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Subramani PG, Fraszczak J, Helness A, Estall JL, Möröy T, Di Noia JM. Conserved role of hnRNPL in alternative splicing of epigenetic modifiers enables B cell activation. EMBO Rep 2024; 25:2662-2697. [PMID: 38744970 PMCID: PMC11169469 DOI: 10.1038/s44319-024-00152-3] [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: 10/05/2023] [Revised: 04/15/2024] [Accepted: 04/24/2024] [Indexed: 05/16/2024] Open
Abstract
The multifunctional RNA-binding protein hnRNPL is implicated in antibody class switching but its broader function in B cells is unknown. Here, we show that hnRNPL is essential for B cell activation, germinal center formation, and antibody responses. Upon activation, hnRNPL-deficient B cells show proliferation defects and increased apoptosis. Comparative analysis of RNA-seq data from activated B cells and another eight hnRNPL-depleted cell types reveals common effects on MYC and E2F transcriptional programs required for proliferation. Notably, while individual gene expression changes are cell type specific, several alternative splicing events affecting histone modifiers like KDM6A and SIRT1, are conserved across cell types. Moreover, hnRNPL-deficient B cells show global changes in H3K27me3 and H3K9ac. Epigenetic dysregulation after hnRNPL loss could underlie differential gene expression and upregulation of lncRNAs, and explain common and cell type-specific phenotypes, such as dysfunctional mitochondria and ROS overproduction in mouse B cells. Thus, hnRNPL is essential for the resting-to-activated B cell transition by regulating transcriptional programs and metabolism, at least in part through the alternative splicing of several histone modifiers.
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Affiliation(s)
- Poorani Ganesh Subramani
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada
| | - Jennifer Fraszczak
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Anne Helness
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
| | - Jennifer L Estall
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada
- Molecular Biology Programs, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada
- Department of Medicine, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada
| | - Tarik Möröy
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada
- Molecular Biology Programs, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, 2900 Boul Edouard-Montpetit, Montréal, QC, H3T 1J4, Canada
| | - Javier M Di Noia
- Institut de Recherches Cliniques de Montréal, 110 avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada.
- Department of Medicine, Division of Experimental Medicine, McGill University, 1001 Boulevard Decarie, Montreal, QC, H4A 3J1, Canada.
- Molecular Biology Programs, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada.
- Department of Medicine, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC, H3C 3J7, Canada.
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, 2900 Boul Edouard-Montpetit, Montréal, QC, H3T 1J4, Canada.
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2
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Shamnas v M, Singh A, Kumar A, Mishra GP, Sinha SK. Exitrons: offering new roles to retained introns-the novel regulators of protein diversity and utility. AOB PLANTS 2024; 16:plae014. [PMID: 38566894 PMCID: PMC10985678 DOI: 10.1093/aobpla/plae014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024]
Abstract
Exitrons are exonic introns. This subclass of intron retention alternative splicing does not contain a Pre-Terminating stop Codon. Therefore, when retained, they are always a part of a protein. Intron retention is a frequent phenomenon predominantly found in plants, which results in either the degradation of the transcripts or can serve as a stable intermediate to be processed upon induction by specific signals or the cell status. Interestingly, exitrons have coding ability and may confer additional attributes to the proteins that retain them. Therefore, exitron-containing and exitron-spliced isoforms will be a driving force for creating protein diversity in the proteome of an organism. This review establishes a basic understanding of exitron, discussing its genesis, key features, identification methods and functions. We also try to depict its other potential roles. The present review also aims to provide a fundamental background to those who found such exitronic sequences in their gene(s) and to speculate the future course of studies.
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Affiliation(s)
- Muhammed Shamnas v
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
| | - Akanksha Singh
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
- Department of Botany and Plant Pathology, Lilly Hall of Life Sciences, Purdue University, West Lafayette 47906, Indiana, USA
| | - Anuj Kumar
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
| | - Gyan Prakash Mishra
- Division of Genetics, ICAR-Indian Agricultural Research Institute, Pusa Campus, New Delhi 110012, India
| | - Subodh Kumar Sinha
- ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India
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3
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Vorobeva MA, Skvortsov DA, Pervouchine DD. Cooperation and Competition of RNA Secondary Structure and RNA-Protein Interactions in the Regulation of Alternative Splicing. Acta Naturae 2023; 15:23-31. [PMID: 38234601 PMCID: PMC10790352 DOI: 10.32607/actanaturae.26826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 10/31/2023] [Indexed: 01/19/2024] Open
Abstract
The regulation of alternative splicing in eukaryotic cells is carried out through the coordinated action of a large number of factors, including RNA-binding proteins and RNA structure. The RNA structure influences alternative splicing by blocking cis-regulatory elements, or bringing them closer or farther apart. In combination with RNA-binding proteins, it generates transcript conformations that help to achieve the necessary splicing outcome. However, the binding of regulatory proteins depends on RNA structure and, vice versa, the formation of RNA structure depends on the interaction with regulators. Therefore, RNA structure and RNA-binding proteins are inseparable components of common regulatory mechanisms. This review highlights examples of alternative splicing regulation by RNA-binding proteins, the regulation through local and long-range RNA structures, as well as how these elements work together, cooperate, and compete.
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Affiliation(s)
- M. A. Vorobeva
- M.V. Lomonosov Moscow State University, Moscow, 119192 Russian Federation
| | - D. A. Skvortsov
- M.V. Lomonosov Moscow State University, Moscow, 119192 Russian Federation
| | - D. D. Pervouchine
- Skolkovo Institute of Science and Technology, Moscow, 121205 Russian Federation
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4
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Choquet K, Baxter-Koenigs AR, Dülk SL, Smalec BM, Rouskin S, Churchman LS. Pre-mRNA splicing order is predetermined and maintains splicing fidelity across multi-intronic transcripts. Nat Struct Mol Biol 2023; 30:1064-1076. [PMID: 37443198 PMCID: PMC10653200 DOI: 10.1038/s41594-023-01035-2] [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: 07/19/2022] [Accepted: 06/13/2023] [Indexed: 07/15/2023]
Abstract
Combinatorially, intron excision within a given nascent transcript could proceed down any of thousands of paths, each of which would expose different dynamic landscapes of cis-elements and contribute to alternative splicing. In this study, we found that post-transcriptional multi-intron splicing order in human cells is largely predetermined, with most genes spliced in one or a few predominant orders. Strikingly, these orders were conserved across cell types and stages of motor neuron differentiation. Introns flanking alternatively spliced exons were frequently excised last, after their neighboring introns. Perturbations to the spliceosomal U2 snRNA altered the preferred splicing order of many genes, and these alterations were associated with the retention of other introns in the same transcript. In one gene, early removal of specific introns was sufficient to induce delayed excision of three proximal introns, and this delay was caused by two distinct cis-regulatory mechanisms. Together, our results demonstrate that multi-intron splicing order in human cells is predetermined, is influenced by a component of the spliceosome and ensures splicing fidelity across long pre-mRNAs.
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Affiliation(s)
- Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | | | - Sarah-Luisa Dülk
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Brendan M Smalec
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Silvi Rouskin
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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5
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Haque N, Will A, Cook AG, Hogg JR. A network of DZF proteins controls alternative splicing regulation and fidelity. Nucleic Acids Res 2023; 51:6411-6429. [PMID: 37144502 PMCID: PMC10325889 DOI: 10.1093/nar/gkad351] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/12/2023] [Accepted: 05/03/2023] [Indexed: 05/06/2023] Open
Abstract
Proteins containing DZF (domain associated with zinc fingers) modules play important roles throughout gene expression, from transcription to translation. Derived from nucleotidyltransferases but lacking catalytic residues, DZF domains serve as heterodimerization surfaces between DZF protein pairs. Three DZF proteins are widely expressed in mammalian tissues, ILF2, ILF3 and ZFR, which form mutually exclusive ILF2-ILF3 and ILF2-ZFR heterodimers. Using eCLIP-Seq, we find that ZFR binds across broad intronic regions to regulate the alternative splicing of cassette and mutually exclusive exons. ZFR preferentially binds dsRNA in vitro and is enriched on introns containing conserved dsRNA elements in cells. Many splicing events are similarly altered upon depletion of any of the three DZF proteins; however, we also identify independent and opposing roles for ZFR and ILF3 in alternative splicing regulation. Along with widespread involvement in cassette exon splicing, the DZF proteins control the fidelity and regulation of over a dozen highly validated mutually exclusive splicing events. Our findings indicate that the DZF proteins form a complex regulatory network that leverages dsRNA binding by ILF3 and ZFR to modulate splicing regulation and fidelity.
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Affiliation(s)
- Nazmul Haque
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD20892, USA
| | - Alexander Will
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Atlanta G Cook
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - J Robert Hogg
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD20892, USA
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6
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Martinez-Gomez L, Cerdán-Vélez D, Abascal F, Tress ML. Origins and Evolution of Human Tandem Duplicated Exon Substitution Events. Genome Biol Evol 2022; 14:6809199. [PMID: 36346145 PMCID: PMC9741552 DOI: 10.1093/gbe/evac162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/25/2022] [Accepted: 10/29/2022] [Indexed: 11/10/2022] Open
Abstract
The mutually exclusive splicing of tandem duplicated exons produces protein isoforms that are identical save for a homologous region that allows for the fine tuning of protein function. Tandem duplicated exon substitution events are rare, yet highly important alternative splicing events. Most events are ancient, their isoforms are highly expressed, and they have significantly more pathogenic mutations than other splice events. Here, we analyzed the physicochemical properties and functional roles of the homologous polypeptide regions produced by the 236 tandem duplicated exon substitutions annotated in the human gene set. We find that the most important structural and functional residues in these homologous regions are maintained, and that most changes are conservative rather than drastic. Three quarters of the isoforms produced from tandem duplicated exon substitution events are tissue-specific, particularly in nervous and cardiac tissues, and tandem duplicated exon substitution events are enriched in functional terms related to structures in the brain and skeletal muscle. We find considerable evidence for the convergent evolution of tandem duplicated exon substitution events in vertebrates, arthropods, and nematodes. Twelve human gene families have orthologues with tandem duplicated exon substitution events in both Drosophila melanogaster and Caenorhabditis elegans. Six of these gene families are ion transporters, suggesting that tandem exon duplication in genes that control the flow of ions into the cell has an adaptive benefit. The ancient origins, the strong indications of tissue-specific functions, and the evidence of convergent evolution suggest that these events may have played important roles in the evolution of animal tissues and organs.
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Affiliation(s)
- Laura Martinez-Gomez
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), C. Melchor Fernandez Almagro, 3, 28029 Madrid, Spain
| | - Daniel Cerdán-Vélez
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), C. Melchor Fernandez Almagro, 3, 28029 Madrid, Spain
| | - Federico Abascal
- Somatic Evolution Group, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
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7
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Shilo A, Pegoraro G, Misteli T. HiFENS: high-throughput FISH detection of endogenous pre-mRNA splicing isoforms. Nucleic Acids Res 2022; 50:e130. [PMID: 36243969 PMCID: PMC9825148 DOI: 10.1093/nar/gkac869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/01/2022] [Accepted: 09/27/2022] [Indexed: 01/29/2023] Open
Abstract
Splicing factors play an essential role in regulation of alternative pre-mRNA splicing. While much progress has been made in delineating the mechanisms of the splicing machinery, the identity of signal transduction pathways and upstream factors that regulate splicing factor activity is largely unknown. A major challenge in the discovery of upstream regulatory factors of pre-mRNA splicing is the scarcity of functional genomics screening methods to monitor splicing outcomes of endogenous genes. Here, we have developed HiFENS (high throughput FISH detection of endogenous splicing isoforms), a high-throughput imaging assay based on hybridization chain reaction (HCR) and used HiFENS to screen for cellular factors that regulate alternative splicing of endogenous genes. We demonstrate optimized detection with high specificity of endogenous splicing isoforms and multiplexing of probes for accurate detection of splicing outcomes with single cell resolution. As proof-of-principle, we perform an RNAi screen of 702 human kinases and identify potential candidate upstream splicing regulators of the FGFR2 gene. HiFENS should be a useful tool for the unbiased delineation of cellular pathways involved in alternative splicing regulation.
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Affiliation(s)
- Asaf Shilo
- Cell Biology of Genomes, Center for Cancer Research (CCR), National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Gianluca Pegoraro
- High-Throughput Imaging Facility (HiTIF), Center for Cancer Research (CCR), National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Tom Misteli
- To whom correspondence should be addressed. Tel: +1 240 670 6669; Fax: +1 240 670 6670;
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8
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Wright CJ, Smith CWJ, Jiggins CD. Alternative splicing as a source of phenotypic diversity. Nat Rev Genet 2022; 23:697-710. [PMID: 35821097 DOI: 10.1038/s41576-022-00514-4] [Citation(s) in RCA: 102] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2022] [Indexed: 12/27/2022]
Abstract
A major goal of evolutionary genetics is to understand the genetic processes that give rise to phenotypic diversity in multicellular organisms. Alternative splicing generates multiple transcripts from a single gene, enriching the diversity of proteins and phenotypic traits. It is well established that alternative splicing contributes to key innovations over long evolutionary timescales, such as brain development in bilaterians. However, recent developments in long-read sequencing and the generation of high-quality genome assemblies for diverse organisms has facilitated comparisons of splicing profiles between closely related species, providing insights into how alternative splicing evolves over shorter timescales. Although most splicing variants are probably non-functional, alternative splicing is nonetheless emerging as a dynamic, evolutionarily labile process that can facilitate adaptation and contribute to species divergence.
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Affiliation(s)
- Charlotte J Wright
- Tree of Life, Wellcome Sanger Institute, Cambridge, UK. .,Department of Zoology, University of Cambridge, Cambridge, UK.
| | | | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge, UK.
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9
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Hou S, Li G, Xu B, Dong H, Zhang S, Fu Y, Shi J, Li L, Fu J, Shi F, Meng Y, Jin Y. Trans-splicing facilitated by RNA pairing greatly expands sDscam isoform diversity but not homophilic binding specificity. SCIENCE ADVANCES 2022; 8:eabn9458. [PMID: 35857463 PMCID: PMC9258826 DOI: 10.1126/sciadv.abn9458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 05/21/2022] [Indexed: 06/15/2023]
Abstract
The Down syndrome cell adhesion molecule 1 (Dscam1) gene can generate tens of thousands of isoforms via alternative splicing, which is essential for nervous and immune functions. Chelicerates generate approximately 50 to 100 shortened Dscam (sDscam) isoforms by alternative promoters, similar to mammalian protocadherins. Here, we reveal that trans-splicing markedly increases the repository of sDscamβ isoforms in Tetranychus urticae. Unexpectedly, every variable exon cassette engages in trans-splicing with constant exons from another cluster. Moreover, we provide evidence that competing RNA pairing not only governs alternative cis-splicing but also facilitates trans-splicing. Trans-spliced sDscam isoforms mediate cell adhesion ability but exhibit the same homophilic binding specificity as their cis-spliced counterparts. Thus, we reveal a single sDscam locus that generates diverse adhesion molecules through cis- and trans-splicing coupled with alternative promoters. These findings expand understanding of the mechanism underlying molecular diversity and have implications for the molecular control of neuronal and/or immune specificity.
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Affiliation(s)
- Shouqing Hou
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Guo Li
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Jiayan Fu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Yijun Meng
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang ZJ310018, P. R. China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
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10
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Zhi X, Pu L, Wu B, Cui Y, Yu C, Dong Y, Li D, Cai C. Identification of two aberrant transcripts by RNA sequencing for a novel variant c.3354 + 5 G > A of MED12 in a Chinese girl with non-syndromic intellectual disability. Clin Chim Acta 2022; 532:137-144. [PMID: 35690084 DOI: 10.1016/j.cca.2022.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/27/2022] [Accepted: 05/27/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Missense variants in MED12 are associated with MED12-related disorders. We aimed to clarify the molecular level changes and underlying pathogenic mechanism of a female patient in our study. METHODS We reported a Chinese girl with clinical characteristics similar to MED12-related disorders. Trio whole exome sequencing (WES) was performed to identify related pathogenic variant(s) and RNA sequencing (RNA-seq) was subsequently applied to evaluate the effect of identified variant(s) on mRNA splicing. Moreover, X-chromosome inactivation (XCI) assay based on AR and RP2 was performed to reveal the XCI pattern of the female patient. RESULTS The proband manifested mainly as mental retardation and language impairment. Trio WES revealed a novel heterozygous variant c.3354 + 5 G > A in intron 23 of MED12. RNA-seq identified two aberrant transcripts. XCI assay on AR revealed a homozygous result, while XCI based on RP2 showed random pattern in peripheral blood. CONCLUSION In conclusion, we identified a novel variant c.3354 + 5 G > A by WES combined with RNA-seq, which extends the spectrum of MED12 variants and provide a basis for further genetic counseling. According to the result of two aberrant transcripts by RNA-seq, we speculate that our patient's milder clinical feature may be the consequence of multiple different transcripts.
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Affiliation(s)
- Xiufang Zhi
- Graduate College of Tianjin Medical University, No. 22 Qixiangtai Road, Heping District, Tianjin 300070, China; Tianjin Children's Hospital (Children's Hospital of Tianjin University), No. 238 Longyan Road, Beichen District, Tianjin 300134, China
| | - Linjie Pu
- Graduate College of Tianjin Medical University, No. 22 Qixiangtai Road, Heping District, Tianjin 300070, China; Tianjin Children's Hospital (Children's Hospital of Tianjin University), No. 238 Longyan Road, Beichen District, Tianjin 300134, China
| | - Bo Wu
- Tianjin Children's Hospital (Children's Hospital of Tianjin University), No. 238 Longyan Road, Beichen District, Tianjin 300134, China; Department of Neurology, Tianjin Children's Hospital, No. 238 Longyan Road, eichen District, Tianjin 300134, China
| | - Yaqiong Cui
- Tianjin Children's Hospital (Children's Hospital of Tianjin University), No. 238 Longyan Road, Beichen District, Tianjin 300134, China; Tianjin Pediatric Research Institute, No. 238 Longyan Road, Beichen District, Tianjin 300134, China; Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, No. 238 Longyan Road, Beichen District, Tianjin 300134, China
| | - Changshun Yu
- Tianjin Kingmed Center for Clinical Laboratory Co. Ltd, Haitai Huake 5th Rd, Huayuan Industrial Park, High Tech Zone, Xiqing District, Tianjin 300392, China
| | - Yan Dong
- Graduate College of Tianjin Medical University, No. 22 Qixiangtai Road, Heping District, Tianjin 300070, China; Tianjin Children's Hospital (Children's Hospital of Tianjin University), No. 238 Longyan Road, Beichen District, Tianjin 300134, China
| | - Dong Li
- Tianjin Children's Hospital (Children's Hospital of Tianjin University), No. 238 Longyan Road, Beichen District, Tianjin 300134, China; Department of Neurology, Tianjin Children's Hospital, No. 238 Longyan Road, eichen District, Tianjin 300134, China.
| | - Chunquan Cai
- Tianjin Children's Hospital (Children's Hospital of Tianjin University), No. 238 Longyan Road, Beichen District, Tianjin 300134, China; Tianjin Pediatric Research Institute, No. 238 Longyan Road, Beichen District, Tianjin 300134, China; Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, No. 238 Longyan Road, Beichen District, Tianjin 300134, China.
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11
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Dong H, Xu B, Guo P, Zhang J, Yang X, Li L, Fu Y, Shi J, Zhang S, Zhu Y, Shi Y, Zhou F, Bian L, You W, Shi F, Yang X, Huang J, He H, Jin Y. Hidden RNA pairings counteract the "first-come, first-served" splicing principle to drive stochastic choice in Dscam1 splice variants. SCIENCE ADVANCES 2022; 8:eabm1763. [PMID: 35080968 PMCID: PMC8791459 DOI: 10.1126/sciadv.abm1763] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Drosophila melanogaster Dscam1 encodes 38,016 isoforms via mutually exclusive splicing; however, the regulatory mechanism behind this is not fully understood. Here, we found a set of hidden RNA secondary structures that balance the stochastic choice of Dscam1 splice variants (designated balancer RNA secondary structures). In vivo mutational analyses revealed the dual function of these balancer interactions in driving the stochastic choice of splice variants, through enhancement of the inclusion of distal exon 6s by cooperating with docking site–selector pairing to form a stronger multidomain pre-mRNA structure and through simultaneous repression of the inclusion of proximal exon 6s by antagonizing their docking site–selector pairings. Thus, we provide an elegant molecular model based on competition and cooperation between two sets of docking site–selector and balancer pairings, which counteracts the “first-come, first-served” principle. Our findings provide conceptual and mechanistic insight into the dynamics and functions of long-range RNA secondary structures.
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Affiliation(s)
- Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Pengjuan Guo
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jian Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xi Yang
- Department of Neurosurgery and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yanda Zhu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yang Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Fengyan Zhou
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Lina Bian
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Wendong You
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xiaofeng Yang
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jianhua Huang
- Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Haihuai He
- Department of Neurosurgery and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
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12
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Öther-Gee Pohl S, Myant KB. Alternative RNA splicing in tumour heterogeneity, plasticity and therapy. Dis Model Mech 2022; 15:dmm049233. [PMID: 35014671 PMCID: PMC8764416 DOI: 10.1242/dmm.049233] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alternative splicing is a process by which a single gene is able to encode multiple different protein isoforms. It is regulated by the inclusion or exclusion of introns and exons that are joined in different patterns prior to protein translation, thus enabling transcriptomic and proteomic diversity. It is now widely accepted that alternative splicing is dysregulated across nearly all cancer types. This widespread dysregulation means that nearly all cellular processes are affected - these include processes synonymous with the hallmarks of cancer - evasion of apoptosis, tissue invasion and metastasis, altered cellular metabolism, genome instability and drug resistance. Emerging evidence indicates that the dysregulation of alternative splicing also promotes a permissive environment for increased tumour heterogeneity and cellular plasticity. These are fundamental regulators of a patient's response to therapy. In this Review, we introduce the mechanisms of alternative splicing and the role of aberrant splicing in cancer, with particular focus on newfound evidence of alternative splicing promoting tumour heterogeneity, cellular plasticity and altered metabolism. We discuss recent in vivo models generated to study alternative splicing and the importance of these for understanding complex tumourigenic processes. Finally, we review the effects of alternative splicing on immune evasion, cell death and genome instability, and how targeting these might enhance therapeutic efficacy.
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Affiliation(s)
| | - Kevin B. Myant
- Cancer Research UK Edinburgh Centre, Institute of Genetics of Cancer, The University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
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13
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Ferragut Cardoso AP, Banerjee M, Al-Eryani L, Sayed M, Wilkey DW, Merchant ML, Park JW, States JC. Temporal Modulation of Differential Alternative Splicing in HaCaT Human Keratinocyte Cell Line Chronically Exposed to Arsenic for up to 28 Wk. ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:17011. [PMID: 35072517 PMCID: PMC8785870 DOI: 10.1289/ehp9676] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
BACKGROUND Chronic arsenic exposure via drinking water is associated with an increased risk of developing cancer and noncancer chronic diseases. Pre-mRNAs are often subject to alternative splicing, generating mRNA isoforms encoding functionally distinct protein isoforms. The resulting imbalance in isoform species can result in pathogenic changes in critical signaling pathways. Alternative splicing as a mechanism of arsenic-induced toxicity and carcinogenicity is understudied. OBJECTIVE This study aimed to accurately profile differential alternative splicing events in human keratinocytes induced by chronic arsenic exposure that might play a role in carcinogenesis. METHODS Independent quadruplicate cultures of immortalized human keratinocytes (HaCaT) were maintained continuously for 28 wk with 0 or 100 nM sodium arsenite. RNA-sequencing (RNA-Seq) was performed with poly(A) RNA isolated from cells harvested at 7, 19, and 28 wk with subsequent replicate multivariate analysis of transcript splicing (rMATS) analysis to detect and quantify differential alternative splicing events. Reverse transcriptase-polymerase chain reaction (RT-PCR) for selected alternative splicing events was performed to validate RNA-Seq predictions. Functional enrichment was performed by gene ontology (GO) analysis of the differential alternative splicing event data set at each time point. RESULTS At least 600 differential alternative splicing events were detected at each time point tested, comprising all the five main types of alternative splicing and occurring in both open reading frames (ORFs) and untranslated regions (UTRs). Based on functional relevance ELK4, SHC1, and XRRA1 were selected for validation of predicted alternative splicing events at 7 wk by RT-PCR. Densitometric analysis of RT-PCR data corroborated the rMATS predicted alternative splicing for all three events. Protein expression validation of the selected alternative splicing events was challenging given that very few isoform-specific antibodies are available. GO analysis demonstrated that the enriched terms in differential alternatively spliced mRNAs changed dynamically with the time of exposure. Notably, RNA metabolism and splicing regulation pathways were enriched at the 7-wk time point, when the greatest number of differentially alternatively spliced mRNAs are detected. Our preliminary proteomic analysis demonstrated that the expression of the canonical isoforms of the splice regulators DDX42, RMB25, and SRRM2 were induced upon chronic arsenic exposure, corroborating the splicing predictions. DISCUSSION These results using cultures of HaCaT cells suggest that arsenic exposure disrupted an alternative splice factor network and induced time-dependent genome-wide differential alternative splicing that likely contributed to the changing proteomic landscape in arsenic-induced carcinogenesis. However, significant challenges remain in corroborating alternative splicing data at the proteomic level. https://doi.org/10.1289/EHP9676.
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Affiliation(s)
- Ana P. Ferragut Cardoso
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Laila Al-Eryani
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Mohammed Sayed
- Computer Science and Engineering, University of Louisville, Louisville, Kentucky, USA
| | - Daniel W. Wilkey
- Division of Nephrology & Hypertension, Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Michael L. Merchant
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
- Division of Nephrology & Hypertension, Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Juw W. Park
- Computer Science and Engineering, University of Louisville, Louisville, Kentucky, USA
- KY INBRE Bioinformatics Core, University of Louisville, Louisville, Kentucky, USA
| | - J. Christopher States
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
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14
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Borao S, Ayté J, Hümmer S. Evolution of the Early Spliceosomal Complex-From Constitutive to Regulated Splicing. Int J Mol Sci 2021; 22:ijms222212444. [PMID: 34830325 PMCID: PMC8624252 DOI: 10.3390/ijms222212444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 12/14/2022] Open
Abstract
Pre-mRNA splicing is a major process in the regulated expression of genes in eukaryotes, and alternative splicing is used to generate different proteins from the same coding gene. Splicing is a catalytic process that removes introns and ligates exons to create the RNA sequence that codifies the final protein. While this is achieved in an autocatalytic process in ancestral group II introns in prokaryotes, the spliceosome has evolved during eukaryogenesis to assist in this process and to finally provide the opportunity for intron-specific splicing. In the early stage of splicing, the RNA 5' and 3' splice sites must be brought within proximity to correctly assemble the active spliceosome and perform the excision and ligation reactions. The assembly of this first complex, termed E-complex, is currently the least understood process. We focused in this review on the formation of the E-complex and compared its composition and function in three different organisms. We highlight the common ancestral mechanisms in S. cerevisiae, S. pombe, and mammals and conclude with a unifying model for intron definition in constitutive and regulated co-transcriptional splicing.
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Affiliation(s)
- Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Correspondence: (J.A.); (S.H.)
| | - Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Translational Molecular Pathology, Vall d’Hebron Research Institute (VHIR), CIBERONC, 08035 Barcelona, Spain
- Correspondence: (J.A.); (S.H.)
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15
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Zhang Y, Yao X, Zhou H, Wu X, Tian J, Zeng J, Yan L, Duan C, Liu H, Li H, Chen K, Hu Z, Ye Z, Xu H. OncoSplicing: an updated database for clinically relevant alternative splicing in 33 human cancers. Nucleic Acids Res 2021; 50:D1340-D1347. [PMID: 34554251 PMCID: PMC8728274 DOI: 10.1093/nar/gkab851] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/06/2021] [Accepted: 09/13/2021] [Indexed: 11/24/2022] Open
Abstract
Alternative splicing (AS) represents a crucial method in mRNA level to regulate gene expression and contributes to the protein complexity. Abnormal splicing has been reported to play roles in several diseases, including cancers. We developed the OncoSplicing database for visualization of survival-associated and differential alternative splicing in 2019. Here, we provide an updated version of OncoSplicing for an integrative view of clinically relevant alternative splicing based on 122 423 AS events across 33 cancers in the TCGA SpliceSeq project and 238 558 AS events across 32 cancers in the TCGA SplAdder project. The new version of the database contains several useful features, such as annotation of alternative splicing-associated transcripts, survival analysis based on median and optimal cut-offs, differential analysis between TCGA tumour samples and adjacent normal samples or GTEx normal samples, pan-cancer views of alternative splicing, splicing differences and results of Cox’PH regression, identification of clinical indicator-relevant and cancer-specific splicing events, and downloadable splicing data in the SplAdder project. Overall, the substantially updated version of OncoSplicing (www.oncosplicing.com) is a user-friendly and registration-free database for browsing and searching clinically relevant alternative splicing in human cancers.
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Affiliation(s)
- Yangjun Zhang
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Xiangyang Yao
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Hui Zhou
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Xiaoliang Wu
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Jianbo Tian
- Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jin Zeng
- Department of Urology, The First Affiliated Hospital of Nanchang University, Nanchang 330000, China
| | - Libin Yan
- Department of Urology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Chen Duan
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Haoran Liu
- Department of Urology, The Second Affiliated Hospital of Kunming Medical University, Kunming 650000, China
| | - Heng Li
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Ke Chen
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Zhiquan Hu
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Zhangqun Ye
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology of Hubei Province, Wuhan 430030, China
| | - Hua Xu
- Institute of Urology of Hubei Province, Wuhan 430030, China.,Cancer Precision Diagnosis and Treatment and Translational Medicine Hubei Engineering Research Center, Wuhan 430030, China.,Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan 430030, China.,Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan 430030, China
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16
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Wartmann H, Heins S, Kloiber K, Bonn S. Bias-invariant RNA-sequencing metadata annotation. Gigascience 2021; 10:giab064. [PMID: 34553213 PMCID: PMC8559615 DOI: 10.1093/gigascience/giab064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 06/11/2021] [Accepted: 09/01/2021] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Recent technological advances have resulted in an unprecedented increase in publicly available biomedical data, yet the reuse of the data is often precluded by experimental bias and a lack of annotation depth and consistency. Missing annotations makes it impossible for researchers to find datasets specific to their needs. FINDINGS Here, we investigate RNA-sequencing metadata prediction based on gene expression values. We present a deep-learning-based domain adaptation algorithm for the automatic annotation of RNA-sequencing metadata. We show, in multiple experiments, that our model is better at integrating heterogeneous training data compared with existing linear regression-based approaches, resulting in improved tissue type classification. By using a model architecture similar to Siamese networks, the algorithm can learn biases from datasets with few samples. CONCLUSION Using our novel domain adaptation approach, we achieved metadata annotation accuracies up to 15.7% better than a previously published method. Using the best model, we provide a list of >10,000 novel tissue and sex label annotations for 8,495 unique SRA samples. Our approach has the potential to revive idle datasets by automated annotation making them more searchable.
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Affiliation(s)
- Hannes Wartmann
- Institute of Medical Systems Biology, Center for Biomedical AI, University
Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Sven Heins
- Institute of Medical Systems Biology, Center for Biomedical AI, University
Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Karin Kloiber
- Institute of Medical Systems Biology, Center for Biomedical AI, University
Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Stefan Bonn
- Institute of Medical Systems Biology, Center for Biomedical AI, University
Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
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17
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Márquez Y, Mantica F, Cozzuto L, Burguera D, Hermoso-Pulido A, Ponomarenko J, Roy SW, Irimia M. ExOrthist: a tool to infer exon orthologies at any evolutionary distance. Genome Biol 2021; 22:239. [PMID: 34416914 PMCID: PMC8379844 DOI: 10.1186/s13059-021-02441-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 07/26/2021] [Indexed: 12/14/2022] Open
Abstract
Several bioinformatic tools have been developed for genome-wide identification of orthologous and paralogous genes. However, no corresponding tool allows the detection of exon homology relationships. Here, we present ExOrthist, a fully reproducible Nextflow-based software enabling inference of exon homologs and orthogroups, visualization of evolution of exon-intron structures, and assessment of conservation of alternative splicing patterns. ExOrthist evaluates exon sequence conservation and considers the surrounding exon-intron context to derive genome-wide multi-species exon homologies at any evolutionary distance. We demonstrate its use in different evolutionary scenarios: whole genome duplication in frogs and convergence of Nova-regulated splicing networks (https://github.com/biocorecrg/ExOrthist).
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Affiliation(s)
- Yamile Márquez
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, 08003, Barcelona, Spain.
| | - Federica Mantica
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, 08003, Barcelona, Spain
| | - Luca Cozzuto
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, 08003, Barcelona, Spain
| | - Demian Burguera
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, 08003, Barcelona, Spain.,Department of Zoology, Charles University, Vinicna 7, 12844, Prague, Czech Republic
| | - Antonio Hermoso-Pulido
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, 08003, Barcelona, Spain
| | - Julia Ponomarenko
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, 08003, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Scott W Roy
- San Francisco State University, 1600 Holloway Ave, San Francisco, CA, 94132, USA
| | - Manuel Irimia
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Dr. Aiguader, 88, 08003, Barcelona, Spain. .,Universitat Pompeu Fabra, Barcelona, Spain. .,ICREA, Barcelona, Spain.
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18
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Martinez Gomez L, Pozo F, Walsh TA, Abascal F, Tress ML. The clinical importance of tandem exon duplication-derived substitutions. Nucleic Acids Res 2021; 49:8232-8246. [PMID: 34302486 PMCID: PMC8373072 DOI: 10.1093/nar/gkab623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/21/2021] [Indexed: 01/04/2023] Open
Abstract
Most coding genes in the human genome are annotated with multiple alternative transcripts. However, clear evidence for the functional relevance of the protein isoforms produced by these alternative transcripts is often hard to find. Alternative isoforms generated from tandem exon duplication-derived substitutions are an exception. These splice events are rare, but have important functional consequences. Here, we have catalogued the 236 tandem exon duplication-derived substitutions annotated in the GENCODE human reference set. We find that more than 90% of the events have a last common ancestor in teleost fish, so are at least 425 million years old, and twenty-one can be traced back to the Bilateria clade. Alternative isoforms generated from tandem exon duplication-derived substitutions also have significantly more clinical impact than other alternative isoforms. Tandem exon duplication-derived substitutions have >25 times as many pathogenic and likely pathogenic mutations as other alternative events. Tandem exon duplication-derived substitutions appear to have vital functional roles in the cell and may have played a prominent part in metazoan evolution.
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Affiliation(s)
- Laura Martinez Gomez
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), C. Melchor Fernandez Almagro, 3, 28029 Madrid, Spain
| | - Fernando Pozo
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), C. Melchor Fernandez Almagro, 3, 28029 Madrid, Spain
| | - Thomas A Walsh
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), C. Melchor Fernandez Almagro, 3, 28029 Madrid, Spain.,Eukaryotic Annotation Team, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA. UK
| | - Federico Abascal
- Somatic Evolution Group, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Michael L Tress
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), C. Melchor Fernandez Almagro, 3, 28029 Madrid, Spain
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19
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Zhu C, Wu J, Sun H, Briganti F, Meder B, Wei W, Steinmetz LM. Single-molecule, full-length transcript isoform sequencing reveals disease-associated RNA isoforms in cardiomyocytes. Nat Commun 2021; 12:4203. [PMID: 34244519 PMCID: PMC8270901 DOI: 10.1038/s41467-021-24484-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/22/2021] [Indexed: 01/06/2023] Open
Abstract
Alternative splicing generates differing RNA isoforms that govern phenotypic complexity of eukaryotes. Its malfunction underlies many diseases, including cancer and cardiovascular diseases. Comparative analysis of RNA isoforms at the genome-wide scale has been difficult. Here, we establish an experimental and computational pipeline that performs de novo transcript annotation and accurately quantifies transcript isoforms from cDNA sequences with a full-length isoform detection accuracy of 97.6%. We generate a searchable, quantitative human transcriptome annotation with 31,025 known and 5,740 novel transcript isoforms ( http://steinmetzlab.embl.de/iBrowser/ ). By analyzing the isoforms in the presence of RNA Binding Motif Protein 20 (RBM20) mutations associated with aggressive dilated cardiomyopathy (DCM), we identify 121 differentially expressed transcript isoforms in 107 cardiac genes. Our approach enables quantitative dissection of complex transcript architecture instead of mere identification of inclusion or exclusion of individual exons, as exemplified by the discovery of IMMT isoforms mis-spliced by RBM20 mutations. Thereby we achieve a path to direct differential expression testing independent of an existing annotation of transcript isoforms, providing more immediate biological interpretation and higher resolution transcriptome comparisons.
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Affiliation(s)
- Chenchen Zhu
- Department of Genetics, School of Medicine, Stanford University, Stanford, USA
| | - Jingyan Wu
- Department of Genetics, School of Medicine, Stanford University, Stanford, USA
| | - Han Sun
- Department of Genetics, School of Medicine, Stanford University, Stanford, USA
| | - Francesca Briganti
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, USA
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Benjamin Meder
- Department of Genetics, School of Medicine, Stanford University, Stanford, USA
- Institute for Cardiomyopathies Heidelberg (ICH), Heart Center Heidelberg, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), partner site Heidelberg, Heidelberg, Germany
- Department of Medicine III, University of Heidelberg, Heidelberg, Germany
| | - Wu Wei
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.
- Center for Biomedical Informatics, Shanghai Engineering Research Center for Big Data in Pediatric Precision Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.
- Stanford Genome Technology Center, Stanford University, Palo Alto, USA.
| | - Lars M Steinmetz
- Department of Genetics, School of Medicine, Stanford University, Stanford, USA.
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany.
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, USA.
- Stanford Genome Technology Center, Stanford University, Palo Alto, USA.
- DZHK (German Center for Cardiovascular Research), partner site EMBL Heidelberg, Heidelberg, Germany.
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20
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Herbrechter R, Hube N, Buchholz R, Reiner A. Splicing and editing of ionotropic glutamate receptors: a comprehensive analysis based on human RNA-Seq data. Cell Mol Life Sci 2021; 78:5605-5630. [PMID: 34100982 PMCID: PMC8257547 DOI: 10.1007/s00018-021-03865-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 05/12/2021] [Accepted: 05/22/2021] [Indexed: 12/11/2022]
Abstract
Ionotropic glutamate receptors (iGluRs) play key roles for signaling in the central nervous system. Alternative splicing and RNA editing are well-known mechanisms to increase iGluR diversity and to provide context-dependent regulation. Earlier work on isoform identification has focused on the analysis of cloned transcripts, mostly from rodents. We here set out to obtain a systematic overview of iGluR splicing and editing in human brain based on RNA-Seq data. Using data from two large-scale transcriptome studies, we established a workflow for the de novo identification and quantification of alternative splice and editing events. We detected all canonical iGluR splice junctions, assessed the abundance of alternative events described in the literature, and identified new splice events in AMPA, kainate, delta, and NMDA receptor subunits. Notable events include an abundant transcript encoding the GluA4 amino-terminal domain, GluA4-ATD, a novel C-terminal GluD1 (delta receptor 1) isoform, GluD1-b, and potentially new GluK4 and GluN2C isoforms. C-terminal GluN1 splicing may be controlled by inclusion of a cassette exon, which shows preference for one of the two acceptor sites in the last exon. Moreover, we identified alternative untranslated regions (UTRs) and species-specific differences in splicing. In contrast, editing in exonic iGluR regions appears to be mostly limited to ten previously described sites, two of which result in silent amino acid changes. Coupling of proximal editing/editing and editing/splice events occurs to variable degree. Overall, this analysis provides the first inventory of alternative splicing and editing in human brain iGluRs and provides the impetus for further transcriptome-based and functional investigations.
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Affiliation(s)
- Robin Herbrechter
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Nadine Hube
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Raoul Buchholz
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Andreas Reiner
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
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21
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Okay K, Varış PÜ, Miral S, Ekinci B, Yaraş T, Karakülah G, Oktay Y. Alternative splicing and gene co-expression network-based analysis of dizygotic twins with autism-spectrum disorder and their parents. Genomics 2021; 113:2561-2571. [PMID: 34087420 DOI: 10.1016/j.ygeno.2021.05.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 11/25/2022]
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder with high heritability, however, understanding the complexity of the underlying genetic basis has proven to be a challenging task. We hypothesized that dissecting the aberrations in alternative splicing (AS) and their effects on expression networks might provide insight. Therefore, we performed AS and co-expression analyses of total RNA isolated from Peripheral Blood Mononuclear Cells (PBMCs) of two pairs of dizygotic (DZ) twins with non-syndromic autism and their parents. We identified 183 differential AS events in 146 genes, seven of them being Simons Foundation Autism Research Initiative (SFARI) Category 1-3 genes, three of which had previously been reported to be alternatively spliced in ASD post-mortem brains. Gene co-expression analysis identified 7 modules with 513 genes, 5 of which were SFARI Category 1 or Category 2 genes. Among differentially AS genes within the modules, ZNF322 and NR4A1 could be potentially interesting targets for further investigations.
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Affiliation(s)
- Kaan Okay
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Balçova, Izmir, Turkey; Izmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, Balçova, Izmir, Turkey
| | - Pelin Ünal Varış
- Department of Child and Adolescent Psychiatry, Faculty of Medicine, Dokuz Eylül University, Balçova, Izmir, Turkey; Barış Psychiatric Hospital, Nicosia, Cyprus
| | - Süha Miral
- Department of Child and Adolescent Psychiatry, Faculty of Medicine, Dokuz Eylül University, Balçova, Izmir, Turkey
| | - Burcu Ekinci
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Balçova, Izmir, Turkey; Izmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, Balçova, Izmir, Turkey
| | - Tutku Yaraş
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Balçova, Izmir, Turkey; Izmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, Balçova, Izmir, Turkey
| | - Gökhan Karakülah
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Balçova, Izmir, Turkey; Izmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, Balçova, Izmir, Turkey.
| | - Yavuz Oktay
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Balçova, Izmir, Turkey; Izmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, Balçova, Izmir, Turkey; Department of Medical Biology, Faculty of Medicine, Dokuz Eylül University, Balçova, Izmir, Turkey.
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22
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Dong H, Li L, Zhu X, Shi J, Fu Y, Zhang S, Shi Y, Xu B, Zhang J, Shi F, Jin Y. Complex RNA Secondary Structures Mediate Mutually Exclusive Splicing of Coleoptera Dscam1. Front Genet 2021; 12:644238. [PMID: 33859670 PMCID: PMC8042237 DOI: 10.3389/fgene.2021.644238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/23/2021] [Indexed: 11/13/2022] Open
Abstract
Mutually exclusive splicing is an important mechanism for expanding protein diversity. An extreme example is the Down syndrome cell adhesion molecular (Dscam1) gene of insects, containing four clusters of variable exons (exons 4, 6, 9, and 17), which potentially generates tens of thousands of protein isoforms through mutually exclusive splicing, of which regulatory mechanisms are still elusive. Here, we systematically analyzed the variable exon 4, 6, and 9 clusters of Dscam1 in Coleoptera species. Through comparative genomics and RNA secondary structure prediction, we found apparent evidence that the evolutionarily conserved RNA base pairing mediates mutually exclusive splicing in the Dscam1 exon 4 cluster. In contrast to the fly exon 6, most exon 6 selector sequences in Coleoptera species are partially located in the variable exon region. Besides, bidirectional RNA–RNA interactions are predicted to regulate the mutually exclusive splicing of variable exon 9 of Dscam1. Although the docking sites in exon 4 and 9 clusters are clade specific, the docking sites-selector base pairing is conserved in secondary structure level. In short, our result provided a mechanistic framework for the application of long-range RNA base pairings in regulating the mutually exclusive splicing of Coleoptera Dscam1.
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Affiliation(s)
- Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xiaohua Zhu
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yang Shi
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jian Zhang
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis, Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
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23
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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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24
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Lam SD, Babu MM, Lees J, Orengo CA. Biological impact of mutually exclusive exon switching. PLoS Comput Biol 2021; 17:e1008708. [PMID: 33651795 PMCID: PMC7954323 DOI: 10.1371/journal.pcbi.1008708] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 03/12/2021] [Accepted: 01/14/2021] [Indexed: 12/27/2022] Open
Abstract
Alternative splicing can expand the diversity of proteomes. Homologous mutually exclusive exons (MXEs) originate from the same ancestral exon and result in polypeptides with similar structural properties but altered sequence. Why would some genes switch homologous exons and what are their biological impact? Here, we analyse the extent of sequence, structural and functional variability in MXEs and report the first large scale, structure-based analysis of the biological impact of MXE events from different genomes. MXE-specific residues tend to map to single domains, are highly enriched in surface exposed residues and cluster at or near protein functional sites. Thus, MXE events are likely to maintain the protein fold, but alter specificity and selectivity of protein function. This comprehensive resource of MXE events and their annotations is available at: http://gene3d.biochem.ucl.ac.uk/mxemod/. These findings highlight how small, but significant changes at critical positions on a protein surface are exploited in evolution to alter function.
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Affiliation(s)
- Su Datt Lam
- Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, United Kingdom
- Department of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Malaysia
- * E-mail: (SDL); (JL); (CO)
| | - M. Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Structural Biology and Center for Data Driven Discovery, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Jonathan Lees
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
- * E-mail: (SDL); (JL); (CO)
| | - Christine A. Orengo
- Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, United Kingdom
- * E-mail: (SDL); (JL); (CO)
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25
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Kalinina M, Skvortsov D, Kalmykova S, Ivanov T, Dontsova O, Pervouchine D. Multiple competing RNA structures dynamically control alternative splicing in the human ATE1 gene. Nucleic Acids Res 2021; 49:479-490. [PMID: 33330934 PMCID: PMC7797038 DOI: 10.1093/nar/gkaa1208] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/07/2020] [Accepted: 11/28/2020] [Indexed: 11/14/2022] Open
Abstract
The mammalian Ate1 gene encodes an arginyl transferase enzyme with tumor suppressor function that depends on the inclusion of one of the two mutually exclusive exons (MXE), exons 7a and 7b. We report that the molecular mechanism underlying MXE splicing in Ate1 involves five conserved regulatory intronic elements R1-R5, of which R1 and R4 compete for base pairing with R3, while R2 and R5 form an ultra-long-range RNA structure spanning 30 Kb. In minigenes, single and double mutations that disrupt base pairings in R1R3 and R3R4 lead to the loss of MXE splicing, while compensatory triple mutations that restore RNA structure revert splicing to that of the wild type. In the endogenous Ate1 pre-mRNA, blocking the competing base pairings by LNA/DNA mixmers complementary to R3 leads to the loss of MXE splicing, while the disruption of R2R5 interaction changes the ratio of MXE. That is, Ate1 splicing is controlled by two independent, dynamically interacting, and functionally distinct RNA structure modules. Exon 7a becomes more included in response to RNA Pol II slowdown, however it fails to do so when the ultra-long-range R2R5 interaction is disrupted, indicating that exon 7a/7b ratio depends on co-transcriptional RNA folding. In sum, these results demonstrate that splicing is coordinated both in time and in space over very long distances, and that the interaction of these components is mediated by RNA structure.
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Affiliation(s)
- Marina Kalinina
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
| | - Dmitry Skvortsov
- Moscow State University, Faculty of Chemistry, Moscow 119991, Russia
| | - Svetlana Kalmykova
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
| | - Timofei Ivanov
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
| | - Olga Dontsova
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
- Moscow State University, Faculty of Chemistry, Moscow 119991, Russia
| | - Dmitri D Pervouchine
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
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26
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Kubick N, Henckell Flournoy PC, Klimovich P, Manda G, Mickael M. What has single-cell RNA sequencing revealed about microglial neuroimmunology? Immun Inflamm Dis 2020; 8:825-839. [PMID: 33085226 PMCID: PMC7654416 DOI: 10.1002/iid3.362] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/03/2020] [Accepted: 10/05/2020] [Indexed: 12/22/2022] Open
Abstract
The use of single-cell RNA sequencing (scRNA-seq) in microglial research is increasing rapidly. The basic workflow of this approach consists of isolating single cells, followed by sequencing. scRNA-seq is capable of examining microglial heterogeneity on a cellular level. However, the results gained from applying this technique suffer from discrepancies due to differences between applied methods characteristics such as the number of cells sequenced and the depth of sequencing. This review aims to shed more light on the recent developments that happened in this field and how they are related to the methods used. To do that, we track the progress and limitations of various scRNA-seq methods currently available. The review then summarizes the current knowledge gained using scRNA-seq in the field of microglia, including novel subpopulations associated with function and development under homeostasis as well during several pathological conditions such as Alzheimer, lipopolysaccharide response, and HIV in relation to the methods employed. Our review points out that despite major developments found using this technique, current scRNA-seq methods suffer from high cost, low yields, and nonstandardization of generated data. Additional development of scRNA-seq methods will raise our awareness of microglia's heterogeneity and plasticity under healthy and pathological conditions.
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Affiliation(s)
- Norwin Kubick
- Department of Biochemistry and Molecular Cell Biology (IBMZ)University Medical Center Hamburg‐EppendorfHamburgGermany
| | | | - Pavel Klimovich
- Department of ImmunologyPM Research CenterStockholmEkeröSweden
| | - Gina Manda
- Department of RadiologyVictor Babes National Institute of PathologyBucharestRomania
| | - Michel‐Edwar Mickael
- Department of ImmunologyPM Research CenterStockholmEkeröSweden
- Department of PathologyBevill Biomedical SciencesBirminghamAlabamaUSA
- Department of Experimental Genomics, Neuroimmunology Group, Institute of Genetics and Animal BiotechnologyPolish Academy of ScienceMagdalenkaPoland
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27
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Abstract
Systematics is described for annotation of variations in RNA molecules. The conceptual framework is part of Variation Ontology (VariO) and facilitates depiction of types of variations, their functional and structural effects and other consequences in any RNA molecule in any organism. There are more than 150 RNA related VariO terms in seven levels, which can be further combined to generate even more complicated and detailed annotations. The terms are described together with examples, usually for variations and effects in human and in diseases. RNA variation type has two subcategories: variation classification and origin with subterms. Altogether six terms are available for function description. Several terms are available for affected RNA properties. The ontology contains also terms for structural description for affected RNA type, post-transcriptional RNA modifications, secondary and tertiary structure effects and RNA sugar variations. Together with the DNA and protein concepts and annotations, RNA terms allow comprehensive description of variations of genetic and non-genetic origin at all possible levels. The VariO annotations are readable both for humans and computer programs for advanced data integration and mining.
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Affiliation(s)
- Mauno Vihinen
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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28
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Xu B, Meng Y, Jin Y. RNA structures in alternative splicing and back-splicing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1626. [PMID: 32929887 DOI: 10.1002/wrna.1626] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/14/2020] [Accepted: 08/22/2020] [Indexed: 12/12/2022]
Abstract
Alternative splicing greatly expands the transcriptomic and proteomic diversities related to physiological and developmental processes in higher eukaryotes. Splicing of long noncoding RNAs, and back- and trans- splicing further expanded the regulatory repertoire of alternative splicing. RNA structures were shown to play an important role in regulating alternative splicing and back-splicing. Application of novel sequencing technologies made it possible to identify genome-wide RNA structures and interaction networks, which might provide new insights into RNA splicing regulation in vitro to in vivo. The emerging transcription-folding-splicing paradigm is changing our understanding of RNA alternative splicing regulation. Here, we review the insights into the roles and mechanisms of RNA structures in alternative splicing and back-splicing, as well as how disruption of these structures affects alternative splicing and then leads to human diseases. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
| | - Yijun Meng
- College of Life and Environmental Sciences, Hangzhou Normal University, Zhejiang, Hangzhou, China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, China
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29
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Hong W, Shi Y, Xu B, Jin Y. RNA secondary structures in Dscam1 mutually exclusive splicing: unique evolutionary signature from the midge. RNA (NEW YORK, N.Y.) 2020; 26:1086-1093. [PMID: 32471818 PMCID: PMC7430681 DOI: 10.1261/rna.075259.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/27/2020] [Indexed: 05/12/2023]
Abstract
The Drosophila melanogaster gene Dscam1 potentially generates 38,016 distinct isoforms via mutually exclusive splicing, which are required for both nervous and immune functions. However, the mechanism underlying splicing regulation remains obscure. Here we show apparent evolutionary signatures characteristic of competing RNA secondary structures in exon clusters 6 and 9 of Dscam1 in the two midge species (Belgica antarctica and Clunio marinus). Surprisingly, midge Dscam1 encodes only ∼6000 different isoforms through mutually exclusive splicing. Strikingly, the docking site of the exon 6 cluster is conserved in almost all insects and crustaceans but is specific in the midge; however, the docking site-selector base-pairings are conserved. Moreover, the docking site is complementary to all predicted selector sequences downstream from every variable exon 9 of the midge Dscam1, which is in accordance with the broad spectrum of their isoform expression. This suggests that these cis-elements mainly function through the formation of long-range base-pairings. This study provides a vital insight into the evolution and mechanism of Dscam1 alternative splicing.
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Affiliation(s)
- Weiling Hong
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, China
| | - Yang Shi
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, China
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30
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Tzani I, Monger C, Motheramgari K, Gallagher C, Hagan R, Kelly P, Costello A, Meiller J, Floris P, Zhang L, Clynes M, Bones J, Barron N, Clarke C. Subphysiological temperature induces pervasive alternative splicing in Chinese hamster ovary cells. Biotechnol Bioeng 2020; 117:2489-2503. [DOI: 10.1002/bit.27365] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/01/2020] [Accepted: 04/26/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Ioanna Tzani
- National Institute for Bioprocessing Research and Training Dublin Ireland
| | - Craig Monger
- National Institute for Bioprocessing Research and Training Dublin Ireland
| | - Krishna Motheramgari
- National Institute for Bioprocessing Research and Training Dublin Ireland
- National Institute for Cellular BiotechnologyDublin City University Glasnevin Dublin Ireland
| | - Clair Gallagher
- National Institute for Cellular BiotechnologyDublin City University Glasnevin Dublin Ireland
| | - Ryan Hagan
- National Institute for Bioprocessing Research and Training Dublin Ireland
- School of Chemical and Bioprocess EngineeringUniversity College Dublin Dublin Ireland
| | - Paul Kelly
- National Institute for Cellular BiotechnologyDublin City University Glasnevin Dublin Ireland
| | - Alan Costello
- National Institute for Cellular BiotechnologyDublin City University Glasnevin Dublin Ireland
| | - Justine Meiller
- National Institute for Cellular BiotechnologyDublin City University Glasnevin Dublin Ireland
| | - Patrick Floris
- National Institute for Bioprocessing Research and Training Dublin Ireland
| | - Lin Zhang
- Bioprocess R&DPfizer Inc. Andover Massachusetts
| | - Martin Clynes
- National Institute for Cellular BiotechnologyDublin City University Glasnevin Dublin Ireland
| | - Jonathan Bones
- National Institute for Bioprocessing Research and Training Dublin Ireland
- School of Chemical and Bioprocess EngineeringUniversity College Dublin Dublin Ireland
| | - Niall Barron
- National Institute for Bioprocessing Research and Training Dublin Ireland
- School of Chemical and Bioprocess EngineeringUniversity College Dublin Dublin Ireland
| | - Colin Clarke
- National Institute for Bioprocessing Research and Training Dublin Ireland
- School of Chemical and Bioprocess EngineeringUniversity College Dublin Dublin Ireland
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31
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de la Fuente L, Arzalluz-Luque Á, Tardáguila M, Del Risco H, Martí C, Tarazona S, Salguero P, Scott R, Lerma A, Alastrue-Agudo A, Bonilla P, Newman JRB, Kosugi S, McIntyre LM, Moreno-Manzano V, Conesa A. tappAS: a comprehensive computational framework for the analysis of the functional impact of differential splicing. Genome Biol 2020; 21:119. [PMID: 32423416 PMCID: PMC7236505 DOI: 10.1186/s13059-020-02028-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/23/2020] [Indexed: 12/26/2022] Open
Abstract
Recent advances in long-read sequencing solve inaccuracies in alternative transcript identification of full-length transcripts in short-read RNA-Seq data, which encourages the development of methods for isoform-centered functional analysis. Here, we present tappAS, the first framework to enable a comprehensive Functional Iso-Transcriptomics (FIT) analysis, which is effective at revealing the functional impact of context-specific post-transcriptional regulation. tappAS uses isoform-resolved annotation of coding and non-coding functional domains, motifs, and sites, in combination with novel analysis methods to interrogate different aspects of the functional readout of transcript variants and isoform regulation. tappAS software and documentation are available at https://app.tappas.org.
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Affiliation(s)
- Lorena de la Fuente
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
- Present Address: Bioinformatics Unit, IIS Fundación Jiménez Díaz, Madrid, Spain
| | - Ángeles Arzalluz-Luque
- Department of Statistics and Operational Research, Polytechnical University of Valencia, Valencia, Spain
| | - Manuel Tardáguila
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
- Present Address: Human Genetics Department, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Héctor Del Risco
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
| | - Cristina Martí
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
| | - Sonia Tarazona
- Department of Statistics and Operational Research, Polytechnical University of Valencia, Valencia, Spain
| | - Pedro Salguero
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
| | - Raymond Scott
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
| | - Alberto Lerma
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
| | - Ana Alastrue-Agudo
- Present Address: Human Genetics Department, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Pablo Bonilla
- Present Address: Human Genetics Department, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Jeremy R B Newman
- Genetics Institute, University of Florida, Gainesville, FL, USA
- Department of Pathology, University of Florida, Gainesville, FL, USA
| | - Shunichi Kosugi
- Genetics Institute, University of Florida, Gainesville, FL, USA
- Laboratory for Statistical and Translational Genetics, Center for Integrative Medical Sciences, RIKEN, Wako, Japan
| | - Lauren M McIntyre
- Genetics Institute, University of Florida, Gainesville, FL, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | | | - Ana Conesa
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA.
- Genetics Institute, University of Florida, Gainesville, FL, USA.
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32
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Thalhammer A, Jaudon F, Cingolani LA. Emerging Roles of Activity-Dependent Alternative Splicing in Homeostatic Plasticity. Front Cell Neurosci 2020; 14:104. [PMID: 32477067 PMCID: PMC7235277 DOI: 10.3389/fncel.2020.00104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022] Open
Abstract
Homeostatic plasticity refers to the ability of neuronal networks to stabilize their activity in the face of external perturbations. Most forms of homeostatic plasticity ultimately depend on changes in the expression or activity of ion channels and synaptic proteins, which may occur at the gene, transcript, or protein level. The most extensively investigated homeostatic mechanisms entail adaptations in protein function or localization following activity-dependent posttranslational modifications. Numerous studies have also highlighted how homeostatic plasticity can be achieved by adjusting local protein translation at synapses or transcription of specific genes in the nucleus. In comparison, little attention has been devoted to whether and how alternative splicing (AS) of pre-mRNAs underlies some forms of homeostatic plasticity. AS not only expands proteome diversity but also contributes to the spatiotemporal dynamics of mRNA transcripts. Prominent in the brain where it can be regulated by neuronal activity, it is a flexible process, tightly controlled by a multitude of factors. Given its extensive use and versatility in optimizing the function of ion channels and synaptic proteins, we argue that AS is ideally suited to achieve homeostatic control of neuronal output. We support this thesis by reviewing emerging evidence linking AS to various forms of homeostatic plasticity: homeostatic intrinsic plasticity, synaptic scaling, and presynaptic homeostatic plasticity. Further, we highlight the relevance of this connection for brain pathologies.
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Affiliation(s)
- Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fanny Jaudon
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Lorenzo A Cingolani
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,Department of Life Sciences, University of Trieste, Trieste, Italy
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33
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Xu B, Shi Y, Wu Y, Meng Y, Jin Y. Role of RNA secondary structures in regulating Dscam alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194381. [DOI: 10.1016/j.bbagrm.2019.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/21/2019] [Accepted: 04/22/2019] [Indexed: 12/19/2022]
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Hatje K, Mühlhausen S, Simm D, Kollmar M. The Protein-Coding Human Genome: Annotating High-Hanging Fruits. Bioessays 2019; 41:e1900066. [PMID: 31544971 DOI: 10.1002/bies.201900066] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 08/07/2019] [Indexed: 12/19/2022]
Abstract
The major transcript variants of human protein-coding genes are annotated to a certain degree of accuracy combining manual curation, transcript data, and proteomics evidence. However, there is considerable disagreement on the annotation of about 2000 genes-they can be protein-coding, noncoding, or pseudogenes-and on the annotation of most of the predicted alternative transcripts. Pure transcriptome mapping approaches seem to be limited in discriminating functional expression from noise. These limitations have partially been overcome by dedicated algorithms to detect alternative spliced micro-exons and wobble splice variants. Recently, knowledge about splice mechanism and protein structure are incorporated into an algorithm to predict neighboring homologous exons, often spliced in a mutually exclusive manner. Predicted exons are evaluated by transcript data, structural compatibility, and evolutionary conservation, revealing hundreds of novel coding exons and splice mechanism re-assignments. The emerging human pan-genome is necessitating distinctive annotations incorporating differences between individuals and between populations.
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Affiliation(s)
- Klas Hatje
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstr. 124, 4070, Basel, Switzerland
| | - Stefanie Mühlhausen
- Group Systems Biology of Motor Proteins, Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Dominic Simm
- Group Systems Biology of Motor Proteins, Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Theoretical Computer Science and Algorithmic Methods, Institute of Computer Science, Georg-August-University Göttingen, Goldschmidtstr. 7, 37077, Göttingen, Germany
| | - Martin Kollmar
- Group Systems Biology of Motor Proteins, Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
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35
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Bartys N, Kierzek R, Lisowiec-Wachnicka J. The regulation properties of RNA secondary structure in alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194401. [PMID: 31323437 DOI: 10.1016/j.bbagrm.2019.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/09/2019] [Indexed: 11/30/2022]
Abstract
The RNA secondary structure is important for many functional processes in the cell. The secondary and tertiary structures of cellular RNAs are essential for the activity of these molecules in processes such as transcription, splicing, translation, and localization. New high-throughput analytical methods, including next generation sequencing, have allowed for the in-depth characterization of the 'RNA structurome': a new term describing how the RNA structure controls the activity of RNA by itself and how it regulates the expression of genes. In this review, we present many examples of the influence of structural motifs of RNA, long range interactions and global RNA structure on the alternative splicing processes. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Natalia Bartys
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Ryszard Kierzek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Jolanta Lisowiec-Wachnicka
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland.
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36
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Mathur M, Kim CM, Munro SA, Rudina SS, Sawyer EM, Smolke CD. Programmable mutually exclusive alternative splicing for generating RNA and protein diversity. Nat Commun 2019; 10:2673. [PMID: 31209208 PMCID: PMC6572816 DOI: 10.1038/s41467-019-10403-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/01/2019] [Indexed: 02/07/2023] Open
Abstract
Alternative splicing performs a central role in expanding genomic coding capacity and proteomic diversity. However, programming of splicing patterns in engineered biological systems remains underused. Synthetic approaches thus far have predominantly focused on controlling expression of a single protein through alternative splicing. Here, we describe a modular and extensible platform for regulating four programmable exons that undergo a mutually exclusive alternative splicing event to generate multiple functionally-distinct proteins. We present an intron framework that enforces the mutual exclusivity of two internal exons and demonstrate a graded series of consensus sequence elements of varying strengths that set the ratio of two mutually exclusive isoforms. We apply this framework to program the DNA-binding domains of modular transcription factors to differentially control downstream gene activation. This splicing platform advances an approach for generating diverse isoforms and can ultimately be applied to program modular proteins and increase coding capacity of synthetic biological systems.
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Affiliation(s)
- Melina Mathur
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Cameron M Kim
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Sarah A Munro
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Joint Initiative for Metrology in Biology, Stanford, CA, 94305, USA
- Genome-scale Measurements Group, National Institute of Standards and Technology, Stanford, CA, 94305, USA
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Shireen S Rudina
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Eric M Sawyer
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Christina D Smolke
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
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37
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Nord A, Carey K, Hornbeck P, Wheeler T. Splice-Aware Multiple Sequence Alignment of Protein Isoforms. ACM-BCB ... ... : THE ... ACM CONFERENCE ON BIOINFORMATICS, COMPUTATIONAL BIOLOGY AND BIOMEDICINE. ACM CONFERENCE ON BIOINFORMATICS, COMPUTATIONAL BIOLOGY AND BIOMEDICINE 2019; 2018:200-210. [PMID: 31080963 DOI: 10.1145/3233547.3233592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Multiple sequence alignment (MSA) is a classic problem in computational genomics. In typical use, MSA software is expected to align a collection of homologous genes, such as orthologs from multiple species or duplication-induced paralogs within a species. Recent focus on the importance of alternatively-spliced isoforms in disease and cell biology has highlighted the need to create MSAs that more effectively accommodate isoforms. MSAs are traditionally constructed using scoring criteria that prefer alignments with occasional mismatches over alignments with long gaps. Alternatively spliced protein isoforms effectively contain exon-length insertions or deletions (indels) relative to each other, and demand an alternative approach. Some improvements can be achieved by making indel penalties much smaller, but this is merely a patchwork solution. In this work we present Mirage, a novel MSA software package for the alignment of alternatively spliced protein isoforms. Mirage aligns isoforms to each other by first mapping each protein sequence to its encoding genomic sequence, and then aligning isoforms to one another based on the relative genomic coordinates of their constitutive codons. Mirage is highly effective at mapping proteins back to their encoding exons, and these protein-genome mappings lead to extremely accurate intra-species alignments; splice site information in these alignments is used to improve the accuracy of inter-species alignments of isoforms. Mirage alignments have also revealed the ubiquity of dual-coding exons, in which an exon conditionally encodes multiple open reading frames as overlapping spliced segments of frame-shifted genomic sequence.
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Affiliation(s)
- Alex Nord
- University of Montana Missoula, Montana,
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38
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Zhao S. Alternative splicing, RNA-seq and drug discovery. Drug Discov Today 2019; 24:1258-1267. [PMID: 30953866 DOI: 10.1016/j.drudis.2019.03.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/14/2019] [Accepted: 03/28/2019] [Indexed: 12/27/2022]
Abstract
Alternative splicing, hereafter referred to as AS, is an essential component of gene expression regulation that contributes to the diversity of proteomes. Recent developments in RNA sequencing (RNA-seq) technologies, combined with the advent of computational tools, have enabled transcriptome-wide studies of AS at an unprecedented scale and resolution. RNA mis-splicing can cause human disease, and to target alternative splicing has led to the development of novel therapeutics. Splice variants diversify the repertoire of biomarkers and functionally contribute to drug resistance. Our expanding knowledge of AS variation in human populations holds great promise for improving disease diagnoses and ultimately patient care in the era of sequencing and precision medicine.
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Affiliation(s)
- Shanrong Zhao
- Pfizer Worldwide Research and Development, Cambridge, MA 02139, USA.
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39
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Pan H, Shi Y, Chen S, Yang Y, Yue Y, Zhan L, Dai L, Dong H, Hong W, Shi F, Jin Y. Competing RNA pairings in complex alternative splicing of a 3' variable region. RNA (NEW YORK, N.Y.) 2018; 24:1466-1480. [PMID: 30065023 PMCID: PMC6191721 DOI: 10.1261/rna.066225.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/24/2018] [Indexed: 05/15/2023]
Abstract
Alternative pre-mRNA splicing remarkably expands protein diversity in eukaryotes. Drosophila PGRP-LC can generate three major 3' splice isoforms that exhibit distinct innate immune recognition and defenses against various microbial infections. However, the regulatory mechanisms underlying the uniquely biased splicing pattern at the 3' variable region remain unclear. Here we show that competing RNA pairings control the unique splicing of the 3' variable region of Drosophila PGRP-LC pre-mRNA. We reveal three roles by which these RNA pairings jointly regulate the 3' variant selection through activating the proximal 3' splice site and concurrently masking the intron-proximal 5' splice site, in combination with physical competition of RNA pairing. We also reveal that competing RNA pairings regulate alternative splicing of the highly complex 3' variable regions of Drosophila CG42235 and Pip Our findings will facilitate a better understanding of the regulatory mechanisms of highly complex alternative splicing as well as highly variable 3' processing.
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Affiliation(s)
- Huawei Pan
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yang Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Shuo Chen
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yun Yang
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yuan Yue
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Leilei Zhan
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Lanzhi Dai
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Haiyang Dong
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Weiling Hong
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Feng Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
| | - Yongfeng Jin
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, ZJ310058, P.R. China
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40
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Kahles A, Lehmann KV, Toussaint NC, Hüser M, Stark SG, Sachsenberg T, Stegle O, Kohlbacher O, Sander C, Rätsch G. Comprehensive Analysis of Alternative Splicing Across Tumors from 8,705 Patients. Cancer Cell 2018; 34:211-224.e6. [PMID: 30078747 PMCID: PMC9844097 DOI: 10.1016/j.ccell.2018.07.001] [Citation(s) in RCA: 513] [Impact Index Per Article: 85.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 03/30/2018] [Accepted: 07/02/2018] [Indexed: 01/19/2023]
Abstract
Our comprehensive analysis of alternative splicing across 32 The Cancer Genome Atlas cancer types from 8,705 patients detects alternative splicing events and tumor variants by reanalyzing RNA and whole-exome sequencing data. Tumors have up to 30% more alternative splicing events than normal samples. Association analysis of somatic variants with alternative splicing events confirmed known trans associations with variants in SF3B1 and U2AF1 and identified additional trans-acting variants (e.g., TADA1, PPP2R1A). Many tumors have thousands of alternative splicing events not detectable in normal samples; on average, we identified ≈930 exon-exon junctions ("neojunctions") in tumors not typically found in GTEx normals. From Clinical Proteomic Tumor Analysis Consortium data available for breast and ovarian tumor samples, we confirmed ≈1.7 neojunction- and ≈0.6 single nucleotide variant-derived peptides per tumor sample that are also predicted major histocompatibility complex-I binders ("putative neoantigens").
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Affiliation(s)
- André Kahles
- ETH Zurich, Department of Computer Science, Zurich, Switzerland; Memorial Sloan Kettering Cancer Center, Computational Biology Department, New York, USA; University Hospital Zurich, Biomedical Informatics Research, Zurich, Switzerland; SIB Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Kjong-Van Lehmann
- ETH Zurich, Department of Computer Science, Zurich, Switzerland; Memorial Sloan Kettering Cancer Center, Computational Biology Department, New York, USA; University Hospital Zurich, Biomedical Informatics Research, Zurich, Switzerland; SIB Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Nora C Toussaint
- ETH Zurich, NEXUS Personalized Health Technologies, Zurich, Switzerland; SIB Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Matthias Hüser
- ETH Zurich, Department of Computer Science, Zurich, Switzerland; University Hospital Zurich, Biomedical Informatics Research, Zurich, Switzerland; SIB Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Stefan G Stark
- ETH Zurich, Department of Computer Science, Zurich, Switzerland; Memorial Sloan Kettering Cancer Center, Computational Biology Department, New York, USA; University Hospital Zurich, Biomedical Informatics Research, Zurich, Switzerland; SIB Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Timo Sachsenberg
- University of Tübingen, Department of Computer Science, Tübingen, Germany
| | - Oliver Stegle
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge, UK
| | - Oliver Kohlbacher
- University of Tübingen, Department of Computer Science, Tübingen, Germany; Center for Bioinformatics, University of Tübingen, Tübingen, Germany; Quantitative Biology Center, University of Tübingen, Tübingen, Germany; Biomolecular Interactions, Max Planck Institute for Developmental Biology, Tübingen, Germany; Institute for Translational Bioinformatics, University Medical Center, Tübingen, Germany
| | - Chris Sander
- Dana-Farber Cancer Institute, cBio Center, Department of Biostatistics and Computational Biology, Boston, MA, USA; Harvard Medical School, CompBio Collaboratory, Department of Cell Biology, Boston, USA
| | | | - Gunnar Rätsch
- ETH Zurich, Department of Computer Science, Zurich, Switzerland; Memorial Sloan Kettering Cancer Center, Computational Biology Department, New York, USA; University Hospital Zurich, Biomedical Informatics Research, Zurich, Switzerland; ETH Zurich, Department of Biology, Zurich, Switzerland; SIB Swiss Institute of Bioinformatics, Zurich, Switzerland.
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41
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An Evolutionary Mechanism for the Generation of Competing RNA Structures Associated with Mutually Exclusive Exons. Genes (Basel) 2018; 9:genes9070356. [PMID: 30018239 PMCID: PMC6071210 DOI: 10.3390/genes9070356] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/06/2018] [Accepted: 07/13/2018] [Indexed: 12/31/2022] Open
Abstract
Alternative splicing is a commonly-used mechanism of diversifying gene products. Mutually exclusive exons (MXE) represent a particular type of alternative splicing, in which one and only one exon from an array is included in the mature RNA. A number of genes with MXE do so by using a mechanism that depends on RNA structure. Transcripts of these genes contain multiple sites called selector sequences that are all complementary to a regulatory element called the docking site; only one of the competing base pairings can form at a time, which exposes one exon from the cluster to the spliceosome. MXE tend to have similar lengths and sequence content and are believed to originate through tandem genomic duplications. Here, we report that pre-mRNAs of this class of exons have an increased capacity to fold into competing secondary structures. We propose an evolutionary mechanism for the generation of such structures via duplications that affect not only exons, but also their adjacent introns with stem-loop structures. If one of the two arms of a stem-loop is duplicated, it will generate two selector sequences that compete for the same docking site, a pattern that is associated with MXE splicing. A similar partial duplication of two independent stem-loops produces a pattern that is consistent with the so-called bidirectional pairing model. These models explain why tandem exon duplications frequently result in mutually exclusive splicing.
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42
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Jin Y, Dong H, Shi Y, Bian L. Mutually exclusive alternative splicing of pre-mRNAs. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1468. [PMID: 29423937 DOI: 10.1002/wrna.1468] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 12/20/2017] [Accepted: 12/20/2017] [Indexed: 12/14/2022]
Abstract
Pre-mRNA alternative splicing is an important mechanism used to expand protein diversity in higher eukaryotes, and mutually exclusive splicing is a specific type of alternative splicing in which only one of the exons in a cluster is included in functional transcripts. The most extraordinary example of this is the Drosophila melanogaster Down's syndrome cell adhesion molecule gene (Dscam), which potentially encodes 38,016 different isoforms through mutually exclusive splicing. Mutually exclusive splicing is a unique and challenging model that can be used to elucidate the evolution, regulatory mechanism, and function of alternative splicing. The use of new approaches has not only greatly expanded the mutually exclusive exome, but has also enabled the systematic analyses of single-cell alternative splicing during development. Furthermore, the identification of long-range RNA secondary structures provides a mechanistic framework for the regulation of mutually exclusive splicing (i.e., Dscam splicing). This article reviews recent insights into the identification, underlying mechanism, and roles of mutually exclusive splicing. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Yongfeng Jin
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Haiyang Dong
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yang Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Lina Bian
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
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43
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Hatje K, Rahman RU, Vidal RO, Simm D, Hammesfahr B, Bansal V, Rajput A, Mickael ME, Sun T, Bonn S, Kollmar M. The landscape of human mutually exclusive splicing. Mol Syst Biol 2017; 13:959. [PMID: 29242366 PMCID: PMC5740500 DOI: 10.15252/msb.20177728] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Mutually exclusive splicing of exons is a mechanism of functional gene and protein diversification with pivotal roles in organismal development and diseases such as Timothy syndrome, cardiomyopathy and cancer in humans. In order to obtain a first genomewide estimate of the extent and biological role of mutually exclusive splicing in humans, we predicted and subsequently validated mutually exclusive exons (MXEs) using 515 publically available RNA‐Seq datasets. Here, we provide evidence for the expression of over 855 MXEs, 42% of which represent novel exons, increasing the annotated human mutually exclusive exome more than fivefold. The data provide strong evidence for the existence of large and multi‐cluster MXEs in higher vertebrates and offer new insights into MXE evolution. More than 82% of the MXE clusters are conserved in mammals, and five clusters have homologous clusters in Drosophila. Finally, MXEs are significantly enriched in pathogenic mutations and their spatio‐temporal expression might predict human disease pathology.
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Affiliation(s)
- Klas Hatje
- Group Systems Biology of Motor Proteins Department of NMR-Based Structural Biology Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.,Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany
| | - Raza-Ur Rahman
- Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany.,Center for Molecular Neurobiology, Institute of Medical Systems Biology University Clinic Hamburg-Eppendorf, Hamburg, Germany
| | - Ramon O Vidal
- Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany
| | - Dominic Simm
- Group Systems Biology of Motor Proteins Department of NMR-Based Structural Biology Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.,Theoretical Computer Science and Algorithmic Methods, Institute of Computer Science Georg-August-University, Göttingen, Germany
| | - Björn Hammesfahr
- Group Systems Biology of Motor Proteins Department of NMR-Based Structural Biology Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Vikas Bansal
- Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany.,Center for Molecular Neurobiology, Institute of Medical Systems Biology University Clinic Hamburg-Eppendorf, Hamburg, Germany
| | - Ashish Rajput
- Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany.,Center for Molecular Neurobiology, Institute of Medical Systems Biology University Clinic Hamburg-Eppendorf, Hamburg, Germany
| | - Michel Edwar Mickael
- Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany.,Center for Molecular Neurobiology, Institute of Medical Systems Biology University Clinic Hamburg-Eppendorf, Hamburg, Germany
| | - Ting Sun
- Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany.,Center for Molecular Neurobiology, Institute of Medical Systems Biology University Clinic Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan Bonn
- Group of Computational Systems Biology, German Center for Neurodegenerative Diseases, Göttingen, Germany .,Center for Molecular Neurobiology, Institute of Medical Systems Biology University Clinic Hamburg-Eppendorf, Hamburg, Germany.,German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Martin Kollmar
- Group Systems Biology of Motor Proteins Department of NMR-Based Structural Biology Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
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