1
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Xiao MS, Damodaran AP, Kumari B, Dickson E, Xing K, On TA, Parab N, King HE, Perez AR, Guiblet WM, Duncan G, Che A, Chari R, Andresson T, Vidigal JA, Weatheritt RJ, Aregger M, Gonatopoulos-Pournatzis T. Genome-scale exon perturbation screens uncover exons critical for cell fitness. Mol Cell 2024; 84:2553-2572.e19. [PMID: 38917794 PMCID: PMC11246229 DOI: 10.1016/j.molcel.2024.05.024] [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: 10/01/2023] [Revised: 04/04/2024] [Accepted: 05/24/2024] [Indexed: 06/27/2024]
Abstract
CRISPR-Cas technology has transformed functional genomics, yet understanding of how individual exons differentially shape cellular phenotypes remains limited. Here, we optimized and conducted massively parallel exon deletion and splice-site mutation screens in human cell lines to identify exons that regulate cellular fitness. Fitness-promoting exons are prevalent in essential and highly expressed genes and commonly overlap with protein domains and interaction interfaces. Conversely, fitness-suppressing exons are enriched in nonessential genes, exhibiting lower inclusion levels, and overlap with intrinsically disordered regions and disease-associated mutations. In-depth mechanistic investigation of the screen-hit TAF5 alternative exon-8 revealed that its inclusion is required for assembly of the TFIID general transcription initiation complex, thereby regulating global gene expression output. Collectively, our orthogonal exon perturbation screens established a comprehensive repository of phenotypically important exons and uncovered regulatory mechanisms governing cellular fitness and gene expression.
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Affiliation(s)
- Mei-Sheng Xiao
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA
| | - Arun Prasath Damodaran
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA.
| | - Bandana Kumari
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA
| | - Ethan Dickson
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA
| | - Kun Xing
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA
| | - Tyler A On
- Molecular Targets Program, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA
| | - Nikhil Parab
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA
| | - Helen E King
- EMBL Australia and Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Alexendar R Perez
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD 20892, USA; Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Wilfried M Guiblet
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA
| | - Gerard Duncan
- Protein Characterization Laboratory, Frederick National Laboratory for Cancer Research (FNLCR), Frederick, MD 21701, USA
| | - Anney Che
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research (FNLCR), Frederick, MD 21701, USA
| | - Raj Chari
- Genome Modification Core, Frederick National Laboratory for Cancer Research (FNLCR), Frederick, MD 21702, USA
| | - Thorkell Andresson
- Protein Characterization Laboratory, Frederick National Laboratory for Cancer Research (FNLCR), Frederick, MD 21701, USA
| | - Joana A Vidigal
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Robert J Weatheritt
- EMBL Australia and Garvan Institute of Medical Research, Sydney, NSW 2010, Australia; School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2010, Australia
| | - Michael Aregger
- Molecular Targets Program, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA.
| | - Thomas Gonatopoulos-Pournatzis
- RNA Biology Laboratory, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Frederick, MD 21702, USA.
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2
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Ulicevic J, Shao Z, Jasnovidova O, Bressin A, Gajos M, Ng AH, Annaldasula S, Meierhofer D, Church GM, Busskamp V, Mayer A. Uncovering the dynamics and consequences of RNA isoform changes during neuronal differentiation. Mol Syst Biol 2024; 20:767-798. [PMID: 38755290 PMCID: PMC11219738 DOI: 10.1038/s44320-024-00039-4] [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: 10/20/2023] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 05/18/2024] Open
Abstract
Static gene expression programs have been extensively characterized in stem cells and mature human cells. However, the dynamics of RNA isoform changes upon cell-state-transitions during cell differentiation, the determinants and functional consequences have largely remained unclear. Here, we established an improved model for human neurogenesis in vitro that is amenable for systems-wide analyses of gene expression. Our multi-omics analysis reveals that the pronounced alterations in cell morphology correlate strongly with widespread changes in RNA isoform expression. Our approach identifies thousands of new RNA isoforms that are expressed at distinct differentiation stages. RNA isoforms mainly arise from exon skipping and the alternative usage of transcription start and polyadenylation sites during human neurogenesis. The transcript isoform changes can remodel the identity and functions of protein isoforms. Finally, our study identifies a set of RNA binding proteins as a potential determinant of differentiation stage-specific global isoform changes. This work supports the view of regulated isoform changes that underlie state-transitions during neurogenesis.
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Affiliation(s)
- Jelena Ulicevic
- Otto-Warburg-Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Zhihao Shao
- Otto-Warburg-Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
| | - Olga Jasnovidova
- Otto-Warburg-Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Annkatrin Bressin
- Otto-Warburg-Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Martyna Gajos
- Otto-Warburg-Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
| | - Alex Hm Ng
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, USA
| | - Siddharth Annaldasula
- Otto-Warburg-Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - David Meierhofer
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - George M Church
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, USA
| | - Volker Busskamp
- Department of Ophthalmology, University Hospital Bonn, Medical Faculty, Bonn, Germany
| | - Andreas Mayer
- Otto-Warburg-Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany.
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3
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Ciampi L, Serrano L, Irimia M. Unique transcriptomes of sensory and non-sensory neurons: insights from Splicing Regulatory States. Mol Syst Biol 2024; 20:296-310. [PMID: 38438733 PMCID: PMC10987577 DOI: 10.1038/s44320-024-00020-1] [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: 10/31/2023] [Revised: 01/04/2024] [Accepted: 01/12/2024] [Indexed: 03/06/2024] Open
Abstract
Alternative Splicing (AS) programs serve as instructive signals of cell type specificity, particularly within the brain, which comprises dozens of molecularly and functionally distinct cell types. Among them, retinal photoreceptors stand out due to their unique transcriptome, making them a particularly well-suited system for studying how AS shapes cell type-specific molecular functions. Here, we use the Splicing Regulatory State (SRS) as a novel framework to discuss the splicing factors governing the unique AS pattern of photoreceptors, and how this pattern may aid in the specification of their highly specialized sensory cilia. In addition, we discuss how other sensory cells with ciliated structures, for which data is much scarcer, also rely on specific SRSs to implement a proteome specialized in the detection of sensory stimuli. By reviewing the general rules of cell type- and tissue-specific AS programs, firstly in the brain and subsequently in specialized sensory neurons, we propose a novel paradigm on how SRSs are established and how they can diversify. Finally, we illustrate how SRSs shape the outcome of mutations in splicing factors to produce cell type-specific phenotypes that can lead to various human diseases.
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Affiliation(s)
- Ludovica Ciampi
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Luis Serrano
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra, Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - Manuel Irimia
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra, Barcelona, Spain.
- ICREA, Barcelona, Spain.
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4
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Jones EF, Haldar A, Oza VH, Lasseigne BN. Quantifying transcriptome diversity: a review. Brief Funct Genomics 2024; 23:83-94. [PMID: 37225889 DOI: 10.1093/bfgp/elad019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/14/2023] [Accepted: 05/05/2023] [Indexed: 05/26/2023] Open
Abstract
Following the central dogma of molecular biology, gene expression heterogeneity can aid in predicting and explaining the wide variety of protein products, functions and, ultimately, heterogeneity in phenotypes. There is currently overlapping terminology used to describe the types of diversity in gene expression profiles, and overlooking these nuances can misrepresent important biological information. Here, we describe transcriptome diversity as a measure of the heterogeneity in (1) the expression of all genes within a sample or a single gene across samples in a population (gene-level diversity) or (2) the isoform-specific expression of a given gene (isoform-level diversity). We first overview modulators and quantification of transcriptome diversity at the gene level. Then, we discuss the role alternative splicing plays in driving transcript isoform-level diversity and how it can be quantified. Additionally, we overview computational resources for calculating gene-level and isoform-level diversity for high-throughput sequencing data. Finally, we discuss future applications of transcriptome diversity. This review provides a comprehensive overview of how gene expression diversity arises, and how measuring it determines a more complete picture of heterogeneity across proteins, cells, tissues, organisms and species.
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Affiliation(s)
- Emma F Jones
- The Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Anisha Haldar
- The Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Vishal H Oza
- The Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brittany N Lasseigne
- The Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
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5
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Sinitcyn P, Richards AL, Weatheritt RJ, Brademan DR, Marx H, Shishkova E, Meyer JG, Hebert AS, Westphall MS, Blencowe BJ, Cox J, Coon JJ. Global detection of human variants and isoforms by deep proteome sequencing. Nat Biotechnol 2023; 41:1776-1786. [PMID: 36959352 PMCID: PMC10713452 DOI: 10.1038/s41587-023-01714-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 02/15/2023] [Indexed: 03/25/2023]
Abstract
An average shotgun proteomics experiment detects approximately 10,000 human proteins from a single sample. However, individual proteins are typically identified by peptide sequences representing a small fraction of their total amino acids. Hence, an average shotgun experiment fails to distinguish different protein variants and isoforms. Deeper proteome sequencing is therefore required for the global discovery of protein isoforms. Using six different human cell lines, six proteases, deep fractionation and three tandem mass spectrometry fragmentation methods, we identify a million unique peptides from 17,717 protein groups, with a median sequence coverage of approximately 80%. Direct comparison with RNA expression data provides evidence for the translation of most nonsynonymous variants. We have also hypothesized that undetected variants likely arise from mutation-induced protein instability. We further observe comparable detection rates for exon-exon junction peptides representing constitutive and alternative splicing events. Our dataset represents a resource for proteoform discovery and provides direct evidence that most frame-preserving alternatively spliced isoforms are translated.
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Affiliation(s)
- Pavel Sinitcyn
- Computational Systems Biochemistry Research Group, Max Planck Institute of Biochemistry, Martinsried, Germany
- Morgridge Institute for Research, Madison, WI, USA
| | - Alicia L Richards
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Robert J Weatheritt
- EMBL Australia and Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Dain R Brademan
- Morgridge Institute for Research, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Harald Marx
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Evgenia Shishkova
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Jesse G Meyer
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Alexander S Hebert
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael S Westphall
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Benjamin J Blencowe
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Jürgen Cox
- Computational Systems Biochemistry Research Group, Max Planck Institute of Biochemistry, Martinsried, Germany.
| | - Joshua J Coon
- Morgridge Institute for Research, Madison, WI, USA.
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
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6
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Kjer-Hansen P, Weatheritt RJ. The function of alternative splicing in the proteome: rewiring protein interactomes to put old functions into new contexts. Nat Struct Mol Biol 2023; 30:1844-1856. [PMID: 38036695 DOI: 10.1038/s41594-023-01155-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 10/17/2023] [Indexed: 12/02/2023]
Abstract
Alternative splicing affects more than 95% of multi-exon genes in the human genome. These changes affect the proteome in a myriad of ways. Here, we review our understanding of the breadth of these changes from their effect on protein structure to their influence on interactions. These changes encompass effects on nucleic acid binding in the nucleus to protein-carbohydrate interactions in the extracellular milieu, altering interactions involving all major classes of biological molecules. Protein isoforms have profound influences on cellular and tissue physiology, for example, by shaping neuronal connections, enhancing insulin secretion by pancreatic beta cells and allowing for alternative viral defense strategies in stem cells. More broadly, alternative splicing enables repurposing proteins from one context to another and thereby contributes to both the evolution of new traits as well as the creation of disease-specific interactomes that drive pathological phenotypes. In this Review, we highlight this universal character of alternative splicing as a central regulator of protein function with implications for almost every biological process.
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Affiliation(s)
- Peter Kjer-Hansen
- EMBL Australia, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.
- St. Vincent Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia.
| | - Robert J Weatheritt
- EMBL Australia, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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7
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Amaral P, Carbonell-Sala S, De La Vega FM, Faial T, Frankish A, Gingeras T, Guigo R, Harrow JL, Hatzigeorgiou AG, Johnson R, Murphy TD, Pertea M, Pruitt KD, Pujar S, Takahashi H, Ulitsky I, Varabyou A, Wells CA, Yandell M, Carninci P, Salzberg SL. The status of the human gene catalogue. Nature 2023; 622:41-47. [PMID: 37794265 PMCID: PMC10575709 DOI: 10.1038/s41586-023-06490-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/27/2023] [Indexed: 10/06/2023]
Abstract
Scientists have been trying to identify every gene in the human genome since the initial draft was published in 2001. In the years since, much progress has been made in identifying protein-coding genes, currently estimated to number fewer than 20,000, with an ever-expanding number of distinct protein-coding isoforms. Here we review the status of the human gene catalogue and the efforts to complete it in recent years. Beside the ongoing annotation of protein-coding genes, their isoforms and pseudogenes, the invention of high-throughput RNA sequencing and other technological breakthroughs have led to a rapid growth in the number of reported non-coding RNA genes. For most of these non-coding RNAs, the functional relevance is currently unclear; we look at recent advances that offer paths forward to identifying their functions and towards eventually completing the human gene catalogue. Finally, we examine the need for a universal annotation standard that includes all medically significant genes and maintains their relationships with different reference genomes for the use of the human gene catalogue in clinical settings.
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Affiliation(s)
- Paulo Amaral
- INSPER Institute of Education and Research, Sao Paulo, Brazil
| | | | - Francisco M De La Vega
- Department of Biomedical Data Science, Stanford University School of Medicine, Stanford, CA, USA
- Tempus Labs, Chicago, IL, USA
| | | | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK
| | - Thomas Gingeras
- Department of Functional Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Roderic Guigo
- Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Jennifer L Harrow
- Centre for Genomics Research, Discovery Sciences, AstraZeneca, Royston, UK
| | - Artemis G Hatzigeorgiou
- Department of Computer Science and Biomedical Informatics, Universithy of Thessaly, Lamia, Greece
- Hellenic Pasteur Institute, Athens, Greece
| | - Rory Johnson
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
- Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Dublin, Ireland
- Department of Medical Oncology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Terence D Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Mihaela Pertea
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Kim D Pruitt
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Shashikant Pujar
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Hazuki Takahashi
- Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Igor Ulitsky
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Ales Varabyou
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Christine A Wells
- Stem Cell Systems, Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Mark Yandell
- Departent of Human Genetics, Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Piero Carninci
- Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.
- Human Technopole, Milan, Italy.
| | - Steven L Salzberg
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA.
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA.
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD, USA.
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8
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Shirokikh NE, Jensen KB, Thakor N. Editorial: RNA machines. Front Genet 2023; 14:1290420. [PMID: 37829284 PMCID: PMC10565666 DOI: 10.3389/fgene.2023.1290420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023] Open
Affiliation(s)
- Nikolay E. Shirokikh
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Kirk Blomquist Jensen
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Nehal Thakor
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada
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9
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Engelhard CA, Khani S, Derdak S, Bilban M, Kornfeld JW. Nanopore sequencing unveils the complexity of the cold-activated murine brown adipose tissue transcriptome. iScience 2023; 26:107190. [PMID: 37564700 PMCID: PMC10410515 DOI: 10.1016/j.isci.2023.107190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/28/2023] [Accepted: 06/16/2023] [Indexed: 08/12/2023] Open
Abstract
Alternative transcription increases transcriptome complexity by expression of multiple transcripts per gene. Annotation and quantification of transcripts using short-read sequencing is non-trivial. Long-read sequencing aims at overcoming these problems by sequencing full-length transcripts. Activation of brown adipose tissue (BAT) thermogenesis involves major transcriptomic remodeling and positively affects metabolism via increased energy expenditure. We benchmark Oxford Nanopore Technology (ONT) long-read sequencing protocols to Illumina short-read sequencing assessing alignment characteristics, gene and transcript detection and quantification, differential gene and transcript expression, transcriptome reannotation, and differential transcript usage (DTU). We find ONT sequencing is superior to Illumina for transcriptome reassembly, reducing the risk of false-positive events by unambiguously mapping reads to transcripts. We identified novel isoforms of genes undergoing DTU in cold-activated BAT including Cars2, Adtrp, Acsl5, Scp2, Aldoa, and Pde4d, validated by real-time PCR. The reannotated murine BAT transcriptome established here provides a framework for future investigations into the regulation of BAT.
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Affiliation(s)
- Christoph Andreas Engelhard
- Department for Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Sajjad Khani
- Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sophia Derdak
- Core Facilities, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna, Austria
| | - Martin Bilban
- Department of Laboratory Medicine & Core Facilities, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Jan-Wilhelm Kornfeld
- Department for Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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10
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Jung H, Park HJ, Jo SH, Lee A, Lee HJ, Kim HS, Jung C, Cho HS. Nuclear OsFKBP20-1b maintains SR34 stability and promotes the splicing of retained introns upon ABA exposure in rice. THE NEW PHYTOLOGIST 2023; 238:2476-2494. [PMID: 36942934 DOI: 10.1111/nph.18892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/16/2023] [Indexed: 05/19/2023]
Abstract
Alternative splicing (AS) is a critical means by which plants respond to changes in the environment, but few splicing factors contributing to AS have been reported and functionally characterized in rice (Oryza sativa L.). Here, we explored the function and molecular mechanism of the spliceosome-associated protein OsFKBP20-1b during AS. We determined the AS landscape of wild-type and osfkbp20-1b knockout plants upon abscisic acid (ABA) treatment by transcriptome deep sequencing. To capture the dynamics of translating intron-containing mRNAs, we blocked transcription with cordycepin and performed polysome profiling. We also analyzed whether OsFKBP20-1b and the splicing factors OsSR34 and OsSR45 function together in AS using protoplast transfection assays. We show that OsFKBP20-1b interacts with OsSR34 and regulates its stability, suggesting a role as a chaperone-like protein in the spliceosome. OsFKBP20-1b facilitates the splicing of mRNAs with retained introns after ABA treatment; some of these mRNAs are translatable and encode functional transcriptional regulators of stress-responsive genes. In addition, interacting proteins, OsSR34 and OsSR45, regulate the splicing of the same retained introns as OsFKBP20-1b after ABA treatment. Our findings reveal that spliceosome-associated immunophilin functions in alternative RNA splicing in rice by positively regulating the splicing of retained introns to limit ABA response.
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Affiliation(s)
- Haemyeong Jung
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Hyun Ji Park
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
| | - Seung Hee Jo
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Areum Lee
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Hyo-Jun Lee
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, UST, Daejeon, 34113, South Korea
| | - Hyun-Soon Kim
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Choonkyun Jung
- Department of International Agricultural Technology and Crop Biotechnology Institute/Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, South Korea
- Department of Agriculture, Forestry, and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Hye Sun Cho
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
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11
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Kesner JS, Chen Z, Shi P, Aparicio AO, Murphy MR, Guo Y, Trehan A, Lipponen JE, Recinos Y, Myeku N, Wu X. Noncoding translation mitigation. Nature 2023; 617:395-402. [PMID: 37046090 PMCID: PMC10560126 DOI: 10.1038/s41586-023-05946-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 03/13/2023] [Indexed: 04/14/2023]
Abstract
Translation is pervasive outside of canonical coding regions, occurring in long noncoding RNAs, canonical untranslated regions and introns1-4, especially in ageing4-6, neurodegeneration5,7 and cancer8-10. Notably, the majority of tumour-specific antigens are results of noncoding translation11-13. Although the resulting polypeptides are often nonfunctional, translation of noncoding regions is nonetheless necessary for the birth of new coding sequences14,15. The mechanisms underlying the surveillance of translation in diverse noncoding regions and how escaped polypeptides evolve new functions remain unclear10,16-19. Functional polypeptides derived from annotated noncoding sequences often localize to membranes20,21. Here we integrate massively parallel analyses of more than 10,000 human genomic sequences and millions of random sequences with genome-wide CRISPR screens, accompanied by in-depth genetic and biochemical characterizations. Our results show that the intrinsic nucleotide bias in the noncoding genome and in the genetic code frequently results in polypeptides with a hydrophobic C-terminal tail, which is captured by the ribosome-associated BAG6 membrane protein triage complex for either proteasomal degradation or membrane targeting. By contrast, canonical proteins have evolved to deplete C-terminal hydrophobic residues. Our results reveal a fail-safe mechanism for the surveillance of unwanted translation from diverse noncoding regions and suggest a possible biochemical route for the preferential membrane localization of newly evolved proteins.
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Affiliation(s)
- Jordan S Kesner
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Ziheng Chen
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Peiguo Shi
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Alexis O Aparicio
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Michael R Murphy
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Yang Guo
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Aditi Trehan
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Jessica E Lipponen
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Yocelyn Recinos
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Natura Myeku
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Xuebing Wu
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA.
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12
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Rogalska ME, Vivori C, Valcárcel J. Regulation of pre-mRNA splicing: roles in physiology and disease, and therapeutic prospects. Nat Rev Genet 2023; 24:251-269. [PMID: 36526860 DOI: 10.1038/s41576-022-00556-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2022] [Indexed: 12/23/2022]
Abstract
The removal of introns from mRNA precursors and its regulation by alternative splicing are key for eukaryotic gene expression and cellular function, as evidenced by the numerous pathologies induced or modified by splicing alterations. Major recent advances have been made in understanding the structures and functions of the splicing machinery, in the description and classification of physiological and pathological isoforms and in the development of the first therapies for genetic diseases based on modulation of splicing. Here, we review this progress and discuss important remaining challenges, including predicting splice sites from genomic sequences, understanding the variety of molecular mechanisms and logic of splicing regulation, and harnessing this knowledge for probing gene function and disease aetiology and for the design of novel therapeutic approaches.
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Affiliation(s)
- Malgorzata Ewa Rogalska
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Claudia Vivori
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- The Francis Crick Institute, London, UK
| | - Juan Valcárcel
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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13
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Marasco LE, Kornblihtt AR. The physiology of alternative splicing. Nat Rev Mol Cell Biol 2023; 24:242-254. [PMID: 36229538 DOI: 10.1038/s41580-022-00545-z] [Citation(s) in RCA: 116] [Impact Index Per Article: 116.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2022] [Indexed: 11/09/2022]
Abstract
Alternative splicing is a substantial contributor to the high complexity of transcriptomes of multicellular eukaryotes. In this Review, we discuss the accumulated evidence that most of this complexity is reflected at the protein level and fundamentally shapes the physiology and pathology of organisms. This notion is supported not only by genome-wide analyses but, mainly, by detailed studies showing that global and gene-specific modulations of alternative splicing regulate highly diverse processes such as tissue-specific and species-specific cell differentiation, thermal regulation, neuron self-avoidance, infrared sensing, the Warburg effect, maintenance of telomere length, cancer and autism spectrum disorders (ASD). We also discuss how mastering the control of alternative splicing paved the way to clinically approved therapies for hereditary diseases.
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Affiliation(s)
- Luciano E Marasco
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Moleculary Celular and CONICET-UBA, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Alberto R Kornblihtt
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Moleculary Celular and CONICET-UBA, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina.
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14
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Amaral P, Carbonell-Sala S, De La Vega FM, Faial T, Frankish A, Gingeras T, Guigo R, Harrow JL, Hatzigeorgiou AG, Johnson R, Murphy TD, Pertea M, Pruitt KD, Pujar S, Takahashi H, Ulitsky I, Varabyou A, Wells CA, Yandell M, Carninci P, Salzberg SL. The status of the human gene catalogue. ARXIV 2023:arXiv:2303.13996v1. [PMID: 36994150 PMCID: PMC10055485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Scientists have been trying to identify all of the genes in the human genome since the initial draft of the genome was published in 2001. Over the intervening years, much progress has been made in identifying protein-coding genes, and the estimated number has shrunk to fewer than 20,000, although the number of distinct protein-coding isoforms has expanded dramatically. The invention of high-throughput RNA sequencing and other technological breakthroughs have led to an explosion in the number of reported non-coding RNA genes, although most of them do not yet have any known function. A combination of recent advances offers a path forward to identifying these functions and towards eventually completing the human gene catalogue. However, much work remains to be done before we have a universal annotation standard that includes all medically significant genes, maintains their relationships with different reference genomes, and describes clinically relevant genetic variants.
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Affiliation(s)
- Paulo Amaral
- INSPER Institute of Education and Research, São Paulo, SP, Brasil
| | - Silvia Carbonell-Sala
- Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003, Barcelona, Catalonia, Spain
| | - Francisco M. De La Vega
- Department of Biomedical Data Science, Stanford University School of Medicine, Stanford, CA; Tempus Labs, Inc., Chicago, IL
| | | | - Adam Frankish
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Thomas Gingeras
- Department of Functional Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
| | - Roderic Guigo
- Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003, Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Catalonia, Spain
| | - Jennifer L Harrow
- Centre for Genomics Research, Discovery Sciences, AstraZeneca, Da Vinci Building. Melbourn Science Park, Royston UK SG8 6HB
| | - Artemis G. Hatzigeorgiou
- Universithy of Thessaly, Department of Computer Science and Biomedical Informatics, Lamia, Greece; Hellenic Pasteur Institute, Athens, Greece
| | - Rory Johnson
- School of Biology and Environmental Science, University College Dublin, D04 V1W8 Dublin, Ireland; Conway Institute of Biomedical and Biomolecular Research, University College Dublin, D04 V1W8 Dublin, Ireland; Department of Medical Oncology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland; Department for BioMedical Research, University of Bern, 3008 Bern, Switzerland
| | - Terence D. Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Mihaela Pertea
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Kim D. Pruitt
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Shashikant Pujar
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Hazuki Takahashi
- Laboratory for Transcriptome Technology, RIKEN Center for Integrative Medical Sciences, Yokohama Kanagawa 230-0045 Japan
| | - Igor Ulitsky
- Department of Immunology and Regenerative Biology; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ales Varabyou
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Christine A. Wells
- Stem Cell Systems, Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville 3010 Vic Australia
| | - Mark Yandell
- Departent of Human Genetics, Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, USA
| | - Piero Carninci
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- Human Technopole, via Rita Levi Montalcini 1, Milan 20157 Italy
| | - Steven L. Salzberg
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
- Center for Computational Biology, Johns Hopkins University, Baltimore, MD, USA
- Department of Immunology and Regenerative Biology; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD, USA
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15
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Manuel JM, Guilloy N, Khatir I, Roucou X, Laurent B. Re-evaluating the impact of alternative RNA splicing on proteomic diversity. Front Genet 2023; 14:1089053. [PMID: 36845399 PMCID: PMC9947481 DOI: 10.3389/fgene.2023.1089053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/23/2023] [Indexed: 02/11/2023] Open
Abstract
Alternative splicing (AS) constitutes a mechanism by which protein-coding genes and long non-coding RNA (lncRNA) genes produce more than a single mature transcript. From plants to humans, AS is a powerful process that increases transcriptome complexity. Importantly, splice variants produced from AS can potentially encode for distinct protein isoforms which can lose or gain specific domains and, hence, differ in their functional properties. Advances in proteomics have shown that the proteome is indeed diverse due to the presence of numerous protein isoforms. For the past decades, with the help of advanced high-throughput technologies, numerous alternatively spliced transcripts have been identified. However, the low detection rate of protein isoforms in proteomic studies raised debatable questions on whether AS contributes to proteomic diversity and on how many AS events are really functional. We propose here to assess and discuss the impact of AS on proteomic complexity in the light of the technological progress, updated genome annotation, and current scientific knowledge.
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Affiliation(s)
- Jeru Manoj Manuel
- Research Center on Aging, Centre Intégré Universitaire de Santé et Services Sociaux de l’Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada,Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Noé Guilloy
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Inès Khatir
- Research Center on Aging, Centre Intégré Universitaire de Santé et Services Sociaux de l’Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada,Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Xavier Roucou
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada,Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke (CRCHUS), Sherbrooke, QC, Canada,Quebec Network for Research on Protein Function Structure and Engineering, PROTEO, Québec, QC, Canada
| | - Benoit Laurent
- Research Center on Aging, Centre Intégré Universitaire de Santé et Services Sociaux de l’Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada,Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada,*Correspondence: Benoit Laurent,
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16
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Shen Y, Li X, Wang D, Zhang L, Li X, Su L, Fan X, Yang X. COL3A1: Potential prognostic predictor for head and neck cancer based on immune-microenvironment alternative splicing. Cancer Med 2023; 12:4882-4894. [PMID: 36039012 PMCID: PMC9972170 DOI: 10.1002/cam4.5170] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/01/2022] [Accepted: 08/14/2022] [Indexed: 11/07/2022] Open
Abstract
We aimed to identify a novel prognostic biomarker for head and neck squamous cell carcinoma (HNSCC) based on tumor immunology-related alternative splicing (AS). Data for 502 HNSCC and 44 normal samples were obtained from the TCGA database and used to establish an AS-related risk model through univariate, least absolute shrinkage, and selection operator Cox regression analyses. Fresh HNSCC and normal oral tissues were surgically obtained from 44 HNSCC patients. Western blotting and quantitative reverse transcription-PCR were used to assess gene expression levels. Kaplan-Meier was performed to evaluate patients' overall survival (OS) rate. The CIBERSORT algorithm, single-sample gene set enrichment analysis, and immune checkpoint analyses were performed to compare immune activities between subgroups. The risk model was established using 10 pivotal AS events first. Collagen Type III Alpha 1 Chain (COL3A1) were screened based on |log2FC| ≥ 1 and FDR < 0.05 criteria. COL3A1 expression levels in HNSCC tissues were elevated relative to normal tissues (p < 0.001). Moreover, COL3A1 was a reliable biomarker for HNSCC patients' prognostic prediction in both cohorts (p < 0.001, p = 0.0085, respectively). COL3A1 protein (p = 0.0054) and mRNA (p < 0.0001) levels were correlated with HNSCC differentiation. Furthermore, the T stage was correlated with COL3A1 expression (p = 0.043), and COL3A1 expression was an independent prognostic predictor for HNSCC patients (p = 0.006). Compared with the risk model, COL3A1 was better at evaluating immune cell infiltrations, immune activities, and immune checkpoint gene expressions of HNSCC lesions.
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Affiliation(s)
- Yuchen Shen
- Vascular Anomaly Center, Department of Interventional Therapy, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of StomatologyNational Clinical Research Centre for Oral DiseasesShanghaiChina
| | - Xinyu Li
- Department of Neurosurgery, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Deming Wang
- Vascular Anomaly Center, Department of Interventional Therapy, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of StomatologyNational Clinical Research Centre for Oral DiseasesShanghaiChina
| | - Liming Zhang
- Vascular Anomaly Center, Department of Interventional Therapy, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of StomatologyNational Clinical Research Centre for Oral DiseasesShanghaiChina
| | - Xiao Li
- Vascular Anomaly Center, Department of Interventional Therapy, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of StomatologyNational Clinical Research Centre for Oral DiseasesShanghaiChina
| | - Lixin Su
- Vascular Anomaly Center, Department of Interventional Therapy, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of StomatologyNational Clinical Research Centre for Oral DiseasesShanghaiChina
| | - Xindong Fan
- Vascular Anomaly Center, Department of Interventional Therapy, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of StomatologyNational Clinical Research Centre for Oral DiseasesShanghaiChina
| | - Xitao Yang
- Vascular Anomaly Center, Department of Interventional Therapy, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of StomatologyNational Clinical Research Centre for Oral DiseasesShanghaiChina
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17
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Paukszto Ł, Wiśniewska J, Liszewska E, Majewska M, Jastrzębski J, Jankowski J, Ciereszko A, Słowińska M. Specific expression of alternatively spliced genes in the turkey (Meleagris gallopavo) reproductive tract revealed their function in spermatogenesis and post-testicular sperm maturation. Poult Sci 2023; 102:102484. [PMID: 36709584 PMCID: PMC9922982 DOI: 10.1016/j.psj.2023.102484] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023] Open
Abstract
The tissue-specific profile of alternatively spliced genes (ASGs) and their involvement in reproduction processes characteristic of turkey testis, epididymis, and ductus deferens were investigated for the first time in birds. Deep sequencing of male turkey reproductive tissue RNA samples (n = 6) was performed using Illumina RNA-Seq with 2 independent methods, rMATs and SUPPA2, for differential alternative splicing (DAS) event prediction. The expression of selected ASGs was validated using quantitative real-time reverse transcriptase-polymerase chain reaction. The testis was found to be the site of the highest number of posttranscriptional splicing events within the reproductive tract, and skipping exons were the most frequently occurring class of alternative splicing (AS) among the reproductive tract. Statistical analysis revealed 86, 229, and 6 DAS events in the testis/epididymis, testis/ductus deferens, and epididymis/ductus deferens comparison, respectively. Alternative splicing was found to be a mechanism of gene expression regulation within the turkey reproduction tract. In testis, modification was observed for spermatogenesis specific genes; the changes in 5' UTR could act as regulator of MEIG1 expression (a player during spermatocytes meiosis), and modification of 3' UTR led to diversification of CREM mRNA (modulator of gene expression related to the structuring of mature spermatozoa). Sperm tail formation can be regulated by changes in the 5' UTR of testicular SLC9A3R1 and gene silencing by producing dysfunctional variants of ODF2 in the testis and ATP1B3 in the epididymis. Predicted differentially ASGs in the turkey reproductive tract seem to be involved in the regulation of spermatogenesis, including acrosome formation and sperm tail formation and binding of sperm to the zona pellucida. Several ASGs were classified as cilia by actin and microtubule cytoskeleton organization. Such genes may play a role in the organization of sperm flagellum and post-testicular motility development. To our knowledge, this is the first functional investigation of alternatively spliced genes associated with tissue-specific processes in the turkey reproductive tract.
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Affiliation(s)
- Łukasz Paukszto
- Department of Botany and Nature Protection, Faculty of Biology and Biotechnology; University of Warmia and Mazury in Olsztyn, 10-719, Olsztyn, Poland
| | - Joanna Wiśniewska
- Department of Biological Function of Food, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland
| | - Ewa Liszewska
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland
| | - Marta Majewska
- Department of Human Physiology and Pathophysiology, School of Medicine, Collegium Medicum; University of Warmia and Mazury in Olsztyn, 10-561 Olsztyn, Poland
| | - Jan Jastrzębski
- Department of Plant Physiology, Genetics, and Biotechnology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719, Olsztyn, Poland
| | - Jan Jankowski
- Department of Poultry Science, University of Warmia and Mazury in Olsztyn, 10-719, Olsztyn, Poland
| | - Andrzej Ciereszko
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland
| | - Mariola Słowińska
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences in Olsztyn, 10-748, Olsztyn, Poland.
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18
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Winsky-Sommerer R, King HA, Iadevaia V, Möller-Levet C, Gerber AP. A post-transcriptional regulatory landscape of aging in the female mouse hippocampus. Front Aging Neurosci 2023; 15:1119873. [PMID: 37122377 PMCID: PMC10135431 DOI: 10.3389/fnagi.2023.1119873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/27/2023] [Indexed: 05/02/2023] Open
Abstract
Aging is associated with substantial physiological changes and constitutes a major risk factor for neurological disorders including dementia. Alterations in gene expression upon aging have been extensively studied; however, an in-depth characterization of post-transcriptional regulatory events remains elusive. Here, we profiled the age-related changes of the transcriptome and translatome in the female mouse hippocampus by RNA sequencing of total RNA and polysome preparations at four ages (3-, 6-, 12-, 20-month-old); and we implemented a variety of bioinformatics approaches to unravel alterations in transcript abundance, alternative splicing, and polyadenylation site selection. We observed mostly well-coordinated transcriptome and translatome expression signatures across age including upregulation of transcripts related to immune system processes and neuroinflammation, though transcripts encoding ribonucleoproteins or associated with mitochondrial functions, calcium signaling and the cell-cycle displayed substantial discordant profiles, suggesting translational control associated with age-related deficits in hippocampal-dependent behavior. By contrast, alternative splicing was less preserved, increased with age and was associated with distinct functionally-related transcripts encoding proteins acting at synapses/dendrites, RNA-binding proteins; thereby predicting regulatory roles for RBM3 and CIRBP. Only minor changes in polyadenylation site selection were identified, indicating pivotal 3'-end selection in young adults compared to older groups. Overall, our study provides a comprehensive resource of age-associated post-transcriptional regulatory events in the mouse hippocampus, enabling further examination of the molecular features underlying age-associated neurological diseases.
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19
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Zhang Y, Cai Q, Luo Y, Zhang Y, Li H. Integrated top-down and bottom-up proteomics mass spectrometry for the characterization of endogenous ribosomal protein heterogeneity. J Pharm Anal 2023; 13:63-72. [PMID: 36820077 PMCID: PMC9937802 DOI: 10.1016/j.jpha.2022.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Ribosomes are abundant, large RNA-protein complexes that are the sites of all protein synthesis in cells. Defects in ribosomal proteins (RPs), including proteoforms arising from genetic variations, alternative splicing of RNA transcripts, post-translational modifications and alterations of protein expression level, have been linked to a diverse range of diseases, including cancer and aging. Comprehensive characterization of ribosomal proteoforms is challenging but important for the discovery of potential disease biomarkers or protein targets. In the present work, using E. coli 70S RPs as an example, we first developed a top-down proteomics approach on a Waters Synapt G2 Si mass spectrometry (MS) system, and then applied it to the HeLa 80S ribosome. The results were complemented by a bottom-up approach. In total, 50 out of 55 RPs were identified using the top-down approach. Among these, more than 30 RPs were found to have their N-terminal methionine removed. Additional modifications such as methylation, acetylation, and hydroxylation were also observed, and the modification sites were identified by bottom-up MS. In a HeLa 80S ribosomal sample, we identified 98 ribosomal proteoforms, among which multiple truncated 80S ribosomal proteoforms were observed, the type of information which is often overlooked by bottom-up experiments. Although their relevance to diseases is not yet known, the integration of top-down and bottom-up proteomics approaches paves the way for the discovery of proteoform-specific disease biomarkers or targets.
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Affiliation(s)
- Ying Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Qinghua Cai
- Henan Engineering Laboratory for Mammary Bioreactor, School of Life Sciences, Henan University, Kaifeng, Henan, 475004, China
| | - Yuxiang Luo
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yu Zhang
- The Shennong Laboratory, Zhengzhou, 450002, China
| | - Huilin Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
- Corresponding author. School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
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20
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Li CX, Wang JS, Wang WN, Xu DK, Zhou YT, Sun FZ, Li YQ, Guo FZ, Ma JL, Zhang XY, Chang MJ, Xu BH, Ma F, Qian HL. Expression dynamics of periodic transcripts during cancer cell cycle progression and their correlation with anticancer drug sensitivity. Mil Med Res 2022; 9:71. [PMID: 36529792 PMCID: PMC9762028 DOI: 10.1186/s40779-022-00432-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 11/17/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms, among which transcriptional regulation is one of the most important components. Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle. However, the patterns of transcript isoform expression in the cell cycle are unclear. Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies, but none of them have been designed or evaluated at the alternative splicing transcript level. The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown, and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare. METHODS To explore alternative splicing patterns during cell cycle progression, we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines, using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples, and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle. Genomics of Drug Sensitivity in Cancer (GDSC) drug sensitivity datasets and Cancer Cell Line Encyclopedia (CCLE) transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity. We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients. Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6 (CDK4/6) inhibitors. Finally, alternative splicing transcripts associated with mitotic (M) phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis. RESULTS We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells. The results of the cell cycle assessment showed that 43,326, 41,578 and 29,244 transcripts were found to be periodically expressed in HeLa, HCT116 and MDA-MB-231 cells, respectively, among which 1280 transcripts showed this expression pattern in all three cancer cell lines. Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes. Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904. The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts. Combined with the cell cycle-related drug screening, the results also showed that a set of periodic transcripts, for example, ENST00000314392 (a dolichyl-phosphate mannosyltransferase polypeptide 2 isoform transcript), was more associated with drug sensitivity than the levels of their corresponding gene transcripts. CONCLUSIONS In summary, we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity, providing novel insights into alternative splicing-related drug development and evaluation.
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Affiliation(s)
- Chun-Xiao Li
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.,Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Jin-Song Wang
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Wen-Na Wang
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Dong-Kui Xu
- Department of VIP, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Yan-Tong Zhou
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Fang-Zhou Sun
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Yi-Qun Li
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Feng-Zhu Guo
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Jia-Lu Ma
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Xue-Yan Zhang
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Meng-Jiao Chang
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Bing-He Xu
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. .,Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| | - Fei Ma
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China. .,Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| | - Hai-Li Qian
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
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21
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Holguin-Cruz JA, Foster LJ, Gsponer J. Where protein structure and cell diversity meet. Trends Cell Biol 2022; 32:996-1007. [PMID: 35537902 DOI: 10.1016/j.tcb.2022.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 01/21/2023]
Abstract
Protein-protein interaction networks - interactomes - are charted with the hope to understand how phenotypes emerge and how they are altered in disease states. Early efforts to map interactomes have focused on the assembly of context agnostic, reference networks. However, recent studies have mapped interactomes across different cell lines and tissues, finding highly variable interactomes due to the rewiring of protein-protein interactions in different contexts. Increasing evidence points to significant links between protein structure and interactome diversity seen across cell types and tissues. We discuss how recent findings support the key role of alternative splicing and phosphorylation, two well-established regulators of protein structural and functional diversity, in defining cell type- and tissue-specific interactomes. Moreover, we show that intrinsically disordered protein regions are most favorably equipped to support interactome rewiring by acting as hubs of protein structure and function regulation.
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Affiliation(s)
- Jorge A Holguin-Cruz
- Michael Smith Laboratories, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - Leonard J Foster
- Michael Smith Laboratories, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - Jörg Gsponer
- Michael Smith Laboratories, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada.
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22
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Xiao J, Wang WX. Patterns and Crucial Regulation of Alternative Splicing During Early Development in Zebrafish. J Mol Biol 2022; 434:167821. [PMID: 36087778 DOI: 10.1016/j.jmb.2022.167821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/30/2022] [Accepted: 08/30/2022] [Indexed: 10/31/2022]
Abstract
Many vertebrate genes generate multiple transcript variants that may encode functionally distinct protein isoforms, but the transcriptomes of various developmental stages are poorly defined. Identifying the transcriptome and its regulation during the normal developmental process is the key to deciphering the developmental stage-specific functions of genes. Here we presented a systematic assessment of the temporal alternative splicing (AS) events during the critical development stages to capture the dynamic gene expression changes and AS in zebrafish. An unexpected transcriptome complexity generated by AS was observed during zebrafish development. The patterns of AS events varied substantially among developmental stages despite the similarities in the total proportion of AS genes. We further found that AS afforded substantial functional diversification of genes through the generation of stage-specific AS events from broadly protein-coding genes as an essential developmental regulatory mechanism. Skipped exon (SE) showed the strongest signals among developmental AS (devAS), suggesting that devAS events generated by SE may be necessary for the normal development of zebrafish. Most developmental genes regulated by AS mechanisms were not modulated in terms of their overall expression levels, indicating that AS shaped the transcriptome independently from transcriptional regulation during development. 128-cell stage was a critical stage for gene transcription during embryonic development. Splicing factors as an essential developmental regulator underwent AS in the potential autoregulatory feedback loop and expressed multiple isoforms. Thus, zebrafish development was shaped by an interplay of programs controlling gene expression levels and AS. Overall, we provided a global view of developmental patterns of AS during zebrafish development and revealed that AS transitions were the crucial regulatory component of zebrafish embryonic development.
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Affiliation(s)
- Jie Xiao
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Wen-Xiong Wang
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China.
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23
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Fisher E, Feng J. RNA splicing regulators play critical roles in neurogenesis. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1728. [PMID: 35388651 DOI: 10.1002/wrna.1728] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
Alternative RNA splicing increases transcript diversity in different cell types and under varying conditions. It is executed with the help of RNA splicing regulators (RSRs), which are operationally defined as RNA-binding proteins (RBPs) that regulate alternative splicing, but not directly catalyzing the chemical reactions of splicing. By systematically searching for RBPs and manually identifying those that regulate splicing, we curated 305 RSRs in the human genome. Surprisingly, most of the RSRs are involved in neurogenesis. Among these RSRs, we focus on nine families (PTBP, NOVA, RBFOX, ELAVL, CELF, DBHS, MSI, PCBP, and MBNL) that play essential roles in the neurogenic pathway. A better understanding of their functions will provide novel insights into the role of splicing in brain development, health, and disease. This comprehensive review serves as a stepping-stone to explore the diverse and complex set of RSRs as fundamental regulators of neural development. This article is categorized under: RNA-Based Catalysis > RNA Catalysis in Splicing and Translation RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Emily Fisher
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York, USA
- Veterans Affairs Western New York Healthcare System, Buffalo, New York, USA
| | - Jian Feng
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York, USA
- Veterans Affairs Western New York Healthcare System, Buffalo, New York, USA
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24
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Lelong EIJ, Khelifi G, Adjibade P, Joncas FH, Grenier St-Sauveur V, Paquette V, Gris T, Zoubeidi A, Audet-Walsh E, Lambert JP, Toren P, Mazroui R, Hussein SMI. Prostate cancer resistance leads to a global deregulation of translation factors and unconventional translation. NAR Cancer 2022; 4:zcac034. [PMID: 36348939 PMCID: PMC9634437 DOI: 10.1093/narcan/zcac034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/29/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Emerging evidence associates translation factors and regulators to tumorigenesis. However, our understanding of translational changes in cancer resistance is still limited. Here, we generated an enzalutamide-resistant prostate cancer (PCa) model, which recapitulated key features of clinical enzalutamide-resistant PCa. Using this model and poly(ribo)some profiling, we investigated global translation changes that occur during acquisition of PCa resistance. We found that enzalutamide-resistant cells exhibit an overall decrease in mRNA translation with a specific deregulation in the abundance of proteins involved in mitochondrial processes and in translational regulation. However, several mRNAs escape this translational downregulation and are nonetheless bound to heavy polysomes in enzalutamide-resistant cells suggesting active translation. Moreover, expressing these corresponding genes in enzalutamide-sensitive cells promotes resistance to enzalutamide treatment. We also found increased association of long non-coding RNAs (lncRNAs) with heavy polysomes in enzalutamide-resistant cells, suggesting that some lncRNAs are actively translated during enzalutamide resistance. Consistent with these findings, expressing the predicted coding sequences of known lncRNAs JPX, CRNDE and LINC00467 in enzalutamide-sensitive cells drove resistance to enzalutamide. Taken together, this suggests that aberrant translation of specific mRNAs and lncRNAs is a strong indicator of PCa enzalutamide resistance, which points towards novel therapeutic avenues that may target enzalutamide-resistant PCa.
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Affiliation(s)
- Emeline I J Lelong
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - Gabriel Khelifi
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - Pauline Adjibade
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - France-Hélène Joncas
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - Valérie Grenier St-Sauveur
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - Virginie Paquette
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Endocrinology and Nephrology Division , Quebec City, Québec G1V 4G2, Canada
| | - Typhaine Gris
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - Amina Zoubeidi
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia , Vancouver, British Columbia V6H 3Z6, Canada
| | - Etienne Audet-Walsh
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Endocrinology and Nephrology Division , Quebec City, Québec G1V 4G2, Canada
| | - Jean-Philippe Lambert
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Endocrinology and Nephrology Division , Quebec City, Québec G1V 4G2, Canada
| | - Paul Toren
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - Rachid Mazroui
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
| | - Samer M I Hussein
- Cancer Research Center, Université Laval , Quebec City, Québec G1R 3S3, Canada
- CHU of Québec-Université Laval Research Center, Oncology Division , Quebec City, Québec G1R 3S3, Canada
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25
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Cacioppo R, Lindon C. Regulating the regulator: a survey of mechanisms from transcription to translation controlling expression of mammalian cell cycle kinase Aurora A. Open Biol 2022; 12:220134. [PMID: 36067794 PMCID: PMC9448500 DOI: 10.1098/rsob.220134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aurora Kinase A (AURKA) is a positive regulator of mitosis with a strict cell cycle-dependent expression pattern. Recently, novel oncogenic roles of AURKA have been uncovered that are independent of the kinase activity and act within multiple signalling pathways, including cell proliferation, survival and cancer stem cell phenotypes. For this, cellular abundance of AURKA protein is per se crucial and must be tightly fine-tuned. Indeed, AURKA is found overexpressed in different cancers, typically as a result of gene amplification or enhanced transcription. It has however become clear that impaired processing, decay and translation of AURKA mRNA can also offer the basis for altered AURKA levels. Accordingly, the involvement of gene expression mechanisms controlling AURKA expression in human diseases is increasingly recognized and calls for much more research. Here, we explore and create an integrated view of the molecular processes regulating AURKA expression at the level of transcription, post-transcription and translation, intercalating discussion on how impaired regulation underlies disease. Given that targeting AURKA levels might affect more functions compared to inhibiting the kinase activity, deeper understanding of its gene expression may aid the design of alternative and therapeutically more successful ways of suppressing the AURKA oncogene.
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Affiliation(s)
- Roberta Cacioppo
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, UK
| | - Catherine Lindon
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, UK
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26
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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: 111] [Impact Index Per Article: 55.5] [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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27
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Tian S, Monteiro A. A transcriptomic atlas underlying developmental plasticity of seasonal forms of Bicyclus anynana butterflies. Mol Biol Evol 2022; 39:msac126. [PMID: 35679434 PMCID: PMC9218548 DOI: 10.1093/molbev/msac126] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/10/2022] [Accepted: 05/31/2022] [Indexed: 11/12/2022] Open
Abstract
Organisms residing in regions with alternating seasons often develop different phenotypes, or forms, in each season. These forms are often adaptations to each season and result from an altered developmental response to specific environmental cues such as temperature. While multiple studies have examined form-specific gene expression profiles in a diversity of species, little is known about how environments and developmental transitions, cued by hormone pulses, alter post-transcriptional patterns. In this study, we examine how gene expression, alternative splicing, and miRNA-mediated gene silencing in Bicyclus anynana butterfly hindwing tissue, varies across two rearing temperatures at four developmental timepoints. These timepoints flank two temperature-sensitive periods that coincide with two pulses of the insect hormone 20E. Our results suggest that developmental transitions, coincident with 20E pulses, elicit a greater impact on all these transcriptomic patterns than rearing temperatures per se. More similar transcriptomic patterns are observed pre-20E pulses than those observed post-20E pulses. We also found functionally distinct sets of differentially expressed and differentially spliced genes in the seasonal forms. Furthermore, around 10% of differentially expressed genes are predicted to be direct targets of, and regulated by, differentially expressed miRNAs between the seasonal forms. Many differentially expressed genes, miRNAs, or differentially spliced genes potentially regulate eyespot size plasticity, and we validated the differential splicing pattern of one such gene, daughterless. We present a comprehensive and interactive transcriptomic atlas of the hindwing tissue of both seasonal forms of B. anynana throughout development, a model organism of seasonal plasticity.
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Affiliation(s)
- Shen Tian
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Antónia Monteiro
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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28
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Wang X, Hua J, Li J, Zhang J, Dzakah EE, Cao G, Lin W. Mechanisms of non-coding RNA-modulated alternative splicing in cancer. RNA Biol 2022; 19:541-547. [PMID: 35427215 PMCID: PMC9037454 DOI: 10.1080/15476286.2022.2062846] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Alternative splicing (AS) is a common and pivotal process for eukaryotic gene expression regulation, which enables a precursor RNA to produce multiple transcript variants with diverse cellular functions. Aberrant AS represents a hallmark of cancer, engaged in all stages of tumorigenesis from initiation to metastasis. Accumulating pieces of evidence have revealed the involvement of non-coding RNAs (ncRNAs) in regulating AS in human cancers. In this review, we overview the underlying mechanisms of non-coding RNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) modulated AS at diverse levels in human cancers, and summarize their regulatory functions in tumorigenesis.
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Affiliation(s)
- Xiaolin Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science (Hips), Chinese Academy of Sciences, Hefei, Anhui, P. R. China
- University of Science and Technology of China, Hefei, Anhui, P. R. China
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, HIPS, Chinese Academy of Sciences, Hefei, Anhui, P. R. China
- High Magnetic Field Laboratory of Anhui Province, Hefei, Anhui, P. R. China
| | - Jinghan Hua
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science (Hips), Chinese Academy of Sciences, Hefei, Anhui, P. R. China
- University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Jingxin Li
- University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Jiahui Zhang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science (Hips), Chinese Academy of Sciences, Hefei, Anhui, P. R. China
- University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Emmanuel Enoch Dzakah
- Department of Molecular Biology and Biotechnology, School of Biological Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Guozhen Cao
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science (Hips), Chinese Academy of Sciences, Hefei, Anhui, P. R. China
- University of Science and Technology of China, Hefei, Anhui, P. R. China
| | - Wenchu Lin
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science (Hips), Chinese Academy of Sciences, Hefei, Anhui, P. R. China
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, HIPS, Chinese Academy of Sciences, Hefei, Anhui, P. R. China
- High Magnetic Field Laboratory of Anhui Province, Hefei, Anhui, P. R. China
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29
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Miller RM, Jordan BT, Mehlferber MM, Jeffery ED, Chatzipantsiou C, Kaur S, Millikin RJ, Dai Y, Tiberi S, Castaldi PJ, Shortreed MR, Luckey CJ, Conesa A, Smith LM, Deslattes Mays A, Sheynkman GM. Enhanced protein isoform characterization through long-read proteogenomics. Genome Biol 2022; 23:69. [PMID: 35241129 PMCID: PMC8892804 DOI: 10.1186/s13059-022-02624-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 02/02/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The detection of physiologically relevant protein isoforms encoded by the human genome is critical to biomedicine. Mass spectrometry (MS)-based proteomics is the preeminent method for protein detection, but isoform-resolved proteomic analysis relies on accurate reference databases that match the sample; neither a subset nor a superset database is ideal. Long-read RNA sequencing (e.g., PacBio or Oxford Nanopore) provides full-length transcripts which can be used to predict full-length protein isoforms. RESULTS We describe here a long-read proteogenomics approach for integrating sample-matched long-read RNA-seq and MS-based proteomics data to enhance isoform characterization. We introduce a classification scheme for protein isoforms, discover novel protein isoforms, and present the first protein inference algorithm for the direct incorporation of long-read transcriptome data to enable detection of protein isoforms previously intractable to MS-based detection. We have released an open-source Nextflow pipeline that integrates long-read sequencing in a proteomic workflow for isoform-resolved analysis. CONCLUSIONS Our work suggests that the incorporation of long-read sequencing and proteomic data can facilitate improved characterization of human protein isoform diversity. Our first-generation pipeline provides a strong foundation for future development of long-read proteogenomics and its adoption for both basic and translational research.
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Affiliation(s)
- Rachel M. Miller
- grid.14003.360000 0001 2167 3675Department of Chemistry, University of Wisconsin-Madison, Madison, WI USA
| | - Ben T. Jordan
- grid.27755.320000 0000 9136 933XDepartment of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA USA
| | - Madison M. Mehlferber
- grid.27755.320000 0000 9136 933XDepartment of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XDepartment of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA USA
| | - Erin D. Jeffery
- grid.27755.320000 0000 9136 933XDepartment of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA USA
| | | | - Simi Kaur
- grid.14003.360000 0001 2167 3675Department of Chemistry, University of Wisconsin-Madison, Madison, WI USA
| | - Robert J. Millikin
- grid.14003.360000 0001 2167 3675Department of Chemistry, University of Wisconsin-Madison, Madison, WI USA
| | - Yunxiang Dai
- grid.14003.360000 0001 2167 3675Department of Chemistry, University of Wisconsin-Madison, Madison, WI USA
| | - Simone Tiberi
- grid.7400.30000 0004 1937 0650Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Swiss Institute of Bioinformatics, University of Zurich, Zurich, Switzerland
| | - Peter J. Castaldi
- grid.62560.370000 0004 0378 8294Channing Division of Network Medicine, Brigham and Women’s Hospital, Boston, MA USA ,grid.62560.370000 0004 0378 8294Division of General Medicine and Primary Care, Brigham and Women’s Hospital, Boston, MA USA
| | - Michael R. Shortreed
- grid.14003.360000 0001 2167 3675Department of Chemistry, University of Wisconsin-Madison, Madison, WI USA
| | - Chance John Luckey
- grid.27755.320000 0000 9136 933XDepartment of Pathology, University of Virginia, Charlottesville, VA USA
| | - Ana Conesa
- grid.4711.30000 0001 2183 4846Institute for Integrative Systems Biology, Spanish National Research Council (CSIC), Paterna, Spain ,grid.15276.370000 0004 1936 8091Microbiology and Cell Science Department, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL USA
| | - Lloyd M. Smith
- grid.14003.360000 0001 2167 3675Department of Chemistry, University of Wisconsin-Madison, Madison, WI USA
| | - Anne Deslattes Mays
- grid.420089.70000 0000 9635 8082 Office of Data Science and Sharing, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD USA
| | - Gloria M. Sheynkman
- grid.27755.320000 0000 9136 933XDepartment of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XCenter for Public Health Genomics, University of Virginia, Charlottesville, VA USA ,grid.27755.320000 0000 9136 933XUVA Cancer Center, University of Virginia, Charlottesville, VA USA
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30
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Reixachs-Solé M, Eyras E. Uncovering the impacts of alternative splicing on the proteome with current omics techniques. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1707. [PMID: 34979593 PMCID: PMC9542554 DOI: 10.1002/wrna.1707] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 12/15/2022]
Abstract
The high‐throughput sequencing of cellular RNAs has underscored a broad effect of isoform diversification through alternative splicing on the transcriptome. Moreover, the differential production of transcript isoforms from gene loci has been recognized as a critical mechanism in cell differentiation, organismal development, and disease. Yet, the extent of the impact of alternative splicing on protein production and cellular function remains a matter of debate. Multiple experimental and computational approaches have been developed in recent years to address this question. These studies have unveiled how molecular changes at different steps in the RNA processing pathway can lead to differences in protein production and have functional effects. New and emerging experimental technologies open exciting new opportunities to develop new methods to fully establish the connection between messenger RNA expression and protein production and to further investigate how RNA variation impacts the proteome and cell function. This article is categorized under:RNA Processing > Splicing Regulation/Alternative Splicing Translation > Regulation RNA Evolution and Genomics > Computational Analyses of RNA
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Affiliation(s)
- Marina Reixachs-Solé
- The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia.,EMBL Australia Partner Laboratory Network and the Australian National University, Canberra, Australian Capital Territory, Australia
| | - Eduardo Eyras
- The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia.,EMBL Australia Partner Laboratory Network and the Australian National University, Canberra, Australian Capital Territory, Australia.,Catalan Institution for Research and Advanced Studies, Barcelona, Spain.,Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
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31
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Gohr A, Mantica F, Hermoso-Pulido A, Tapial J, Márquez Y, Irimia M. Computational Analysis of Alternative Splicing Using VAST-TOOLS and the VastDB Framework. Methods Mol Biol 2022; 2537:97-128. [PMID: 35895261 DOI: 10.1007/978-1-0716-2521-7_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Alternative splicing (AS) can vastly expand animal transcriptomes and proteomes. Two main open questions in the field are how AS is regulated across cell/tissue types and disease, and what roles different AS events play. To facilitate AS research, we have created the computational VastDB framework, which comprises a series of complementary software and resources that we describe in this chapter. The VastDB framework is especially designed to aid biomedical researchers without a strong computational background. It offers tools and resources to: (a) quantify AS and identify differentially spliced AS events using RNA-seq data (vast-tools), (b) perform multiple genomic and sequence analyses for investigating AS events (Matt), (c) identify AS events with genomic and regulatory conservation among species (ExOrthist), and (d) help with the biological interpretation of the results, and, ultimately, with the identification of interesting AS events to design wet-lab experiments (VastDB and PastDB).
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Affiliation(s)
- André Gohr
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Federica Mantica
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Antonio Hermoso-Pulido
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Javier Tapial
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Yamile Márquez
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Manuel Irimia
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra, Barcelona, Spain.
- ICREA, Barcelona, Spain.
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32
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Kashkan I, Timofeyenko K, Růžička K. How alternative splicing changes the properties of plant proteins. QUANTITATIVE PLANT BIOLOGY 2022; 3:e14. [PMID: 37077961 PMCID: PMC10095807 DOI: 10.1017/qpb.2022.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 05/01/2022] [Accepted: 05/03/2022] [Indexed: 05/03/2023]
Abstract
Most plant primary transcripts undergo alternative splicing (AS), and its impact on protein diversity is a subject of intensive investigation. Several studies have uncovered various mechanisms of how particular protein splice isoforms operate. However, the common principles behind the AS effects on protein function in plants have rarely been surveyed. Here, on the selected examples, we highlight diverse tissue expression patterns, subcellular localization, enzymatic activities, abilities to bind other molecules and other relevant features. We describe how the protein isoforms mutually interact to underline their intriguing roles in altering the functionality of protein complexes. Moreover, we also discuss the known cases when these interactions have been placed inside the autoregulatory loops. This review is particularly intended for plant cell and developmental biologists who would like to gain inspiration on how the splice variants encoded by their genes of interest may coordinately work.
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Affiliation(s)
- Ivan Kashkan
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czech Republic
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno62500, Czech Republic
| | - Ksenia Timofeyenko
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czech Republic
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno62500, Czech Republic
| | - Kamil Růžička
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czech Republic
- Author for correspondence: K. Růžička, E-mail:
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33
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Di Bartolomei G, Scheiffele P. An Optimized Protocol for the Mapping of Cell Type-Specific Ribosome-Associated Transcript Isoforms from Small Mouse Brain Regions. Methods Mol Biol 2022; 2537:37-49. [PMID: 35895257 DOI: 10.1007/978-1-0716-2521-7_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Over the past years, technological advances in transcriptomics provided deep insights into gene expression programs and their role in tissue organization and cellular functions. The isolation of ribosome-associated transcripts is a powerful approach for deep profiling of cell type-specific transcripts, and particularly well-suited for quantitative analysis of transcript isoforms. This method employs conditional ribosome epitope-tagging in genetically defined cell types, followed by affinity-isolation of ribosome-associated mRNAs. Advantages of this approach are twofold: first, the method enables rapid retrieval of mRNAs without tissue dissociation and cell sorting steps. Second, capturing of ribosome-associated mRNAs, enriches for transcripts recruited for active translation, therefore providing an approximation to the cellular translatome. Here, we describe one application of this method for the identification of the transcriptome of excitatory neuronal cells (mitral and tufted cells) of the mouse olfactory bulb, through RiboTag isolation from the vGlut2-IRES-cre mouse line as genetic driver of endogenously tagged ribosome expression.
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34
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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: 13] [Impact Index Per Article: 6.5] [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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35
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Qi X, Gu H, Qu L. Transcriptome-Wide Analyses Identify Dominant as the Predominantly Non-Conservative Alternative Splicing Inheritance Patterns in F1 Chickens. Front Genet 2021; 12:774240. [PMID: 34925458 PMCID: PMC8678468 DOI: 10.3389/fgene.2021.774240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 11/05/2021] [Indexed: 11/25/2022] Open
Abstract
Transcriptome analysis has been used to investigate many economically traits in chickens; however, alternative splicing still lacks a systematic method of study that is able to promote proteome diversity, and fine-tune expression dynamics. Hybridization has been widely utilized in chicken breeding due to the resulting heterosis, but the dynamic changes in alternative splicing during this process are significant yet unclear. In this study, we performed a reciprocal crossing experiment involving the White Leghorn and Cornish Game chicken breeds which exhibit major differences in body size and reproductive traits, and conducted RNA sequencing of the brain, muscle, and liver tissues to identify the inheritance patterns. A total of 40 515 and 42 612 events were respectively detected in the brain and muscle tissues, with 39 843 observed in the liver; 2807, 4242, and 4538 events significantly different between two breeds were identified in the brain, muscle, and liver tissues, respectively. The hierarchical cluster of tissues from different tissues from all crosses, based on the alternative splicing profiles, suggests high tissue and strain specificity. Furthermore, a comparison between parental strains and hybrid crosses indicated that over one third of alternative splicing genes showed conserved patterns in all three tissues, while the second prevalent pattern was non-additive, which included both dominant and transgressive patterns; this meant that the dominant pattern plays a more important role than suppression. Our study provides an overview of the inheritance patterns of alternative splicing in layer and broiler chickens, to better understand post-transcriptional regulation during hybridization.
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Affiliation(s)
- Xin Qi
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Hongchang Gu
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Lujiang Qu
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
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36
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Kumari A, Sedehizadeh S, Brook JD, Kozlowski P, Wojciechowska M. Differential fates of introns in gene expression due to global alternative splicing. Hum Genet 2021; 141:31-47. [PMID: 34907472 PMCID: PMC8758631 DOI: 10.1007/s00439-021-02409-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 12/02/2021] [Indexed: 02/06/2023]
Abstract
The discovery of introns over four decades ago revealed a new vision of genes and their interrupted arrangement. Throughout the years, it has appeared that introns play essential roles in the regulation of gene expression. Unique processing of excised introns through the formation of lariats suggests a widespread role for these molecules in the structure and function of cells. In addition to rapid destruction, these lariats may linger on in the nucleus or may even be exported to the cytoplasm, where they remain stable circular RNAs (circRNAs). Alternative splicing (AS) is a source of diversity in mature transcripts harboring retained introns (RI-mRNAs). Such RNAs may contain one or more entire retained intron(s) (RIs), but they may also have intron fragments resulting from sequential excision of smaller subfragments via recursive splicing (RS), which is characteristic of long introns. There are many potential fates of RI-mRNAs, including their downregulation via nuclear and cytoplasmic surveillance systems and the generation of new protein isoforms with potentially different functions. Various reports have linked the presence of such unprocessed transcripts in mammals to important roles in normal development and in disease-related conditions. In certain human neurological-neuromuscular disorders, including myotonic dystrophy type 2 (DM2), frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS) and Duchenne muscular dystrophy (DMD), peculiar processing of long introns has been identified and is associated with their pathogenic effects. In this review, we discuss different mechanisms involved in the processing of introns during AS and the functions of these large sections of the genome in our biology.
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Affiliation(s)
- Anjani Kumari
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Saam Sedehizadeh
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - John David Brook
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Piotr Kozlowski
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland
| | - Marzena Wojciechowska
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland. .,Department of Rare Human Diseases, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland.
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37
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Comparative ribosome profiling reveals distinct translational landscapes of salt-sensitive and -tolerant rice. BMC Genomics 2021; 22:612. [PMID: 34384368 PMCID: PMC8359061 DOI: 10.1186/s12864-021-07922-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 08/03/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Soil salinization represents a serious threat to global rice production. Although significant research has been conducted to understand salt stress at the genomic, transcriptomic and proteomic levels, few studies have focused on the translatomic responses to this stress. Recent studies have suggested that transcriptional and translational responses to salt stress can often operate independently. RESULTS We sequenced RNA and ribosome-protected fragments (RPFs) from the salt-sensitive rice (O. sativa L.) cultivar 'Nipponbare' (NB) and the salt-tolerant cultivar 'Sea Rice 86' (SR86) under normal and salt stress conditions. A large discordance between salt-induced transcriptomic and translatomic alterations was found in both cultivars, with more translationally regulated genes being observed in SR86 in comparison to NB. A biased ribosome occupancy, wherein RPF depth gradually increased from the 5' ends to the 3' ends of coding regions, was revealed in NB and SR86. This pattern was strengthened by salt stress, particularly in SR86. On the contrary, the strength of ribosome stalling was accelerated in salt-stressed NB but decreased in SR86. CONCLUSIONS This study revealed that translational reprogramming represents an important layer of salt stress responses in rice, and the salt-tolerant cultivar SR86 adopts a more flexible translationally adaptive strategy to cope with salt stress compared to the salt susceptible cultivar NB. The differences in translational dynamics between NB and SR86 may derive from their differing levels of ribosome stalling under salt stress.
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38
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Blake D, Lynch KW. The three as: Alternative splicing, alternative polyadenylation and their impact on apoptosis in immune function. Immunol Rev 2021; 304:30-50. [PMID: 34368964 DOI: 10.1111/imr.13018] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/19/2021] [Accepted: 07/28/2021] [Indexed: 12/13/2022]
Abstract
The latest advances in next-generation sequencing studies and transcriptomic profiling over the past decade have highlighted a surprising frequency of genes regulated by RNA processing mechanisms in the immune system. In particular, two control steps in mRNA maturation, namely alternative splicing and alternative polyadenylation, are now recognized to occur in the vast majority of human genes. Both have the potential to alter the identity of the encoded protein, as well as control protein abundance or even protein localization or association with other factors. In this review, we will provide a summary of the general mechanisms by which alternative splicing (AS) and alternative polyadenylation (APA) occur, their regulation within cells of the immune system, and their impact on immunobiology. In particular, we will focus on how control of apoptosis by AS and APA is used to tune cell fate during an immune response.
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Affiliation(s)
- Davia Blake
- Immunology Graduate Group and the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kristen W Lynch
- Immunology Graduate Group and the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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39
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De Paoli-Iseppi R, Gleeson J, Clark MB. Isoform Age - Splice Isoform Profiling Using Long-Read Technologies. Front Mol Biosci 2021; 8:711733. [PMID: 34409069 PMCID: PMC8364947 DOI: 10.3389/fmolb.2021.711733] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/19/2021] [Indexed: 01/12/2023] Open
Abstract
Alternative splicing (AS) of RNA is a key mechanism that results in the expression of multiple transcript isoforms from single genes and leads to an increase in the complexity of both the transcriptome and proteome. Regulation of AS is critical for the correct functioning of many biological pathways, while disruption of AS can be directly pathogenic in diseases such as cancer or cause risk for complex disorders. Current short-read sequencing technologies achieve high read depth but are limited in their ability to resolve complex isoforms. In this review we examine how long-read sequencing (LRS) technologies can address this challenge by covering the entire RNA sequence in a single read and thereby distinguish isoform changes that could impact RNA regulation or protein function. Coupling LRS with technologies such as single cell sequencing, targeted sequencing and spatial transcriptomics is producing a rapidly expanding suite of technological approaches to profile alternative splicing at the isoform level with unprecedented detail. In addition, integrating LRS with genotype now allows the impact of genetic variation on isoform expression to be determined. Recent results demonstrate the potential of these techniques to elucidate the landscape of splicing, including in tissues such as the brain where AS is particularly prevalent. Finally, we also discuss how AS can impact protein function, potentially leading to novel therapeutic targets for a range of diseases.
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Affiliation(s)
| | | | - Michael B. Clark
- Centre for Stem Cell Systems, Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, Australia
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40
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Zea DJ, Laskina S, Baudin A, Richard H, Laine E. Assessing conservation of alternative splicing with evolutionary splicing graphs. Genome Res 2021; 31:1462-1473. [PMID: 34266979 PMCID: PMC8327911 DOI: 10.1101/gr.274696.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 06/11/2021] [Indexed: 12/29/2022]
Abstract
Understanding how protein function has evolved and diversified is of great importance for human genetics and medicine. Here, we tackle the problem of describing the whole transcript variability observed in several species by generalizing the definition of splicing graph. We provide a practical solution to construct parsimonious evolutionary splicing graphs where each node is a minimal transcript building block defined across species. We show a clear link between the functional relevance, tissue regulation, and conservation of alternative transcripts on a set of 50 genes. By scaling up to the whole human protein-coding genome, we identify a few thousand genes where alternative splicing modulates the number and composition of pseudorepeats. We have implemented our approach in ThorAxe, an efficient, versatile, robust, and freely available computational tool.
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Affiliation(s)
- Diego Javier Zea
- Sorbonne Université, CNRS, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005 Paris, France
| | - Sofya Laskina
- Bioinformatics Unit (MF1), Department for Methods Development and Research Infrastructure, Robert Koch Institute, 13353 Berlin, Germany
| | - Alexis Baudin
- Sorbonne Université, CNRS, LIP6, F-75005 Paris, France
| | - Hugues Richard
- Sorbonne Université, CNRS, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005 Paris, France
- Bioinformatics Unit (MF1), Department for Methods Development and Research Infrastructure, Robert Koch Institute, 13353 Berlin, Germany
| | - Elodie Laine
- Sorbonne Université, CNRS, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005 Paris, France
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41
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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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42
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Farini D, Cesari E, Weatheritt RJ, La Sala G, Naro C, Pagliarini V, Bonvissuto D, Medici V, Guerra M, Di Pietro C, Rizzo FR, Musella A, Carola V, Centonze D, Blencowe BJ, Marazziti D, Sette C. A Dynamic Splicing Program Ensures Proper Synaptic Connections in the Developing Cerebellum. Cell Rep 2021; 31:107703. [PMID: 32492419 DOI: 10.1016/j.celrep.2020.107703] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 03/13/2020] [Accepted: 05/07/2020] [Indexed: 12/14/2022] Open
Abstract
Tight coordination of gene expression in the developing cerebellum is crucial for establishment of neuronal circuits governing motor and cognitive function. However, transcriptional changes alone do not explain all of the switches underlying neuronal differentiation. Here we unveiled a widespread and highly dynamic splicing program that affects synaptic genes in cerebellar neurons. The motifs enriched in modulated exons implicated the splicing factor Sam68 as a regulator of this program. Sam68 controls splicing of exons with weak branchpoints by directly binding near the 3' splice site and competing with U2AF recruitment. Ablation of Sam68 disrupts splicing regulation of synaptic genes associated with neurodevelopmental diseases and impairs synaptic connections and firing of Purkinje cells, resulting in motor coordination defects, ataxia, and abnormal social behavior. These findings uncover an unexpectedly dynamic splicing regulatory network that shapes the synapse in early life and establishes motor and cognitive circuitry in the developing cerebellum.
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Affiliation(s)
- Donatella Farini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy; Fondazione Santa Lucia, IRCCS, Rome, Italy
| | - Eleonora Cesari
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Robert J Weatheritt
- Donnelly Centre and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada; EMBL Australia, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Gina La Sala
- Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Rome, Italy
| | - Chiara Naro
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Davide Bonvissuto
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy
| | - Vanessa Medici
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy; Fondazione Santa Lucia, IRCCS, Rome, Italy
| | - Marika Guerra
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Chiara Di Pietro
- Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Rome, Italy
| | - Francesca Romana Rizzo
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; San Raffaele Pisana and University San Raffaele, IRCCS, Rome, Italy
| | | | - Valeria Carola
- Fondazione Santa Lucia, IRCCS, Rome, Italy; Department of Dynamic and Clinical Psychology, University of Rome Sapienza, Rome, Italy
| | - Diego Centonze
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; Unit of Neurology, IRCCS Neuromed, Pozzilli, Isernia, Italy
| | - Benjamin J Blencowe
- Donnelly Centre and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Daniela Marazziti
- Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Rome, Italy
| | - Claudio Sette
- Fondazione Santa Lucia, IRCCS, Rome, Italy; Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy.
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43
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An extended catalogue of tandem alternative splice sites in human tissue transcriptomes. PLoS Comput Biol 2021; 17:e1008329. [PMID: 33826604 PMCID: PMC8055015 DOI: 10.1371/journal.pcbi.1008329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 04/19/2021] [Accepted: 03/22/2021] [Indexed: 12/18/2022] Open
Abstract
Tandem alternative splice sites (TASS) is a special class of alternative splicing events that are characterized by a close tandem arrangement of splice sites. Most TASS lack functional characterization and are believed to arise from splicing noise. Based on the RNA-seq data from the Genotype Tissue Expression project, we present an extended catalogue of TASS in healthy human tissues and analyze their tissue-specific expression. The expression of TASS is usually dominated by one major splice site (maSS), while the expression of minor splice sites (miSS) is at least an order of magnitude lower. Among 46k miSS with sufficient read support, 9k (20%) are significantly expressed above the expected noise level, and among them 2.5k are expressed tissue-specifically. We found significant correlations between tissue-specific expression of RNA-binding proteins (RBP), tissue-specific expression of miSS, and miSS response to RBP inactivation by shRNA. In combination with RBP profiling by eCLIP, this allowed prediction of novel cases of tissue-specific splicing regulation including a miSS in QKI mRNA that is likely regulated by PTBP1. The analysis of human primary cell transcriptomes suggested that both tissue-specific and cell-type-specific factors contribute to the regulation of miSS expression. More than 20% of tissue-specific miSS affect structured protein regions and may adjust protein-protein interactions or modify the stability of the protein core. The significantly expressed miSS evolve under the same selection pressure as maSS, while other miSS lack signatures of evolutionary selection and conservation. Using mixture models, we estimated that not more than 15% of maSS and not more than 54% of tissue-specific miSS are noisy, while the proportion of noisy splice sites among non-significantly expressed miSS is above 63%. Pre-mRNA splicing is an important step in the processing of the genomic information during gene expression. During splicing, introns are excised from a gene transcript, and the remaining exons are ligated. Our work concerns one its particular subtype, which involves the so-called tandem alternative splice sites, a group of closely located exon borders that are used alternatively. We analyzed RNA-seq measurements of gene expression provided by the Genotype-Tissue Expression (GTEx) project, the largest to-date collection of such measurements in healthy human tissues, and constructed a detailed catalogue of tandem alternative splice sites. Within this catalogue, we characterized patterns of tissue-specific expression, regulation, impact on protein structure, and evolutionary selection acting on tandem alternative splice sites. In a number of genes, we predicted regulatory mechanisms that could be responsible for choosing one of many tandem alternative splice sites. The results of this study provide an invaluable resource for molecular biologists studying alternative splicing.
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44
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Chandra S, Srinivasan S, Batra J. Hepatocyte nuclear factor 1 beta: A perspective in cancer. Cancer Med 2021; 10:1791-1804. [PMID: 33580750 PMCID: PMC7940219 DOI: 10.1002/cam4.3676] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 12/17/2022] Open
Abstract
Hepatocyte nuclear factor 1 beta (HNF1 β/B) exists as a homeobox transcription factor having a vital role in the embryonic development of organs mainly liver, kidney and pancreas. Initially described as a gene causing maturity‐onset diabetes of the young (MODY), HNF1β expression deregulation and single nucleotide polymorphisms in HNF1β have now been associated with several tumours including endometrial, prostate, ovarian, hepatocellular, renal and colorectal cancers. Its function has been studied either as homodimer or heterodimer with HNF1α. In this review, the role of HNF1B in different cancers will be discussed along with the role of its splice variants, and its emerging role as a potential biomarker in cancer.
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Affiliation(s)
- Shubhra Chandra
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Australian Prostate Cancer Research Centre-Queensland, Queensland University of Technology, Brisbane, QLD, Australia.,Translational Research Institute, Woolloongabba, QLD, Australia
| | - Srilakshmi Srinivasan
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Australian Prostate Cancer Research Centre-Queensland, Queensland University of Technology, Brisbane, QLD, Australia.,Translational Research Institute, Woolloongabba, QLD, Australia
| | - Jyotsna Batra
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Australian Prostate Cancer Research Centre-Queensland, Queensland University of Technology, Brisbane, QLD, Australia.,Translational Research Institute, Woolloongabba, QLD, Australia
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45
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Salovska B, Zhu H, Gandhi T, Frank M, Li W, Rosenberger G, Wu C, Germain PL, Zhou H, Hodny Z, Reiter L, Liu Y. Isoform-resolved correlation analysis between mRNA abundance regulation and protein level degradation. Mol Syst Biol 2021; 16:e9170. [PMID: 32175694 PMCID: PMC7073818 DOI: 10.15252/msb.20199170] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 02/06/2020] [Accepted: 02/12/2020] [Indexed: 12/15/2022] Open
Abstract
Profiling of biological relationships between different molecular layers dissects regulatory mechanisms that ultimately determine cellular function. To thoroughly assess the role of protein post‐translational turnover, we devised a strategy combining pulse stable isotope‐labeled amino acids in cells (pSILAC), data‐independent acquisition mass spectrometry (DIA‐MS), and a novel data analysis framework that resolves protein degradation rate on the level of mRNA alternative splicing isoforms and isoform groups. We demonstrated our approach by the genome‐wide correlation analysis between mRNA amounts and protein degradation across different strains of HeLa cells that harbor a high grade of gene dosage variation. The dataset revealed that specific biological processes, cellular organelles, spatial compartments of organelles, and individual protein isoforms of the same genes could have distinctive degradation rate. The protein degradation diversity thus dissects the corresponding buffering or concerting protein turnover control across cancer cell lines. The data further indicate that specific mRNA splicing events such as intron retention significantly impact the protein abundance levels. Our findings support the tight association between transcriptome variability and proteostasis and provide a methodological foundation for studying functional protein degradation.
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Affiliation(s)
- Barbora Salovska
- Yale Cancer Biology Institute, Yale University, West Haven, CT, USA.,Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hongwen Zhu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | | | - Max Frank
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Wenxue Li
- Yale Cancer Biology Institute, Yale University, West Haven, CT, USA
| | | | - Chongde Wu
- Yale Cancer Biology Institute, Yale University, West Haven, CT, USA
| | - Pierre-Luc Germain
- Institute for Neuroscience, D-HEST, ETH Zurich, Zurich, Switzerland.,Statistical Bioinformatics Lab, DMLS, University of Zürich, Zurich, Switzerland
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Zdenek Hodny
- Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | | | - Yansheng Liu
- Yale Cancer Biology Institute, Yale University, West Haven, CT, USA.,Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA
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46
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Abstract
Males and females of the same species share the majority of their genomes, yet they are frequently exposed to conflicting selection pressures. Gene regulation is widely assumed to resolve these conflicting sex-specific selection pressures, and although there has been considerable focus on elucidating the role of gene expression level in sex-specific adaptation, other regulatory mechanisms have been overlooked. Alternative splicing enables different transcripts to be generated from the same gene, meaning that exons which have sex-specific beneficial effects can in theory be retained in the gene product, whereas exons with detrimental effects can be skipped. However, at present, little is known about how sex-specific selection acts on broad patterns of alternative splicing. Here, we investigate alternative splicing across males and females of multiple bird species. We identify hundreds of genes that have sex-specific patterns of splicing and establish that sex differences in splicing are correlated with phenotypic sex differences. Additionally, we find that alternatively spliced genes have evolved rapidly as a result of sex-specific selection and suggest that sex differences in splicing offer another route to sex-specific adaptation when gene expression level changes are limited by functional constraints. Overall, our results shed light on how a diverse transcriptional framework can give rise to the evolution of phenotypic sexual dimorphism.
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Affiliation(s)
- Thea F Rogers
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Daniela H Palmer
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Alison E Wright
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
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47
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Ha KCH, Sterne-Weiler T, Morris Q, Weatheritt RJ, Blencowe BJ. Differential contribution of transcriptomic regulatory layers in the definition of neuronal identity. Nat Commun 2021; 12:335. [PMID: 33436550 PMCID: PMC7804943 DOI: 10.1038/s41467-020-20483-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/25/2020] [Indexed: 12/23/2022] Open
Abstract
Previous transcriptomic profiling studies have typically focused on separately analyzing mRNA expression, alternative splicing and alternative polyadenylation differences between cell and tissue types. However, the relative contribution of these three transcriptomic regulatory layers to cell type specification is poorly understood. This question is particularly relevant to neurons, given their extensive heterogeneity associated with brain location, morphology and function. In the present study, we generated profiles for the three regulatory layers from developmentally and regionally distinct subpopulations of neurons from the mouse hippocampus and broader nervous system. Multi-omics factor analyses revealed differing contributions of each transcriptomic layer in the discrimination of neurons based on their stage of development, region, and function. Importantly, profiles of differential alternative splicing and polyadenylation better discriminated specific neuronal subtype populations than gene expression patterns. These results provide evidence for differential relative contributions of coordinated gene regulatory layers in the specification of neuronal subtypes.
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Affiliation(s)
- Kevin C H Ha
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5A 1A8, Canada
- Vector Institute, Toronto, ON, M5G 1M1, Canada
- BioSymetrics, Inc., Huntington, New York, NY, USA
| | - Timothy Sterne-Weiler
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Quaid Morris
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5A 1A8, Canada
- Vector Institute, Toronto, ON, M5G 1M1, Canada
- Department of Computer Science, University of Toronto, Toronto, ON, M5S 4G4, Canada
| | - Robert J Weatheritt
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.
- EMBL Australia, Garvan Institute of Medical Research, Darlinghurst, NSW, 2010, Australia.
- St. Vincent Clinical School, University of New South Wales, Darlinghurst, NSW, 2010, Australia.
| | - Benjamin J Blencowe
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5A 1A8, Canada.
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48
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Zhang S, Chen Y, Wang Y, Zhang P, Chen G, Zhou Y. Insights Into Translatomics in the Nervous System. Front Genet 2021; 11:599548. [PMID: 33408739 PMCID: PMC7779767 DOI: 10.3389/fgene.2020.599548] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
Most neurological disorders are caused by abnormal gene translation. Generally, dysregulation of elements involved in the translational process disrupts homeostasis in neurons and neuroglia. Better understanding of how the gene translation process occurs requires detailed analysis of transcriptomic and proteomic profile data. However, a lack of strictly direct correlations between mRNA and protein levels limits translational investigation by combining transcriptomic and proteomic profiling. The much better correlation between proteins and translated mRNAs than total mRNAs in abundance and insufficiently sensitive proteomics approach promote the requirement of advances in translatomics technology. Translatomics which capture and sequence the mRNAs associated with ribosomes has been effective in identifying translational changes by genetics or projections, ribosome stalling, local translation, and transcript isoforms in the nervous system. Here, we place emphasis on the main three translatomics methods currently used to profile mRNAs attached to ribosome-nascent chain complex (RNC-mRNA). Their prominent applications in neurological diseases including glioma, neuropathic pain, depression, fragile X syndrome (FXS), neurodegenerative disorders are outlined. The content reviewed here expands our understanding on the contributions of aberrant translation to neurological disease development.
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Affiliation(s)
- Shuxia Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yeru Chen
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yongjie Wang
- Key Laboratory of Elemene Anti-Cancer Medicine of Zhejiang Province and Holistic Integrative Pharmacy Institutes, Hangzhou Normal University, Hangzhou, China.,Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Holistic Integrative Pharmacy Institutes, Hangzhou Normal University, Hangzhou, China
| | - Piao Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Gang Chen
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Youfa Zhou
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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49
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Abstract
While the processing of mRNA is essential for gene expression, recent findings have highlighted that RNA processing is systematically altered in cancer. Mutations in RNA splicing factor genes and the shortening of 3' untranslated regions are widely observed. Moreover, evidence is accumulating that other types of RNAs, including circular RNAs, can contribute to tumorigenesis. In this Review, we highlight how altered processing or activity of coding and non-coding RNAs contributes to cancer. We introduce the regulation of gene expression by coding and non-coding RNA and discuss both established roles (microRNAs and long non-coding RNAs) and emerging roles (selective mRNA processing and circular RNAs) for RNAs, highlighting the potential mechanisms by which these RNA subtypes contribute to cancer. The widespread alteration of coding and non-coding RNA demonstrates that altered RNA biogenesis contributes to multiple hallmarks of cancer.
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Affiliation(s)
- Gregory J Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia.
- Department of Medicine, University of Adelaide, Adelaide, SA, Australia.
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia.
| | - Vihandha O Wickramasinghe
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia.
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50
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Rodriguez JM, Pozo F, di Domenico T, Vazquez J, Tress ML. An analysis of tissue-specific alternative splicing at the protein level. PLoS Comput Biol 2020; 16:e1008287. [PMID: 33017396 PMCID: PMC7561204 DOI: 10.1371/journal.pcbi.1008287] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 10/15/2020] [Accepted: 08/25/2020] [Indexed: 01/09/2023] Open
Abstract
The role of alternative splicing is one of the great unanswered questions in cellular biology. There is strong evidence for alternative splicing at the transcript level, and transcriptomics experiments show that many splice events are tissue specific. It has been suggested that alternative splicing evolved in order to remodel tissue-specific protein-protein networks. Here we investigated the evidence for tissue-specific splicing among splice isoforms detected in a large-scale proteomics analysis. Although the data supporting alternative splicing is limited at the protein level, clear patterns emerged among the small numbers of alternative splice events that we could detect in the proteomics data. More than a third of these splice events were tissue-specific and most were ancient: over 95% of splice events that were tissue-specific in both proteomics and RNAseq analyses evolved prior to the ancestors of lobe-finned fish, at least 400 million years ago. By way of contrast, three in four alternative exons in the human gene set arose in the primate lineage, so our results cannot be extrapolated to the whole genome. Tissue-specific alternative protein forms in the proteomics analysis were particularly abundant in nervous and muscle tissues and their genes had roles related to the cytoskeleton and either the structure of muscle fibres or cell-cell connections. Our results suggest that this conserved tissue-specific alternative splicing may have played a role in the development of the vertebrate brain and heart. We manually curated a set of 255 splice events detected in a large-scale tissue-based proteomics experiment and found that more than a third had evidence of significant tissue-specific differences. Events that were significantly tissue-specific at the protein level were highly conserved; almost 75% evolved over 400 million years ago. The tissues in which we found most evidence for tissue-specific splicing were nervous tissues and cardiac tissues. Genes with tissue-specific events in these two tissues had functions related to important cellular structures in brain and heart tissues. These splice events may have been essential for the development of vertebrate heart and muscle. However, our data set may not be representative of alternative exons as a whole. We found that most tissue specific splicing was strongly conserved, but just 5% of annotated alternative exons in the human gene set are ancient. More than three quarters of alternative exons are primate-derived. Although the analysis does not provide a definitive answer to the question of the functional role of alternative splicing, our results do indicate that alternative splice variants may have played a significant part in the evolution of brain and heart tissues in vertebrates.
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Affiliation(s)
- Jose Manuel Rodriguez
- Cardiovascular Proteomics Laboratory, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Calle Melchor Fernandez, Madrid, Spain
| | - Fernando Pozo
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), Calle Melchor Fernandez, Madrid, Spain
| | - Tomas di Domenico
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), Calle Melchor Fernandez, Madrid, Spain
| | - Jesus Vazquez
- Cardiovascular Proteomics Laboratory, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Calle Melchor Fernandez, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Michael L. Tress
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), Calle Melchor Fernandez, Madrid, Spain
- * E-mail:
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