201
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Uzor S, Zorzou P, Bowler E, Porazinski S, Wilson I, Ladomery M. Autoregulation of the human splice factor kinase CLK1 through exon skipping and intron retention. Gene 2018; 670:46-54. [PMID: 29802995 DOI: 10.1016/j.gene.2018.05.095] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/16/2018] [Accepted: 05/23/2018] [Indexed: 01/04/2023]
Abstract
Alternative splicing is a key process required for the regulation of gene expression in normal development and physiology. It is regulated by splice factors whose activities are in turn regulated by splice factor kinases and phosphatases. The CDC-like protein kinases are a widespread family of splice factor kinases involved in normal physiology and in several diseases including cancer. In humans they include the CLK1, CLK2, CLK3 and CLK4 genes. The expression of CLK1 is regulated through alternative splicing producing both full-length catalytically active and truncated catalytically inactive isoforms, CLKT1 (arising from exon 4 skipping) and CLKT2 (arising from intron 4 retention). We examined CLK1 alternative splicing in a range of cancer cell lines, and report widespread and highly variable rates of exon 4 skipping and intron 4 retention. We also examined the effect of severe environmental stress including heat shock, osmotic shock, and exposure to the alkaloid drug harmine on CLK1 alternative splicing in DU145 prostate cancer cells. All treatments rapidly reduced exon 4 skipping and intron 4 retention, shifting the balance towards full-length CLK1 expression. We also found that the inhibition of CLK1 with the benzothiazole TG003 reduced exon 4 skipping and intron 4 retention suggesting an autoregulatory mechanism. CLK1 inhibition with TG003 also resulted in modified alternative splicing of five cancer-associated genes.
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Affiliation(s)
- Simon Uzor
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, United Kingdom
| | - Panagiota Zorzou
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, United Kingdom
| | - Elizabeth Bowler
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, United Kingdom
| | - Sean Porazinski
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, United Kingdom
| | - Ian Wilson
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, United Kingdom
| | - Michael Ladomery
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, United Kingdom.
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202
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Hansen MMK, Wen WY, Ingerman E, Razooky BS, Thompson CE, Dar RD, Chin CW, Simpson ML, Weinberger LS. A Post-Transcriptional Feedback Mechanism for Noise Suppression and Fate Stabilization. Cell 2018; 173:1609-1621.e15. [PMID: 29754821 PMCID: PMC6044448 DOI: 10.1016/j.cell.2018.04.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/19/2018] [Accepted: 04/03/2018] [Indexed: 11/25/2022]
Abstract
Diverse biological systems utilize fluctuations ("noise") in gene expression to drive lineage-commitment decisions. However, once a commitment is made, noise becomes detrimental to reliable function, and the mechanisms enabling post-commitment noise suppression are unclear. Here, we find that architectural constraints on noise suppression are overcome to stabilize fate commitment. Using single-molecule and time-lapse imaging, we find that-after a noise-driven event-human immunodeficiency virus (HIV) strongly attenuates expression noise through a non-transcriptional negative-feedback circuit. Feedback is established through a serial cascade of post-transcriptional splicing, whereby proteins generated from spliced mRNAs auto-deplete their own precursor unspliced mRNAs. Strikingly, this auto-depletion circuitry minimizes noise to stabilize HIV's commitment decision, and a noise-suppression molecule promotes stabilization. This feedback mechanism for noise suppression suggests a functional role for delayed splicing in other systems and may represent a generalizable architecture of diverse homeostatic signaling circuits.
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Affiliation(s)
- Maike M K Hansen
- Gladstone
- UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Winnie Y Wen
- Gladstone
- UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Elena Ingerman
- Gladstone
- UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Brandon S Razooky
- Gladstone
- UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Cassandra E Thompson
- Gladstone
- UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Roy D Dar
- Gladstone
- UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Charles W Chin
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; The Bredesen Center, University of Tennessee, Knoxville, TN 37996, USA
| | - Michael L Simpson
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; The Bredesen Center, University of Tennessee, Knoxville, TN 37996, USA
| | - Leor S Weinberger
- Gladstone
- UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA.
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203
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Ratnadiwakara M, Archer SK, Dent CI, Ruiz De Los Mozos I, Beilharz TH, Knaupp AS, Nefzger CM, Polo JM, Anko ML. SRSF3 promotes pluripotency through Nanog mRNA export and coordination of the pluripotency gene expression program. eLife 2018; 7:37419. [PMID: 29741478 PMCID: PMC5963917 DOI: 10.7554/elife.37419] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/05/2018] [Indexed: 12/28/2022] Open
Abstract
The establishment and maintenance of pluripotency depend on precise coordination of gene expression. We establish serine-arginine-rich splicing factor 3 (SRSF3) as an essential regulator of RNAs encoding key components of the mouse pluripotency circuitry, SRSF3 ablation resulting in the loss of pluripotency and its overexpression enhancing reprogramming. Strikingly, SRSF3 binds to the core pluripotency transcription factor Nanog mRNA to facilitate its nucleo-cytoplasmic export independent of splicing. In the absence of SRSF3 binding, Nanog mRNA is sequestered in the nucleus and protein levels are severely downregulated. Moreover, SRSF3 controls the alternative splicing of the export factor Nxf1 and RNA regulators with established roles in pluripotency, and the steady-state levels of mRNAs encoding chromatin modifiers. Our investigation links molecular events to cellular functions by demonstrating how SRSF3 regulates the pluripotency genes and uncovers SRSF3-RNA interactions as a critical means to coordinate gene expression during reprogramming, stem cell self-renewal and early development.
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Affiliation(s)
- Madara Ratnadiwakara
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Stuart K Archer
- Bioinformatics Platform, Monash University, Clayton, Australia
| | - Craig I Dent
- School of Biological Sciences, Monash University, Melbourne, Australia
| | | | - Traude H Beilharz
- Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Anja S Knaupp
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Christian M Nefzger
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Jose M Polo
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Minna-Liisa Anko
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
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204
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Tatomer DC, Liang D, Wilusz JE. Inducible Expression of Eukaryotic Circular RNAs from Plasmids. Methods Mol Biol 2018; 1648:143-154. [PMID: 28766295 DOI: 10.1007/978-1-4939-7204-3_11] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Thousands of eukaryotic protein-coding genes are noncanonically spliced to generate circular RNAs. Because they have covalently linked ends, circular RNAs are resistant to degradation by exonucleases and some accumulate to higher levels than their associated linear mRNAs. The functions of most circular RNAs are still unknown, but recent work has revealed key insights into how the pre-mRNA splicing machinery catalyzes backsplicing. Exons that circularize are often flanked by intronic repeat sequences that are complementary to one another, and backsplicing is triggered when these repeats base pair and bring the intervening splice sites into close proximity. Here, we describe how this knowledge has been translated into a simple plasmid-based method for ectopically expressing circular RNAs in eukaryotic cells. The sequence of interest is cloned into an artificial exon that is flanked by complementary intronic repeats. The plasmid is then transfected into cells, transcription is induced, and the cellular splicing machinery generates the desired circular RNA. Total RNA is isolated and the efficiency/specificity of circular RNA biogenesis is validated by Northern blot analysis. Beyond allowing overexpression of natural circular RNAs to define their functions, this approach can be used to produce designer RNA circles that are translated or bind specific cellular factors, such as microRNAs or proteins.
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Affiliation(s)
- Deirdre C Tatomer
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, 363 Clinical Research Building, 415 Curie Blvd., Philadelphia, PA, 19104, USA
| | - Dongming Liang
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, 363 Clinical Research Building, 415 Curie Blvd., Philadelphia, PA, 19104, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, 363 Clinical Research Building, 415 Curie Blvd., Philadelphia, PA, 19104, USA.
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205
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Park SK, Zhou X, Pendleton KE, Hunter OV, Kohler JJ, O'Donnell KA, Conrad NK. A Conserved Splicing Silencer Dynamically Regulates O-GlcNAc Transferase Intron Retention and O-GlcNAc Homeostasis. Cell Rep 2018; 20:1088-1099. [PMID: 28768194 PMCID: PMC5588854 DOI: 10.1016/j.celrep.2017.07.017] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/11/2017] [Accepted: 07/10/2017] [Indexed: 11/05/2022] Open
Abstract
Modification of nucleocytoplasmic proteins with O-GlcNAc regulates a wide variety of cellular processes and has been linked to human diseases. The enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) add and remove O-GlcNAc, but the mechanisms regulating their expression remain unclear. Here, we demonstrate that retention of the fourth intron of OGT is regulated in response to O-GlcNAc levels. We further define a conserved intronic splicing silencer (ISS) that is necessary for OGT intron retention. Deletion of the ISS in colon cancer cells leads to increases in OGT, but O-GlcNAc homeostasis is maintained by concomitant increases in OGA protein. However, the ISS-deleted cells are hypersensitive to OGA inhibition in culture and in soft agar. Moreover, growth of xenograft tumors from ISS-deleted cells is compromised in mice treated with an OGA inhibitor. Thus, ISS-mediated regulation of OGT intron retention is a key component in OGT expression and maintaining O-GlcNAc homeostasis.
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Affiliation(s)
- Sung-Kyun Park
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xiaorong Zhou
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kathryn E Pendleton
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Olga V Hunter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jennifer J Kohler
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kathryn A O'Donnell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Nicholas K Conrad
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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206
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Intron retention induced by microsatellite expansions as a disease biomarker. Proc Natl Acad Sci U S A 2018; 115:4234-4239. [PMID: 29610297 DOI: 10.1073/pnas.1716617115] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Expansions of simple sequence repeats, or microsatellites, have been linked to ∼30 neurological-neuromuscular diseases. While these expansions occur in coding and noncoding regions, microsatellite sequence and repeat length diversity is more prominent in introns with eight different trinucleotide to hexanucleotide repeats, causing hereditary diseases such as myotonic dystrophy type 2 (DM2), Fuchs endothelial corneal dystrophy (FECD), and C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). Here, we test the hypothesis that these GC-rich intronic microsatellite expansions selectively trigger host intron retention (IR). Using DM2, FECD, and C9-ALS/FTD as examples, we demonstrate that retention is readily detectable in affected tissues and peripheral blood lymphocytes and conclude that IR screening constitutes a rapid and inexpensive biomarker for intronic repeat expansion disease.
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207
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Michelini F, Jalihal AP, Francia S, Meers C, Neeb ZT, Rossiello F, Gioia U, Aguado J, Jones-Weinert C, Luke B, Biamonti G, Nowacki M, Storici F, Carninci P, Walter NG, d'Adda di Fagagna F. From "Cellular" RNA to "Smart" RNA: Multiple Roles of RNA in Genome Stability and Beyond. Chem Rev 2018; 118:4365-4403. [PMID: 29600857 DOI: 10.1021/acs.chemrev.7b00487] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Coding for proteins has been considered the main function of RNA since the "central dogma" of biology was proposed. The discovery of noncoding transcripts shed light on additional roles of RNA, ranging from the support of polypeptide synthesis, to the assembly of subnuclear structures, to gene expression modulation. Cellular RNA has therefore been recognized as a central player in often unanticipated biological processes, including genomic stability. This ever-expanding list of functions inspired us to think of RNA as a "smart" phone, which has replaced the older obsolete "cellular" phone. In this review, we summarize the last two decades of advances in research on the interface between RNA biology and genome stability. We start with an account of the emergence of noncoding RNA, and then we discuss the involvement of RNA in DNA damage signaling and repair, telomere maintenance, and genomic rearrangements. We continue with the depiction of single-molecule RNA detection techniques, and we conclude by illustrating the possibilities of RNA modulation in hopes of creating or improving new therapies. The widespread biological functions of RNA have made this molecule a reoccurring theme in basic and translational research, warranting it the transcendence from classically studied "cellular" RNA to "smart" RNA.
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Affiliation(s)
- Flavia Michelini
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy
| | - Ameya P Jalihal
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Sofia Francia
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy.,Istituto di Genetica Molecolare , CNR - Consiglio Nazionale delle Ricerche , Pavia , 27100 , Italy
| | - Chance Meers
- School of Biological Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Zachary T Neeb
- Institute of Cell Biology , University of Bern , Baltzerstrasse 4 , 3012 Bern , Switzerland
| | | | - Ubaldo Gioia
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy
| | - Julio Aguado
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy
| | | | - Brian Luke
- Institute of Developmental Biology and Neurobiology , Johannes Gutenberg University , 55099 Mainz , Germany.,Institute of Molecular Biology (IMB) , 55128 Mainz , Germany
| | - Giuseppe Biamonti
- Istituto di Genetica Molecolare , CNR - Consiglio Nazionale delle Ricerche , Pavia , 27100 , Italy
| | - Mariusz Nowacki
- Institute of Cell Biology , University of Bern , Baltzerstrasse 4 , 3012 Bern , Switzerland
| | - Francesca Storici
- School of Biological Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Piero Carninci
- RIKEN Center for Life Science Technologies , 1-7-22 Suehiro-cho, Tsurumi-ku , Yokohama City , Kanagawa 230-0045 , Japan
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Fabrizio d'Adda di Fagagna
- IFOM - The FIRC Institute of Molecular Oncology , Milan , 20139 , Italy.,Istituto di Genetica Molecolare , CNR - Consiglio Nazionale delle Ricerche , Pavia , 27100 , Italy
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208
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Rekosh D, Hammarskjold ML. Intron retention in viruses and cellular genes: Detention, border controls and passports. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1470. [PMID: 29508942 DOI: 10.1002/wrna.1470] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/04/2018] [Accepted: 01/24/2018] [Indexed: 02/06/2023]
Abstract
Intron retention (IR), where one or more introns remain in the RNA after splicing, was long thought to be rare in mammalian cells, albeit common in plants and some viruses. Largely due to the development of better methods for RNA analysis, it has now been recognized that IR is much more common than previously thought and that this mechanism is likely to play an important role in mammalian gene regulation. To date, most publications and reviews about IR have described the resulting mRNAs as "dead end" products, with no direct consequence for the proteome. However, there are also many reports of mRNAs with retained introns giving rise to alternative protein isoforms. Although this was originally revealed in viral systems, there are now numerous examples of bona fide cellular proteins that are translated from mRNAs with retained introns. These new isoforms have sometimes been shown to have important regulatory functions. In this review, we highlight recent developments in this area and the research on viruses that led the way to the realization of the many ways in which mRNAs with retained introns can be regulated. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Processing > Splicing Regulation/Alternative Splicing RNA Export and Localization > Nuclear Export/Import RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- David Rekosh
- The Myles H. Thaler Center for AIDS and Human Retrovirus Research and the Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia.,Department of Microbiology, University of Venda, Thohoyandou, South Africa
| | - Marie-Louise Hammarskjold
- The Myles H. Thaler Center for AIDS and Human Retrovirus Research and the Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia.,Department of Microbiology, University of Venda, Thohoyandou, South Africa
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209
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Vanichkina DP, Schmitz U, Wong JJL, Rasko JE. Challenges in defining the role of intron retention in normal biology and disease. Semin Cell Dev Biol 2018; 75:40-49. [DOI: 10.1016/j.semcdb.2017.07.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/19/2017] [Accepted: 07/19/2017] [Indexed: 10/19/2022]
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210
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Physiological and Pathological Function of Serine/Arginine-Rich Splicing Factor 4 and Related Diseases. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3819719. [PMID: 29789787 PMCID: PMC5896335 DOI: 10.1155/2018/3819719] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 01/03/2018] [Accepted: 01/17/2018] [Indexed: 01/06/2023]
Abstract
Serine/arginine-rich splicing factors (SRSFs) have one or two RNA recognition motifs in the N terminal and a serine/arginine-enriched domain in the C terminal. SRSFs are essential components of spliceosomes and are involved in alternative splicing, spliceosome assembly, mRNA export, and nonsense-mediated mRNA decay. The maintenance of cellular and tissue homeostasis relies on accurate alternative splicing, and various patterns of abnormal alternative splicing can cause different diseases. SRSF4 is associated with many physiological and pathological processes and has applications in the diagnosis and prognosis of specific diseases. In this review, we discuss knowledge of SRSF4 in physiological and pathological processes and highlight the applications of SRSF4 in the regulation of gene expression and associated diseases.
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211
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Murphy PA, Butty VL, Boutz PL, Begum S, Kimble AL, Sharp PA, Burge CB, Hynes RO. Alternative RNA splicing in the endothelium mediated in part by Rbfox2 regulates the arterial response to low flow. eLife 2018; 7:29494. [PMID: 29293084 PMCID: PMC5771670 DOI: 10.7554/elife.29494] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/30/2017] [Indexed: 12/13/2022] Open
Abstract
Low and disturbed blood flow drives the progression of arterial diseases including atherosclerosis and aneurysms. The endothelial response to flow and its interactions with recruited platelets and leukocytes determine disease progression. Here, we report widespread changes in alternative splicing of pre-mRNA in the flow-activated murine arterial endothelium in vivo. Alternative splicing was suppressed by depletion of platelets and macrophages recruited to the arterial endothelium under low and disturbed flow. Binding motifs for the Rbfox-family are enriched adjacent to many of the regulated exons. Endothelial deletion of Rbfox2, the only family member expressed in arterial endothelium, suppresses a subset of the changes in transcription and RNA splicing induced by low flow. Our data reveal an alternative splicing program activated by Rbfox2 in the endothelium on recruitment of platelets and macrophages and demonstrate its relevance in transcriptional responses during flow-driven vascular inflammation.
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Affiliation(s)
- Patrick A Murphy
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States
| | | | - Paul L Boutz
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States
| | - Shahinoor Begum
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States.,Howard Hughes Medical Institute, United States
| | - Amy L Kimble
- Center for Vascular Biology, UCONN Health, Farmington, United States
| | - Phillip A Sharp
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States.,Department of Biology, MIT, Cambridge, United States
| | | | - Richard O Hynes
- Koch Institute for Integrative Cancer Research, MIT, Cambridge, United States.,Department of Biology, MIT, Cambridge, United States.,Howard Hughes Medical Institute, United States
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212
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Wegener M, Müller-McNicoll M. Nuclear retention of mRNAs - quality control, gene regulation and human disease. Semin Cell Dev Biol 2017; 79:131-142. [PMID: 29102717 DOI: 10.1016/j.semcdb.2017.11.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 12/21/2022]
Abstract
Nuclear retention of incompletely spliced or mature mRNAs emerges as a novel, previously underappreciated layer of gene regulation, which enables the cell to rapidly respond to stress, viral infection, differentiation cues or changing environmental conditions. Focusing on mammalian cells, we discuss recent insights into the mechanisms and functions of nuclear retention, describe retention-promoting features in protein-coding transcripts and propose mechanisms for their regulated release into the cytoplasm. Moreover, we discuss examples of how aberrant nuclear retention of mRNAs may lead to human diseases.
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Affiliation(s)
- Marius Wegener
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany.
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213
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Schmitz U, Pinello N, Jia F, Alasmari S, Ritchie W, Keightley MC, Shini S, Lieschke GJ, Wong JJL, Rasko JEJ. Intron retention enhances gene regulatory complexity in vertebrates. Genome Biol 2017; 18:216. [PMID: 29141666 PMCID: PMC5688624 DOI: 10.1186/s13059-017-1339-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 10/13/2017] [Indexed: 01/22/2023] Open
Abstract
Background While intron retention (IR) is now widely accepted as an important mechanism of mammalian gene expression control, it remains the least studied form of alternative splicing. To delineate conserved features of IR, we performed an exhaustive phylogenetic analysis in a highly purified and functionally defined cell type comprising neutrophilic granulocytes from five vertebrate species spanning 430 million years of evolution. Results Our RNA-sequencing-based analysis suggests that IR increases gene regulatory complexity, which is indicated by a strong anti-correlation between the number of genes affected by IR and the number of protein-coding genes in the genome of individual species. Our results confirm that IR affects many orthologous or functionally related genes in granulocytes. Further analysis uncovers new and unanticipated conserved characteristics of intron-retaining transcripts. We find that intron-retaining genes are transcriptionally co-regulated from bidirectional promoters. Intron-retaining genes have significantly longer 3′ UTR sequences, with a corresponding increase in microRNA binding sites, some of which include highly conserved sequence motifs. This suggests that intron-retaining genes are highly regulated post-transcriptionally. Conclusions Our study provides unique insights concerning the role of IR as a robust and evolutionarily conserved mechanism of gene expression regulation. Our findings enhance our understanding of gene regulatory complexity by adding another contributor to evolutionary adaptation. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1339-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ulf Schmitz
- Gene & Stem Cell Therapy Program, Centenary Institute, University of Sydney, Camperdown, 2050, NSW, Australia.,Sydney Medical School, University of Sydney, Camperdown, 2050, NSW, Australia
| | - Natalia Pinello
- Gene & Stem Cell Therapy Program, Centenary Institute, University of Sydney, Camperdown, 2050, NSW, Australia.,Sydney Medical School, University of Sydney, Camperdown, 2050, NSW, Australia.,Gene Regulation in Cancer Laboratory, Centenary Institute, University of Sydney, Camperdown, 2050, NSW, Australia
| | - Fangzhi Jia
- Gene & Stem Cell Therapy Program, Centenary Institute, University of Sydney, Camperdown, 2050, NSW, Australia.,Sydney Medical School, University of Sydney, Camperdown, 2050, NSW, Australia
| | - Sultan Alasmari
- Australian Regenerative Medicine Institute, Monash University, Clayton, 3800, VIC, Australia
| | | | | | - Shaniko Shini
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Graham J Lieschke
- Australian Regenerative Medicine Institute, Monash University, Clayton, 3800, VIC, Australia
| | - Justin J-L Wong
- Gene & Stem Cell Therapy Program, Centenary Institute, University of Sydney, Camperdown, 2050, NSW, Australia.,Sydney Medical School, University of Sydney, Camperdown, 2050, NSW, Australia.,Gene Regulation in Cancer Laboratory, Centenary Institute, University of Sydney, Camperdown, 2050, NSW, Australia
| | - John E J Rasko
- Gene & Stem Cell Therapy Program, Centenary Institute, University of Sydney, Camperdown, 2050, NSW, Australia. .,Sydney Medical School, University of Sydney, Camperdown, 2050, NSW, Australia. .,Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, 2050, NSW, Australia. .,, Locked Bag 6, Newtown, NSW, 2042, Australia.
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214
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Auboeuf D. Alternative mRNA processing sites decrease genetic variability while increasing functional diversity. Transcription 2017; 9:75-87. [PMID: 29099315 PMCID: PMC5834221 DOI: 10.1080/21541264.2017.1373891] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Recent large-scale RNA sequencing efforts have revealed the extensive diversity of mRNA molecules produced from most eukaryotic coding genes, which arises from the usage of alternative, cryptic or non-canonical splicing and intronic polyadenylation sites. The prevailing view regarding the tremendous diversity of coding gene transcripts is that mRNA processing is a flexible and more-or-less noisy process leading to a diversity of proteins on which natural selection can act depending on protein-mediated cellular functions. However, this concept raises two main questions. First, do alternative mRNA processing pathways have a role other than generating mRNA and protein diversity? Second, is the cellular function of mRNA variants restricted to the biogenesis of functional protein isoforms? Here, I propose that the co-transcriptional use of alternative mRNA processing sites allows first, the resolution of co-transcriptional biophysical constraints that may otherwise result in DNA instability, and second, increases the diversity of cellular functions of mRNAs in a manner that is not restricted to protein synthesis.
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Affiliation(s)
- Didier Auboeuf
- a Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, Laboratory of Biology and Modelling of the Cell , 46 Allée d'Italie Site Jacques Monod, Lyon , France
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215
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Chen C, Gao S, Sun Q, Tang Y, Han Y, Zhang J, Li Z. Induced splice site mutation generates alternative intron splicing in starch synthase II ( SSII) gene in rice. BIOTECHNOL BIOTEC EQ 2017. [DOI: 10.1080/13102818.2017.1370984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Chao Chen
- The Laboratory of Vector Biology and Control, Department of Biotechnology, College of Engineering, Beijing Normal University (Zhuhai), Zhuhai, P.R. China
| | - Shan Gao
- The Laboratory of Vector Biology and Control, Department of Biotechnology, College of Engineering, Beijing Normal University (Zhuhai), Zhuhai, P.R. China
| | - Qing Sun
- The Laboratory of Vector Biology and Control, Department of Biotechnology, College of Engineering, Beijing Normal University (Zhuhai), Zhuhai, P.R. China
| | - Yuling Tang
- The Laboratory of Vector Biology and Control, Department of Biotechnology, College of Engineering, Beijing Normal University (Zhuhai), Zhuhai, P.R. China
| | - Yuhao Han
- The Laboratory of Vector Biology and Control, Department of Biotechnology, College of Engineering, Beijing Normal University (Zhuhai), Zhuhai, P.R. China
| | - Jinkun Zhang
- The Laboratory of Vector Biology and Control, Department of Biotechnology, College of Engineering, Beijing Normal University (Zhuhai), Zhuhai, P.R. China
| | - Zhipeng Li
- The Laboratory of Vector Biology and Control, Department of Biotechnology, College of Engineering, Beijing Normal University (Zhuhai), Zhuhai, P.R. China
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216
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Brugiolo M, Botti V, Liu N, Müller-McNicoll M, Neugebauer KM. Fractionation iCLIP detects persistent SR protein binding to conserved, retained introns in chromatin, nucleoplasm and cytoplasm. Nucleic Acids Res 2017; 45:10452-10465. [PMID: 28977534 PMCID: PMC5737842 DOI: 10.1093/nar/gkx671] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 07/20/2017] [Indexed: 01/25/2023] Open
Abstract
RNA binding proteins (RBPs) regulate the lives of all RNAs from transcription, processing, and function to decay. How RNA-protein interactions change over time and space to support these roles is poorly understood. Towards this end, we sought to determine how two SR proteins-SRSF3 and SRSF7, regulators of pre-mRNA splicing, nuclear export and translation-interact with RNA in different cellular compartments. To do so, we developed Fractionation iCLIP (Fr-iCLIP), in which chromatin, nucleoplasmic and cytoplasmic fractions are prepared from UV-crosslinked cells and then subjected to iCLIP. As expected, SRSF3 and SRSF7 targets were detected in all fractions, with intron, snoRNA and lncRNA interactions enriched in the nucleus. Cytoplasmically-bound mRNAs reflected distinct functional groupings, suggesting coordinated translation regulation. Surprisingly, hundreds of cytoplasmic intron targets were detected. These cytoplasmic introns were found to be highly conserved and introduced premature termination codons into coding regions. However, many intron-retained mRNAs were not substrates for nonsense-mediated decay (NMD), even though they were detected in polysomes. These findings suggest that intron-retained mRNAs in the cytoplasm have previously uncharacterized functions and/or escape surveillance. Hence, Fr-iCLIP detects the cellular location of RNA-protein interactions and provides insight into co-transcriptional, post-transcriptional and cytoplasmic RBP functions for coding and non-coding RNAs.
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Affiliation(s)
- Mattia Brugiolo
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Na Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe-University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
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217
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Saudemont B, Popa A, Parmley JL, Rocher V, Blugeon C, Necsulea A, Meyer E, Duret L. The fitness cost of mis-splicing is the main determinant of alternative splicing patterns. Genome Biol 2017; 18:208. [PMID: 29084568 PMCID: PMC5663052 DOI: 10.1186/s13059-017-1344-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 10/09/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Most eukaryotic genes are subject to alternative splicing (AS), which may contribute to the production of protein variants or to the regulation of gene expression via nonsense-mediated messenger RNA (mRNA) decay (NMD). However, a fraction of splice variants might correspond to spurious transcripts and the question of the relative proportion of splicing errors to functional splice variants remains highly debated. RESULTS We propose a test to quantify the fraction of AS events corresponding to errors. This test is based on the fact that the fitness cost of splicing errors increases with the number of introns in a gene and with expression level. We analyzed the transcriptome of the intron-rich eukaryote Paramecium tetraurelia. We show that in both normal and in NMD-deficient cells, AS rates strongly decrease with increasing expression level and with increasing number of introns. This relationship is observed for AS events that are detectable by NMD as well as for those that are not, which invalidates the hypothesis of a link with the regulation of gene expression. Our results show that in genes with a median expression level, 92-98% of observed splice variants correspond to errors. We observed the same patterns in human transcriptomes and we further show that AS rates correlate with the fitness cost of splicing errors. CONCLUSIONS These observations indicate that genes under weaker selective pressure accumulate more maladaptive substitutions and are more prone to splicing errors. Thus, to a large extent, patterns of gene expression variants simply reflect the balance between selection, mutation, and drift.
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Affiliation(s)
- Baptiste Saudemont
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, Inserm, Ecole Normale Supérieure, PSL Research University, F-75005 Paris, France
- (Epi)genomics of Animal Development Unit, Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France
| | - Alexandra Popa
- Université de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69100 Villeurbanne, France
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14 AKH BT25.3, 1090 Vienna, Austria
| | - Joanna L. Parmley
- Université de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69100 Villeurbanne, France
- General Bioinformatics, Reading Enterprise Centre, The University of Reading, Whiteknights Road, Reading, RG6 6BU UK
| | - Vincent Rocher
- Université de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69100 Villeurbanne, France
| | - Corinne Blugeon
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, Inserm, Ecole Normale Supérieure, PSL Research University, F-75005 Paris, France
| | - Anamaria Necsulea
- Université de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69100 Villeurbanne, France
| | - Eric Meyer
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, Inserm, Ecole Normale Supérieure, PSL Research University, F-75005 Paris, France
| | - Laurent Duret
- Université de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69100 Villeurbanne, France
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218
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Kim SW, Taggart AJ, Heintzelman C, Cygan KJ, Hull CG, Wang J, Shrestha B, Fairbrother WG. Widespread intra-dependencies in the removal of introns from human transcripts. Nucleic Acids Res 2017; 45:9503-9513. [PMID: 28934498 PMCID: PMC5766209 DOI: 10.1093/nar/gkx661] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 07/24/2017] [Indexed: 01/19/2023] Open
Abstract
Research into the problem of splice site selection has followed a reductionist approach focused on how individual splice sites are recognized. Early applications of information theory uncovered an inconsistency. Human splice signals do not contain enough information to explain the observed fidelity of splicing. Here, we conclude that introns do not necessarily contain ‘missing’ information but rather may require definition from neighboring processing events. For example, there are known cases where an intronic mutation disrupts the splicing of not only the local intron but also adjacent introns. We present a genome-wide measurement of the order of splicing within human transcripts. The observed order of splicing cannot be explained by a simple kinetic model. Simulations reveal a bias toward a particular, transcript-specific order of intron removal in human genes. We validate an extreme class of intron that can only splice in a multi-intron context. Special categories of splicing such as exon circularization, first and last intron processing, alternative 5 and 3′ss usage and exon skipping are marked by distinct patterns of ordered intron removal. Excessive intronic length and silencer density tend to delay splicing. Shorter introns that contain enhancers splice early.
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Affiliation(s)
- Seong Won Kim
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Allison J Taggart
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Claire Heintzelman
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Kamil J Cygan
- Center for Computational Molecular Biology, Brown University, Providence, RI 02903, USA
| | - Caitlin G Hull
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Jing Wang
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Barsha Shrestha
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - William G Fairbrother
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA.,Center for Computational Molecular Biology, Brown University, Providence, RI 02903, USA
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219
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Braun CJ, Stanciu M, Boutz PL, Patterson JC, Calligaris D, Higuchi F, Neupane R, Fenoglio S, Cahill DP, Wakimoto H, Agar NYR, Yaffe MB, Sharp PA, Hemann MT, Lees JA. Coordinated Splicing of Regulatory Detained Introns within Oncogenic Transcripts Creates an Exploitable Vulnerability in Malignant Glioma. Cancer Cell 2017; 32:411-426.e11. [PMID: 28966034 PMCID: PMC5929990 DOI: 10.1016/j.ccell.2017.08.018] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 06/05/2017] [Accepted: 08/30/2017] [Indexed: 01/22/2023]
Abstract
Glioblastoma (GBM) is a devastating malignancy with few therapeutic options. We identify PRMT5 in an in vivo GBM shRNA screen and show that PRMT5 knockdown or inhibition potently suppresses in vivo GBM tumors, including patient-derived xenografts. Pathway analysis implicates splicing in cellular PRMT5 dependency, and we identify a biomarker that predicts sensitivity to PRMT5 inhibition. We find that PRMT5 deficiency primarily disrupts the removal of detained introns (DIs). This impaired DI splicing affects proliferation genes, whose downregulation coincides with cell cycle defects, senescence and/or apoptosis. We further show that DI programs are evolutionarily conserved and operate during neurogenesis, suggesting that they represent a physiological regulatory mechanism. Collectively, these findings reveal a PRMT5-regulated DI-splicing program as an exploitable cancer vulnerability.
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Affiliation(s)
- Christian J Braun
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Monica Stanciu
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Paul L Boutz
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Jesse C Patterson
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - David Calligaris
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Fumi Higuchi
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Rachit Neupane
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Silvia Fenoglio
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Daniel P Cahill
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Hiroaki Wakimoto
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Nathalie Y R Agar
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA; Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - Michael B Yaffe
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Division of Acute Care Surgery, Trauma, and Critical Care, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Phillip A Sharp
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Michael T Hemann
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Jacqueline A Lees
- The David H. Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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220
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Abstract
Many mammalian genes contain poorly spliced introns, resulting in nuclear detention of partially spliced transcripts, which may be exploited to modulate gene expression. In this issue of Cancer Cell, Braun et al. report that the arginine methyltransferase PRMT5 is critical for tumor cell proliferation by regulating numerous detained introns.
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Affiliation(s)
- Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0651, USA.
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221
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Song X, Zeng Z, Wei H, Wang Z. Alternative splicing in cancers: From aberrant regulation to new therapeutics. Semin Cell Dev Biol 2017; 75:13-22. [PMID: 28919308 DOI: 10.1016/j.semcdb.2017.09.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 09/09/2017] [Accepted: 09/11/2017] [Indexed: 12/18/2022]
Abstract
Alternative splicing is one of the most common mechanisms for gene regulation in humans, and plays a vital role to increase the complexity of functional proteins. In this article, we seek to provide a general review on the relationships between alternative splicing and tumorigenesis. We briefly introduce the basic rules for regulation of alternative splicing, and discuss recent advances on dynamic regulation of alternative splicing in cancers by highlighting the roles of a variety of RNA splicing factors in tumorigenesis. We further discuss several important questions regarding the splicing of long noncoding RNAs and back-splicing of circular RNAs in cancers. Finally, we discuss the current technologies that can be used to manipulate alternative splicing and serve as potential cancer treatment.
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Affiliation(s)
- Xiaowei Song
- CAS Key Lab for Computational Biology, CAS Center for Excellence in Molecular Cell Science, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Department of Cardiology, Changhai Hospital, 168 Changhai Road, Shanghai 200433, China.
| | - Zhenyu Zeng
- Department of Cardiology, Changhai Hospital, 168 Changhai Road, Shanghai 200433, China
| | - Huanhuan Wei
- CAS Key Lab for Computational Biology, CAS Center for Excellence in Molecular Cell Science, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zefeng Wang
- CAS Key Lab for Computational Biology, CAS Center for Excellence in Molecular Cell Science, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
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222
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Tapial J, Ha KCH, Sterne-Weiler T, Gohr A, Braunschweig U, Hermoso-Pulido A, Quesnel-Vallières M, Permanyer J, Sodaei R, Marquez Y, Cozzuto L, Wang X, Gómez-Velázquez M, Rayon T, Manzanares M, Ponomarenko J, Blencowe BJ, Irimia M. An atlas of alternative splicing profiles and functional associations reveals new regulatory programs and genes that simultaneously express multiple major isoforms. Genome Res 2017; 27:1759-1768. [PMID: 28855263 PMCID: PMC5630039 DOI: 10.1101/gr.220962.117] [Citation(s) in RCA: 231] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 08/09/2017] [Indexed: 12/29/2022]
Abstract
Alternative splicing (AS) generates remarkable regulatory and proteomic complexity in metazoans. However, the functions of most AS events are not known, and programs of regulated splicing remain to be identified. To address these challenges, we describe the Vertebrate Alternative Splicing and Transcription Database (VastDB), the largest resource of genome-wide, quantitative profiles of AS events assembled to date. VastDB provides readily accessible quantitative information on the inclusion levels and functional associations of AS events detected in RNA-seq data from diverse vertebrate cell and tissue types, as well as developmental stages. The VastDB profiles reveal extensive new intergenic and intragenic regulatory relationships among different classes of AS and previously unknown and conserved landscapes of tissue-regulated exons. Contrary to recent reports concluding that nearly all human genes express a single major isoform, VastDB provides evidence that at least 48% of multiexonic protein-coding genes express multiple splice variants that are highly regulated in a cell/tissue-specific manner, and that >18% of genes simultaneously express multiple major isoforms across diverse cell and tissue types. Isoforms encoded by the latter set of genes are generally coexpressed in the same cells and are often engaged by translating ribosomes. Moreover, they are encoded by genes that are significantly enriched in functions associated with transcriptional control, implying they may have an important and wide-ranging role in controlling cellular activities. VastDB thus provides an unprecedented resource for investigations of AS function and regulation.
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Affiliation(s)
- Javier Tapial
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Kevin C H Ha
- Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | | | - André Gohr
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | | | - Antonio Hermoso-Pulido
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Mathieu Quesnel-Vallières
- Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Jon Permanyer
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Reza Sodaei
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Yamile Marquez
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Luca Cozzuto
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Xinchen Wang
- Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Melisa Gómez-Velázquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Teresa Rayon
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Miguel Manzanares
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Julia Ponomarenko
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | | | - Manuel Irimia
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
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223
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The RNA helicase DDX46 inhibits innate immunity by entrapping m 6A-demethylated antiviral transcripts in the nucleus. Nat Immunol 2017; 18:1094-1103. [PMID: 28846086 DOI: 10.1038/ni.3830] [Citation(s) in RCA: 246] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 08/07/2017] [Indexed: 12/15/2022]
Abstract
DEAD-box (DDX) helicases are vital for the recognition of RNA and metabolism and are critical for the initiation of antiviral innate immunity. Modification of RNA is involved in many biological processes; however, its role in antiviral innate immunity has remained unclear. Here we found that nuclear DDX member DDX46 inhibited the production of type I interferons after viral infection. DDX46 bound Mavs, Traf3 and Traf6 transcripts (which encode signaling molecules involved in antiviral responses) via their conserved CCGGUU element. After viral infection, DDX46 recruited ALKBH5, an 'eraser' of the RNA modification N6-methyladenosine (m6A), via DDX46's DEAD helicase domain to demethylate those m6A-modified antiviral transcripts. It consequently enforced their retention in the nucleus and therefore prevented their translation and inhibited interferon production. DDX46 also suppressed antiviral innate immunity in vivo. Thus, DDX46 inhibits antiviral innate responses by entrapping selected antiviral transcripts in the nucleus by erasing their m6A modification, a modification normally required for export from the nucleus and translation.
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224
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Pirnie SP, Osman A, Zhu Y, Carmichael GG. An Ultraconserved Element (UCE) controls homeostatic splicing of ARGLU1 mRNA. Nucleic Acids Res 2017; 45:3473-3486. [PMID: 27899669 PMCID: PMC5389617 DOI: 10.1093/nar/gkw1140] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 10/31/2016] [Indexed: 11/13/2022] Open
Abstract
Arginine and Glutamate-Rich protein 1 (ARGLU1) is a protein whose function is poorly understood, but may act in both transcription and pre-mRNA splicing. We demonstrate that the ARGLU1 gene expresses at least three distinct RNA splice isoforms – a fully spliced isoform coding for the protein, an isoform containing a retained intron that is detained in the nucleus, and an isoform containing an alternative exon that targets the transcript for nonsense mediated decay. Furthermore, ARGLU1 contains a long, highly evolutionarily conserved sequence known as an Ultraconserved Element (UCE) that is within the retained intron and overlaps the alternative exon. Manipulation of the UCE, in a reporter minigene or via random mutations in the genomic context using CRISPR/Cas9, changed the splicing pattern. Further, overexpression of the ARGLU1 protein shifted the splicing of endogenous ARGLU1 mRNA, resulting in an increase in the retained intron isoform and nonsense mediated decay susceptible isoform and a decrease in the fully spliced isoform. Taken together with data showing that functional protein knockout shifts splicing toward the fully spliced isoform, our data are consistent with a model in which unproductive splicing complexes assembled at the alternative exon lead to inefficient splicing and intron retention.
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Affiliation(s)
- Stephan P Pirnie
- Department of Genetics and Genome Sciences, UCONN Health Center, 400 Farmington Avenue, Farmington, CT 06030, USA
| | - Ahmad Osman
- Department of Genetics and Genome Sciences, UCONN Health Center, 400 Farmington Avenue, Farmington, CT 06030, USA
| | - Yinzhou Zhu
- Department of Genetics and Genome Sciences, UCONN Health Center, 400 Farmington Avenue, Farmington, CT 06030, USA
| | - Gordon G Carmichael
- Department of Genetics and Genome Sciences, UCONN Health Center, 400 Farmington Avenue, Farmington, CT 06030, USA
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225
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Lei L, Yan SY, Yang R, Chen JY, Li Y, Bu Y, Chang N, Zhou Q, Zhu X, Li CY, Xiong JW. Spliceosomal protein eftud2 mutation leads to p53-dependent apoptosis in zebrafish neural progenitors. Nucleic Acids Res 2017; 45:3422-3436. [PMID: 27899647 PMCID: PMC5389467 DOI: 10.1093/nar/gkw1043] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/24/2016] [Indexed: 12/26/2022] Open
Abstract
Haploinsufficiency of EFTUD2 (Elongation Factor Tu GTP Binding Domain Containing 2) is linked to human mandibulofacial dysostosis, Guion-Almeida type (MFDGA), but the underlying cellular and molecular mechanisms remain to be addressed. We report here the isolation, cloning and functional analysis of the mutated eftud2 (snu114) in a novel neuronal mutant fn10a in zebrafish. This mutant displayed abnormal brain development with evident neuronal apoptosis while the development of other organs appeared less affected. Positional cloning revealed a nonsense mutation such that the mutant eftud2 mRNA encoded a truncated Eftud2 protein and was subjected to nonsense-mediated decay. Disruption of eftud2 led to increased apoptosis and mitosis of neural progenitors while it had little effect on differentiated neurons. Further RNA-seq and functional analyses revealed a transcriptome-wide RNA splicing deficiency and a large amount of intron-retaining and exon-skipping transcripts, which resulted in inadequate nonsense-mediated RNA decay and activation of the p53 pathway in fn10a mutants. Therefore, our study has established that eftud2 functions in RNA splicing during neural development and provides a suitable zebrafish model for studying the molecular pathology of the neurological disease MFDGA.
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Affiliation(s)
- Lei Lei
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Shou-Yu Yan
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Ran Yang
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Jia-Yu Chen
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Yumei Li
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Ye Bu
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Nannan Chang
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Qinchao Zhou
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Xiaojun Zhu
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Chuan-Yun Li
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Jing-Wei Xiong
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
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226
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Milek M, Imami K, Mukherjee N, Bortoli FD, Zinnall U, Hazapis O, Trahan C, Oeffinger M, Heyd F, Ohler U, Selbach M, Landthaler M. DDX54 regulates transcriptome dynamics during DNA damage response. Genome Res 2017; 27:1344-1359. [PMID: 28596291 PMCID: PMC5538551 DOI: 10.1101/gr.218438.116] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 06/05/2017] [Indexed: 12/12/2022]
Abstract
The cellular response to genotoxic stress is mediated by a well-characterized network of DNA surveillance pathways. The contribution of post-transcriptional gene regulatory networks to the DNA damage response (DDR) has not been extensively studied. Here, we systematically identified RNA-binding proteins differentially interacting with polyadenylated transcripts upon exposure of human breast carcinoma cells to ionizing radiation (IR). Interestingly, more than 260 proteins, including many nucleolar proteins, showed increased binding to poly(A)+ RNA in IR-exposed cells. The functional analysis of DDX54, a candidate genotoxic stress responsive RNA helicase, revealed that this protein is an immediate-to-early DDR regulator required for the splicing efficacy of its target IR-induced pre-mRNAs. Upon IR exposure, DDX54 acts by increased interaction with a well-defined class of pre-mRNAs that harbor introns with weak acceptor splice sites, as well as by protein-protein contacts within components of U2 snRNP and spliceosomal B complex, resulting in lower intron retention and higher processing rates of its target transcripts. Because DDX54 promotes survival after exposure to IR, its expression and/or mutation rate may impact DDR-related pathologies. Our work indicates the relevance of many uncharacterized RBPs potentially involved in the DDR.
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Affiliation(s)
- Miha Milek
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Koshi Imami
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Neelanjan Mukherjee
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Francesca De Bortoli
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Ulrike Zinnall
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Orsalia Hazapis
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Christian Trahan
- Institut de Recherches Cliniques de Montréal, H2W 1R7 Montréal, Quebec, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, H3A 1A3 Montréal, Quebec, Canada
| | - Marlene Oeffinger
- Institut de Recherches Cliniques de Montréal, H2W 1R7 Montréal, Quebec, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, H3A 1A3 Montréal, Quebec, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, H3T 1J4 Montréal, Quebec, Canada
| | - Florian Heyd
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Uwe Ohler
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Department of Computer Science, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Matthias Selbach
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- Charite-Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Markus Landthaler
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- IRI Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
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227
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Mauger O, Lemoine F, Scheiffele P. Targeted Intron Retention and Excision for Rapid Gene Regulation in Response to Neuronal Activity. Neuron 2017; 92:1266-1278. [PMID: 28009274 DOI: 10.1016/j.neuron.2016.11.032] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 10/14/2016] [Accepted: 11/18/2016] [Indexed: 01/03/2023]
Abstract
Activity-dependent transcription has emerged as a major source of gene products that regulate neuronal excitability, connectivity, and synaptic properties. However, the elongation rate of RNA polymerases imposes a significant temporal constraint for transcript synthesis, in particular for long genes where new synthesis requires hours. Here we reveal a novel, transcription-independent mechanism that releases transcripts within minutes of neuronal stimulation. We found that, in the mouse neocortex, polyadenylated transcripts retain select introns and are stably accumulated in the cell nucleus. A subset of these intron retention transcripts undergoes activity-dependent splicing, cytoplasmic export, and ribosome loading, thus acutely releasing mRNAs in response to stimulation. This process requires NMDA receptor- and calmodulin-dependent kinase pathways, and it is particularly prevalent for long transcripts. We conclude that regulated intron retention in fully transcribed RNAs represents a mechanism to rapidly mobilize a pool of mRNAs in response to neuronal activity.
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Affiliation(s)
- Oriane Mauger
- Biozentrum of the University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland
| | - Frédéric Lemoine
- GenoSplice Technology, iPEPS-ICM, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Peter Scheiffele
- Biozentrum of the University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland.
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228
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Komor MA, Pham TV, Hiemstra AC, Piersma SR, Bolijn AS, Schelfhorst T, Delis-van Diemen PM, Tijssen M, Sebra RP, Ashby M, Meijer GA, Jimenez CR, Fijneman RJA. Identification of Differentially Expressed Splice Variants by the Proteogenomic Pipeline Splicify. Mol Cell Proteomics 2017; 16:1850-1863. [PMID: 28747380 DOI: 10.1074/mcp.tir117.000056] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Indexed: 12/20/2022] Open
Abstract
Proteogenomics, i.e. comprehensive integration of genomics and proteomics data, is a powerful approach identifying novel protein biomarkers. This is especially the case for proteins that differ structurally between disease and control conditions. As tumor development is associated with aberrant splicing, we focus on this rich source of cancer specific biomarkers. To this end, we developed a proteogenomic pipeline, Splicify, which can detect differentially expressed protein isoforms. Splicify is based on integrating RNA massive parallel sequencing data and tandem mass spectrometry proteomics data to identify protein isoforms resulting from differential splicing between two conditions. Proof of concept was obtained by applying Splicify to RNA sequencing and mass spectrometry data obtained from colorectal cancer cell line SW480, before and after siRNA-mediated downmodulation of the splicing factors SF3B1 and SRSF1. These analyses revealed 2172 and 149 differentially expressed isoforms, respectively, with peptide confirmation upon knock-down of SF3B1 and SRSF1 compared with their controls. Splice variants identified included RAC1, OSBPL3, MKI67, and SYK. One additional sample was analyzed by PacBio Iso-Seq full-length transcript sequencing after SF3B1 downmodulation. This analysis verified the alternative splicing identified by Splicify and in addition identified novel splicing events that were not represented in the human reference genome annotation. Therefore, Splicify offers a validated proteogenomic data analysis pipeline for identification of disease specific protein biomarkers resulting from mRNA alternative splicing. Splicify is publicly available on GitHub (https://github.com/NKI-TGO/SPLICIFY) and suitable to address basic research questions using pre-clinical model systems as well as translational research questions using patient-derived samples, e.g. allowing to identify clinically relevant biomarkers.
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Affiliation(s)
- Malgorzata A Komor
- From the ‡Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands.,§Oncoproteomics Laboratory, Department of Medical Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | - Thang V Pham
- §Oncoproteomics Laboratory, Department of Medical Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | - Annemieke C Hiemstra
- From the ‡Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Sander R Piersma
- §Oncoproteomics Laboratory, Department of Medical Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | - Anne S Bolijn
- From the ‡Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Tim Schelfhorst
- §Oncoproteomics Laboratory, Department of Medical Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | - Pien M Delis-van Diemen
- From the ‡Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Marianne Tijssen
- From the ‡Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Robert P Sebra
- ¶School of Medicine at Mount Sinai, Institute for Genomics and Multiscale Biology, New York, New York
| | | | - Gerrit A Meijer
- From the ‡Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Connie R Jimenez
- §Oncoproteomics Laboratory, Department of Medical Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | - Remond J A Fijneman
- From the ‡Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands;
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229
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Pendleton KE, Chen B, Liu K, Hunter OV, Xie Y, Tu BP, Conrad NK. The U6 snRNA m 6A Methyltransferase METTL16 Regulates SAM Synthetase Intron Retention. Cell 2017; 169:824-835.e14. [PMID: 28525753 DOI: 10.1016/j.cell.2017.05.003] [Citation(s) in RCA: 691] [Impact Index Per Article: 98.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/16/2017] [Accepted: 04/28/2017] [Indexed: 12/15/2022]
Abstract
Maintenance of proper levels of the methyl donor S-adenosylmethionine (SAM) is critical for a wide variety of biological processes. We demonstrate that the N6-adenosine methyltransferase METTL16 regulates expression of human MAT2A, which encodes the SAM synthetase expressed in most cells. Upon SAM depletion by methionine starvation, cells induce MAT2A expression by enhanced splicing of a retained intron. Induction requires METTL16 and its methylation substrate, a vertebrate conserved hairpin (hp1) in the MAT2A 3' UTR. Increasing METTL16 occupancy on the MAT2A 3' UTR is sufficient to induce efficient splicing. We propose that, under SAM-limiting conditions, METTL16 occupancy on hp1 increases due to inefficient enzymatic turnover, which promotes MAT2A splicing. We further show that METTL16 is the long-unknown methyltransferase for the U6 spliceosomal small nuclear RNA (snRNA). These observations suggest that the conserved U6 snRNA methyltransferase evolved an additional function in vertebrates to regulate SAM homeostasis.
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Affiliation(s)
- Kathryn E Pendleton
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Beibei Chen
- Department of Clinical Sciences, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kuanqing Liu
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Olga V Hunter
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yang Xie
- Department of Clinical Sciences, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Benjamin P Tu
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Nicholas K Conrad
- Department of Microbiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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230
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Regulated Intron Removal Integrates Motivational State and Experience. Cell 2017; 169:836-848.e15. [PMID: 28525754 DOI: 10.1016/j.cell.2017.05.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/23/2017] [Accepted: 05/01/2017] [Indexed: 11/23/2022]
Abstract
Myriad experiences produce transient memory, yet, contingent on the internal state of the organism and the saliency of the experience, only some memories persist over time. How experience and internal state influence the duration of memory at the molecular level remains unknown. A self-assembled aggregated state of Drosophila Orb2A protein is required specifically for long-lasting memory. We report that in the adult fly brain the mRNA encoding Orb2A protein exists in an unspliced non-protein-coding form. The convergence of experience and internal drive transiently increases the spliced protein-coding Orb2A mRNA. A screen identified pasilla, the fly ortholog of mammalian Nova-1/2, as a mediator of Orb2A mRNA processing. A single-nucleotide substitution in the intronic region that reduces Pasilla binding and intron removal selectively impairs long-term memory. We posit that pasilla-mediated processing of unspliced Orb2A mRNA integrates experience and internal state to control Orb2A protein abundance and long-term memory formation.
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231
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Evrony GD, Cordero DR, Shen J, Partlow JN, Yu TW, Rodin RE, Hill RS, Coulter ME, Lam ATN, Jayaraman D, Gerrelli D, Diaz DG, Santos C, Morrison V, Galli A, Tschulena U, Wiemann S, Martel MJ, Spooner B, Ryu SC, Elhosary PC, Richardson JM, Tierney D, Robinson CA, Chibbar R, Diudea D, Folkerth R, Wiebe S, Barkovich AJ, Mochida GH, Irvine J, Lemire EG, Blakley P, Walsh CA. Integrated genome and transcriptome sequencing identifies a noncoding mutation in the genome replication factor DONSON as the cause of microcephaly-micromelia syndrome. Genome Res 2017. [PMID: 28630177 PMCID: PMC5538549 DOI: 10.1101/gr.219899.116] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
While next-generation sequencing has accelerated the discovery of human disease genes, progress has been largely limited to the “low hanging fruit” of mutations with obvious exonic coding or canonical splice site impact. In contrast, the lack of high-throughput, unbiased approaches for functional assessment of most noncoding variants has bottlenecked gene discovery. We report the integration of transcriptome sequencing (RNA-seq), which surveys all mRNAs to reveal functional impacts of variants at the transcription level, into the gene discovery framework for a unique human disease, microcephaly-micromelia syndrome (MMS). MMS is an autosomal recessive condition described thus far in only a single First Nations population and causes intrauterine growth restriction, severe microcephaly, craniofacial anomalies, skeletal dysplasia, and neonatal lethality. Linkage analysis of affected families, including a very large pedigree, identified a single locus on Chromosome 21 linked to the disease (LOD > 9). Comprehensive genome sequencing did not reveal any pathogenic coding or canonical splicing mutations within the linkage region but identified several nonconserved noncoding variants. RNA-seq analysis detected aberrant splicing in DONSON due to one of these noncoding variants, showing a causative role for DONSON disruption in MMS. We show that DONSON is expressed in progenitor cells of embryonic human brain and other proliferating tissues, is co-expressed with components of the DNA replication machinery, and that Donson is essential for early embryonic development in mice as well, suggesting an essential conserved role for DONSON in the cell cycle. Our results demonstrate the utility of integrating transcriptomics into the study of human genetic disease when DNA sequencing alone is not sufficient to reveal the underlying pathogenic mutation.
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Affiliation(s)
- Gilad D Evrony
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Dwight R Cordero
- Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jun Shen
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.,Laboratory of Molecular Medicine, Partners Personalized Medicine, Cambridge, Massachusetts 02139, USA
| | - Jennifer N Partlow
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Timothy W Yu
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Rachel E Rodin
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - R Sean Hill
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Michael E Coulter
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Anh-Thu N Lam
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Divya Jayaraman
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Dianne Gerrelli
- Institute of Child Health, University College London, London WC1N 1EH, United Kingdom
| | - Diana G Diaz
- Institute of Child Health, University College London, London WC1N 1EH, United Kingdom
| | - Chloe Santos
- Institute of Child Health, University College London, London WC1N 1EH, United Kingdom
| | - Victoria Morrison
- Institute of Child Health, University College London, London WC1N 1EH, United Kingdom
| | - Antonella Galli
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Ulrich Tschulena
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Stefan Wiemann
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - M Jocelyne Martel
- Department of Obstetrics and Gynecology, University of Saskatchewan College of Medicine, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Betty Spooner
- Northern Medical Services, University of Saskatchewan College of Medicine, Saskatoon, Saskatchewan S7K 0L4, Canada
| | - Steven C Ryu
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Princess C Elhosary
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Jillian M Richardson
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Danielle Tierney
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Christopher A Robinson
- Department of Pathology, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Rajni Chibbar
- Department of Pathology, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Dana Diudea
- Department of Pathology, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Rebecca Folkerth
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Sheldon Wiebe
- Department of Medical Imaging, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - A James Barkovich
- Department of Radiology, University of California San Francisco, San Francisco, California 94143, USA
| | - Ganeshwaran H Mochida
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - James Irvine
- Northern Medical Services, University of Saskatchewan College of Medicine, Saskatoon, Saskatchewan S7K 0L4, Canada.,Population Health Unit, Mamawetan Churchill River and Keewatin-Yatthé Health Regions, and Athabasca Health Authority, La Ronge, Saskatchewan S0J 1L0, Canada
| | - Edmond G Lemire
- Department of Pediatrics, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Patricia Blakley
- Department of Pediatrics, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Neurology and Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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232
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Beyond proteome diversity: alternative splicing as a regulator of neuronal transcript dynamics. Curr Opin Neurobiol 2017; 45:162-168. [PMID: 28609697 DOI: 10.1016/j.conb.2017.05.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/07/2017] [Accepted: 05/14/2017] [Indexed: 12/21/2022]
Abstract
Brain development and function are governed by tightly controlled gene expression programs. Transcriptional repertoires in neurons are highly specific to developmental stage, neuronal cell type and can undergo rapid changes upon neuronal stimulation. Dedicated molecular mechanisms are required to achieve such fine-tuned regulation. In addition to transcriptional programs, post-transcriptional processes and notably alternative splicing substantially contribute to the elaboration of neuronal gene expression. While alternative splicing has been viewed primarily as a means for expanding proteome diversity, it emerges to also be a major regulator of transcript levels and dynamics. In this review we will describe some of the principal alternative splicing-linked mechanisms that control neuronal transcriptomes and discuss their implications for the central nervous system.
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233
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Deveson IW, Holleley CE, Blackburn J, Marshall Graves JA, Mattick JS, Waters PD, Georges A. Differential intron retention in Jumonji chromatin modifier genes is implicated in reptile temperature-dependent sex determination. SCIENCE ADVANCES 2017; 3:e1700731. [PMID: 28630932 PMCID: PMC5470834 DOI: 10.1126/sciadv.1700731] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In many vertebrates, sex of offspring is determined by external environmental cues rather than by sex chromosomes. In reptiles, for instance, temperature-dependent sex determination (TSD) is common. Despite decades of work, the mechanism by which temperature is converted into a sex-determining signal remains mysterious. This is partly because it is difficult to distinguish the primary molecular events of TSD from the confounding downstream signatures of sexual differentiation. We use the Australian central bearded dragon, in which chromosomal sex determination is overridden at high temperatures to produce sex-reversed female offspring, as a unique model to identify TSD-specific features of the transcriptome. We show that an intron is retained in mature transcripts from each of two Jumonji family genes, JARID2 and JMJD3, in female dragons that have been sex-reversed by temperature but not in normal chromosomal females or males. JARID2 is a component of the master chromatin modifier Polycomb Repressive Complex 2, and the mammalian sex-determining factor SRY is directly regulated by an independent but closely related Jumonji family member. We propose that the perturbation of JARID2/JMJD3 function by intron retention alters the epigenetic landscape to override chromosomal sex-determining cues, triggering sex reversal at extreme temperatures. Sex reversal may then facilitate a transition from genetic sex determination to TSD, with JARID2/JMJD3 intron retention preserved as the decisive regulatory signal. Significantly, we also observe sex-associated differential retention of the equivalent introns in JARID2/JMJD3 transcripts expressed in embryonic gonads from TSD alligators and turtles, indicative of a reptile-wide mechanism controlling TSD.
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Affiliation(s)
- Ira W. Deveson
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Clare E. Holleley
- Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory, Australia
- Australian National Wildlife Collection, National Research Collections Australia, CSIRO, Canberra, Australian Capital Territory, Australia
| | - James Blackburn
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St. Vincent’s Clinical School, UNSW, Sydney, New South Wales, Australia
| | - Jennifer A. Marshall Graves
- Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory, Australia
- School of Life Sciences, La Trobe University, Bundoora, Victoria, Australia
| | - John S. Mattick
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
- St. Vincent’s Clinical School, UNSW, Sydney, New South Wales, Australia
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Paul D. Waters
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory, Australia
- Corresponding author.
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234
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Steward CA, Parker APJ, Minassian BA, Sisodiya SM, Frankish A, Harrow J. Genome annotation for clinical genomic diagnostics: strengths and weaknesses. Genome Med 2017; 9:49. [PMID: 28558813 PMCID: PMC5448149 DOI: 10.1186/s13073-017-0441-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The Human Genome Project and advances in DNA sequencing technologies have revolutionized the identification of genetic disorders through the use of clinical exome sequencing. However, in a considerable number of patients, the genetic basis remains unclear. As clinicians begin to consider whole-genome sequencing, an understanding of the processes and tools involved and the factors to consider in the annotation of the structure and function of genomic elements that might influence variant identification is crucial. Here, we discuss and illustrate the strengths and weaknesses of approaches for the annotation and classification of important elements of protein-coding genes, other genomic elements such as pseudogenes and the non-coding genome, comparative-genomic approaches for inferring gene function, and new technologies for aiding genome annotation, as a practical guide for clinicians when considering pathogenic sequence variation. Complete and accurate annotation of structure and function of genome features has the potential to reduce both false-negative (from missing annotation) and false-positive (from incorrect annotation) errors in causal variant identification in exome and genome sequences. Re-analysis of unsolved cases will be necessary as newer technology improves genome annotation, potentially improving the rate of diagnosis.
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Affiliation(s)
- Charles A Steward
- Congenica Ltd, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1DR, UK. .,The Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
| | | | - Berge A Minassian
- Department of Pediatrics (Neurology), University of Texas Southwestern, Dallas, TX, USA.,Program in Genetics and Genome Biology and Department of Paediatrics (Neurology), The Hospital for Sick Children and University of Toronto, Toronto, Canada
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, WC1N 3BG, UK.,Chalfont Centre for Epilepsy, Chesham Lane, Chalfont St Peter, Buckinghamshire, SL9 0RJ, UK
| | - Adam Frankish
- The Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.,European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Jennifer Harrow
- The Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.,Illumina Inc, Great Chesterford, Essex, CB10 1XL, UK
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235
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Verbeeren J, Verma B, Niemelä EH, Yap K, Makeyev EV, Frilander MJ. Alternative exon definition events control the choice between nuclear retention and cytoplasmic export of U11/U12-65K mRNA. PLoS Genet 2017; 13:e1006824. [PMID: 28549066 PMCID: PMC5473595 DOI: 10.1371/journal.pgen.1006824] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 06/16/2017] [Accepted: 05/16/2017] [Indexed: 12/20/2022] Open
Abstract
Cellular homeostasis of the minor spliceosome is regulated by a negative feed-back loop that targets U11-48K and U11/U12-65K mRNAs encoding essential components of the U12-type intron-specific U11/U12 di-snRNP. This involves interaction of the U11 snRNP with an evolutionarily conserved splicing enhancer giving rise to unproductive mRNA isoforms. In the case of U11/U12-65K, this mechanism controls the length of the 3′ untranslated region (3′UTR). We show that this process is dynamically regulated in developing neurons and some other cell types, and involves a binary switch between translation-competent mRNAs with a short 3′UTR to non-productive isoforms with a long 3′UTR that are retained in the nucleus or/and spliced to the downstream amylase locus. Importantly, the choice between these alternatives is determined by alternative terminal exon definition events regulated by conserved U12- and U2-type 5′ splice sites as well as sequence signals used for pre-mRNA cleavage and polyadenylation. We additionally show that U11 snRNP binding to the U11/U12-65K mRNA species with a long 3′UTR is required for their nuclear retention. Together, our studies uncover an intricate molecular circuitry regulating the abundance of a key spliceosomal protein and shed new light on the mechanisms limiting the export of non-productively spliced mRNAs from the nucleus to the cytoplasm. The cellular homeostasis of many components of the eukaryotic RNA processing machinery is regulated via negative feed-back pathways that result in the formation of both productive and non-productive mRNA species. Typically, the formation of non-productive mRNAs species results from changes in alternative splicing that disrupt the reading frame of the protein coding region and leads to destabilization of the mRNA. Here, we have investigated the homeostasis regulation of the U11/U12-65K mRNA that encodes an essential protein component of the minor (U12-dependent) spliceosome intron recognition complex. We show that homeostasis is regulated at the level of nuclear mRNA export and mRNA 3′-end formation, and that it can be further regulated during neuronal differentiation. We describe a multilayered regulatory system utilizing alternative exon definition interactions that use the input from both spliceosomes and the polyadenylation machinery to decide between productive and non-productive mRNA formation. Because the 65K protein is an essential component of the minor spliceosome, this regulatory pathway can potentially affect the expression of ~700 genes containing U12-type introns.
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Affiliation(s)
- Jens Verbeeren
- Institute of Biotechnology, FI-00014 University of Helsinki, Helsinki, Finland
| | - Bhupendra Verma
- Institute of Biotechnology, FI-00014 University of Helsinki, Helsinki, Finland
| | - Elina H. Niemelä
- Institute of Biotechnology, FI-00014 University of Helsinki, Helsinki, Finland
| | - Karen Yap
- Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
| | - Eugene V. Makeyev
- Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
| | - Mikko J. Frilander
- Institute of Biotechnology, FI-00014 University of Helsinki, Helsinki, Finland
- * E-mail:
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236
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Deveson IW, Hardwick SA, Mercer TR, Mattick JS. The Dimensions, Dynamics, and Relevance of the Mammalian Noncoding Transcriptome. Trends Genet 2017; 33:464-478. [PMID: 28535931 DOI: 10.1016/j.tig.2017.04.004] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/24/2017] [Indexed: 01/02/2023]
Abstract
The combination of pervasive transcription and prolific alternative splicing produces a mammalian transcriptome of great breadth and diversity. The majority of transcribed genomic bases are intronic, antisense, or intergenic to protein-coding genes, yielding a plethora of short and long non-protein-coding regulatory RNAs. Long noncoding RNAs (lncRNAs) share most aspects of their biogenesis, processing, and regulation with mRNAs. However, lncRNAs are typically expressed in more restricted patterns, frequently from enhancers, and exhibit almost universal alternative splicing. These features are consistent with their role as modular epigenetic regulators. We describe here the key studies and technological advances that have shaped our understanding of the dimensions, dynamics, and biological relevance of the mammalian noncoding transcriptome.
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Affiliation(s)
- Ira W Deveson
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia; School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia
| | - Simon A Hardwick
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Tim R Mercer
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - John S Mattick
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia; School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia.
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237
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Deep intronic mutations and human disease. Hum Genet 2017; 136:1093-1111. [DOI: 10.1007/s00439-017-1809-4] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/05/2017] [Indexed: 12/22/2022]
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238
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Chakravorty S, Hegde M. Gene and Variant Annotation for Mendelian Disorders in the Era of Advanced Sequencing Technologies. Annu Rev Genomics Hum Genet 2017; 18:229-256. [PMID: 28415856 DOI: 10.1146/annurev-genom-083115-022545] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Comprehensive annotations of genetic and noncoding regions and corresponding accurate variant classification for Mendelian diseases are the next big challenge in the new genomic era of personalized medicine. Progress in the development of faster and more accurate pipelines for genome annotation and variant classification will lead to the discovery of more novel disease associations and candidate therapeutic targets. This ultimately will facilitate better patient recruitment in clinical trials. In this review, we describe the trends in research at the intersection of basic and clinical genomics that aims to increase understanding of overall genomic complexity, complex inheritance patterns of disease, and patient-phenotype-specific genomic associations. We describe the emerging field of translational functional genomics, which integrates other functional "-omics" approaches that support next-generation sequencing genomic data in order to facilitate personalized diagnostics, disease management, biomarker discovery, and medicine. We also discuss the utility of this integrated approach for diagnostic clinics and medical databases and its role in the future of personalized medicine.
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Affiliation(s)
- Samya Chakravorty
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322;
| | - Madhuri Hegde
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322;
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239
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Jacob AG, Smith CWJ. Intron retention as a component of regulated gene expression programs. Hum Genet 2017; 136:1043-1057. [PMID: 28391524 PMCID: PMC5602073 DOI: 10.1007/s00439-017-1791-x] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 03/29/2017] [Indexed: 12/16/2022]
Abstract
Intron retention has long been an exemplar of regulated splicing with case studies of individual events serving as models that provided key mechanistic insights into the process of splicing control. In organisms such as plants and budding yeast, intron retention is well understood as a major mechanism of gene expression regulation. In contrast, in mammalian systems, the extent and functional significance of intron retention have, until recently, remained greatly underappreciated. Technical challenges to the global detection and quantitation of transcripts with retained introns have often led to intron retention being overlooked or dismissed as “noise”. Now, however, with the wealth of information available from high-throughput deep sequencing, combined with focused computational and statistical analyses, we are able to distinguish clear intron retention patterns in various physiological and pathological contexts. Several recent studies have demonstrated intron retention as a central component of gene expression programs during normal development as well as in response to stress and disease. Furthermore, these studies revealed various ways in which intron retention regulates protein isoform production, RNA stability and translation efficiency, and rapid induction of expression via post-transcriptional splicing of retained introns. In this review, we highlight critical findings from these transcriptomic studies and discuss commonalties in the patterns prevalent in intron retention networks at the functional and regulatory levels.
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Affiliation(s)
- Aishwarya G Jacob
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Christopher W J Smith
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK.
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240
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Fernández-Moya SM, Ehses J, Kiebler MA. The alternative life of RNA-sequencing meets single molecule approaches. FEBS Lett 2017; 591:1455-1470. [PMID: 28369835 DOI: 10.1002/1873-3468.12639] [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: 02/22/2017] [Revised: 03/15/2017] [Accepted: 03/24/2017] [Indexed: 12/31/2022]
Abstract
The central dogma of RNA processing has started to totter. Single genes produce a variety of mRNA isoforms by mRNA modification, alternative polyadenylation (APA), and splicing. Different isoforms, even those that code for the identical protein, may differ in function or spatiotemporal expression. One option of how this can be achieved is by the selective recruitment of trans-acting factors to the 3'-untranslated region of a given isoform. Recent innovations in high-throughput RNA-sequencing methods allow deep insight into global RNA regulation, whereas novel imaging-based technologies enable researchers to explore single RNA molecules during different stages of development, in different tissues and different compartments of the cell. Resolving the dynamic function of ribonucleoprotein particles in splicing, APA, or RNA modification will enable us to understand their contribution to pathological conditions.
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Affiliation(s)
| | - Janina Ehses
- BioMedical Center, Ludwig Maximilians University, Planegg-Martinsried, Germany
| | - Michael A Kiebler
- BioMedical Center, Ludwig Maximilians University, Planegg-Martinsried, Germany
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241
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An Orchestrated Intron Retention Program in Meiosis Controls Timely Usage of Transcripts during Germ Cell Differentiation. Dev Cell 2017; 41:82-93.e4. [PMID: 28366282 PMCID: PMC5392497 DOI: 10.1016/j.devcel.2017.03.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/24/2017] [Accepted: 03/03/2017] [Indexed: 12/11/2022]
Abstract
Global transcriptome reprogramming during spermatogenesis ensures timely expression of factors in each phase of male germ cell differentiation. Spermatocytes and spermatids require particularly extensive reprogramming of gene expression to switch from mitosis to meiosis and to support gamete morphogenesis. Here, we uncovered an extensive alternative splicing program during this transmeiotic differentiation. Notably, intron retention was largely the most enriched pattern, with spermatocytes showing generally higher levels of retention compared with spermatids. Retained introns are characterized by weak splice sites and are enriched in genes with strong relevance for gamete function. Meiotic intron-retaining transcripts (IRTs) were exclusively localized in the nucleus. However, differently from other developmentally regulated IRTs, they are stable RNAs, showing longer half-life than properly spliced transcripts. Strikingly, fate-mapping experiments revealed that IRTs are recruited onto polyribosomes days after synthesis. These studies reveal an unexpected function for regulated intron retention in modulation of the timely expression of select transcripts during spermatogenesis.
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242
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Björk P, Wieslander L. Integration of mRNP formation and export. Cell Mol Life Sci 2017; 74:2875-2897. [PMID: 28314893 PMCID: PMC5501912 DOI: 10.1007/s00018-017-2503-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
Expression of protein-coding genes in eukaryotes relies on the coordinated action of many sophisticated molecular machineries. Transcription produces precursor mRNAs (pre-mRNAs) and the active gene provides an environment in which the pre-mRNAs are processed, folded, and assembled into RNA–protein (RNP) complexes. The dynamic pre-mRNPs incorporate the growing transcript, proteins, and the processing machineries, as well as the specific protein marks left after processing that are essential for export and the cytoplasmic fate of the mRNPs. After release from the gene, the mRNPs move by diffusion within the interchromatin compartment, making up pools of mRNPs. Here, splicing and polyadenylation can be completed and the mRNPs recruit the major export receptor NXF1. Export competent mRNPs interact with the nuclear pore complex, leading to export, concomitant with compositional and conformational changes of the mRNPs. We summarize the integrated nuclear processes involved in the formation and export of mRNPs.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Lars Wieslander
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
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243
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Middleton R, Gao D, Thomas A, Singh B, Au A, Wong JJL, Bomane A, Cosson B, Eyras E, Rasko JEJ, Ritchie W. IRFinder: assessing the impact of intron retention on mammalian gene expression. Genome Biol 2017; 18:51. [PMID: 28298237 PMCID: PMC5353968 DOI: 10.1186/s13059-017-1184-4] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/27/2017] [Indexed: 01/05/2023] Open
Abstract
Intron retention (IR) occurs when an intron is transcribed into pre-mRNA and remains in the final mRNA. We have developed a program and database called IRFinder to accurately detect IR from mRNA sequencing data. Analysis of 2573 samples showed that IR occurs in all tissues analyzed, affects over 80% of all coding genes and is associated with cell differentiation and the cell cycle. Frequently retained introns are enriched for specific RNA binding protein sites and are often retained in clusters in the same gene. IR is associated with lower protein levels and intron-retaining transcripts that escape nonsense-mediated decay are not actively translated.
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Affiliation(s)
- Robert Middleton
- Bioinformatics Laboratory, Centenary Institute, Camperdown, 2050, Australia
| | - Dadi Gao
- Bioinformatics Laboratory, Centenary Institute, Camperdown, 2050, Australia.,Molecular Neurogenetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA.,Boston & Harvard Medical School, Boston, MA, USA.,Gene & Stem Cell Therapy Program, Centenary Institute, Camperdown, 2050, Australia
| | | | - Babita Singh
- Pompeu Fabra University, UPF, Dr. Aiguader 88, E08003, Barcelona, Spain
| | - Amy Au
- Gene & Stem Cell Therapy Program, Centenary Institute, Camperdown, 2050, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, 2006, Australia
| | - Justin J-L Wong
- Gene & Stem Cell Therapy Program, Centenary Institute, Camperdown, 2050, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, 2006, Australia.,Gene Regulation in Cancer Laboratory, Centenary Institute, University of Sydney, Camperdown, 2050, Australia
| | - Alexandra Bomane
- Université Paris Diderot, Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR7216, CNRS, F-75013, Paris, France
| | - Bertrand Cosson
- Université Paris Diderot, Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR7216, CNRS, F-75013, Paris, France
| | - Eduardo Eyras
- Pompeu Fabra University, UPF, Dr. Aiguader 88, E08003, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies, ICREA, Passeig Lluís Companys 23, E08010, Barcelona, Spain
| | - John E J Rasko
- Gene & Stem Cell Therapy Program, Centenary Institute, Camperdown, 2050, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, 2006, Australia.,Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, 2050, Australia
| | - William Ritchie
- Bioinformatics Laboratory, Centenary Institute, Camperdown, 2050, Australia. .,CNRS, UPR 1142, Montpellier, 34094, France. .,CNRS, UMR 5203, Montpellier, 34094, France.
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244
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CLK-dependent exon recognition and conjoined gene formation revealed with a novel small molecule inhibitor. Nat Commun 2017; 8:7. [PMID: 28232751 PMCID: PMC5431906 DOI: 10.1038/s41467-016-0008-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/14/2016] [Indexed: 12/28/2022] Open
Abstract
CDC-like kinase phosphorylation of serine/arginine-rich proteins is central to RNA splicing reactions. Yet, the genomic network of CDC-like kinase-dependent RNA processing events remains poorly defined. Here, we explore the connectivity of genomic CDC-like kinase splicing functions by applying graduated, short-exposure, pharmacological CDC-like kinase inhibition using a novel small molecule (T3) with very high potency, selectivity, and cell-based stability. Using RNA-Seq, we define CDC-like kinase-responsive alternative splicing events, the large majority of which monotonically increase or decrease with increasing CDC-like kinase inhibition. We show that distinct RNA-binding motifs are associated with T3 response in skipped exons. Unexpectedly, we observe dose-dependent conjoined gene transcription, which is associated with motif enrichment in the last and second exons of upstream and downstream partners, respectively. siRNA knockdown of CLK2-associated genes significantly increases conjoined gene formation. Collectively, our results reveal an unexpected role for CDC-like kinase in conjoined gene formation, via regulation of 3′-end processing and associated splicing factors. The phosphorylation of serine/arginine-rich proteins by CDC-like kinase is a central regulatory mechanism for RNA splicing reactions. Here, the authors synthesize a novel small molecule CLK inhibitor and map CLK-responsive alternative splicing events and discover an effect on conjoined gene transcription.
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245
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Abstract
MDM4, an essential negative regulator of the P53 tumor suppressor, is frequently overexpressed in cancer cells that harbor a wild-type P53. By a mechanism based on alternative splicing, the MDM4 gene generates two mutually exclusive isoforms: MDM4-FL, which encodes the full-length MDM4 protein, and a shorter splice variant called MDM4-S. Previous results suggested that the MDM4-S isoform could be an important driver of tumor development. In this short review, we discuss a recent set of data indicating that MDM4-S is more likely a passenger isoform during tumorigenesis and that targeting MDM4 splicing to prevent MDM4-FL protein expression appears as a promising strategy to reactivate p53 in cancer cells. The benefits and risks associated with this strategy are also discussed.
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246
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Abstract
Fully grown oocytes arrest meiosis at prophase I and deposit maternal RNAs. A subset of maternal transcripts is stored in a dormant state in the oocyte, and the timely driven translation of specific mRNAs guides meiotic progression, the oocyte-embryo transition, and early embryo development. In the absence of transcription, the regulation of gene expression in oocytes is controlled almost exclusively at the level of transcriptome and proteome stabilization and at the level of protein synthesis.This chapter focuses on the recent findings on RNA distribution related to the temporal and spatial translational control of the meiotic cycle progression in mammalian oocytes. We discuss the most relevant mechanisms involved in the organization of the oocyte's maternal transcriptome storage and localization, and the regulation of translation, in correlation with the regulation of oocyte meiotic progression.
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247
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Abramczuk MK, Burkard TR, Rolland V, Steinmann V, Duchek P, Jiang Y, Wissel S, Reichert H, Knoblich JA. The splicing co-factor Barricade/Tat-SF1, is required for cell cycle and lineage progression in Drosophila neural stem cells. Development 2017; 144:3932-3945. [DOI: 10.1242/dev.152199] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 09/11/2017] [Indexed: 12/25/2022]
Abstract
Stem cells need to balance self-renewal and differentiation for correct tissue development and homeostasis. Defects in this balance can lead to developmental defects or tumor formation. In recent years, mRNA splicing has emerged as one important mechanism regulating cell fate decisions. Here we address the role of the evolutionary conserved splicing co-factor Barricade (Barc)/Tat-SF1/CUS2 in Drosophila neural stem cell (neuroblast) lineage formation. We show that Barc is required for the generation of neurons during Drosophila brain development by ensuring correct neural progenitor proliferation and differentiation. Barc associates with components of the U2 small nuclear ribonucleic proteins (snRNP), and its depletion causes alternative splicing in form of intron retention in a subset of genes. Using bioinformatics analysis and a cell culture based splicing assay, we found that Barc-dependent introns share three major traits: they are short, GC rich and have weak 3' splice sites. Our results show that Barc, together with the U2snRNP, plays an important role in regulating neural stem cell lineage progression during brain development and facilitates correct splicing of a subset of introns.
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Affiliation(s)
- Monika K. Abramczuk
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Dr. Bohr-Gasse 3, Vienna, Austria
| | - Thomas R. Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Dr. Bohr-Gasse 3, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Vivien Rolland
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Dr. Bohr-Gasse 3, Vienna, Austria
- Current address: Commonwealth Scientific and Industrial Research Organisation (CSIRO), Agriculture and Food, Canberra, ACT 2601, Australia
| | - Victoria Steinmann
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Dr. Bohr-Gasse 3, Vienna, Austria
| | - Peter Duchek
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Dr. Bohr-Gasse 3, Vienna, Austria
| | - Yanrui Jiang
- Biozentrum, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland
- Current address: D-BSSE ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Sebastian Wissel
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Dr. Bohr-Gasse 3, Vienna, Austria
| | - Heinrich Reichert
- Biozentrum, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland
| | - Juergen A. Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Dr. Bohr-Gasse 3, Vienna, Austria
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Schlackow M, Nojima T, Gomes T, Dhir A, Carmo-Fonseca M, Proudfoot NJ. Distinctive Patterns of Transcription and RNA Processing for Human lincRNAs. Mol Cell 2016; 65:25-38. [PMID: 28017589 PMCID: PMC5222723 DOI: 10.1016/j.molcel.2016.11.029] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/19/2016] [Accepted: 11/17/2016] [Indexed: 12/27/2022]
Abstract
Numerous long intervening noncoding RNAs (lincRNAs) are generated from the mammalian genome by RNA polymerase II (Pol II) transcription. Although multiple functions have been ascribed to lincRNAs, their synthesis and turnover remain poorly characterized. Here, we define systematic differences in transcription and RNA processing between protein-coding and lincRNA genes in human HeLa cells. This is based on a range of nascent transcriptomic approaches applied to different nuclear fractions, including mammalian native elongating transcript sequencing (mNET-seq). Notably, mNET-seq patterns specific for different Pol II CTD phosphorylation states reveal weak co-transcriptional splicing and poly(A) signal-independent Pol II termination of lincRNAs as compared to pre-mRNAs. In addition, lincRNAs are mostly restricted to chromatin, since they are rapidly degraded by the RNA exosome. We also show that a lincRNA-specific co-transcriptional RNA cleavage mechanism acts to induce premature termination. In effect, functional lincRNAs must escape from this targeted nuclear surveillance process.
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Affiliation(s)
- Margarita Schlackow
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
| | - Tomas Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ashish Dhir
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Maria Carmo-Fonseca
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Nick J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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249
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Alternative Splicing of Barley Clock Genes in Response to Low Temperature. PLoS One 2016; 11:e0168028. [PMID: 27959947 PMCID: PMC5154542 DOI: 10.1371/journal.pone.0168028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/23/2016] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing (AS) is a regulated mechanism that generates multiple transcripts from individual genes. It is widespread in eukaryotic genomes and provides an effective way to control gene expression. At low temperatures, AS regulates Arabidopsis clock genes through dynamic changes in the levels of productive mRNAs. We examined AS in barley clock genes to assess whether temperature-dependent AS responses also occur in a monocotyledonous crop species. We identify changes in AS of various barley core clock genes including the barley orthologues of Arabidopsis AtLHY and AtPRR7 which showed the most pronounced AS changes in response to low temperature. The AS events modulate the levels of functional and translatable mRNAs, and potentially protein levels, upon transition to cold. There is some conservation of AS events and/or splicing behaviour of clock genes between Arabidopsis and barley. In addition, novel temperature-dependent AS of the core clock gene HvPPD-H1 (a major determinant of photoperiod response and AtPRR7 orthologue) is conserved in monocots. HvPPD-H1 showed a rapid, temperature-sensitive isoform switch which resulted in changes in abundance of AS variants encoding different protein isoforms. This novel layer of low temperature control of clock gene expression, observed in two very different species, will help our understanding of plant adaptation to different environments and ultimately offer a new range of targets for plant improvement.
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250
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Attig J, Ruiz de Los Mozos I, Haberman N, Wang Z, Emmett W, Zarnack K, König J, Ule J. Splicing repression allows the gradual emergence of new Alu-exons in primate evolution. eLife 2016; 5. [PMID: 27861119 PMCID: PMC5115870 DOI: 10.7554/elife.19545] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/01/2016] [Indexed: 01/01/2023] Open
Abstract
Alu elements are retrotransposons that frequently form new exons during primate evolution. Here, we assess the interplay of splicing repression by hnRNPC and nonsense-mediated mRNA decay (NMD) in the quality control and evolution of new Alu-exons. We identify 3100 new Alu-exons and show that NMD more efficiently recognises transcripts with Alu-exons compared to other exons with premature termination codons. However, some Alu-exons escape NMD, especially when an adjacent intron is retained, highlighting the importance of concerted repression by splicing and NMD. We show that evolutionary progression of 3' splice sites is coupled with longer repressive uridine tracts. Once the 3' splice site at ancient Alu-exons reaches a stable phase, splicing repression by hnRNPC decreases, but the exons generally remain sensitive to NMD. We conclude that repressive motifs are strongest next to cryptic exons and that gradual weakening of these motifs contributes to the evolutionary emergence of new alternative exons.
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Affiliation(s)
- Jan Attig
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom.,MRC-Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Igor Ruiz de Los Mozos
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
| | - Nejc Haberman
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
| | - Zhen Wang
- Institute de Biologie de l'ENS (IBENS), CNRS UMR 8197, Paris, France
| | - Warren Emmett
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom.,University College London Genetics Institute, London, United Kingdom
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Frankfurt, Germany
| | - Julian König
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Jernej Ule
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom.,MRC-Laboratory of Molecular Biology, Cambridge, United Kingdom
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