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Bakhtiar D, Vondraskova K, Pengelly RJ, Chivers M, Kralovicova J, Vorechovsky I. Exonic splicing code and coordination of divalent metals in proteins. Nucleic Acids Res 2024; 52:1090-1106. [PMID: 38055834 PMCID: PMC10853796 DOI: 10.1093/nar/gkad1161] [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: 06/16/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 12/08/2023] Open
Abstract
Exonic sequences contain both protein-coding and RNA splicing information but the interplay of the protein and splicing code is complex and poorly understood. Here, we have studied traditional and auxiliary splicing codes of human exons that encode residues coordinating two essential divalent metals at the opposite ends of the Irving-Williams series, a universal order of relative stabilities of metal-organic complexes. We show that exons encoding Zn2+-coordinating amino acids are supported much less by the auxiliary splicing motifs than exons coordinating Ca2+. The handicap of the former is compensated by stronger splice sites and uridine-richer polypyrimidine tracts, except for position -3 relative to 3' splice junctions. However, both Ca2+ and Zn2+ exons exhibit close-to-constitutive splicing in multiple tissues, consistent with their critical importance for metalloprotein function and a relatively small fraction of expendable, alternatively spliced exons. These results indicate that constraints imposed by metal coordination spheres on RNA splicing have been efficiently overcome by the plasticity of exon-intron architecture to ensure adequate metalloprotein expression.
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Affiliation(s)
- Dara Bakhtiar
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Katarina Vondraskova
- Slovak Academy of Sciences, Centre of Biosciences, 840 05 Bratislava, Slovak Republic
| | - Reuben J Pengelly
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Martin Chivers
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
- Slovak Academy of Sciences, Centre of Biosciences, 840 05 Bratislava, Slovak Republic
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
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2
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Borovská I, Vořechovský I, Královičová J. Alu RNA fold links splicing with signal recognition particle proteins. Nucleic Acids Res 2023; 51:8199-8216. [PMID: 37309897 PMCID: PMC10450188 DOI: 10.1093/nar/gkad500] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/23/2023] [Accepted: 05/31/2023] [Indexed: 06/14/2023] Open
Abstract
Transcriptomic diversity in primates was considerably expanded by exonizations of intronic Alu elements. To better understand their cellular mechanisms we have used structure-based mutagenesis coupled with functional and proteomic assays to study the impact of successive primate mutations and their combinations on inclusion of a sense-oriented AluJ exon in the human F8 gene. We show that the splicing outcome was better predicted by consecutive RNA conformation changes than by computationally derived splicing regulatory motifs. We also demonstrate an involvement of SRP9/14 (signal recognition particle) heterodimer in splicing regulation of Alu-derived exons. Nucleotide substitutions that accumulated during primate evolution relaxed the conserved left-arm AluJ structure including helix H1 and reduced the capacity of SRP9/14 to stabilize the closed Alu conformation. RNA secondary structure-constrained mutations that promoted open Y-shaped conformations of the Alu made the Alu exon inclusion reliant on DHX9. Finally, we identified additional SRP9/14 sensitive Alu exons and predicted their functional roles in the cell. Together, these results provide unique insights into architectural elements required for sense Alu exonization, identify conserved pre-mRNA structures involved in exon selection and point to a possible chaperone activity of SRP9/14 outside the mammalian signal recognition particle.
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Affiliation(s)
- Ivana Borovská
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava 840 05, Slovak Republic
| | - Igor Vořechovský
- Faculty of Medicine, University of Southampton, HDH, MP808, Southampton SO16 6YD, United Kingdom
| | - Jana Královičová
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava 840 05, Slovak Republic
- Institute of Zoology, Slovak Academy of Sciences, Bratislava 845 06, Slovak Republic
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3
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Guerra M, Meola L, Lattante S, Conte A, Sabatelli M, Sette C, Bernardini C. Characterization of SOD1-DT, a Divergent Long Non-Coding RNA in the Locus of the SOD1 Human Gene. Cells 2023; 12:2058. [PMID: 37626868 PMCID: PMC10453398 DOI: 10.3390/cells12162058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/03/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
Researchers studying Amyotrophic Lateral Sclerosis (ALS) have made significant efforts to find a unique mechanism to explain the etiopathology of the different forms of the disease. However, despite several mutations associated with ALS having been discovered in recent years, the link between the mutated genes and its onset has not yet been fully elucidated. Among the genes associated with ALS, superoxide dismutase 1 (SOD1) was the first to be identified, but its role in the etiopathogenesis of the disease is still unclear. In recent years, research has been focused on the non-coding part of the genome to fully understand the mechanisms underlying gene regulation. Non-coding RNAs are conserved molecules and are not usually translated in protein. A total of 98% of the human genome is composed of non-protein coding sequences with roles in the transcriptional and post-transcriptional regulation of gene expression. In this study, we characterized a divergent nuclear lncRNA (SOD1-DT) transcribed in the antisense direction from the 5' region of the SOD1 coding gene in both the SH-SY5Y cell line and fibroblasts derived from ALS patients. Interestingly, this lncRNA seems to regulate gene expression, since its inhibition leads to the upregulation of surrounding genes including SOD1. SOD1-DT represents a very complex molecule, displaying allelic and transcriptional variability concerning transposable elements (TEs) included in its sequence, widening the scenario of gene expression regulation in ALS disease.
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Affiliation(s)
- Marika Guerra
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, 00168 Rome, Italy; (L.M.); (C.S.)
- GSTeP-Organoids Research Core Facility, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Lucia Meola
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, 00168 Rome, Italy; (L.M.); (C.S.)
| | - Serena Lattante
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy;
| | - Amelia Conte
- Adult NEMO Clinical Center, Unit of Neurology, Department of Aging, Neurological, Orthopedic and Head-Neck Sciences, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.C.); (M.S.)
| | - Mario Sabatelli
- Adult NEMO Clinical Center, Unit of Neurology, Department of Aging, Neurological, Orthopedic and Head-Neck Sciences, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (A.C.); (M.S.)
- Section of Neurology, Department of Neuroscience, Faculty of Medicine and Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, 00168 Rome, Italy; (L.M.); (C.S.)
- GSTeP-Organoids Research Core Facility, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Camilla Bernardini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, 00168 Rome, Italy; (L.M.); (C.S.)
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Girardini KN, Olthof AM, Kanadia RN. Introns: the "dark matter" of the eukaryotic genome. Front Genet 2023; 14:1150212. [PMID: 37260773 PMCID: PMC10228655 DOI: 10.3389/fgene.2023.1150212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/02/2023] Open
Abstract
The emergence of introns was a significant evolutionary leap that is a major distinguishing feature between prokaryotic and eukaryotic genomes. While historically introns were regarded merely as the sequences that are removed to produce spliced transcripts encoding functional products, increasingly data suggests that introns play important roles in the regulation of gene expression. Here, we use an intron-centric lens to review the role of introns in eukaryotic gene expression. First, we focus on intron architecture and how it may influence mechanisms of splicing. Second, we focus on the implications of spliceosomal snRNAs and their variants on intron splicing. Finally, we discuss how the presence of introns and the need to splice them influences transcription regulation. Despite the abundance of introns in the eukaryotic genome and their emerging role regulating gene expression, a lot remains unexplored. Therefore, here we refer to introns as the "dark matter" of the eukaryotic genome and discuss some of the outstanding questions in the field.
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Affiliation(s)
- Kaitlin N. Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
| | - Anouk M. Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Rahul N. Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, United States
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5
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Merlotti A, Sadacca B, Arribas YA, Ngoma M, Burbage M, Goudot C, Houy A, Rocañín-Arjó A, Lalanne A, Seguin-Givelet A, Lefevre M, Heurtebise-Chrétien S, Baudon B, Oliveira G, Loew D, Carrascal M, Wu CJ, Lantz O, Stern MH, Girard N, Waterfall JJ, Amigorena S. Noncanonical splicing junctions between exons and transposable elements represent a source of immunogenic recurrent neo-antigens in patients with lung cancer. Sci Immunol 2023; 8:eabm6359. [PMID: 36735774 DOI: 10.1126/sciimmunol.abm6359] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/12/2023] [Indexed: 02/05/2023]
Abstract
Although most characterized tumor antigens are encoded by canonical transcripts (such as differentiation or tumor-testis antigens) or mutations (both driver and passenger mutations), recent results have shown that noncanonical transcripts including long noncoding RNAs and transposable elements (TEs) can also encode tumor-specific neo-antigens. Here, we investigate the presentation and immunogenicity of tumor antigens derived from noncanonical mRNA splicing events between coding exons and TEs. Comparing human non-small cell lung cancer (NSCLC) and diverse healthy tissues, we identified a subset of splicing junctions that is both tumor specific and shared across patients. We used HLA-I peptidomics to identify peptides encoded by tumor-specific junctions in primary NSCLC samples and lung tumor cell lines. Recurrent junction-encoded peptides were immunogenic in vitro, and CD8+ T cells specific for junction-encoded epitopes were present in tumors and tumor-draining lymph nodes from patients with NSCLC. We conclude that noncanonical splicing junctions between exons and TEs represent a source of recurrent, immunogenic tumor-specific antigens in patients with NSCLC.
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Affiliation(s)
- Antonela Merlotti
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
| | - Benjamin Sadacca
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
- INSERM U830, PSL Research University, Institute Curie Research Center, Paris, France
- Department of Translational Research, PSL Research University, Institut Curie Research Center, Paris, France
| | - Yago A Arribas
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
| | - Mercia Ngoma
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
| | - Marianne Burbage
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
| | - Christel Goudot
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
| | - Alexandre Houy
- INSERM U830, PSL Research University, Institute Curie Research Center, Paris, France
| | - Ares Rocañín-Arjó
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
| | - Ana Lalanne
- Institut Curie, Laboratory of Clinical immunology, 75005 Paris, France
- Institut Curie, CIC-BT1428, 75005 Paris, France
| | - Agathe Seguin-Givelet
- Thoracic Surgery Department, Curie-Montsouris Thorax Institute - Institut Mutualiste Montsouris, Paris, France
- Paris 13 University, Sorbonne Paris Cité, Faculty of Medicine SMBH, Bobigny, France
| | - Marine Lefevre
- Department of Pathology, Institute Mutualiste Montsouris, Paris, France
| | | | - Blandine Baudon
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
| | - Giacomo Oliveira
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Damarys Loew
- Institut Curie, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, PSL Research University, Paris cedex 05, France
| | - Montserrat Carrascal
- Biological and Environmental Proteomics, Institut d'Investigacions Biomèdiques de Barcelona-CSIC, IDIBAPS, Roselló 161, 6a planta, 08036 Barcelona, Spain
| | - Catherine J Wu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Olivier Lantz
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
- Institut Curie, Laboratory of Clinical immunology, 75005 Paris, France
- Institut Curie, CIC-BT1428, 75005 Paris, France
| | - Marc-Henri Stern
- INSERM U830, PSL Research University, Institute Curie Research Center, Paris, France
| | - Nicolas Girard
- Thoracic Surgery Department, Curie-Montsouris Thorax Institute - Institut Mutualiste Montsouris, Paris, France
| | - Joshua J Waterfall
- INSERM U830, PSL Research University, Institute Curie Research Center, Paris, France
- Department of Translational Research, PSL Research University, Institut Curie Research Center, Paris, France
| | - Sebastian Amigorena
- Institut Curie, Université Paris Sciences et Lettres, INSERM U932, 75005 Paris, France
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6
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D A, Y L, R S, H D, E B, Rm W, I V, L C, N.J D. Background splicing as a predictor of aberrant splicing in genetic disease. RNA Biol 2022; 19:256-265. [PMID: 35188075 PMCID: PMC8865296 DOI: 10.1080/15476286.2021.2024031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mutations of splice sites, auxiliary splicing elements and the splicing machinery cause a wide range of genetic disease. Here we report that many of the complex effects of splicing mutations can be predicted from background splicing information, with emphasis on BRCA1, BRCA2 and DMD. Background splicing arises from very low level splicing between rarely used background splice sites and from low-level exon skipping between intron splice sites. We show how this information can be downloaded from the Snaptron database of spliced RNA, which we then compared with databases of human splice site mutations. We report that inactivating mutations of intron splice sites typically caused the non-mutated partner splice site to splice to a known background splice site in over 90% of cases and to the strongest background splice site in the large majority of cases. Consequently, background splicing information can usefully predict the effects of splice site mutations, which include cryptic splice activation and single or multiple exon skipping. In addition, de novo splice sites and splice sites involved in pseudoexon formation, recursive splicing and aberrant splicing in cancer show a 90% match to background splice sites, so establishing that the enhancement of background splicing causes a wide range of splicing aberrations. We also discuss how background splicing information can identify cryptic splice sites that might be usefully targeted by antisense oligonucleotides (ASOs) and how it might indicate possible multiple exon skipping side effects of ASOs designed to induce single exon skipping.
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Affiliation(s)
- Alexieva D
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
| | - Long Y
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
| | - Sarkar R
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
| | - Dhayan H
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
| | - Bruet E
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
| | - Winston Rm
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
| | - Vorechovsky I
- Faculty of Medicine, University of Southampton, Southampton, UK
| | - Castellano L
- Department of Surgery and Cancer, Imperial College London, Imperial Centre for Translational and Experimental Medicine (Ictem), London, UK
- School of Life Sciences, University of Sussex, Falmer, UK
| | - Dibb N.J
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
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7
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Dynamic Variations of 3'UTR Length Reprogram the mRNA Regulatory Landscape. Biomedicines 2021; 9:biomedicines9111560. [PMID: 34829789 PMCID: PMC8615635 DOI: 10.3390/biomedicines9111560] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/10/2021] [Accepted: 10/15/2021] [Indexed: 12/16/2022] Open
Abstract
This paper concerns 3′-untranslated regions (3′UTRs) of mRNAs, which are non-coding regulatory platforms that control stability, fate and the correct spatiotemporal translation of mRNAs. Many mRNAs have polymorphic 3′UTR regions. Controlling 3′UTR length and sequence facilitates the regulation of the accessibility of functional effectors (RNA binding proteins, miRNAs or other ncRNAs) to 3′UTR functional boxes and motifs and the establishment of different regulatory landscapes for mRNA function. In this context, shortening of 3′UTRs would loosen miRNA or protein-based mechanisms of mRNA degradation, while 3′UTR lengthening would strengthen accessibility to these effectors. Alterations in the mechanisms regulating 3′UTR length would result in widespread deregulation of gene expression that could eventually lead to diseases likely linked to the loss (or acquisition) of specific miRNA binding sites. Here, we will review the mechanisms that control 3′UTR length dynamics and their alterations in human disorders. We will discuss, from a mechanistic point of view centered on the molecular machineries involved, the generation of 3′UTR variability by the use of alternative polyadenylation and cleavage sites, of mutually exclusive terminal alternative exons (exon skipping) as well as by the process of exonization of Alu cassettes to generate new 3′UTRs with differential functional features.
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8
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Královičová J, Borovská I, Pengelly R, Lee E, Abaffy P, Šindelka R, Grutzner F, Vořechovský I. Restriction of an intron size en route to endothermy. Nucleic Acids Res 2021; 49:2460-2487. [PMID: 33550394 PMCID: PMC7969005 DOI: 10.1093/nar/gkab046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 11/15/2022] Open
Abstract
Ca2+-insensitive and -sensitive E1 subunits of the 2-oxoglutarate dehydrogenase complex (OGDHC) regulate tissue-specific NADH and ATP supply by mutually exclusive OGDH exons 4a and 4b. Here we show that their splicing is enforced by distant lariat branch points (dBPs) located near the 5' splice site of the intervening intron. dBPs restrict the intron length and prevent transposon insertions, which can introduce or eliminate dBP competitors. The size restriction was imposed by a single dominant dBP in anamniotes that expanded into a conserved constellation of four dBP adenines in amniotes. The amniote clusters exhibit taxon-specific usage of individual dBPs, reflecting accessibility of their extended motifs within a stable RNA hairpin rather than U2 snRNA:dBP base-pairing. The dBP expansion took place in early terrestrial species and was followed by a uridine enrichment of large downstream polypyrimidine tracts in mammals. The dBP-protected megatracts permit reciprocal regulation of exon 4a and 4b by uridine-binding proteins, including TIA-1/TIAR and PUF60, which promote U1 and U2 snRNP recruitment to the 5' splice site and BP, respectively, but do not significantly alter the relative dBP usage. We further show that codons for residues critically contributing to protein binding sites for Ca2+ and other divalent metals confer the exon inclusion order that mirrors the Irving-Williams affinity series, linking the evolution of auxiliary splicing motifs in exons to metallome constraints. Finally, we hypothesize that the dBP-driven selection for Ca2+-dependent ATP provision by E1 facilitated evolution of endothermy by optimizing the aerobic scope in target tissues.
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Affiliation(s)
- Jana Královičová
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Ivana Borovská
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Reuben Pengelly
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
| | - Eunice Lee
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Pavel Abaffy
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Radek Šindelka
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Frank Grutzner
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Igor Vořechovský
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
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