1
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Wang Y, Xie Z, Kutschera E, Adams JI, Kadash-Edmondson KE, Xing Y. rMATS-turbo: an efficient and flexible computational tool for alternative splicing analysis of large-scale RNA-seq data. Nat Protoc 2024; 19:1083-1104. [PMID: 38396040 DOI: 10.1038/s41596-023-00944-2] [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: 08/13/2022] [Accepted: 11/02/2023] [Indexed: 02/25/2024]
Abstract
Pre-mRNA alternative splicing is a prevalent mechanism for diversifying eukaryotic transcriptomes and proteomes. Regulated alternative splicing plays a role in many biological processes, and dysregulated alternative splicing is a feature of many human diseases. Short-read RNA sequencing (RNA-seq) is now the standard approach for transcriptome-wide analysis of alternative splicing. Since 2011, our laboratory has developed and maintained Replicate Multivariate Analysis of Transcript Splicing (rMATS), a computational tool for discovering and quantifying alternative splicing events from RNA-seq data. Here we provide a protocol for the contemporary version of rMATS, rMATS-turbo, a fast and scalable re-implementation that maintains the statistical framework and user interface of the original rMATS software, while incorporating a revamped computational workflow with a substantial improvement in speed and data storage efficiency. The rMATS-turbo software scales up to massive RNA-seq datasets with tens of thousands of samples. To illustrate the utility of rMATS-turbo, we describe two representative application scenarios. First, we describe a broadly applicable two-group comparison to identify differential alternative splicing events between two sample groups, including both annotated and novel alternative splicing events. Second, we describe a quantitative analysis of alternative splicing in a large-scale RNA-seq dataset (~1,000 samples), including the discovery of alternative splicing events associated with distinct cell states. We detail the workflow and features of rMATS-turbo that enable efficient parallel processing and analysis of large-scale RNA-seq datasets on a compute cluster. We anticipate that this protocol will help the broad user base of rMATS-turbo make the best use of this software for studying alternative splicing in diverse biological systems.
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Affiliation(s)
- Yuanyuan Wang
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Zhijie Xie
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Eric Kutschera
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Jenea I Adams
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Genomics and Computational Biology Graduate Program, University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn E Kadash-Edmondson
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Yi Xing
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
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2
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Shen L, Ma X, Wang Y, Wang Z, Zhang Y, Pham HQH, Tao X, Cui Y, Wei J, Lin D, Abeywanada T, Hardikar S, Halabelian L, Smith N, Chen T, Barsyte-Lovejoy D, Qiu S, Xing Y, Yang Y. Loss-of-function mutation in PRMT9 causes abnormal synapse development by dysregulation of RNA alternative splicing. Nat Commun 2024; 15:2809. [PMID: 38561334 PMCID: PMC10984984 DOI: 10.1038/s41467-024-47107-9] [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: 07/18/2023] [Accepted: 03/16/2024] [Indexed: 04/04/2024] Open
Abstract
Protein arginine methyltransferase 9 (PRMT9) is a recently identified member of the PRMT family, yet its biological function remains largely unknown. Here, by characterizing an intellectual disability associated PRMT9 mutation (G189R) and establishing a Prmt9 conditional knockout (cKO) mouse model, we uncover an important function of PRMT9 in neuronal development. The G189R mutation abolishes PRMT9 methyltransferase activity and reduces its protein stability. Knockout of Prmt9 in hippocampal neurons causes alternative splicing of ~1900 genes, which likely accounts for the aberrant synapse development and impaired learning and memory in the Prmt9 cKO mice. Mechanistically, we discover a methylation-sensitive protein-RNA interaction between the arginine 508 (R508) of the splicing factor 3B subunit 2 (SF3B2), the site that is exclusively methylated by PRMT9, and the pre-mRNA anchoring site, a cis-regulatory element that is critical for RNA splicing. Additionally, using human and mouse cell lines, as well as an SF3B2 arginine methylation-deficient mouse model, we provide strong evidence that SF3B2 is the primary methylation substrate of PRMT9, thus highlighting the conserved function of the PRMT9/SF3B2 axis in regulating pre-mRNA splicing.
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Affiliation(s)
- Lei Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Xiaokuang Ma
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Yuanyuan Wang
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, CA, 90095, USA
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Zhihao Wang
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Yi Zhang
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Hoang Quoc Hai Pham
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
- Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
| | - Xiaoqun Tao
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
- Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
| | - Yuehua Cui
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Jing Wei
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Dimitri Lin
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Tharindumala Abeywanada
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA
| | - Swanand Hardikar
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Levon Halabelian
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Noah Smith
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Taiping Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | | | - Shenfeng Qiu
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA.
| | - Yi Xing
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
| | - Yanzhong Yang
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Cancer Center, Duarte, CA, 91010, USA.
- Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA.
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3
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Shorrock HK, Lennon CD, Aliyeva A, Davey EE, DeMeo CC, Pritchard CE, Planco L, Velez JM, Mascorro-Huamancaja A, Shin DS, Cleary JD, Berglund JA. Widespread alternative splicing dysregulation occurs presymptomatically in CAG expansion spinocerebellar ataxias. Brain 2024; 147:486-504. [PMID: 37776516 PMCID: PMC10834251 DOI: 10.1093/brain/awad329] [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: 05/31/2023] [Revised: 07/31/2023] [Accepted: 09/03/2023] [Indexed: 10/02/2023] Open
Abstract
The spinocerebellar ataxias (SCAs) are a group of dominantly inherited neurodegenerative diseases, several of which are caused by CAG expansion mutations (SCAs 1, 2, 3, 6, 7 and 12) and more broadly belong to the large family of over 40 microsatellite expansion diseases. While dysregulation of alternative splicing is a well defined driver of disease pathogenesis across several microsatellite diseases, the contribution of alternative splicing in CAG expansion SCAs is poorly understood. Furthermore, despite extensive studies on differential gene expression, there remains a gap in our understanding of presymptomatic transcriptomic drivers of disease. We sought to address these knowledge gaps through a comprehensive study of 29 publicly available RNA-sequencing datasets. We identified that dysregulation of alternative splicing is widespread across CAG expansion mouse models of SCAs 1, 3 and 7. These changes were detected presymptomatically, persisted throughout disease progression, were repeat length-dependent, and were present in brain regions implicated in SCA pathogenesis including the cerebellum, pons and medulla. Across disease progression, changes in alternative splicing occurred in genes that function in pathways and processes known to be impaired in SCAs, such as ion channels, synaptic signalling, transcriptional regulation and the cytoskeleton. We validated several key alternative splicing events with known functional consequences, including Trpc3 exon 9 and Kcnma1 exon 23b, in the Atxn1154Q/2Q mouse model. Finally, we demonstrated that alternative splicing dysregulation is responsive to therapeutic intervention in CAG expansion SCAs with Atxn1 targeting antisense oligonucleotide rescuing key splicing events. Taken together, these data demonstrate that widespread presymptomatic dysregulation of alternative splicing in CAG expansion SCAs may contribute to disease onset, early neuronal dysfunction and may represent novel biomarkers across this devastating group of neurodegenerative disorders.
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Affiliation(s)
| | - Claudia D Lennon
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - Asmer Aliyeva
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
- Department of Biology, University at Albany—SUNY, Albany, NY 12222, USA
| | - Emily E Davey
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - Cristina C DeMeo
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | | | - Lori Planco
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - Jose M Velez
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
- Department of Biology, University at Albany—SUNY, Albany, NY 12222, USA
| | | | - Damian S Shin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - John D Cleary
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - J Andrew Berglund
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
- Department of Biology, University at Albany—SUNY, Albany, NY 12222, USA
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4
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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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5
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Su T, Hollas MAR, Fellers RT, Kelleher NL. Identification of Splice Variants and Isoforms in Transcriptomics and Proteomics. Annu Rev Biomed Data Sci 2023; 6:357-376. [PMID: 37561601 PMCID: PMC10840079 DOI: 10.1146/annurev-biodatasci-020722-044021] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Alternative splicing is pivotal to the regulation of gene expression and protein diversity in eukaryotic cells. The detection of alternative splicing events requires specific omics technologies. Although short-read RNA sequencing has successfully supported a plethora of investigations on alternative splicing, the emerging technologies of long-read RNA sequencing and top-down mass spectrometry open new opportunities to identify alternative splicing and protein isoforms with less ambiguity. Here, we summarize improvements in short-read RNA sequencing for alternative splicing analysis, including percent splicing index estimation and differential analysis. We also review the computational methods used in top-down proteomics analysis regarding proteoform identification, including the construction of databases of protein isoforms and statistical analyses of search results. While many improvements in sequencing and computational methods will result from emerging technologies, there should be future endeavors to increase the effectiveness, integration, and proteome coverage of alternative splicing events.
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Affiliation(s)
- Taojunfeng Su
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA;
| | - Michael A R Hollas
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
| | - Ryan T Fellers
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
| | - Neil L Kelleher
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA;
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
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6
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Muller IB, Lin M, de Jonge R, Will N, López-Navarro B, van der Laken C, Struys EA, Oudejans CBM, Assaraf YG, Cloos J, Puig-Kröger A, Jansen G. Methotrexate Provokes Disparate Folate Metabolism Gene Expression and Alternative Splicing in Ex Vivo Monocytes and GM-CSF- and M-CSF-Polarized Macrophages. Int J Mol Sci 2023; 24:9641. [PMID: 37298590 PMCID: PMC10253671 DOI: 10.3390/ijms24119641] [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: 04/14/2023] [Revised: 05/26/2023] [Accepted: 05/28/2023] [Indexed: 06/12/2023] Open
Abstract
Macrophages constitute important immune cell targets of the antifolate methotrexate (MTX) in autoimmune diseases, including rheumatoid arthritis. Regulation of folate/MTX metabolism remains poorly understood upon pro-inflammatory (M1-type/GM-CSF-polarized) and anti-inflammatory (M2-type/M-CSF-polarized) macrophages. MTX activity strictly relies on the folylpolyglutamate synthetase (FPGS) dependent intracellular conversion and hence retention to MTX-polyglutamate (MTX-PG) forms. Here, we determined FPGS pre-mRNA splicing, FPGS enzyme activity and MTX-polyglutamylation in human monocyte-derived M1- and M2-macrophages exposed to 50 nmol/L MTX ex vivo. Moreover, RNA-sequencing analysis was used to investigate global splicing profiles and differential gene expression in monocytic and MTX-exposed macrophages. Monocytes displayed six-eight-fold higher ratios of alternatively-spliced/wild type FPGS transcripts than M1- and M2-macrophages. These ratios were inversely associated with a six-ten-fold increase in FPGS activity in M1- and M2-macrophages versus monocytes. Total MTX-PG accumulation was four-fold higher in M1- versus M2-macrophages. Differential splicing after MTX-exposure was particularly apparent in M2-macrophages for histone methylation/modification genes. MTX predominantly induced differential gene expression in M1-macrophages, involving folate metabolic pathway genes, signaling pathways, chemokines/cytokines and energy metabolism. Collectively, macrophage polarization-related differences in folate/MTX metabolism and downstream pathways at the level of pre-mRNA splicing and gene expression may account for variable accumulation of MTX-PGs, hence possibly impacting MTX treatment efficacy.
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Affiliation(s)
- Ittai B. Muller
- Department of Laboratory Medicine, Amsterdam University Medical Center, 1105 AZ Amsterdam, The Netherlands; (I.B.M.); (M.L.); (R.d.J.); (E.A.S.); (C.B.M.O.)
| | - Marry Lin
- Department of Laboratory Medicine, Amsterdam University Medical Center, 1105 AZ Amsterdam, The Netherlands; (I.B.M.); (M.L.); (R.d.J.); (E.A.S.); (C.B.M.O.)
| | - Robert de Jonge
- Department of Laboratory Medicine, Amsterdam University Medical Center, 1105 AZ Amsterdam, The Netherlands; (I.B.M.); (M.L.); (R.d.J.); (E.A.S.); (C.B.M.O.)
| | - Nico Will
- Facility for Environment and Natural Science, Brandenburg Technical University Cottbus-Senftenberg, 01968 Senftenberg, Germany;
| | - Baltasar López-Navarro
- Laboratorio de Inmuno-Metabolismo e Inflamación, Instituto de Investigación Sanitaria Gregorio Marañón, Hospital Gregorio Marañón, 28007 Madrid, Spain; (B.L.-N.); (A.P.-K.)
| | - Conny van der Laken
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Center, Amsterdam University Medical Center–location VUmc, 1081 HV Amsterdam, The Netherlands;
| | - Eduard A. Struys
- Department of Laboratory Medicine, Amsterdam University Medical Center, 1105 AZ Amsterdam, The Netherlands; (I.B.M.); (M.L.); (R.d.J.); (E.A.S.); (C.B.M.O.)
| | - Cees B. M. Oudejans
- Department of Laboratory Medicine, Amsterdam University Medical Center, 1105 AZ Amsterdam, The Netherlands; (I.B.M.); (M.L.); (R.d.J.); (E.A.S.); (C.B.M.O.)
| | - Yehuda G. Assaraf
- The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel;
| | - Jacqueline Cloos
- Department of Hematology, Amsterdam University Medical Center–location VUmc, Cancer Center Amsterdam, 1081 HV Amsterdam, The Netherlands;
| | - Amaya Puig-Kröger
- Laboratorio de Inmuno-Metabolismo e Inflamación, Instituto de Investigación Sanitaria Gregorio Marañón, Hospital Gregorio Marañón, 28007 Madrid, Spain; (B.L.-N.); (A.P.-K.)
| | - Gerrit Jansen
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Center, Amsterdam University Medical Center–location VUmc, 1081 HV Amsterdam, The Netherlands;
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7
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Li L, Zhou B, Liu D, Wu H, Shi Q, Lin S, Yao W. Transcriptomic Complexity of Culm Growth and Development in Different Types of Moso Bamboo. Int J Mol Sci 2023; 24:ijms24087425. [PMID: 37108588 PMCID: PMC10138756 DOI: 10.3390/ijms24087425] [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: 02/08/2023] [Revised: 04/03/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Moso bamboo is capable of both sexual and asexual reproduction during natural growth, resulting in four distinct types of culms: the bamboo shoot-culm, the seedling stem, the leptomorph rhizome, and a long-ignored culm-the outward-rhizome. Sometimes, when the outward rhizomes break through the soil, they continue to grow longitudinally and develop into a new individual. However, the roles of alternative transcription start sites (aTSS) or termination sites (aTTS) as well as alternative splicing (AS) have not been comprehensively studied for their development. To re-annotate the moso bamboo genome and identify genome-wide aTSS, aTTS, and AS in growing culms, we utilized single-molecule long-read sequencing technology. In total, 169,433 non-redundant isoforms and 14,840 new gene loci were identified. Among 1311 lncRNAs, most of which showed a positive correlation with their target mRNAs, one-third of these IncRNAs were preferentially expressed in winter bamboo shoots. In addition, the predominant AS type observed in moso bamboo was intron retention, while aTSS and aTTS events occurred more frequently than AS. Notably, most genes with AS events were also accompanied by aTSS and aTTS events. Outward rhizome growth in moso bamboo was associated with a significant increase in intron retention, possibly due to changes in the growth environment. As different types of moso bamboo culms grow and develop, a significant number of isoforms undergo changes in their conserved domains due to the regulation of aTSS, aTTS, and AS. As a result, these isoforms may play different roles than their original functions. These isoforms then performed different functions from their original roles, contributing to the transcriptomic complexity of moso bamboo. Overall, this study provided a comprehensive overview of the transcriptomic changes underlying different types of moso bamboo culm growth and development.
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Affiliation(s)
- Long Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China
| | - Binao Zhou
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China
| | - Dong Liu
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China
| | - Hongyu Wu
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China
| | - Qianqian Shi
- College of Landscape Architecture and Art, Northwest A&F University, Xianyang 712100, China
| | - Shuyan Lin
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China
| | - Wenjing Yao
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing 210037, China
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8
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Bravo S, Leiva F, Moya J, Guzman O, Vidal R. Unveiling the Role of Dynamic Alternative Splicing Modulation After Infestation with Sea Lice (Caligus rogercresseyi) in Atlantic Salmon. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2023; 25:223-234. [PMID: 36629943 DOI: 10.1007/s10126-023-10196-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 01/04/2023] [Indexed: 05/06/2023]
Abstract
Sea lice are pathogenic marine ectoparasite copepods that represent a severe risk to the worldwide salmon industry. Several transcriptomic investigations have characterized the regulation of gene expression response of Atlantic salmon to sea lice infestation. These studies have focused on the levels of transcript, overlooking the potentially relevant role of alternative splicing (AS), which corresponds to an essential control mechanism of gene expression through RNA processing. In the present study, we performed a genome-wide bioinformatics characterization of differential AS event dynamics in control and infested C. rogercresseyi Atlantic salmon and in resistant and susceptible phenotypes. We identified a significant rise of alternative splicing events and AS genes after infestation and 176 differential alternative splicing events (DASE) from 133 genes. In addition, a higher number of DASE and AS genes were observed among resistant and susceptible phenotypes. Functional annotation of AS genes shows several terms and pathways associated with behavior, RNA splicing, immune response, and RNA binding. Furthermore, three protein-coding genes were identified undergoing differential transcript usage events, among resistant and susceptible phenotypes. Our findings support AS performing a relevant regulatory role in the response of salmonids to sea lice infestation.
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Affiliation(s)
- Scarleth Bravo
- Laboratory of Molecular Ecology, Genomics and Evolutionary Studies, Department of Biology, Universidad de Santiago de Chile, Santiago, Chile
| | - Francisco Leiva
- Laboratory of Molecular Ecology, Genomics and Evolutionary Studies, Department of Biology, Universidad de Santiago de Chile, Santiago, Chile
| | - Javier Moya
- Benchmark Animal Health Chile, Santa Rosa 560 Of.26, Puerto Varas, Chile
| | - Osiel Guzman
- IDEVAC SpA, Francisco Bilbao 1129 Of. 306, Osorno, Chile
| | - Rodrigo Vidal
- Laboratory of Molecular Ecology, Genomics and Evolutionary Studies, Department of Biology, Universidad de Santiago de Chile, Santiago, Chile.
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9
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O’Grady TM, Baddoo M, Flemington SA, Ishaq EY, Ungerleider NA, Flemington EK. Reversal of splicing infidelity is a pre-activation step in B cell differentiation. Front Immunol 2022; 13:1060114. [PMID: 36601126 PMCID: PMC9806119 DOI: 10.3389/fimmu.2022.1060114] [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: 10/02/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Introduction B cell activation and differentiation is central to the adaptive immune response. Changes in exon usage can have major impacts on cellular signaling and differentiation but have not been systematically explored in differentiating B cells. Methods We analyzed exon usage and intron retention in RNA-Seq data from subsets of human B cells at various stages of differentiation, and in an in vitro laboratory model of B cell activation and differentiation (Epstein Barr virus infection). Results Blood naïve B cells were found to have an unusual splicing profile, with unannotated splicing events in over 30% of expressed genes. Splicing changed substantially upon naïve B cell entry into secondary lymphoid tissue and before activation, involving significant increases in exon commitment and reductions in intron retention. These changes preferentially involved short introns with weak splice sites and were likely mediated by an overall increase in splicing efficiency induced by the lymphoid environment. The majority of transcripts affected by splicing changes showed restoration of encoded conserved protein domains and/or reduced targeting to the nonsense-mediated decay pathway. Affected genes were enriched in functionally important immune cell activation pathways such as antigen-mediated signaling, cell cycle control and mRNA processing and splicing. Discussion Functional observations from donor B cell subsets in progressive states of differentiation and from timecourse experiments using the in vitro model suggest that these widespread changes in mRNA splicing play a role in preparing naïve B cells for the decisive step of antigen-mediated activation and differentiation.
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Affiliation(s)
- Tina M. O’Grady
- Department of Pathology & Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, United States
| | - Melody Baddoo
- Department of Pathology & Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, United States
| | - Samuel A. Flemington
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, United States
| | - Eman Y. Ishaq
- Department of Pathology & Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, United States
| | - Nathan A. Ungerleider
- Department of Pathology & Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, United States
| | - Erik K. Flemington
- Department of Pathology & Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, United States
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Postel MD, Culver JO, Ricker C, Craig DW. Transcriptome analysis provides critical answers to the "variants of uncertain significance" conundrum. Hum Mutat 2022; 43:1590-1608. [PMID: 35510381 PMCID: PMC9560997 DOI: 10.1002/humu.24394] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/16/2022] [Accepted: 04/26/2022] [Indexed: 12/30/2022]
Abstract
While whole-genome and exome sequencing have transformed our collective understanding of genetics' role in disease pathogenesis, there are certain conditions and populations for whom DNA-level data fails to identify the underlying genetic etiology. Specifically, patients of non-White race and non-European ancestry are disproportionately affected by "variants of unknown/uncertain significance" (VUS), limiting the scope of precision medicine for minority patients and perpetuating health disparities. VUS often include deep intronic and splicing variants which are difficult to interpret from DNA data alone. RNA analysis can illuminate the consequences of VUS, thereby allowing for their reclassification as pathogenic versus benign. Here we review the critical role transcriptome analysis plays in clarifying VUS in both neoplastic and non-neoplastic diseases.
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Affiliation(s)
- Mackenzie D. Postel
- Department of Translational GenomicsUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Julie O. Culver
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Charité Ricker
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - David W. Craig
- Department of Translational GenomicsUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Keck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
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11
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Wang W, Todorov P, Pei C, Wang M, Isachenko E, Rahimi G, Mallmann P, Isachenko V. Epigenetic Alterations in Cryopreserved Human Spermatozoa: Suspected Potential Functional Defects. Cells 2022; 11:cells11132110. [PMID: 35805194 PMCID: PMC9266127 DOI: 10.3390/cells11132110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/15/2022] [Accepted: 06/24/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Gene set enrichment analysis (GSEA) was conducted on raw data, and alternative splicing (AS) events were found after mRNA sequencing of human spermatozoa. In this study, we aimed to compare unknown micro-epigenetics alternations in fresh and cryopreserved spermatozoa to evaluate the effectivity of cryopreservation protocols. Methods: Spermatozoa were divided into three groups: fresh spermatozoa (group 1), cryoprotectant-free vitrified spermatozoa (group 2), and conventionally frozen spermatozoa (group 3). Nine RNA samples (three replicates in each group) were detected and were used for library preparation with an Illumina compatible kit and sequencing by the Illumina platform. Results: Three Gene Ontology (GO) terms were found to be enriched in vitrified spermatozoa compared with fresh spermatozoa: mitochondrial tRNA aminoacylation, ATP-dependent microtubule motor activity, and male meiotic nuclear division. In alternative splicing analysis, a number of unknown AS events were found, including functional gene exon skipping (SE), alternative 5′ splice sites (A5SS), alternative 3′ splice sites (A3SS), mutually exclusive exon (MXE), and retained intron (RI). Conclusions: Cryopreservation of spermatozoa from some patients can agitate epigenetic instability, including increased alternative splicing events and changes in crucial mitochondrial functional activities. For fertilization of oocytes, for such patients, it is recommended to use fresh spermatozoa whenever possible; cryopreservation of sperm is recommended to be used only in uncontested situations.
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Affiliation(s)
- Wanxue Wang
- Department of Obstetrics and Gynaecology, Medical Faculty, Cologne University, 50931 Cologne, Germany; (W.W.); (C.P.); (M.W.); (E.I.); (G.R.); (P.M.)
| | - Plamen Todorov
- Institute of Biology and Immunology of Reproduction of Bulgarian Academy of Sciences, Tsarigradsko highway 73A, 1113 Sofia, Bulgaria;
| | - Cheng Pei
- Department of Obstetrics and Gynaecology, Medical Faculty, Cologne University, 50931 Cologne, Germany; (W.W.); (C.P.); (M.W.); (E.I.); (G.R.); (P.M.)
| | - Mengying Wang
- Department of Obstetrics and Gynaecology, Medical Faculty, Cologne University, 50931 Cologne, Germany; (W.W.); (C.P.); (M.W.); (E.I.); (G.R.); (P.M.)
| | - Evgenia Isachenko
- Department of Obstetrics and Gynaecology, Medical Faculty, Cologne University, 50931 Cologne, Germany; (W.W.); (C.P.); (M.W.); (E.I.); (G.R.); (P.M.)
| | - Gohar Rahimi
- Department of Obstetrics and Gynaecology, Medical Faculty, Cologne University, 50931 Cologne, Germany; (W.W.); (C.P.); (M.W.); (E.I.); (G.R.); (P.M.)
| | - Peter Mallmann
- Department of Obstetrics and Gynaecology, Medical Faculty, Cologne University, 50931 Cologne, Germany; (W.W.); (C.P.); (M.W.); (E.I.); (G.R.); (P.M.)
| | - Vladimir Isachenko
- Department of Obstetrics and Gynaecology, Medical Faculty, Cologne University, 50931 Cologne, Germany; (W.W.); (C.P.); (M.W.); (E.I.); (G.R.); (P.M.)
- Correspondence:
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12
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Verta JP, Jacobs A. The role of alternative splicing in adaptation and evolution. Trends Ecol Evol 2021; 37:299-308. [PMID: 34920907 DOI: 10.1016/j.tree.2021.11.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/26/2021] [Accepted: 11/19/2021] [Indexed: 01/02/2023]
Abstract
Regulation of gene expression plays a central role in adaptive divergence and evolution. Although the role of gene regulation in microevolutionary processes is gaining wide acceptance, most studies have only investigated the evolution of transcript levels, ignoring the potentially significant role of transcript structures. We argue that variation in alternative splicing plays an important and widely unexplored role in adaptation (e.g., by increasing transcriptome and/or proteome diversity, or buffering potentially deleterious genetic variation). New studies increasingly highlight the potential for independent evolution in alternative splicing and transcript level, providing alternative paths for selection to act upon. We propose that alternative splicing and transcript levels can provide contrasting, nonredundant mechanisms of equal importance for adaptive diversification of gene function and regulation.
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Affiliation(s)
- Jukka-Pekka Verta
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 9, 00790, Helsinki, Finland.
| | - Arne Jacobs
- Institute of Biodiversity, Animal Health, and Comparative Medicine, University of Glasgow, G12 8QQ, Glasgow, UK.
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13
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Karakulak T, Moch H, von Mering C, Kahraman A. Probing Isoform Switching Events in Various Cancer Types: Lessons From Pan-Cancer Studies. Front Mol Biosci 2021; 8:726902. [PMID: 34888349 PMCID: PMC8650491 DOI: 10.3389/fmolb.2021.726902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/01/2021] [Indexed: 12/03/2022] Open
Abstract
Alternative splicing is an essential regulatory mechanism for gene expression in mammalian cells contributing to protein, cellular, and species diversity. In cancer, alternative splicing is frequently disturbed, leading to changes in the expression of alternatively spliced protein isoforms. Advances in sequencing technologies and analysis methods led to new insights into the extent and functional impact of disturbed alternative splicing events. In this review, we give a brief overview of the molecular mechanisms driving alternative splicing, highlight the function of alternative splicing in healthy tissues and describe how alternative splicing is disrupted in cancer. We summarize current available computational tools for analyzing differential transcript usage, isoform switching events, and the pathogenic impact of cancer-specific splicing events. Finally, the strategies of three recent pan-cancer studies on isoform switching events are compared. Their methodological similarities and discrepancies are highlighted and lessons learned from the comparison are listed. We hope that our assessment will lead to new and more robust methods for cancer-specific transcript detection and help to produce more accurate functional impact predictions of isoform switching events.
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Affiliation(s)
- Tülay Karakulak
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
- Swiss Informatics Institute, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Holger Moch
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Christian von Mering
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Swiss Informatics Institute, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Abdullah Kahraman
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
- Swiss Informatics Institute, Swiss Institute of Bioinformatics, Lausanne, Switzerland
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