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Liao SE, Sudarshan M, Regev O. Deciphering RNA splicing logic with interpretable machine learning. Proc Natl Acad Sci U S A 2023; 120:e2221165120. [PMID: 37796983 PMCID: PMC10576025 DOI: 10.1073/pnas.2221165120] [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: 01/06/2023] [Accepted: 08/29/2023] [Indexed: 10/07/2023] Open
Abstract
Machine learning methods, particularly neural networks trained on large datasets, are transforming how scientists approach scientific discovery and experimental design. However, current state-of-the-art neural networks are limited by their uninterpretability: Despite their excellent accuracy, they cannot describe how they arrived at their predictions. Here, using an "interpretable-by-design" approach, we present a neural network model that provides insights into RNA splicing, a fundamental process in the transfer of genomic information into functional biochemical products. Although we designed our model to emphasize interpretability, its predictive accuracy is on par with state-of-the-art models. To demonstrate the model's interpretability, we introduce a visualization that, for any given exon, allows us to trace and quantify the entire decision process from input sequence to output splicing prediction. Importantly, the model revealed uncharacterized components of the splicing logic, which we experimentally validated. This study highlights how interpretable machine learning can advance scientific discovery.
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Affiliation(s)
- Susan E. Liao
- Department of Computer Science, Courant Institute of Mathematical Sciences, New York University, New York, NY10012
| | - Mukund Sudarshan
- Department of Computer Science, Courant Institute of Mathematical Sciences, New York University, New York, NY10012
| | - Oded Regev
- Department of Computer Science, Courant Institute of Mathematical Sciences, New York University, New York, NY10012
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2
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Li Z, Wei H, Hu D, Li X, Guo Y, Ding X, Guo H, Zhang L. Research Progress on the Structural and Functional Roles of hnRNPs in Muscle Development. Biomolecules 2023; 13:1434. [PMID: 37892116 PMCID: PMC10604023 DOI: 10.3390/biom13101434] [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: 09/04/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023] Open
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a superfamily of RNA-binding proteins consisting of more than 20 members. These proteins play a crucial role in various biological processes by regulating RNA splicing, transcription, and translation through their binding to RNA. In the context of muscle development and regeneration, hnRNPs are involved in a wide range of regulatory mechanisms, including alternative splicing, transcription regulation, miRNA regulation, and mRNA stability regulation. Recent studies have also suggested a potential association between hnRNPs and muscle-related diseases. In this report, we provide an overview of our current understanding of how hnRNPs regulate RNA metabolism and emphasize the significance of the key members of the hnRNP family in muscle development. Furthermore, we explore the relationship between the hnRNP family and muscle-related diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Linlin Zhang
- Key Laboratory of Animal Breeding and Healthy Livestock Farming, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin 300392, China; (Z.L.); (H.W.); (D.H.); (X.L.); (Y.G.); (X.D.); (H.G.)
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3
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Brownmiller T, Caplen NJ. The HNRNPF/H RNA binding proteins and disease. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1788. [PMID: 37042074 PMCID: PMC10523889 DOI: 10.1002/wrna.1788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 04/13/2023]
Abstract
The members of the HNRNPF/H family of heterogeneous nuclear RNA proteins-HNRNPF, HNRNPH1, HNRNPH2, HNRNPH3, and GRSF1, are critical regulators of RNA maturation. Documented functions of these proteins include regulating splicing, particularly alternative splicing, 5' capping and 3' polyadenylation of RNAs, and RNA export. The assignment of these proteins to the HNRNPF/H protein family members relates to differences in the amino acid composition of their RNA recognition motifs, which differ from those of other RNA binding proteins (RBPs). HNRNPF/H proteins typically bind RNA sequences enriched with guanine (G) residues, including sequences that, in the presence of a cation, have the potential to form higher-order G-quadruplex structures. The need to further investigate members of the HNRNPF/H family of RBPs has intensified with the recent descriptions of their involvement in several disease states, including the pediatric tumor Ewing sarcoma and the hematological malignancy mantle cell lymphoma; newly described groups of developmental syndromes; and neuronal-related disorders, including addictive behavior. Here, to foster the study of the HNRNPF/H family of RBPs, we discuss features of the genes encoding these proteins, their structures and functions, and emerging contributions to disease. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Tayvia Brownmiller
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, Maryland, USA
| | - Natasha J Caplen
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, Maryland, USA
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4
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Qureshi QUA, Audas TE, Morin RD, Coyle KM. Emerging roles for heterogeneous ribonuclear proteins in normal and malignant B cells. Biochem Cell Biol 2023; 101:160-171. [PMID: 36745874 DOI: 10.1139/bcb-2022-0332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are among the most abundantly expressed RNA binding proteins in the cell and play major roles in all facets of RNA metabolism. hnRNPs are increasingly appreciated as essential for mammalian B cell development by regulating the carefully ordered expression of specific genes. Due to this tight regulation of the hnRNP-RNA network, it is no surprise that a growing number of genes encoding hnRNPs have been causally associated with the onset or progression of many cancers, including B cell neoplasms. Here we discuss our current understanding of hnRNP-driven regulation in normal, perturbed, and malignant B cells, and the most recent and emerging therapeutic innovations aimed at targeting the hnRNP-RNA network in lymphoma.
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Affiliation(s)
- Qurat Ul Ain Qureshi
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Timothy E Audas
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Ryan D Morin
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Canada's Michael Smith Genome Sciences Centre at BC Cancer, Vancouver, BC, Canada
| | - Krysta M Coyle
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, Canada
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5
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Petersen USS, Doktor TK, Andresen BS. Pseudoexon activation in disease by non-splice site deep intronic sequence variation - wild type pseudoexons constitute high-risk sites in the human genome. Hum Mutat 2021; 43:103-127. [PMID: 34837434 DOI: 10.1002/humu.24306] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 11/02/2021] [Accepted: 11/06/2021] [Indexed: 12/27/2022]
Abstract
Accuracy of pre-messenger RNA (pre-mRNA) splicing is crucial for normal gene expression. Complex regulation supports the spliceosomal distinction between authentic exons and the many seemingly functional splice sites delimiting pseudoexons. Pseudoexons are nonfunctional intronic sequences that can be activated for aberrant inclusion in mRNA, which may cause disease. Pseudoexon activation is very challenging to predict, in particular when activation occurs by sequence variants that alter the splicing regulatory environment without directly affecting splice sites. As pseudoexon inclusion often evades detection due to activation of nonsense-mediated mRNA decay, and because conventional diagnostic procedures miss deep intronic sequence variation, pseudoexon activation is a heavily underreported disease mechanism. Pseudoexon characteristics have mainly been studied based on in silico predicted sequences. Moreover, because recognition of sequence variants that create or strengthen splice sites is possible by comparison with well-established consensus sequences, this type of pseudoexon activation is by far the most frequently reported. Here we review all known human disease-associated pseudoexons that carry functional splice sites and are activated by deep intronic sequence variants located outside splice site sequences. We delineate common characteristics that make this type of wild type pseudoexons distinct high-risk sites in the human genome.
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Affiliation(s)
- Ulrika S S Petersen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Thomas K Doktor
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense M, Denmark
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6
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Biology of the mRNA Splicing Machinery and Its Dysregulation in Cancer Providing Therapeutic Opportunities. Int J Mol Sci 2021; 22:ijms22105110. [PMID: 34065983 PMCID: PMC8150589 DOI: 10.3390/ijms22105110] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022] Open
Abstract
Dysregulation of messenger RNA (mRNA) processing—in particular mRNA splicing—is a hallmark of cancer. Compared to normal cells, cancer cells frequently present aberrant mRNA splicing, which promotes cancer progression and treatment resistance. This hallmark provides opportunities for developing new targeted cancer treatments. Splicing of precursor mRNA into mature mRNA is executed by a dynamic complex of proteins and small RNAs called the spliceosome. Spliceosomes are part of the supraspliceosome, a macromolecular structure where all co-transcriptional mRNA processing activities in the cell nucleus are coordinated. Here we review the biology of the mRNA splicing machinery in the context of other mRNA processing activities in the supraspliceosome and present current knowledge of its dysregulation in lung cancer. In addition, we review investigations to discover therapeutic targets in the spliceosome and give an overview of inhibitors and modulators of the mRNA splicing process identified so far. Together, this provides insight into the value of targeting the spliceosome as a possible new treatment for lung cancer.
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Liao SE, Regev O. Splicing at the phase-separated nuclear speckle interface: a model. Nucleic Acids Res 2021; 49:636-645. [PMID: 33337476 PMCID: PMC7826271 DOI: 10.1093/nar/gkaa1209] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023] Open
Abstract
Phase-separated membraneless bodies play important roles in nucleic acid biology. While current models for the roles of phase separation largely focus on the compartmentalization of constituent proteins, we reason that other properties of phase separation may play functional roles. Specifically, we propose that interfaces of phase-separated membraneless bodies could have functional roles in spatially organizing biochemical reactions. Here we propose such a model for the nuclear speckle, a membraneless body implicated in RNA splicing. In our model, sequence-dependent RNA positioning along the nuclear speckle interface coordinates RNA splicing. Our model asserts that exons are preferentially sequestered into nuclear speckles through binding by SR proteins, while introns are excluded through binding by nucleoplasmic hnRNP proteins. As a result, splice sites at exon-intron boundaries are preferentially positioned at nuclear speckle interfaces. This positioning exposes splice sites to interface-localized spliceosomes, enabling the subsequent splicing reaction. Our model provides a simple mechanism that seamlessly explains much of the complex logic of splicing. This logic includes experimental results such as the antagonistic duality between splicing factors, the position dependence of splicing sequence motifs, and the collective contribution of many motifs to splicing decisions. Similar functional roles for phase-separated interfaces may exist for other membraneless bodies.
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Affiliation(s)
- Susan E Liao
- Computer Science Department, Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
| | - Oded Regev
- Computer Science Department, Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
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8
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Nikolaou KC, Vatandaslar H, Meyer C, Schmid MW, Tuschl T, Stoffel M. The RNA-Binding Protein A1CF Regulates Hepatic Fructose and Glycerol Metabolism via Alternative RNA Splicing. Cell Rep 2020; 29:283-300.e8. [PMID: 31597092 DOI: 10.1016/j.celrep.2019.08.100] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/09/2019] [Accepted: 08/29/2019] [Indexed: 01/11/2023] Open
Abstract
The regulation of hepatic gene expression has been extensively studied at the transcriptional level; however, the control of metabolism through posttranscriptional gene regulation by RNA-binding proteins in physiological and disease states is less understood. Here, we report a major role for the hormone-sensitive RNA-binding protein (RBP) APOBEC1 complementation factor (A1CF) in the generation of hepatocyte-specific and alternatively spliced transcripts. Among these transcripts are isoforms for the dominant and high-affinity fructose-metabolizing ketohexokinase C and glycerol kinase, two key metabolic enzymes that are linked to hepatic gluconeogenesis and found to be markedly reduced upon hepatic ablation of A1cf. Consequently, mice lacking A1CF exhibit improved glucose tolerance and are protected from fructose-induced hyperglycemia, hepatic steatosis, and development of obesity. Our results identify a previously unreported function of A1CF as a regulator of alternative splicing of a subset of genes influencing hepatic glucose production through fructose and glycerol metabolism.
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Affiliation(s)
- Kostas C Nikolaou
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093 Zürich, Switzerland
| | - Hasan Vatandaslar
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093 Zürich, Switzerland
| | - Cindy Meyer
- Laboratory of RNA Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | - Marc W Schmid
- MWSchmid GmbH, Möhrlistrasse 25, 8006 Zurich, Switzerland
| | - Thomas Tuschl
- Laboratory of RNA Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
| | - Markus Stoffel
- Institute of Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093 Zürich, Switzerland; Medical Faculty, University of Zurich, 8091 Zurich, Switzerland.
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Neckles C, Boer RE, Aboreden N, Cross AM, Walker RL, Kim BH, Kim S, Schneekloth JS, Caplen NJ. HNRNPH1-dependent splicing of a fusion oncogene reveals a targetable RNA G-quadruplex interaction. RNA (NEW YORK, N.Y.) 2019; 25:1731-1750. [PMID: 31511320 PMCID: PMC6859848 DOI: 10.1261/rna.072454.119] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/08/2019] [Indexed: 05/05/2023]
Abstract
The primary oncogenic event in ∼85% of Ewing sarcomas is a chromosomal translocation that generates a fusion oncogene encoding an aberrant transcription factor. The exact genomic breakpoints within the translocated genes, EWSR1 and FLI1, vary; however, in EWSR1, breakpoints typically occur within introns 7 or 8. We previously found that in Ewing sarcoma cells harboring EWSR1 intron 8 breakpoints, the RNA-binding protein HNRNPH1 facilitates a splicing event that excludes EWSR1 exon 8 from the EWS-FLI1 pre-mRNA to generate an in-frame mRNA. Here, we show that the processing of distinct EWS-FLI1 pre-mRNAs by HNRNPH1, but not other homologous family members, resembles alternative splicing of transcript variants of EWSR1 We demonstrate that HNRNPH1 recruitment is driven by guanine-rich sequences within EWSR1 exon 8 that have the potential to fold into RNA G-quadruplex structures. Critically, we demonstrate that an RNA mimetic of one of these G-quadruplexes modulates HNRNPH1 binding and induces a decrease in the growth of an EWSR1 exon 8 fusion-positive Ewing sarcoma cell line. Finally, we show that EWSR1 exon 8 fusion-positive cell lines are more sensitive to treatment with the pan-quadruplex binding molecule, pyridostatin (PDS), than EWSR1 exon 8 fusion-negative lines. Also, the treatment of EWSR1 exon 8 fusion-positive cells with PDS decreases EWS-FLI1 transcriptional activity, reversing the transcriptional deregulation driven by EWS-FLI1. Our findings illustrate that modulation of the alternative splicing of EWS-FLI1 pre-mRNA is a novel strategy for future therapeutics against the EWSR1 exon 8 containing fusion oncogenes present in a third of Ewing sarcoma.
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Affiliation(s)
- Carla Neckles
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Robert E Boer
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, USA
| | - Nicholas Aboreden
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Allison M Cross
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Robert L Walker
- Molecular Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - Bong-Hyun Kim
- CCR Collaborative Bioinformatics Resource, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland 21702, USA
| | - Suntae Kim
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
| | - John S Schneekloth
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, USA
| | - Natasha J Caplen
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
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Katneni UK, Liss A, Holcomb D, Katagiri NH, Hunt R, Bar H, Ismail A, Komar AA, Kimchi‐Sarfaty C. Splicing dysregulation contributes to the pathogenicity of several F9 exonic point variants. Mol Genet Genomic Med 2019; 7:e840. [PMID: 31257730 PMCID: PMC6687662 DOI: 10.1002/mgg3.840] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 06/10/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Pre-mRNA splicing is a complex process requiring the identification of donor site, acceptor site, and branch point site with an adjacent polypyrimidine tract sequence. Splicing is regulated by splicing regulatory elements (SREs) with both enhancer and suppressor functions. Variants located in exonic regions can impact splicing through dysregulation of native splice sites, SREs, and cryptic splice site activation. While splicing dysregulation is considered primary disease-inducing mechanism of synonymous variants, its contribution toward disease phenotype of non-synonymous variants is underappreciated. METHODS In this study, we analyzed 415 disease-causing and 120 neutral F9 exonic point variants including both synonymous and non-synonymous for their effect on splicing using a series of in silico splice site prediction tools, SRE prediction tools, and in vitro minigene assays. RESULTS The use of splice site and SRE prediction tools in tandem provided better prediction but were not always in agreement with the minigene assays. The net effect of splicing dysregulation caused by variants was context dependent. Minigene assays revealed that perturbed splicing can be found. CONCLUSION Synonymous variants primarily cause disease phenotype via splicing dysregulation while additional mechanisms such as translation rate also play an important role. Splicing dysregulation is likely to contribute to the disease phenotype of several non-synonymous variants.
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Affiliation(s)
- Upendra K. Katneni
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & ResearchUS FDASilver SpringMaryland
| | - Aaron Liss
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & ResearchUS FDASilver SpringMaryland
| | - David Holcomb
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & ResearchUS FDASilver SpringMaryland
| | - Nobuko H. Katagiri
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & ResearchUS FDASilver SpringMaryland
| | - Ryan Hunt
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & ResearchUS FDASilver SpringMaryland
| | - Haim Bar
- Department of StatisticsUniversity of ConnecticutStorrsConnecticut
| | - Amra Ismail
- Department of Biological, Geological and Environmental Sciences, Center for Gene Regulation in Health and DiseaseCleveland State UniversityClevelandOhio
| | - Anton A. Komar
- Department of Biological, Geological and Environmental Sciences, Center for Gene Regulation in Health and DiseaseCleveland State UniversityClevelandOhio
| | - Chava Kimchi‐Sarfaty
- Hemostasis Branch, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation & ResearchUS FDASilver SpringMaryland
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11
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Wang K, Wu D, Zhang H, Das A, Basu M, Malin J, Cao K, Hannenhalli S. Comprehensive map of age-associated splicing changes across human tissues and their contributions to age-associated diseases. Sci Rep 2018; 8:10929. [PMID: 30026530 PMCID: PMC6053367 DOI: 10.1038/s41598-018-29086-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/23/2018] [Indexed: 12/31/2022] Open
Abstract
Alternative splicing contributes to phenotypic diversity at multiple biological scales, and its dysregulation is implicated in both ageing and age-associated diseases in human. Cross-tissue variability in splicing further complicates its links to age-associated phenotypes and elucidating these links requires a comprehensive map of age-associated splicing changes across multiple tissues. Here, we generate such a map by analyzing ~8500 RNA-seq samples across 48 tissues in 544 individuals. Employing a stringent model controlling for multiple confounders, we identify 49,869 tissue-specific age-associated splicing events of 7 distinct types. We find that genome-wide splicing profile is a better predictor of biological age than the gene and transcript expression profiles, and furthermore, age-associated splicing provides additional independent contribution to age-associated complex diseases. We show that the age-associated splicing changes may be explained, in part, by concomitant age-associated changes of the upstream splicing factors. Finally, we show that our splicing-based model of age can successfully predict the relative ages of cells in 8 of the 10 paired longitudinal data as well as in 2 sets of cell passage data. Our study presents the first systematic investigation of age-associated splicing changes across tissues, and further strengthening the links between age-associated splicing and age-associated diseases.
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Affiliation(s)
- Kun Wang
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20742, USA
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Di Wu
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Haoyue Zhang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Avinash Das
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20742, USA
| | - Mahashweta Basu
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20742, USA
| | - Justin Malin
- Computational Biology Branch, National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kan Cao
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
| | - Sridhar Hannenhalli
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20742, USA.
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
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12
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Suess B, Kemmerer K, Weigand JE. Splicing and Alternative Splicing Impact on Gene Design. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Beatrix Suess
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Katrin Kemmerer
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
| | - Julia E. Weigand
- Department of Biology; Technische Universität Darmstadt; Schnittspahnstraße 10 64287 Darmstadt Germany
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13
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Bose D, D V, Shetty M, J K, Kutty AVM. Identification of intronic-splice site mutations in GATA4 gene in Indian patients with congenital heart disease. Mutat Res 2017; 803-805:26-34. [PMID: 28843068 DOI: 10.1016/j.mrfmmm.2017.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/01/2017] [Accepted: 08/08/2017] [Indexed: 12/19/2022]
Abstract
Congenital Heart Disease (CHD) is the most common birth defect among congenital anomalies that arise before birth. GATA4 transcription factor plays an important role in foetal heart development. Mutational analysis of GATA4 gene in CHD patients revealed five known heterozygous mutations (p.T355S, p.S377G, p.V380M, p.P394T and p.D425N) identified in exons 5 and 6 regions and fifteen intronic variants in the non-coding regions (g.76885T>C/Y,g.76937G>S, g.78343G>R, g.83073T>Y, g.83271C>A/M, g.83318G>K, g.83415G>R, g.83502A>C/M, g.84991G>R, g.85294C>Y, g.85342C>T/Y, g.86268A>R, g.87409G>A/R, g.87725T>Y, g.87813A>T/W). In silico analysis of these intronic variants identified two potential branch point mutations (g.83271C>A/M, g.86268A>R) and predicted effects of these on intronic splice sites as enhancer and silencer motifs. This study attempts to correlate the pattern of intronic variants of GATA4 gene which might provide new insights to unravel the possible molecular etiology of CHD.
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Affiliation(s)
- Divya Bose
- Division of Genomics, Department of Cell Biology and Molecular Genetics, Sri Devaraj Urs Academy of Higher Education and Research, Tamaka, Kolar, Karnataka, India
| | - Vaigundan D
- Division of Genomics, Department of Cell Biology and Molecular Genetics, Sri Devaraj Urs Academy of Higher Education and Research, Tamaka, Kolar, Karnataka, India
| | - Mitesh Shetty
- Division of Genomics, Department of Cell Biology and Molecular Genetics, Sri Devaraj Urs Academy of Higher Education and Research, Tamaka, Kolar, Karnataka, India
| | - Krishnappa J
- Department of Pediatrics, Sri Devaraj Urs Medical College, R. L. Jalappa Hospital and Research Centre, Tamaka, Kolar, Karnataka, India
| | - A V M Kutty
- Division of Genomics, Department of Cell Biology and Molecular Genetics, Sri Devaraj Urs Academy of Higher Education and Research, Tamaka, Kolar, Karnataka, India.
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14
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Zhu C, Chen Z, Guo W. Pre-mRNA mis-splicing of sarcomeric genes in heart failure. Biochim Biophys Acta Mol Basis Dis 2016; 1863:2056-2063. [PMID: 27825848 DOI: 10.1016/j.bbadis.2016.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 10/11/2016] [Accepted: 11/01/2016] [Indexed: 12/01/2022]
Abstract
Pre-mRNA splicing is an important biological process that allows production of multiple proteins from a single gene in the genome, and mainly contributes to protein diversity in eukaryotic organisms. Alternative splicing is commonly governed by RNA binding proteins to meet the ever-changing demands of the cell. However, the mis-splicing may lead to human diseases. In the heart of human, mis-regulation of alternative splicing has been associated with heart failure. In this short review, we focus on alternative splicing of sarcomeric genes and review mis-splicing related heart failure with relatively well studied Sarcomeric genes and splicing mechanisms with identified regulatory factors. The perspective of alternative splicing based therapeutic strategies in heart failure has also been discussed.
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Affiliation(s)
- Chaoqun Zhu
- Animal Science, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA
| | - Zhilong Chen
- Animal Science, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA; College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Wei Guo
- Animal Science, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA
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Serine/Arginine-Rich Splicing Factor 3 and Heterogeneous Nuclear Ribonucleoprotein A1 Regulate Alternative RNA Splicing and Gene Expression of Human Papillomavirus 18 through Two Functionally Distinguishable cis Elements. J Virol 2016; 90:9138-52. [PMID: 27489271 DOI: 10.1128/jvi.00965-16] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/25/2016] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED Human papillomavirus 18 (HPV18) is the second most common oncogenic HPV type associated with cervical, anogenital, and oropharyngeal cancers. Like other oncogenic HPVs, HPV18 encodes two major (one early and one late) polycistronic pre-mRNAs that are regulated by alternative RNA splicing to produce a repertoire of viral transcripts for the expression of individual viral genes. However, RNA cis-regulatory elements and trans-acting factors contributing to HPV18 alternative RNA splicing remain unknown. In this study, an exonic splicing enhancer (ESE) in the nucleotide (nt) 3520 to 3550 region in the HPV18 genome was identified and characterized for promotion of HPV18 929^3434 splicing and E1^E4 production through interaction with SRSF3, a host oncogenic splicing factor differentially expressed in epithelial cells and keratinocytes. Introduction of point mutations in the SRSF3-binding site or knockdown of SRSF3 expression in cells reduces 929^3434 splicing and E1^E4 production but activates other, minor 929^3465 and 929^3506 splicing. Knockdown of SRSF3 expression also enhances the expression of E2 and L1 mRNAs. An exonic splicing silencer (ESS) in the HPV18 nt 612 to 639 region was identified as being inhibitory to the 233^416 splicing of HPV18 E6E7 pre-mRNAs via binding to hnRNP A1, a well-characterized, abundantly and ubiquitously expressed RNA-binding protein. Introduction of point mutations into the hnRNP A1-binding site or knockdown of hnRNP A1 expression promoted 233^416 splicing and reduced E6 expression. These data provide the first evidence that the alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host trans-acting splicing factors. IMPORTANCE Expression of HPV18 genes is regulated by alternative RNA splicing of viral polycistronic pre-mRNAs to produce a repertoire of viral early and late transcripts. RNA cis elements and trans-acting factors contributing to HPV18 alternative RNA splicing have been discovered in this study for the first time. The identified ESS at the E7 open reading frame (ORF) prevents HPV18 233^416 splicing in the E6 ORF through interaction with a host splicing factor, hnRNP A1, and regulates E6 and E7 expression of the early E6E7 polycistronic pre-mRNA. The identified ESE at the E1^E4 ORF promotes HPV18 929^3434 splicing of both viral early and late pre-mRNAs and E1^E4 production through interaction with SRSF3. This study provides important observations on how alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host splicing factors and offers potential therapeutic targets to overcome HPV-related cancer.
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16
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Yang Y, Jia D, Kim H, Abd Elmageed ZY, Datta A, Davis R, Srivastav S, Moroz K, Crawford BE, Moparty K, Thomas R, Hudson RS, Ambs S, Abdel-Mageed AB. Dysregulation of miR-212 Promotes Castration Resistance through hnRNPH1-Mediated Regulation of AR and AR-V7: Implications for Racial Disparity of Prostate Cancer. Clin Cancer Res 2015; 22:1744-56. [PMID: 26553749 DOI: 10.1158/1078-0432.ccr-15-1606] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/11/2015] [Indexed: 12/31/2022]
Abstract
PURPOSE The causes of disproportionate incidence and mortality of prostate cancer among African Americans (AA) remain elusive. The purpose of this study was to investigate the mechanistic role and assess clinical utility of the splicing factor heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1) in prostate cancer progression among AA men. EXPERIMENTAL DESIGN We employed an unbiased functional genomics approach coupled with suppressive subtractive hybridization (SSH) and custom cDNA microarrays to identify differentially expressed genes in microdissected tumors procured from age- and tumor grade-matched AA and Caucasian American (CA) men. Validation analysis was performed in independent cohorts and tissue microarrays. The underlying mechanisms of hnRNPH1 regulation and its impact on androgen receptor (AR) expression and tumor progression were explored. RESULTS Aberrant coexpression of AR and hnRNPH1 and downregulation of miR-212 were detected in prostate tumors and correlate with disease progression in AA men compared with CA men. Ectopic expression of miR-212 mimics downregulated hnRNPH1 transcripts, which in turn reduced expression of AR and its splice variant AR-V7 (or AR3) in prostate cancer cells. hnRNPH1 physically interacts with AR and steroid receptor coactivator-3 (SRC-3) and primes activation of androgen-regulated genes in a ligand-dependent and independent manner. siRNA silencing of hnRNPH1 sensitized prostate cancer cells to bicalutamide and inhibited prostate tumorigenesis in vivo CONCLUSIONS Our findings define novel roles for hnRNPH1 as a putative oncogene, splicing factor, and an auxiliary AR coregulator. Targeted disruption of the hnRNPH1-AR axis may have therapeutic implications to improve clinical outcomes in patients with advanced prostate cancer, especially among AA men.
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Affiliation(s)
- Yijun Yang
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Dingwu Jia
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Hogyoung Kim
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana
| | | | - Amrita Datta
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Rodney Davis
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Sudesh Srivastav
- Department of Biostatistics, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Krzysztof Moroz
- Department of Pathology, Tulane University School of Medicine, New Orleans, Louisiana. Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Byron E Crawford
- Department of Pathology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Krishnarao Moparty
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana. Division of Urology, Southeast Louisiana Veterans Health Care System, New Orleans, Louisiana
| | - Raju Thomas
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana. Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana
| | - Robert S Hudson
- Laboratory of Human Carcinogenesis, National Cancer Institute, NIH, Bethesda, Maryland
| | - Stefan Ambs
- Laboratory of Human Carcinogenesis, National Cancer Institute, NIH, Bethesda, Maryland
| | - Asim B Abdel-Mageed
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana. Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana. Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana.
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17
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Evolutionary emergence of a novel splice variant with an opposite effect on the cell cycle. Mol Cell Biol 2015; 35:2203-14. [PMID: 25870105 DOI: 10.1128/mcb.00190-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/06/2015] [Indexed: 11/20/2022] Open
Abstract
Alternative splicing contributes greatly to the diversification of mammalian proteomes, but the molecular basis for the evolutionary emergence of splice variants remains poorly understood. We have recently found a novel class of splicing regulatory elements between the polypyrimidine tract (Py) and 3' AG (REPA) at intron ends in many human genes, including the multifunctional PRMT5 (for protein arginine methyltransferase 5) gene. The PRMT5 element is comprised of two G tracts that arise in most mammals and accompany significant exon skipping in human transcripts. The G tracts inhibit splicing by recruiting heterogeneous nuclear ribonucleoprotein (hnRNP) H and F (H/F) to reduce U2AF65 binding to the Py, causing exon skipping. The resulting novel shorter variant PRMT5S exhibits a histone H4R3 methylation effect similar to that seen with the original longer PRMT5L isoform but exhibits a distinct localization and preferential control of critical genes for cell cycle arrest at interphase in comparison to PRMT5L. This report thus provides a molecular mechanism for the evolutionary emergence of a novel splice variant with an opposite function in a fundamental cell process. The presence of REPA elements in a large group of genes implies their wider impact on different cellular processes for increased protein diversity in humans.
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18
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Niklas KJ, Bondos SE, Dunker AK, Newman SA. Rethinking gene regulatory networks in light of alternative splicing, intrinsically disordered protein domains, and post-translational modifications. Front Cell Dev Biol 2015; 3:8. [PMID: 25767796 PMCID: PMC4341551 DOI: 10.3389/fcell.2015.00008] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/26/2015] [Indexed: 11/16/2022] Open
Abstract
Models for genetic regulation and cell fate specification characteristically assume that gene regulatory networks (GRNs) are essentially deterministic and exhibit multiple stable states specifying alternative, but pre-figured cell fates. Mounting evidence shows, however, that most eukaryotic precursor RNAs undergo alternative splicing (AS) and that the majority of transcription factors contain intrinsically disordered protein (IDP) domains whose functionalities are context dependent as well as subject to post-translational modification (PTM). Consequently, many transcription factors do not have fixed cis-acting regulatory targets, and developmental determination by GRNs alone is untenable. Modeling these phenomena requires a multi-scale approach to explain how GRNs operationally interact with the intra- and intercellular environments. Evidence shows that AS, IDP, and PTM complicate gene expression and act synergistically to facilitate and promote time- and cell-specific protein modifications involved in cell signaling and cell fate specification and thereby disrupt a strict deterministic GRN-phenotype mapping. The combined effects of AS, IDP, and PTM give proteomes physiological plasticity, adaptive responsiveness, and developmental versatility without inefficiently expanding genome size. They also help us understand how protein functionalities can undergo major evolutionary changes by buffering mutational consequences.
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Affiliation(s)
- Karl J Niklas
- Plant Biology Section, School of Integrative Plant Science, Cornell University Ithaca, NY, USA
| | - Sarah E Bondos
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College Station, TX, USA
| | - A Keith Dunker
- Center for Computational Biology and Bioinformatics, School of Medicine, Indiana University Indianapolis, IN, USA
| | - Stuart A Newman
- Department of Cell Biology and Anatomy, New York Medical College Valhalla, NY, USA
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19
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A heroin addiction severity-associated intronic single nucleotide polymorphism modulates alternative pre-mRNA splicing of the μ opioid receptor gene OPRM1 via hnRNPH interactions. J Neurosci 2014; 34:11048-66. [PMID: 25122903 DOI: 10.1523/jneurosci.3986-13.2014] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Single nucleotide polymorphisms (SNPs) in the OPRM1 gene have been associated with vulnerability to opioid dependence. The current study identifies an association of an intronic SNP (rs9479757) with the severity of heroin addiction among Han-Chinese male heroin addicts. Individual SNP analysis and haplotype-based analysis with additional SNPs in the OPRM1 locus showed that mild heroin addiction was associated with the AG genotype, whereas severe heroin addiction was associated with the GG genotype. In vitro studies such as electrophoretic mobility shift assay, minigene, siRNA, and antisense morpholino oligonucleotide studies have identified heterogeneous nuclear ribonucleoprotein H (hnRNPH) as the major binding partner for the G-containing SNP site. The G-to-A transition weakens hnRNPH binding and facilitates exon 2 skipping, leading to altered expressions of OPRM1 splice-variant mRNAs and hMOR-1 proteins. Similar changes in splicing and hMOR-1 proteins were observed in human postmortem prefrontal cortex with the AG genotype of this SNP when compared with the GG genotype. Interestingly, the altered splicing led to an increase in hMOR-1 protein levels despite decreased hMOR-1 mRNA levels, which is likely contributed by a concurrent increase in single transmembrane domain variants that have a chaperone-like function on MOR-1 protein stability. Our studies delineate the role of this SNP as a modifier of OPRM1 alternative splicing via hnRNPH interactions, and suggest a functional link between an SNP-containing splicing modifier and the severity of heroin addiction.
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20
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Abstract
Sequence-specific RNA-binding proteins (RBPs) bind to pre-mRNA to control alternative splicing, but it is not yet possible to read the 'splicing code' that dictates splicing regulation on the basis of genome sequence. Each alternative splicing event is controlled by multiple RBPs, the combined action of which creates a distribution of alternatively spliced products in a given cell type. As each cell type expresses a distinct array of RBPs, the interpretation of regulatory information on a given RNA target is exceedingly dependent on the cell type. RBPs also control each other's functions at many levels, including by mutual modulation of their binding activities on specific regulatory RNA elements. In this Review, we describe some of the emerging rules that govern the highly context-dependent and combinatorial nature of alternative splicing regulation.
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Affiliation(s)
- Xiang-Dong Fu
- Department of Cellular and Molecular Medicine and Institute for Genomic, Medicine, University of California San Diego, La Jolla, California 92093–0651, USA
| | - Manuel Ares
- Center for Molecular Biology of RNA, and Department of Molecular, Cell, and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
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21
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A targeted oligonucleotide enhancer of SMN2 exon 7 splicing forms competing quadruplex and protein complexes in functional conditions. Cell Rep 2014; 9:193-205. [PMID: 25263560 PMCID: PMC4536295 DOI: 10.1016/j.celrep.2014.08.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/17/2014] [Accepted: 08/21/2014] [Indexed: 01/20/2023] Open
Abstract
The use of oligonucleotides to activate the splicing of selected exons is limited by a poor understanding of the mechanisms affected. A targeted bifunctional oligonucleotide enhancer of splicing (TOES) anneals to SMN2 exon 7 and carries an exonic splicing enhancer (ESE) sequence. We show that it stimulates splicing specifically of intron 6 in the presence of repressing sequences in intron 7. Complementarity to the 5' end of exon 7 increases U2AF65 binding, but the ESE sequence is required for efficient recruitment of U2 snRNP. The ESE forms at least three coexisting discrete states: a quadruplex, a complex containing only hnRNP F/H, and a complex enriched in the activator SRSF1. Neither hnRNP H nor quadruplex formation contributes to ESE activity. The results suggest that splicing limited by weak signals can be rescued by rapid exchange of TOES oligonucleotides in various complexes and raise the possibility that SR proteins associate transiently with ESEs.
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22
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Dardenne E, Polay Espinoza M, Fattet L, Germann S, Lambert MP, Neil H, Zonta E, Mortada H, Gratadou L, Deygas M, Chakrama FZ, Samaan S, Desmet FO, Tranchevent LC, Dutertre M, Rimokh R, Bourgeois CF, Auboeuf D. RNA helicases DDX5 and DDX17 dynamically orchestrate transcription, miRNA, and splicing programs in cell differentiation. Cell Rep 2014; 7:1900-13. [PMID: 24910439 DOI: 10.1016/j.celrep.2014.05.010] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 04/08/2014] [Accepted: 05/05/2014] [Indexed: 02/07/2023] Open
Abstract
The RNA helicases DDX5 and DDX17 are members of a large family of highly conserved proteins that are involved in gene-expression regulation; however, their in vivo targets and activities in biological processes such as cell differentiation, which requires reprogramming of gene-expression programs at multiple levels, are not well characterized. Here, we uncovered a mechanism by which DDX5 and DDX17 cooperate with heterogeneous nuclear ribonucleoprotein (hnRNP) H/F splicing factors to define epithelial- and myoblast-specific splicing subprograms. We then observed that downregulation of DDX5 and DDX17 protein expression during myogenesis and epithelial-to-mesenchymal transdifferentiation contributes to the switching of splicing programs during these processes. Remarkably, this downregulation is mediated by the production of miRNAs induced upon differentiation in a DDX5/DDX17-dependent manner. Since DDX5 and DDX17 also function as coregulators of master transcriptional regulators of differentiation, we propose to name these proteins "master orchestrators" of differentiation that dynamically orchestrate several layers of gene expression.
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Affiliation(s)
- Etienne Dardenne
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Micaela Polay Espinoza
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Laurent Fattet
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Sophie Germann
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Marie-Pierre Lambert
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Helen Neil
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Eleonora Zonta
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Hussein Mortada
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Lise Gratadou
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Mathieu Deygas
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Fatima Zahra Chakrama
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Samaan Samaan
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - François-Olivier Desmet
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Léon-Charles Tranchevent
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Martin Dutertre
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Ruth Rimokh
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France
| | - Cyril F Bourgeois
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France.
| | - Didier Auboeuf
- INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France; Université Claude Bernard Lyon 1, 69008 Lyon, France; Centre Léon Bérard, 69008 Lyon, France.
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23
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Ma D, Cui L, Gao J, Yan W, Liu Y, Xu S, Wu B. Proteomic analysis of mesenchymal stem cells from normal and deep carious dental pulp. PLoS One 2014; 9:e97026. [PMID: 24809979 PMCID: PMC4014579 DOI: 10.1371/journal.pone.0097026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 04/14/2014] [Indexed: 12/19/2022] Open
Abstract
Dental pulp stem cells (DPSCs), precursor cells of odontoblasts, are ideal seed cells for tooth tissue engineering and regeneration. Our previous study has demonstrated that stem cells exist in dental pulp with deep caries and are called carious dental pulp stem cells (CDPSCs). The results indicated that CDPSCs had a higher proliferative and stronger osteogenic differentiation potential than DPSCs. However, the molecular mechanisms responsible for the biological differences between DPSCs and CDPSCs are poorly understood. The aim of this study was to define the molecular features of DPSCs and CDPSCs by comparing the proteomic profiles using two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) in combination with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Our results revealed that there were 18 protein spots differentially expressed between DPSCs and CDPSCs in a narrow pH range of 4 to 7. These differently expressed proteins are mostly involved in the regulation of cell proliferation, differentiation, cell cytoskeleton and motility. In addition, our results suggested that CDPSCs had a higher expression of antioxidative proteins that might protect CDPSCs from oxidative stress. This study explores some potential proteins responsible for the biological differences between DPSCs and CDPSCs and expands our understanding on the molecular mechanisms of mineralization of DPSCs in the formation of the dentin-pulp complex.
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Affiliation(s)
- Dandan Ma
- Department of Stomatology, Nanfang Hospital, Guangzhou, P.R. China
- College of Stomatology, Southern Medical University, Guangzhou, P.R. China
| | - Li Cui
- Department of Stomatology, Nanfang Hospital, Guangzhou, P.R. China
- College of Stomatology, Southern Medical University, Guangzhou, P.R. China
| | - Jie Gao
- Department of Stomatology, Nanfang Hospital, Guangzhou, P.R. China
- College of Stomatology, Southern Medical University, Guangzhou, P.R. China
| | - Wenjuan Yan
- Department of Stomatology, Nanfang Hospital, Guangzhou, P.R. China
- College of Stomatology, Southern Medical University, Guangzhou, P.R. China
| | - Ying Liu
- Department of Stomatology, Nanfang Hospital, Guangzhou, P.R. China
- College of Stomatology, Southern Medical University, Guangzhou, P.R. China
| | - Shuaimei Xu
- Department of Stomatology, Nanfang Hospital, Guangzhou, P.R. China
- College of Stomatology, Southern Medical University, Guangzhou, P.R. China
| | - Buling Wu
- Department of Stomatology, Nanfang Hospital, Guangzhou, P.R. China
- College of Stomatology, Southern Medical University, Guangzhou, P.R. China
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24
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Juan WC, Roca X, Ong ST. Identification of cis-acting elements and splicing factors involved in the regulation of BIM Pre-mRNA splicing. PLoS One 2014; 9:e95210. [PMID: 24743263 PMCID: PMC3990581 DOI: 10.1371/journal.pone.0095210] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 03/25/2014] [Indexed: 11/25/2022] Open
Abstract
Aberrant changes in the expression of the pro-apoptotic protein, BCL-2-like 11 (BIM), can result in either impaired or excessive apoptosis, which can contribute to tumorigenesis and degenerative disorders, respectively. Altering BIM pre-mRNA splicing is an attractive approach to modulate apoptosis because BIM activity is partly determined by the alternative splicing of exons 3 or 4, whereby exon 3-containing transcripts are not apoptotic. Here we identified several cis-acting elements and splicing factors involved in BIM alternative splicing, as a step to better understand the regulation of BIM expression. We analyzed a recently discovered 2,903-bp deletion polymorphism within BIM intron 2 that biased splicing towards exon 3, and which also impaired BIM-dependent apoptosis. We found that this region harbors multiple redundant cis-acting elements that repress exon 3 inclusion. Furthermore, we have isolated a 23-nt intronic splicing silencer at the 3′ end of the deletion that is important for excluding exon 3. We also show that PTBP1 and hnRNP C repress exon 3 inclusion, and that downregulation of PTBP1 inhibited BIM-mediated apoptosis. Collectively, these findings start building our understanding of the cis-acting elements and splicing factors that regulate BIM alternative splicing, and also suggest potential approaches to alter BIM splicing for therapeutic purposes.
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Affiliation(s)
- Wen Chun Juan
- Cancer and Stem Cell Biology Signature Research Programme, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Xavier Roca
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- * E-mail: (XR); (STO)
| | - S. Tiong Ong
- Cancer and Stem Cell Biology Signature Research Programme, Duke-NUS Graduate Medical School, Singapore, Singapore
- Department of Haematology, Singapore General Hospital, Singapore, Singapore
- Department of Medical Oncology, National Cancer Centre, Singapore, Singapore
- Division of Medical Oncology, Department of Medicine, Duke University Medical Center, Chapel Hill, North Carolina, United States of America
- * E-mail: (XR); (STO)
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25
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Abstract
One of the most amazing findings in molecular biology was the discovery that eukaryotic genes are discontinuous, with coding DNA being interrupted by stretches of non-coding sequence. The subsequent realization that the intervening regions are removed from pre-mRNA transcripts via the activity of a common set of small nuclear RNAs (snRNAs), which assemble together with associated proteins into a complex known as the spliceosome, was equally surprising. How do cells coordinate the assembly of this molecular machine? And how does the spliceosome accurately recognize exons and introns to carry out the splicing reaction? Insights into these questions have been gained by studying the life cycle of spliceosomal snRNAs from their transcription, nuclear export and re-import to their dynamic assembly into the spliceosome. This assembly process can also affect the regulation of alternative splicing and has implications for human disease.
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Affiliation(s)
- A Gregory Matera
- Department of Biology, Department of Genetics and Integrative Program for Biological and Genome Sciences, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Zefeng Wang
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Wu HP, Hsu SY, Wu WA, Hu JW, Ouyang P. Transgenic mice expressing mutant Pinin exhibit muscular dystrophy, nebulin deficiency and elevated expression of slow-type muscle fiber genes. Biochem Biophys Res Commun 2014; 443:313-20. [DOI: 10.1016/j.bbrc.2013.11.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 11/25/2013] [Indexed: 01/19/2023]
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Olsen RKJ, Brøner S, Sabaratnam R, Doktor TK, Andersen HS, Bruun GH, Gahrn B, Stenbroen V, Olpin SE, Dobbie A, Gregersen N, Andresen BS. TheETFDHc.158A>G Variation Disrupts the Balanced Interplay of ESE- and ESS-Binding Proteins thereby Causing Missplicing and Multiple Acyl-CoA Dehydrogenation Deficiency. Hum Mutat 2013; 35:86-95. [DOI: 10.1002/humu.22455] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 09/25/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Rikke K. J. Olsen
- Research Unit for Molecular Medicine; Aarhus University Hospital and Department of Clinical Medicine, Aarhus University; Aarhus Denmark
| | - Sabrina Brøner
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - Rugivan Sabaratnam
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - Thomas K. Doktor
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - Henriette S. Andersen
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - Gitte H. Bruun
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - Birthe Gahrn
- Research Unit for Molecular Medicine; Aarhus University Hospital and Department of Clinical Medicine, Aarhus University; Aarhus Denmark
| | - Vibeke Stenbroen
- Research Unit for Molecular Medicine; Aarhus University Hospital and Department of Clinical Medicine, Aarhus University; Aarhus Denmark
| | - Simon E. Olpin
- Department of Clinical Chemistry; The Children's Hospital; Sheffield United Kingdom
| | - Angus Dobbie
- Department of Clinical Genetics; St James's University Hospital; Leeds United Kingdom
| | - Niels Gregersen
- Research Unit for Molecular Medicine; Aarhus University Hospital and Department of Clinical Medicine, Aarhus University; Aarhus Denmark
| | - Brage S. Andresen
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
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Smith LD, Lucas CM, Eperon IC. Intron retention in the alternatively spliced region of RON results from weak 3' splice site recognition. PLoS One 2013; 8:e77208. [PMID: 24155930 PMCID: PMC3796505 DOI: 10.1371/journal.pone.0077208] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 09/06/2013] [Indexed: 11/19/2022] Open
Abstract
The RON gene encodes a tyrosine kinase receptor for macrophage-stimulating protein. A constitutively active isoform that arises by skipping of exon 11 is expressed in carcinomas and contributes to an invasive phenotype. However, a high proportion of the mRNA expressed from the endogenous gene, or from transfected minigenes, appears to retain introns 10 and 11. It is not known whether this represents specific repression or the presence of weak splicing signals. We have used chimeric pre-mRNAs spliced in vitro to investigate the reason for intron retention. A systematic test showed that, surprisingly, the exon sequences known to modulate exon 11 skipping were not limiting, but the 3’ splice site regions adjacent to exons 11 and 12 were too weak to support splicing when inserted into a globin intron. UV-crosslinking experiments showed binding of hnRNP F/H just 5’ of these regions, but the hnRNP F/H target sequences did not mediate inhibition. Instead, the failure of splicing is linked to weak binding of U2AF65, and spliceosome assembly stalls prior to formation of any of the ATP-dependent complexes. We discuss mechanisms by which U2AF65 binding is facilitated in vivo.
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Affiliation(s)
- Lindsay D. Smith
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Christian M. Lucas
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Ian C. Eperon
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
- * E-mail:
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Juárez-Méndez S, Zentella-Dehesa A, Villegas-Ruíz V, Pérez-González OA, Salcedo M, López-Romero R, Román-Basaure E, Lazos-Ochoa M, Montes de Oca-Fuentes VE, Vázquez-Ortiz G, Moreno J. Splice variants of zinc finger protein 695 mRNA associated to ovarian cancer. J Ovarian Res 2013; 6:61. [PMID: 24007497 PMCID: PMC3847372 DOI: 10.1186/1757-2215-6-61] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/24/2013] [Indexed: 12/22/2022] Open
Abstract
Background Studies of alternative mRNA splicing (AS) in health and disease have yet to yield the complete picture of protein diversity and its role in physiology and pathology. Some forms of cancer appear to be associated to certain alternative mRNA splice variants, but their role in the cancer development and outcome is unclear. Methods We examined AS profiles by means of whole genome exon expression microarrays (Affymetrix GeneChip 1.0) in ovarian tumors and ovarian cancer-derived cell lines, compared to healthy ovarian tissue. Alternatively spliced genes expressed predominantly in ovarian tumors and cell lines were confirmed by RT-PCR. Results Among several significantly overexpressed AS genes in malignant ovarian tumors and ovarian cancer cell lines, the most significant one was that of the zinc finger protein ZNF695, with two previously unknown mRNA splice variants identified in ovarian tumors and cell lines. The identity of ZNF695 AS variants was confirmed by cloning and sequencing of the amplicons obtained from ovarian cancer tissue and cell lines. Conclusions Alternative ZNF695 mRNA splicing could be a marker of ovarian cancer with possible implications on its pathogenesis.
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Cléry A, Sinha R, Anczuków O, Corrionero A, Moursy A, Daubner GM, Valcárcel J, Krainer AR, Allain FHT. Isolated pseudo-RNA-recognition motifs of SR proteins can regulate splicing using a noncanonical mode of RNA recognition. Proc Natl Acad Sci U S A 2013; 110:E2802-11. [PMID: 23836656 PMCID: PMC3725064 DOI: 10.1073/pnas.1303445110] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Serine/arginine (SR) proteins, one of the major families of alternative-splicing regulators in Eukarya, have two types of RNA-recognition motifs (RRMs): a canonical RRM and a pseudo-RRM. Although pseudo-RRMs are crucial for activity of SR proteins, their mode of action was unknown. By solving the structure of the human SRSF1 pseudo-RRM bound to RNA, we discovered a very unusual and sequence-specific RNA-binding mode that is centered on one α-helix and does not involve the β-sheet surface, which typically mediates RNA binding by RRMs. Remarkably, this mode of binding is conserved in all pseudo-RRMs tested. Furthermore, the isolated pseudo-RRM is sufficient to regulate splicing of about half of the SRSF1 target genes tested, and the bound α-helix is a pivotal element for this function. Our results strongly suggest that SR proteins with a pseudo-RRM frequently regulate splicing by competing with, rather than recruiting, spliceosome components, using solely this unusual RRM.
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Affiliation(s)
- Antoine Cléry
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Rahul Sinha
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Olga Anczuków
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Anna Corrionero
- Institució Catalana de Recerca i Estudis Avançats, Universitat Pompeu Fabra 08003 Barcelona, Spain; and
- Centre de Regulació Genòmica, 08003 Barcelona, Spain
| | - Ahmed Moursy
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Gerrit M. Daubner
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Juan Valcárcel
- Institució Catalana de Recerca i Estudis Avançats, Universitat Pompeu Fabra 08003 Barcelona, Spain; and
- Centre de Regulació Genòmica, 08003 Barcelona, Spain
| | | | - Frédéric H.-T. Allain
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
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Gupta SK, Kosti I, Plaut G, Pivko A, Tkacz ID, Cohen-Chalamish S, Biswas DK, Wachtel C, Waldman Ben-Asher H, Carmi S, Glaser F, Mandel-Gutfreund Y, Michaeli S. The hnRNP F/H homologue of Trypanosoma brucei is differentially expressed in the two life cycle stages of the parasite and regulates splicing and mRNA stability. Nucleic Acids Res 2013; 41:6577-94. [PMID: 23666624 PMCID: PMC3711420 DOI: 10.1093/nar/gkt369] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Trypanosomes are protozoan parasites that cycle between a mammalian host (bloodstream form) and an insect host, the Tsetse fly (procyclic stage). In trypanosomes, all mRNAs are trans-spliced as part of their maturation. Genome-wide analysis of trans-splicing indicates the existence of alternative trans-splicing, but little is known regarding RNA-binding proteins that participate in such regulation. In this study, we performed functional analysis of the Trypanosoma brucei heterogeneous nuclear ribonucleoproteins (hnRNP) F/H homologue, a protein known to regulate alternative splicing in metazoa. The hnRNP F/H is highly expressed in the bloodstream form of the parasite, but is also functional in the procyclic form. Transcriptome analyses of RNAi-silenced cells were used to deduce the RNA motif recognized by this protein. A purine rich motif, AAGAA, was enriched in both the regulatory regions flanking the 3′ splice site and poly (A) sites of the regulated genes. The motif was further validated using mini-genes carrying wild-type and mutated sequences in the 3′ and 5′ UTRs, demonstrating the role of hnRNP F/H in mRNA stability and splicing. Biochemical studies confirmed the binding of the protein to this proposed site. The differential expression of the protein and its inverse effects on mRNA level in the two lifecycle stages demonstrate the role of hnRNP F/H in developmental regulation.
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Affiliation(s)
- Sachin Kumar Gupta
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
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Cyphert TJ, Suchanek AL, Griffith BN, Salati LM. Starvation actively inhibits splicing of glucose-6-phosphate dehydrogenase mRNA via a bifunctional ESE/ESS element bound by hnRNP K. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:905-15. [PMID: 23631859 DOI: 10.1016/j.bbagrm.2013.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/17/2013] [Accepted: 04/22/2013] [Indexed: 12/26/2022]
Abstract
Regulated expression of glucose-6-phosphate dehydrogenase (G6PD) is due to changes in the rate of pre-mRNA splicing and not changes in its transcription. Starvation alters pre-mRNA splicing by decreasing the rate of intron removal, leading to intron retention and a decrease in the accumulation of mature mRNA. A regulatory element within exon 12 of G6PD pre-mRNA controls splicing efficiency. Starvation caused an increase in the expression of heterogeneous nuclear ribonucleoprotein (hnRNP) K protein and this increase coincided with the increase in the binding of hnRNP K to the regulatory element and a decrease in the expression of G6PD mRNA. HnRNP K bound to two C-rich motifs forming an ESS within exon 12. Overexpression of hnRNP K decreased the splicing and expression of G6PD mRNA, while siRNA-mediated depletion of hnRNP K caused an increase in the splicing and expression of G6PD mRNA. Binding of hnRNP K to the regulatory element was enhanced in vivo by starvation coinciding with a decrease in G6PD mRNA. HnRNP K binding to the C-rich motifs blocked binding of serine-arginine rich, splicing factor 3 (SRSF3), a splicing enhancer. Thus hnRNP K is a nutrient regulated splicing factor responsible for the inhibition of the splicing of G6PD during starvation.
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Affiliation(s)
- T J Cyphert
- Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
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Turunen JJ, Verma B, Nyman TA, Frilander MJ. HnRNPH1/H2, U1 snRNP, and U11 snRNP cooperate to regulate the stability of the U11-48K pre-mRNA. RNA (NEW YORK, N.Y.) 2013; 19:380-9. [PMID: 23335637 PMCID: PMC3677248 DOI: 10.1261/rna.036715.112] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Alternative splicing (AS) is a major contributor to proteome diversity, but it also regulates gene expression by introducing premature termination codons (PTCs) that destabilize transcripts, typically via the nonsense-mediated decay (NMD) pathway. Such AS events often take place within long, conserved sequence elements, particularly in genes encoding various RNA binding proteins. AS-NMD is often activated by the protein encoded by the same gene, leading to a self-regulating feedback loop that maintains constant protein levels. However, cross-regulation between different RNA binding proteins is also common, giving rise to finely tuned regulatory networks. Recently, we described a feedback mechanism regulating two protein components of the U12-dependent spliceosome (U11-48K and U11/U12-65K) through a highly conserved sequence element. These elements contain a U11 snRNP-binding splicing enhancer (USSE), which, through the U11 snRNP, activates an upstream U2-type 3'ss, resulting in the degradation of the U11-48K mRNA by AS-NMD. Through phylogenetic analysis, we now identify a G-rich sequence element that is conserved in fishes as well as mammals. We show that this element binds hnRNPF/H proteins in vitro. Knockdown of hnRNPH1/H2 or mutations in the G-run both lead to enhanced activation of the 3'ss in vivo, suggesting that hnRNPH1/H2 proteins counteract the 3'ss activation. Furthermore, we provide evidence that U1 binding immediately downstream from the G-run similarly counteracts the U11-mediated activation of the alternative 3'ss. Thus, our results elucidate the mechanism in which snRNPs from both spliceosomes together with hnRNPH1/H2 proteins regulate the recognition and activation of the highly conserved alternative splice sites within the U11-48K pre-mRNA.
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Integrative genome-wide analysis reveals cooperative regulation of alternative splicing by hnRNP proteins. Cell Rep 2013; 1:167-78. [PMID: 22574288 DOI: 10.1016/j.celrep.2012.02.001] [Citation(s) in RCA: 359] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Understanding how RNA binding proteins control the splicing code is fundamental to human biology and disease. Here, we present a comprehensive study to elucidate how heterogeneous nuclear ribonucleoparticle (hnRNP) proteins, among the most abundant RNA binding proteins, coordinate to regulate alternative pre-mRNA splicing (AS) in human cells. Using splicing-sensitive microarrays, crosslinking and immunoprecipitation coupled with high-throughput sequencing (CLIP-seq), and cDNA sequencing, we find that more than half of all AS events are regulated by multiple hnRNP proteins and that some combinations of hnRNP proteins exhibit significant synergy, whereas others act antagonistically. Our analyses reveal position-dependent RNA splicing maps, in vivo consensus binding sites, a surprising level of cross- and autoregulation among hnRNP proteins, and the coordinated regulation by hnRNP proteins of dozens of other RNA binding proteins and genes associated with cancer. Our findings define an unprecedented degree of complexity and compensatory relationships among hnRNP proteins and their splicing targets that likely confer robustness to cells.
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35
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Srirangalingam U, Akker SA, Norman D, Navaratnam N, Chew SL, Khoo B. Multiple tandem splicing silencer elements suppress aberrant splicing within the long exon 26 of the human Apolipoprotein B gene. BMC Mol Biol 2013; 14:5. [PMID: 23391187 PMCID: PMC3640928 DOI: 10.1186/1471-2199-14-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 01/22/2013] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Apolipoprotein B (APOB) is an integral component of the chylomicron and the atherogenic lipoproteins LDL and Lp(a). Exon 26 of the APOB pre-mRNA is unusually long at 7,572 nt and is constitutively spliced. It is also subject to RNA editing in the intestine, which generates a shortened isoform, APOB48, assembled exclusively into chylomicrons. Due to its length, exon 26 contains multiple pseudo splice sites which are not spliced, but which conform to the degenerate splice site consensus. RESULTS We demonstrate that these pseudo splice sites are repressed by multiple, tandem splicing silencers distributed along the length of exon 26. The distribution of these elements appears to be heterogeneous, with a greater frequency in the middle 4,800 nt of the exon. CONCLUSION Repression of these splice sites is key to maintaining the integrity of exon 26 during RNA splicing and therefore the correct expression of both isoforms of APOB.
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Affiliation(s)
- Umasuthan Srirangalingam
- Department of Endocrinology, William Harvey Research Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, UK
| | - Scott A Akker
- Department of Endocrinology, William Harvey Research Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, UK
| | - Dennis Norman
- Department of Endocrinology, William Harvey Research Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, UK
- Current address: Argenta Discovery Ltd, 8/9 Spire Green Centre, Flex Meadow, Harlow, Essex, CM19 5TR, UK
| | - Naveenan Navaratnam
- RNA Editing Group, MRC Clinical Sciences Centre, Division of Clinical Sciences, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Shern L Chew
- Department of Endocrinology, William Harvey Research Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, UK
| | - Bernard Khoo
- Department of Endocrinology, William Harvey Research Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, UK
- Current address: Department of Endocrinology, UCL Medical School, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK
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Erkelenz S, Mueller WF, Evans MS, Busch A, Schöneweis K, Hertel KJ, Schaal H. Position-dependent splicing activation and repression by SR and hnRNP proteins rely on common mechanisms. RNA (NEW YORK, N.Y.) 2013; 19:96-102. [PMID: 23175589 PMCID: PMC3527730 DOI: 10.1261/rna.037044.112] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Alternative splicing is regulated by splicing factors that modulate splice site selection. In some cases, however, splicing factors show antagonistic activities by either activating or repressing splicing. Here, we show that these opposing outcomes are based on their binding location relative to regulated 5' splice sites. SR proteins enhance splicing only when they are recruited to the exon. However, they interfere with splicing by simply relocating them to the opposite intronic side of the splice site. hnRNP splicing factors display analogous opposing activities, but in a reversed position dependence. Activation by SR or hnRNP proteins increases splice site recognition at the earliest steps of exon definition, whereas splicing repression promotes the assembly of nonproductive complexes that arrest spliceosome assembly prior to splice site pairing. Thus, SR and hnRNP splicing factors exploit similar mechanisms to positively or negatively influence splice site selection.
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Affiliation(s)
- Steffen Erkelenz
- Institute of Virology, Heinrich-Heine-University, D-40225 Düsseldorf, Germany
| | - William F. Mueller
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, California 92697-4025, USA
| | - Melanie S. Evans
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, California 92697-4025, USA
| | - Anke Busch
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, California 92697-4025, USA
| | - Katrin Schöneweis
- Institute of Virology, Heinrich-Heine-University, D-40225 Düsseldorf, Germany
| | - Klemens J. Hertel
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, California 92697-4025, USA
- Corresponding authorsE-mail E-mail
| | - Heiner Schaal
- Institute of Virology, Heinrich-Heine-University, D-40225 Düsseldorf, Germany
- Corresponding authorsE-mail E-mail
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Samatanga B, Dominguez C, Jelesarov I, Allain FHT. The high kinetic stability of a G-quadruplex limits hnRNP F qRRM3 binding to G-tract RNA. Nucleic Acids Res 2012; 41:2505-16. [PMID: 23275549 PMCID: PMC3575826 DOI: 10.1093/nar/gks1289] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The RNA binding protein heterogeneous nuclear ribonucleoprotein (hnRNP) F is involved in telomeres maintenance and pre-mRNA processing, such as alternative splicing and polyadenylation. It specifically recognizes RNA containing three consecutive guanines (G-tracts) that have the potential to assemble into G-quadruplexes. We have proposed recently that hnRNP F could regulate alternative splicing by remodeling RNA structures, such as G-quadruplexes. However, the exact mechanism of hnRNP F binding to such RNA sequences remains unknown. Here, we have studied the binding of the third RNA binding domain of hnRNP F [quasi-RNA recognition motif 3 (qRRM3)] to G-tract RNA using isothermal titration calorimetry, circular dichroism and nuclear magnetic resonance spectroscopy. Our results show that qRRM3 binds specifically exclusively to single-stranded G-tracts (ssRNA), in contrast to previous reports stating that the G-quadruplex was recognized as well. Furthermore, we demonstrate that the pre-existent ssRNA/G-quadruplex equilibrium slows down the formation of the protein–ssRNA complex. Based on in vitro transcription assays, we show that the rate of the protein–RNA complex formation is faster than that of the G-quadruplex. We propose a model according to which hnRNP F could bind RNA co-transcriptionally and prevents G-quadruplex formation.
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Affiliation(s)
- Brighton Samatanga
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
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38
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An intronic G run within HIV-1 intron 2 is critical for splicing regulation of vif mRNA. J Virol 2012; 87:2707-20. [PMID: 23255806 DOI: 10.1128/jvi.02755-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Within target T lymphocytes, human immunodeficiency virus type I (HIV-1) encounters the retroviral restriction factor APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G; A3G), which is counteracted by the HIV-1 accessory protein Vif. Vif is encoded by intron-containing viral RNAs that are generated by splicing at 3' splice site (3'ss) A1 but lack splicing at 5'ss D2, which results in the retention of a large downstream intron. Hence, the extents of activation of 3'ss A1 and repression of D2, respectively, determine the levels of vif mRNA and thus the ability to evade A3G-mediated antiviral effects. The use of 3'ss A1 can be enhanced or repressed by splicing regulatory elements that control the recognition of downstream 5'ss D2. Here we show that an intronic G run (G(I2)-1) represses the use of a second 5'ss, termed D2b, that is embedded within intron 2 and, as determined by RNA deep-sequencing analysis, is normally inefficiently used. Mutations of G(I2)-1 and activation of D2b led to the generation of transcripts coding for Gp41 and Rev protein isoforms but primarily led to considerable upregulation of vif mRNA expression. We further demonstrate, however, that higher levels of Vif protein are actually detrimental to viral replication in A3G-expressing T cell lines but not in A3G-deficient cells. These observations suggest that an appropriate ratio of Vif-to-A3G protein levels is required for optimal virus replication and that part of Vif level regulation is effected by the novel G run identified here.
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Wang E, Aslanzadeh V, Papa F, Zhu H, de la Grange P, Cambi F. Global profiling of alternative splicing events and gene expression regulated by hnRNPH/F. PLoS One 2012; 7:e51266. [PMID: 23284676 PMCID: PMC3524136 DOI: 10.1371/journal.pone.0051266] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 10/31/2012] [Indexed: 11/19/2022] Open
Abstract
In this study, we have investigated the global impact of heterogeneous nuclear Ribonuclear Protein (hnRNP) H/F-mediated regulation of splicing events and gene expression in oligodendrocytes. We have performed a genome-wide transcriptomic analysis at the gene and exon levels in Oli-neu cells treated with siRNA that targets hnRNPH/F compared to untreated cells using Affymetrix Exon Array. Gene expression levels and regulated exons were identified with the GenoSplice EASANA algorithm. Bioinformatics analyses were performed to determine the structural properties of G tracts that correlate with the function of hnRNPH/F as enhancers vs. repressors of exon inclusion. Different types of alternatively spliced events are regulated by hnRNPH/F. Intronic G tracts density, length and proximity to the 5′ splice site correlate with the hnRNPH/F enhancer function. Additionally, 6% of genes are differently expressed upon knock down of hnRNPH/F. Genes that regulate the transition of oligodendrocyte progenitor cells to oligodendrocytes are differentially expressed in hnRNPH/F depleted Oli-neu cells, resulting in a decrease of negative regulators and an increase of differentiation-inducing regulators. The changes were confirmed in developing oligodendrocytes in vivo. This is the first genome wide analysis of splicing events and gene expression regulated by hnRNPH/F in oligodendrocytes and the first report that hnRNPH/F regulate genes that are involved in the transition from oligodendrocyte progenitor cells to oligodendrocytes.
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Affiliation(s)
- Erming Wang
- Department of Neurology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Vahid Aslanzadeh
- Department of Biotechnology, Research Institute of Physiology and Biotechnology, University of Zanjan, Zanjan, Iran
| | - Filomena Papa
- Department of Neurology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Haiyan Zhu
- Department of Neurology, University of Kentucky, Lexington, Kentucky, United States of America
| | | | - Franca Cambi
- Department of Neurology, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail:
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Wang Y, Xiao X, Zhang J, Choudhury R, Robertson A, Li K, Ma M, Burge CB, Wang Z. A complex network of factors with overlapping affinities represses splicing through intronic elements. Nat Struct Mol Biol 2012; 20:36-45. [PMID: 23241926 PMCID: PMC3537874 DOI: 10.1038/nsmb.2459] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 11/05/2012] [Indexed: 12/11/2022]
Abstract
To better understand splicing regulation, we used a cell-based screen to identify ten diverse motifs that inhibit splicing from intron. Each motif was validated in another human cell type and gene context, and their presence correlated with in vivo splicing changes. All motifs exhibited exonic splicing enhancer or silencer activity, and grouping these motifs based on their distributions yielded clusters with distinct patterns of context-dependent activity. Candidate regulatory factors associated with each motif were identified, recovering 24 known and novel splicing regulators. Specific domains in selected factors were sufficient to confer ISS activity. Many factors bound multiple distinct motifs with similar affinity, and all motifs were recognized by multiple factors, revealing a complex, overlapping network of protein:RNA interactions. This arrangement enables individual cis-element to function differently in distinct cellular contexts depending on the spectrum of regulatory factors present.
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Affiliation(s)
- Yang Wang
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA
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Ohno G, Ono K, Togo M, Watanabe Y, Ono S, Hagiwara M, Kuroyanagi H. Muscle-specific splicing factors ASD-2 and SUP-12 cooperatively switch alternative pre-mRNA processing patterns of the ADF/cofilin gene in Caenorhabditis elegans. PLoS Genet 2012; 8:e1002991. [PMID: 23071450 PMCID: PMC3469465 DOI: 10.1371/journal.pgen.1002991] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 08/10/2012] [Indexed: 11/18/2022] Open
Abstract
Pre-mRNAs are often processed in complex patterns in tissue-specific manners to produce a variety of protein isoforms from single genes. However, mechanisms orchestrating the processing of the entire transcript are not well understood. Muscle-specific alternative pre-mRNA processing of the unc-60 gene in Caenorhabditis elegans, encoding two tissue-specific isoforms of ADF/cofilin with distinct biochemical properties in regulating actin organization, provides an excellent in vivo model of complex and tissue-specific pre-mRNA processing; it consists of a single first exon and two separate series of downstream exons. Here we visualize the complex muscle-specific processing pattern of the unc-60 pre-mRNA with asymmetric fluorescence reporter minigenes. By disrupting juxtaposed CUAAC repeats and UGUGUG stretch in intron 1A, we demonstrate that these elements are required for retaining intron 1A, as well as for switching the processing patterns of the entire pre-mRNA from non-muscle-type to muscle-type. Mutations in genes encoding muscle-specific RNA-binding proteins ASD-2 and SUP-12 turned the colour of the unc-60 reporter worms. ASD-2 and SUP-12 proteins specifically and cooperatively bind to CUAAC repeats and UGUGUG stretch in intron 1A, respectively, to form a ternary complex in vitro. Immunohistochemical staining and RT-PCR analyses demonstrate that ASD-2 and SUP-12 are also required for switching the processing patterns of the endogenous unc-60 pre-mRNA from UNC-60A to UNC-60B in muscles. Furthermore, systematic analyses of partially spliced RNAs reveal the actual orders of intron removal for distinct mRNA isoforms. Taken together, our results demonstrate that muscle-specific splicing factors ASD-2 and SUP-12 cooperatively promote muscle-specific processing of the unc-60 gene, and provide insight into the mechanisms of complex pre-mRNA processing; combinatorial regulation of a single splice site by two tissue-specific splicing regulators determines the binary fate of the entire transcript.
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Affiliation(s)
- Genta Ohno
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Functional Genomics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- Research Fellowship for Young Scientists, Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Kanako Ono
- Department of Pathology, Emory University, Atlanta, Georgia, United States of America
| | - Marina Togo
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yohei Watanabe
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, Georgia, United States of America
| | - Masatoshi Hagiwara
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Functional Genomics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Functional Genomics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
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Lo CS, Chang SY, Chenier I, Filep JG, Ingelfinger JR, Zhang SL, Chan JS. Heterogeneous nuclear ribonucleoprotein F suppresses angiotensinogen gene expression and attenuates hypertension and kidney injury in diabetic mice. Diabetes 2012; 61:2597-608. [PMID: 22664958 PMCID: PMC3447919 DOI: 10.2337/db11-1349] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We investigated the impact of heterogeneous nuclear ribonucleoprotein F (hnRNP F) overexpression on angiotensinogen (Agt) gene expression, hypertension, and renal proximal tubular cell (RPTC) injury in high-glucose milieu both in vivo and in vitro. Diabetic Akita transgenic (Tg) mice specifically overexpressing hnRNP F in their RPTCs were created, and the effects on systemic hypertension, Agt gene expression, renal hypertrophy, and interstitial fibrosis were studied. We also examined immortalized rat RPTCs stably transfected with control plasmid or plasmid containing hnRNP F cDNA in vitro. The results showed that hnRNP F overexpression attenuated systemic hypertension, suppressed Agt and transforming growth factor-β1 (TGF-β1) gene expression, and reduced urinary Agt and angiotensin II levels, renal hypertrophy, and glomerulotubular fibrosis in Akita hnRNP F-Tg mice. In vitro, hnRNP F overexpression prevented the high-glucose stimulation of Agt and TGF-β1 mRNA expression and cellular hypertrophy in RPTCs. These data suggest that hnRNP F plays a modulatory role and can ameliorate hypertension, renal hypertrophy, and interstitial fibrosis in diabetes. The underlying mechanism is mediated, at least in part, via the suppression of intrarenal Agt gene expression in vivo. hnRNP F may be a potential target in the treatment of hypertension and kidney injury in diabetes.
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Affiliation(s)
- Chao-Sheng Lo
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Université de Montréal, Hôtel-Dieu Hospital, Montreal, Quebec, Canada
| | - Shiao-Ying Chang
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Université de Montréal, Hôtel-Dieu Hospital, Montreal, Quebec, Canada
| | - Isabelle Chenier
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Université de Montréal, Hôtel-Dieu Hospital, Montreal, Quebec, Canada
| | - Janos G. Filep
- Research Centre, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada
| | - Julie R. Ingelfinger
- Pediatric Nephrology Unit, Massachusetts General Hospital, Boston, Massachusetts
| | - Shao Ling Zhang
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Université de Montréal, Hôtel-Dieu Hospital, Montreal, Quebec, Canada
| | - John S.D. Chan
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Université de Montréal, Hôtel-Dieu Hospital, Montreal, Quebec, Canada
- Corresponding author: John S.D. Chan,
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Intronic splicing enhancers, cognate splicing factors and context-dependent regulation rules. Nat Struct Mol Biol 2012; 19:1044-52. [PMID: 22983564 PMCID: PMC3753194 DOI: 10.1038/nsmb.2377] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 08/07/2012] [Indexed: 12/16/2022]
Abstract
Most human genes produce multiple splicing isoforms with distinct functions. To systematically understand splicing regulation, we conducted an unbiased screen and identified >100 intronic splicing enhancers (ISEs) that were clustered by sequence similarity into six groups. All ISEs functioned in another cell type and heterologous introns, and their distribution and conservation patterns in different pre-mRNA regions are similar to exonic splicing silencers. Consistently all ISEs inhibited use of splice sites from exonic locations. The putative trans-factors of each ISE group were identified and validated. Five distinct ISE motifs were recognized by hnRNP H and F whose C-terminal domains were sufficient to render context-dependent activities of ISEs. The sixth group was controlled by factors that either activate or suppress splicing. This work provided a comprehensive picture of general ISE activities and provided new models of how a single element can function oppositely depending on its locations and binding factors.
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Sun S, Zhang Z, Fregoso O, Krainer AR. Mechanisms of activation and repression by the alternative splicing factors RBFOX1/2. RNA (NEW YORK, N.Y.) 2012; 18:274-83. [PMID: 22184459 PMCID: PMC3264914 DOI: 10.1261/rna.030486.111] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 11/09/2011] [Indexed: 05/20/2023]
Abstract
RBFOX1 and RBFOX2 are alternative splicing factors that are predominantly expressed in the brain and skeletal muscle. They specifically bind the RNA element UGCAUG, and regulate alternative splicing positively or negatively in a position-dependent manner. The molecular basis for the position dependence of these and other splicing factors on alternative splicing of their targets is not known. We explored the mechanisms of RBFOX splicing activation and repression using an MS2-tethering assay. We found that the Ala/Tyr/Gly-rich C-terminal domain is sufficient for exon activation when tethered to the downstream intron, whereas both the C-terminal domain and the central RRM are required for exon repression when tethered to the upstream intron. Using immunoprecipitation and mass spectrometry, we identified hnRNP H1, RALY, and TFG as proteins that specifically interact with the C-terminal domain of RBFOX1 and RBFOX2. RNA interference experiments showed that hnRNP H1 and TFG modulate the splicing activity of RBFOX1/2, whereas RALY had no effect. However, TFG is localized in the cytoplasm, and likely modulates alternative splicing indirectly.
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Affiliation(s)
- Shuying Sun
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Zuo Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Oliver Fregoso
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Adrian R. Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
- Corresponding author.E-mail .
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Abstract
The predominate form of DNA diagnostics remains nucleic acid sequencing in the research and clinical setting. While DNA sequencing allows a mutation to be correctly identified, only RNA sequencing can confirm the effect of that mutation on the resulting mRNA transcript. In the absence of RNA sequencing, predictions are reliant on either experimental studies or bioinformatic modelling. While each of these approaches provides insights into cellular splicing choices, of which exon skipping is but one, both possess inherent weaknesses. A method which is able to integrate and appropriately weigh the various factors influencing cellular splicing choices into an accurate, comprehensive modelling tool still remains elusive.In this overview chapter, the current methods utilised for DNA diagnostics and the impact of the emerging next-generation sequencing techniques are considered. We explore why RNA remains a problematic medium with which to work. To understand how exon skipping can be predicted from a DNA sequence, the key cis-acting elements influencing splicing are reviewed. Finally, the current methods used to predict exon skipping including RNA-based studies, experimental studies, and bioinformatic modelling approaches are outlined.
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Splicing factor hnRNPH drives an oncogenic splicing switch in gliomas. EMBO J 2011; 30:4084-97. [PMID: 21915099 PMCID: PMC3209773 DOI: 10.1038/emboj.2011.259] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 07/05/2011] [Indexed: 12/11/2022] Open
Abstract
This study reveals two alternative splicing events that contribute to the development of glioma. HnRNPH is shown to control production of a pro-survival splice variant of the death-domain adaptor protein IG20-MADD and the motility-enhancing isoform of the RON receptor tyrosine kinase. In tumours, aberrant splicing generates variants that contribute to multiple aspects of tumour establishment, progression and maintenance. We show that in glioblastoma multiforme (GBM) specimens, death-domain adaptor protein Insuloma-Glucagonoma protein 20 (IG20) is consistently aberrantly spliced to generate an antagonist, anti-apoptotic isoform (MAP-kinase activating death domain protein, MADD), which effectively redirects TNF-α/TRAIL-induced death signalling to promote survival and proliferation instead of triggering apoptosis. Splicing factor hnRNPH, which is upregulated in gliomas, controls this splicing event and similarly mediates switching to a ligand-independent, constitutively active Recepteur d′Origine Nantais (RON) tyrosine kinase receptor variant that promotes migration and invasion. The increased cell death and the reduced invasiveness caused by hnRNPH ablation can be rescued by the targeted downregulation of IG20/MADD exon 16- or RON exon 11-containing variants, respectively, using isoform-specific knockdown or splicing redirection approaches. Thus, hnRNPH activity appears to be involved in the pathogenesis and progression of malignant gliomas as the centre of a splicing oncogenic switch, which might reflect reactivation of stem cell patterns and mediates multiple key aspects of aggressive tumour behaviour, including evasion from apoptosis and invasiveness.
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Interaction between the RNA binding domains of Ser-Arg splicing factor 1 and U1-70K snRNP protein determines early spliceosome assembly. Proc Natl Acad Sci U S A 2011; 108:8233-8. [PMID: 21536904 DOI: 10.1073/pnas.1017700108] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been widely accepted that the early spliceosome assembly begins with U1 small nuclear ribonucleoprotein (U1 snRNP) binding to the 5' splice site (5'SS), which is assisted by the Ser/Arg (SR)-rich proteins in mammalian cells. In this process, the RS domain of SR proteins is thought to directly interact with the RS motif of U1-70K, which is subject to regulation by RS domain phosphorylation. Here we report that the early spliceosome assembly event is mediated by the RNA recognition domains (RRM) of serine/arginine-rich splicing factor 1 (SRSF1), which bridges the RRM of U1-70K to pre-mRNA by using the surface opposite to the RNA binding site. Specific mutation in the RRM of SRSF1 that disrupted the RRM-RRM interaction also inhibits the formation of spliceosomal E complex and splicing. We further demonstrate that the hypo-phosphorylated RS domain of SRSF1 interacts with its own RRM, thus competing with U1-70K binding, whereas the hyper-phosphorylated RS domain permits the formation of a ternary complex containing ESE, an SR protein, and U1 snRNP. Therefore, phosphorylation of the RS domain in SRSF1 appears to induce a key molecular switch from intra- to intermolecular interactions, suggesting a plausible mechanism for the documented requirement for the phosphorylation/dephosphorylation cycle during pre-mRNA splicing.
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48
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Ke S, Chasin LA. Context-dependent splicing regulation: exon definition, co-occurring motif pairs and tissue specificity. RNA Biol 2011; 8:384-8. [PMID: 21444999 DOI: 10.4161/rna.8.3.14458] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Splicing is a crucial process in gene expression in higher organisms because: 1) most vertebrate genes contain introns; and 2) alternative splicing is primarily responsible for increasing proteomic complexity and functional diversity. Intron definition, the coordination across an intron, is a mandatory step in the splicing process. However, exon definition, the coordination across an exon, is also thought to be required for the splicing of most vertebrate exons. Recent investigations of exon definition complexes provide insights into splicing dynamics. That splicing regulators act in a context-dependent mode is supported by a large collection of evidence. Splicing contexts generally can be classified as cis-element and trans-element contexts. A widespread cis-element context is defined by co-occurring motif pairs to which splicing regulatory factors bind to direct specific molecular interactions. Splicing regulation is also coordinated by trans-element contexts as exemplified by tissue specific splicing, where alternative exons can be coordinately regulated by a few splicing factors, the expression and/or activity of which are concertedly higher or lower in the corresponding tissues.
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Affiliation(s)
- Shengdong Ke
- Department of Biological Sciences, Columbia University, New York, NY, USA
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49
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Llorian M, Smith CWJ. Decoding muscle alternative splicing. Curr Opin Genet Dev 2011; 21:380-7. [PMID: 21514141 DOI: 10.1016/j.gde.2011.03.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 03/25/2011] [Indexed: 01/15/2023]
Abstract
Muscle was one of the first tissues in which alternative splicing was widely observed. Cloning and sequencing of muscle-derived cDNAs in the early 1980's revealed that many of the abundant contractile proteins arise by alternative splicing of genes that are more widely expressed. Consequently alternative splicing events in contractile protein genes have long been used as models to dissect the mechanisms of alternative splicing. Transcriptomic and computational analyses have complemented traditional molecular analyses of alternative splicing in muscle and other tissues, illuminating the general underlying principles of coregulated splicing programs. This has culminated in the first attempt to computationally predict tissue-specific changes in splicing. Investigations of myotonic dystrophy (DM), in which CUG expansion RNA leads to misregulated splicing in muscle, have enhanced our understanding of developmentally regulated splicing and led to the development of promising therapeutic strategies based on targeting the toxic RNA repeats.
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Affiliation(s)
- Miriam Llorian
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
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50
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Xiao X, Lee JH. Systems analysis of alternative splicing and its regulation. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 2:550-565. [PMID: 20836047 DOI: 10.1002/wsbm.84] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Alternative splicing (AS) has emerged as a key mechanism that accounts for gene expression diversity in metazoan organisms. Splicing is tightly regulated by a repertoire of RNA and protein factors and RNA sequence elements that function in a cooperative manner. Systems-level experimental and computational approaches have been instrumental in establishing comprehensive profiles of transcript variants generated by AS. In addition, systems biology approaches are starting to define how combinatorial splicing regulation shapes the complex splicing phenotypes observed in different tissue types and developmental stages and under different conditions. Here, we review recent progress in these areas.
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Affiliation(s)
- Xinshu Xiao
- Department of Physiological Science, University of California, Los Angeles, CA 90095, USA.,Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Jae-Hyung Lee
- Department of Physiological Science, University of California, Los Angeles, CA 90095, USA.,Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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