1
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Foong YH, Caldwell B, Thorvaldsen JL, Krapp C, Mesaros CA, Zhou W, Kohli RM, Bartolomei MS. TET1 displays catalytic and non-catalytic functions in the adult mouse cortex. Epigenetics 2024; 19:2374979. [PMID: 38970823 PMCID: PMC11229741 DOI: 10.1080/15592294.2024.2374979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 06/26/2024] [Indexed: 07/08/2024] Open
Abstract
TET1/2/3 dioxygenases iteratively demethylate 5-methylcytosine, beginning with the formation of 5-hydroxymethylcytosine (5hmC). The post-mitotic brain maintains higher levels of 5hmC than most peripheral tissues, and TET1 ablation studies have underscored the critical role of TET1 in brain physiology. However, deletion of Tet1 precludes the disentangling of the catalytic and non-catalytic functions of TET1. Here, we dissect these functions of TET1 by comparing adult cortex of Tet1 wildtype (Tet1 WT), a novel Tet1 catalytically dead mutant (Tet1 HxD), and Tet1 knockout (Tet1 KO) mice. Using DNA methylation array, we uncover that Tet1 HxD and KO mutations perturb the methylation status of distinct subsets of CpG sites. Gene ontology (GO) analysis on specific differential 5hmC regions indicates that TET1's catalytic activity is linked to neuronal-specific functions. RNA-Seq further shows that Tet1 mutations predominantly impact the genes that are associated with alternative splicing. Lastly, we performed High-performance Liquid Chromatography Mass-Spectrometry lipidomics on WT and mutant cortices and uncover accumulation of lysophospholipids lysophosphatidylethanolamine and lysophosphatidylcholine in Tet1 HxD cortex. In summary, we show that Tet1 HxD does not completely phenocopy Tet1 KO, providing evidence that TET1 modulates distinct cortical functions through its catalytic and non-catalytic roles.
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Affiliation(s)
- Yee Hoon Foong
- Department of Cell and Developmental Biology, Perelman School of Medicine, Smilow Center for Translational Research, Philadelphia, PA, USA
| | - Blake Caldwell
- Department of Cell and Developmental Biology, Perelman School of Medicine, Smilow Center for Translational Research, Philadelphia, PA, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Joanne L. Thorvaldsen
- Department of Cell and Developmental Biology, Perelman School of Medicine, Smilow Center for Translational Research, Philadelphia, PA, USA
| | - Christopher Krapp
- Department of Cell and Developmental Biology, Perelman School of Medicine, Smilow Center for Translational Research, Philadelphia, PA, USA
| | - Clementina A. Mesaros
- Translational Biomarkers Core, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Wanding Zhou
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Children’s Hospital of Philadelphia (CHOP), University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Smilow Center for Translational Rsearch, Philadelphia, PA, USA
| | - Rahul M. Kohli
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Smilow Center for Translational Rsearch, Philadelphia, PA, USA
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Marisa S. Bartolomei
- Department of Cell and Developmental Biology, Perelman School of Medicine, Smilow Center for Translational Research, Philadelphia, PA, USA
- Penn Epigenetics Institute, Smilow Center for Translational Rsearch, Philadelphia, PA, USA
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2
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Yustis JC, Devoucoux M, Côté J. The Functional Relationship Between RNA Splicing and the Chromatin Landscape. J Mol Biol 2024; 436:168614. [PMID: 38762032 DOI: 10.1016/j.jmb.2024.168614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/27/2024] [Accepted: 05/13/2024] [Indexed: 05/20/2024]
Abstract
Chromatin is a highly regulated and dynamic structure that has been shown to play an essential role in transcriptional and co-transcriptional regulation. In the context of RNA splicing, early evidence suggested a loose connection between the chromatin landscape and splicing. More recently, it has been shown that splicing occurs in a co-transcriptional manner, meaning that the splicing process occurs in the context of chromatin. Experimental and computational evidence have also shown that chromatin dynamics can influence the splicing process and vice versa. However, much of this evidence provides mainly correlative relationships between chromatin and splicing with just a few concrete examples providing defined molecular mechanisms by which these two processes are functionally related. Nevertheless, it is clear that chromatin and RNA splicing are tightly interconnected to one another. In this review, we highlight the current state of knowledge of the relationship between chromatin and splicing.
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Affiliation(s)
- Juan-Carlos Yustis
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Maëva Devoucoux
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada.
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3
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Sahrhage M, Paul NB, Beißbarth T, Haubrock M. The importance of DNA sequence for nucleosome positioning in transcriptional regulation. Life Sci Alliance 2024; 7:e202302380. [PMID: 38830772 PMCID: PMC11147951 DOI: 10.26508/lsa.202302380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 05/15/2024] [Accepted: 05/16/2024] [Indexed: 06/05/2024] Open
Abstract
Nucleosome positioning is a key factor for transcriptional regulation. Nucleosomes regulate the dynamic accessibility of chromatin and interact with the transcription machinery at every stage. Influences to steer nucleosome positioning are diverse, and the according importance of the DNA sequence in contrast to active chromatin remodeling has been the subject of long discussion. In this study, we evaluate the functional role of DNA sequence for all major elements along the process of transcription. We developed a random forest classifier based on local DNA structure that assesses the sequence-intrinsic support for nucleosome positioning. On this basis, we created a simple data resource that we applied genome-wide to the human genome. In our comprehensive analysis, we found a special role of DNA in mediating the competition of nucleosomes with cis-regulatory elements, in enabling steady transcription, for positioning of stable nucleosomes in exons, and for repelling nucleosomes during transcription termination. In contrast, we relate these findings to concurrent processes that generate strongly positioned nucleosomes in vivo that are not mediated by sequence, such as energy-dependent remodeling of chromatin.
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Affiliation(s)
- Malte Sahrhage
- Department of Medical Bioinformatics, University Medical Center, Göttingen, Germany
| | - Niels Benjamin Paul
- Department of Medical Bioinformatics, University Medical Center, Göttingen, Germany
- Department of Cardiology and Pneumology, University Medical Center, Göttingen, Germany
| | - Tim Beißbarth
- Department of Medical Bioinformatics, University Medical Center, Göttingen, Germany
| | - Martin Haubrock
- Department of Medical Bioinformatics, University Medical Center, Göttingen, Germany
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4
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Pascal C, Zonszain J, Hameiri O, Gargi-Levi C, Lev-Maor G, Tammer L, Levy T, Tarabeih A, Roy VR, Ben-Salmon S, Elbaz L, Eid M, Hakim T, Abu Rabe'a S, Shalev N, Jordan A, Meshorer E, Ast G. Human histone H1 variants impact splicing outcome by controlling RNA polymerase II elongation. Mol Cell 2023; 83:3801-3817.e8. [PMID: 37922872 DOI: 10.1016/j.molcel.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 08/17/2023] [Accepted: 10/05/2023] [Indexed: 11/07/2023]
Abstract
Histones shape chromatin structure and the epigenetic landscape. H1, the most diverse histone in the human genome, has 11 variants. Due to the high structural similarity between the H1s, their unique functions in transferring information from the chromatin to mRNA-processing machineries have remained elusive. Here, we generated human cell lines lacking up to five H1 subtypes, allowing us to characterize the genomic binding profiles of six H1 variants. Most H1s bind to specific sites, and binding depends on multiple factors, including GC content. The highly expressed H1.2 has a high affinity for exons, whereas H1.3 binds intronic sequences. H1s are major splicing regulators, especially of exon skipping and intron retention events, through their effects on the elongation of RNA polymerase II (RNAPII). Thus, H1 variants determine splicing fate by modulating RNAPII elongation.
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Affiliation(s)
- Corina Pascal
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Jonathan Zonszain
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ofir Hameiri
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Chen Gargi-Levi
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Galit Lev-Maor
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Luna Tammer
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tamar Levy
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anan Tarabeih
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Vanessa Rachel Roy
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Stav Ben-Salmon
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Liraz Elbaz
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Mireille Eid
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tamar Hakim
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Salima Abu Rabe'a
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nana Shalev
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Albert Jordan
- Instituto de Biologia Molecular de Barcelona (IBMB-CSIC), Carrer de Baldiri Reixac, 15, 08028 Barcelona, Spain
| | - Eran Meshorer
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, Jerusalem 91904, Israel; Edmond and Lily Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Gil Ast
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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5
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Sanchez A, Lhuillier J, Grosjean G, Ayadi L, Maenner S. The Long Non-Coding RNA ANRIL in Cancers. Cancers (Basel) 2023; 15:4160. [PMID: 37627188 PMCID: PMC10453084 DOI: 10.3390/cancers15164160] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
ANRIL (Antisense Noncoding RNA in the INK4 Locus), a long non-coding RNA encoded in the human chromosome 9p21 region, is a critical factor for regulating gene expression by interacting with multiple proteins and miRNAs. It has been found to play important roles in various cellular processes, including cell cycle control and proliferation. Dysregulation of ANRIL has been associated with several diseases like cancers and cardiovascular diseases, for instance. Understanding the oncogenic role of ANRIL and its potential as a diagnostic and prognostic biomarker in cancer is crucial. This review provides insights into the regulatory mechanisms and oncogenic significance of the 9p21 locus and ANRIL in cancer.
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Affiliation(s)
| | | | | | - Lilia Ayadi
- CNRS, Université de Lorraine, IMoPA, F-54000 Nancy, France
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6
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Alves VC, Figueiro-Silva J, Ferrer I, Carro E. Epigenetic silencing of OR and TAS2R genes expression in human orbitofrontal cortex at early stages of sporadic Alzheimer's disease. Cell Mol Life Sci 2023; 80:196. [PMID: 37405535 PMCID: PMC10322771 DOI: 10.1007/s00018-023-04845-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 06/06/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023]
Abstract
Modulation of brain olfactory (OR) and taste receptor (TASR) expression was recently reported in neurological diseases. However, there is still limited evidence of these genes' expression in the human brain and the transcriptional regulation mechanisms involved remain elusive. We explored the possible expression and regulation of selected OR and TASR in the human orbitofrontal cortex (OFC) of sporadic Alzheimer's disease (AD) and non-demented control specimens using quantitative real-time RT-PCR and ELISA. Global H3K9me3 amounts were measured on OFC total histone extracts, and H3K9me3 binding at each chemoreceptor locus was examined through native chromatin immunoprecipitation. To investigate the potential interactome of the repressive histone mark H3K9me3 in OFC specimens, native nuclear complex co-immunoprecipitation (Co-IP) was combined with reverse phase-liquid chromatography coupled to mass spectrometry analysis. Interaction between H3K9me3 and MeCP2 was validated by reciprocal Co-IP, and global MeCP2 levels were quantitated. We found that OR and TAS2R genes are expressed and markedly downregulated in OFC at early stages of sporadic AD, preceding the progressive reduction in their protein levels and the appearance of AD-associated neuropathology. The expression pattern did not follow disease progression suggesting transcriptional regulation through epigenetic mechanisms. We discovered an increase of OFC global H3K9me3 levels and a substantial enrichment of this repressive signature at ORs and TAS2Rs proximal promoter at early stages of AD, ultimately lost at advanced stages. We revealed the interaction between H3K9me3 and MeCP2 at early stages and found that MeCP2 protein is increased in sporadic AD. Findings suggest MeCP2 might be implicated in OR and TAS2R transcriptional regulation through interaction with H3K9me3, and as an early event, it may uncover a novel etiopathogenetic mechanism of sporadic AD.
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Affiliation(s)
- Victoria Cunha Alves
- Neurodegenerative Diseases Group, Hospital Universitario 12 de Octubre Research Institute (imas12), Madrid, Spain
- Network Center for Biomedical Research, Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- PhD Program in Neuroscience, Autonoma de Madrid University, Madrid, Spain
| | - Joana Figueiro-Silva
- Neurodegenerative Diseases Group, Hospital Universitario 12 de Octubre Research Institute (imas12), Madrid, Spain
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
- Department of Molecular Life Science, University of Zurich, Zurich, Switzerland
| | - Isidre Ferrer
- Network Center for Biomedical Research, Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neuropathology, Bellvitge University Hospital-IDIBELL, Barcelona, Spain
- University of Barcelona, Barcelona, Spain
| | - Eva Carro
- Neurodegenerative Diseases Group, Hospital Universitario 12 de Octubre Research Institute (imas12), Madrid, Spain
- Network Center for Biomedical Research, Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Present Address: Neurobiology of Alzheimer’s Disease Unit, Functional Unit for Research Into Chronic Diseases, Instituto de Salud Carlos III, Madrid, Spain
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7
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Binda O, Kimenyi Ishimwe AB, Galloy M, Jacquet K, Corpet A, Fradet-Turcotte A, Côté J, Lomonte P. The TUDOR domain of SMN is an H3K79 me1 histone mark reader. Life Sci Alliance 2023; 6:e202201752. [PMID: 36882285 PMCID: PMC9993015 DOI: 10.26508/lsa.202201752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/09/2023] Open
Abstract
Spinal muscular atrophy is the leading genetic cause of infant mortality and results from depleted levels of functional survival of motor neuron (SMN) protein by either deletion or mutation of the SMN1 gene. SMN is characterized by a central TUDOR domain, which mediates the association of SMN with arginine methylated (Rme) partners, such as coilin, fibrillarin, and RNA pol II (RNA polymerase II). Herein, we biochemically demonstrate that SMN also associates with histone H3 monomethylated on lysine 79 (H3K79me1), defining SMN as not only the first protein known to associate with the H3K79me1 histone modification but also the first histone mark reader to recognize both methylated arginine and lysine residues. Mutational analyzes provide evidence that SMNTUDOR associates with H3 via an aromatic cage. Importantly, most SMNTUDOR mutants found in spinal muscular atrophy patients fail to associate with H3K79me1.
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Affiliation(s)
- Olivier Binda
- Université Claude Bernard Lyon 1, CNRS UMR 5261, INSERM U1315, LabEx DEV2CAN, Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG-PGNM), Team Chromatin Dynamics, Nuclear Domains, Virus, Lyon, France
- University of Ottawa, Faculty of Medicine, Department of Cellular and Molecular Medicine, Ontario, Canada
| | - Aimé Boris Kimenyi Ishimwe
- Université Claude Bernard Lyon 1, CNRS UMR 5261, INSERM U1315, LabEx DEV2CAN, Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG-PGNM), Team Chromatin Dynamics, Nuclear Domains, Virus, Lyon, France
| | - Maxime Galloy
- Université Laval Cancer Research Center, Université Laval, Québec, Canada; Department of Molecular Biology, Medical Biochemistry and Pathology, Université Laval, Québec, Canada; and Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Québec, Canada
| | - Karine Jacquet
- Université Claude Bernard Lyon 1, CNRS UMR 5261, INSERM U1315, LabEx DEV2CAN, Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG-PGNM), Team Chromatin Dynamics, Nuclear Domains, Virus, Lyon, France
| | - Armelle Corpet
- Université Claude Bernard Lyon 1, CNRS UMR 5261, INSERM U1315, LabEx DEV2CAN, Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG-PGNM), Team Chromatin Dynamics, Nuclear Domains, Virus, Lyon, France
| | - Amélie Fradet-Turcotte
- Université Laval Cancer Research Center, Université Laval, Québec, Canada; Department of Molecular Biology, Medical Biochemistry and Pathology, Université Laval, Québec, Canada; and Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Québec, Canada
| | - Jocelyn Côté
- University of Ottawa, Faculty of Medicine, Department of Cellular and Molecular Medicine, Ontario, Canada
| | - Patrick Lomonte
- Université Claude Bernard Lyon 1, CNRS UMR 5261, INSERM U1315, LabEx DEV2CAN, Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG-PGNM), Team Chromatin Dynamics, Nuclear Domains, Virus, Lyon, France
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8
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Girardini KN, Olthof AM, Kanadia RN. Introns: the "dark matter" of the eukaryotic genome. Front Genet 2023; 14:1150212. [PMID: 37260773 PMCID: PMC10228655 DOI: 10.3389/fgene.2023.1150212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/02/2023] Open
Abstract
The emergence of introns was a significant evolutionary leap that is a major distinguishing feature between prokaryotic and eukaryotic genomes. While historically introns were regarded merely as the sequences that are removed to produce spliced transcripts encoding functional products, increasingly data suggests that introns play important roles in the regulation of gene expression. Here, we use an intron-centric lens to review the role of introns in eukaryotic gene expression. First, we focus on intron architecture and how it may influence mechanisms of splicing. Second, we focus on the implications of spliceosomal snRNAs and their variants on intron splicing. Finally, we discuss how the presence of introns and the need to splice them influences transcription regulation. Despite the abundance of introns in the eukaryotic genome and their emerging role regulating gene expression, a lot remains unexplored. Therefore, here we refer to introns as the "dark matter" of the eukaryotic genome and discuss some of the outstanding questions in the field.
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Affiliation(s)
- Kaitlin N. Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
| | - Anouk M. Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Rahul N. Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, United States
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9
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Rogalska ME, Vivori C, Valcárcel J. Regulation of pre-mRNA splicing: roles in physiology and disease, and therapeutic prospects. Nat Rev Genet 2023; 24:251-269. [PMID: 36526860 DOI: 10.1038/s41576-022-00556-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2022] [Indexed: 12/23/2022]
Abstract
The removal of introns from mRNA precursors and its regulation by alternative splicing are key for eukaryotic gene expression and cellular function, as evidenced by the numerous pathologies induced or modified by splicing alterations. Major recent advances have been made in understanding the structures and functions of the splicing machinery, in the description and classification of physiological and pathological isoforms and in the development of the first therapies for genetic diseases based on modulation of splicing. Here, we review this progress and discuss important remaining challenges, including predicting splice sites from genomic sequences, understanding the variety of molecular mechanisms and logic of splicing regulation, and harnessing this knowledge for probing gene function and disease aetiology and for the design of novel therapeutic approaches.
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Affiliation(s)
- Malgorzata Ewa Rogalska
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Claudia Vivori
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- The Francis Crick Institute, London, UK
| | - Juan Valcárcel
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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10
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Seczynska M, Lehner PJ. The sound of silence: mechanisms and implications of HUSH complex function. Trends Genet 2023; 39:251-267. [PMID: 36754727 DOI: 10.1016/j.tig.2022.12.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/14/2022] [Accepted: 12/30/2022] [Indexed: 02/08/2023]
Abstract
The vertebrate genome is under constant threat of invasion by genetic parasites. Whether the host can immediately recognize and respond to invading elements has been unclear. The discovery of the human silencing hub (HUSH) complex, and the finding that it provides immediate protection from genome invasion by silencing products of reverse transcription, have important implications for mammalian genome evolution. In this review, we summarize recent insights into HUSH function and describe how cellular introns provide a novel means of self-nonself discrimination, allowing HUSH to recognize and transcriptionally repress a broad range of intronless genetic elements. We discuss how HUSH contributes to genome evolution, and highlight studies reporting the critical role of HUSH in development and implicating HUSH in the control of immune signaling and cancer progression.
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Affiliation(s)
- Marta Seczynska
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK.
| | - Paul J Lehner
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK.
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11
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Petrova V, Song R, Nordström KJV, Walter J, Wong JJL, Armstrong N, Rasko JEJ, Schmitz U. Increased chromatin accessibility facilitates intron retention in specific cell differentiation states. Nucleic Acids Res 2022; 50:11563-11579. [PMID: 36354002 PMCID: PMC9723627 DOI: 10.1093/nar/gkac994] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/05/2022] [Accepted: 10/18/2022] [Indexed: 11/11/2022] Open
Abstract
Dynamic intron retention (IR) in vertebrate cells is of widespread biological importance. Aberrant IR is associated with numerous human diseases including several cancers. Despite consistent reports demonstrating that intrinsic sequence features can help introns evade splicing, conflicting findings about cell type- or condition-specific IR regulation by trans-regulatory and epigenetic mechanisms demand an unbiased and systematic analysis of IR in a controlled experimental setting. We integrated matched mRNA sequencing (mRNA-Seq), whole-genome bisulfite sequencing (WGBS), nucleosome occupancy methylome sequencing (NOMe-Seq) and chromatin immunoprecipitation sequencing (ChIP-Seq) data from primary human myeloid and lymphoid cells. Using these multi-omics data and machine learning, we trained two complementary models to determine the role of epigenetic factors in the regulation of IR in cells of the innate immune system. We show that increased chromatin accessibility, as revealed by nucleosome-free regions, contributes substantially to the retention of introns in a cell-specific manner. We also confirm that intrinsic characteristics of introns are key for them to evade splicing. This study suggests an important role for chromatin architecture in IR regulation. With an increasing appreciation that pathogenic alterations are linked to RNA processing, our findings may provide useful insights for the development of novel therapeutic approaches that target aberrant splicing.
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Affiliation(s)
- Veronika Petrova
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown 2050, Australia,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia
| | - Renhua Song
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | | | - Karl J V Nordström
- Laboratory of EpiGenetics, Saarland University, Campus A2 4, D-66123 Saarbrücken, Germany
| | - Jörn Walter
- Laboratory of EpiGenetics, Saarland University, Campus A2 4, D-66123 Saarbrücken, Germany
| | - Justin J L Wong
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | - Nicola J Armstrong
- Mathematics and Statistics, Curtin University, Bentley, WA 6102, Australia
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12
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Wiedner HJ, Torres EV, Blue RE, Tsai Y, Parker J, Giudice J. SET domain containing 2 (SETD2) influences metabolism and alternative splicing during myogenesis. FEBS J 2022; 289:6799-6816. [PMID: 35724320 PMCID: PMC9796740 DOI: 10.1111/febs.16553] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 05/13/2022] [Accepted: 06/10/2022] [Indexed: 01/14/2023]
Abstract
Epigenetic regulatory mechanisms are increasingly recognized as crucial determinants of cellular specification and differentiation. During muscle cell differentiation (myogenesis), extensive remodelling of histone acetylation and methylation occurs. Several of these histone modifications aid in the expression of muscle-specific genes and the silencing of genes that block lineage commitment. Therefore, the identification of new epigenetic regulatory mechanisms is of high interest. Still, the functional relevance of numerous histone modifications during myogenesis remain completely uncertain. In this study, we focus on the function of H3K36me3 and its epigenetic writer, SET domain containing 2 (SETD2), in the context of muscle cell differentiation. We first observed that SETD2 expression increases during myogenesis. Targeted depletion of SETD2 in undifferentiated (myoblasts) and differentiated (myotubes) muscle cells reduced H3K36me3 levels and induced profound changes in gene expression and slight alterations in alternative splicing, as determined by deep RNA-sequencing analysis. Enzymes that function in metabolic pathways were upregulated in response to SETD2 depletion. Furthermore, we demonstrated that upregulation of several glycolytic enzymes was associated with an increase in intracellular pyruvate levels in SETD2-depleted cells, indicating a novel role for SETD2 in metabolic programming during myogenesis. Together, our results provide new insight into the signalling pathways controlled by chromatin-modifying enzymes and their associated histone modifications during muscle cell differentiation.
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Affiliation(s)
- Hannah J. Wiedner
- Department of Cell Biology and PhysiologyThe University of North Carolina at Chapel HillUSA,Curriculum in Genetics and Molecular Biology (GMB)The University of North Carolina at Chapel HillUSA
| | - Eduardo V. Torres
- Department of Cell Biology and PhysiologyThe University of North Carolina at Chapel HillUSA
| | - R. Eric Blue
- Department of Cell Biology and PhysiologyThe University of North Carolina at Chapel HillUSA
| | - Yi‐Hsuan Tsai
- Lineberger Comprehensive Cancer CenterThe University of North Carolina at Chapel HillUSA
| | - Joel Parker
- Curriculum in Genetics and Molecular Biology (GMB)The University of North Carolina at Chapel HillUSA,Lineberger Comprehensive Cancer CenterThe University of North Carolina at Chapel HillUSA
| | - Jimena Giudice
- Department of Cell Biology and PhysiologyThe University of North Carolina at Chapel HillUSA,Curriculum in Genetics and Molecular Biology (GMB)The University of North Carolina at Chapel HillUSA,McAllister Heart Institute, School of MedicineThe University of North Carolina at Chapel HillUSA
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13
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PARP1′s Involvement in RNA Polymerase II Elongation: Pausing and Releasing Regulation through the Integrator and Super Elongation Complex. Cells 2022; 11:cells11203202. [PMID: 36291070 PMCID: PMC9600911 DOI: 10.3390/cells11203202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/07/2022] [Accepted: 10/08/2022] [Indexed: 11/17/2022] Open
Abstract
RNA polymerase elongation along the gene body is tightly regulated to ensure proper transcription and alternative splicing events. Understanding the mechanism and factors critical in regulating the rate of RNA polymerase II elongation and processivity is clearly important. Recently we showed that PARP1, a well-known DNA repair protein, when bound to chromatin, regulates RNA polymerase II elongation. However, the mechanism by which it does so is not known. In the current study, we aimed to tease out how PARP1 regulates RNAPII elongation. We show, both in vivo and in vitro, that PARP1 binds directly to the Integrator subunit 3 (IntS3), a member of the elongation Integrator complex. The association between the two proteins is mediated via the C-terminal domain of PARP1 to the C-terminal domain of IntS3. Interestingly, the occupancy of IntS3 along two PARP1 target genes mimicked that of PARP1, suggesting a role in its recruitment/assembly of elongation factors. Indeed, the knockdown of PARP1 resulted in differential chromatin association and gene occupancy of IntS3 and other key elongation factors. Most of these PARP1-mediated effects were due to the physical presence of PARP1 rather than its PARylation activity. These studies argue that PARP1 controls the progressive RNAPII elongation complexes. In summary, we present a platform to begin to decipher PARP1′s role in recruiting/scaffolding elongation factors along the gene body regions during RNA polymerase II elongation and gene regulation.
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14
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Imbriano C, Belluti S. Histone Marks-Dependent Effect on Alternative Splicing: New Perspectives for Targeted Splicing Modulation in Cancer? Int J Mol Sci 2022; 23:ijms23158304. [PMID: 35955433 PMCID: PMC9368390 DOI: 10.3390/ijms23158304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
Alternative splicing (AS) is a tightly regulated mechanism that generates the complex human proteome from a small number of genes. Cis-regulatory RNA motifs in exons and introns control AS, recruiting positive and negative trans-acting splicing regulators. At a higher level, chromatin affects splicing events. Growing evidence indicates that the popular histone code hypothesis can be extended to RNA-level processes, such as AS. In addition to nucleosome positioning, which can generate transcriptional barriers to shape the final splicing outcome, histone post-translational modifications can contribute to the detailed regulation of single exon inclusion/exclusion. A histone-based system can identify alternatively spliced chromatin stretches, affecting RNAPII elongation locally or recruiting splicing components via adaptor complexes. In tumor cells, several mechanisms trigger misregulated AS events and produce cancer-associated transcripts. On a genome-wide level, aberrant AS can be the consequence of dysfunctional epigenetic splicing code, including altered enrichment in histone post-translational modifications. This review describes the main findings related to the effect of histone modifications and variants on splicing outcome and how a dysfunctional epigenetic splicing code triggers aberrant AS in cancer. In addition, it highlights recent advances in programmable DNA-targeting technologies and their possible application for AS targeted epigenetic modulation.
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15
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Gnan S, Matelot M, Weiman M, Arnaiz O, Guérin F, Sperling L, Bétermier M, Thermes C, Chen CL, Duharcourt S. GC content, but not nucleosome positioning, directly contributes to intron splicing efficiency in Paramecium. Genome Res 2022; 32:699-709. [PMID: 35264448 PMCID: PMC8997360 DOI: 10.1101/gr.276125.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 02/14/2022] [Indexed: 11/24/2022]
Abstract
Eukaryotic genes are interrupted by introns that must be accurately spliced from mRNA precursors. With an average length of 25 nt, the more than 90,000 introns of Paramecium tetraurelia stand among the shortest introns reported in eukaryotes. The mechanisms specifying the correct recognition of these tiny introns remain poorly understood. Splicing can occur cotranscriptionally, and it has been proposed that chromatin structure might influence splice site recognition. To investigate the roles of nucleosome positioning in intron recognition, we determined the nucleosome occupancy along the P. tetraurelia genome. We show that P. tetraurelia displays a regular nucleosome array with a nucleosome repeat length of ∼151 bp, among the smallest periodicities reported. Our analysis has revealed that introns are frequently associated with inter-nucleosomal DNA, pointing to an evolutionary constraint favoring introns at the AT-rich nucleosome edge sequences. Using accurate splicing efficiency data from cells depleted for nonsense-mediated decay effectors, we show that introns located at the edge of nucleosomes display higher splicing efficiency than those at the center. However, multiple regression analysis indicates that the low GC content of introns, rather than nucleosome positioning, is associated with high splicing efficiency. Our data reveal a complex link between GC content, nucleosome positioning, and intron evolution in Paramecium.
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Affiliation(s)
- Stefano Gnan
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3244, Dynamics of Genetic Information, Paris, 75005 France
| | - Mélody Matelot
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Marion Weiman
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Olivier Arnaiz
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Frédéric Guérin
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Linda Sperling
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Mireille Bétermier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Claude Thermes
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Chun-Long Chen
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3244, Dynamics of Genetic Information, Paris, 75005 France
| | - Sandra Duharcourt
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
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16
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Sergeeva OV, Shcherbinina EY, Shomron N, Zatsepin TS. Modulation of RNA Splicing by Oligonucleotides: Mechanisms of Action and Therapeutic Implications. Nucleic Acid Ther 2022; 32:123-138. [PMID: 35166605 DOI: 10.1089/nat.2021.0067] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dysregulation of RNA splicing causes many diseases and disorders. Several therapeutic approaches have been developed to correct aberrant alternative splicing events for the treatment of cancers and hereditary diseases, including gene therapy and redirecting splicing, using small molecules or splice switching oligonucleotides (SSO). Significant advances in the chemistry and pharmacology of nucleic acid have led to the development of clinically approved SSO drugs for the treatment of spinal muscular dystrophy and Duchenne muscular dystrophy (DMD). In this review, we discuss the mechanisms of SSO action with emphasis on "less common" approaches to modulate alternative splicing, including bipartite and bifunctional SSO, oligonucleotide decoys for splice factors and SSO-mediated mRNA degradation via AS-NMD and NGD pathways. We briefly discuss the current progress and future perspectives of SSO therapy for rare and ultrarare diseases.
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Affiliation(s)
- Olga V Sergeeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | | | - Noam Shomron
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Timofei S Zatsepin
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia.,Department of Chemistry, Moscow State University, Moscow, Russia
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17
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Zhang H, Li S, Cheng Y. Antibiofilm Activity of Allicin and Quercetin in Treating Biofilm-Associated Orthopaedics Infection. Appl Biochem Biotechnol 2022:10.1007/s12010-022-03845-4. [PMID: 35142967 DOI: 10.1007/s12010-022-03845-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2022] [Indexed: 01/09/2023]
Abstract
Biofilms formed by bacteria are the group of sessile microbial cells that remain encompassed by self-secreted polymeric substances and have resulted in great health-care concern. The extracellular polymeric substances (EPS) prevent the penetration of antibiotics and other drugs, thereby resulting in the development of multi-drug resistance or antibiotic resistance. The biofilm-associated prosthetics being places at the joins of bone injury are the common sites for the development of biofilm-associated infection. This often spreads and results in the development of orthopaedic infections. Most of the infections are associated with musculoskeletal system and originate from non-living surfaces. The biofilm prevents the penetration of drugs, thereby resulting in the development of antibiotic resistance or multi-drug resistance. The minimum inhibitory concentration (MIC) for allicin and quercetin was found to be 80 µg/mL for quercetin and 100 µg/mL for amoxicillin against the sessile communities of Pseudomonas aeruginosa associated with the orthopaedic infection. The role of quercetin and allicin in reduction of protein, carbohydrate and eDNA content of the exopolysaccharides (EPS) was tested. The anti-quorum sensing activity of quercetin and allicin was confirmed both by biochemical and by photomicrographic studies. The antibiofilm and antimicrobial activities of quercetin and allicin were determined both by in vitro and in silico studies on P. aeruginosa bacterial strain from biofilm-associated orthopaedic infection.
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Affiliation(s)
- Huajun Zhang
- Department of Orthopaedics, The People's Hospital of Danyang, Affiliated Danyang Hospital of Nantong University, Danyang, 212300, Jiangsu Province, China
| | - Shengjie Li
- The Second Department of Orthopedic, Baiyin Integrated Traditional Chinese and Western Medicine Hospital, Baiyin, 730900, Gansu Province, China
| | - Yujing Cheng
- The First Department of Orthopedic, The First People's Hospital of Taian, Taian, 271000, Shandong Province, China.
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18
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Starks RR, Kaur H, Tuteja G. Mapping cis-regulatory elements in the midgestation mouse placenta. Sci Rep 2021; 11:22331. [PMID: 34785717 PMCID: PMC8595355 DOI: 10.1038/s41598-021-01664-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/01/2021] [Indexed: 12/22/2022] Open
Abstract
The placenta is a temporary organ that provides the developing fetus with nutrients, oxygen, and protection in utero. Defects in its development, which may be caused by misregulated gene expression, can lead to devastating outcomes for the mother and fetus. In mouse, placental defects during midgestation commonly lead to embryonic lethality. However, the regulatory mechanisms controlling expression of genes during this period have not been thoroughly investigated. Therefore, we generated and analyzed ChIP-seq data for multiple histone modifications known to mark cis-regulatory regions. We annotated active and poised promoters and enhancers, as well as regions generally associated with repressed gene expression. We found that poised promoters were associated with neuronal development genes, while active promoters were largely associated with housekeeping genes. Active and poised enhancers were associated with placental development genes, though only active enhancers were associated with genes that have placenta-specific expression. Motif analysis within active enhancers identified a large network of transcription factors, including those that have not been previously studied in the placenta and are candidates for future studies. The data generated and genomic regions annotated provide researchers with a foundation for future studies, aimed at understanding how specific genes in the midgestation mouse placenta are regulated.
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Affiliation(s)
- Rebekah R Starks
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, 50011, USA.,Bioinformatics and Computational Biology, Iowa State University, Ames, IA, 50011, USA
| | - Haninder Kaur
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, 50011, USA
| | - Geetu Tuteja
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, 50011, USA. .,Bioinformatics and Computational Biology, Iowa State University, Ames, IA, 50011, USA.
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19
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Dey P, Mattick JS. High frequency of intron retention and clustered H3K4me3-marked nucleosomes in short first introns of human long non-coding RNAs. Epigenetics Chromatin 2021; 14:45. [PMID: 34579770 PMCID: PMC8477579 DOI: 10.1186/s13072-021-00419-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/27/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND It is established that protein-coding exons are preferentially localized in nucleosomes. To examine whether the same is true for non-coding exons, we analysed nucleosome occupancy in and adjacent to internal exons in genes encoding long non-coding RNAs (lncRNAs) in human CD4+ T cells and K562 cells. RESULTS We confirmed that internal exons in lncRNAs are preferentially associated with nucleosomes, but also observed an elevated signal from H3K4me3-marked nucleosomes in the sequences upstream of these exons. Examination of 200 genomic lncRNA loci chosen at random across all chromosomes showed that high-density regions of H3K4me3-marked nucleosomes, which we term 'slabs', are associated with genomic regions exhibiting intron retention. These retained introns occur in over 50% of lncRNAs examined and are mostly first introns with an average length of just 354 bp, compared to the average length of all human introns of 6355 and 7987 bp in mRNAs and lncRNAs, respectively. Removal of short introns from the dataset abrogated the high upstream H3K4me3 signal, confirming that the association of slabs and short lncRNA introns with intron retention holds genome-wide. The high upstream H3K4me3 signal is also associated with alternatively spliced exons, known to be prominent in lncRNAs. This phenomenon was not observed with mRNAs. CONCLUSIONS There is widespread intron retention and clustered H3K4me3-marked nucleosomes in short first introns of human long non-coding RNAs, which raises intriguing questions about the relationship of IR to lncRNA function and chromatin organization.
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Affiliation(s)
- Pinki Dey
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, 2052, Sydney, Australia
| | - John S Mattick
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, 2052, Sydney, Australia.
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20
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Fang K, Li T, Huang Y, Jin VX. NucHMM: a method for quantitative modeling of nucleosome organization identifying functional nucleosome states distinctly associated with splicing potentiality. Genome Biol 2021; 22:250. [PMID: 34446075 PMCID: PMC8390234 DOI: 10.1186/s13059-021-02465-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 08/12/2021] [Indexed: 01/01/2023] Open
Abstract
We develop a novel computational method, NucHMM, to identify functional nucleosome states associated with cell type-specific combinatorial histone marks and nucleosome organization features such as phasing, spacing and positioning. We test it on publicly available MNase-seq and ChIP-seq data in MCF7, H1, and IMR90 cells and identify 11 distinct functional nucleosome states. We demonstrate these nucleosome states are distinctly associated with the splicing potentiality of skipping exons. This advances our understanding of the chromatin function at the nucleosome level and offers insights into the interplay between nucleosome organization and splicing processes.
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Affiliation(s)
- Kun Fang
- Department of Molecular Medicine, UTHSA-UTSA Joint Biomedical Engineering Program, San Antonio, TX, 78229, USA
| | - Tianbao Li
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Yufei Huang
- Department of Medicine, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, 15232, USA
| | - Victor X Jin
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
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21
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Alharbi AB, Schmitz U, Bailey CG, Rasko JEJ. CTCF as a regulator of alternative splicing: new tricks for an old player. Nucleic Acids Res 2021; 49:7825-7838. [PMID: 34181707 PMCID: PMC8373115 DOI: 10.1093/nar/gkab520] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 06/01/2021] [Accepted: 06/10/2021] [Indexed: 12/15/2022] Open
Abstract
Three decades of research have established the CCCTC-binding factor (CTCF) as a ubiquitously expressed chromatin organizing factor and master regulator of gene expression. A new role for CTCF as a regulator of alternative splicing (AS) has now emerged. CTCF has been directly and indirectly linked to the modulation of AS at the individual transcript and at the transcriptome-wide level. The emerging role of CTCF-mediated regulation of AS involves diverse mechanisms; including transcriptional elongation, DNA methylation, chromatin architecture, histone modifications, and regulation of splicing factor expression and assembly. CTCF thereby appears to not only co-ordinate gene expression regulation but contributes to the modulation of transcriptomic complexity. In this review, we highlight previous discoveries regarding the role of CTCF in AS. In addition, we summarize detailed mechanisms by which CTCF mediates AS regulation. We propose opportunities for further research designed to examine the possible fate of CTCF-mediated alternatively spliced genes and associated biological consequences. CTCF has been widely acknowledged as the 'master weaver of the genome'. Given its multiple connections, further characterization of CTCF's emerging role in splicing regulation might extend its functional repertoire towards a 'conductor of the splicing orchestra'.
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Affiliation(s)
- Adel B Alharbi
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
- Cancer & Gene Regulation Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
| | - Ulf Schmitz
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
| | - Charles G Bailey
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
- Cancer & Gene Regulation Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
| | - John E J Rasko
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
- Cell & Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
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22
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Muniz L, Nicolas E, Trouche D. RNA polymerase II speed: a key player in controlling and adapting transcriptome composition. EMBO J 2021; 40:e105740. [PMID: 34254686 PMCID: PMC8327950 DOI: 10.15252/embj.2020105740] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 05/01/2021] [Accepted: 05/10/2021] [Indexed: 12/19/2022] Open
Abstract
RNA polymerase II (RNA Pol II) speed or elongation rate, i.e., the number of nucleotides synthesized per unit of time, is a major determinant of transcriptome composition. It controls co-transcriptional processes such as splicing, polyadenylation, and transcription termination, thus regulating the production of alternative splice variants, circular RNAs, alternatively polyadenylated transcripts, or read-through transcripts. RNA Pol II speed itself is regulated in response to intra- and extra-cellular stimuli and can in turn affect the transcriptome composition in response to these stimuli. Evidence points to a potentially important role of transcriptome composition modification through RNA Pol II speed regulation for adaptation of cells to a changing environment, thus pointing to a function of RNA Pol II speed regulation in cellular physiology. Analyzing RNA Pol II speed dynamics may therefore be central to fully understand the regulation of physiological processes, such as the development of multicellular organisms. Recent findings also raise the possibility that RNA Pol II speed deregulation can be detrimental and participate in disease progression. Here, we review initial and current approaches to measure RNA Pol II speed, as well as providing an overview of the factors controlling speed and the co-transcriptional processes which are affected. Finally, we discuss the role of RNA Pol II speed regulation in cell physiology.
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Affiliation(s)
- Lisa Muniz
- MCDCentre de Biologie Integrative (CBI)CNRSUPSUniversity of ToulouseToulouseFrance
| | - Estelle Nicolas
- MCDCentre de Biologie Integrative (CBI)CNRSUPSUniversity of ToulouseToulouseFrance
| | - Didier Trouche
- MCDCentre de Biologie Integrative (CBI)CNRSUPSUniversity of ToulouseToulouseFrance
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23
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Zhu G, Guo YA, Ho D, Poon P, Poh ZW, Wong PM, Gan A, Chang MM, Kleftogiannis D, Lau YT, Tay B, Lim WJ, Chua C, Tan TJ, Koo SL, Chong DQ, Yap YS, Tan I, Ng S, Skanderup AJ. Tissue-specific cell-free DNA degradation quantifies circulating tumor DNA burden. Nat Commun 2021; 12:2229. [PMID: 33850132 PMCID: PMC8044092 DOI: 10.1038/s41467-021-22463-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 03/11/2021] [Indexed: 02/08/2023] Open
Abstract
Profiling of circulating tumor DNA (ctDNA) may offer a non-invasive approach to monitor disease progression. Here, we develop a quantitative method, exploiting local tissue-specific cell-free DNA (cfDNA) degradation patterns, that accurately estimates ctDNA burden independent of genomic aberrations. Nucleosome-dependent cfDNA degradation at promoters and first exon-intron junctions is strongly associated with differential transcriptional activity in tumors and blood. A quantitative model, based on just 6 regulatory regions, could accurately predict ctDNA levels in colorectal cancer patients. Strikingly, a model restricted to blood-specific regulatory regions could predict ctDNA levels across both colorectal and breast cancer patients. Using compact targeted sequencing (<25 kb) of predictive regions, we demonstrate how the approach could enable quantitative low-cost tracking of ctDNA dynamics and disease progression. Circulating tumour DNA (ctDNA) represents a non-invasive option to monitor cancer progression. Here, the authors perform deep sequencing of plasma cell-free DNA, and find that nucleosome-dependent cfDNA degradation at 6 specific regulatory regions is predictive of ctDNA burden.
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Affiliation(s)
- Guanhua Zhu
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Yu A Guo
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Danliang Ho
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Polly Poon
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Zhong Wee Poh
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Pui Mun Wong
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Anna Gan
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Mei Mei Chang
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | | | - Yi Ting Lau
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore
| | - Brenda Tay
- National Cancer Center Singapore, Singapore, Singapore
| | - Wan Jun Lim
- National Cancer Center Singapore, Singapore, Singapore
| | - Clarinda Chua
- National Cancer Center Singapore, Singapore, Singapore
| | - Tira J Tan
- National Cancer Center Singapore, Singapore, Singapore
| | - Si-Lin Koo
- National Cancer Center Singapore, Singapore, Singapore
| | - Dawn Q Chong
- National Cancer Center Singapore, Singapore, Singapore
| | - Yoon Sim Yap
- National Cancer Center Singapore, Singapore, Singapore
| | - Iain Tan
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore. .,National Cancer Center Singapore, Singapore, Singapore. .,Duke-NUS Medical School, National University of Singapore, Singapore, Singapore.
| | - Sarah Ng
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore.
| | - Anders J Skanderup
- Genome Institute of Singapore (GIS), A*STAR, Singapore, Singapore. .,National Cancer Center Singapore, Singapore, Singapore.
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24
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Abstract
Methylation at DNA, RNA and protein levels plays critical roles in many cellular processes and is associated with diverse differentiation events, physiological activities and human diseases. To aid in the diagnostic and therapeutic design for cancer treatment utilising methylation, this review provides a boutique yet comprehensive overview on methylation at different levels including the mechanisms, cross-talking and clinical implications with a particular focus on cancers. We conclude that DNA methylation is the sole type of methylation that has been largely translated into clinics and used for, mostly, early diagnosis. Translating the onco-therapeutic and prognostic values of RNA and protein methylations into clinical use deserves intensive efforts. Simultaneous examination of methylations at multiple levels or together with other forms of molecular markers represents an interesting research direction with profound clinical translational potential.
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25
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Role of promoters in regulating alternative splicing. Gene 2021; 782:145523. [PMID: 33667606 DOI: 10.1016/j.gene.2021.145523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/31/2020] [Accepted: 02/09/2021] [Indexed: 01/19/2023]
Abstract
Alternative splicing (AS) plays a critical role in enhancing proteome complexity in higher eukaryotes. Almost all the multi intron-containing genes undergo AS in humans. Splicing mainly occurs co-transcriptionally, where RNA polymerase II (RNA pol II) plays a crucial role in coordinating transcription and pre-mRNA splicing. Aberrant AS leads to non-functional proteins causative in various pathophysiological conditions such as cancers, neurodegenerative diseases, and muscular dystrophies. Transcription and pre-mRNA splicing are deeply interconnected and can influence each other's functions. Several studies evinced that specific promoters employed by RNA pol II dictate the RNA processing decisions. Promoter-specific recruitment of certain transcriptional factors or transcriptional coactivators influences splicing, and the extent to which these factors affect splicing has not been discussed in detail. Here, in this review, various DNA-binding proteins and their influence on promoter-specific AS are extensively discussed. Besides, this review highlights how the promoter-specific epigenetic changes might regulate AS.
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26
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Giles KA, Gould CM, Achinger-Kawecka J, Page SG, Kafer GR, Rogers S, Luu PL, Cesare AJ, Clark SJ, Taberlay PC. BRG1 knockdown inhibits proliferation through multiple cellular pathways in prostate cancer. Clin Epigenetics 2021; 13:37. [PMID: 33596994 PMCID: PMC7888175 DOI: 10.1186/s13148-021-01023-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 02/04/2021] [Indexed: 12/13/2022] Open
Abstract
Background BRG1 (encoded by SMARCA4) is a catalytic component of the SWI/SNF chromatin remodelling complex, with key roles in modulating DNA accessibility. Dysregulation of BRG1 is observed, but functionally uncharacterised, in a wide range of malignancies. We have probed the functions of BRG1 on a background of prostate cancer to investigate how BRG1 controls gene expression programmes and cancer cell behaviour. Results Our investigation of SMARCA4 revealed that BRG1 is over-expressed in the majority of the 486 tumours from The Cancer Genome Atlas prostate cohort, as well as in a complementary panel of 21 prostate cell lines. Next, we utilised a temporal model of BRG1 depletion to investigate the molecular effects on global transcription programmes. Depleting BRG1 had no impact on alternative splicing and conferred only modest effect on global expression. However, of the transcriptional changes that occurred, most manifested as down-regulated expression. Deeper examination found the common thread linking down-regulated genes was involvement in proliferation, including several known to increase prostate cancer proliferation (KLK2, PCAT1 and VAV3). Interestingly, the promoters of genes driving proliferation were bound by BRG1 as well as the transcription factors, AR and FOXA1. We also noted that BRG1 depletion repressed genes involved in cell cycle progression and DNA replication, but intriguingly, these pathways operated independently of AR and FOXA1. In agreement with transcriptional changes, depleting BRG1 conferred G1 arrest. Conclusions Our data have revealed that BRG1 promotes cell cycle progression and DNA replication, consistent with the increased cell proliferation associated with oncogenesis. Supplementary Information The online version contains supplementary material available at 10.1186/s13148-021-01023-7.
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Affiliation(s)
- Katherine A Giles
- Epigenetics Laboratory, Genomics and Epigenetics Theme, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia.,Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW, 2145, Australia.,Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, TAS, Hobart, 7000, Australia
| | - Cathryn M Gould
- Epigenetics Laboratory, Genomics and Epigenetics Theme, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Joanna Achinger-Kawecka
- Epigenetics Laboratory, Genomics and Epigenetics Theme, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, 2000, Australia
| | - Scott G Page
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW, 2145, Australia
| | - Georgia R Kafer
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW, 2145, Australia
| | - Samuel Rogers
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW, 2145, Australia
| | - Phuc-Loi Luu
- Epigenetics Laboratory, Genomics and Epigenetics Theme, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, 2000, Australia
| | - Anthony J Cesare
- Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW, 2145, Australia
| | - Susan J Clark
- Epigenetics Laboratory, Genomics and Epigenetics Theme, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia.,St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, 2000, Australia
| | - Phillippa C Taberlay
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, TAS, Hobart, 7000, Australia.
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27
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Angarola BL, Anczuków O. Splicing alterations in healthy aging and disease. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021. [PMID: 33565261 DOI: 10.1002/wrna.1643.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alternative RNA splicing is a key step in gene expression that allows generation of numerous messenger RNA transcripts encoding proteins of varied functions from the same gene. It is thus a rich source of proteomic and functional diversity. Alterations in alternative RNA splicing are observed both during healthy aging and in a number of human diseases, several of which display premature aging phenotypes or increased incidence with age. Age-associated splicing alterations include differential splicing of genes associated with hallmarks of aging, as well as changes in the levels of core spliceosomal genes and regulatory splicing factors. Here, we review the current known links between alternative RNA splicing, its regulators, healthy biological aging, and diseases associated with aging or aging-like phenotypes. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
| | - Olga Anczuków
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA.,Department of Genetics and Genome Sciences, UConn Health, Farmington, Connecticut, USA.,Institute for Systems Genomics, UConn Health, Farmington, Connecticut, USA
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28
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Angarola BL, Anczuków O. Splicing alterations in healthy aging and disease. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1643. [PMID: 33565261 DOI: 10.1002/wrna.1643] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/19/2022]
Abstract
Alternative RNA splicing is a key step in gene expression that allows generation of numerous messenger RNA transcripts encoding proteins of varied functions from the same gene. It is thus a rich source of proteomic and functional diversity. Alterations in alternative RNA splicing are observed both during healthy aging and in a number of human diseases, several of which display premature aging phenotypes or increased incidence with age. Age-associated splicing alterations include differential splicing of genes associated with hallmarks of aging, as well as changes in the levels of core spliceosomal genes and regulatory splicing factors. Here, we review the current known links between alternative RNA splicing, its regulators, healthy biological aging, and diseases associated with aging or aging-like phenotypes. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
| | - Olga Anczuków
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA.,Department of Genetics and Genome Sciences, UConn Health, Farmington, Connecticut, USA.,Institute for Systems Genomics, UConn Health, Farmington, Connecticut, USA
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29
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Agirre E, Oldfield AJ, Bellora N, Segelle A, Luco RF. Splicing-associated chromatin signatures: a combinatorial and position-dependent role for histone marks in splicing definition. Nat Commun 2021; 12:682. [PMID: 33514745 PMCID: PMC7846797 DOI: 10.1038/s41467-021-20979-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/05/2021] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing relies on the combinatorial recruitment of splicing regulators to specific RNA binding sites. Chromatin has been shown to impact this recruitment. However, a limited number of histone marks have been studied at a global level. In this work, a machine learning approach, applied to extensive epigenomics datasets in human H1 embryonic stem cells and IMR90 foetal fibroblasts, has identified eleven chromatin modifications that differentially mark alternatively spliced exons depending on the level of exon inclusion. These marks act in a combinatorial and position-dependent way, creating characteristic splicing-associated chromatin signatures (SACS). In support of a functional role for SACS in coordinating splicing regulation, changes in the alternative splicing of SACS-marked exons between ten different cell lines correlate with changes in SACS enrichment levels and recruitment of the splicing regulators predicted by RNA motif search analysis. We propose the dynamic nature of chromatin modifications as a mechanism to rapidly fine-tune alternative splicing when necessary. Chromatin is known to regulate splicing by modulating recruitment of splicing factors. Using machine learning approaches, the authors have underlined a chromatin code for alternative splicing regulation that is conserved amongst cell lines.
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Affiliation(s)
- E Agirre
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34000, Montpellier, France.,Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - A J Oldfield
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34000, Montpellier, France
| | - N Bellora
- Institute of Nuclear Technologies for Health (INTECNUS), National Scientific and Technical Research Council (CONICET), Bariloche, 8400, Argentina
| | - A Segelle
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34000, Montpellier, France
| | - R F Luco
- Institute of Human Genetics, UMR9002 CNRS-University of Montpellier, 34000, Montpellier, France.
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30
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Petasny M, Bentata M, Pawellek A, Baker M, Kay G, Salton M. Splicing to Keep Cycling: The Importance of Pre-mRNA Splicing during the Cell Cycle. Trends Genet 2020; 37:266-278. [PMID: 32950269 DOI: 10.1016/j.tig.2020.08.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/09/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022]
Abstract
Pre-mRNA splicing is a fundamental process in mammalian gene expression, and alternative splicing plays an extensive role in generating protein diversity. Because the majority of genes undergo pre-mRNA splicing, most cellular processes depend on proper spliceosome function. We focus on the cell cycle and describe its dependence on pre-mRNA splicing and accurate alternative splicing. We outline the key cell-cycle factors and their known alternative splicing isoforms. We discuss different levels of pre-mRNA splicing regulation such as post-translational modifications and changes in the expression of splicing factors. We describe the effect of chromatin dynamics on pre-mRNA splicing during the cell cycle. In addition, we focus on spliceosome component SF3B1, which is mutated in many types of cancer, and describe the link between SF3B1 and its inhibitors and the cell cycle.
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Affiliation(s)
- Mayra Petasny
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mercedes Bentata
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Andrea Pawellek
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Mai Baker
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Gillian Kay
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Maayan Salton
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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31
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Chen JB, Dong SS, Yao S, Duan YY, Hu WX, Chen H, Wang NN, Chen XF, Hao RH, Thynn HN, Guo MR, Zhang YJ, Rong Y, Chen YX, Zhou FL, Guo Y, Yang TL. Modeling circRNA expression pattern with integrated sequence and epigenetic features demonstrates the potential involvement of H3K79me2 in circRNA expression. Bioinformatics 2020; 36:4739-4748. [PMID: 32539144 DOI: 10.1093/bioinformatics/btaa567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 05/07/2020] [Accepted: 06/08/2020] [Indexed: 01/22/2023] Open
Abstract
MOTIVATION CircRNAs are an abundant class of non-coding RNAs with widespread, cell-/tissue-specific patterns. Previous work suggested that epigenetic features might be related to circRNA expression. However, the contribution of epigenetic changes to circRNA expression has not been investigated systematically. Here, we built a machine learning framework named CIRCScan, to predict circRNA expression in various cell lines based on the sequence and epigenetic features. RESULTS The predicted accuracy of the expression status models was high with area under the curve of receiver operating characteristic (ROC) values of 0.89-0.92 and the false-positive rates of 0.17-0.25. Predicted expressed circRNAs were further validated by RNA-seq data. The performance of expression-level prediction models was also good with normalized root-mean-square errors of 0.28-0.30 and Pearson's correlation coefficient r over 0.4 in all cell lines, along with Spearman's correlation coefficient ρ of 0.33-0.46. Noteworthy, H3K79me2 was highly ranked in modeling both circRNA expression status and levels across different cells. Further analysis in additional nine cell lines demonstrated a significant enrichment of H3K79me2 in circRNA flanking intron regions, supporting the potential involvement of H3K79me2 in circRNA expression regulation. AVAILABILITY AND IMPLEMENTATION The CIRCScan assembler is freely available online for academic use at https://github.com/johnlcd/CIRCScan. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Jia-Bin Chen
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Shan-Shan Dong
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Shi Yao
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Yuan-Yuan Duan
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Wei-Xin Hu
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Hao Chen
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Nai-Ning Wang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Xiao-Feng Chen
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Ruo-Han Hao
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Hlaing Nwe Thynn
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Ming-Rui Guo
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Yu-Jie Zhang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Yu Rong
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Yi-Xiao Chen
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Fu-Ling Zhou
- Department of Hematopathology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Yan Guo
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Tie-Lin Yang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
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32
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Tellier M, Maudlin I, Murphy S. Transcription and splicing: A two-way street. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1593. [PMID: 32128990 DOI: 10.1002/wrna.1593] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/18/2019] [Accepted: 02/12/2020] [Indexed: 12/11/2022]
Abstract
RNA synthesis by RNA polymerase II and RNA processing are closely coupled during the transcription cycle of protein-coding genes. This coupling affords opportunities for quality control and regulation of gene expression and the effects can go in both directions. For example, polymerase speed can affect splice site selection and splicing can increase transcription and affect the chromatin landscape. Here we review the many ways that transcription and splicing influence one another, including how splicing "talks back" to transcription. We will also place the connections between transcription and splicing in the context of other RNA processing events that define the exons that will make up the final mRNA. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Michael Tellier
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Isabella Maudlin
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Shona Murphy
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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33
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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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34
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Lee D, Zhang J, Liu J, Gerstein M. Epigenome-based splicing prediction using a recurrent neural network. PLoS Comput Biol 2020; 16:e1008006. [PMID: 32584815 PMCID: PMC7343189 DOI: 10.1371/journal.pcbi.1008006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/08/2020] [Accepted: 06/01/2020] [Indexed: 12/16/2022] Open
Abstract
Alternative RNA splicing provides an important means to expand metazoan transcriptome diversity. Contrary to what was accepted previously, splicing is now thought to predominantly take place during transcription. Motivated by emerging data showing the physical proximity of the spliceosome to Pol II, we surveyed the effect of epigenetic context on co-transcriptional splicing. In particular, we observed that splicing factors were not necessarily enriched at exon junctions and that most epigenetic signatures had a distinctly asymmetric profile around known splice sites. Given this, we tried to build an interpretable model that mimics the physical layout of splicing regulation where the chromatin context progressively changes as the Pol II moves along the guide DNA. We used a recurrent-neural-network architecture to predict the inclusion of a spliced exon based on adjacent epigenetic signals, and we showed that distinct spatio-temporal features of these signals were key determinants of model outcome, in addition to the actual nucleotide sequence of the guide DNA strand. After the model had been trained and tested (with >80% precision-recall curve metric), we explored the derived weights of the latent factors, finding they highlight the importance of the asymmetric time-direction of chromatin context during transcription.
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Affiliation(s)
- Donghoon Lee
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Jing Zhang
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Jason Liu
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Mark Gerstein
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Computer Science, Yale University, New Haven, Connecticut, United States of America
- Department of Statistics and Data Science, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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35
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The DNA methylation landscape in cancer. Essays Biochem 2020; 63:797-811. [PMID: 31845735 PMCID: PMC6923322 DOI: 10.1042/ebc20190037] [Citation(s) in RCA: 163] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 12/13/2022]
Abstract
As one of the most abundant and well-studied epigenetic modifications, DNA methylation plays an essential role in normal development and cellular biology. Global alterations to the DNA methylation landscape contribute to alterations in the transcriptome and deregulation of cellular pathways. Indeed, improved methods to study DNA methylation patterning and dynamics at base pair resolution and across individual DNA molecules on a genome-wide scale has highlighted the scope of change to the DNA methylation landscape in disease states, particularly during tumorigenesis. More recently has been the development of DNA hydroxymethylation profiling techniques, which allows differentiation between 5mC and 5hmC profiles and provides further insights into DNA methylation dynamics and remodeling in tumorigenesis. In this review, we describe the distribution of DNA methylation and DNA hydroxymethylation in different genomic contexts, first in normal cells, and how this is altered in cancer. Finally, we discuss DNA methylation profiling technologies and the most recent advances in single-cell methods, bisulfite-free approaches and ultra-long read sequencing techniques.
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36
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Kindgren P, Ivanov M, Marquardt S. Native elongation transcript sequencing reveals temperature dependent dynamics of nascent RNAPII transcription in Arabidopsis. Nucleic Acids Res 2020; 48:2332-2347. [PMID: 31863587 PMCID: PMC7049701 DOI: 10.1093/nar/gkz1189] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 12/05/2019] [Accepted: 12/11/2019] [Indexed: 01/12/2023] Open
Abstract
Temperature profoundly affects the kinetics of biochemical reactions, yet how large molecular complexes such as the transcription machinery accommodate changing temperatures to maintain cellular function is poorly understood. Here, we developed plant native elongating transcripts sequencing (plaNET-seq) to profile genome-wide nascent RNA polymerase II (RNAPII) transcription during the cold-response of Arabidopsis thaliana with single-nucleotide resolution. Combined with temporal resolution, these data revealed transient genome-wide reprogramming of nascent RNAPII transcription during cold, including characteristics of RNAPII elongation and thousands of non-coding transcripts connected to gene expression. Our results suggest a role for promoter-proximal RNAPII stalling in predisposing genes for transcriptional activation during plant-environment interactions. At gene 3'-ends, cold initially facilitated transcriptional termination by limiting the distance of read-through transcription. Within gene bodies, cold reduced the kinetics of co-transcriptional splicing leading to increased intragenic stalling. Our data resolved multiple distinct mechanisms by which temperature transiently altered the dynamics of nascent RNAPII transcription and associated RNA processing, illustrating potential biotechnological solutions and future focus areas to promote food security in the context of a changing climate.
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Affiliation(s)
- Peter Kindgren
- University of Copenhagen, Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, Frederiksberg, Denmark
| | - Maxim Ivanov
- University of Copenhagen, Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, Frederiksberg, Denmark
| | - Sebastian Marquardt
- University of Copenhagen, Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, Frederiksberg, Denmark
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37
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Park B, Khanam R, Vinayachandran V, Baqui AH, London SJ, Biswal S. Epigenetic biomarkers and preterm birth. ENVIRONMENTAL EPIGENETICS 2020; 6:dvaa005. [PMID: 32551139 PMCID: PMC7293830 DOI: 10.1093/eep/dvaa005] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 05/06/2023]
Abstract
Preterm birth (PTB) is a major public health challenge, and novel, sensitive approaches to predict PTB are still evolving. Epigenomic markers are being explored as biomarkers of PTB because of their molecular stability compared to gene expression. This approach is also relatively new compared to gene-based diagnostics, which relies on mutations or single nucleotide polymorphisms. The fundamental principle of epigenome diagnostics is that epigenetic reprogramming in the target tissue (e.g. placental tissue) might be captured by more accessible surrogate tissue (e.g. blood) using biochemical epigenome assays on circulating DNA that incorporate methylation, histone modifications, nucleosome positioning, and/or chromatin accessibility. Epigenomic-based biomarkers may hold great potential for early identification of the majority of PTBs that are not associated with genetic variants or mutations. In this review, we discuss recent advances made in the development of epigenome assays focusing on its potential exploration for association and prediction of PTB. We also summarize population-level cohort studies conducted in the USA and globally that provide opportunities for genetic and epigenetic marker development for PTB. In addition, we summarize publicly available epigenome resources and published PTB studies. We particularly focus on ongoing genome-wide DNA methylation and epigenome-wide association studies. Finally, we review the limitations of current research, the importance of establishing a comprehensive biobank, and possible directions for future studies in identifying effective epigenome biomarkers to enhance health outcomes for pregnant women at risk of PTB and their infants.
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Affiliation(s)
- Bongsoo Park
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Rasheda Khanam
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, International Center for Maternal and Newborn Health, Baltimore, MD 21205, USA
| | - Vinesh Vinayachandran
- School of Medicine, Cardiovascular Research Institute, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Abdullah H Baqui
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, International Center for Maternal and Newborn Health, Baltimore, MD 21205, USA
| | - Stephanie J London
- Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Shyam Biswal
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Wissink EM, Vihervaara A, Tippens ND, Lis JT. Nascent RNA analyses: tracking transcription and its regulation. Nat Rev Genet 2019; 20:705-723. [PMID: 31399713 PMCID: PMC6858503 DOI: 10.1038/s41576-019-0159-6] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2019] [Indexed: 12/19/2022]
Abstract
The programmes that direct an organism's development and maintenance are encoded in its genome. Decoding of this information begins with regulated transcription of genomic DNA into RNA. Although transcription and its control can be tracked indirectly by measuring stable RNAs, it is only by directly measuring nascent RNAs that the immediate regulatory changes in response to developmental, environmental, disease and metabolic signals are revealed. Multiple complementary methods have been developed to quantitatively track nascent transcription genome-wide at nucleotide resolution, all of which have contributed novel insights into the mechanisms of gene regulation and transcription-coupled RNA processing. Here we critically evaluate the array of strategies used for investigating nascent transcription and discuss the recent conceptual advances they have provided.
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Affiliation(s)
- Erin M Wissink
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Anniina Vihervaara
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Nathaniel D Tippens
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Tri-Institutional Training Program in Computational Biology and Medicine, New York, NY, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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Glaich O, Leader Y, Lev Maor G, Ast G. Histone H1.5 binds over splice sites in chromatin and regulates alternative splicing. Nucleic Acids Res 2019; 47:6145-6159. [PMID: 31076740 PMCID: PMC6614845 DOI: 10.1093/nar/gkz338] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 04/17/2019] [Accepted: 04/27/2019] [Indexed: 12/11/2022] Open
Abstract
Chromatin organization and epigenetic markers influence splicing, though the magnitudes of these effects and the mechanisms are largely unknown. Here, we demonstrate that linker histone H1.5 influences mRNA splicing. We observed that linker histone H1.5 binds DNA over splice sites of short exons in human lung fibroblasts (IMR90 cells). We found that association of H1.5 with these splice sites correlated with the level of inclusion of alternatively spliced exons. Exons marked by H1.5 had more RNA polymerase II (RNAP II) stalling near the 3' splice site than did exons not associated with H1.5. In cells depleted of H1.5, we showed that the inclusion of five exons evaluated decreased and that RNAP II levels over these exons were also reduced. Our findings indicate that H1.5 is involved in regulation of splice site selection and alternative splicing, a function not previously demonstrated for linker histones.
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Affiliation(s)
- Ohad Glaich
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Yodfat Leader
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Galit Lev Maor
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Gil Ast
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
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LMX1B mRNA expression and its gene body CpG methylation are valuable prognostic biomarkers for laryngeal squamous cell carcinoma. Biomed Pharmacother 2019; 117:109174. [PMID: 31387183 DOI: 10.1016/j.biopha.2019.109174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/15/2019] [Accepted: 06/25/2019] [Indexed: 01/07/2023] Open
Abstract
This study aimed to explore the prognostic value of LMX1B mRNA expression and the methylation of its CpG sites in patients with laryngeal squamous cell carcinoma (LSCC). An in-silicon analysis was performed using data from the cancer genome atlas (TCGA)-Head and Neck Squamous Carcinoma (HNSC). After screening, 112 LSCC and 10 adjacent normal tissues were identified as eligible samples for analysis. Results showed that LMX1B expression was significantly upregulated in the cancer tissues (p < 0.01) and was an independent prognostic indicator in terms of OS (HR: 1.233, 95%CI: 1.082-1.405, p = 0.002) and RFS (HR: 1.200, 95%CI: 1.002-1.438, p = 0.048). By examining the methylation profile of 55 CpG sites in LMX1B locus, we found that the promoter methylation status was irrelevant to LMX1B expression. In comparison, LMX1B expression was generally positively correlated with gene body methylation. Among the gene body CpG sites, cg13600622 methylation showed a better predictive value than LMX1B expression in terms of OS (HR: 12.363, 95%CI: 1.076-142.033, p = 0.043), while cg14204784 methylation was a better marker of shorter RFS (HR: 12.363, 95%CI: 1.076-142.033, p = 0.043). Among the known downstream genes of LMX1B, only NR4A2 expression showed a moderately negative correlation (Pearson's r = -0.54) with it in LSCC tissues. However, this correlation was inconsistent with previous publications those reported a positive correlation between them. Based on these findings, we infer that upregulated LMX1B mRNA expression had an independent prognostic value in LSCC patients. Increased gene body methylation might be an important mechanism of its upregulation. Among the gene body CpG sites, cg13600622 and cg14204784 methylation level might be better prognostic markers than LMX1B mRNA expression in terms of OS and RFS respectively.
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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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van Heesbeen HJ, Smidt MP. Entanglement of Genetics and Epigenetics in Parkinson's Disease. Front Neurosci 2019; 13:277. [PMID: 30983962 PMCID: PMC6449477 DOI: 10.3389/fnins.2019.00277] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 03/08/2019] [Indexed: 01/01/2023] Open
Abstract
Parkinson disease (PD) is a common neurodegenerative disorder that progresses with age, with an increasing number of symptoms. Some of the efforts to understand PD progression have been focusing on the regulation of epigenetic mechanisms, that generally include small molecular modifications to the DNA and histones that are essential for regulating gene activity. Here, we have pointed out difficulties to untangle genetic and epigenetic mechanisms, and reviewed several studies that have aimed for untangling. Some of those have enabled more solid claims on independent roles for epigenetic mechanisms. Hereby, evidence that specific DNA hydroxymethylation, global hyperacetylation, and histone deacetylase (HDAC) dependent regulation of SNCA, one of the hallmark genes involved in PD, have become more prominent from the current perspective, than mechanisms that directly involve DNA methylation. In the absence of current epigenetic clinical targets to counteract PD progression, we also hypothesize how several mechanisms may affect local and global epigenetics in PD neurons, including inflammation, oxidative stress, autophagy and DNA repair mechanisms which may lead to future therapeutic targets.
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Affiliation(s)
| | - Marten P. Smidt
- Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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43
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Ragan C, Goodall GJ, Shirokikh NE, Preiss T. Insights into the biogenesis and potential functions of exonic circular RNA. Sci Rep 2019; 9:2048. [PMID: 30765711 PMCID: PMC6376117 DOI: 10.1038/s41598-018-37037-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 12/03/2018] [Indexed: 01/16/2023] Open
Abstract
Circular RNAs (circRNAs) exhibit unique properties due to their covalently closed nature. Models of circRNAs synthesis and function are emerging but much remains undefined about this surprisingly prevalent class of RNA. Here, we identified exonic circRNAs from human and mouse RNA-sequencing datasets, documenting multiple new examples. Addressing function, we found that many circRNAs co-sediment with ribosomes, indicative of their translation potential. By contrast, circRNAs with potential to act as microRNA sponges were scarce, with some support for a collective sponge function by groups of circRNAs. Addressing circRNA biogenesis, we delineated several features commonly associated with circRNA occurrence. CircRNA-producing genes tend to be longer and to contain more exons than average. Back-splice acceptor exons are strongly enriched at ordinal position 2 within genes, and circRNAs typically have a short exon span with two exons being the most prevalent. The flanking introns either side of circRNA loci are exceptionally long. Of note also, single-exon circRNAs derive from unusually long exons while multi-exon circRNAs are mostly generated from exons of regular length. These findings independently validate and extend similar observations made in a number of prior studies. Furthermore, we analysed high-resolution RNA polymerase II occupancy data from two separate human cell lines to reveal distinctive transcription dynamics at circRNA-producing genes. Specifically, RNA polymerase II traverses the introns of these genes at above average speed concomitant with an accentuated slow-down at exons. Collectively, these features indicate how a perturbed balance between transcription and linear splicing creates important preconditions for circRNA production. We speculate that these preconditions need to be in place so that looping interactions between flanking introns can promote back-splicing to raise circRNA production to appreciable levels.
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Affiliation(s)
- Chikako Ragan
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, 5000, Australia
- Discipline of Medicine, The University of Adelaide, Adelaide, SA, 5005, Australia
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Nikolay E Shirokikh
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
| | - Thomas Preiss
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia.
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Yu X, Meng X, Liu Y, Wang X, Wang TJ, Zhang A, Li N, Qi X, Liu B, Xu ZY. The chromatin remodeler ZmCHB101 impacts alternative splicing contexts in response to osmotic stress. PLANT CELL REPORTS 2019; 38:131-145. [PMID: 30443733 DOI: 10.1007/s00299-018-2354-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 11/07/2018] [Indexed: 05/16/2023]
Abstract
Maize SWI3-type chromatin remodeler impacts alternative splicing contexts in response to osmotic stress by altering nucleosome density and affecting transcriptional elongation rate. Alternative splicing (AS) is commonly found in higher eukaryotes and is an important posttranscriptional regulatory mechanism to generate transcript diversity. AS has been widely accepted as playing essential roles in different biological processes including growth, development, signal transduction and responses to biotic and abiotic stresses in plants. However, whether and how chromatin remodeling complex functions in AS in plant under osmotic stress remains unknown. Here, we show that a maize SWI3D protein, ZmCHB101, impacts AS contexts in response to osmotic stress. Genome-wide analysis of mRNA contexts in response to osmotic stress using ZmCHB101-RNAi lines reveals that ZmCHB101 impacts alternative splicing contexts of a subset of osmotic stress-responsive genes. Intriguingly, ZmCHB101-mediated regulation of gene expression and AS is largely uncoupled, pointing to diverse molecular functions of ZmCHB101 in transcriptional and posttranscriptional regulation. We further found ZmCHB101 impacts the alternative splicing contexts by influencing alteration of chromatin and histone modification status as well as transcriptional elongation rates mediated by RNA polymerase II. Taken together, our findings suggest a novel insight of how plant chromatin remodeling complex impacts AS under osmotic stress .
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Affiliation(s)
- Xiaoming Yu
- School of Agronomy, Jilin Agricultural Science and Technology University, Jilin, 132301, People's Republic of China
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Xinchao Meng
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Yutong Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Xutong Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China
- Department of Agronomy, Purdue University, West Lafayette, USA
| | - Tian-Jing Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Ai Zhang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Ning Li
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Xin Qi
- Department of Agronomy, Jilin Agricultural University, Changchun, 130118, People's Republic of China
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China.
| | - Zheng-Yi Xu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, People's Republic of China.
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The Role of Nucleosomes in Epigenetic Gene Regulation. Clin Epigenetics 2019. [DOI: 10.1007/978-981-13-8958-0_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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46
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De S, Cheng Y, Sun MA, Gehred ND, Kassis JA. Structure and function of an ectopic Polycomb chromatin domain. SCIENCE ADVANCES 2019; 5:eaau9739. [PMID: 30662949 PMCID: PMC6326746 DOI: 10.1126/sciadv.aau9739] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/28/2018] [Indexed: 05/14/2023]
Abstract
Polycomb group proteins (PcGs) drive target gene repression and form large chromatin domains. In Drosophila, DNA elements known as Polycomb group response elements (PREs) recruit PcGs to the DNA. We have shown that, within the invected-engrailed (inv-en) Polycomb domain, strong, constitutive PREs are dispensable for Polycomb domain structure and function. We suggest that the endogenous chromosomal location imparts stability to this Polycomb domain. To test this possibility, a 79-kb en transgene was inserted into other chromosomal locations. This transgene is functional and forms a Polycomb domain. The spreading of the H3K27me3 repressive mark, characteristic of PcG domains, varies depending on the chromatin context of the transgene. Unlike at the endogenous locus, deletion of the strong, constitutive PREs from the transgene leads to both loss- and gain-of function phenotypes, demonstrating the important role of these regulatory elements. Our data show that chromatin context plays an important role in Polycomb domain structure and function.
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Abstract
Nucleosomal modifications have been implicated in fundamental epigenetic regulation, whereas the roles of nucleosome binding in shaping changes through evolution remain to be addressed. Here we performed a comparative study to clarify the roles of nucleosome occupancy in exon origination. By profiling a high-resolution, cross-species mononucleosome landscape for mammalian tissues, we found nucleosome occupancy profiles are conserved across tissues and species. Further, through a phylogenetic approach, we found that the feature of differential nucleosome occupancy appears prior to the origination of new exons and, presumably, facilitates the origin of new exons by increasing the splice strength of the ancestral nonexonic regions through driving a local difference in GC content, which suggests the function of nucleosome binding in exonization. Nucleosomal modifications have been implicated in fundamental epigenetic regulation, but the roles of nucleosome occupancy in shaping changes through evolution remain to be addressed. Here we present high-resolution nucleosome occupancy profiles for multiple tissues derived from human, macaque, tree shrew, mouse, and pig. Genome-wide comparison reveals conserved nucleosome occupancy profiles across both different species and tissue types. Notably, we found significantly higher levels of nucleosome occupancy in exons than in introns, a pattern correlated with the different exon–intron GC content. We then determined whether this biased occupancy may play roles in the origination of new exons through evolution, rather than being a downstream effect of exonization, through a comparative approach to sequentially trace the order of the exonization and biased nucleosome binding. By identifying recently evolved exons in human but not in macaque using matched RNA sequencing, we found that higher exonic nucleosome occupancy also existed in macaque regions orthologous to these exons. Presumably, such biased nucleosome occupancy facilitates the origination of new exons by increasing the splice strength of the ancestral nonexonic regions through driving a local difference in GC content. These data thus support a model that sites bound by nucleosomes are more likely to evolve into exons, which we term the “nucleosome-first” model.
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Cheng X, Hou Y, Nie Y, Zhang Y, Huang H, Liu H, Sun X. Nucleosome Positioning of Intronless Genes in the Human Genome. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2018; 15:1111-1121. [PMID: 26415210 DOI: 10.1109/tcbb.2015.2476811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nucleosomes, the basic units of chromatin, are involved in transcription regulation and DNA replication. Intronless genes, which constitute 3 percent of the human genome, differ from intron-containing genes in evolution and function. Our analysis reveals that nucleosome positioning shows a distinct pattern in intronless and intron-containing genes. The nucleosome occupancy upstream of transcription start sites of intronless genes is lower than that of intron-containing genes. In contrast, high occupancy and well positioned nucleosomes are observed along the gene body of intronless genes, which is perfectly consistent with the barrier nucleosome model. Intronless genes have a significantly lower expression level than intron-containing genes and most of them are not expressed in CD4+ T cell lines and GM12878 cell lines, which results from their tissue specificity. However, the highly expressed genes are at the same expression level between the two types of genes. The highly expressed intronless genes require a higher density of RNA Pol II in an elongating state to compensate for the lack of introns. Additionally, 5' and 3' nucleosome depleted regions of highly expressed intronless genes are deeper than those of highly expressed intron-containing genes.
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49
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Li T, Liu Q, Garza N, Kornblau S, Jin VX. Integrative analysis reveals functional and regulatory roles of H3K79me2 in mediating alternative splicing. Genome Med 2018; 10:30. [PMID: 29665865 PMCID: PMC5902843 DOI: 10.1186/s13073-018-0538-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/29/2018] [Indexed: 01/26/2023] Open
Abstract
Background Accumulating evidence suggests alternative splicing (AS) is a co-transcriptional splicing process not only controlled by RNA-binding splicing factors, but also mediated by epigenetic regulators, such as chromatin structure, nucleosome density, and histone modification. Aberrant AS plays an important role in regulating various diseases, including cancers. Methods In this study, we integrated AS events derived from RNA-seq with H3K79me2 ChIP-seq data across 34 different normal and cancer cell types and found the higher enrichment of H3K79me2 in two AS types, skipping exon (SE) and alternative 3′ splice site (A3SS). Results Interestingly, by applying self-organizing map (SOM) clustering, we unveiled two clusters mainly comprised of blood cancer cell types with a strong correlation between H3K79me2 and SE. Remarkably, the expression of transcripts associated with SE was not significantly different from that of those not associated with SE, indicating the involvement of H3K79me2 in splicing has little impact on full mRNA transcription. We further showed that the deletion of DOT1L1, the sole H3K79 methyltransferase, impeded leukemia cell proliferation as well as switched exon skipping to the inclusion isoform in two MLL-rearranged acute myeloid leukemia cell lines. Our data demonstrate H3K79me2 was involved in mediating SE processing, which might in turn influence transformation and disease progression in leukemias. Conclusions Collectively, our work for the first time reveals that H3K79me2 plays functional and regulatory roles through a co-transcriptional splicing mechanism. Electronic supplementary material The online version of this article (10.1186/s13073-018-0538-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tianbao Li
- College of Life Science, Jilin University, Changchun, 130012, China.,Department of Molecular Medicine, University of Texas Health, 8403 Floyd Curl, San Antonio, TX, 78229, USA
| | - Qi Liu
- Department of Molecular Medicine, University of Texas Health, 8403 Floyd Curl, San Antonio, TX, 78229, USA
| | - Nick Garza
- Department of Molecular Medicine, University of Texas Health, 8403 Floyd Curl, San Antonio, TX, 78229, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Steven Kornblau
- Department of Leukemia, UT MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Victor X Jin
- Department of Molecular Medicine, University of Texas Health, 8403 Floyd Curl, San Antonio, TX, 78229, USA.
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50
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Kim YE, Park C, Kim KE, Kim KK. Histone and RNA-binding protein interaction creates crosstalk network for regulation of alternative splicing. Biochem Biophys Res Commun 2018; 499:30-36. [PMID: 29551686 DOI: 10.1016/j.bbrc.2018.03.101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 03/13/2018] [Indexed: 12/18/2022]
Abstract
Alternative splicing is an essential process in eukaryotes, as it increases the complexity of gene expression by generating multiple proteins from a single pre-mRNA. However, information on the regulatory mechanisms for alternative splicing is lacking, because splicing occurs over a short period via the transient interactions of proteins within functional complexes of the spliceosome. Here, we investigated in detail the molecular mechanisms connecting alternative splicing with epigenetic mechanisms. We identified interactions between histone proteins and splicing factors such as Rbfox2, Rbfox3, and splicing factor proline and glutamine rich protein (SFPQ) by in vivo crosslinking and immunoprecipitation. Furthermore, we confirmed that splicing factors were bound to specific modified residues of histone proteins. Additionally, changes in histone methylation due to histone methyltransferase inhibitor treatment notably affected alternative splicing in selected genes. Therefore, we suggested that there may be crosstalk mechanisms connecting histone modifications and RNA-binding proteins that increase the local concentration of RNA-binding proteins in alternative exon loci of nucleosomes by binding specific modified histone proteins, leading to alternative splicing. This crosstalk mechanism may play a major role in epigenetic processes such as histone modification and the regulation of alternative splicing.
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Affiliation(s)
- Yong-Eun Kim
- Department of Biochemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Chungoo Park
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Kyoon Eon Kim
- Department of Biochemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Kee K Kim
- Department of Biochemistry, Chungnam National University, Daejeon, 34134, Republic of Korea.
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