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Murari E, Meadows D, Cuda N, Mangone M. A comprehensive analysis of 3'UTRs in Caenorhabditis elegans. Nucleic Acids Res 2024; 52:7523-7538. [PMID: 38917330 PMCID: PMC11260456 DOI: 10.1093/nar/gkae543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/29/2024] [Accepted: 06/11/2024] [Indexed: 06/27/2024] Open
Abstract
3'Untranslated regions (3'UTRs) are essential portions of genes containing elements necessary for pre-mRNA 3'end processing and are involved in post-transcriptional gene regulation. Despite their importance, they remain poorly characterized in eukaryotes. Here, we have used a multi-pronged approach to extract and curate 3'UTR data from 11533 publicly available datasets, corresponding to the entire collection of Caenorhabditis elegans transcriptomes stored in the NCBI repository from 2009 to 2023. We have also performed high throughput cloning pipelines to identify and validate rare 3'UTR isoforms and incorporated and manually curated 3'UTR isoforms from previously published datasets. This updated C. elegans 3'UTRome (v3) is the most comprehensive resource in any metazoan to date, covering 97.4% of the 20362 experimentally validated protein-coding genes with refined and updated 3'UTR boundaries for 23489 3'UTR isoforms. We also used this novel dataset to identify and characterize sequence elements involved in pre-mRNA 3'end processing and update miRNA target predictions. This resource provides important insights into the 3'UTR formation, function, and regulation in eukaryotes.
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Affiliation(s)
- Emma Murari
- The Biodesign Institute at Arizona State University, 1001 S McAllister Ave, Tempe, AZ, USA
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ, USA
| | - Dalton Meadows
- The Biodesign Institute at Arizona State University, 1001 S McAllister Ave, Tempe, AZ, USA
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ, USA
| | - Nicholas Cuda
- The Biodesign Institute at Arizona State University, 1001 S McAllister Ave, Tempe, AZ, USA
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ, USA
| | - Marco Mangone
- The Biodesign Institute at Arizona State University, 1001 S McAllister Ave, Tempe, AZ, USA
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2
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Eijlers P, Al-Khafaji M, Soto-Martin E, Fasimoye R, Stead D, Wenzel M, Müller B, Pettitt J. A nematode-specific ribonucleoprotein complex mediates interactions between the major nematode spliced leader snRNP and its target pre-mRNAs. Nucleic Acids Res 2024; 52:7245-7260. [PMID: 38676950 PMCID: PMC11229312 DOI: 10.1093/nar/gkae321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 04/08/2024] [Accepted: 04/12/2024] [Indexed: 04/29/2024] Open
Abstract
Spliced leader trans-splicing of pre-mRNAs is a critical step in the gene expression of many eukaryotes. How the spliced leader RNA and its target transcripts are brought together to form the trans-spliceosome remains an important unanswered question. Using immunoprecipitation followed by protein analysis via mass spectrometry and RIP-Seq, we show that the nematode-specific proteins, SNA-3 and SUT-1, form a complex with a set of enigmatic non-coding RNAs, the SmY RNAs. Our work redefines the SmY snRNP and shows for the first time that it is essential for nematode viability and is involved in spliced leader trans-splicing. SNA-3 and SUT-1 are associated with the 5' ends of most, if not all, nascent capped RNA polymerase II transcripts, and they also interact with components of the major nematode spliced leader (SL1) snRNP. We show that depletion of SNA-3 impairs the co-immunoprecipitation between one of the SL1 snRNP components, SNA-2, and several core spliceosomal proteins. We thus propose that the SmY snRNP recruits the SL1 snRNP to the 5' ends of nascent pre-mRNAs, an instrumental step in the assembly of the trans-spliceosome.
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Affiliation(s)
- Peter Eijlers
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
| | - Mohammed Al-Khafaji
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
| | - Eva Soto-Martin
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
| | - Rotimi Fasimoye
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
| | - David Stead
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Rowett Institute, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
| | - Marius Wenzel
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ Scotland, UK
| | - Berndt Müller
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
| | - Jonathan Pettitt
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD Scotland, UK
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3
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Salcedo-Tacuma D, Asad N, Howells G, Anderson R, Smith DM. Proteasome hyperactivation rewires the proteome enhancing stress resistance, proteostasis, lipid metabolism and ERAD in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588128. [PMID: 38617285 PMCID: PMC11014606 DOI: 10.1101/2024.04.04.588128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Proteasome dysfunction is implicated in the pathogenesis of neurodegenerative diseases and age-related proteinopathies. Using a C. elegans model, we demonstrate that 20S proteasome hyperactivation, facilitated by 20S gate-opening, accelerates the targeting of intrinsically disordered proteins. This leads to increased protein synthesis, extensive rewiring of the proteome and transcriptome, enhanced oxidative stress defense, accelerated lipid metabolism, and peroxisome proliferation. It also promotes ER-associated degradation (ERAD) of aggregation-prone proteins, such as alpha-1 antitrypsin (ATZ) and various lipoproteins. Notably, our results reveal that 20S proteasome hyperactivation suggests a novel role in ERAD with broad implications for proteostasis-related disorders, simultaneously affecting lipid homeostasis and peroxisome proliferation. Furthermore, the enhanced cellular capacity to mitigate proteostasis challenges, alongside unanticipated acceleration of lipid metabolism is expected to contribute to the longevity phenotype of this mutant. Remarkably, the mechanism of longevity induced by 20S gate opening appears unique, independent of known longevity and stress-resistance pathways. These results support the therapeutic potential of 20S proteasome activation in mitigating proteostasis-related disorders broadly and provide new insights into the complex interplay between proteasome activity, cellular health, and aging.
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Affiliation(s)
- David Salcedo-Tacuma
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Nadeeem. Asad
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Giovanni Howells
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - Raymond Anderson
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
| | - David M. Smith
- Department of Biochemistry and Molecular Medicine, West Virginia University School of Medicine, 4 Medical Center Dr., Morgantown, WV USA
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, West Virginia, USA
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4
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Hall AE, Klompstra D, Nance J. C. elegans Afadin is required for epidermal morphogenesis and functionally interfaces with the cadherin-catenin complex and RhoGAP PAC-1/ARHGAP21. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.28.551013. [PMID: 37546884 PMCID: PMC10402129 DOI: 10.1101/2023.07.28.551013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
During epithelial morphogenesis, the apical junctions connecting cells must remodel as cells change shape and make new connections with their neighbors. In the C. elegans embryo, new apical junctions form when epidermal cells migrate and seal with one another to encase the embryo in skin ('ventral enclosure'), and junctions remodel when epidermal cells change shape to squeeze the embryo into a worm shape ('elongation'). The junctional cadherin-catenin complex (CCC), which links epithelial cells to each other and to cortical actomyosin, is essential for C. elegans epidermal morphogenesis. RNAi genetic enhancement screens have identified several proteins that interact with the CCC to promote epidermal morphogenesis, including the scaffolding protein Afadin (AFD-1), whose depletion alone results in only minor morphogenesis defects. Here, by creating a null mutation in afd-1 , we show that afd-1 provides a significant contribution to ventral enclosure and elongation on its own. Unexpectedly, we find that afd-1 mutant phenotypes are strongly modified by diet, revealing a previously unappreciated maternal nutritional input to morphogenesis. We identify functional interactions between AFD-1 and the CCC by demonstrating that E-cadherin is required for the polarized distribution of AFD-1 to cell contact sites in early embryos. Finally, we show that afd-1 promotes the enrichment of polarity regulator and CCC-interacting protein PAC-1/ARHGAP21 to cell contact sites, and identify genetic interactions suggesting that afd-1 and pac-1 regulate epidermal morphogenesis at least in part through parallel mechanisms. Our findings reveal that C. elegans AFD-1 makes a significant contribution to epidermal morphogenesis and functionally interfaces with core and associated CCC proteins.
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Xu J, Du P, Liu X, Xu X, Ge Y, Zhang C. Curcumin supplementation increases longevity and antioxidant capacity in Caenorhabditis elegans. Front Pharmacol 2023; 14:1195490. [PMID: 37346299 PMCID: PMC10279890 DOI: 10.3389/fphar.2023.1195490] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 05/24/2023] [Indexed: 06/23/2023] Open
Abstract
Curcumin is well known as a potent antioxidant and free radical scavenger and has great potential for anti-aging applications. In this study, we investigate the molecular mechanism of curcumin in prolonging the lifespan of C. elegans. Four concentrations of curcumin (10, 25, 50, and 100 µM) were administered, and the optimal treatment concentration was determined by analyzing the nematode lifespan, physiology, and biochemistry. Additionally, RNA-seq and qRT-PCR were performed to explore the antioxidant effect of curcumin and its underlying mechanism. Results revealed that curcumin could significantly improve the survival capacity of C. elegans without influencing its growth. Curcumin was observed to significantly decrease the levels of reactive oxygen species (ROS) under extreme conditions such as heat stress and paraquat stress. In addition, curcumin increased the amount of nematode mitochondrial DNA (mtDNA) replication. RNA-seq results revealed that the underlying mechanism of curcumin in C. elegans is related to the mitogen-activated protein kinase (MAPK) pathway. qRT-PCR results confirmed that the expression of oxidative stress-related genes (sod-1, sod-2, sod-3, gst-4) was increased, and the expression of MAPK signaling pathway-related genes (sek-1, pmk-1, nsy-1) was significantly downregulated. Furthermore, the administration of curcumin extended the lifespan of nematodes, potentially through the enhancement of oxidative stress resistance and the downregulation of the MAPK signaling pathway. These findings improve our understanding of both lifespan extension and the potential mechanism of curcumin in C. elegans.
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Montembault E, Deduyer I, Claverie MC, Bouit L, Tourasse NJ, Dupuy D, McCusker D, Royou A. Two RhoGEF isoforms with distinct localisation control furrow position during asymmetric cell division. Nat Commun 2023; 14:3209. [PMID: 37268622 DOI: 10.1038/s41467-023-38912-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 05/19/2023] [Indexed: 06/04/2023] Open
Abstract
Cytokinesis partitions cellular content between daughter cells. It relies on the formation of an acto-myosin contractile ring, whose constriction induces the ingression of the cleavage furrow between the segregated chromatids. Rho1 GTPase and its RhoGEF (Pbl) are essential for this process. However, how Rho1 is regulated to sustain furrow ingression while maintaining correct furrow position remains poorly defined. Here, we show that during asymmetric division of Drosophila neuroblasts, Rho1 is controlled by two Pbl isoforms with distinct localisation. Spindle midzone- and furrow-enriched Pbl-A focuses Rho1 at the furrow to sustain efficient ingression, while Pbl-B pan-plasma membrane localization promotes the broadening of Rho1 activity and the subsequent enrichment of myosin on the entire cortex. This enlarged zone of Rho1 activity is critical to adjust furrow position, thereby preserving correct daughter cell size asymmetry. Our work highlights how the use of isoforms with distinct localisation makes an essential process more robust.
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Affiliation(s)
- Emilie Montembault
- CNRS, UMR5095, University of Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France
- CNRS, UMR5095, University of Bordeaux, Institut de Biologie et Génétique Cellulaire, 1 rue Camille Saint-Saëns, 33077, Bordeaux, France
| | - Irène Deduyer
- CNRS, UMR5095, University of Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France
- CNRS, UMR5095, University of Bordeaux, Institut de Biologie et Génétique Cellulaire, 1 rue Camille Saint-Saëns, 33077, Bordeaux, France
| | - Marie-Charlotte Claverie
- CNRS, UMR5095, University of Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France
- CNRS, UMR5095, University of Bordeaux, Institut de Biologie et Génétique Cellulaire, 1 rue Camille Saint-Saëns, 33077, Bordeaux, France
| | - Lou Bouit
- CNRS, UMR5095, University of Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France
- CNRS, UMR5297, University of Bordeaux, 146 Rue Léo Saignat, 33076, Bordeaux, France
| | - Nicolas J Tourasse
- University of Bordeaux, INSERM, U1212, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France
| | - Denis Dupuy
- University of Bordeaux, INSERM, U1212, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France
| | - Derek McCusker
- CNRS, UMR5095, University of Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France
- CNRS, UMR5095, University of Bordeaux, Institut de Biologie et Génétique Cellulaire, 1 rue Camille Saint-Saëns, 33077, Bordeaux, France
| | - Anne Royou
- CNRS, UMR5095, University of Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607, Pessac, France.
- CNRS, UMR5095, University of Bordeaux, Institut de Biologie et Génétique Cellulaire, 1 rue Camille Saint-Saëns, 33077, Bordeaux, France.
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7
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Bernard F, Dargère D, Rechavi O, Dupuy D. Quantitative analysis of C. elegans transcripts by Nanopore direct-cDNA sequencing reveals terminal hairpins in non trans-spliced mRNAs. Nat Commun 2023; 14:1229. [PMID: 36869073 PMCID: PMC9984361 DOI: 10.1038/s41467-023-36915-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 02/23/2023] [Indexed: 03/05/2023] Open
Abstract
In nematodes and kinetoplastids, mRNA processing involves a trans-splicing step through which a short sequence from a snRNP replaces the original 5' end of the primary transcript. It has long been held that 70% of C. elegans mRNAs are submitted to trans-splicing. Our recent work suggested that the mechanism is more pervasive but not fully captured by mainstream transcriptome sequencing methods. Here we use Oxford Nanopore's long-read amplification-free sequencing technology to perform a comprehensive analysis of trans-splicing in worms. We demonstrate that spliced leader (SL) sequences at the 5' end of the mRNAs affect library preparation and generate sequencing artefacts due to their self-complementarity. Consistent with our previous observations, we find evidence of trans-splicing for most genes. However, a subset of genes appears to be only marginally trans-spliced. These mRNAs all share the capacity to generate a 5' terminal hairpin structure mimicking the SL structure and offering a mechanistic explanation for their non conformity. Altogether, our data provide a comprehensive quantitative analysis of SL usage in C. elegans.
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Affiliation(s)
- Florian Bernard
- Université de Bordeaux, Inserm U1212, CNRS UMR5320, Institut Européen de Chimie et Biologie (IECB), 2, rue Robert Escarpit, 33607, Pessac, France.,Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Delphine Dargère
- Université de Bordeaux, Inserm U1212, CNRS UMR5320, Institut Européen de Chimie et Biologie (IECB), 2, rue Robert Escarpit, 33607, Pessac, France
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Denis Dupuy
- Université de Bordeaux, Inserm U1212, CNRS UMR5320, Institut Européen de Chimie et Biologie (IECB), 2, rue Robert Escarpit, 33607, Pessac, France.
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8
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Kolathur KK, Sharma P, Kadam NY, Shahi N, Nishitha A, Babu K, Mishra SK. The ubiquitin-like protein Hub1/UBL-5 functions in pre-mRNA splicing in Caenorhabditis elegans. FEBS Lett 2023; 597:448-457. [PMID: 36480405 PMCID: PMC7615767 DOI: 10.1002/1873-3468.14555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
The ubiquitin-like protein Hub1/UBL-5 associates with proteins non-covalently. Hub1 promotes alternative splicing and splicing of precursor mRNAs with weak introns in yeast and mammalian cells; however, its splicing function has remained elusive in multicellular organisms. Here, we demonstrate the splicing function of Hub1/UBL-5 in the free-living nematode Caenorhabditis elegans. Hub1/UBL-5 binds to the HIND-containing splicing factors Snu66/SART-1 and PRP-38 and associates with other spliceosomal proteins. C. elegans hub1/ubl-5 mutants die at the Larval 3 stage and show splicing defects for selected targets, similar to the mutants in yeast and mammalian cells. UBL-5 complemented growth and splicing defects in Schizosaccharomyces pombe hub1 mutants, confirming its functional conservation. Thus, UBL-5 is important for C. elegans development and plays a conserved pre-mRNA splicing function.
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Affiliation(s)
- Kiran Kumar Kolathur
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
- Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences (MCOPS), Manipal Academy of Higher Education (MAHE), India
| | - Pallavi Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Nagesh Y Kadam
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
| | - Navneet Shahi
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Ane Nishitha
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
| | - Kavita Babu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Shravan Kumar Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India
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9
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Fasimoye RY, Spencer R, Soto-Martin E, Eijlers P, Elmassoudi H, Brivio S, Mangana C, Sabele V, Rechtorikova R, Wenzel M, Connolly B, Pettitt J, Müller B. A novel, essential trans-splicing protein connects the nematode SL1 snRNP to the CBC-ARS2 complex. Nucleic Acids Res 2022; 50:7591-7607. [PMID: 35736244 PMCID: PMC9303266 DOI: 10.1093/nar/gkac534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 11/29/2022] Open
Abstract
Spliced leader trans-splicing is essential for gene expression in many eukaryotes. To elucidate the molecular mechanism of this process, we characterise the molecules associated with the Caenorhabditis elegans major spliced leader snRNP (SL1 snRNP), which donates the spliced leader that replaces the 5' untranslated region of most pre-mRNAs. Using a GFP-tagged version of the SL1 snRNP protein SNA-1 created by CRISPR-mediated genome engineering, we immunoprecipitate and identify RNAs and protein components by RIP-Seq and mass spectrometry. This reveals the composition of the SL1 snRNP and identifies associations with spliceosome components PRP-8 and PRP-19. Significantly, we identify a novel, nematode-specific protein required for SL1 trans-splicing, which we designate SNA-3. SNA-3 is an essential, nuclear protein with three NADAR domains whose function is unknown. Mutation of key residues in NADAR domains inactivates the protein, indicating that domain function is required for activity. SNA-3 interacts with the CBC-ARS2 complex and other factors involved in RNA metabolism, including SUT-1 protein, through RNA or protein-mediated contacts revealed by yeast two-hybrid assays, localisation studies and immunoprecipitations. Our data are compatible with a role for SNA-3 in coordinating trans-splicing with target pre-mRNA transcription or in the processing of the Y-branch product of the trans-splicing reaction.
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Affiliation(s)
- Rotimi Yemi Fasimoye
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Rosie Elizabeth Barker Spencer
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Eva Soto-Martin
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Peter Eijlers
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Haitem Elmassoudi
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Sarah Brivio
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Carolina Mangana
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Viktorija Sabele
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Radoslava Rechtorikova
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Marius Wenzel
- Centre of Genome-Enabled Biology and Medicine, University of Aberdeen, 23 St Machar Drive, Aberdeen AB24 3RY, Scotland, UK
| | - Bernadette Connolly
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Jonathan Pettitt
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Berndt Müller
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
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10
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Jhaveri N, van den Berg W, Hwang BJ, Muller HM, Sternberg PW, Gupta BP. Genome annotation of Caenorhabditis briggsae by TEC-RED identifies new exons, paralogs, and conserved and novel operons. G3 (BETHESDA, MD.) 2022; 12:jkac101. [PMID: 35485953 PMCID: PMC9258526 DOI: 10.1093/g3journal/jkac101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 04/14/2022] [Indexed: 11/14/2022]
Abstract
The nematode Caenorhabditis briggsae is routinely used in comparative and evolutionary studies involving its well-known cousin Caenorhabditis elegans. The C. briggsae genome sequence has accelerated research by facilitating the generation of new resources, tools, and functional studies of genes. While substantial progress has been made in predicting genes and start sites, experimental evidence is still lacking in many cases. Here, we report an improved annotation of the C. briggsae genome using the trans-spliced exon coupled RNA end determination technique. In addition to identifying the 5' ends of expressed genes, we have discovered operons and paralogs. In summary, our analysis yielded 10,243 unique 5' end sequence tags with matches in the C. briggsae genome. Of these, 6,395 were found to represent 4,252 unique genes along with 362 paralogs and 52 previously unknown exons. These genes included 14 that are exclusively trans-spliced in C. briggsae when compared with C. elegans orthologs. A major contribution of this study is the identification of 492 high confidence operons, of which two-thirds are fully supported by tags. In addition, 2 SL1-type operons were discovered. Interestingly, comparisons with C. elegans showed that only 40% of operons are conserved. Of the remaining operons, 73 are novel, including 12 that entirely lack orthologs in C. elegans. Further analysis revealed that 4 of the 12 novel operons are conserved in Caenorhabditis nigoni. Altogether, the work described here has significantly advanced our understanding of the C. briggsae system and serves as a rich resource to aid biological studies involving this species.
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Affiliation(s)
- Nikita Jhaveri
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | | | - Byung Joon Hwang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hans-Michael Muller
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Bhagwati P Gupta
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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11
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Floxed exon (Flexon): A flexibly positioned stop cassette for recombinase-mediated conditional gene expression. Proc Natl Acad Sci U S A 2022; 119:2117451119. [PMID: 35027456 PMCID: PMC8784106 DOI: 10.1073/pnas.2117451119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2021] [Indexed: 12/15/2022] Open
Abstract
Tools that afford spatiotemporal control of gene expression are crucial for studying genes and processes in multicellular organisms. Stop cassettes consist of exogenous sequences that interrupt gene expression and flanking site-specific recombinase sites to allow for tissue-specific excision and restoration of function by expression of the cognate recombinase. We describe a stop cassette called a flexon, composed of an artificial exon flanked by artificial introns that can be flexibly positioned in a gene. We demonstrate its efficacy in Caenorhabditis elegans for lineage-specific control of gene expression and for tissue-specific RNA interference and discuss other potential uses. The Flexon approach should be feasible in any system amenable to site-specific recombination-based methods and applicable to diverse areas including development, neuroscience, and metabolism. Conditional gene expression is a powerful tool for genetic analysis of biological phenomena. In the widely used “lox-stop-lox” approach, insertion of a stop cassette consisting of a series of stop codons and polyadenylation signals flanked by lox sites into the 5′ untranslated region (UTR) of a gene prevents expression until the cassette is excised by tissue-specific expression of Cre recombinase. Although lox-stop-lox and similar approaches using other site-specific recombinases have been successfully used in many experimental systems, this design has certain limitations. Here, we describe the Floxed exon (Flexon) approach, which uses a stop cassette composed of an artificial exon flanked by artificial introns, designed to cause premature termination of translation and nonsense-mediated decay of the mRNA and allowing for flexible placement into a gene. We demonstrate its efficacy in Caenorhabditis elegans by showing that, when promoters that cause weak and/or transient cell-specific expression are used to drive Cre in combination with a gfp(flexon) transgene, strong and sustained expression of green fluorescent protein (GFP) is obtained in specific lineages. We also demonstrate its efficacy in an endogenous gene context: we inserted a flexon into the Argonaute gene rde-1 to abrogate RNA interference (RNAi), and restored RNAi tissue specifically by expression of Cre. Finally, we describe several potential additional applications of the Flexon approach, including more precise control of gene expression using intersectional methods, tissue-specific protein degradation, and generation of genetic mosaics. The Flexon approach should be feasible in any system where a site-specific recombination-based method may be applied.
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12
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Ham S, Kim SS, Park S, Kim EJE, Kwon S, Park HEH, Jung Y, Lee SJV. Systematic transcriptome analysis associated with physiological and chronological aging in Caenorhabditis elegans. Genome Res 2022; 32:2003-2014. [PMID: 36351769 PMCID: PMC9808617 DOI: 10.1101/gr.276515.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 10/19/2022] [Indexed: 11/11/2022]
Abstract
Aging is associated with changes in a variety of biological processes at the transcriptomic level, including gene expression. Two types of aging occur during a lifetime: chronological and physiological aging. However, dissecting the difference between chronological and physiological ages at the transcriptomic level has been a challenge because of its complexity. We analyzed the transcriptomic features associated with physiological and chronological aging using Caenorhabditis elegans as a model. Many structural and functional transcript elements, such as noncoding RNAs and intron-derived transcripts, were up-regulated with chronological aging. In contrast, mRNAs with many biological functions, including RNA processing, were down-regulated with physiological aging. We also identified an age-dependent increase in the usage of distal 3' splice sites in mRNA transcripts as a biomarker of physiological aging. Our study provides crucial information for dissecting chronological and physiological aging at the transcriptomic level.
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13
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Katsanos D, Ferrando-Marco M, Razzaq I, Aughey G, Southall TD, Barkoulas M. Gene expression profiling of epidermal cell types in C. elegans using Targeted DamID. Development 2021; 148:dev199452. [PMID: 34397094 PMCID: PMC7613258 DOI: 10.1242/dev.199452] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 08/05/2021] [Indexed: 12/19/2022]
Abstract
The epidermis of Caenorhabditis elegans is an essential tissue for survival because it contributes to the formation of the cuticle barrier as well as facilitating developmental progression and animal growth. Most of the epidermis consists of the hyp7 hypodermal syncytium, the nuclei of which are largely generated by the seam cells, which exhibit stem cell-like behaviour during development. How seam cell progenitors differ transcriptionally from the differentiated hypodermis is poorly understood. Here, we introduce Targeted DamID (TaDa) in C. elegans as a method for identifying genes expressed within a tissue of interest without cell isolation. We show that TaDa signal enrichment profiles can be used to identify genes transcribed in the epidermis and use this method to resolve differences in gene expression between the seam cells and the hypodermis. Finally, we predict and functionally validate new transcription and chromatin factors acting in seam cell development. These findings provide insights into cell type-specific gene expression profiles likely associated with epidermal cell fate patterning.
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Affiliation(s)
- Dimitris Katsanos
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Mar Ferrando-Marco
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Iqrah Razzaq
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Gabriel Aughey
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Tony D. Southall
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Michalis Barkoulas
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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14
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Karousis ED, Gypas F, Zavolan M, Mühlemann O. Nanopore sequencing reveals endogenous NMD-targeted isoforms in human cells. Genome Biol 2021; 22:223. [PMID: 34389041 PMCID: PMC8361881 DOI: 10.1186/s13059-021-02439-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Nonsense-mediated mRNA decay (NMD) is a eukaryotic, translation-dependent degradation pathway that targets mRNAs with premature termination codons and also regulates the expression of some mRNAs that encode full-length proteins. Although many genes express NMD-sensitive transcripts, identifying them based on short-read sequencing data remains a challenge. RESULTS To identify and analyze endogenous targets of NMD, we apply cDNA Nanopore sequencing and short-read sequencing to human cells with varying expression levels of NMD factors. Our approach detects full-length NMD substrates that are highly unstable and increase in levels or even only appear when NMD is inhibited. Among the many new NMD-targeted isoforms that our analysis identifies, most derive from alternative exon usage. The isoform-aware analysis reveals many genes with significant changes in splicing but no significant changes in overall expression levels upon NMD knockdown. NMD-sensitive mRNAs have more exons in the 3΄UTR and, for those mRNAs with a termination codon in the last exon, the length of the 3΄UTR per se does not correlate with NMD sensitivity. Analysis of splicing signals reveals isoforms where NMD has been co-opted in the regulation of gene expression, though the main function of NMD seems to be ridding the transcriptome of isoforms resulting from spurious splicing events. CONCLUSIONS Long-read sequencing enables the identification of many novel NMD-sensitive mRNAs and reveals both known and unexpected features concerning their biogenesis and their biological role. Our data provide a highly valuable resource of human NMD transcript targets for future genomic and transcriptomic applications.
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Affiliation(s)
- Evangelos D Karousis
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Foivos Gypas
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
| | - Mihaela Zavolan
- Biozentrum, University of Basel and Swiss Institute of Bioinformatics, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland.
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15
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Taylor SR, Santpere G, Weinreb A, Barrett A, Reilly MB, Xu C, Varol E, Oikonomou P, Glenwinkel L, McWhirter R, Poff A, Basavaraju M, Rafi I, Yemini E, Cook SJ, Abrams A, Vidal B, Cros C, Tavazoie S, Sestan N, Hammarlund M, Hobert O, Miller DM. Molecular topography of an entire nervous system. Cell 2021; 184:4329-4347.e23. [PMID: 34237253 DOI: 10.1016/j.cell.2021.06.023] [Citation(s) in RCA: 280] [Impact Index Per Article: 93.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/09/2021] [Accepted: 06/14/2021] [Indexed: 02/08/2023]
Abstract
We have produced gene expression profiles of all 302 neurons of the C. elegans nervous system that match the single-cell resolution of its anatomy and wiring diagram. Our results suggest that individual neuron classes can be solely identified by combinatorial expression of specific gene families. For example, each neuron class expresses distinct codes of ∼23 neuropeptide genes and ∼36 neuropeptide receptors, delineating a complex and expansive "wireless" signaling network. To demonstrate the utility of this comprehensive gene expression catalog, we used computational approaches to (1) identify cis-regulatory elements for neuron-specific gene expression and (2) reveal adhesion proteins with potential roles in process placement and synaptic specificity. Our expression data are available at https://cengen.org and can be interrogated at the web application CengenApp. We expect that this neuron-specific directory of gene expression will spur investigations of underlying mechanisms that define anatomy, connectivity, and function throughout the C. elegans nervous system.
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Affiliation(s)
- Seth R Taylor
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gabriel Santpere
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Neurogenomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM), DCEXS, Universitat Pompeu Fabra, 08003 Barcelona, Catalonia, Spain
| | - Alexis Weinreb
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Alec Barrett
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Molly B Reilly
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Chuan Xu
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Erdem Varol
- Department of Statistics, Columbia University, New York, NY, USA
| | - Panos Oikonomou
- Department of Biological Sciences, Columbia University, New York, NY, USA; Department of Systems Biology, Columbia University Medical Center, New York, NY, USA
| | - Lori Glenwinkel
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Rebecca McWhirter
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Abigail Poff
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Manasa Basavaraju
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Ibnul Rafi
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Eviatar Yemini
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Steven J Cook
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Alexander Abrams
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Berta Vidal
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Cyril Cros
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Saeed Tavazoie
- Department of Biological Sciences, Columbia University, New York, NY, USA; Department of Systems Biology, Columbia University Medical Center, New York, NY, USA
| | - Nenad Sestan
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Marc Hammarlund
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, New York, NY, USA; Howard Hughes Medical Institute, Columbia University, New York, NY, USA.
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Program in Neuroscience, Vanderbilt University School of Medicine, Nashville, TN, USA.
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16
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Watabe E, Togo-Ohno M, Ishigami Y, Wani S, Hirota K, Kimura-Asami M, Hasan S, Takei S, Fukamizu A, Suzuki Y, Suzuki T, Kuroyanagi H. m 6 A-mediated alternative splicing coupled with nonsense-mediated mRNA decay regulates SAM synthetase homeostasis. EMBO J 2021; 40:e106434. [PMID: 34152017 DOI: 10.15252/embj.2020106434] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 04/29/2021] [Accepted: 05/07/2021] [Indexed: 12/24/2022] Open
Abstract
Alternative splicing of pre-mRNAs can regulate gene expression levels by coupling with nonsense-mediated mRNA decay (NMD). In order to elucidate a repertoire of mRNAs regulated by alternative splicing coupled with NMD (AS-NMD) in an organism, we performed long-read RNA sequencing of poly(A)+ RNAs from an NMD-deficient mutant strain of Caenorhabditis elegans, and obtained full-length sequences for mRNA isoforms from 259 high-confidence AS-NMD genes. Among them are the S-adenosyl-L-methionine (SAM) synthetase (sams) genes sams-3 and sams-4. SAM synthetase activity autoregulates sams gene expression through AS-NMD in a negative feedback loop. We furthermore find that METT-10, the orthologue of human U6 snRNA methyltransferase METTL16, is required for the splicing regulation in␣vivo, and specifically methylates the invariant AG dinucleotide at the distal 3' splice site (3'SS) in␣vitro. Direct RNA sequencing coupled with machine learning confirms m6 A modification of endogenous sams mRNAs. Overall, these results indicate that homeostasis of SAM synthetase in C. elegans is maintained by alternative splicing regulation through m6 A modification at the 3'SS of the sams genes.
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Affiliation(s)
- Eichi Watabe
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Marina Togo-Ohno
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Yuma Ishigami
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shotaro Wani
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Keiko Hirota
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba-shi, Ibaraki, Japan
| | - Mariko Kimura-Asami
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Sharmin Hasan
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Satomi Takei
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Akiyoshi Fukamizu
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba-shi, Ibaraki, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa-shi, Chiba, Japan
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan.,Department of Biochemistry, Graduate School of Medicine, University of the Ryukyus, Nishihara-cho, Okinawa, Japan
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17
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Wenzel MA, Müller B, Pettitt J. SLIDR and SLOPPR: flexible identification of spliced leader trans-splicing and prediction of eukaryotic operons from RNA-Seq data. BMC Bioinformatics 2021; 22:140. [PMID: 33752599 PMCID: PMC7986045 DOI: 10.1186/s12859-021-04009-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/08/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Spliced leader (SL) trans-splicing replaces the 5' end of pre-mRNAs with the spliced leader, an exon derived from a specialised non-coding RNA originating from elsewhere in the genome. This process is essential for resolving polycistronic pre-mRNAs produced by eukaryotic operons into monocistronic transcripts. SL trans-splicing and operons may have independently evolved multiple times throughout Eukarya, yet our understanding of these phenomena is limited to only a few well-characterised organisms, most notably C. elegans and trypanosomes. The primary barrier to systematic discovery and characterisation of SL trans-splicing and operons is the lack of computational tools for exploiting the surge of transcriptomic and genomic resources for a wide range of eukaryotes. RESULTS Here we present two novel pipelines that automate the discovery of SLs and the prediction of operons in eukaryotic genomes from RNA-Seq data. SLIDR assembles putative SLs from 5' read tails present after read alignment to a reference genome or transcriptome, which are then verified by interrogating corresponding SL RNA genes for sequence motifs expected in bona fide SL RNA molecules. SLOPPR identifies RNA-Seq reads that contain a given 5' SL sequence, quantifies genome-wide SL trans-splicing events and predicts operons via distinct patterns of SL trans-splicing events across adjacent genes. We tested both pipelines with organisms known to carry out SL trans-splicing and organise their genes into operons, and demonstrate that (1) SLIDR correctly detects expected SLs and often discovers novel SL variants; (2) SLOPPR correctly identifies functionally specialised SLs, correctly predicts known operons and detects plausible novel operons. CONCLUSIONS SLIDR and SLOPPR are flexible tools that will accelerate research into the evolutionary dynamics of SL trans-splicing and operons throughout Eukarya and improve gene discovery and annotation for a wide range of eukaryotic genomes. Both pipelines are implemented in Bash and R and are built upon readily available software commonly installed on most bioinformatics servers. Biological insight can be gleaned even from sparse, low-coverage datasets, implying that an untapped wealth of information can be retrieved from existing RNA-Seq datasets as well as from novel full-isoform sequencing protocols as they become more widely available.
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Affiliation(s)
- Marius A Wenzel
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK.
| | - Berndt Müller
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Jonathan Pettitt
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, UK
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18
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Wenzel M, Johnston C, Müller B, Pettitt J, Connolly B. Resolution of polycistronic RNA by SL2 trans-splicing is a widely conserved nematode trait. RNA (NEW YORK, N.Y.) 2020; 26:1891-1904. [PMID: 32887788 PMCID: PMC7668243 DOI: 10.1261/rna.076414.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Spliced leader trans-splicing is essential for the processing and translation of polycistronic RNAs generated by eukaryotic operons. In C. elegans, a specialized spliced leader, SL2, provides the 5' end for uncapped pre-mRNAs derived from polycistronic RNAs. Studies of other nematodes suggested that SL2-type trans-splicing is a relatively recent innovation, confined to Rhabditina, the clade containing C. elegans and its close relatives. Here we conduct a survey of transcriptome-wide spliced leader trans-splicing in Trichinella spiralis, a distant relative of C. elegans with a particularly diverse repertoire of 15 spliced leaders. By systematically comparing the genomic context of trans-splicing events for each spliced leader, we identified a subset of T. spiralis spliced leaders that are specifically used to process polycistronic RNAs-the first examples of SL2-type spliced leaders outside of Rhabditina. These T. spiralis spliced leader RNAs possess a perfectly conserved stem-loop motif previously shown to be essential for SL2-type trans-splicing in C. elegans We show that genes trans-spliced to these SL2-type spliced leaders are organized in operonic fashion, with short intercistronic distances. A subset of T. spiralis operons show conservation of synteny with C. elegans operons. Our work substantially revises our understanding of nematode spliced leader trans-splicing, showing that SL2 trans-splicing is a major mechanism for nematode polycistronic RNA processing, which may have evolved prior to the radiation of the Nematoda. This work has important implications for the improvement of genome annotation pipelines in nematodes and other eukaryotes with operonic gene organization.
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Affiliation(s)
- Marius Wenzel
- Centre of Genome-Enabled Biology and Medicine, University of Aberdeen, Aberdeen AB24 3RY, United Kingdom
| | - Christopher Johnston
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Berndt Müller
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Jonathan Pettitt
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernadette Connolly
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
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19
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Koterniak B, Pilaka PP, Gracida X, Schneider LM, Pritišanac I, Zhang Y, Calarco JA. Global regulatory features of alternative splicing across tissues and within the nervous system of C. elegans. Genome Res 2020; 30:1766-1780. [PMID: 33127752 PMCID: PMC7706725 DOI: 10.1101/gr.267328.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/28/2020] [Indexed: 12/27/2022]
Abstract
Alternative splicing plays a major role in shaping tissue-specific transcriptomes. Among the broad tissue types present in metazoans, the central nervous system contains some of the highest levels of alternative splicing. Although many documented examples of splicing differences between broad tissue types exist, there remains much to be understood about the splicing factors and the cis sequence elements controlling tissue and neuron subtype-specific splicing patterns. By using translating ribosome affinity purification coupled with deep-sequencing (TRAP-seq) in Caenorhabditis elegans, we have obtained high coverage profiles of ribosome-associated mRNA for three broad tissue classes (nervous system, muscle, and intestine) and two neuronal subtypes (dopaminergic and serotonergic neurons). We have identified hundreds of splice junctions that exhibit distinct splicing patterns between tissue types or within the nervous system. Alternative splicing events differentially regulated between tissues are more often frame-preserving, are more highly conserved across Caenorhabditis species, and are enriched in specific cis regulatory motifs, when compared with other types of exons. By using this information, we have identified a likely mechanism of splicing repression by the RNA-binding protein UNC-75/CELF via interactions with cis elements that overlap a 5′ splice site. Alternatively spliced exons also overlap more frequently with intrinsically disordered peptide regions than constitutive exons. Moreover, regulated exons are often shorter than constitutive exons but are flanked by longer intron sequences. Among these tissue-regulated exons are several highly conserved microexons <27 nt in length. Collectively, our results indicate a rich layer of tissue-specific gene regulation at the level of alternative splicing in C. elegans that parallels the evolutionary forces and constraints observed across metazoa.
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Affiliation(s)
- Bina Koterniak
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Pallavi P Pilaka
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Xicotencatl Gracida
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Lisa-Marie Schneider
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Department of Chemistry, University of Bayreuth, 95447 Bayreuth, Germany
| | - Iva Pritišanac
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Yun Zhang
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - John A Calarco
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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20
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Arribere JA, Kuroyanagi H, Hundley HA. mRNA Editing, Processing and Quality Control in Caenorhabditis elegans. Genetics 2020; 215:531-568. [PMID: 32632025 PMCID: PMC7337075 DOI: 10.1534/genetics.119.301807] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 05/03/2020] [Indexed: 02/06/2023] Open
Abstract
While DNA serves as the blueprint of life, the distinct functions of each cell are determined by the dynamic expression of genes from the static genome. The amount and specific sequences of RNAs expressed in a given cell involves a number of regulated processes including RNA synthesis (transcription), processing, splicing, modification, polyadenylation, stability, translation, and degradation. As errors during mRNA production can create gene products that are deleterious to the organism, quality control mechanisms exist to survey and remove errors in mRNA expression and processing. Here, we will provide an overview of mRNA processing and quality control mechanisms that occur in Caenorhabditis elegans, with a focus on those that occur on protein-coding genes after transcription initiation. In addition, we will describe the genetic and technical approaches that have allowed studies in C. elegans to reveal important mechanistic insight into these processes.
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Affiliation(s)
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan, and
| | - Heather A Hundley
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Indiana 47405
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21
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Li R, Ren X, Ding Q, Bi Y, Xie D, Zhao Z. Direct full-length RNA sequencing reveals unexpected transcriptome complexity during Caenorhabditis elegans development. Genome Res 2020; 30:287-298. [PMID: 32024662 PMCID: PMC7050527 DOI: 10.1101/gr.251512.119] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 12/18/2019] [Indexed: 01/08/2023]
Abstract
Massively parallel sequencing of the polyadenylated RNAs has played a key role in delineating transcriptome complexity, including alternative use of an exon, promoter, 5′ or 3′ splice site or polyadenylation site, and RNA modification. However, reads derived from the current RNA-seq technologies are usually short and deprived of information on modification, compromising their potential in defining transcriptome complexity. Here, we applied a direct RNA sequencing method with ultralong reads using Oxford Nanopore Technologies to study the transcriptome complexity in Caenorhabditis elegans. We generated approximately six million reads using native poly(A)-tailed mRNAs from three developmental stages, with average read lengths ranging from 900 to 1100 nt. Around half of the reads represent full-length transcripts. To utilize the full-length transcripts in defining transcriptome complexity, we devised a method to classify the long reads as the same as existing transcripts or as a novel transcript using sequence mapping tracks rather than existing intron/exon structures, which allowed us to identify roughly 57,000 novel isoforms and recover at least 26,000 out of the 33,500 existing isoforms. The sets of genes with differential expression versus differential isoform usage over development are largely different, implying a fine-tuned regulation at isoform level. We also observed an unexpected increase in putative RNA modification in all bases in the coding region relative to the UTR, suggesting their possible roles in translation. The RNA reads and the method for read classification are expected to deliver new insights into RNA processing and modification and their underlying biology in the future.
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Affiliation(s)
- Runsheng Li
- Department of Biology, Hong Kong Baptist University, Hong Kong, 999077, China
| | - Xiaoliang Ren
- Department of Biology, Hong Kong Baptist University, Hong Kong, 999077, China
| | - Qiutao Ding
- Department of Biology, Hong Kong Baptist University, Hong Kong, 999077, China
| | - Yu Bi
- Department of Biology, Hong Kong Baptist University, Hong Kong, 999077, China
| | - Dongying Xie
- Department of Biology, Hong Kong Baptist University, Hong Kong, 999077, China
| | - Zhongying Zhao
- Department of Biology, Hong Kong Baptist University, Hong Kong, 999077, China.,State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong, 999077, China
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22
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Roach NP, Sadowski N, Alessi AF, Timp W, Taylor J, Kim JK. The full-length transcriptome of C. elegans using direct RNA sequencing. Genome Res 2020; 30:299-312. [PMID: 32024661 PMCID: PMC7050520 DOI: 10.1101/gr.251314.119] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 01/06/2020] [Indexed: 12/31/2022]
Abstract
Current transcriptome annotations have largely relied on short read lengths intrinsic to the most widely used high-throughput cDNA sequencing technologies. For example, in the annotation of the Caenorhabditis elegans transcriptome, more than half of the transcript isoforms lack full-length support and instead rely on inference from short reads that do not span the full length of the isoform. We applied nanopore-based direct RNA sequencing to characterize the developmental polyadenylated transcriptome of C. elegans Taking advantage of long reads spanning the full length of mRNA transcripts, we provide support for 23,865 splice isoforms across 14,611 genes, without the need for computational reconstruction of gene models. Of the isoforms identified, 3452 are novel splice isoforms not present in the WormBase WS265 annotation. Furthermore, we identified 16,342 isoforms in the 3' untranslated region (3' UTR), 2640 of which are novel and do not fall within 10 bp of existing 3'-UTR data sets and annotations. Combining 3' UTRs and splice isoforms, we identified 28,858 full-length transcript isoforms. We also determined that poly(A) tail lengths of transcripts vary across development, as do the strengths of previously reported correlations between poly(A) tail length and expression level, and poly(A) tail length and 3'-UTR length. Finally, we have formatted this data as a publicly accessible track hub, enabling researchers to explore this data set easily in a genome browser.
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Affiliation(s)
- Nathan P Roach
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Norah Sadowski
- Department of Biomedical Engineering, Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Amelia F Alessi
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Winston Timp
- Department of Biomedical Engineering, Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - James Taylor
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - John K Kim
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
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23
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Serobyan V, Kontarakis Z, El-Brolosy MA, Welker JM, Tolstenkov O, Saadeldein AM, Retzer N, Gottschalk A, Wehman AM, Stainier DY. Transcriptional adaptation in Caenorhabditis elegans. eLife 2020; 9:50014. [PMID: 31951195 PMCID: PMC6968918 DOI: 10.7554/elife.50014] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 01/02/2020] [Indexed: 02/06/2023] Open
Abstract
Transcriptional adaptation is a recently described phenomenon by which a mutation in one gene leads to the transcriptional modulation of related genes, termed adapting genes. At the molecular level, it has been proposed that the mutant mRNA, rather than the loss of protein function, activates this response. While several examples of transcriptional adaptation have been reported in zebrafish embryos and in mouse cell lines, it is not known whether this phenomenon is observed across metazoans. Here we report transcriptional adaptation in C. elegans, and find that this process requires factors involved in mutant mRNA decay, as in zebrafish and mouse. We further uncover a requirement for Argonaute proteins and Dicer, factors involved in small RNA maturation and transport into the nucleus. Altogether, these results provide evidence for transcriptional adaptation in C. elegans, a powerful model to further investigate underlying molecular mechanisms.
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Affiliation(s)
- Vahan Serobyan
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Zacharias Kontarakis
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Mohamed A El-Brolosy
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Jordan M Welker
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Oleg Tolstenkov
- Institute for Biophysical Chemistry, Goethe University, Frankfurt Am Main, Germany.,Cluster of Excellence Frankfurt - Macromolecular Complexes (CEF-MC), Goethe University, Frankfurt Am Main, Germany
| | - Amr M Saadeldein
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Nicholas Retzer
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Alexander Gottschalk
- Institute for Biophysical Chemistry, Goethe University, Frankfurt Am Main, Germany.,Cluster of Excellence Frankfurt - Macromolecular Complexes (CEF-MC), Goethe University, Frankfurt Am Main, Germany.,Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt Am Main, Germany
| | - Ann M Wehman
- Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | - Didier Yr Stainier
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
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24
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The C. elegans 3' UTRome v2 resource for studying mRNA cleavage and polyadenylation, 3'-UTR biology, and miRNA targeting. Genome Res 2019; 29:2104-2116. [PMID: 31744903 PMCID: PMC6886508 DOI: 10.1101/gr.254839.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/10/2019] [Indexed: 12/11/2022]
Abstract
3′ Untranslated regions (3′ UTRs) of mRNAs emerged as central regulators of cellular function because they contain important but poorly characterized cis-regulatory elements targeted by a multitude of regulatory factors. The model nematode Caenorhabditis elegans is ideal to study these interactions because it possesses a well-defined 3′ UTRome. To improve its annotation, we have used a genome-wide bioinformatics approach to download raw transcriptome data for 1088 transcriptome data sets corresponding to the entire collection of C. elegans trancriptomes from 2015 to 2018 from the Sequence Read Archive at the NCBI. We then extracted and mapped high-quality 3′-UTR data at ultradeep coverage. Here, we describe and release to the community the updated version of the worm 3′ UTRome, which we named 3′ UTRome v2. This resource contains high-quality 3′-UTR data mapped at single-base ultraresolution for 23,084 3′-UTR isoform variants corresponding to 14,788 protein-coding genes and is updated to the latest release of WormBase. We used this data set to study and probe principles of mRNA cleavage and polyadenylation in C. elegans. The worm 3′ UTRome v2 represents the most comprehensive and high-resolution 3′-UTR data set available in C. elegans and provides a novel resource to investigate the mRNA cleavage and polyadenylation reaction, 3′-UTR biology, and miRNA targeting in a living organism.
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25
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Ye C, Zhou Q, Wu X, Ji G, Li QQ. Genome-wide alternative polyadenylation dynamics in response to biotic and abiotic stresses in rice. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 183:109485. [PMID: 31376807 DOI: 10.1016/j.ecoenv.2019.109485] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 05/24/2023]
Abstract
Alternative polyadenylation (APA) is an important way to regulate gene expression at the post-transcriptional level, and is extensively involved in plant stress responses. However, the systematic roles of APA regulation in response to abiotic and biotic stresses in rice at the genome scale remain unknown. To take advantage of available RNA-seq datasets, using a novel tool APAtrap, we identified thousands of genes with significantly differential usage of polyadenylation [poly(A)] sites in response to the abiotic stress (drought, heat shock, and cadmium) and biotic stress [bacterial blight (BB), rice blast, and rice stripe virus (RSV)]. Genes with stress-responsive APA dynamics commonly exhibited higher expression levels when their isoforms with short 3' untranslated region (3' UTR) were more abundant. The stress-responsive APA events were widely involved in crucial stress-responsive genes and pathways: e.g. APA acted as a negative regulator in heat stress tolerance; APA events were involved in DNA repair and cell wall formation under Cd stress; APA regulated chlorophyll metabolism, being associated with the pathogenesis of leaf diseases under RSV and BB challenges. Furthermore, APA events were found to be involved in glutathione metabolism and MAPK signaling pathways, mediating a crosstalk among the abiotic and biotic stress-responsive regulatory networks in rice. Analysis of large-scale datasets revealed that APA may regulate abiotic and biotic stress-responsive processes in rice. Such post-transcriptome diversities contribute to rice adaption to various environmental challenges. Our study would supply useful resource for further molecular assisted breeding of multiple stress-tolerant cultivars for rice.
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Affiliation(s)
- Congting Ye
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361102, China.
| | - Qian Zhou
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361102, China; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, 91766, USA.
| | - Xiaohui Wu
- Department of Automation, Xiamen University, Xiamen, Fujian, 361005, China.
| | - Guoli Ji
- Department of Automation, Xiamen University, Xiamen, Fujian, 361005, China.
| | - Qingshun Quinn Li
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361102, China; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, 91766, USA.
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26
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CRISPR editing of sftb-1/SF3B1 in Caenorhabditis elegans allows the identification of synthetic interactions with cancer-related mutations and the chemical inhibition of splicing. PLoS Genet 2019; 15:e1008464. [PMID: 31634348 PMCID: PMC6830814 DOI: 10.1371/journal.pgen.1008464] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/05/2019] [Accepted: 10/05/2019] [Indexed: 12/23/2022] Open
Abstract
SF3B1 is the most frequently mutated splicing factor in cancer. Mutations in SF3B1 likely confer clonal advantages to cancer cells but they may also confer vulnerabilities that can be therapeutically targeted. SF3B1 cancer mutations can be maintained in homozygosis in C. elegans, allowing synthetic lethal screens with a homogeneous population of animals. These mutations cause alternative splicing (AS) defects in C. elegans, as it occurs in SF3B1-mutated human cells. In a screen, we identified RNAi of U2 snRNP components that cause synthetic lethality with sftb-1/SF3B1 mutations. We also detected synthetic interactions between sftb-1 mutants and cancer-related mutations in uaf-2/U2AF1 or rsp-4/SRSF2, demonstrating that this model can identify interactions between mutations that are mutually exclusive in human tumors. Finally, we have edited an SFTB-1 domain to sensitize C. elegans to the splicing modulators pladienolide B and herboxidiene. Thus, we have established a multicellular model for SF3B1 mutations amenable for high-throughput genetic and chemical screens.
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27
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Warner AD, Gevirtzman L, Hillier LW, Ewing B, Waterston RH. The C. elegans embryonic transcriptome with tissue, time, and alternative splicing resolution. Genome Res 2019; 29:1036-1045. [PMID: 31123079 PMCID: PMC6581053 DOI: 10.1101/gr.243394.118] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 03/11/2019] [Indexed: 12/22/2022]
Abstract
We have used RNA-seq in Caenorhabditis elegans to produce transcription profiles for seven specific embryonic cell populations from gastrulation to the onset of terminal differentiation. The expression data for these seven cell populations, covering major cell lineages and tissues in the worm, reveal the complex and dynamic changes in gene expression, both spatially and temporally. Also, within genes, start sites and exon usage can be highly differential, producing transcripts that are specific to developmental periods or cell lineages. We have also found evidence of novel exons and introns, as well as differential usage of SL1 and SL2 splice leaders. By combining this data set with the modERN ChIP-seq resource, we are able to support and predict gene regulatory relationships. The detailed information on differences and similarities between gene expression in cell lineages and tissues should be of great value to the community and provides a framework for the investigation of expression in individual cells.
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Affiliation(s)
- Adam D Warner
- Department of Genome Sciences, School of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Louis Gevirtzman
- Department of Genome Sciences, School of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - LaDeana W Hillier
- Department of Genome Sciences, School of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Brent Ewing
- Department of Genome Sciences, School of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Robert H Waterston
- Department of Genome Sciences, School of Medicine, University of Washington, Seattle, Washington 98195, USA
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28
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Barnes SN, Masonbrink RE, Maier TR, Seetharam A, Sindhu AS, Severin AJ, Baum TJ. Heterodera glycines utilizes promiscuous spliced leaders and demonstrates a unique preference for a species-specific spliced leader over C. elegans SL1. Sci Rep 2019; 9:1356. [PMID: 30718603 PMCID: PMC6362198 DOI: 10.1038/s41598-018-37857-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/13/2018] [Indexed: 12/30/2022] Open
Abstract
Spliced leader trans-splicing (SLTS) plays a part in the maturation of pre-mRNAs in select species across multiple phyla but is particularly prevalent in Nematoda. The role of spliced leaders (SL) within the cell is unclear and an accurate assessment of SL occurrence within an organism is possible only after extensive sequencing data are available, which is not currently the case for many nematode species. SL discovery is further complicated by an absence of SL sequences from high-throughput sequencing results due to incomplete sequencing of the 5'-ends of transcripts during RNA-seq library preparation, known as 5'-bias. Existing datasets and novel methodology were used to identify both conserved SLs and unique hypervariable SLs within Heterodera glycines, the soybean cyst nematode. In H. glycines, twenty-one distinct SL sequences were found on 2,532 unique H. glycines transcripts. The SL sequences identified on the H. glycines transcripts demonstrated a high level of promiscuity, meaning that some transcripts produced as many as nine different individual SL-transcript combinations. Most uniquely, transcriptome analysis revealed that H. glycines is the first nematode to demonstrate a higher SL trans-splicing rate using a species-specific SL over well-conserved Caenorhabditis elegans SL-like sequences.
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Affiliation(s)
- Stacey N Barnes
- Plant Pathology & Microbiology Department, Iowa State University, Ames, IA, 50011, USA
| | - Rick E Masonbrink
- Office of Biotechnology, Genome Informatics Facility, Iowa State University, Ames, IA, 50011, USA
| | - Thomas R Maier
- Plant Pathology & Microbiology Department, Iowa State University, Ames, IA, 50011, USA
| | - Arun Seetharam
- Office of Biotechnology, Genome Informatics Facility, Iowa State University, Ames, IA, 50011, USA
| | | | - Andrew J Severin
- Office of Biotechnology, Genome Informatics Facility, Iowa State University, Ames, IA, 50011, USA
| | - Thomas J Baum
- Plant Pathology & Microbiology Department, Iowa State University, Ames, IA, 50011, USA.
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29
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Li WV, Li JJ. Modeling and analysis of RNA-seq data: a review from a statistical perspective. QUANTITATIVE BIOLOGY 2018; 6:195-209. [PMID: 31456901 PMCID: PMC6711375 DOI: 10.1007/s40484-018-0144-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/23/2018] [Accepted: 03/29/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Since the invention of next-generation RNA sequencing (RNA-seq) technologies, they have become a powerful tool to study the presence and quantity of RNA molecules in biological samples and have revolutionized transcriptomic studies. The analysis of RNA-seq data at four different levels (samples, genes, transcripts, and exons) involve multiple statistical and computational questions, some of which remain challenging up to date. RESULTS We review RNA-seq analysis tools at the sample, gene, transcript, and exon levels from a statistical perspective. We also highlight the biological and statistical questions of most practical considerations. CONCLUSIONS The development of statistical and computational methods for analyzing RNA-seq data has made significant advances in the past decade. However, methods developed to answer the same biological question often rely on diverse statistical models and exhibit different performance under different scenarios. This review discusses and compares multiple commonly used statistical models regarding their assumptions, in the hope of helping users select appropriate methods as needed, as well as assisting developers for future method development.
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Affiliation(s)
- Wei Vivian Li
- Department of Statistics, University of California, Los Angeles, Los Angeles, CA 90095-1554, USA
| | - Jingyi Jessica Li
- Department of Statistics, University of California, Los Angeles, Los Angeles, CA 90095-1554, USA
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095-088, USA
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30
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Yague-Sanz C, Hermand D. SL-quant: a fast and flexible pipeline to quantify spliced leader trans-splicing events from RNA-seq data. Gigascience 2018; 7:5052207. [PMID: 30010768 PMCID: PMC6055573 DOI: 10.1093/gigascience/giy084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/04/2018] [Accepted: 07/01/2018] [Indexed: 11/13/2022] Open
Abstract
Background The spliceosomal transfer of a short spliced leader (SL) RNA to an independent pre-mRNA molecule is called SL trans-splicing and is widespread in the nematode Caenorhabditis elegans. While RNA-sequencing (RNA-seq) data contain information on such events, properly documented methods to extract them are lacking. Findings To address this, we developed SL-quant, a fast and flexible pipeline that adapts to paired-end and single-end RNA-seq data and accurately quantifies SL trans-splicing events. It is designed to work downstream of read mapping and uses the reads left unmapped as primary input. Briefly, the SL sequences are identified with high specificity and are trimmed from the input reads, which are then remapped on the reference genome and quantified at the nucleotide position level (SL trans-splice sites) or at the gene level. Conclusions SL-quant completes within 10 minutes on a basic desktop computer for typical C. elegans RNA-seq datasets and can be applied to other species as well. Validating the method, the SL trans-splice sites identified display the expected consensus sequence, and the results of the gene-level quantification are predictive of the gene position within operons. We also compared SL-quant to a recently published SL-containing read identification strategy that was found to be more sensitive but less specific than SL-quant. Both methods are implemented as a bash script available under the MIT license [1]. Full instructions for its installation, usage, and adaptation to other organisms are provided.
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Affiliation(s)
- Carlo Yague-Sanz
- URPhyM-GEMO, The University of Namur (UNamur), 61 rue de Bruxelles, 5000 Namur, Belgium
| | - Damien Hermand
- URPhyM-GEMO, The University of Namur (UNamur), 61 rue de Bruxelles, 5000 Namur, Belgium
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