines of evidence indicating that the great majority of purifying selection operating on lincRNAs in humans is splice related. Splice-related parameters explain much of the between-gene variation in evolutionary rate in humans. Expression rate is not a relevant predictor, although expression breadth is weakly so. In contrast to protein-coding RNAs, we observe no relationship between evolutionary rate and lincRNA stability. As in protein-coding genes, ESEs are especially abundant near splice junctions and evolve slower than non-ESE sequence equidistant from boundaries. Nearly all constraint in lincRNAs is at exon ends (N.B. the same is not witnessed in Drosophila). Although we cannot definitely answer the question as to why splice-related selection is so important, we find no evidence that splicing might enable the nonsense-mediated decay pathway to capture transcripts incorrectly processed by ribosomes. We find evidence consistent with the notion that splicing modifies the underlying chromatin through recruitment of splice-coupled chromatin modifiers, such as CHD1, which in turn might modulate neighbor gene activity. We conclude that most selection on human lincRNAs is splice mediated and suggest that the possibility of splice-chromatin coupling is worthy of further scrutiny.
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Affiliation(s)
- Andreas Schüler
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Avazeh T Ghanbarian
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Laurence D Hurst
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
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29
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Schoborg T, Labrador M. Expanding the roles of chromatin insulators in nuclear architecture, chromatin organization and genome function. Cell Mol Life Sci 2014; 71:4089-113. [PMID: 25012699 PMCID: PMC11113341 DOI: 10.1007/s00018-014-1672-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 01/08/2023]
Abstract
Of the numerous classes of elements involved in modulating eukaryotic chromosome structure and function, chromatin insulators arguably remain the most poorly understood in their contribution to these processes in vivo. Indeed, our view of chromatin insulators has evolved dramatically since their chromatin boundary and enhancer blocking properties were elucidated roughly a quarter of a century ago as a result of recent genome-wide, high-throughput methods better suited to probing the role of these elements in their native genomic contexts. The overall theme that has emerged from these studies is that chromatin insulators function as general facilitators of higher-order chromatin loop structures that exert both physical and functional constraints on the genome. In this review, we summarize the result of recent work that supports this idea as well as a number of other studies linking these elements to a diverse array of nuclear processes, suggesting that chromatin insulators exert master control over genome organization and behavior.
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Affiliation(s)
- Todd Schoborg
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
- Present Address: Laboratory of Molecular Machines and Tissue Architecture, Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Dr Rm 2122, Bethesda, MD 20892 USA
| | - Mariano Labrador
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
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30
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Regulation of gene expression programmes by serine–arginine rich splicing factors. Semin Cell Dev Biol 2014; 32:11-21. [DOI: 10.1016/j.semcdb.2014.03.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/11/2014] [Indexed: 12/21/2022]
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31
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Dušková E, Hnilicová J, Staněk D. CRE promoter sites modulate alternative splicing via p300-mediated histone acetylation. RNA Biol 2014; 11:865-74. [PMID: 25019513 DOI: 10.4161/rna.29441] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Histone acetylation modulates alternative splicing of several hundred genes. Here, we tested the role of the histone acetyltransferase p300 in alternative splicing and showed that knockdown of p300 promotes inclusion of the fibronectin (FN1) alternative EDB exon. p300 associates with CRE sites in the promoter via the CREB transcription factor. We created mini-gene reporters driven by an artificial promoter containing CRE sites. Both deletion and mutation of the CRE site affected EDB alternative splicing in the same manner as p300 knockdown. Next we showed that p300 controls histone H4 acetylation along the FN1 gene. Consistently, p300 depletion and CRE deletion/mutation both reduced histone H4 acetylation on mini-gene reporters. Finally, we provide evidence that the effect of CRE inactivation on H4 acetylation and alternative splicing is counteracted by the inhibition of histone deacetylases. Together, these data suggest that histone acetylation could be one of the mechanisms how promoter and promoter binding proteins influence alternative splicing.
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Affiliation(s)
- Eva Dušková
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jarmila Hnilicová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - David Staněk
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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32
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Hérissant L, Moehle EA, Bertaccini D, Van Dorsselaer A, Schaeffer-Reiss C, Guthrie C, Dargemont C. H2B ubiquitylation modulates spliceosome assembly and function in budding yeast. Biol Cell 2014; 106:126-38. [PMID: 24476359 DOI: 10.1111/boc.201400003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 01/24/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND INFORMATION Commitment to splicing occurs co-transcriptionally, but a major unanswered question is the extent to which various modifications of chromatin, the template for transcription in vivo, contribute to the regulation of splicing. RESULTS Here, we perform genome-wide analyses showing that inhibition of specific marks - H2B ubiquitylation, H3K4 methylation and H3K36 methylation - perturbs splicing in budding yeast, with each modification exerting gene-specific effects. Furthermore, semi-quantitative mass spectrometry on purified nuclear mRNPs and chromatin immunoprecipitation analysis on intron-containing genes indicated that H2B ubiquitylation, but not Set1-, Set2- or Dot1-dependent H3 methylation, stimulates recruitment of the early splicing factors, namely U1 and U2 snRNPs, onto nascent RNAs. CONCLUSIONS These results suggest that histone modifications impact splicing of distinct subsets of genes using distinct pathways.
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Affiliation(s)
- Lucas Hérissant
- Pathologie Cellulaire, University Paris Diderot, Sorbonne Paris Cité, INSERM U944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, Hôpital Saint Louis, Paris, Cedex 10, France
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33
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Role of pseudoexons and pseudointrons in human cancer. Int J Cell Biol 2013; 2013:810572. [PMID: 24204383 PMCID: PMC3800588 DOI: 10.1155/2013/810572] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/09/2013] [Indexed: 11/18/2022] Open
Abstract
In all eukaryotic organisms, pre-mRNA splicing and alternative splicing processes play an essential role in regulating the flow of information required to drive complex developmental and metabolic pathways. As a result, eukaryotic cells have developed a very efficient macromolecular machinery, called the spliceosome, to correctly recognize the pre-mRNA sequences that need to be inserted in a mature mRNA (exons) from those that should be removed (introns). In healthy individuals, alternative and constitutive splicing processes function with a high degree of precision and fidelity in order to ensure the correct working of this machinery. In recent years, however, medical research has shown that alterations at the splicing level play an increasingly important role in many human hereditary diseases, neurodegenerative processes, and especially in cancer origin and progression. In this minireview, we will focus on several genes whose association with cancer has been well established in previous studies, such as ATM, BRCA1/A2, and NF1. In particular, our objective will be to provide an overview of the known mechanisms underlying activation/repression of pseudoexons and pseudointrons; the possible utilization of these events as biomarkers of tumor staging/grading; and finally, the treatment options for reversing pathologic splicing events.
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34
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Hnilicová J, Hozeifi S, Stejskalová E, Dušková E, Poser I, Humpolíčková J, Hof M, Staněk D. The C-terminal domain of Brd2 is important for chromatin interaction and regulation of transcription and alternative splicing. Mol Biol Cell 2013; 24:3557-68. [PMID: 24048450 PMCID: PMC3826993 DOI: 10.1091/mbc.e13-06-0303] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
This study determines genes that are regulated by Brd2 and finds that, in addition to expression control, Brd2 modulates the alternative splicing of several hundred genes. The in vivo interaction of Brd2 with chromatin is analyzed, and the contributions of individual Brd2 domains to the chromatin interaction are determined. Brd2 is a member of the bromodomain extra terminal (BET) protein family, which consists of four chromatin-interacting proteins that regulate gene expression. Each BET protein contains two N-terminal bromodomains, which recognize acetylated histones, and the C-terminal protein–protein interaction domain. Using a genome-wide screen, we identify 1450 genes whose transcription is regulated by Brd2. In addition, almost 290 genes change their alternative splicing pattern upon Brd2 depletion. Brd2 is specifically localized at promoters of target genes, and our data show that Brd2 interaction with chromatin cannot be explained solely by histone acetylation. Using coimmunoprecipitation and live-cell imaging, we show that the C-terminal part is crucial for Brd2 association with chromatin. Live-cell microscopy also allows us to map the average binding time of Brd2 to chromatin and quantify the contributions of individual Brd2 domains to the interaction with chromatin. Finally, we show that bromodomains and the C-terminal domain are equally important for transcription and splicing regulation, which correlates with the role of these domains in Brd2 binding to chromatin.
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Affiliation(s)
- Jarmila Hnilicová
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic Max Planck Institute for Molecular Cell Biology and Genetics, Dresden 01307, Germany J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 182 23, Czech Republic
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35
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The ben1-1 brassinosteroid-catabolism mutation is unstable due to epigenetic modifications of the intronic T-DNA insertion. G3-GENES GENOMES GENETICS 2013; 3:1587-95. [PMID: 23893742 PMCID: PMC3755919 DOI: 10.1534/g3.113.006353] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Loss-of-function genetic analysis plays a pivotal role in elucidating individual gene function as well as interactions among gene networks. The ease of gene tagging and cloning provided by transfer DNA (T-DNA) insertion mutants have led to their heavy use by the Arabidopsis research community. However, certain aspects of T-DNA alleles require caution, as highlighted in this study of an intronic insertion mutant (ben1-1) in the BEN1 (BRI1-5 ENHANCED 1) gene. As a part of our analysis of brassinosteroid catabolic enzymes, we generated a genetic triple-mutant from a cross between the bas1-2 sob7-1 double-null (T-DNA exonic insertion mutants of phyB-4 ACTIVATION TAGGED SUPPRESSOR 1 and SUPPRESSOR OF phyB-4 7) and ben1-1. As previously described, the single ben1-1 line behaves as a transcript null. However, in the triple-mutant background ben1-1 was reverted to a partial loss-of-function allele showing enhanced levels of the wild-type-spliced transcript. Interestingly, the enhanced expression of BEN1 remained stable when the ben1-1 single-mutant was reisolated from a cross with the wild type. In addition, the two genetically identical pretriple and posttriple ben1-1 mutants also differed phenotypically. The previously functional NPTII (NEOMYCIN PHOSPHOTRANSFERASE II) T-DNA marker gene (which encodes kanamycin resistance) was no longer functional in the recovered ben1-1 allele, though the length of the T-DNA insertion and the NPTII gene sequence did not change in the pretriple and posttriple ben1-1 mutants. Methylation analysis using both restriction endonuclease activity and bisulfite conversion followed by sequencing showed that the methylation status of the T-DNA is different between the original and the recovered ben1-1. These observations demonstrate that the recovered ben1-1 mutant is epigenetically different from the original ben1-1 allele.
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36
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Khan DH, He S, Yu J, Winter S, Cao W, Seiser C, Davie JR. Protein kinase CK2 regulates the dimerization of histone deacetylase 1 (HDAC1) and HDAC2 during mitosis. J Biol Chem 2013; 288:16518-16528. [PMID: 23612983 DOI: 10.1074/jbc.m112.440446] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Histone deacetylase 1 (HDAC1) and HDAC2 are components of corepressor complexes that are involved in chromatin remodeling and regulation of gene expression by regulating dynamic protein acetylation. HDAC1 and -2 form homo- and heterodimers, and their activity is dependent upon dimer formation. Phosphorylation of HDAC1 and/or HDAC2 in interphase cells is required for the formation of HDAC corepressor complexes. In this study, we show that during mitosis, HDAC2 and, to a lesser extent, HDAC1 phosphorylation levels dramatically increase. When HDAC1 and -2 are displaced from the chromosome during metaphase, they dissociate from each other, but each enzyme remains in association with components of the HDAC corepressor complexes Sin3, NuRD, and CoREST as homodimers. Enzyme inhibition studies and mutational analyses demonstrated that protein kinase CK2-catalyzed phosphorylation of HDAC1 and -2 is crucial for the dissociation of these two enzymes. These results suggest that corepressor complexes, including HDAC1 or HDAC2 homodimers, might target different cellular proteins during mitosis.
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Affiliation(s)
- Dilshad H Khan
- Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada
| | - Shihua He
- Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada
| | - Jenny Yu
- Melanoma Medical Oncology, M.D. Anderson Cancer Center, Houston, Texas 77054
| | - Stefan Winter
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Wenguang Cao
- Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada
| | - Christian Seiser
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - James R Davie
- Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada.
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37
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Khan DH, Davie JR. HDAC inhibitors prevent the induction of the immediate-early gene FOSL1, but do not alter the nucleosome response. FEBS Lett 2013; 587:1510-7. [PMID: 23542037 DOI: 10.1016/j.febslet.2013.03.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 03/11/2013] [Accepted: 03/18/2013] [Indexed: 11/30/2022]
Abstract
Dynamic histone acetylation, catalyzed by lysine acetyltransferases and HDACs, is critical to IEG expression. Expression of IEGs, such as FOSL1, is induced by several signal transduction pathways resulting in activation of the protein kinase MSK and phosphorylation of histone H3 at serine 10 of nucleosomes (the nucleosome response) at the upstream promoter and regulatory region of target genes. HDAC inhibitors prevent FOSL1 gene induction and the association of HDAC1, 2 and 3 with the gene body. However, HDAC inhibitors did not prevent the nucleosome response. Thus HDAC inhibitors perturb events downstream of the nucleosome response required for FOSL1 transcription initiation.
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Affiliation(s)
- Dilshad H Khan
- Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
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38
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Black JC, Van Rechem C, Whetstine JR. Histone lysine methylation dynamics: establishment, regulation, and biological impact. Mol Cell 2013. [PMID: 23200123 DOI: 10.1016/j.molcel.2012.11.006] [Citation(s) in RCA: 848] [Impact Index Per Article: 77.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Histone lysine methylation has emerged as a critical player in the regulation of gene expression, cell cycle, genome stability, and nuclear architecture. Over the past decade, a tremendous amount of progress has led to the characterization of methyl modifications and the lysine methyltransferases (KMTs) and lysine demethylases (KDMs) that regulate them. Here, we review the discovery and characterization of the KMTs and KDMs and the methyl modifications they regulate. We discuss the localization of the KMTs and KDMs as well as the distribution of lysine methylation throughout the genome. We highlight how these data have shaped our view of lysine methylation as a key determinant of complex chromatin states. Finally, we discuss the regulation of KMTs and KDMs by proteasomal degradation, posttranscriptional mechanisms, and metabolic status. We propose key questions for the field and highlight areas that we predict will yield exciting discoveries in the years to come.
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Affiliation(s)
- Joshua C Black
- Massachusetts General Hospital Cancer Center and Department of Medicine, Harvard Medical School, 13(th) Street, Charlestown, MA 02129, USA
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39
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Keren-Shaul H, Lev-Maor G, Ast G. Pre-mRNA splicing is a determinant of nucleosome organization. PLoS One 2013; 8:e53506. [PMID: 23326444 PMCID: PMC3542351 DOI: 10.1371/journal.pone.0053506] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 11/29/2012] [Indexed: 11/19/2022] Open
Abstract
Chromatin organization affects alternative splicing and previous studies have shown that exons have increased nucleosome occupancy compared with their flanking introns. To determine whether alternative splicing affects chromatin organization we developed a system in which the alternative splicing pattern switched from inclusion to skipping as a function of time. Changes in nucleosome occupancy were correlated with the change in the splicing pattern. Surprisingly, strengthening of the 5' splice site or strengthening the base pairing of U1 snRNA with an internal exon abrogated the skipping of the internal exons and also affected chromatin organization. Over-expression of splicing regulatory proteins also affected the splicing pattern and changed nucleosome occupancy. A specific splicing inhibitor was used to show that splicing impacts nucleosome organization endogenously. The effect of splicing on the chromatin required a functional U1 snRNA base pairing with the 5' splice site, but U1 pairing was not essential for U1 snRNA enhancement of transcription. Overall, these results suggest that splicing can affect chromatin organization.
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Affiliation(s)
- Hadas Keren-Shaul
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Galit Lev-Maor
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gil Ast
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
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40
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Sabra M, Texier P, El Maalouf J, Lomonte P. The tudor protein survival motor neuron (SMN) is a chromatin-binding protein that interacts with methylated histone H3 lysine 79. J Cell Sci 2013; 126:3664-77. [DOI: 10.1242/jcs.126003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a muscular disease characterized by the death of motoneurons, and is a major genetic cause of infant mortality. Mutations in the SMN1 gene, which encodes the protein survival motor neuron (SMN), are responsible for the disease due to compensation deficit. SMN belongs to the Tudor domain protein family, whose members are known to interact with methylated arginine (R) or lysine (K) residues. SMN has well-defined roles in the metabolism of small non-coding ribonucleoproteins (snRNPs) and spliceosome activity. We previously showed that SMN relocated to damaged interphase centromeres, together with the Cajal body-associated proteins coilin and fibrillarin, during the so-called interphase centromere damage response (iCDR). Here we reveal that SMN is a chromatin-binding protein that specifically interacts with methylated histone H3K79, a gene expression- and splicing-associated histone modification. SMN relocation to damaged centromeres requires its functional Tudor domain and activity of the H3K79 methyltransferase DOT1-L. In vitro pull-down assays showed that SMN interacts with H3K79me1,2 via its functional Tudor domain. Chromatin immunoprecipitation confirmed that SMN binds to H3K79me1,2-containing chromatin in iCDR-induced cells. These data reveal a novel SMN property in the detection of specific chromatin modifications, and shed new light on the involvement of a putative epigenetic dimension to the occurrence of SMA.
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41
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Hsin JP, Manley JL. The RNA polymerase II CTD coordinates transcription and RNA processing. Genes Dev 2012; 26:2119-37. [PMID: 23028141 DOI: 10.1101/gad.200303.112] [Citation(s) in RCA: 463] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The C-terminal domain (CTD) of the RNA polymerase II largest subunit consists of multiple heptad repeats (consensus Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7), varying in number from 26 in yeast to 52 in vertebrates. The CTD functions to help couple transcription and processing of the nascent RNA and also plays roles in transcription elongation and termination. The CTD is subject to extensive post-translational modification, most notably phosphorylation, during the transcription cycle, which modulates its activities in the above processes. Therefore, understanding the nature of CTD modifications, including how they function and how they are regulated, is essential to understanding the mechanisms that control gene expression. While the significance of phosphorylation of Ser2 and Ser5 residues has been studied and appreciated for some time, several additional modifications have more recently been added to the CTD repertoire, and insight into their function has begun to emerge. Here, we review findings regarding modification and function of the CTD, highlighting the important role this unique domain plays in coordinating gene activity.
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Affiliation(s)
- Jing-Ping Hsin
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Abstract
Epigenetic mechanisms regulate expression of the genome to generate various cell types during development or orchestrate cellular responses to external stimuli. Recent studies highlight that bacteria can affect the chromatin structure and transcriptional program of host cells by influencing diverse epigenetic factors (i.e., histone modifications, DNA methylation, chromatin-associated complexes, noncoding RNAs, and RNA splicing factors). In this article, we first review the molecular bases of the epigenetic language and then describe the current state of research regarding how bacteria can alter epigenetic marks and machineries. Bacterial-induced epigenetic deregulations may affect host cell function either to promote host defense or to allow pathogen persistence. Thus, pathogenic bacteria can be considered as potential epimutagens able to reshape the epigenome. Their effects might generate specific, long-lasting imprints on host cells, leading to a memory of infection that influences immunity and might be at the origin of unexplained diseases.
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Affiliation(s)
- Hélène Bierne
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris F-75015, France.
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43
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Khan DH, Jahan S, Davie JR. Pre-mRNA splicing: role of epigenetics and implications in disease. Adv Biol Regul 2012; 52:377-388. [PMID: 22884031 DOI: 10.1016/j.jbior.2012.04.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 04/23/2012] [Indexed: 06/01/2023]
Abstract
Epigenetics refer to a variety of processes that have long-term effects on gene expression programs without changes in DNA sequence. Key players in epigenetic control are histone modifications and DNA methylation which, in concert with chromatin remodeling complexes, nuclear architecture and microRNAs, define the chromatin structure of a gene and its transcriptional activity. There is a growing awareness that histone modifications and chromatin organization influence pre-mRNA splicing. Further there is emerging evidence that pre-mRNA splicing itself influences chromatin organization. In the mammalian genome around 95% of multi-exon genes generate alternatively spliced transcripts, the products of which create proteins with different functions. It is now established that several human diseases are a direct consequence of aberrant splicing events. In this review we present the interplay between epigenetic mechanisms and splicing regulation, as well as discuss recent studies on the role of histone deacetylases in splicing activities.
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Affiliation(s)
- Dilshad H Khan
- Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, R3E 3P4 Canada
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Norris AD, Calarco JA. Emerging Roles of Alternative Pre-mRNA Splicing Regulation in Neuronal Development and Function. Front Neurosci 2012; 6:122. [PMID: 22936897 PMCID: PMC3424503 DOI: 10.3389/fnins.2012.00122] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 08/02/2012] [Indexed: 12/21/2022] Open
Abstract
Alternative pre-mRNA splicing has the potential to greatly diversify the repertoire of transcripts in multicellular organisms. Increasing evidence suggests that this expansive layer of gene regulation plays a particularly important role in the development and function of the nervous system, one of the most complex organ systems found in nature. In this review, we highlight recent studies that continue to emphasize the influence and contribution of alternative splicing regulation to various aspects of neuronal development in addition to its role in the mature nervous system.
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Affiliation(s)
- Adam D Norris
- FAS Center for Systems Biology, Harvard University Cambridge, MA, USA
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45
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Frequency and prognostic impact of mutations in SRSF2, U2AF1, and ZRSR2 in patients with myelodysplastic syndromes. Blood 2012; 119:3578-84. [PMID: 22389253 DOI: 10.1182/blood-2011-12-399337] [Citation(s) in RCA: 339] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mutations in genes of the splicing machinery have been described recently in myelodysplastic syndromes (MDS). In the present study, we examined a cohort of 193 MDS patients for mutations in SRSF2, U2AF1 (synonym U2AF35), ZRSR2, and, as described previously, SF3B1, in the context of other molecular markers, including mutations in ASXL1, RUNX1, NRAS, TP53, IDH1, IDH2, NPM1, and DNMT3A. Mutations in SRSF2, U2AF1, ZRSR2, and SF3B1 were found in 24 (12.4%), 14 (7.3%), 6 (3.1%), and 28 (14.5%) patients, respectively, corresponding to a total of 67 of 193 MDS patients (34.7%). SRSF2 mutations were associated with RUNX1 (P < .001) and IDH1 (P = .013) mutations, whereas U2AF1 mutations were associated with ASXL1 (P = .005) and DNMT3A (P = .004) mutations. In univariate analysis, mutated SRSF2 predicted shorter overall survival and more frequent acute myeloid leukemia progression compared with wild-type SRSF2, whereas mutated U2AF1, ZRSR2, and SF3B1 had no impact on patient outcome. In multivariate analysis, SRSF2 remained an independent poor risk marker for overall survival (hazard ratio = 2.3; 95% confidence interval, 1.28-4.13; P = .017) and acute myeloid leukemia progression (hazard ratio = 2.83; 95% confidence interval, 1.31-6.12; P = .008). These results show a negative prognostic impact of SRSF2 mutations in MDS. SRSF2 mutations may become useful for clinical risk stratification and treatment decisions in the future.
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Johnson TL, Vilardell J. Regulated pre-mRNA splicing: the ghostwriter of the eukaryotic genome. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:538-45. [PMID: 22248620 DOI: 10.1016/j.bbagrm.2011.12.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 12/27/2011] [Accepted: 12/29/2011] [Indexed: 11/28/2022]
Abstract
Intron removal is at the heart of mRNA synthesis. It is mediated by one of the cell's largest complexes, the spliceosome. Yet, the fundamental chemistry involved is simple. In this review we will address how the spliceosome acts in diverse ways to optimize gene expression in order to meet the cell's needs. This is done largely by regulating the splicing of key transcripts encoding products that control gene expression pathways. This widespread role is evident even in the yeast Saccharomyces cerevisiae, where many introns appear to have been lost; yet how this control is being achieved is known only in a few cases. Here we explore the relevant examples and posit hypotheses whereby regulated splicing fine-tunes gene expression pathways to maintain cell homeostasis. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Tracy L Johnson
- Division of Biological Sciences, University of California, San Diego, CA, USA.
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Passoni M, De Conti L, Baralle M, Buratti E. UG repeats/TDP-43 interactions near 5' splice sites exert unpredictable effects on splicing modulation. J Mol Biol 2011; 415:46-60. [PMID: 22100394 DOI: 10.1016/j.jmb.2011.11.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 10/18/2011] [Accepted: 11/01/2011] [Indexed: 12/14/2022]
Abstract
TDP-43 is a nuclear protein implicated in the pathogenesis of several neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration, with broad involvement in numerous stages of RNA processing ranging from transcription to translation. In diseased neurons, TDP-43 mostly aggregates in the cytoplasm, suggesting that a loss of protein function in the nucleus may play an important role in neurodegeneration. A better understanding of TDP-43 general nuclear functions is therefore an essential step to evaluate this possibility. Presently, the TDP-43 best-characterized functional property is its ability to modulate pre-mRNA splicing when binding in proximity of 3'SS acceptor sequences. In this work, using a variety of artificial and natural splicing substrates, we have investigated the effects of TDP-43 binding to UG repeats in the vicinity of 5'SS donor sequences. In general, our results show that UG repeats are not powerful splicing regulatory elements when located near to exonic 5'SS sequences. However, in cases like the BRCA1, ETF1, and RXRG genes, TDP-43 binding to natural UG-repeated sequences can act as either an activator or a suppressor of 5'SS recognition, depending on splice site strength and on the presence of additional splicing regulatory sequences. The results of this analysis suggest that a role of UG repeats/TDP-43 in 5'SS recognition may exists and may become critical in the presence of mutations that weaken the 5'SS. The general rule that can be drawn at the moment is that the importance of UG repeats near 5' splice sites should always be experimentally validated on a case-by-case basis.
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Affiliation(s)
- Monica Passoni
- International Centre for Genetic Engineering and Biotechnology, 34012 Trieste, Italy
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