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Nickerson JA, Momen-Heravi F. Long non-coding RNAs: roles in cellular stress responses and epigenetic mechanisms regulating chromatin. Nucleus 2024; 15:2350180. [PMID: 38773934 PMCID: PMC11123517 DOI: 10.1080/19491034.2024.2350180] [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: 01/18/2024] [Accepted: 04/22/2024] [Indexed: 05/24/2024] Open
Abstract
Most of the genome is transcribed into RNA but only 2% of the sequence codes for proteins. Non-coding RNA transcripts include a very large number of long noncoding RNAs (lncRNAs). A growing number of identified lncRNAs operate in cellular stress responses, for example in response to hypoxia, genotoxic stress, and oxidative stress. Additionally, lncRNA plays important roles in epigenetic mechanisms operating at chromatin and in maintaining chromatin architecture. Here, we address three lncRNA topics that have had significant recent advances. The first is an emerging role for many lncRNAs in cellular stress responses. The second is the development of high throughput screening assays to develop causal relationships between lncRNAs across the genome with cellular functions. Finally, we turn to recent advances in understanding the role of lncRNAs in regulating chromatin architecture and epigenetics, advances that build on some of the earliest work linking RNA to chromatin architecture.
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Affiliation(s)
- Jeffrey A Nickerson
- Division of Genes & Development, Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Fatemeh Momen-Heravi
- College of Dental Medicine, Columbia University Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
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2
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Shine M, Gordon J, Schärfen L, Zigackova D, Herzel L, Neugebauer KM. Co-transcriptional gene regulation in eukaryotes and prokaryotes. Nat Rev Mol Cell Biol 2024; 25:534-554. [PMID: 38509203 PMCID: PMC11199108 DOI: 10.1038/s41580-024-00706-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2024] [Indexed: 03/22/2024]
Abstract
Many steps of RNA processing occur during transcription by RNA polymerases. Co-transcriptional activities are deemed commonplace in prokaryotes, in which the lack of membrane barriers allows mixing of all gene expression steps, from transcription to translation. In the past decade, an extraordinary level of coordination between transcription and RNA processing has emerged in eukaryotes. In this Review, we discuss recent developments in our understanding of co-transcriptional gene regulation in both eukaryotes and prokaryotes, comparing methodologies and mechanisms, and highlight striking parallels in how RNA polymerases interact with the machineries that act on nascent RNA. The development of RNA sequencing and imaging techniques that detect transient transcription and RNA processing intermediates has facilitated discoveries of transcription coordination with splicing, 3'-end cleavage and dynamic RNA folding and revealed physical contacts between processing machineries and RNA polymerases. Such studies indicate that intron retention in a given nascent transcript can prevent 3'-end cleavage and cause transcriptional readthrough, which is a hallmark of eukaryotic cellular stress responses. We also discuss how coordination between nascent RNA biogenesis and transcription drives fundamental aspects of gene expression in both prokaryotes and eukaryotes.
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Affiliation(s)
- Morgan Shine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jackson Gordon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Dagmar Zigackova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Lydia Herzel
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany.
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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3
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Ietswaart R, Smalec BM, Xu A, Choquet K, McShane E, Jowhar ZM, Guegler CK, Baxter-Koenigs AR, West ER, Fu BXH, Gilbert L, Floor SN, Churchman LS. Genome-wide quantification of RNA flow across subcellular compartments reveals determinants of the mammalian transcript life cycle. Mol Cell 2024:S1097-2765(24)00511-2. [PMID: 38964322 DOI: 10.1016/j.molcel.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 05/15/2024] [Accepted: 06/11/2024] [Indexed: 07/06/2024]
Abstract
Dissecting the regulatory mechanisms controlling mammalian transcripts from production to degradation requires quantitative measurements of mRNA flow across the cell. We developed subcellular TimeLapse-seq to measure the rates at which RNAs are released from chromatin, exported from the nucleus, loaded onto polysomes, and degraded within the nucleus and cytoplasm in human and mouse cells. These rates varied substantially, yet transcripts from genes with related functions or targeted by the same transcription factors and RNA-binding proteins flowed across subcellular compartments with similar kinetics. Verifying these associations uncovered a link between DDX3X and nuclear export. For hundreds of RNA metabolism genes, most transcripts with retained introns were degraded by the nuclear exosome, while the remaining molecules were exported with stable cytoplasmic lifespans. Transcripts residing on chromatin for longer had extended poly(A) tails, whereas the reverse was observed for cytoplasmic mRNAs. Finally, machine learning identified molecular features that predicted the diverse life cycles of mRNAs.
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Affiliation(s)
- Robert Ietswaart
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
| | - Brendan M Smalec
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Albert Xu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Erik McShane
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Ziad Mohamoud Jowhar
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Chantal K Guegler
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Autum R Baxter-Koenigs
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Emma R West
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | - Luke Gilbert
- Arc Institute, Palo Alto, CA 94305, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Urology, University of California, San Francisco, San Francisco, CA 94518, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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4
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Giudice J, Jiang H. Splicing regulation through biomolecular condensates and membraneless organelles. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00739-7. [PMID: 38773325 DOI: 10.1038/s41580-024-00739-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2024] [Indexed: 05/23/2024]
Abstract
Biomolecular condensates, sometimes also known as membraneless organelles (MLOs), can form through weak multivalent intermolecular interactions of proteins and nucleic acids, a process often associated with liquid-liquid phase separation. Biomolecular condensates are emerging as sites and regulatory platforms of vital cellular functions, including transcription and RNA processing. In the first part of this Review, we comprehensively discuss how alternative splicing regulates the formation and properties of condensates, and conversely the roles of biomolecular condensates in splicing regulation. In the second part, we focus on the spatial connection between splicing regulation and nuclear MLOs such as transcriptional condensates, splicing condensates and nuclear speckles. We then discuss key studies showing how splicing regulation through biomolecular condensates is implicated in human pathologies such as neurodegenerative diseases, different types of cancer, developmental disorders and cardiomyopathies, and conclude with a discussion of outstanding questions pertaining to the roles of condensates and MLOs in splicing regulation and how to experimentally study them.
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Affiliation(s)
- Jimena Giudice
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- McAllister Heart Institute, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Hao Jiang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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5
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Yalala S, Gondane A, Poulose N, Liang J, Mills IG, Itkonen HM. CDK9 inhibition activates innate immune response through viral mimicry. FASEB J 2024; 38:e23628. [PMID: 38661032 DOI: 10.1096/fj.202302375r] [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: 11/19/2023] [Revised: 04/02/2024] [Accepted: 04/11/2024] [Indexed: 04/26/2024]
Abstract
Cancer cells frequently exhibit hyperactivation of transcription, which can lead to increased sensitivity to compounds targeting the transcriptional kinases, in particular CDK9. However, mechanistic details of CDK9 inhibition-induced cancer cell-selective anti-proliferative effects remain largely unknown. Here, we discover that CDK9 inhibition activates the innate immune response through viral mimicry in cancer cells. In MYC over-expressing prostate cancer cells, CDK9 inhibition leads to the gross accumulation of mis-spliced RNA. Double-stranded RNA (dsRNA)-activated kinase can recognize these mis-spliced RNAs, and we show that the activity of this kinase is required for the CDK9 inhibitor-induced anti-proliferative effects. Using time-resolved transcriptional profiling (SLAM-seq), targeted proteomics, and ChIP-seq, we show that, similar to viral infection, CDK9 inhibition significantly suppresses transcription of most genes but allows selective transcription and translation of cytokines related to the innate immune response. In particular, CDK9 inhibition activates NFκB-driven cytokine signaling at the transcriptional and secretome levels. The transcriptional signature induced by CDK9 inhibition identifies prostate cancers with a high level of genome instability. We propose that it is possible to induce similar effects in patients using CDK9 inhibition, which, we show, causes DNA damage in vitro. In the future, it is important to establish whether CDK9 inhibitors can potentiate the effects of immunotherapy against late-stage prostate cancer, a currently lethal disease.
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Affiliation(s)
- Shivani Yalala
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Aishwarya Gondane
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ninu Poulose
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Jing Liang
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ian G Mills
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Harri M Itkonen
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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6
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Rambout X, Maquat LE. Nuclear mRNA decay: regulatory networks that control gene expression. Nat Rev Genet 2024:10.1038/s41576-024-00712-2. [PMID: 38637632 DOI: 10.1038/s41576-024-00712-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2024] [Indexed: 04/20/2024]
Abstract
Proper regulation of mRNA production in the nucleus is critical for the maintenance of cellular homoeostasis during adaptation to internal and environmental cues. Over the past 25 years, it has become clear that the nuclear machineries governing gene transcription, pre-mRNA processing, pre-mRNA and mRNA decay, and mRNA export to the cytoplasm are inextricably linked to control the quality and quantity of mRNAs available for translation. More recently, an ever-expanding diversity of new mechanisms by which nuclear RNA decay factors finely tune the expression of protein-encoding genes have been uncovered. Here, we review the current understanding of how mammalian cells shape their protein-encoding potential by regulating the decay of pre-mRNAs and mRNAs in the nucleus.
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Affiliation(s)
- Xavier Rambout
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY, USA.
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY, USA.
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7
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González-Iglesias A, Arcas A, Domingo-Muelas A, Mancini E, Galcerán J, Valcárcel J, Fariñas I, Nieto MA. Intron detention tightly regulates the stemness/differentiation switch in the adult neurogenic niche. Nat Commun 2024; 15:2837. [PMID: 38565566 PMCID: PMC10987655 DOI: 10.1038/s41467-024-47092-z] [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: 12/06/2021] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
The adult mammalian brain retains some capacity to replenish neurons and glia, holding promise for brain regeneration. Thus, understanding the mechanisms controlling adult neural stem cell (NSC) differentiation is crucial. Paradoxically, adult NSCs in the subependymal zone transcribe genes associated with both multipotency maintenance and neural differentiation, but the mechanism that prevents conflicts in fate decisions due to these opposing transcriptional programmes is unknown. Here we describe intron detention as such control mechanism. In NSCs, while multiple mRNAs from stemness genes are spliced and exported to the cytoplasm, transcripts from differentiation genes remain unspliced and detained in the nucleus, and the opposite is true under neural differentiation conditions. We also show that m6A methylation is the mechanism that releases intron detention and triggers nuclear export, enabling rapid and synchronized responses. m6A RNA methylation operates as an on/off switch for transcripts with antagonistic functions, tightly controlling the timing of NSCs commitment to differentiation.
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Affiliation(s)
| | - Aida Arcas
- Instituto de Neurociencias (CSIC-UMH), Sant Joan d'Alacant, 03550, Spain
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research, University of Navarra, Pamplona, 31008, Spain
| | - Ana Domingo-Muelas
- Departamento de Biología Celular, Biología Funcional y Antropología Física and Instituto de Biotecnología y Biomedicina, Universidad de Valencia, Burjassot, 46100, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28029, Madrid, Spain
- Carlos Simon Foundation, 46980, Paterna, Valencia, Spain
- Department of Cell and Developmental Biology, Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Igenomix Foundation, 46980, Paterna, Valencia, Spain
| | - Estefania Mancini
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, 08003, Spain
| | - Joan Galcerán
- Instituto de Neurociencias (CSIC-UMH), Sant Joan d'Alacant, 03550, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), 28029, Madrid, Spain
| | - Juan Valcárcel
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, 08003, Spain
- Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010, Barcelona, Spain
| | - Isabel Fariñas
- Departamento de Biología Celular, Biología Funcional y Antropología Física and Instituto de Biotecnología y Biomedicina, Universidad de Valencia, Burjassot, 46100, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28029, Madrid, Spain
| | - M Angela Nieto
- Instituto de Neurociencias (CSIC-UMH), Sant Joan d'Alacant, 03550, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER), 28029, Madrid, Spain.
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8
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Nishimura K, Saika W, Inoue D. Minor introns impact on hematopoietic malignancies. Exp Hematol 2024; 132:104173. [PMID: 38309573 DOI: 10.1016/j.exphem.2024.104173] [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: 11/26/2023] [Revised: 12/25/2023] [Accepted: 01/03/2024] [Indexed: 02/05/2024]
Abstract
In the intricate orchestration of the central dogma, pre-mRNA splicing plays a crucial role in the post-transcriptional process that transforms DNA into mature mRNA. Widely acknowledged as a pivotal RNA processing step, it significantly influences gene expression and alters the functionality of gene product proteins. Although U2-dependent spliceosomes efficiently manage the removal of over 99% of introns, a distinct subset of essential genes undergo splicing with a different intron type, denoted as minor introns, using U12-dependent spliceosomes. Mutations in spliceosome component genes are now recognized as prevalent genetic abnormalities in cancer patients, especially those with hematologic malignancies. Despite the relative rarity of minor introns, genes containing them are evolutionarily conserved and play crucial roles in functions such as the RAS-MAPK pathway. Disruptions in U12-type minor intron splicing caused by mutations in snRNA or its regulatory components significantly contribute to cancer progression. Notably, recurrent mutations associated with myelodysplastic syndrome (MDS) in the minor spliceosome component ZRSR2 underscore its significance. Examination of ZRSR2-mutated MDS cells has revealed that only a subset of minor spliceosome-dependent genes, such as LZTR1, consistently exhibit missplicing. Recent technological advancements have uncovered insights into minor introns, raising inquiries beyond current understanding. This review comprehensively explores the importance of minor intron regulation, the molecular implications of minor (U12-type) spliceosomal mutations and cis-regulatory regions, and the evolutionary progress of studies on minor, aiming to provide a sophisticated understanding of their intricate role in cancer biology.
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Affiliation(s)
- Koutarou Nishimura
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Hyogo, Japan.
| | - Wataru Saika
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Hyogo, Japan; Department of Hematology, Shiga University of Medical Science, Ōtsu, Shiga, Japan
| | - Daichi Inoue
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Hyogo, Japan.
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9
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Lin CC, Chang TC, Wang Y, Guo L, Gao Y, Bikorimana E, Lemoff A, Fang YV, Zhang H, Zhang Y, Ye D, Soria-Bretones I, Servetto A, Lee KM, Luo X, Otto JJ, Akamatsu H, Napolitano F, Mani R, Cescon DW, Xu L, Xie Y, Mendell JT, Hanker AB, Arteaga CL. PRMT5 is an actionable therapeutic target in CDK4/6 inhibitor-resistant ER+/RB-deficient breast cancer. Nat Commun 2024; 15:2287. [PMID: 38480701 PMCID: PMC10937713 DOI: 10.1038/s41467-024-46495-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/29/2024] [Indexed: 03/17/2024] Open
Abstract
CDK4/6 inhibitors (CDK4/6i) have improved survival of patients with estrogen receptor-positive (ER+) breast cancer. However, patients treated with CDK4/6i eventually develop drug resistance and progress. RB1 loss-of-function alterations confer resistance to CDK4/6i, but the optimal therapy for these patients is unclear. Through a genome-wide CRISPR screen, we identify protein arginine methyltransferase 5 (PRMT5) as a molecular vulnerability in ER+/RB1-knockout breast cancer cells. Inhibition of PRMT5 blocks the G1-to-S transition in the cell cycle independent of RB, leading to growth arrest in RB1-knockout cells. Proteomics analysis uncovers fused in sarcoma (FUS) as a downstream effector of PRMT5. Inhibition of PRMT5 results in dissociation of FUS from RNA polymerase II, leading to hyperphosphorylation of serine 2 in RNA polymerase II, intron retention, and subsequent downregulation of proteins involved in DNA synthesis. Furthermore, treatment with the PRMT5 inhibitor pemrametostat and a selective ER degrader fulvestrant synergistically inhibits growth of ER+/RB-deficient cell-derived and patient-derived xenografts. These findings highlight dual ER and PRMT5 blockade as a potential therapeutic strategy to overcome resistance to CDK4/6i in ER+/RB-deficient breast cancer.
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Affiliation(s)
- Chang-Ching Lin
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Tsung-Cheng Chang
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yunguan Wang
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Lei Guo
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yunpeng Gao
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Emmanuel Bikorimana
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Andrew Lemoff
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yisheng V Fang
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - He Zhang
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yanfeng Zhang
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dan Ye
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Alberto Servetto
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Kyung-Min Lee
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Life Science, Hanyang University, Seoul, South Korea
| | - Xuemei Luo
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joseph J Otto
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Hiroaki Akamatsu
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Third Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan
| | - Fabiana Napolitano
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Ram Mani
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - David W Cescon
- Princess Margaret Cancer Centre, University of Toronto, Toronto, ON, Canada
| | - Lin Xu
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yang Xie
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joshua T Mendell
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ariella B Hanker
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Carlos L Arteaga
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA.
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10
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Chen W, Geng D, Chen J, Han X, Xie Q, Guo G, Chen X, Zhang W, Tang S, Zhong X. Roles and mechanisms of aberrant alternative splicing in melanoma - implications for targeted therapy and immunotherapy resistance. Cancer Cell Int 2024; 24:101. [PMID: 38462618 PMCID: PMC10926661 DOI: 10.1186/s12935-024-03280-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 02/22/2024] [Indexed: 03/12/2024] Open
Abstract
BACKGROUND Despite advances in therapeutic strategies, resistance to immunotherapy and the off-target effects of targeted therapy have significantly weakened the benefits for patients with melanoma. MAIN BODY Alternative splicing plays a crucial role in transcriptional reprogramming during melanoma development. In particular, aberrant alternative splicing is involved in the efficacy of immunotherapy, targeted therapy, and melanoma metastasis. Abnormal expression of splicing factors and variants may serve as biomarkers or therapeutic targets for the diagnosis and prognosis of melanoma. Therefore, comprehensively integrating their roles and related mechanisms is essential. This review provides the first detailed summary of the splicing process in melanoma and the changes occurring in this pathway. CONCLUSION The focus of this review is to provide strategies for developing novel diagnostic biomarkers and summarize their potential to alter resistance to targeted therapies and immunotherapy.
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Affiliation(s)
- Wanxian Chen
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Deyi Geng
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Jiasheng Chen
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Xiaosha Han
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Qihu Xie
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Genghong Guo
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Xuefen Chen
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Wancong Zhang
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Shijie Tang
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China
| | - Xiaoping Zhong
- Department of Plastic and Burns Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, 515000, P. R. China.
- Plastic Surgery Research Institute, Ear Deformities Treatment Center and Cleft Lip and Palate Treatment Center, Shantou University Medical College, Shantou, China.
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11
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Abdulghani M, Razavian NB, Burdick JT, Domingo E, Cheung VG, Humphrey TC. Isoform Switching Regulates the Response to Ionizing Radiation Through SRSF1. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00333-X. [PMID: 38447610 DOI: 10.1016/j.ijrobp.2024.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/23/2024] [Accepted: 02/10/2024] [Indexed: 03/08/2024]
Abstract
PURPOSE This study investigated how isoform switching affects the cellular response to ionizing radiation (IR), an understudied area despite its relevance to radiation therapy in cancer treatment. We aimed to identify changes in transcript isoform expression post-IR exposure and the proteins mediating these changes, with a focus on their potential to modulate radiosensitivity. METHODS AND MATERIALS Using RNA sequencing, we analyzed the B-cell lines derived from 10 healthy individuals at 3 timepoints, applying the mixture of isoforms algorithm to quantify alternative splicing. We examined RNA binding protein motifs within the sequences of IR-responsive isoforms and validated the serine/arginine-rich splicing factor 1 (SRSF1) as a predominant mediator through RNA immunoprecipitation. We further investigated the effects of SRSF1 on radiosensitivity by RNA interference and by analyzing publicly available data on patients with cancer. RESULTS We identified ∼1900 radiation-responsive alternatively spliced isoforms. Many isoforms were differentially expressed without changes in their overall gene expression. Over a third of these transcripts underwent exon skipping, while others used proximal last exons. These IR-responsive isoforms tended to be shorter transcripts missing vital domains for preventing apoptosis and promoting cell division but retaining those necessary for DNA repair. Our combined computational, genetic, and molecular analyses identified the proto-oncogene SRSF1 as a mediator of these radiation-induced isoform-switching events that promote apoptosis. After exposure to DNA double-strand break-inducing agents, SRSF1 expression decreased. A reduction in SRSF1 increased radiosensitivity in vitro and among patients with cancer. CONCLUSIONS We establish a pivotal role for isoform switching in the cellular response to IR and propose SRSF1 as a promising biomarker for assessing radiation therapy effectiveness.
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Affiliation(s)
- Majd Abdulghani
- Rhodes Trust and; Department of Oncology, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Niema B Razavian
- Department of Pediatrics and Life Sciences Institute, University of Michigan, Ann Arbor, Michigan
| | - Joshua T Burdick
- Department of Pediatrics and Life Sciences Institute, University of Michigan, Ann Arbor, Michigan
| | - Enric Domingo
- Department of Oncology, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Vivian G Cheung
- Department of Pediatrics and Life Sciences Institute, University of Michigan, Ann Arbor, Michigan.
| | - Timothy C Humphrey
- Department of Oncology, Medical Sciences Division, University of Oxford, Oxford, United Kingdom; Genome Damage and Stability Centre, University of Sussex, Brighton, East Sussex, United Kingdom.
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12
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Reyes AV, Shrestha R, Grismer TS, Byun D, Xu SL. Impact of alternative splicing on Arabidopsis proteome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582853. [PMID: 38496481 PMCID: PMC10942332 DOI: 10.1101/2024.02.29.582853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Alternative splicing is an important regulatory process in eukaryotes. In plants, the major form of alternative splicing is intron retention. Despite its importance, the global impact of AS on the Arabidopsis proteome has not been investigated. In this study, we address this gap by performing a comprehensive integrated analysis of how changes in AS can affect the Arabidopsis proteome using mutants that disrupt ACINUS and PININ, two evolutionarily conserved alternative splicing factors. We used tandem mass tagging (TMT) with real-time search MS3 (RTS-SPS-MS3) coupled with extensive sample fractionations to achieve very high coverage and accurate protein quantification. We then integrated our proteomic data with transcriptomic data to assess how transcript changes and increased intron retention (IIR) affect the proteome. For differentially expressed transcripts, we have observed a weak to moderate correlation between transcript changes and protein changes. Our studies revealed that some IIRs have no effect on either transcript or protein levels, while some IIRs can significantly affect protein levels. Surprisingly, we found that IIRs have a much smaller effect on increasing protein diversity. Notably, the increased intron retention events detected in the double mutant are also detected in the WT under various biotic or abiotic stresses. We further investigated the characteristics of the retained introns. Our extensive proteomic data help to guide the phenotypic analysis and reveal that collective protein changes contribute to the observed phenotypes of the increased anthocyanin, pale green, reduced growth, and short root observed in the acinus pnn double mutant. Overall, our study provides insight into the intricate regulatory mechanism of intron retention and its impact on protein abundance in plants.
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Affiliation(s)
- Andres V Reyes
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
- Carnegie Mass Spectrometry Facility, Carnegie Institution for Science, Stanford, California, USA
| | - Ruben Shrestha
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
| | - TaraBryn S Grismer
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
- Carnegie Mass Spectrometry Facility, Carnegie Institution for Science, Stanford, California, USA
| | - Danbi Byun
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
| | - Shou-Ling Xu
- Division of biosphere science and engineering, Carnegie Institution for Science, Stanford, California, USA
- Carnegie Mass Spectrometry Facility, Carnegie Institution for Science, Stanford, California, USA
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13
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Adesanya O, Das D, Kalsotra A. Emerging roles of RNA-binding proteins in fatty liver disease. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1840. [PMID: 38613185 PMCID: PMC11018357 DOI: 10.1002/wrna.1840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 02/08/2024] [Accepted: 03/05/2024] [Indexed: 04/14/2024]
Abstract
A rampant and urgent global health issue of the 21st century is the emergence and progression of fatty liver disease (FLD), including alcoholic fatty liver disease and the more heterogenous metabolism-associated (or non-alcoholic) fatty liver disease (MAFLD/NAFLD) phenotypes. These conditions manifest as disease spectra, progressing from benign hepatic steatosis to symptomatic steatohepatitis, cirrhosis, and, ultimately, hepatocellular carcinoma. With numerous intricately regulated molecular pathways implicated in its pathophysiology, recent data have emphasized the critical roles of RNA-binding proteins (RBPs) in the onset and development of FLD. They regulate gene transcription and post-transcriptional processes, including pre-mRNA splicing, capping, and polyadenylation, as well as mature mRNA transport, stability, and translation. RBP dysfunction at every point along the mRNA life cycle has been associated with altered lipid metabolism and cellular stress response, resulting in hepatic inflammation and fibrosis. Here, we discuss the current understanding of the role of RBPs in the post-transcriptional processes associated with FLD and highlight the possible and emerging therapeutic strategies leveraging RBP function for FLD treatment. This article is categorized under: RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
| | - Diptatanu Das
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Auinash Kalsotra
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Cancer Center @ Illinois, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute of Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
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14
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Ueda K, Ikeda K. Cellular carcinogenesis in preleukemic conditions:drivers and defenses. Fukushima J Med Sci 2024; 70:11-24. [PMID: 37952978 PMCID: PMC10867434 DOI: 10.5387/fms.2023-17] [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: 04/18/2023] [Accepted: 09/26/2023] [Indexed: 11/14/2023] Open
Abstract
Acute myeloid leukemia (AML) arises from preleukemic conditions. We have investigated the pathogenesis of typical preleukemia, myeloproliferative neoplasms, and clonal hematopoiesis. Hematopoietic stem cells in both preleukemic conditions harbor recurrent driver mutations; additional mutation provokes further malignant transformation, leading to AML onset. Although genetic alterations are defined as the main cause of malignant transformation, non-genetic factors are also involved in disease progression. In this review, we focus on a non-histone chromatin protein, high mobility group AT-hook2 (HMGA2), and a physiological p53 inhibitor, murine double minute X (MDMX). HMGA2 is mainly overexpressed by dysregulation of microRNAs or mutations in polycomb components, and provokes expansion of preleukemic clones through stem cell signature disruption. MDMX is overexpressed by altered splicing balance in myeloid malignancies. MDMX induces leukemic transformation from preleukemia via suppression of p53 and p53-independent activation of WNT/β-catenin signaling. We also discuss how these non-genetic factors can be targeted for leukemia prevention therapy.
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Affiliation(s)
- Koki Ueda
- Department of Blood Transfusion and Transplantation Immunology, Fukushima Medical University
| | - Kazuhiko Ikeda
- Department of Blood Transfusion and Transplantation Immunology, Fukushima Medical University
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15
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Dillingham CM, Cormaty H, Morgan EC, Tak AI, Esgdaille DE, Boutz PL, Sridharan R. KDM3A and KDM3B Maintain Naïve Pluripotency Through the Regulation of Alternative Splicing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.31.543088. [PMID: 37398291 PMCID: PMC10312572 DOI: 10.1101/2023.05.31.543088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Histone modifying enzymes play a central role in maintaining cell identity by establishing a conducive chromatin environment for lineage specific transcription factor activity. Pluripotent embryonic stem cell (ESC) identity is characterized by a lower abundance of gene repression associated histone modifications that enables rapid response to differentiation cues. The KDM3 family of histone demethylases removes the repressive histone H3 lysine 9 dimethylation (H3K9me2). Here we uncover a surprising role for the KDM3 proteins in the maintenance of the pluripotent state through post-transcriptional regulation. We find that KDM3A and KDM3B interact with RNA processing factors such as EFTUD2 and PRMT5. Acute selective degradation of the endogenous KDM3A and KDM3B proteins resulted in altered splicing independent of H3K9me2 status or catalytic activity. These splicing changes partially resemble the splicing pattern of the more blastocyst-like ground state of pluripotency and occurred in important chromatin and transcription factors such as Dnmt3b, Tbx3 and Tcf12. Our findings reveal non-canonical roles of histone demethylating enzymes in splicing to regulate cell identity.
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Affiliation(s)
- Caleb M Dillingham
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
- Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Harshini Cormaty
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Ellen C Morgan
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
| | - Andrew I Tak
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Dakarai E Esgdaille
- Department of Biochemistry and Biophysics, Center for RNA Biology, Wilmot Cancer Center, University of Rochester School of Medicine and Dentistry
| | - Paul L Boutz
- Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry
| | - Rupa Sridharan
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
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16
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Caldas P, Luz M, Baseggio S, Andrade R, Sobral D, Grosso AR. Transcription readthrough is prevalent in healthy human tissues and associated with inherent genomic features. Commun Biol 2024; 7:100. [PMID: 38225287 PMCID: PMC10789751 DOI: 10.1038/s42003-024-05779-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 01/04/2024] [Indexed: 01/17/2024] Open
Abstract
Transcription termination is a crucial step in the production of conforming mRNAs and functional proteins. Under cellular stress conditions, the transcription machinery fails to identify the termination site and continues transcribing beyond gene boundaries, a phenomenon designated as transcription readthrough. However, the prevalence and impact of this phenomenon in healthy human tissues remain unexplored. Here, we assessed transcription readthrough in almost 3000 transcriptome profiles representing 23 human tissues and found that 34% of the expressed protein-coding genes produced readthrough transcripts. The production of readthrough transcripts was restricted in genomic regions with high transcriptional activity and was associated with inefficient splicing and increased chromatin accessibility in terminal regions. In addition, we showed that these transcripts contained several binding sites for the same miRNA, unravelling a potential role as miRNA sponges. Overall, this work provides evidence that transcription readthrough is pervasive and non-stochastic, not only in abnormal conditions but also in healthy tissues. This suggests a potential role for such transcripts in modulating normal cellular functions.
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Affiliation(s)
- Paulo Caldas
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal.
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal.
| | - Mariana Luz
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Simone Baseggio
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Rita Andrade
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Daniel Sobral
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
- Genomics and Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge (INSA), Lisbon, Portugal
| | - Ana Rita Grosso
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal.
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal.
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17
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Palazzo AF, Qiu Y, Kang YM. mRNA nuclear export: how mRNA identity features distinguish functional RNAs from junk transcripts. RNA Biol 2024; 21:1-12. [PMID: 38091265 PMCID: PMC10732640 DOI: 10.1080/15476286.2023.2293339] [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] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
The division of the cellular space into nucleoplasm and cytoplasm promotes quality control mechanisms that prevent misprocessed mRNAs and junk RNAs from gaining access to the translational machinery. Here, we explore how properly processed mRNAs are distinguished from both misprocessed mRNAs and junk RNAs by the presence or absence of various 'identity features'.
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Affiliation(s)
| | - Yi Qiu
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Yoon Mo Kang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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18
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Borden KLB. The eukaryotic translation initiation factor eIF4E unexpectedly acts in splicing thereby coupling mRNA processing with translation: eIF4E induces widescale splicing reprogramming providing system-wide connectivity between splicing, nuclear mRNA export and translation. Bioessays 2024; 46:e2300145. [PMID: 37926700 PMCID: PMC11021180 DOI: 10.1002/bies.202300145] [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: 08/02/2023] [Revised: 10/17/2023] [Accepted: 10/24/2023] [Indexed: 11/07/2023]
Abstract
Recent findings position the eukaryotic translation initiation factor eIF4E as a novel modulator of mRNA splicing, a process that impacts the form and function of resultant proteins. eIF4E physically interacts with the spliceosome and with some intron-containing transcripts implying a direct role in some splicing events. Moreover, eIF4E drives the production of key components of the splicing machinery underpinning larger scale impacts on splicing. These drive eIF4E-dependent reprogramming of the splicing signature. This work completes a series of studies demonstrating eIF4E acts in all the major mRNA maturation steps whereby eIF4E drives production of the RNA processing machinery and escorts some transcripts through various maturation steps. In this way, eIF4E couples the mRNA processing-export-translation axis linking nuclear mRNA processing to cytoplasmic translation. eIF4E elevation is linked to worse outcomes in acute myeloid leukemia patients where these activities are dysregulated. Understanding these effects provides new insight into post-transcriptional control and eIF4E-driven cancers.
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Affiliation(s)
- Katherine L. B. Borden
- Institute for Research in Immunology and Cancer and Department of Pathology and Cell BiologyUniversity of MontrealMontrealQuebecCanada
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19
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Roth JF, Braunschweig U, Wu M, Li JD, Lin ZY, Larsen B, Weatheritt RJ, Gingras AC, Blencowe BJ. Systematic analysis of alternative exon-dependent interactome remodeling reveals multitasking functions of gene regulatory factors. Mol Cell 2023; 83:4222-4238.e10. [PMID: 38065061 DOI: 10.1016/j.molcel.2023.10.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 08/09/2023] [Accepted: 10/24/2023] [Indexed: 12/18/2023]
Abstract
Alternative splicing significantly expands biological complexity, particularly in the vertebrate nervous system. Increasing evidence indicates that developmental and tissue-dependent alternative exons often control protein-protein interactions; yet, only a minor fraction of these events have been characterized. Using affinity purification-mass spectrometry (AP-MS), we show that approximately 60% of analyzed neural-differential exons in proteins previously implicated in transcriptional regulation result in the gain or loss of interaction partners, which in some cases form unexpected links with coupled processes. Notably, a neural exon in Chtop regulates its interaction with the Prmt1 methyltransferase and DExD-Box helicases Ddx39b/a, affecting its methylation and activity in promoting RNA export. Additionally, a neural exon in Sap30bp affects interactions with RNA processing factors, modulating a critical function of Sap30bp in promoting the splicing of <100 nt "mini-introns" that control nuclear RNA levels. AP-MS is thus a powerful approach for elucidating the multifaceted functions of proteins imparted by context-dependent alternative exons.
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Affiliation(s)
- Jonathan F Roth
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | | | - Mingkun Wu
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jack Daiyang Li
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada
| | - Brett Larsen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada
| | - Robert J Weatheritt
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; EMBL Australia, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Benjamin J Blencowe
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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20
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Sung HM, Schott J, Boss P, Lehmann JA, Hardt MR, Lindner D, Messens J, Bogeski I, Ohler U, Stoecklin G. Stress-induced nuclear speckle reorganization is linked to activation of immediate early gene splicing. J Cell Biol 2023; 222:e202111151. [PMID: 37956386 PMCID: PMC10641589 DOI: 10.1083/jcb.202111151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 07/13/2023] [Accepted: 09/29/2023] [Indexed: 11/15/2023] Open
Abstract
Current models posit that nuclear speckles (NSs) serve as reservoirs of splicing factors and facilitate posttranscriptional mRNA processing. Here, we discovered that ribotoxic stress induces a profound reorganization of NSs with enhanced recruitment of factors required for splice-site recognition, including the RNA-binding protein TIAR, U1 snRNP proteins and U2-associated factor 65, as well as serine 2 phosphorylated RNA polymerase II. NS reorganization relies on the stress-activated p38 mitogen-activated protein kinase (MAPK) pathway and coincides with splicing activation of both pre-existing and newly synthesized pre-mRNAs. In particular, ribotoxic stress causes targeted excision of retained introns from pre-mRNAs of immediate early genes (IEGs), whose transcription is induced during the stress response. Importantly, enhanced splicing of the IEGs ZFP36 and FOS is accompanied by relocalization of the corresponding nuclear mRNA foci to NSs. Our study reveals NSs as a dynamic compartment that is remodeled under stress conditions, whereby NSs appear to become sites of IEG transcription and efficient cotranscriptional splicing.
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Affiliation(s)
- Hsu-Min Sung
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Brussels Center for Redox Biology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Johanna Schott
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Philipp Boss
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
- Department of Biology, Humboldt University, Berlin, Germany
| | - Janina A. Lehmann
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Marius Roland Hardt
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Doris Lindner
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Joris Messens
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Brussels Center for Redox Biology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Ivan Bogeski
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Uwe Ohler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
- Department of Biology, Humboldt University, Berlin, Germany
| | - Georg Stoecklin
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
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21
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Khalifah BA, Alghamdi SA, Alhasan AH. Unleashing the potential of catalytic RNAs to combat mis-spliced transcripts. Front Bioeng Biotechnol 2023; 11:1244377. [PMID: 38047291 PMCID: PMC10690607 DOI: 10.3389/fbioe.2023.1244377] [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: 06/22/2023] [Accepted: 10/23/2023] [Indexed: 12/05/2023] Open
Abstract
Human transcriptome can undergo RNA mis-splicing due to spliceopathies contributing to the increasing number of genetic diseases including muscular dystrophy (MD), Alzheimer disease (AD), Huntington disease (HD), myelodysplastic syndromes (MDS). Intron retention (IR) is a major inducer of spliceopathies where two or more introns remain in the final mature mRNA and account for many intronic expansion diseases. Potential removal of such introns for therapeutic purposes can be feasible when utilizing bioinformatics, catalytic RNAs, and nano-drug delivery systems. Overcoming delivery challenges of catalytic RNAs was discussed in this review as a future perspective highlighting the significance of utilizing synthetic biology in addition to high throughput deep sequencing and computational approaches for the treatment of mis-spliced transcripts.
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Affiliation(s)
- Bashayer A. Khalifah
- Institute for Bioengineering, Health Sector, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
- Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Ali H. Alhasan
- Institute for Bioengineering, Health Sector, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
- College of Science and General Studies, Alfaisal University, Riyadh, Saudi Arabia
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22
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Kozlowski P. Thirty Years with ERH: An mRNA Splicing and Mitosis Factor Only or Rather a Novel Genome Integrity Protector? Cells 2023; 12:2449. [PMID: 37887293 PMCID: PMC10605862 DOI: 10.3390/cells12202449] [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: 08/29/2023] [Revised: 10/10/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
ERH is a 100 to about 110 aa nuclear protein with unique primary and three-dimensional structures that are very conserved from simple eukaryotes to humans, albeit some species have lost its gene, with most higher fungi being a noteworthy example. Initially, studies on Drosophila melanogaster implied its function in pyrimidine metabolism. Subsequently, research on Xenopus laevis suggested that it acts as a transcriptional repressor. Finally, studies in humans pointed to a role in pre-mRNA splicing and in mitosis but further research, also in Caenorhabditis elegans and Schizosaccharomyces pombe, demonstrated its much broader activity, namely involvement in the biogenesis of mRNA, and miRNA, piRNA and some other ncRNAs, and in repressive heterochromatin formation. ERH interacts with numerous, mostly taxon-specific proteins, like Mmi1 and Mei2 in S. pombe, PID-3/PICS-1, TOST-1 and PID-1 in C. elegans, and DGCR8, CIZ1, PDIP46/SKAR and SAFB1/2 in humans. There are, however, some common themes in this wide range of processes and partners, such as: (a) ERH homodimerizes to form a scaffold for several complexes involved in the metabolism of nucleic acids, (b) all these RNAs are RNA polymerase II transcripts, (c) pre-mRNAs, whose splicing depends on ERH, are enriched in transcripts of DNA damage response and DNA metabolism genes, and (d) heterochromatin is formed to silence unwanted transcription, e.g., from repetitive elements. Thus, it seems that ERH has been adopted for various pathways that serve to maintain genome integrity.
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Affiliation(s)
- Piotr Kozlowski
- Department of Molecular Biology, Institute of Biochemistry, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
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23
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Hogg EKJ, Findlay GM. Functions of SRPK, CLK and DYRK kinases in stem cells, development, and human developmental disorders. FEBS Lett 2023; 597:2375-2415. [PMID: 37607329 PMCID: PMC10952393 DOI: 10.1002/1873-3468.14723] [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: 06/05/2023] [Revised: 07/08/2023] [Accepted: 07/18/2023] [Indexed: 08/24/2023]
Abstract
Human developmental disorders encompass a wide range of debilitating physical conditions and intellectual disabilities. Perturbation of protein kinase signalling underlies the development of some of these disorders. For example, disrupted SRPK signalling is associated with intellectual disabilities, and the gene dosage of DYRKs can dictate the pathology of disorders including Down's syndrome. Here, we review the emerging roles of the CMGC kinase families SRPK, CLK, DYRK, and sub-family HIPK during embryonic development and in developmental disorders. In particular, SRPK, CLK, and DYRK kinase families have key roles in developmental signalling and stem cell regulation, and can co-ordinate neuronal development and function. Genetic studies in model organisms reveal critical phenotypes including embryonic lethality, sterility, musculoskeletal errors, and most notably, altered neurological behaviours arising from defects of the neuroectoderm and altered neuronal signalling. Further unpicking the mechanisms of specific kinases using human stem cell models of neuronal differentiation and function will improve our understanding of human developmental disorders and may provide avenues for therapeutic strategies.
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Affiliation(s)
- Elizabeth K. J. Hogg
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeUK
| | - Greg M. Findlay
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeUK
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24
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Zuniga G, Frost B. Selective neuronal vulnerability to deficits in RNA processing. Prog Neurobiol 2023; 229:102500. [PMID: 37454791 DOI: 10.1016/j.pneurobio.2023.102500] [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: 05/02/2023] [Revised: 06/30/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Emerging evidence indicates that errors in RNA processing can causally drive neurodegeneration. Given that RNA produced from expressed genes of all cell types undergoes processing (splicing, polyadenylation, 5' capping, etc.), the particular vulnerability of neurons to deficits in RNA processing calls for careful consideration. The activity-dependent transcriptome remodeling associated with synaptic plasticity in neurons requires rapid, multilevel post-transcriptional RNA processing events that provide additional opportunities for dysregulation and consequent introduction or persistence of errors in RNA transcripts. Here we review the accumulating evidence that neurons have an enhanced propensity for errors in RNA processing alongside grossly insufficient defenses to clear misprocessed RNA compared to other cell types. Additionally, we explore how tau, a microtubule-associated protein implicated in Alzheimer's disease and related tauopathies, contributes to deficits in RNA processing and clearance.
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Affiliation(s)
- Gabrielle Zuniga
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Bess Frost
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA.
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25
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Zhou B, Chen N, Chen Z, Chen S, Yang J, Zheng Y, Shen L. Prmt5 deficient mouse B cells display RNA processing complexity and slower colorectal tumor progression. Eur J Immunol 2023; 53:e2250226. [PMID: 37389889 DOI: 10.1002/eji.202250226] [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: 10/20/2022] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/01/2023]
Abstract
Protein arginine methyltransferase 5 (Prmt5) is essential for normal B-cell development; however, the roles of Prmt5 in tumor-infiltrating B cells in tumor therapy have not been well elucidated. Here, we revealed that CD19-cre-Prmt5fl/fl (Prmt5cko) mice showed smaller tumor weights and volumes in the colorectal cancer mouse model; B cells expressed higher levels of Ccl22 and Il12a, which attracted T cells to the tumor site. Furthermore, we used direct RNA sequencing to comprehensively profile RNA processes in Prmt5 deletion B cells to explore underline mechanisms. We found significantly differentially expressed isoforms, mRNA splicing, poly(A) tail lengths, and m6A modification changes between the Prmt5cko and control groups. Cd74 isoform expressions might be regulated by mRNA splicing; the expression of two novel Cd74 isoforms was decreased, while one isoform was elevated in the Prmt5cko group, but the Cd74 gene expression showed no changes. We observed Ccl22, Ighg1, and Il12a expression was significantly increased in the Prmt5cko group, whereas Jak3 and Stat5b expression was decreased. Ccl22 and Ighg1 expression might be associated with poly(A) tail length, Jak3, Stat5b, and Il12a expression might be modulated by m6A modification. Our study demonstrated that Prmt5 regulates B-cell function through different mechanisms and supported the development of Prmt5-targeted antitumor treatments.
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Affiliation(s)
- Bingqian Zhou
- Department of Laboratory Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Artificial Intelligence Medicine, Shanghai Academy of Experimental Medicine, Shanghai, China
| | - Ningdai Chen
- Department of Laboratory Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Artificial Intelligence Medicine, Shanghai Academy of Experimental Medicine, Shanghai, China
| | - Zheyi Chen
- Department of Laboratory Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Artificial Intelligence Medicine, Shanghai Academy of Experimental Medicine, Shanghai, China
| | - Shiyu Chen
- Department of Laboratory Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Artificial Intelligence Medicine, Shanghai Academy of Experimental Medicine, Shanghai, China
| | - Junyao Yang
- Department of Laboratory Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Artificial Intelligence Medicine, Shanghai Academy of Experimental Medicine, Shanghai, China
| | - Yingxia Zheng
- Department of Laboratory Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Artificial Intelligence Medicine, Shanghai Academy of Experimental Medicine, Shanghai, China
| | - Lisong Shen
- Department of Laboratory Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Faculty of Medical Laboratory Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Artificial Intelligence Medicine, Shanghai Academy of Experimental Medicine, Shanghai, China
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26
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Bray C, Balcells C, McNeish IA, Keun HC. The potential and challenges of targeting MTAP-negative cancers beyond synthetic lethality. Front Oncol 2023; 13:1264785. [PMID: 37795443 PMCID: PMC10546069 DOI: 10.3389/fonc.2023.1264785] [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: 07/21/2023] [Accepted: 09/04/2023] [Indexed: 10/06/2023] Open
Abstract
Approximately 15% of cancers exhibit loss of the chromosomal locus 9p21.3 - the genomic location of the tumour suppressor gene CDKN2A and the methionine salvage gene methylthioadenosine phosphorylase (MTAP). A loss of MTAP increases the pool of its substrate methylthioadenosine (MTA), which binds to and inhibits activity of protein arginine methyltransferase 5 (PRMT5). PRMT5 utilises the universal methyl donor S-adenosylmethionine (SAM) to methylate arginine residues of protein substrates and regulate their activity, notably histones to regulate transcription. Recently, targeting PRMT5, or MAT2A that impacts PRMT5 activity by producing SAM, has shown promise as a therapeutic strategy in oncology, generating synthetic lethality in MTAP-negative cancers. However, clinical development of PRMT5 and MAT2A inhibitors has been challenging and highlights the need for further understanding of the downstream mediators of drug effects. Here, we discuss the rationale and methods for targeting the MAT2A/PRMT5 axis for cancer therapy. We evaluate the current limitations in our understanding of the mechanism of MAT2A/PRMT5 inhibitors and identify the challenges that must be addressed to maximise the potential of these drugs. In addition, we review the current literature defining downstream effectors of PRMT5 activity that could determine sensitivity to MAT2A/PRMT5 inhibition and therefore present a rationale for novel combination therapies that may not rely on synthetic lethality with MTAP loss.
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Affiliation(s)
- Chandler Bray
- Cancer Metabolism & Systems Toxicology Group, Division of Cancer, Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Cristina Balcells
- Cancer Metabolism & Systems Toxicology Group, Division of Cancer, Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Iain A. McNeish
- Ovarian Cancer Action Research Centre, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Hector C. Keun
- Cancer Metabolism & Systems Toxicology Group, Division of Cancer, Department of Surgery & Cancer, Imperial College London, London, United Kingdom
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27
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Ninomiya K, Yamazaki T, Hirose T. Satellite RNAs: emerging players in subnuclear architecture and gene regulation. EMBO J 2023; 42:e114331. [PMID: 37526230 PMCID: PMC10505914 DOI: 10.15252/embj.2023114331] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/13/2023] [Accepted: 07/22/2023] [Indexed: 08/02/2023] Open
Abstract
Satellite DNA is characterized by long, tandemly repeated sequences mainly found in centromeres and pericentromeric chromosomal regions. The recent advent of telomere-to-telomere sequencing data revealed the complete sequences of satellite regions, including centromeric α-satellites and pericentromeric HSat1-3, which together comprise ~ 5.7% of the human genome. Despite possessing constitutive heterochromatin features, these regions are transcribed to produce long noncoding RNAs with highly repetitive sequences that associate with specific sets of proteins to play various regulatory roles. In certain stress or pathological conditions, satellite RNAs are induced to assemble mesoscopic membraneless organelles. Specifically, under heat stress, nuclear stress bodies (nSBs) are scaffolded by HSat3 lncRNAs, which sequester hundreds of RNA-binding proteins. Upon removal of the stressor, nSBs recruit additional regulatory proteins, including protein kinases and RNA methylases, which modify the previously sequestered nSB components. The sequential recruitment of substrates and enzymes enables nSBs to efficiently regulate the splicing of hundreds of pre-mRNAs under limited temperature conditions. This review discusses the structural features and regulatory roles of satellite RNAs in intracellular architecture and gene regulation.
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Affiliation(s)
- Kensuke Ninomiya
- Graduate School of Frontier BiosciencesOsaka UniversitySuitaJapan
| | | | - Tetsuro Hirose
- Graduate School of Frontier BiosciencesOsaka UniversitySuitaJapan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI)Osaka UniversitySuitaJapan
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28
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Flemr M, Schwaiger M, Hess D, Iesmantavicius V, Ahel J, Tuck AC, Mohn F, Bühler M. Mouse nuclear RNAi-defective 2 promotes splicing of weak 5' splice sites. RNA (NEW YORK, N.Y.) 2023; 29:1140-1165. [PMID: 37137667 PMCID: PMC10351895 DOI: 10.1261/rna.079465.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 04/19/2023] [Indexed: 05/05/2023]
Abstract
Removal of introns during pre-mRNA splicing, which is central to gene expression, initiates by base pairing of U1 snRNA with a 5' splice site (5'SS). In mammals, many introns contain weak 5'SSs that are not efficiently recognized by the canonical U1 snRNP, suggesting alternative mechanisms exist. Here, we develop a cross-linking immunoprecipitation coupled to a high-throughput sequencing method, BCLIP-seq, to identify NRDE2 (nuclear RNAi-defective 2), and CCDC174 (coiled-coil domain-containing 174) as novel RNA-binding proteins in mouse ES cells that associate with U1 snRNA and 5'SSs. Both proteins bind directly to U1 snRNA independently of canonical U1 snRNP-specific proteins, and they are required for the selection and effective processing of weak 5'SSs. Our results reveal that mammalian cells use noncanonical splicing factors bound directly to U1 snRNA to effectively select suboptimal 5'SS sequences in hundreds of genes, promoting proper splice site choice, and accurate pre-mRNA splicing.
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Affiliation(s)
- Matyas Flemr
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Michaela Schwaiger
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, 4058 Basel, Switzerland
| | - Daniel Hess
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | | | - Josip Ahel
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Alex Charles Tuck
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Fabio Mohn
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
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29
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Choquet K, Baxter-Koenigs AR, Dülk SL, Smalec BM, Rouskin S, Churchman LS. Pre-mRNA splicing order is predetermined and maintains splicing fidelity across multi-intronic transcripts. Nat Struct Mol Biol 2023; 30:1064-1076. [PMID: 37443198 PMCID: PMC10653200 DOI: 10.1038/s41594-023-01035-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 06/13/2023] [Indexed: 07/15/2023]
Abstract
Combinatorially, intron excision within a given nascent transcript could proceed down any of thousands of paths, each of which would expose different dynamic landscapes of cis-elements and contribute to alternative splicing. In this study, we found that post-transcriptional multi-intron splicing order in human cells is largely predetermined, with most genes spliced in one or a few predominant orders. Strikingly, these orders were conserved across cell types and stages of motor neuron differentiation. Introns flanking alternatively spliced exons were frequently excised last, after their neighboring introns. Perturbations to the spliceosomal U2 snRNA altered the preferred splicing order of many genes, and these alterations were associated with the retention of other introns in the same transcript. In one gene, early removal of specific introns was sufficient to induce delayed excision of three proximal introns, and this delay was caused by two distinct cis-regulatory mechanisms. Together, our results demonstrate that multi-intron splicing order in human cells is predetermined, is influenced by a component of the spliceosome and ensures splicing fidelity across long pre-mRNAs.
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Affiliation(s)
- Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | | | - Sarah-Luisa Dülk
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Brendan M Smalec
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Silvi Rouskin
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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30
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Haque N, Will A, Cook AG, Hogg JR. A network of DZF proteins controls alternative splicing regulation and fidelity. Nucleic Acids Res 2023; 51:6411-6429. [PMID: 37144502 PMCID: PMC10325889 DOI: 10.1093/nar/gkad351] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/12/2023] [Accepted: 05/03/2023] [Indexed: 05/06/2023] Open
Abstract
Proteins containing DZF (domain associated with zinc fingers) modules play important roles throughout gene expression, from transcription to translation. Derived from nucleotidyltransferases but lacking catalytic residues, DZF domains serve as heterodimerization surfaces between DZF protein pairs. Three DZF proteins are widely expressed in mammalian tissues, ILF2, ILF3 and ZFR, which form mutually exclusive ILF2-ILF3 and ILF2-ZFR heterodimers. Using eCLIP-Seq, we find that ZFR binds across broad intronic regions to regulate the alternative splicing of cassette and mutually exclusive exons. ZFR preferentially binds dsRNA in vitro and is enriched on introns containing conserved dsRNA elements in cells. Many splicing events are similarly altered upon depletion of any of the three DZF proteins; however, we also identify independent and opposing roles for ZFR and ILF3 in alternative splicing regulation. Along with widespread involvement in cassette exon splicing, the DZF proteins control the fidelity and regulation of over a dozen highly validated mutually exclusive splicing events. Our findings indicate that the DZF proteins form a complex regulatory network that leverages dsRNA binding by ILF3 and ZFR to modulate splicing regulation and fidelity.
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Affiliation(s)
- Nazmul Haque
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD20892, USA
| | - Alexander Will
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Atlanta G Cook
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - J Robert Hogg
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD20892, USA
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31
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Rezvykh A, Ustyugov A, Chaprov K, Teterina E, Nebogatikov V, Spasskaya D, Evgen’ev M, Morozov A, Funikov S. Cytoplasmic aggregation of mutant FUS causes multistep RNA splicing perturbations in the course of motor neuron pathology. Nucleic Acids Res 2023; 51:5810-5830. [PMID: 37115004 PMCID: PMC10287951 DOI: 10.1093/nar/gkad319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Dysfunction of the RNA-binding protein (RBP) FUS implicated in RNA metabolism can cause amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. Mutations affecting FUS nuclear localization can drive RNA splicing defects and stimulate the formation of non-amyloid inclusions in affected neurons. However, the mechanism by which FUS mutations contribute to the development of ALS remains uncertain. Here we describe a pattern of RNA splicing changes in the dynamics of the continuous proteinopathy induced by mislocalized FUS. We show that the decrease in intron retention of FUS-associated transcripts represents the hallmark of the pathogenesis of ALS and is the earliest molecular event in the course of progression of the disease. As FUS aggregation increases, the pattern of RNA splicing changes, becoming more complex, including a decrease in the inclusion of neuron-specific microexons and induction of cryptic exon splicing due to the sequestration of additional RBPs into FUS aggregates. Crucially, the identified features of the pathological splicing pattern are also observed in ALS patients in both sporadic and familial cases. Our data provide evidence that both a loss of nuclear FUS function due to mislocalization and the subsequent cytoplasmic aggregation of mutant protein lead to the disruption of RNA splicing in a multistep fashion during FUS aggregation.
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Affiliation(s)
- Alexander P Rezvykh
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Aleksey A Ustyugov
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Kirill D Chaprov
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Ekaterina V Teterina
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Vladimir O Nebogatikov
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of Russian Academy of Sciences, Chernogolovka, 142432, Russian Federation
| | - Daria S Spasskaya
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Michael B Evgen’ev
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Alexey V Morozov
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Sergei Yu Funikov
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, 119991, Russian Federation
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32
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Juan-Mateu J, Valcárcel J. Minority report: The minor spliceosome as a novel cancer vulnerability factor. Mol Cell 2023; 83:1958-1960. [PMID: 37327771 DOI: 10.1016/j.molcel.2023.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 05/18/2023] [Accepted: 05/18/2023] [Indexed: 06/18/2023]
Abstract
The minor spliceosome regulates the removal of a conserved subset of introns present in genes with regulatory functions. In this issue of Molecular Cell, Augspach et al.1 report that elevated levels of U6atac snRNA, a key minor spliceosome component, contribute to prostate cancer cell growth and can be a novel therapeutic target.
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Affiliation(s)
- Jonàs Juan-Mateu
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Juan Valcárcel
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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33
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Hirano M, Galarza-Muñoz G, Nagasawa C, Schott G, Wang L, Antonia AL, Jain V, Yu X, Widen SG, Briggs FBS, Gregory SG, Ko DC, Fagg WS, Bradrick S, Garcia-Blanco MA. The RNA helicase DDX39B activates FOXP3 RNA splicing to control T regulatory cell fate. eLife 2023; 12:e76927. [PMID: 37261960 PMCID: PMC10234631 DOI: 10.7554/elife.76927] [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: 01/10/2022] [Accepted: 05/09/2023] [Indexed: 06/03/2023] Open
Abstract
Genes associated with increased susceptibility to multiple sclerosis (MS) have been identified, but their functions are incompletely understood. One of these genes codes for the RNA helicase DExD/H-Box Polypeptide 39B (DDX39B), which shows genetic and functional epistasis with interleukin-7 receptor-α gene (IL7R) in MS-risk. Based on evolutionary and functional arguments, we postulated that DDX39B enhances immune tolerance thereby decreasing MS risk. Consistent with such a role we show that DDX39B controls the expression of many MS susceptibility genes and important immune-related genes. Among these we identified Forkhead Box P3 (FOXP3), which codes for the master transcriptional factor in CD4+/CD25+ T regulatory cells. DDX39B knockdown led to loss of immune-regulatory and gain of immune-effector expression signatures. Splicing of FOXP3 introns, which belong to a previously unrecognized type of introns with C-rich polypyrimidine tracts, was exquisitely sensitive to DDX39B levels. Given the importance of FOXP3 in autoimmunity, this work cements DDX39B as an important guardian of immune tolerance.
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Affiliation(s)
- Minato Hirano
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- National Research Center for the Control and Prevention of Infectious Disease, Nagasaki UniversityNagasakiJapan
| | - Gaddiel Galarza-Muñoz
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Autoimmunity Biological SolutionsGalvestonUnited States
| | - Chloe Nagasawa
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Human Pathophysiology and Translational Medicine Program, Institute for Translational Sciences, University of Texas Medical BranchGalvestonUnited States
| | - Geraldine Schott
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
| | - Liuyang Wang
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
| | - Alejandro L Antonia
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
| | - Vaibhav Jain
- Duke Molecular Physiology Institute, Duke UniversityDurhamUnited States
| | - Xiaoying Yu
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Department of Preventive Medicine and Population Health, University of Texas Medical BranchGalvestonUnited States
| | - Steven G Widen
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
| | - Farren BS Briggs
- Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve UniversityClevelandUnited States
| | - Simon G Gregory
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
- Duke Molecular Physiology Institute, Duke UniversityDurhamUnited States
- Department of Neurology, Duke University School of MedicineDurhamUnited States
| | - Dennis C Ko
- Department of Molecular Genetics and Microbiology, Duke UniversityDurhamUnited States
- Division of Infectious Diseases, Department of Medicine, Duke UniversityDurhamUnited States
| | - William S Fagg
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Transplant Division, Department of Surgery, University of Texas Medical BranchGalvestonUnited States
| | - Shelton Bradrick
- Institute of Human Infections and Immunity, University of Texas Medical BranchGalvestonUnited States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical BranchGalvestonUnited States
- Department of Internal Medicine, University of Texas Medical BranchGalvestonUnited States
- Department of Microbiology, Immunology and Cancer Biology, University of VirginiaCharlottesvilleUnited States
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34
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Vlasenok M, Margasyuk S, Pervouchine DD. Transcriptome sequencing suggests that pre-mRNA splicing counteracts widespread intronic cleavage and polyadenylation. NAR Genom Bioinform 2023; 5:lqad051. [PMID: 37260513 PMCID: PMC10227441 DOI: 10.1093/nargab/lqad051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/09/2023] [Accepted: 05/17/2023] [Indexed: 06/02/2023] Open
Abstract
Alternative splicing (AS) and alternative polyadenylation (APA) are two crucial steps in the post-transcriptional regulation of eukaryotic gene expression. Protocols capturing and sequencing RNA 3'-ends have uncovered widespread intronic polyadenylation (IPA) in normal and disease conditions, where it is currently attributed to stochastic variations in the pre-mRNA processing. Here, we took advantage of the massive amount of RNA-seq data generated by the Genotype Tissue Expression project (GTEx) to simultaneously identify and match tissue-specific expression of intronic polyadenylation sites with tissue-specific splicing. A combination of computational methods including the analysis of short reads with non-templated adenines revealed that APA events are more abundant in introns than in exons. While the rate of IPA in composite terminal exons and skipped terminal exons expectedly correlates with splicing, we observed a considerable fraction of IPA events that lack AS support and attributed them to spliced polyadenylated introns (SPI). We hypothesize that SPIs represent transient byproducts of a dynamic coupling between APA and AS, in which the spliceosome removes the intron while it is being cleaved and polyadenylated. These findings indicate that cotranscriptional pre-mRNA splicing could serve as a rescue mechanism to suppress premature transcription termination at intronic polyadenylation sites.
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Affiliation(s)
- Maria Vlasenok
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Bulvar 30, Moscow 121205, Russia
| | - Sergey Margasyuk
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Bulvar 30, Moscow 121205, Russia
| | - Dmitri D Pervouchine
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Bulvar 30, Moscow 121205, Russia
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35
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Petrillo E. Do not panic: An intron-centric guide to alternative splicing. THE PLANT CELL 2023; 35:1752-1761. [PMID: 36648241 PMCID: PMC10226583 DOI: 10.1093/plcell/koad009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/05/2022] [Accepted: 01/11/2023] [Indexed: 05/30/2023]
Abstract
This review is an attempt to establish concepts of splicing and alternative splicing giving proper relevance to introns, the key actors in this mechanism. It might also work as a guide for those who found their favorite gene undergoes alternative splicing and could benefit from gaining a theoretical framework to understand the possible impacts of this process. This is not a thorough review of all the work in the field, but rather a critical review of some of the most relevant work done to understand the underlying mechanisms of splicing and the key questions that remain unanswered such as: What is the physiological relevance of alternative splicing? What are the functions of the different outcomes? To what extent do different alternative splicing types contribute to the proteome? Intron retention is the most frequent alternative splicing event in plants and, although scientifically neglected, it is also common in animals. This is a heterogeneous type of alternative splicing that includes different sub-types with features that have distinctive consequences in the resulting transcripts. Remarkably, intron retention can be a dead end for a transcript, but it could also be a stable intermediate whose processing is resumed upon a particular signal or change in the cell status. New sequencing technologies combined with the study of intron lariats in different conditions might help to answer key questions and could help us to understand the actual relevance of introns in gene expression regulation.
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Affiliation(s)
- Ezequiel Petrillo
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología, Molecular, y Celular, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), C1428EHA Buenos Aires, Argentina
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36
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Marquardt S, Petrillo E, Manavella PA. Cotranscriptional RNA processing and modification in plants. THE PLANT CELL 2023; 35:1654-1670. [PMID: 36259932 PMCID: PMC10226594 DOI: 10.1093/plcell/koac309] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/14/2022] [Indexed: 05/30/2023]
Abstract
The activities of RNA polymerases shape the epigenetic landscape of genomes with profound consequences for genome integrity and gene expression. A fundamental event during the regulation of eukaryotic gene expression is the coordination between transcription and RNA processing. Most primary RNAs mature through various RNA processing and modification events to become fully functional. While pioneering results positioned RNA maturation steps after transcription ends, the coupling between the maturation of diverse RNA species and their transcription is becoming increasingly evident in plants. In this review, we discuss recent advances in our understanding of the crosstalk between RNA Polymerase II, IV, and V transcription and nascent RNA processing of both coding and noncoding RNAs.
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Affiliation(s)
- Sebastian Marquardt
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Ezequiel Petrillo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Buenos Aires, C1428EHA, Argentina
| | - Pablo A Manavella
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe 3000, Argentina
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37
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Khan M, Hou S, Chen M, Lei H. Mechanisms of RNA export and nuclear retention. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1755. [PMID: 35978483 DOI: 10.1002/wrna.1755] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 06/21/2022] [Accepted: 07/06/2022] [Indexed: 05/13/2023]
Abstract
With the identification of huge amount of noncoding RNAs in recent years, the concept of RNA localization has extended from traditional mRNA export to RNA export of mRNA and ncRNA as well as nuclear retention of ncRNA. This review aims to summarize the recent findings from studies on the mechanisms of export of different RNAs and nuclear retention of some lncRNAs in higher eukaryotes, with a focus on splicing-dependent TREX recruitment for the export of spliced mRNA and the sequence-dependent mechanism of mRNA export in the absence of splicing. In addition, evidence to support the involvement of m6 A modification in RNA export with the coordination between the methylase complex and TREX complex as well as sequence-dependent nuclear retention of lncRNA is recapitulated. Finally, a model of sequence-dependent RNA localization is proposed along with the many questions that remain to be answered. This article is categorized under: RNA Export and Localization > RNA Localization RNA Export and Localization > Nuclear Export/Import.
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Affiliation(s)
- Misbah Khan
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Shuai Hou
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Mo Chen
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - Haixin Lei
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
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38
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Kwiatek L, Landry-Voyer AM, Latour M, Yague-Sanz C, Bachand F. PABPN1 prevents the nuclear export of an unspliced RNA with a constitutive transport element and controls human gene expression via intron retention. RNA (NEW YORK, N.Y.) 2023; 29:644-662. [PMID: 36754576 PMCID: PMC10158996 DOI: 10.1261/rna.079294.122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 01/12/2023] [Indexed: 05/06/2023]
Abstract
Intron retention is a type of alternative splicing where one or more introns remain unspliced in a polyadenylated transcript. Although many viral systems are known to translate proteins from mRNAs with retained introns, restriction mechanisms generally prevent export and translation of incompletely spliced mRNAs. Here, we provide evidence that the human nuclear poly(A)-binding protein, PABPN1, functions in such restrictions. Using a reporter construct in which nuclear export of an incompletely spliced mRNA is enhanced by a viral constitutive transport element (CTE), we show that PABPN1 depletion results in a significant increase in export and translation from the unspliced CTE-containing transcript. Unexpectedly, we find that inactivation of poly(A)-tail exosome targeting by depletion of PAXT components had no effect on export and translation of the unspliced reporter mRNA, suggesting a mechanism largely independent of nuclear RNA decay. Interestingly, a PABPN1 mutant selectively defective in stimulating poly(A) polymerase elongation strongly enhanced the expression of the unspliced, but not of intronless, reporter transcripts. Analysis of RNA-seq data also revealed that PABPN1 controls the expression of many human genes via intron retention. Notably, PABPN1-dependent intron retention events mostly affected 3'-terminal introns and were insensitive to PAXT and NEXT deficiencies. Our findings thus disclose a role for PABPN1 in restricting nuclear export of intron-retained transcripts and reinforce the interdependence between terminal intron splicing, 3' end processing, and polyadenylation.
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Affiliation(s)
- Lauren Kwiatek
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada J1E 4K8
| | - Anne-Marie Landry-Voyer
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada J1E 4K8
| | - Mélodie Latour
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada J1E 4K8
| | - Carlo Yague-Sanz
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada J1E 4K8
| | - Francois Bachand
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada J1E 4K8
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39
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Ueda K. Review: MDMX plays a central role in leukemic transformation and may be a promising target for leukemia prevention strategies. Exp Hematol 2023:S0301-472X(23)00161-3. [PMID: 37086813 DOI: 10.1016/j.exphem.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/24/2023]
Abstract
Acute myeloid leukemia (AML) is a fatal disease resulting from preleukemic hematopoietic conditions including asymptomatic clonal hematopoiesis. The accumulation of genetic changes is one of the causes of leukemic transformation. However, nongenetic factors including the overexpression of specific genes also contribute to preleukemic to leukemic transition. Among them, the p53 inhibitor Murine Double Minute X (MDMX) plays crucial roles especially in leukemia initiation. MDMX is broadly overexpressed in vast majority of AML cases, including in hematopoietic stem/progenitor cell (HSPC) level. Recently, high expression of MDMX in HSPC has been shown to be associated with leukemic transformation in patients with myelodysplastic syndromes, and preclinical studies demonstrated that MDMX overexpression accelerates the transformation of preleukemic murine models, including models of clonal hematopoiesis. MDMX inhibition, through activation of cell-intrinsic p53 activity, shows antileukemic effects. However, the molecular mechanisms of MDMX in provoking leukemic transformation are complicated. Both p53-dependent and independent mechanisms are involved in the progression of the disease. This review discusses the canonical and noncanonical functions of MDMX and how these functions are involved in the maintenance, expansion, and progression to malignancy of preleukemic stem cells. Moreover, strategies on how leukemic transformation could possibly be prevented by targeting MDMX in preleukemic stem cells are discussed.
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Affiliation(s)
- Koki Ueda
- Department of Blood Transfusion and Transplantation Immunology, Fukushima Medical University, Fukushima, Fukushima 9601295, Japan; Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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40
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Wong YY, Harbison JE, Hope CM, Gundsambuu B, Brown KA, Wong SW, Brown CY, Couper JJ, Breen J, Liu N, Pederson SM, Köhne M, Klee K, Schultze J, Beyer M, Sadlon T, Barry SC. Parallel recovery of chromatin accessibility and gene expression dynamics from frozen human regulatory T cells. Sci Rep 2023; 13:5506. [PMID: 37016052 PMCID: PMC10073253 DOI: 10.1038/s41598-023-32256-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 03/24/2023] [Indexed: 04/06/2023] Open
Abstract
Epigenetic features such as DNA accessibility dictate transcriptional regulation in a cell type- and cell state- specific manner, and mapping this in health vs. disease in clinically relevant material is opening the door to new mechanistic insights and new targets for therapy. Assay for Transposase Accessible Chromatin Sequencing (ATAC-seq) allows chromatin accessibility profiling from low cell input, making it tractable on rare cell populations, such as regulatory T (Treg) cells. However, little is known about the compatibility of the assay with cryopreserved rare cell populations. Here we demonstrate the robustness of an ATAC-seq protocol comparing primary Treg cells recovered from fresh or cryopreserved PBMC samples, in the steady state and in response to stimulation. We extend this method to explore the feasibility of conducting simultaneous quantitation of chromatin accessibility and transcriptome from a single aliquot of 50,000 cryopreserved Treg cells. Profiling of chromatin accessibility and gene expression in parallel within the same pool of cells controls for cellular heterogeneity and is particularly beneficial when constrained by limited input material. Overall, we observed a high correlation of accessibility patterns and transcription factor dynamics between fresh and cryopreserved samples. Furthermore, highly similar transcriptomic profiles were obtained from whole cells and from the supernatants recovered from ATAC-seq reactions. We highlight the feasibility of applying these techniques to profile the epigenomic landscape of cells recovered from cryopreservation biorepositories.
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Affiliation(s)
- Ying Y Wong
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Jessica E Harbison
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- Women's and Children's Hospital, North Adelaide, Australia
| | - Christopher M Hope
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- Women's and Children's Hospital, North Adelaide, Australia
| | | | - Katherine A Brown
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Soon W Wong
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Cheryl Y Brown
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- Women's and Children's Hospital, North Adelaide, Australia
| | - Jennifer J Couper
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- Women's and Children's Hospital, North Adelaide, Australia
| | - Jimmy Breen
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Ning Liu
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Stephen M Pederson
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Maren Köhne
- German Center for Neurodegenerative Diseases, University of Bonn, Bonn, Germany
| | - Kathrin Klee
- German Center for Neurodegenerative Diseases, University of Bonn, Bonn, Germany
| | - Joachim Schultze
- German Center for Neurodegenerative Diseases, University of Bonn, Bonn, Germany
| | - Marc Beyer
- German Center for Neurodegenerative Diseases, University of Bonn, Bonn, Germany
| | - Timothy Sadlon
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- Women's and Children's Hospital, North Adelaide, Australia
| | - Simon C Barry
- Robinson Research Institute, University of Adelaide, Adelaide, Australia.
- Women's and Children's Hospital, North Adelaide, Australia.
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41
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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: 41] [Impact Index Per Article: 41.0] [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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42
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Sun X, Liu Z, Li Z, Zeng Z, Peng W, Zhu J, Zhao J, Zhu C, Zeng C, Stearrett N, Crandall KA, Bachali P, Grammer AC, Lipsky PE. Abnormalities in intron retention characterize patients with systemic lupus erythematosus. Sci Rep 2023; 13:5141. [PMID: 36991079 PMCID: PMC10060252 DOI: 10.1038/s41598-023-31890-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 03/20/2023] [Indexed: 03/31/2023] Open
Abstract
Regulation of intron retention (IR), a form of alternative splicing, is a newly recognized checkpoint in gene expression. Since there are numerous abnormalities in gene expression in the prototypic autoimmune disease systemic lupus erythematosus (SLE), we sought to determine whether IR was intact in patients with this disease. We, therefore, studied global gene expression and IR patterns of lymphocytes in SLE patients. We analyzed RNA-seq data from peripheral blood T cell samples from 14 patients suffering from systemic lupus erythematosus (SLE) and 4 healthy controls and a second, independent data set of RNA-seq data from B cells from16 SLE patients and 4 healthy controls. We identified intron retention levels from 26,372 well annotated genes as well as differential gene expression and tested for differences between cases and controls using unbiased hierarchical clustering and principal component analysis. We followed with gene-disease enrichment analysis and gene-ontology enrichment analysis. Finally, we then tested for significant differences in intron retention between cases and controls both globally and with respect to specific genes. Overall decreased IR was found in T cells from one cohort and B cells from another cohort of patients with SLE and was associated with increased expression of numerous genes, including those encoding spliceosome components. Different introns within the same gene displayed both up- and down-regulated retention profiles indicating a complex regulatory mechanism. These results indicate that decreased IR in immune cells is characteristic of patients with active SLE and may contribute to the abnormal expression of specific genes in this autoimmune disease.
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Affiliation(s)
- Xiaoqian Sun
- Computer Science Department, George Washington University, Washington, DC, 20052, USA
| | - Zhichao Liu
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Zongzhu Li
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Zhouhao Zeng
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Weiqun Peng
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Jun Zhu
- Mokobio Biotechnology R&D Center, 1445 Research Blvd, Suite 150, Rockville, MD, 20850, USA
| | - Joel Zhao
- Walt Whitman High School, Bethesda, MD, 20817, USA
| | | | - Chen Zeng
- Physics Department, George Washington University, Washington, DC, 20052, USA.
| | - Nathaniel Stearrett
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA
| | - Keith A Crandall
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA.
| | - Prathyusha Bachali
- RILITE Research Institute and AMPEL BioSolutions, 250 W Main St, Ste 300, Charlottesville, VA, 22902, USA
| | - Amrie C Grammer
- RILITE Research Institute and AMPEL BioSolutions, 250 W Main St, Ste 300, Charlottesville, VA, 22902, USA
| | - Peter E Lipsky
- RILITE Research Institute and AMPEL BioSolutions, 250 W Main St, Ste 300, Charlottesville, VA, 22902, USA.
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43
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Rahmatpour N, Kuo LY, Kang J, Herman E, Lei L, Li M, Srinivasan S, Zipper R, Wolniak SM, Delwiche CF, Mount S, Li FW. Analyses of Marsilea vestita genome and transcriptomes do not support widespread intron retention during spermatogenesis. THE NEW PHYTOLOGIST 2023; 237:1490-1494. [PMID: 36451524 DOI: 10.1111/nph.18652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Affiliation(s)
| | - Li-Yaung Kuo
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, 300, Taiwan
| | - Jessica Kang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Eliana Herman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Lily Lei
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Muzi Li
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Sruthi Srinivasan
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Richard Zipper
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Stephen M Wolniak
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Charles F Delwiche
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Stephen Mount
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Fay-Wei Li
- Boyce Thompson Institute, Ithaca, NY, 14853, USA
- Plant Biology Section, Cornell University, Ithaca, NY, 14853, USA
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44
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Ghram M, Morris G, Culjkovic-Kraljacic B, Mars JC, Gendron P, Skrabanek L, Revuelta MV, Cerchietti L, Guzman ML, Borden KLB. The eukaryotic translation initiation factor eIF4E reprograms alternative splicing. EMBO J 2023; 42:e110496. [PMID: 36843541 PMCID: PMC10068332 DOI: 10.15252/embj.2021110496] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/28/2023] Open
Abstract
Aberrant splicing is typically attributed to splice-factor (SF) mutation and contributes to malignancies including acute myeloid leukemia (AML). Here, we discovered a mutation-independent means to extensively reprogram alternative splicing (AS). We showed that the dysregulated expression of eukaryotic translation initiation factor eIF4E elevated selective splice-factor production, thereby impacting multiple spliceosome complexes, including factors mutated in AML such as SF3B1 and U2AF1. These changes generated a splicing landscape that predominantly supported altered splice-site selection for ~800 transcripts in cell lines and ~4,600 transcripts in specimens from high-eIF4E AML patients otherwise harboring no known SF mutations. Nuclear RNA immunoprecipitations, export assays, polysome analyses, and mutational studies together revealed that eIF4E primarily increased SF production via its nuclear RNA export activity. By contrast, eIF4E dysregulation did not induce known SF mutations or alter spliceosome number. eIF4E interacted with the spliceosome and some pre-mRNAs, suggesting its direct involvement in specific splicing events. eIF4E induced simultaneous effects on numerous SF proteins, resulting in a much larger range of splicing alterations than in the case of mutation or dysregulation of individual SFs and providing a novel paradigm for splicing control and dysregulation.
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Affiliation(s)
- Mehdi Ghram
- Department of Pathology and Cell Biology, Institute for Research in Immunology and Cancer, University of Montreal, Montreal, QC, Canada.,Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC, Canada
| | - Gavin Morris
- Department of Pathology and Cell Biology, Institute for Research in Immunology and Cancer, University of Montreal, Montreal, QC, Canada.,Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC, Canada
| | - Biljana Culjkovic-Kraljacic
- Department of Pathology and Cell Biology, Institute for Research in Immunology and Cancer, University of Montreal, Montreal, QC, Canada.,Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC, Canada
| | - Jean-Clement Mars
- Department of Pathology and Cell Biology, Institute for Research in Immunology and Cancer, University of Montreal, Montreal, QC, Canada.,Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC, Canada
| | - Patrick Gendron
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC, Canada
| | - Lucy Skrabanek
- Department of Physiology and Biophysics, Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA.,Applied Bioinformatics Core, Weill Cornell Medicine, New York, NY, USA
| | - Maria Victoria Revuelta
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Leandro Cerchietti
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Monica L Guzman
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Katherine L B Borden
- Department of Pathology and Cell Biology, Institute for Research in Immunology and Cancer, University of Montreal, Montreal, QC, Canada.,Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC, Canada
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45
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Adachi H, Pan Y, He X, Chen JL, Klein B, Platenburg G, Morais P, Boutz P, Yu YT. Targeted pseudouridylation: An approach for suppressing nonsense mutations in disease genes. Mol Cell 2023; 83:637-651.e9. [PMID: 36764303 PMCID: PMC9975048 DOI: 10.1016/j.molcel.2023.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/18/2022] [Accepted: 01/05/2023] [Indexed: 02/11/2023]
Abstract
Nonsense mutations create premature termination codons (PTCs), activating the nonsense-mediated mRNA decay (NMD) pathway to degrade most PTC-containing mRNAs. The undegraded mRNA is translated, but translation terminates at the PTC, leading to no production of the full-length protein. This work presents targeted PTC pseudouridylation, an approach for nonsense suppression in human cells. Specifically, an artificial box H/ACA guide RNA designed to target the mRNA PTC can suppress both NMD and premature translation termination in various sequence contexts. Targeted pseudouridylation exhibits a level of suppression comparable with that of aminoglycoside antibiotic treatments. When targeted pseudouridylation is combined with antibiotic treatment, a much higher level of suppression is observed. Transfection of a disease model cell line (carrying a chromosomal PTC) with a designer guide RNA gene targeting the PTC also leads to nonsense suppression. Thus, targeted pseudouridylation is an RNA-directed gene-specific approach that suppresses NMD and concurrently promotes PTC readthrough.
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Affiliation(s)
- Hironori Adachi
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - Yi Pan
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - Xueyang He
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jonathan L Chen
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - Bart Klein
- ProQR Therapeutics, Leiden, the Netherlands
| | | | | | - Paul Boutz
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA; Center for Biomedical Informatics and Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA.
| | - Yi-Tao Yu
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA.
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46
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Chan SN, Pek JW. Distinct biogenesis pathways may have led to functional divergence of the human and Drosophila Arglu1 sisRNA. EMBO Rep 2023; 24:e54350. [PMID: 36533631 PMCID: PMC9900350 DOI: 10.15252/embr.202154350] [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: 11/17/2021] [Revised: 11/28/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
Stable intronic sequence RNAs (sisRNAs) are stable, long noncoding RNAs containing intronic sequences. While sisRNAs have been found across diverse species, their level of conservation remains poorly understood. Here we report that the biogenesis and functions of a sisRNA transcribed from the highly conserved Arglu1 locus are distinct in human and Drosophila melanogaster. The Arglu1 genes in both species show similar exon-intron structures where the intron 2 is orthologous and positionally conserved. In humans, Arglu1 sisRNA retains the entire intron 2 and promotes host gene splicing. Mechanistically, Arglu1 sisRNA represses the splicing-inhibitory activity of ARGLU1 protein by binding to ARGLU1 protein and promoting its localization to nuclear speckles, away from the Arglu1 gene locus. In contrast, Drosophila dArglu1 sisRNA forms via premature cleavage of intron 2 and represses host gene splicing. This repression occurs through a local accumulation of dARGLU1 protein and inhibition of telescripting by U1 snRNPs at the dArglu1 locus. We propose that distinct biogenesis of positionally conserved Arglu1 sisRNAs in both species may have led to functional divergence.
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Affiliation(s)
- Seow Neng Chan
- Temasek Life Sciences LaboratoryNational University of SingaporeSingaporeSingapore
| | - Jun Wei Pek
- Temasek Life Sciences LaboratoryNational University of SingaporeSingaporeSingapore
- Department of Biological SciencesNational University of SingaporeSingaporeSingapore
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47
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Iannone C, Kainov Y, Zhuravskaya A, Hamid F, Nojima T, Makeyev EV. PTBP1-activated co-transcriptional splicing controls epigenetic status of pluripotent stem cells. Mol Cell 2023; 83:203-218.e9. [PMID: 36626906 DOI: 10.1016/j.molcel.2022.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 11/15/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023]
Abstract
Many spliceosomal introns are excised from nascent transcripts emerging from RNA polymerase II (RNA Pol II). The extent of cell-type-specific regulation and possible functions of such co-transcriptional events remain poorly understood. We examined the role of the RNA-binding protein PTBP1 in this process using an acute depletion approach followed by the analysis of chromatin- and RNA Pol II-associated transcripts. We show that PTBP1 activates the co-transcriptional excision of hundreds of introns, a surprising effect given that this protein is known to promote intron retention. Importantly, some co-transcriptionally activated introns fail to complete their splicing without PTBP1. In a striking example, retention of a PTBP1-dependent intron triggers nonsense-mediated decay of transcripts encoding DNA methyltransferase DNMT3B. We provide evidence that this regulation facilitates the natural decline in DNMT3B levels in developing neurons and protects differentiation-specific genes from ectopic methylation. Thus, PTBP1-activated co-transcriptional splicing is a widespread phenomenon mediating epigenetic control of cellular identity.
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Affiliation(s)
- Camilla Iannone
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Yaroslav Kainov
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Anna Zhuravskaya
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Fursham Hamid
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Takayuki Nojima
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK.
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48
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de Oliveira Freitas Machado C, Schafranek M, Brüggemann M, Hernández Cañás M, Keller M, Di Liddo A, Brezski A, Blümel N, Arnold B, Bremm A, Wittig I, Jaé N, McNicoll F, Dimmeler S, Zarnack K, Müller-McNicoll M. Poison cassette exon splicing of SRSF6 regulates nuclear speckle dispersal and the response to hypoxia. Nucleic Acids Res 2023; 51:870-890. [PMID: 36620874 PMCID: PMC9881134 DOI: 10.1093/nar/gkac1225] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 12/06/2022] [Accepted: 12/10/2022] [Indexed: 01/10/2023] Open
Abstract
Hypoxia induces massive changes in alternative splicing (AS) to adapt cells to the lack of oxygen. Here, we identify the splicing factor SRSF6 as a key factor in the AS response to hypoxia. The SRSF6 level is strongly reduced in acute hypoxia, which serves a dual purpose: it allows for exon skipping and triggers the dispersal of nuclear speckles. Our data suggest that cells use dispersal of nuclear speckles to reprogram their gene expression during hypoxic adaptation and that SRSF6 plays an important role in cohesion of nuclear speckles. Down-regulation of SRSF6 is achieved through inclusion of a poison cassette exon (PCE) promoted by SRSF4. Removing the PCE 3' splice site using CRISPR/Cas9 abolishes SRSF6 reduction in hypoxia. Aberrantly high SRSF6 levels in hypoxia attenuate hypoxia-mediated AS and impair dispersal of nuclear speckles. As a consequence, proliferation and genomic instability are increased, while the stress response is suppressed. The SRSF4-PCE-SRSF6 hypoxia axis is active in different cancer types, and high SRSF6 expression in hypoxic tumors correlates with a poor prognosis. We propose that the ultra-conserved PCE of SRSF6 acts as a tumor suppressor and that its inclusion in hypoxia is crucial to reduce SRSF6 levels. This may prevent tumor cells from entering the metastatic route of hypoxia adaptation.
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Affiliation(s)
- Camila de Oliveira Freitas Machado
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany,Institute of Cardiovascular Regeneration, Goethe University, Frankfurt am Main, Germany
| | - Michal Schafranek
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
| | - Mirko Brüggemann
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany,Buchmann Institute for Molecular Life Sciences (BMLS), Frankfurt am Main, Germany
| | | | - Mario Keller
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany,Buchmann Institute for Molecular Life Sciences (BMLS), Frankfurt am Main, Germany
| | - Antonella Di Liddo
- Buchmann Institute for Molecular Life Sciences (BMLS), Frankfurt am Main, Germany
| | - Andre Brezski
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany,Buchmann Institute for Molecular Life Sciences (BMLS), Frankfurt am Main, Germany
| | - Nicole Blümel
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
| | - Benjamin Arnold
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
| | - Anja Bremm
- Institute of Biochemistry II, Goethe University, Frankfurt am Main, Germany
| | - Ilka Wittig
- Functional Proteomics, Institute of Cardiovascular Physiology, Goethe University, Frankfurt am Main, Germany
| | - Nicolas Jaé
- Institute of Cardiovascular Regeneration, Goethe University, Frankfurt am Main, Germany
| | - François McNicoll
- Institute of Molecular Biosciences, Goethe University, Frankfurt am Main, Germany
| | - Stefanie Dimmeler
- Institute of Cardiovascular Regeneration, Goethe University, Frankfurt am Main, Germany
| | - Kathi Zarnack
- Correspondence may also be addressed to Kathi Zarnack.
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49
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Zhang J, Lin X, Chen Y, Li T, Lee AC, Chow EY, Cho WC, Chan T. LAFITE Reveals the Complexity of Transcript Isoforms in Subcellular Fractions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2203480. [PMID: 36461702 PMCID: PMC9875686 DOI: 10.1002/advs.202203480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Characterization of the subcellular distribution of RNA is essential for understanding the molecular basis of biological processes. Here, the subcellular nanopore direct RNA-sequencing (DRS) of four lung cancer cell lines (A549, H1975, H358, and HCC4006) is performed, coupled with a computational pipeline, Low-abundance Aware Full-length Isoform clusTEr (LAFITE), to comprehensively analyze the full-length cytoplasmic and nuclear transcriptome. Using additional DRS and orthogonal data sets, it is shown that LAFITE outperforms current methods for detecting full-length transcripts, particularly for low-abundance isoforms that are usually overlooked due to poor read coverage. Experimental validation of six novel isoforms exclusively identified by LAFITE further confirms the reliability of this pipeline. By applying LAFITE to subcellular DRS data, the complexity of the nuclear transcriptome is revealed in terms of isoform diversity, 3'-UTR usage, m6A modification patterns, and intron retention. Overall, LAFITE provides enhanced full-length isoform identification and enables a high-resolution view of the RNA landscape at the isoform level.
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Affiliation(s)
- Jizhou Zhang
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Xiao Lin
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Yuelong Chen
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Tsz‐Ho Li
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
| | - Alan Chun‐Kit Lee
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
| | | | | | - Ting‐Fung Chan
- School of Life SciencesThe Chinese University of Hong KongShatinHong Kong SARChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SARChina
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50
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Barraza SJ, Bhattacharyya A, Trotta CR, Woll MG. Targeting strategies for modulating pre-mRNA splicing with small molecules: Recent advances. Drug Discov Today 2023; 28:103431. [PMID: 36356786 DOI: 10.1016/j.drudis.2022.103431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/27/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022]
Abstract
The concept of using small molecules to therapeutically modulate pre-mRNA splicing was validated with the US Food and Drug Administration (FDA) approval of Evrysdi® (risdiplam) in 2020. Since then, efforts have continued unabated toward the discovery of new splicing-modulating drugs. However, the drug development world has evolved in the 10 years since risdiplam precursors were first identified in high-throughput screening (HTS). Now, new mechanistic insights into RNA-processing pathways and regulatory networks afford increasingly feasible targeted approaches. In this review, organized into classes of biological target, we compile and summarize small molecules discovered, devised, and developed since 2020 to alter pre-mRNA splicing.
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Affiliation(s)
- Scott J Barraza
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, USA.
| | | | | | - Matthew G Woll
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ, USA
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