1
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Giudice J, Jiang H. Splicing regulation through biomolecular condensates and membraneless organelles. Nat Rev Mol Cell Biol 2024; 25:683-700. [PMID: 38773325 DOI: 10.1038/s41580-024-00739-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [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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2
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Dao K, Jungers CF, Djuranovic S, Mustoe AM. U-rich elements drive pervasive cryptic splicing in 3' UTR massively parallel reporter assays. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.05.606557. [PMID: 39149310 PMCID: PMC11326173 DOI: 10.1101/2024.08.05.606557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Non-coding RNA sequences play essential roles in orchestrating gene expression. However, the sequence codes and mechanisms underpinning post-transcriptional regulation remain incompletely understood. Here, we revisit the finding from a prior massively parallel reporter assay (MPRA) that AU-rich (U-rich) elements in 3' untranslated regions (3' UTRs) can drive upregulation or downregulation of mRNA expression depending on 3' UTR context. We unexpectedly discover that this variable regulation arises from widespread cryptic splicing, predominately from an unannotated splice donor in the coding sequence of GFP to diverse acceptor sites in reporter 3' UTRs. Splicing is activated by U-rich sequences, which function as potent position-dependent regulators of 5' and 3' splice site choice and overall splicing efficiency. Splicing has diverse impacts on reporter expression, causing both increases and decreases in reporter expression via multiple mechanisms. We further provide evidence that cryptic splicing impacts between 10 to 50% of measurements made by other published 3' UTR MPRAs. Overall, our work emphasizes U-rich sequences as principal drivers of splicing and provides strategies to minimize cryptic splicing artifacts in reporter assays.
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Affiliation(s)
- Khoa Dao
- Therapeutic Innovation Center (THINC), Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston TX
| | - Courtney F. Jungers
- Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis MO
| | - Sergej Djuranovic
- Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis MO
| | - Anthony M. Mustoe
- Therapeutic Innovation Center (THINC), Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston TX
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX
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3
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Paul T, Zhang P, Zhang Z, Fargason T, De Silva NIU, Powell E, Ekpenyong E, Jamal S, Yu Y, Prevelige P, Lu R, Zhang J. The U1-70K and SRSF1 interaction is modulated by phosphorylation during the early stages of spliceosome assembly. Protein Sci 2024; 33:e5117. [PMID: 39023093 PMCID: PMC11255866 DOI: 10.1002/pro.5117] [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: 03/25/2024] [Revised: 06/22/2024] [Accepted: 07/01/2024] [Indexed: 07/20/2024]
Abstract
In eukaryotes, pre-mRNA splicing is vital for RNA processing and orchestrated by the spliceosome, whose assembly starts with the interaction between U1-70K and SR proteins. Despite the significance of the U1-70K/SR interaction, the dynamic nature of the complex and the challenges in obtaining soluble U1-70K have impeded a comprehensive understanding of the interaction at the structural level for decades. We overcome the U1-70K solubility issues, enabling us to characterize the interaction between U1-70K and SRSF1, a representative SR protein. We unveil specific interactions: phosphorylated SRSF1 RS with U1-70K BAD1, and SRSF1 RRM1 with U1-70K RRM. The RS/BAD1 interaction plays a dominant role, whereas the interaction between the RRM domains further enhances the stability of the U1-70K/SRSF1 complex. The RRM interaction involves the C-terminal extension of U1-70K RRM and the conserved acid patches on SRSF1 RRM1 that is involved in SRSF1 phase separation. Our circular dichroism spectra reveal that BAD1 adapts an α-helical conformation and RS is intrinsically disordered. Intriguingly, BAD1 undergoes a conformation switch from α-helix to β-strand and random coil upon RS binding. In addition to the regulatory mechanism via SRSF1 phosphorylation, the U1-70K/SRSF1 interaction is also regulated by U1-70K BAD1 phosphorylation. We find that U1-70K phosphorylation inhibits the U1-70K and SRSF1 interaction. Our structural findings are validated through in vitro splicing assays and in-cell saturated domain scanning using the CRISPR method, providing new insights into the intricate regulatory mechanisms of pre-mRNA splicing.
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Affiliation(s)
- Trent Paul
- Department of ChemistryUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Pengcheng Zhang
- Department of Medicine, Division of Hematology/OncologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Zihan Zhang
- Department of ChemistryUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Talia Fargason
- Department of ChemistryUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | | | - Erin Powell
- Department of ChemistryUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Ethan Ekpenyong
- Department of ChemistryUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Shariq Jamal
- Department of ChemistryUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Yanbao Yu
- Department of Chemistry and BiochemistryUniversity of DelawareNewarkDelawareUSA
| | - Peter Prevelige
- Department of MicrobiologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Rui Lu
- Department of Medicine, Division of Hematology/OncologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Jun Zhang
- Department of ChemistryUniversity of Alabama at BirminghamBirminghamAlabamaUSA
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4
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Sue SH, Liu ST, Huang SM. Factors affecting the expression and stability of full-length and truncated SRSF3 proteins in human cancer cells. Sci Rep 2024; 14:14397. [PMID: 38909100 PMCID: PMC11193772 DOI: 10.1038/s41598-024-64640-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 06/11/2024] [Indexed: 06/24/2024] Open
Abstract
Alternative splicing plays a crucial role in increasing the diversity of mRNAs expressed in the genome. Serine/arginine-rich splicing factor 3 (SRSF3) is responsible for regulating the alternative splicing of its own mRNA and ensuring that its expression is balanced to maintain homeostasis. Moreover, the exon skipping of SRSF3 leads to the production of a truncated protein instead of a frameshift mutation that generates a premature termination codon (PTC). However, the precise regulatory mechanism involved in the splicing of SRSF3 remains unclear. In this study, we first established a platform for coexpressing full-length SRSF3 (SRSF3-FL) and SRSF3-PTC and further identified a specific antibody against the SRSF3-FL and truncated SRSF3 (SRSF3-TR) proteins. Next, we found that exogenously overexpressing SRSF3-FL or SRSF3-PTC failed to reverse the effects of digoxin, caffeine, or both in combination on this molecule and its targets. Endoplasmic reticulum-related pathways, transcription factors, and chemicals such as palmitic acid and phosphate were found to be involved in the regulation of SRSF3 expression. The downregulation of SRSF3-FL by palmitic acid and phosphate was mediated via different regulatory mechanisms in HeLa cells. In summary, we provide new insights into the altered expression of the SRSF3-FL and SRSF3-TR proteins for the identification of the functions of SRSF3 in cells.
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Affiliation(s)
- Sung-How Sue
- Department of Cardiovascular Surgery, Chung Shan Medical University Hospital, Chung Shan Medical University, Taichung City, 402, Taiwan, Republic of China
- Institute of Medicine, Chung Shan Medical University, Taichung City, 402, Taiwan, Republic of China
| | - Shu-Ting Liu
- Department of Biochemistry, National Defense Medical Center, Taipei City, 114, Taiwan, Republic of China
| | - Shih-Ming Huang
- Department of Biochemistry, National Defense Medical Center, Taipei City, 114, Taiwan, Republic of China.
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5
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Roesmann F, Müller L, Klaassen K, Heß S, Widera M. Interferon-Regulated Expression of Cellular Splicing Factors Modulates Multiple Levels of HIV-1 Gene Expression and Replication. Viruses 2024; 16:938. [PMID: 38932230 PMCID: PMC11209495 DOI: 10.3390/v16060938] [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: 04/30/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024] Open
Abstract
Type I interferons (IFN-Is) are pivotal in innate immunity against human immunodeficiency virus I (HIV-1) by eliciting the expression of IFN-stimulated genes (ISGs), which encompass potent host restriction factors. While ISGs restrict the viral replication within the host cell by targeting various stages of the viral life cycle, the lesser-known IFN-repressed genes (IRepGs), including RNA-binding proteins (RBPs), affect the viral replication by altering the expression of the host dependency factors that are essential for efficient HIV-1 gene expression. Both the host restriction and dependency factors determine the viral replication efficiency; however, the understanding of the IRepGs implicated in HIV-1 infection remains greatly limited at present. This review provides a comprehensive overview of the current understanding regarding the impact of the RNA-binding protein families, specifically the two families of splicing-associated proteins SRSF and hnRNP, on HIV-1 gene expression and viral replication. Since the recent findings show specifically that SRSF1 and hnRNP A0 are regulated by IFN-I in various cell lines and primary cells, including intestinal lamina propria mononuclear cells (LPMCs) and peripheral blood mononuclear cells (PBMCs), we particularly discuss their role in the context of the innate immunity affecting HIV-1 replication.
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Affiliation(s)
- Fabian Roesmann
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Lisa Müller
- Institute of Virology, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Katleen Klaassen
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Stefanie Heß
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Marek Widera
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
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6
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Paul S, Arias MA, Wen L, Liao SE, Zhang J, Wang X, Regev O, Fei J. RNA molecules display distinctive organization at nuclear speckles. iScience 2024; 27:109603. [PMID: 38638569 PMCID: PMC11024929 DOI: 10.1016/j.isci.2024.109603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/05/2024] [Accepted: 03/25/2024] [Indexed: 04/20/2024] Open
Abstract
RNA molecules often play critical roles in assisting the formation of membraneless organelles in eukaryotic cells. Yet, little is known about the organization of RNAs within membraneless organelles. Here, using super-resolution imaging and nuclear speckles as a model system, we demonstrate that different sequence domains of RNA transcripts exhibit differential spatial distributions within speckles. Specifically, we image transcripts containing a region enriched in binding motifs of serine/arginine-rich (SR) proteins and another region enriched in binding motifs of heterogeneous nuclear ribonucleoproteins (hnRNPs). We show that these transcripts localize to the outer shell of speckles, with the SR motif-rich region localizing closer to the speckle center relative to the hnRNP motif-rich region. Further, we identify that this intra-speckle RNA organization is driven by the strength of RNA-protein interactions inside and outside speckles. Our results hint at novel functional roles of nuclear speckles and likely other membraneless organelles in organizing RNA substrates for biochemical reactions.
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Affiliation(s)
- Sneha Paul
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Mauricio A. Arias
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
- Institute for System Genetics, NYU Langone Health, New York, NY 10016, USA
| | - Li Wen
- Department of Physics, The University of Chicago, Chicago, IL 60637, USA
| | - Susan E. Liao
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
| | - Jiacheng Zhang
- Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaoshu Wang
- The College, The University of Chicago, Chicago, IL 60637, USA
| | - Oded Regev
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
| | - Jingyi Fei
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
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7
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Shah K, He S, Turner DJ, Corbo J, Rebbani K, Dominguez D, Bateman JM, Cheloufi S, Igreja C, Valkov E, Murn J. Regulation by the RNA-binding protein Unkempt at its effector interface. Nat Commun 2024; 15:3159. [PMID: 38605040 PMCID: PMC11009413 DOI: 10.1038/s41467-024-47449-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 03/28/2024] [Indexed: 04/13/2024] Open
Abstract
How RNA-binding proteins (RBPs) convey regulatory instructions to the core effectors of RNA processing is unclear. Here, we document the existence and functions of a multivalent RBP-effector interface. We show that the effector interface of a conserved RBP with an essential role in metazoan development, Unkempt, is mediated by a novel type of 'dual-purpose' peptide motifs that can contact two different surfaces of interacting proteins. Unexpectedly, we find that the multivalent contacts do not merely serve effector recruitment but are required for the accuracy of RNA recognition by Unkempt. Systems analyses reveal that multivalent RBP-effector contacts can repurpose the principal activity of an effector for a different function, as we demonstrate for the reuse of the central eukaryotic mRNA decay factor CCR4-NOT in translational control. Our study establishes the molecular assembly and functional principles of an RBP-effector interface.
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Affiliation(s)
- Kriti Shah
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA, 92521, USA
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA, 92521, USA
| | - Shiyang He
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA, 92521, USA
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA, 92521, USA
| | - David J Turner
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Joshua Corbo
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - Khadija Rebbani
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Daniel Dominguez
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Joseph M Bateman
- Maurice Wohl Clinical Neuroscience Institute, King's College London, 5 Cutcombe Road, SE5 9RX, London, UK
| | - Sihem Cheloufi
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA, 92521, USA
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA, 92521, USA
- Stem Cell Center, University of California, Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Cátia Igreja
- Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, D-72076, Tübingen, Germany
| | - Eugene Valkov
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Jernej Murn
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA, 92521, USA.
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA, 92521, USA.
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8
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Zhang Z, Zhang J. Purification of SRSF1 from E. coli for Biophysical and Biochemical Assays. Curr Protoc 2024; 4:e1017. [PMID: 38578012 PMCID: PMC11168748 DOI: 10.1002/cpz1.1017] [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] [Indexed: 04/06/2024]
Abstract
The Ser/Arg-rich splicing factors (SR proteins) constitute a crucial protein family in alternative splicing, comprising twelve members characterized by unique repetitive Arg-Ser dipeptide sequences (RS) and one to two RNA-recognition motifs (RRM). The RS regions of SR proteins undergo variable phosphorylation, resulting in unphosphorylated, partially phosphorylated, or hyper-phosphorylated states based on functional requirements. Despite the identification of the SR protein family over 30 years ago, the purification of native SR proteins in soluble form at large quantities has presented challenges due to their low solubility. This protocol delineates a method for acquiring soluble, full-length, unphosphorylated, hypo- and hyper-phosphorylated SRSF1, a prototypical SR family member. Notably, this protocol facilitates the purification of SRSF1 in ample quantities suitable for NMR, as well as various biophysical and biochemical studies. The methodologies and principles outlined herein are expected to extend beyond SRSF1 protein production and can be adapted for purifying other SR protein family members or SR-related proteins, such as snRNP70 and U2AF-35. Given the involvement of these proteins in numerous essential biological processes, this protocol will prove beneficial to researchers in related fields. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Purification of SRSF1 from E. coli Support Protocol: Purification of ULP1 Basic Protocol 2: Purification of hypo-phosphorylated SRSF1 from E. coli Basic Protocol 3: Purification of hyper-phosphorylated SRSF1 from E. coli.
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Affiliation(s)
- Zihan Zhang
- Department of Chemistry, University of Alabama at Birmingham
| | - Jun Zhang
- Department of Chemistry, University of Alabama at Birmingham
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9
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Shi W, Tang J, Xiang J. Therapeutic strategies for aberrant splicing in cancer and genetic disorders. Clin Genet 2024; 105:345-354. [PMID: 38165092 DOI: 10.1111/cge.14478] [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: 09/21/2023] [Revised: 12/12/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
Accurate pre-mRNA splicing is essential for proper protein translation; however, aberrant splicing is commonly observed in the context of cancer and genetic disorders. Notably, in genetic diseases, these splicing abnormalities often play a pivotal role. Substantial challenges persist in accurately identifying and classifying disease-induced aberrant splicing, as well as in development of targeted therapeutic strategies. In this review, we examine prevalent forms of aberrant splicing and explore potential therapeutic approaches aimed at addressing these splicing-related diseases. This summary contributes to a deeper understanding of the complexities about aberrant splicing and provide a foundation for the development of effective therapeutic interventions in the field of genetic disorders and cancer.
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Affiliation(s)
- Wenhua Shi
- Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China
- Hunan Key laboratory of Early Diagnosis and Precise Treatment of Lung Cancer, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jingqun Tang
- Hunan Key laboratory of Early Diagnosis and Precise Treatment of Lung Cancer, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Thoracic Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Juanjuan Xiang
- Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China
- Hunan Key laboratory of Early Diagnosis and Precise Treatment of Lung Cancer, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- NHC Key Laboratory of Carcinogenesis and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
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10
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Tao Y, Zhang Q, Wang H, Yang X, Mu H. Alternative splicing and related RNA binding proteins in human health and disease. Signal Transduct Target Ther 2024; 9:26. [PMID: 38302461 PMCID: PMC10835012 DOI: 10.1038/s41392-024-01734-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 12/18/2023] [Accepted: 12/27/2023] [Indexed: 02/03/2024] Open
Abstract
Alternative splicing (AS) serves as a pivotal mechanism in transcriptional regulation, engendering transcript diversity, and modifications in protein structure and functionality. Across varying tissues, developmental stages, or under specific conditions, AS gives rise to distinct splice isoforms. This implies that these isoforms possess unique temporal and spatial roles, thereby associating AS with standard biological activities and diseases. Among these, AS-related RNA-binding proteins (RBPs) play an instrumental role in regulating alternative splicing events. Under physiological conditions, the diversity of proteins mediated by AS influences the structure, function, interaction, and localization of proteins, thereby participating in the differentiation and development of an array of tissues and organs. Under pathological conditions, alterations in AS are linked with various diseases, particularly cancer. These changes can lead to modifications in gene splicing patterns, culminating in changes or loss of protein functionality. For instance, in cancer, abnormalities in AS and RBPs may result in aberrant expression of cancer-associated genes, thereby promoting the onset and progression of tumors. AS and RBPs are also associated with numerous neurodegenerative diseases and autoimmune diseases. Consequently, the study of AS across different tissues holds significant value. This review provides a detailed account of the recent advancements in the study of alternative splicing and AS-related RNA-binding proteins in tissue development and diseases, which aids in deepening the understanding of gene expression complexity and offers new insights and methodologies for precision medicine.
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Affiliation(s)
- Yining Tao
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200000, Shanghai, China
- Shanghai Bone Tumor Institution, 200000, Shanghai, China
| | - Qi Zhang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, 200000, Shanghai, China
| | - Haoyu Wang
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200000, Shanghai, China
- Shanghai Bone Tumor Institution, 200000, Shanghai, China
| | - Xiyu Yang
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200000, Shanghai, China
- Shanghai Bone Tumor Institution, 200000, Shanghai, China
| | - Haoran Mu
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200000, Shanghai, China.
- Shanghai Bone Tumor Institution, 200000, Shanghai, China.
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11
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Gupta K, Yang C, McCue K, Bastani O, Sharp PA, Burge CB, Solar-Lezama A. Improved modeling of RNA-binding protein motifs in an interpretable neural model of RNA splicing. Genome Biol 2024; 25:23. [PMID: 38229106 PMCID: PMC10790492 DOI: 10.1186/s13059-023-03162-x] [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: 07/25/2023] [Accepted: 12/28/2023] [Indexed: 01/18/2024] Open
Abstract
Sequence-specific RNA-binding proteins (RBPs) play central roles in splicing decisions. Here, we describe a modular splicing architecture that leverages in vitro-derived RNA affinity models for 79 human RBPs and the annotated human genome to produce improved models of RBP binding and activity. Binding and activity are modeled by separate Motif and Aggregator components that can be mixed and matched, enforcing sparsity to improve interpretability. Training a new Adjusted Motif (AM) architecture on the splicing task not only yields better splicing predictions but also improves prediction of RBP-binding sites in vivo and of splicing activity, assessed using independent data.
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Affiliation(s)
- Kavi Gupta
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Chenxi Yang
- Department of Computer Science, University of Texas at Austin, Austin, TX, 78712, USA
| | - Kayla McCue
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Osbert Bastani
- Department of Computer and Information Science, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Phillip A Sharp
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Christopher B Burge
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Armando Solar-Lezama
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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12
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Ocharán-Mercado A, Loaeza-Loaeza J, Castro-Coronel Y, Acosta-Saavedra LC, Hernández-Kelly LC, Hernández-Sotelo D, Ortega A. RNA-Binding Proteins: A Role in Neurotoxicity? Neurotox Res 2023; 41:681-697. [PMID: 37776476 PMCID: PMC10682104 DOI: 10.1007/s12640-023-00669-w] [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: 03/15/2023] [Revised: 03/15/2023] [Accepted: 09/19/2023] [Indexed: 10/02/2023]
Abstract
Despite sustained efforts to treat neurodegenerative diseases, little is known at the molecular level to understand and generate novel therapeutic approaches for these malignancies. Therefore, it is not surprising that neurogenerative diseases are among the leading causes of death in the aged population. Neurons require sophisticated cellular mechanisms to maintain proper protein homeostasis. These cells are generally sensitive to loss of gene expression control at the post-transcriptional level. Post-translational control responds to signals that can arise from intracellular processes or environmental factors that can be regulated through RNA-binding proteins. These proteins recognize RNA through one or more RNA-binding domains and form ribonucleoproteins that are critically involved in the regulation of post-transcriptional processes from splicing to the regulation of association of the translation machinery allowing a relatively rapid and precise modulation of the transcriptome. Neurotoxicity is the result of the biological, chemical, or physical interaction of agents with an adverse effect on the structure and function of the central nervous system. The disruption of the proper levels or function of RBPs in neurons and glial cells triggers neurotoxic events that are linked to neurodegenerative diseases such as spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), fragile X syndrome (FXS), and frontotemporal dementia (FTD) among many others. The connection between RBPs and neurodegenerative diseases opens a new landscape for potentially novel therapeutic targets for the intervention of these neurodegenerative pathologies. In this contribution, a summary of the recent findings of the molecular mechanisms involved in the plausible role of RBPs in RNA processing in neurodegenerative disease is discussed.
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Affiliation(s)
- Andrea Ocharán-Mercado
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Jaqueline Loaeza-Loaeza
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Yaneth Castro-Coronel
- Laboratorio de Epigenética del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas 88, Chilpancingo, Guerrero, 39086, México
| | - Leonor C Acosta-Saavedra
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Luisa C Hernández-Kelly
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México
| | - Daniel Hernández-Sotelo
- Laboratorio de Epigenética del Cáncer, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas 88, Chilpancingo, Guerrero, 39086, México
| | - Arturo Ortega
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, San Pedro Zacatenco, 07300 CDMX, México.
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13
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Zhang J, Fang Z, Song C. Molecular characteristics and clinical implications of serine/arginine-rich splicing factors in human cancer. Aging (Albany NY) 2023; 15:13287-13311. [PMID: 38015716 DOI: 10.18632/aging.205241] [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: 07/17/2023] [Accepted: 10/17/2023] [Indexed: 11/30/2023]
Abstract
As critical splicing regulators, serine/arginine-rich splicing factors (SRSFs) play pivotal roles in carcinogenesis. As dysregulation of SRSFs may confer potential cancer risks, targeting SRSFs could provide important insights into cancer therapy. However, a global and comprehensive pattern to elaborate the molecular characteristics, mechanisms, and clinical links of SRSFs in a wide variety of human cancer is still lacking. In this study, a systematic analysis was conducted to reveal the molecular characteristics and clinical implications of SRSFs covering more than 10000 tumour samples of 33 human cancer types. We found that SRSFs experienced prevalent genomic alterations and expression perturbations in multiple cancer types. The DNA methylation, m6A modification, and miRNA regulation of SRSFs were all cancer context-dependent. Importantly, we found that SRSFs were strongly associated with cancer immunity, and were capable of predicting response to immunotherapy. And SRSFs had colossal potential for predicting survival in multiple cancer types, including those that have received immunotherapy. Moreover, we also found that SRSFs could indicate the drug sensitivity of targeted therapy and chemotherapy. Our research highlights the significance of SRSFs in cancer occurrence and development, and provides sufficient resources for understanding the biological characteristics of SRSFs, offering a new and unique perspective for developing cancer therapeutic strategies.
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Affiliation(s)
- Jinjin Zhang
- Department of Emergency Medicine, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Zhicheng Fang
- Department of Emergency Medicine, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Congkuan Song
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, China
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14
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Yu Z, Huang X, Wen S, Cao H, Wang N, Shen S, Ding M. Alternative Splicing under Cold Stress in Paper Mulberry. PLANTS (BASEL, SWITZERLAND) 2023; 12:3950. [PMID: 38068587 PMCID: PMC10707748 DOI: 10.3390/plants12233950] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 05/19/2024]
Abstract
The paper mulberry is a commonly found tree species with a long history of cultivation. It also serves as a crucial case study for understanding how woody plants adapt to low temperatures. Under cold treatment, we observed a substantial number of alternative splicing (AS) genes, showcasing the intricate landscape of AS events. We have detected all seven types of AS events, with the alternative 3' splice site (A3) having the most. We observed that many genes that underwent differential AS were significantly enriched in starch and sucrose metabolism and circadian rhythm pathways. Moreover, a considerable proportion of differentially spliced genes (DSGs) also showed differential expression, with 20.38% and 25.65% under 12 h and 24 h cold treatments, respectively. This suggests a coordinated regulation between gene AS and expression, playing a pivotal role in the paper mulberry's adaptation to cold stress. We further investigated the regulatory mechanisms of AS, identifying 41 serine/arginine-rich (SR) splicing factors, among which 11 showed differential expression under cold treatment, while 29 underwent alternative splicing. Additionally, genes undergoing AS displayed significantly higher DNA methylation levels under cold stress, while normal splicing (non-AS) genes exhibited relatively lower methylation levels. These findings suggest that methylation may play an important role in governing gene AS. Finally, our research will provide useful information on the role of AS in the cold acclimation tolerance of the paper mulberry.
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Affiliation(s)
- Zhipeng Yu
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Linan, Hangzhou 311300, China; (Z.Y.); (X.H.); (S.W.); (H.C.); (N.W.)
| | - Xia Huang
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Linan, Hangzhou 311300, China; (Z.Y.); (X.H.); (S.W.); (H.C.); (N.W.)
| | - Shuhan Wen
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Linan, Hangzhou 311300, China; (Z.Y.); (X.H.); (S.W.); (H.C.); (N.W.)
| | - Haijuan Cao
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Linan, Hangzhou 311300, China; (Z.Y.); (X.H.); (S.W.); (H.C.); (N.W.)
| | - Nan Wang
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Linan, Hangzhou 311300, China; (Z.Y.); (X.H.); (S.W.); (H.C.); (N.W.)
| | - Shihua Shen
- State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Mingquan Ding
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Linan, Hangzhou 311300, China; (Z.Y.); (X.H.); (S.W.); (H.C.); (N.W.)
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15
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Shah K, He S, Turner DJ, Corbo J, Rebbani K, Bateman JM, Cheloufi S, Igreja C, Valkov E, Murn J. A paradigm for regulation at the effector interface with RNA-binding proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.558714. [PMID: 37790431 PMCID: PMC10542489 DOI: 10.1101/2023.09.20.558714] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
RNA-binding proteins (RBPs) are key regulators of gene expression, but how RBPs convey regulatory instructions to the core effectors of RNA processing is unclear. Here we document the existence and functions of a multivalent RBP-effector interface. We show that the effector interface of a deeply conserved RBP with an essential role in metazoan development, Unkempt, is mediated by a novel type of 'dual-purpose' peptide motifs that can contact two different surfaces of interacting proteins. Unexpectedly, we find that the multivalent contacts do not merely serve effector recruitment but are required for the accuracy of RNA recognition by the recruiting RBP. Systems analyses reveal that multivalent RBP-effector contacts can repurpose the principal activity of an effector for a different function, as we demonstrate for reuse of the central eukaryotic mRNA decay factor CCR4-NOT in translational control. Our study establishes the molecular assembly and functional principles of an RBP-effector interface, with implications for the evolution and function of RBP-operated regulatory networks.
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Affiliation(s)
- Kriti Shah
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA 92521, U.S.A
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA 92521, U.S.A
- These authors contributed equally
| | - Shiyang He
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA 92521, U.S.A
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA 92521, U.S.A
- These authors contributed equally
| | - David J. Turner
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, U.S.A
- These authors contributed equally
| | - Joshua Corbo
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, U.S.A
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, U.S.A
| | - Khadija Rebbani
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, U.S.A
| | - Joseph M. Bateman
- Maurice Wohl Clinical Neuroscience Institute, King’s College London, 5 Cutcombe Road, London, SE5 9RX, U.K
| | - Sihem Cheloufi
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA 92521, U.S.A
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA 92521, U.S.A
- Stem Cell Center, University of California, Riverside, 900 University Ave, Riverside, CA 92521, U.S.A
| | - Cátia Igreja
- Department for Integrative Evolutionary Biology, Max-Planck-Ring 9, D-72076 Tübingen, Germany
| | - Eugene Valkov
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, U.S.A
| | - Jernej Murn
- Department of Biochemistry, University of California, Riverside, 3401 Watkins Drive, Boyce Hall, Riverside, CA 92521, U.S.A
- Center for RNA Biology and Medicine, 900 University Ave, Riverside, CA 92521, U.S.A
- Lead contact
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Farshadyeganeh P, Nazim M, Zhang R, Ohkawara B, Nakajima K, Rahman MA, Nasrin F, Ito M, Takeda JI, Ohe K, Miyasaka Y, Ohno T, Masuda A, Ohno K. Splicing regulation of GFPT1 muscle-specific isoform and its roles in glucose metabolisms and neuromuscular junction. iScience 2023; 26:107746. [PMID: 37744035 PMCID: PMC10514471 DOI: 10.1016/j.isci.2023.107746] [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: 05/10/2023] [Revised: 07/29/2023] [Accepted: 08/24/2023] [Indexed: 09/26/2023] Open
Abstract
Glutamine:fructose-6-phosphate transaminase 1 (GFPT1) is the rate-limiting enzyme of the hexosamine biosynthetic pathway (HBP). A 54-bp exon 9 of GFPT1 is specifically included in skeletal and cardiac muscles to generate a long isoform of GFPT1 (GFPT1-L). We showed that SRSF1 and Rbfox1/2 cooperatively enhance, and hnRNP H/F suppresses, the inclusion of human GFPT1 exon 9 by modulating recruitment of U1 snRNP. Knockout (KO) of GFPT1-L in skeletal muscle markedly increased the amounts of GFPT1 and UDP-HexNAc, which subsequently suppressed the glycolytic pathway. Aged KO mice showed impaired insulin-mediated glucose uptake, as well as muscle weakness and fatigue likely due to abnormal formation and maintenance of the neuromuscular junction. Taken together, GFPT1-L is likely to be acquired in evolution in mammalian striated muscles to attenuate the HBP for efficient glycolytic energy production, insulin-mediated glucose uptake, and the formation and maintenance of the neuromuscular junction.
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Affiliation(s)
- Paniz Farshadyeganeh
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Mohammad Nazim
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ruchen Zhang
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Kazuki Nakajima
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu 501-1193, Japan
| | - Mohammad Alinoor Rahman
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Biochemistry and Molecular Biology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, USA
| | - Farhana Nasrin
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Biochemistry and Molecular Biology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, USA
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Jun-ichi Takeda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Kenji Ohe
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180, Japan
| | - Yuki Miyasaka
- Division of Experimental Animals, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Tamio Ohno
- Division of Experimental Animals, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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17
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Li Z, Wei H, Hu D, Li X, Guo Y, Ding X, Guo H, Zhang L. Research Progress on the Structural and Functional Roles of hnRNPs in Muscle Development. Biomolecules 2023; 13:1434. [PMID: 37892116 PMCID: PMC10604023 DOI: 10.3390/biom13101434] [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: 09/04/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023] Open
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a superfamily of RNA-binding proteins consisting of more than 20 members. These proteins play a crucial role in various biological processes by regulating RNA splicing, transcription, and translation through their binding to RNA. In the context of muscle development and regeneration, hnRNPs are involved in a wide range of regulatory mechanisms, including alternative splicing, transcription regulation, miRNA regulation, and mRNA stability regulation. Recent studies have also suggested a potential association between hnRNPs and muscle-related diseases. In this report, we provide an overview of our current understanding of how hnRNPs regulate RNA metabolism and emphasize the significance of the key members of the hnRNP family in muscle development. Furthermore, we explore the relationship between the hnRNP family and muscle-related diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Linlin Zhang
- Key Laboratory of Animal Breeding and Healthy Livestock Farming, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin 300392, China; (Z.L.); (H.W.); (D.H.); (X.L.); (Y.G.); (X.D.); (H.G.)
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18
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Jiang T, Wang L, Tang L, Zeb A, Hou Y. Identification of two short peptide motifs from serine/arginine-rich protein ribonucleic acid recognition motif-1 domain acting as splicing regulators. PeerJ 2023; 11:e16103. [PMID: 37744237 PMCID: PMC10512959 DOI: 10.7717/peerj.16103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023] Open
Abstract
Background Serine/arginine-rich (SR) proteins regulate pre-mRNA splicing. However, structurally similar proteins often behave differently in splicing regulation and the underlying mechanisms are largely unknown. Here, using SMN1/2 minigenes we extensively analyzed four SR proteins, SRSF1/5/6/9. Methods In this study, the effects of these proteins on SMN1/2 exon 7 splicing when tethered at either intron 6 or 7 were evaluated using an MS2-tethering assay. Deletion analysis in four SR proteins and co-overexpression analysis were performed. Results Splicing outcomes varied among all four SR proteins, SRSF1 and SRSF5 function the same at the two sites, acting as repressor and stimulator, respectively; while SRSF6 and SRSF9 promote exon 7 inclusion at only one site. Further, the key domains of each SR proteins were investigated, which identified a potent inhibitory nonapeptide in the C-terminus of SRSF1/9 ribonucleic acid recognition motif-1 (RRM1) and a potent stimulatory heptapeptide at the N-terminus of SRSF5/6 RRM1. Conclusion The insight of the four SR proteins and their domains in affecting SMN gene splicing brings a new perspective on the modes of action of SR proteins; and the functional peptides obtained here offers new ideas for developing splice switching-related therapies.
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Affiliation(s)
- Tao Jiang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
- Department of Rehabilitation, Southwest Hospital, Third Military Medical University Army Medical University, Chongqing, China
| | - Li Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Liang Tang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Azhar Zeb
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Yanjun Hou
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
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19
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Rodriguez Gallo MC, Uhrig RG. Phosphorylation mediated regulation of RNA splicing in plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1249057. [PMID: 37780493 PMCID: PMC10539000 DOI: 10.3389/fpls.2023.1249057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/22/2023] [Indexed: 10/03/2023]
Abstract
For the past two decades, the study of alternative splicing (AS) and its involvement in plant development and stress response has grown in popularity. Only recently however, has the focus shifted to the study of how AS regulation (or lack-thereof) affects downstream mRNA and protein landscapes and how these AS regulatory events impact plant development and stress tolerance. In humans, protein phosphorylation represents one of the predominant mechanisms by which AS is regulated and thus the protein kinases governing these phosphorylation events are of interest for further study. Large-scale phosphoproteomic studies in plants have consistently found that RNA splicing-related proteins are extensively phosphorylated, however, the signaling pathways involved in AS regulation have not been resolved. In this mini-review, we summarize our current knowledge of the three major splicing-related protein kinase families in plants that are suggested to mediate AS phospho-regulation and draw comparisons to their metazoan orthologs. We also summarize and contextualize the phosphorylation events identified as occurring on splicing-related protein families to illustrate the high degree to which splicing-related proteins are modified, placing a new focus on elucidating the impacts of AS at the protein and PTM-level.
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Affiliation(s)
| | - R. Glen Uhrig
- University of Alberta, Department of Biological Sciences, Edmonton, AB, Canada
- University of Alberta, Department of Biochemistry, Edmonton, AB, Canada
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20
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Ghosh A, Chakraborty P, Biswas D. Fine tuning of the transcription juggernaut: A sweet and sour saga of acetylation and ubiquitination. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194944. [PMID: 37236503 DOI: 10.1016/j.bbagrm.2023.194944] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/26/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023]
Abstract
Among post-translational modifications of proteins, acetylation, phosphorylation, and ubiquitination are most extensively studied over the last several decades. Owing to their different target residues for modifications, cross-talk between phosphorylation with that of acetylation and ubiquitination is relatively less pronounced. However, since canonical acetylation and ubiquitination happen only on the lysine residues, an overlap of the same lysine residue being targeted for both acetylation and ubiquitination happens quite frequently and thus plays key roles in overall functional regulation predominantly through modulation of protein stability. In this review, we discuss the cross-talk of acetylation and ubiquitination in the regulation of protein stability for the functional regulation of cellular processes with an emphasis on transcriptional regulation. Further, we emphasize our understanding of the functional regulation of Super Elongation Complex (SEC)-mediated transcription, through regulation of stabilization by acetylation, deacetylation and ubiquitination and associated enzymes and its implication in human diseases.
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Affiliation(s)
- Avik Ghosh
- Laboratory of Transcription Biology Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Poushali Chakraborty
- Laboratory of Transcription Biology Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India.
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21
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Ellis JA, Hale MA, Cleary JD, Wang E, Andrew Berglund J. Alternative splicing outcomes across an RNA-binding protein concentration gradient. J Mol Biol 2023:168156. [PMID: 37230319 DOI: 10.1016/j.jmb.2023.168156] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/18/2023] [Accepted: 05/17/2023] [Indexed: 05/27/2023]
Abstract
Alternative splicing (AS) is a dynamic RNA processing step that produces multiple RNA isoforms from a single pre-mRNA transcript and contributes to the complexity of the cellular transcriptome and proteome. This process is regulated through a network of cis-regulatory sequence elements and trans-acting factors, most-notably RNA binding proteins (RBPs). The muscleblind-like (MBNL) and RNA binding fox-1 homolog (RBFOX) are two well characterized families of RBPs that regulate fetal to adult AS transitions critical for proper muscle, heart, and central nervous system development. To better understand how the concentration of these RBPs influences AS transcriptome wide, we engineered a MBNL1 and RBFOX1 inducible HEK-293 cell line. Modest induction of exogenous RBFOX1 in this cell line modulated MBNL1-dependent AS outcomes in 3 skipped exon events, despite significant levels of endogenous RBFOX1 and RBFOX2. Due to background RBFOX levels, we conducted a focused analysis of dose-dependent MBNL1 skipped exon AS outcomes and generated transcriptome wide dose-response curves. Analysis of this data demonstrates that MBNL1-regulated exclusion events may require higher concentrations of MBNL1 protein to properly regulate AS outcomes compared to inclusion events and that multiple arrangements of YGCY motifs can produce similar splicing outcomes. These results suggest that rather than a simple relationship between the organization of RBP binding sites and a specific splicing outcome, that complex interaction networks govern both AS inclusion and exclusion events across a RBP gradient.
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Affiliation(s)
- Joseph A Ellis
- Department of Biochemistry & Molecular Biology & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States; The RNA Institute, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States
| | - Melissa A Hale
- Department of Biochemistry & Molecular Biology & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States; Department of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - John D Cleary
- The RNA Institute, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States
| | - Eric Wang
- Department of Microbiology and Molecular Genetics & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - J Andrew Berglund
- Department of Biochemistry & Molecular Biology & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States; The RNA Institute, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States; Department of Biological Sciences, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States; RNA Institute, State University of New York at Albany, LSRB-2033, 1400 Washington Avenue, Albany, New York, 12222.
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22
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Lyu M, Lai H, Wang Y, Zhou Y, Chen Y, Wu D, Chen J, Ying B. Roles of alternative splicing in infectious diseases: from hosts, pathogens to their interactions. Chin Med J (Engl) 2023; 136:767-779. [PMID: 36893312 PMCID: PMC10150853 DOI: 10.1097/cm9.0000000000002621] [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: 11/09/2022] [Indexed: 03/11/2023] Open
Abstract
ABSTRACT Alternative splicing (AS) is an evolutionarily conserved mechanism that removes introns and ligates exons to generate mature messenger RNAs (mRNAs), extremely improving the richness of transcriptome and proteome. Both mammal hosts and pathogens require AS to maintain their life activities, and inherent physiological heterogeneity between mammals and pathogens makes them adopt different ways to perform AS. Mammals and fungi conduct a two-step transesterification reaction by spliceosomes to splice each individual mRNA (named cis -splicing). Parasites also use spliceosomes to splice, but this splicing can occur among different mRNAs (named trans -splicing). Bacteria and viruses directly hijack the host's splicing machinery to accomplish this process. Infection-related changes are reflected in the spliceosome behaviors and the characteristics of various splicing regulators (abundance, modification, distribution, movement speed, and conformation), which further radiate to alterations in the global splicing profiles. Genes with splicing changes are enriched in immune-, growth-, or metabolism-related pathways, highlighting approaches through which hosts crosstalk with pathogens. Based on these infection-specific regulators or AS events, several targeted agents have been developed to fight against pathogens. Here, we summarized recent findings in the field of infection-related splicing, including splicing mechanisms of pathogens and hosts, splicing regulation and aberrant AS events, as well as emerging targeted drugs. We aimed to systemically decode host-pathogen interactions from a perspective of splicing. We further discussed the current strategies of drug development, detection methods, analysis algorithms, and database construction, facilitating the annotation of infection-related splicing and the integration of AS with disease phenotype.
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Affiliation(s)
- Mengyuan Lyu
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Hongli Lai
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Yili Wang
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Yanbing Zhou
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Yi Chen
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Dongsheng Wu
- Department of Thoracic Surgery and Institute of Thoracic Oncology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Jie Chen
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Binwu Ying
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
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23
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Fackenthal JD. Alternative mRNA Splicing and Promising Therapies in Cancer. Biomolecules 2023; 13:biom13030561. [PMID: 36979496 PMCID: PMC10046298 DOI: 10.3390/biom13030561] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/09/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Cancer is among the leading causes of mortality worldwide. While considerable attention has been given to genetic and epigenetic sources of cancer-specific cellular activities, the role of alternative mRNA splicing has only recently received attention as a major contributor to cancer initiation and progression. The distribution of alternate mRNA splicing variants in cancer cells is different from their non-cancer counterparts, and cancer cells are more sensitive than non-cancer cells to drugs that target components of the splicing regulatory network. While many of the alternatively spliced mRNAs in cancer cells may represent "noise" from splicing dysregulation, certain recurring splicing variants have been shown to contribute to tumor progression. Some pathogenic splicing disruption events result from mutations in cis-acting splicing regulatory sequences in disease-associated genes, while others may result from shifts in balance among naturally occurring alternate splicing variants among mRNAs that participate in cell cycle progression and the regulation of apoptosis. This review provides examples of cancer-related alternate splicing events resulting from each step of mRNA processing and the promising therapies that may be used to address them.
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Affiliation(s)
- James D Fackenthal
- Department of Biological Sciences, College of Science and Health, Benedictine University, Lisle, IL 60532, USA
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24
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Ye R, Hu N, Cao C, Su R, Xu S, Yang C, Zhou X, Xue Y. Capture RIC-seq reveals positional rules of PTBP1-associated RNA loops in splicing regulation. Mol Cell 2023; 83:1311-1327.e7. [PMID: 36958328 DOI: 10.1016/j.molcel.2023.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/10/2023] [Accepted: 02/27/2023] [Indexed: 03/25/2023]
Abstract
RNA-binding proteins (RBPs) bind at different positions of the pre-mRNA molecules to promote or reduce the usage of a particular exon. Seeking to understand the working principle of these positional effects, we develop a capture RIC-seq (CRIC-seq) method to enrich specific RBP-associated in situ proximal RNA-RNA fragments for deep sequencing. We determine hnRNPA1-, SRSF1-, and PTBP1-associated proximal RNA-RNA contacts and regulatory mechanisms in HeLa cells. Unexpectedly, the 3D RNA map analysis shows that PTBP1-associated loops in individual introns preferentially promote cassette exon splicing by accelerating asymmetric intron removal, whereas the loops spanning across cassette exon primarily repress splicing. These "positional rules" can faithfully predict PTBP1-regulated splicing outcomes. We further demonstrate that cancer-related splicing quantitative trait loci can disrupt RNA loops by reducing PTBP1 binding on pre-mRNAs to cause aberrant splicing in tumors. Our study presents a powerful method for exploring the functions of RBP-associated RNA-RNA proximal contacts in gene regulation and disease.
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Affiliation(s)
- Rong Ye
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Naijing Hu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changchang Cao
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ruibao Su
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shihan Xu
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Chen Yang
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Xiangtian Zhou
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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25
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Wang L, Gong S, Zhang X, Azhar Z, Chen J. Investigation of the regulatory effects of synthesized antisense oligonucleotides on androgen receptor (AR) exon 3 splicing in prostate cancer cells. Gene 2023; 866:147330. [PMID: 36871670 DOI: 10.1016/j.gene.2023.147330] [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: 11/30/2022] [Revised: 02/10/2023] [Accepted: 02/28/2023] [Indexed: 03/07/2023]
Abstract
The Androgen Receptor (AR) gene plays a key role in castration-resistant prostate cancer (CRPC). Controlling the progression of CRPC by inhibiting AR gene expression is one of the core directions for prostate cancer (Pca) drug development. A 23-amino acids retention, named exon 3a, into the DNA binding domain of the splice variant AR23 has been shown to prevent AR from entering the nucleus and restore the sensitivity of cancer cells to related therapies. In this study, we conducted a preliminary investigation of the splicing modulation of the AR gene in order to develop a splice-switching therapy for Pca by promoting exon 3a inclusion. Using mutagenesis-coupled RT-PCR with AR minigene and over-expression of certain splicing factors, we found that serine/arginine-rich (SR) proteins are key factors facilitating the recognition of the 3' splice site of exon 3a (L-3' SS), while the deletion or blocking of the polypyrimidine tract (PPT) region of the original 3' splice site of exon 3 (S-3' SS) could strongly enhance exon 3a splicing without affecting the function of any SR protein. Furthermore, we designed a series of antisense oligonucleotides (ASOs) to screen drug candidates, and ASOs targeting S-3' SS and its PPT region or the exonic region of exon 3 turned out to be most effective in rescuing exon 3a splicing. A dose-response test indicated ASO12 as the lead candidate drug significantly promoting the inclusion of exon 3a to more than 85%. MTT assay confirmed that the cell proliferation was significantly inhibited after ASO treatment. Our results provide the first glance to AR splicing regulation. With several promising therapeutic ASO candidates obtained here, further development of ASO drugs to treat CRPC is strongly encouraged.
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Affiliation(s)
- Li Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China.
| | - Shuaishuai Gong
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Xi Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Zeb Azhar
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Jialin Chen
- Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China.
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26
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Esser LM, Schmitz K, Hillebrand F, Erkelenz S, Schaal H, Stork B, Grimmler M, Wesselborg S, Peter C. Phosphorylation of pICln by the autophagy activating kinase ULK1 regulates snRNP biogenesis and splice activity of the cell. Comput Struct Biotechnol J 2023; 21:2100-2109. [PMID: 36968021 PMCID: PMC10034211 DOI: 10.1016/j.csbj.2023.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/18/2023] Open
Abstract
The spliceosome, responsible for all mature protein-coding transcripts of eukaryotic intron-containing genes, consists of small uridine-rich nuclear ribonucleoproteins (UsnRNPs). The assembly of UsnRNPs depends, on one hand, on the arginine methylation of Sm proteins catalyzed by the PRMT5 complex. On the other hand, it depends on the phosphorylation of the PRMT5 subunit pICln by the Uncoordinated Like Kinase 1 (ULK1). In consequence, phosphorylation of pICln affects the stability of the UsnRNP assembly intermediate, the so-called 6 S complex. The detailed mechanisms of phosphorylation-dependent integrity and subsequent UsnRNP assembly of the 6 S complex in vivo have not yet been analyzed. By using a phospho-specific antibody against ULK1-dependent phosphorylation sites of pICln, we visualize the intracellular distribution of phosphorylated pICln. Furthermore, we detect the colocaliphosphor-pICln1 with phospho-pICln by size-exclusion chromatography and immunofluorescence techniques. We also show that phosphorylated pICln is predominantly present in the 6 S complex. The addition of ULK1 to in vitro produced 6 S complex, as well as the reconstitution of ULK1 in ULK1-deficient cells, increases the efficiency of snRNP biogenesis. Accordingly, inhibition of ULK1 and the associated decreased pICln phosphorylation lead to accumulation of the 6 S complex and reduction in the spliceosomal activity of the cell.
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27
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Horn T, Gosliga A, Li C, Enculescu M, Legewie S. Position-dependent effects of RNA-binding proteins in the context of co-transcriptional splicing. NPJ Syst Biol Appl 2023; 9:1. [PMID: 36653378 PMCID: PMC9849329 DOI: 10.1038/s41540-022-00264-3] [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: 06/21/2021] [Accepted: 12/08/2022] [Indexed: 01/19/2023] Open
Abstract
Alternative splicing is an important step in eukaryotic mRNA pre-processing which increases the complexity of gene expression programs, but is frequently altered in disease. Previous work on the regulation of alternative splicing has demonstrated that splicing is controlled by RNA-binding proteins (RBPs) and by epigenetic DNA/histone modifications which affect splicing by changing the speed of polymerase-mediated pre-mRNA transcription. The interplay of these different layers of splicing regulation is poorly understood. In this paper, we derived mathematical models describing how splicing decisions in a three-exon gene are made by combinatorial spliceosome binding to splice sites during ongoing transcription. We additionally take into account the effect of a regulatory RBP and find that the RBP binding position within the sequence is a key determinant of how RNA polymerase velocity affects splicing. Based on these results, we explain paradoxical observations in the experimental literature and further derive rules explaining why the same RBP can act as inhibitor or activator of cassette exon inclusion depending on its binding position. Finally, we derive a stochastic description of co-transcriptional splicing regulation at the single-cell level and show that splicing outcomes show little noise and follow a binomial distribution despite complex regulation by a multitude of factors. Taken together, our simulations demonstrate the robustness of splicing outcomes and reveal that quantitative insights into kinetic competition of co-transcriptional events are required to fully understand this important mechanism of gene expression diversity.
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Affiliation(s)
- Timur Horn
- grid.424631.60000 0004 1794 1771Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Alison Gosliga
- grid.424631.60000 0004 1794 1771Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany ,grid.5719.a0000 0004 1936 9713University of Stuttgart, Department of Systems Biology and Stuttgart Research Center Systems Biology (SRCSB), Allmandring 31, 70569 Stuttgart, Germany
| | - Congxin Li
- grid.5719.a0000 0004 1936 9713University of Stuttgart, Department of Systems Biology and Stuttgart Research Center Systems Biology (SRCSB), Allmandring 31, 70569 Stuttgart, Germany
| | - Mihaela Enculescu
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany.
| | - Stefan Legewie
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany. .,University of Stuttgart, Department of Systems Biology and Stuttgart Research Center Systems Biology (SRCSB), Allmandring 31, 70569, Stuttgart, Germany.
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28
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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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29
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Sertznig H, Roesmann F, Wilhelm A, Heininger D, Bleekmann B, Elsner C, Santiago M, Schuhenn J, Karakoese Z, Benatzy Y, Snodgrass R, Esser S, Sutter K, Dittmer U, Widera M. SRSF1 acts as an IFN-I-regulated cellular dependency factor decisively affecting HIV-1 post-integration steps. Front Immunol 2022; 13:935800. [PMID: 36458014 PMCID: PMC9706209 DOI: 10.3389/fimmu.2022.935800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/19/2022] [Indexed: 08/24/2023] Open
Abstract
Efficient HIV-1 replication depends on balanced levels of host cell components including cellular splicing factors as the family of serine/arginine-rich splicing factors (SRSF, 1-10). Type I interferons (IFN-I) play a crucial role in the innate immunity against HIV-1 by inducing the expression of IFN-stimulated genes (ISGs) including potent host restriction factors. The less well known IFN-repressed genes (IRepGs) might additionally affect viral replication by downregulating host dependency factors that are essential for the viral life cycle; however, so far, the knowledge about IRepGs involved in HIV-1 infection is very limited. In this work, we could demonstrate that HIV-1 infection and the associated ISG induction correlated with low SRSF1 levels in intestinal lamina propria mononuclear cells (LPMCs) and peripheral blood mononuclear cells (PBMCs) during acute and chronic HIV-1 infection. In HIV-1-susceptible cell lines as well as primary monocyte-derived macrophages (MDMs), expression levels of SRSF1 were transiently repressed upon treatment with specific IFNα subtypes in vitro. Mechanically, 4sU labeling of newly transcribed mRNAs revealed that IFN-mediated SRSF1 repression is regulated on early RNA level. SRSF1 knockdown led to an increase in total viral RNA levels, but the relative proportion of the HIV-1 viral infectivity factor (Vif) coding transcripts, which is essential to counteract APOBEC3G-mediated host restriction, was significantly reduced. In the presence of high APOBEC3G levels, however, increased LTR activity upon SRSF1 knockdown facilitated the overall replication, despite decreased vif mRNA levels. In contrast, SRSF1 overexpression significantly impaired HIV-1 post-integration steps including LTR transcription, alternative splice site usage, and virus particle production. Since balanced SRSF1 levels are crucial for efficient viral replication, our data highlight the so far undescribed role of SRSF1 acting as an IFN-modulated cellular dependency factor decisively regulating HIV-1 post-integration steps.
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Affiliation(s)
- Helene Sertznig
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Fabian Roesmann
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Alexander Wilhelm
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Delia Heininger
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Barbara Bleekmann
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Carina Elsner
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Mario Santiago
- Department of Medicine, University of Colorado Denver, Aurora, CO, United States
| | - Jonas Schuhenn
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Zehra Karakoese
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Yvonne Benatzy
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Ryan Snodgrass
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Stefan Esser
- Clinic of Dermatology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Kathrin Sutter
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Ulf Dittmer
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Marek Widera
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
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30
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Qiu J, Qu R, Lin M, Xu J, Zhu Q, Zhang Z, Sun J. Position-dependent effects of hnRNP A1/A2 in SMN1/2 exon7 splicing. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - GENE REGULATORY MECHANISMS 2022; 1865:194875. [DOI: 10.1016/j.bbagrm.2022.194875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/08/2022] [Accepted: 09/28/2022] [Indexed: 11/07/2022]
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31
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Shilo A, Pegoraro G, Misteli T. HiFENS: high-throughput FISH detection of endogenous pre-mRNA splicing isoforms. Nucleic Acids Res 2022; 50:e130. [PMID: 36243969 PMCID: PMC9825148 DOI: 10.1093/nar/gkac869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/01/2022] [Accepted: 09/27/2022] [Indexed: 01/29/2023] Open
Abstract
Splicing factors play an essential role in regulation of alternative pre-mRNA splicing. While much progress has been made in delineating the mechanisms of the splicing machinery, the identity of signal transduction pathways and upstream factors that regulate splicing factor activity is largely unknown. A major challenge in the discovery of upstream regulatory factors of pre-mRNA splicing is the scarcity of functional genomics screening methods to monitor splicing outcomes of endogenous genes. Here, we have developed HiFENS (high throughput FISH detection of endogenous splicing isoforms), a high-throughput imaging assay based on hybridization chain reaction (HCR) and used HiFENS to screen for cellular factors that regulate alternative splicing of endogenous genes. We demonstrate optimized detection with high specificity of endogenous splicing isoforms and multiplexing of probes for accurate detection of splicing outcomes with single cell resolution. As proof-of-principle, we perform an RNAi screen of 702 human kinases and identify potential candidate upstream splicing regulators of the FGFR2 gene. HiFENS should be a useful tool for the unbiased delineation of cellular pathways involved in alternative splicing regulation.
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Affiliation(s)
- Asaf Shilo
- Cell Biology of Genomes, Center for Cancer Research (CCR), National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Gianluca Pegoraro
- High-Throughput Imaging Facility (HiTIF), Center for Cancer Research (CCR), National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Tom Misteli
- To whom correspondence should be addressed. Tel: +1 240 670 6669; Fax: +1 240 670 6670;
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32
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Yang L, Yang L, Zhao C, Liu J, Tong C, Zhang Y, Cheng X, Jiang H, Shen J, Xie M, Liu S. Differential alternative splicing genes and isoform co-expression networks of Brassica napus under multiple abiotic stresses. FRONTIERS IN PLANT SCIENCE 2022; 13:1009998. [PMID: 36311064 PMCID: PMC9608124 DOI: 10.3389/fpls.2022.1009998] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Alternative splicing (AS) is an important regulatory process that affects plant development and stress responses by greatly increasing the complexity of transcriptome and proteome. To understand how the AS landscape of B. napus changes in response to abiotic stresses, we investigated 26 RNA-seq libraries, including control and treatments with cold, dehydration, salt, and abscisic acid (ABA) at two different time points, to perform comparative alternative splicing analysis. Apparently, AS events increased under all stresses except dehydration for 1 h, and intron retention was the most common AS mode. In addition, a total of 357 differential alternative splicing (DAS) genes were identified under four abiotic stresses, among which 81 DAS genes existed in at least two stresses, and 276 DAS genes were presented under only one stress. A weighted gene co-expression network analysis (WGCNA) based on the splicing isoforms, rather than the genes, pinpointed out 23 co-expression modules associated with different abiotic stresses. Among them, a number of significant hub genes were also found to be DAS genes, which encode key isoforms involved in responses to single stress or multiple stresses, including RNA-binding proteins, transcription factors, and other important genes, such as RBP45C, LHY, MYB59, SCL30A, RS40, MAJ23.10, and DWF4. The splicing isoforms of candidate genes identified in this study could be a valuable resource for improving tolerance of B. napus against multiple abiotic stresses.
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Affiliation(s)
- Lingli Yang
- National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Li Yang
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
- Biosystematics Group, Wageningen University and Research, Wageningen, Netherlands
| | - Chuanji Zhao
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Jie Liu
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Chaobo Tong
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Yuanyuan Zhang
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Xiaohui Cheng
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Huifang Jiang
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Jinxiong Shen
- National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Meili Xie
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Shengyi Liu
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
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33
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Müller L, Ptok J, Nisar A, Antemann J, Grothmann R, Hillebrand F, Brillen AL, Ritchie A, Theiss S, Schaal H. Modeling splicing outcome by combining 5'ss strength and splicing regulatory elements. Nucleic Acids Res 2022; 50:8834-8851. [PMID: 35947702 PMCID: PMC9410876 DOI: 10.1093/nar/gkac663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 06/23/2022] [Accepted: 07/27/2022] [Indexed: 12/24/2022] Open
Abstract
Correct pre-mRNA processing in higher eukaryotes vastly depends on splice site recognition. Beyond conserved 5'ss and 3'ss motifs, splicing regulatory elements (SREs) play a pivotal role in this recognition process. Here, we present in silico designed sequences with arbitrary a priori prescribed splicing regulatory HEXplorer properties that can be concatenated to arbitrary length without changing their regulatory properties. We experimentally validated in silico predictions in a massively parallel splicing reporter assay on more than 3000 sequences and exemplarily identified some SRE binding proteins. Aiming at a unified 'functional splice site strength' encompassing both U1 snRNA complementarity and impact from neighboring SREs, we developed a novel RNA-seq based 5'ss usage landscape, mapping the competition of pairs of high confidence 5'ss and neighboring exonic GT sites along HBond and HEXplorer score coordinate axes on human fibroblast and endothelium transcriptome datasets. These RNA-seq data served as basis for a logistic 5'ss usage prediction model, which greatly improved discrimination between strong but unused exonic GT sites and annotated highly used 5'ss. Our 5'ss usage landscape offers a unified view on 5'ss and SRE neighborhood impact on splice site recognition, and may contribute to improved mutation assessment in human genetics.
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Affiliation(s)
| | | | - Azlan Nisar
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany,Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, August-Schmidt-Ring 10, Recklinghausen 45665, Germany
| | - Jennifer Antemann
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Ramona Grothmann
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Frank Hillebrand
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Anna-Lena Brillen
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Anastasia Ritchie
- Institute of Virology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | | | - Heiner Schaal
- To whom correspondence should be addressed. Tel: +49 211 81 12393; Fax: +49 211 81 10856;
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Pan YJ, Liu BW, Pei DS. The Role of Alternative Splicing in Cancer: Regulatory Mechanism, Therapeutic Strategy, and Bioinformatics Application. DNA Cell Biol 2022; 41:790-809. [PMID: 35947859 DOI: 10.1089/dna.2022.0322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
[Formula: see text] Alternative splicing (AS) can generate distinct transcripts and subsequent isoforms that play differential functions from the same pre-mRNA. Recently, increasing numbers of studies have emerged, unmasking the association between AS and cancer. In this review, we arranged AS events that are closely related to cancer progression and presented promising treatments based on AS for cancer therapy. Obtaining proliferative capacity, acquiring invasive properties, gaining angiogenic features, shifting metabolic ability, and getting immune escape inclination are all splicing events involved in biological processes. Spliceosome-targeted and antisense oligonucleotide technologies are two novel strategies that are hopeful in tumor therapy. In addition, bioinformatics applications based on AS were summarized for better prediction and elucidation of regulatory routines mingled in. Together, we aimed to provide a better understanding of complicated AS events associated with cancer biology and reveal AS a promising target of cancer treatment in the future.
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Affiliation(s)
- Yao-Jie Pan
- Department of Pathology, Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, China
| | - Bo-Wen Liu
- Department of General Surgery, Xuzhou Medical University, Xuzhou, China
| | - Dong-Sheng Pei
- Department of Pathology, Laboratory of Clinical and Experimental Pathology, Xuzhou Medical University, Xuzhou, China
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35
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Pengelly RJ, Bakhtiar D, Borovská I, Královičová J, Vořechovský I. Exonic splicing code and protein binding sites for calcium. Nucleic Acids Res 2022; 50:5493-5512. [PMID: 35474482 PMCID: PMC9177970 DOI: 10.1093/nar/gkac270] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/01/2022] [Accepted: 04/05/2022] [Indexed: 11/12/2022] Open
Abstract
Auxilliary splicing sequences in exons, known as enhancers (ESEs) and silencers (ESSs), have been subject to strong selection pressures at the RNA and protein level. The protein component of this splicing code is substantial, recently estimated at ∼50% of the total information within ESEs, but remains poorly understood. The ESE/ESS profiles were previously associated with the Irving-Williams (I-W) stability series for divalent metals, suggesting that the ESE/ESS evolution was shaped by metal binding sites. Here, we have examined splicing activities of exonic sequences that encode protein binding sites for Ca2+, a weak binder in the I-W affinity order. We found that predicted exon inclusion levels for the EF-hand motifs and for Ca2+-binding residues in nonEF-hand proteins were higher than for average exons. For canonical EF-hands, the increase was centred on the EF-hand chelation loop and, in particular, on Ca2+-coordinating residues, with a 1>12>3∼5>9 hierarchy in the 12-codon loop consensus and usage bias at codons 1 and 12. The same hierarchy but a lower increase was observed for noncanonical EF-hands, except for S100 proteins. EF-hand loops preferentially accumulated exon splits in two clusters, one located in their N-terminal halves and the other around codon 12. Using splicing assays and published crosslinking and immunoprecipitation data, we identify candidate trans-acting factors that preferentially bind conserved GA-rich motifs encoding negatively charged amino acids in the loops. Together, these data provide evidence for the high capacity of codons for Ca2+-coordinating residues to be retained in mature transcripts, facilitating their exon-level expansion during eukaryotic evolution.
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Affiliation(s)
- Reuben J Pengelly
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Dara Bakhtiar
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Ivana Borovská
- Slovak Academy of Sciences, Centre of Biosciences, 840 05 Bratislava, Slovak Republic
| | - Jana Královičová
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
- Slovak Academy of Sciences, Centre of Biosciences, 840 05 Bratislava, Slovak Republic
- Slovak Academy of Sciences, Institute of Zoology, 845 06 Bratislava, Slovak Republic
| | - Igor Vořechovský
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
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36
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Jobbins AM, Haberman N, Artigas N, Amourda C, Paterson HAB, Yu S, Blackford SJI, Montoya A, Dore M, Wang YF, Sardini A, Cebola I, Zuber J, Rashid ST, Lenhard B, Vernia S. Dysregulated RNA polyadenylation contributes to metabolic impairment in non-alcoholic fatty liver disease. Nucleic Acids Res 2022; 50:3379-3393. [PMID: 35293570 PMCID: PMC8989518 DOI: 10.1093/nar/gkac165] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/16/2022] [Accepted: 03/09/2022] [Indexed: 11/19/2022] Open
Abstract
Pre-mRNA processing is an essential mechanism for the generation of mature mRNA and the regulation of gene expression in eukaryotic cells. While defects in pre-mRNA processing have been implicated in a number of diseases their involvement in metabolic pathologies is still unclear. Here, we show that both alternative splicing and alternative polyadenylation, two major steps in pre-mRNA processing, are significantly altered in non-alcoholic fatty liver disease (NAFLD). Moreover, we find that Serine and Arginine Rich Splicing Factor 10 (SRSF10) binding is enriched adjacent to consensus polyadenylation motifs and its expression is significantly decreased in NAFLD, suggesting a role mediating pre-mRNA dysregulation in this condition. Consistently, inactivation of SRSF10 in mouse and human hepatocytes in vitro, and in mouse liver in vivo, was found to dysregulate polyadenylation of key metabolic genes such as peroxisome proliferator-activated receptor alpha (PPARA) and exacerbate diet-induced metabolic dysfunction. Collectively our work implicates dysregulated pre-mRNA polyadenylation in obesity-induced liver disease and uncovers a novel role for SRSF10 in this process.
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Affiliation(s)
- Andrew M Jobbins
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Nejc Haberman
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Natalia Artigas
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Christopher Amourda
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Helen A B Paterson
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Sijia Yu
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Samuel J I Blackford
- Department of Metabolism, Digestion & Reproduction, Imperial College London, London W12 0NN, UK
| | - Alex Montoya
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Marian Dore
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Yi-Fang Wang
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Alessandro Sardini
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Inês Cebola
- Section of Genetics and Genomics, Department of Metabolism, Digestion & Reproduction, Imperial College London, London W12 0NN, UK
| | - Johannes Zuber
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Sheikh Tamir Rashid
- Department of Metabolism, Digestion & Reproduction, Imperial College London, London W12 0NN, UK
| | - Boris Lenhard
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Santiago Vernia
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
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37
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A Novel, Apparently Silent Variant in MFSD8 Causes Neuronal Ceroid Lipofuscinosis with Marked Intrafamilial Variability. Int J Mol Sci 2022; 23:ijms23042271. [PMID: 35216386 PMCID: PMC8877174 DOI: 10.3390/ijms23042271] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Variants in MFSD8 can cause neuronal ceroid lipofuscinoses (NCLs) as well as nonsyndromic retinopathy. The mutation spectrum includes mainly missense and stop variants, but splice sites and frameshift variants have also been reported. To date, apparently synonymous substitutions have not been shown to cause MFSD8-associated diseases. We report two closely related subjects from a consanguineous Turkish family who presented classical features of NCLs but demonstrated marked intrafamilial variability in age at the onset and severity of symptoms. In fact, the difference in the onset of first neurologic symptoms was 15 years and that of ophthalmologic symptoms was 12 years. One subject presented an intellectual disability and a considerable cerebellar ataxia syndrome, while the other subject showed no intellectual disability and only a mild atactic syndrome. The diagnostic genetic testing of both subjects based on genome sequencing prioritized a novel, apparently synonymous variant in MFSD8, which was found in homozygosity in both subjects. The variant was not located within an integral part of the splice site consensus sequences. However, the bioinformatic analyses suggested that the mutant allele is more likely to cause exon skipping due to an altered ratio of exonic splice enhancer and silencer motifs. Exon skipping was confirmed in vitro by minigene assays and in vivo by RNA analysis from patient lymphocytes. The mutant transcript is predicted to result in a frameshift and, if translated, in a truncated protein. Synonymous variants are often given a low priority in genetic diagnostics because of their expected lack of functional impact. This study highlights the importance of investigating the impact of synonymous variants on splicing.
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38
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Cold Response Transcriptome Analysis of the Alternative Splicing Events Induced by the Cold Stress in D. catenatum. Int J Mol Sci 2022; 23:ijms23020981. [PMID: 35055168 PMCID: PMC8778272 DOI: 10.3390/ijms23020981] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/21/2021] [Accepted: 01/08/2022] [Indexed: 02/07/2023] Open
Abstract
Dendrobium catenatum Lindl is a valuable medicinal herb and gardening plant due to its ornamental value and special medical value. Low temperature is a major bottleneck restricting D. catenatum expansion towards the north, which influences the quality and yield of D. catenatum. In this study, we analysed the cold response of D. catenatum by RNA-Seq. A total of 4302 differentially expressed genes were detected under cold stress, which were mainly linked to protein kinase activity, membrane transport and the glycan biosynthesis and metabolism pathway. We also identified 4005 differential alternative events in 2319 genes significantly regulated by cold stress. Exon skipping and intron retention were the most common alternative splicing isoforms. Numerous genes were identified that differentially modulated under cold stress, including cold-induced transcription factors and splicing factors mediated by AS (alternative splicing). GO enrichment analysis found that differentially alternatively spliced genes without differential expression levels were related to RNA/mRNA processing and spliceosomes. DAS (differentially alternative splicing) genes with different expression levels were mainly enriched in protein kinase activity, plasma membrane and cellular response to stimulus. We further identified and cloned DcCBP20 in D. catenatum; we found that DcCBP20 promotes the generation of alternative splicing variants in cold-induced genes under cold stress via genetic experiments and RT–PCR. Taken together, our results identify the main cold-response pathways and alternative splicing events in D. catenatum responding to cold treatment and that DcCBP20 of D. catenatum get involved in regulating the AS and gene expression of cold-induced genes during this process. Our study will contribute to understanding the role of AS genes in regulating the cold stress response in D. catenatum.
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39
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Reixachs-Solé M, Eyras E. Uncovering the impacts of alternative splicing on the proteome with current omics techniques. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1707. [PMID: 34979593 PMCID: PMC9542554 DOI: 10.1002/wrna.1707] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 12/15/2022]
Abstract
The high‐throughput sequencing of cellular RNAs has underscored a broad effect of isoform diversification through alternative splicing on the transcriptome. Moreover, the differential production of transcript isoforms from gene loci has been recognized as a critical mechanism in cell differentiation, organismal development, and disease. Yet, the extent of the impact of alternative splicing on protein production and cellular function remains a matter of debate. Multiple experimental and computational approaches have been developed in recent years to address this question. These studies have unveiled how molecular changes at different steps in the RNA processing pathway can lead to differences in protein production and have functional effects. New and emerging experimental technologies open exciting new opportunities to develop new methods to fully establish the connection between messenger RNA expression and protein production and to further investigate how RNA variation impacts the proteome and cell function. This article is categorized under:RNA Processing > Splicing Regulation/Alternative Splicing Translation > Regulation RNA Evolution and Genomics > Computational Analyses of RNA
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Affiliation(s)
- Marina Reixachs-Solé
- The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia.,EMBL Australia Partner Laboratory Network and the Australian National University, Canberra, Australian Capital Territory, Australia
| | - Eduardo Eyras
- The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia.,EMBL Australia Partner Laboratory Network and the Australian National University, Canberra, Australian Capital Territory, Australia.,Catalan Institution for Research and Advanced Studies, Barcelona, Spain.,Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
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40
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Abstract
Alternative splicing enables higher eukaryotes to expand mRNA diversity from a finite number of genes through highly combinatorial splice site selection mechanisms that are influenced by the sequence of competing splice sites, cis-regulatory elements binding trans-acting factors, the length of exons and introns harbouring alternative splice sites and RNA secondary structures at putative splice junctions. To test the hypothesis that the intron definition or exon definition modes of splice site recognition direct the selection of alternative splice patterns, we created a database of alternative splice site usage (ALTssDB). When alternative splice sites are embedded within short introns (intron definition), the 5' and 3' splice sites closest to each other across the intron preferentially pair, consistent with previous observations. However, when alternative splice sites are embedded within large flanking introns (exon definition), the 5' and 3' splice sites closest to each other across the exon are preferentially selected. Thus, alternative splicing decisions are influenced by the intron and exon definition modes of splice site recognition. The results demonstrate that the spliceosome pairs splice sites that are closest in proximity within the unit of initial splice site selection.
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Affiliation(s)
- Francisco Carranza
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
| | - Hossein Shenasa
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
| | - Klemens J Hertel
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
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41
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Abstract
In Eukarya, immature mRNA transcripts (pre-mRNA) often contain coding sequences, or exons, interleaved by non-coding sequences, or introns. Introns are removed upon splicing, and further regulation of the retained exons leads to alternatively spliced mRNA. The splicing reaction requires the stepwise assembly of the spliceosome, a macromolecular machine composed of small nuclear ribonucleoproteins (snRNPs). This review focuses on the early stage of spliceosome assembly, when U1 snRNP defines each intron 5’-splice site (5ʹss) in the pre-mRNA. We first introduce the splicing reaction and the impact of alternative splicing on gene expression regulation. Thereafter, we extensively discuss splicing descriptors that influence the 5ʹss selection by U1 snRNP, such as sequence determinants, and interactions mediated by U1-specific proteins or U1 small nuclear RNA (U1 snRNA). We also include examples of diseases that affect the 5ʹss selection by U1 snRNP, and discuss recent therapeutic advances that manipulate U1 snRNP 5ʹss selectivity with antisense oligonucleotides and small-molecule splicing switches.
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Affiliation(s)
- Florian Malard
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Cameron D Mackereth
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Sébastien Campagne
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
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42
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Cataldi S, Aprile M, Melillo D, Mucel I, Giorgetti-Peraldi S, Cormont M, Italiani P, Blüher M, Tanti JF, Ciccodicola A, Costa V. TNFα Mediates Inflammation-Induced Effects on PPARG Splicing in Adipose Tissue and Mesenchymal Precursor Cells. Cells 2021; 11:cells11010042. [PMID: 35011604 PMCID: PMC8750445 DOI: 10.3390/cells11010042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 01/18/2023] Open
Abstract
Low-grade chronic inflammation and reduced differentiation capacity are hallmarks of hypertrophic adipose tissue (AT) and key contributors of insulin resistance. We identified PPARGΔ5 as a dominant-negative splicing isoform overexpressed in the AT of obese/diabetic patients able to impair adipocyte differentiation and PPARγ activity in hypertrophic adipocytes. Herein, we investigate the impact of macrophage-secreted pro-inflammatory factors on PPARG splicing, focusing on PPARGΔ5. We report that the epididymal AT of LPS-treated mice displays increased PpargΔ5/cPparg ratio and reduced expression of Pparg-regulated genes. Interestingly, pro-inflammatory factors secreted from murine and human pro-inflammatory macrophages enhance the PPARGΔ5/cPPARG ratio in exposed adipogenic precursors. TNFα is identified herein as factor able to alter PPARG splicing—increasing PPARGΔ5/cPPARG ratio—through PI3K/Akt signaling and SRp40 splicing factor. In line with in vitro data, TNFA expression is higher in the SAT of obese (vs. lean) patients and positively correlates with PPARGΔ5 levels. In conclusion, our results indicate that inflammatory factors secreted by metabolically-activated macrophages are potent stimuli that modulate the expression and splicing of PPARG. The resulting imbalance between canonical and dominant negative isoforms may crucially contribute to impair PPARγ activity in hypertrophic AT, exacerbating the defective adipogenic capacity of precursor cells.
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Affiliation(s)
- Simona Cataldi
- Institute of Genetics and Biophysics ‘‘Adriano Buzzati-Traverso’’, CNR, Via P. Castellino 111, 80131 Naples, Italy; (S.C.); (M.A.); (A.C.)
| | - Marianna Aprile
- Institute of Genetics and Biophysics ‘‘Adriano Buzzati-Traverso’’, CNR, Via P. Castellino 111, 80131 Naples, Italy; (S.C.); (M.A.); (A.C.)
| | - Daniela Melillo
- Institute of Biochemistry and Cell Biology, CNR, Via P. Castellino 111, 80131 Naples, Italy; (D.M.); (P.I.)
| | - Inès Mucel
- Université Côte d’Azur, Inserm UMR1065, C3M, Team Cellular and Molecular Pathophysiology of Obesity, 06204 Nice, France; (I.M.); (S.G.-P.); (M.C.); (J.-F.T.)
| | - Sophie Giorgetti-Peraldi
- Université Côte d’Azur, Inserm UMR1065, C3M, Team Cellular and Molecular Pathophysiology of Obesity, 06204 Nice, France; (I.M.); (S.G.-P.); (M.C.); (J.-F.T.)
| | - Mireille Cormont
- Université Côte d’Azur, Inserm UMR1065, C3M, Team Cellular and Molecular Pathophysiology of Obesity, 06204 Nice, France; (I.M.); (S.G.-P.); (M.C.); (J.-F.T.)
| | - Paola Italiani
- Institute of Biochemistry and Cell Biology, CNR, Via P. Castellino 111, 80131 Naples, Italy; (D.M.); (P.I.)
| | - Matthias Blüher
- Medical Department III-Endocrinology, Nephrology and Rheumatology, University of Leipzig, 04103 Leipzig, Germany;
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Philipp-Rosenthal-Str. 27, 04103 Leipzig, Germany
| | - Jean-François Tanti
- Université Côte d’Azur, Inserm UMR1065, C3M, Team Cellular and Molecular Pathophysiology of Obesity, 06204 Nice, France; (I.M.); (S.G.-P.); (M.C.); (J.-F.T.)
| | - Alfredo Ciccodicola
- Institute of Genetics and Biophysics ‘‘Adriano Buzzati-Traverso’’, CNR, Via P. Castellino 111, 80131 Naples, Italy; (S.C.); (M.A.); (A.C.)
- Department of Science and Technology, University of Naples ‘‘Parthenope’’, 80143 Naples, Italy
| | - Valerio Costa
- Institute of Genetics and Biophysics ‘‘Adriano Buzzati-Traverso’’, CNR, Via P. Castellino 111, 80131 Naples, Italy; (S.C.); (M.A.); (A.C.)
- Correspondence: ; Tel.: +39-0816132617
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Müller L, Moskorz W, Brillen AL, Hillebrand F, Ostermann PN, Kiel N, Walotka L, Ptok J, Timm J, Lübke N, Schaal H. Altered HIV-1 mRNA Splicing Due to Drug-Resistance-Associated Mutations in Exon 2/2b. Int J Mol Sci 2021; 23:ijms23010156. [PMID: 35008581 PMCID: PMC8745674 DOI: 10.3390/ijms23010156] [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: 11/15/2021] [Revised: 12/18/2021] [Accepted: 12/22/2021] [Indexed: 12/02/2022] Open
Abstract
The underlying molecular mechanism and their general effect on the replication capacity of HIV 1 drug-resistance-associated mutations is often poorly understood. To elucidate the effect of two such mutations located in a region with a high density of spicing regulatory elements on the HIV-1-splicing outcome, bioinformatic predictions were combined with transfection and infection experiments. Results show that the previously described R263K drug-resistance-associated integrase mutation has additionally a severe effect on the ESE2b splicing regulatory element (SRE) in exon 2b, which causes loss of SD2b recognition. This was confirmed by an R263R silent mutation with a similar predicted effect on the exon 2b SRE. In contrast, a V260I mutation and its silent counterpart with a lower effect on ESS2b did not exhibit any differences in the splicing pattern. Since HIV-1 highly relies on a balanced splicing reaction, changes in the splicing outcome can contribute to changes in viral replication and might add to the effect of escape mutations toward antiviral drugs. Thus, a classification of mutations purely addressing proteins is insufficient.
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44
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Ling Y, Mahfouz MM, Zhou S. Pre-mRNA alternative splicing as a modulator for heat stress response in plants. TRENDS IN PLANT SCIENCE 2021; 26:1153-1170. [PMID: 34334317 DOI: 10.1016/j.tplants.2021.07.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/01/2021] [Accepted: 07/07/2021] [Indexed: 05/11/2023]
Abstract
The molecular responses of plants to the important abiotic stress, heat stress (HS), have been extensively studied at the transcriptional level. Alternative splicing (AS) is a post-transcriptional regulatory process in which an intron-containing gene can generate more than one mRNA variant. The impact of HS on the pre-mRNA splicing process has been reported in various eukaryotes but seldom discussed in-depth, especially in plants. Here, we review AS regulation in response to HS in different plant species. We discuss potential molecular mechanisms controlling heat-inducible AS regulation in plants and hypothesize that AS regulation participates in heat-priming establishment and HS memory maintenance. We propose that the pre-mRNA splicing variation is an important regulator of plant HS responses (HSRs).
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Affiliation(s)
- Yu Ling
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, PR China; Laboratory for Genome Engineering, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; South China Branch of National Saline-Alkali Tolerant Rice Technology Innovation Center, Zhanjiang, 524088, PR China.
| | - Magdy M Mahfouz
- Laboratory for Genome Engineering, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Shuangxi Zhou
- New Zealand Institute for Plant and Food Research Limited, Hawke's Bay 4130, New Zealand
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45
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Enriched Alternative Splicing in Islets of Diabetes-Susceptible Mice. Int J Mol Sci 2021; 22:ijms22168597. [PMID: 34445304 PMCID: PMC8395343 DOI: 10.3390/ijms22168597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/28/2021] [Accepted: 08/05/2021] [Indexed: 12/30/2022] Open
Abstract
Dysfunctional islets of Langerhans are a hallmark of type 2 diabetes (T2D). We hypothesize that differences in islet gene expression alternative splicing which can contribute to altered protein function also participate in islet dysfunction. RNA sequencing (RNAseq) data from islets of obese diabetes-resistant and diabetes-susceptible mice were analyzed for alternative splicing and its putative genetic and epigenetic modulators. We focused on the expression levels of chromatin modifiers and SNPs in regulatory sequences. We identified alternative splicing events in islets of diabetes-susceptible mice amongst others in genes linked to insulin secretion, endocytosis or ubiquitin-mediated proteolysis pathways. The expression pattern of 54 histones and chromatin modifiers, which may modulate splicing, were markedly downregulated in islets of diabetic animals. Furthermore, diabetes-susceptible mice carry SNPs in RNA-binding protein motifs and in splice sites potentially responsible for alternative splicing events. They also exhibit a larger exon skipping rate, e.g., in the diabetes gene Abcc8, which might affect protein function. Expression of the neuronal splicing factor Srrm4 which mediates inclusion of microexons in mRNA transcripts was markedly lower in islets of diabetes-prone compared to diabetes-resistant mice, correlating with a preferential skipping of SRRM4 target exons. The repression of Srrm4 expression is presumably mediated via a higher expression of miR-326-3p and miR-3547-3p in islets of diabetic mice. Thus, our study suggests that an altered splicing pattern in islets of diabetes-susceptible mice may contribute to an elevated T2D risk.
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Li J, Li G, Qi Y, Lu Y, Wang H, Shi K, Li D, Shi J, Stovall DB, Sui G. SRSF5 regulates alternative splicing of DMTF1 pre-mRNA through modulating SF1 binding. RNA Biol 2021; 18:318-336. [PMID: 34291726 DOI: 10.1080/15476286.2021.1947644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
ABBREVIATIONS ARF: alternative reading frame, that is, p14ARF, or CDKN2A (cyclin-dependent kinase inhibitor 2A); β-gal: β-galactosidase; CLIP-seq: crosslinking and immunoprecipitation-sequencing; DMTF1: the cyclin D binding myb-like transcription factor 1; ESS/ESE: exonic splicing silencer/enhancer; Ex: exon; FBS: fetal bovine serum; Gluc: Gaussia luciferase; hnRNPs: heterogeneous nuclear ribonucleoproteins; In: intron; ISS/ISE: intronic splicing silencer/enhancer; PBS: phosphate-buffered saline; PCR: polymerase chain reaction; PSI: percent-splice-in; qPCR: quantitative real-time PCR; RIP: RNA immunoprecipitation; RNAseq: RNA sequencing; RT: reverse transcription; SF1: splicing factor 1; SR: serine/arginine-rich proteins; SRSF5: serine and arginine-rich splicing factor 5; TCGA: the cancer genome atlas; UCSC: University of California, Santa Cruz. WT: Wild type.
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Affiliation(s)
- Jialiang Li
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Guangyue Li
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Yige Qi
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Yao Lu
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Hao Wang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Ke Shi
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Dangdang Li
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Jinming Shi
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Daniel B Stovall
- College of Arts and Sciences, Winthrop University, Rock Hill, SC, USA
| | - Guangchao Sui
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
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Dikaya V, El Arbi N, Rojas-Murcia N, Nardeli SM, Goretti D, Schmid M. Insights into the role of alternative splicing in plant temperature response. JOURNAL OF EXPERIMENTAL BOTANY 2021:erab234. [PMID: 34105719 DOI: 10.1093/jxb/erab234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Indexed: 05/21/2023]
Abstract
Alternative splicing occurs in all eukaryotic organisms. Since the first description of multiexon genes and the splicing machinery, the field has expanded rapidly, especially in animals and yeast. However, our knowledge about splicing in plants is still quite fragmented. Though eukaryotes show some similarity in the composition and dynamics of the splicing machinery, observations of unique plant traits are only starting to emerge. For instance, plant alternative splicing is closely linked to their ability to perceive various environmental stimuli. Due to their sessile lifestyle, temperature is a central source of information allowing plants to adjust their development to match current growth conditions. Hence, seasonal temperature fluctuations and day-night cycles can strongly influence plant morphology across developmental stages. Here we discuss the available data about temperature-dependent alternative splicing in plants. Given its fragmented state it is not always possible to fit specific observations into a coherent picture, yet it is sufficient to estimate the complexity of this field and the need of further research. Better understanding of alternative splicing as a part of plant temperature response and adaptation may also prove to be a powerful tool for both, fundamental and applied sciences.
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Affiliation(s)
- Varvara Dikaya
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Nabila El Arbi
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Nelson Rojas-Murcia
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Sarah Muniz Nardeli
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Daniela Goretti
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Markus Schmid
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
- Beijing Advanced Innovation Centre for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, People's Republic of China
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48
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Grewe B, Vogt C, Horstkötter T, Tippler B, Xiao H, Müller B, Überla K, Wagner R, Asbach B, Bohne J. The HIV 5' Gag Region Displays a Specific Nucleotide Bias Regulating Viral Splicing and Infectivity. Viruses 2021; 13:v13060997. [PMID: 34071819 PMCID: PMC8227319 DOI: 10.3390/v13060997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/17/2021] [Accepted: 05/22/2021] [Indexed: 11/16/2022] Open
Abstract
Alternative splicing and the expression of intron-containing mRNAs is one hallmark of HIV gene expression. To facilitate the otherwise hampered nuclear export of non-fully processed mRNAs, HIV encodes the Rev protein, which recognizes its intronic response element and fuels the HIV RNAs into the CRM-1-dependent nuclear protein export pathway. Both alternative splicing and Rev-dependency are regulated by the primary HIV RNA sequence. Here, we show that these processes are extremely sensitive to sequence alterations in the 5’coding region of the HIV genomic RNA. Increasing the GC content by insertion of either GFP or silent mutations activates a cryptic splice donor site in gag, entirely deregulates the viral splicing pattern, and lowers infectivity. Interestingly, an adaptation of the inserted GFP sequence toward an HIV-like nucleotide bias reversed these phenotypes completely. Of note, the adaptation yielded completely different primary sequences although encoding the same amino acids. Thus, the phenotypes solely depend on the nucleotide composition of the two GFP versions. This is a strong indication of an HIV-specific mRNP code in the 5′ gag region wherein the primary RNA sequence bias creates motifs for RNA-binding proteins and controls the fate of the HIV-RNA in terms of viral gene expression and infectivity.
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Affiliation(s)
- Bastian Grewe
- Department of Molecular and Medical Virology, Ruhr-University, 44801 Bochum, Germany; (B.G.); (B.T.); (H.X.); (B.M.); (K.Ü.)
| | - Carolin Vogt
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (C.V.); (T.H.)
| | - Theresa Horstkötter
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (C.V.); (T.H.)
| | - Bettina Tippler
- Department of Molecular and Medical Virology, Ruhr-University, 44801 Bochum, Germany; (B.G.); (B.T.); (H.X.); (B.M.); (K.Ü.)
- Department of Biochemistry, Ruhr-University, 44780 Bochum, Germany
| | - Han Xiao
- Department of Molecular and Medical Virology, Ruhr-University, 44801 Bochum, Germany; (B.G.); (B.T.); (H.X.); (B.M.); (K.Ü.)
- Institute of Clinical and Molecular Virology, University Clinics Erlangen, 91054 Erlangen, Germany
| | - Bianca Müller
- Department of Molecular and Medical Virology, Ruhr-University, 44801 Bochum, Germany; (B.G.); (B.T.); (H.X.); (B.M.); (K.Ü.)
| | - Klaus Überla
- Department of Molecular and Medical Virology, Ruhr-University, 44801 Bochum, Germany; (B.G.); (B.T.); (H.X.); (B.M.); (K.Ü.)
- Institute of Clinical and Molecular Virology, University Clinics Erlangen, 91054 Erlangen, Germany
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, University Regensburg, 93053 Regensburg, Germany; (R.W.); (B.A.)
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, 93053 Regensburg, Germany
| | - Benedikt Asbach
- Institute of Medical Microbiology and Hygiene, University Regensburg, 93053 Regensburg, Germany; (R.W.); (B.A.)
| | - Jens Bohne
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (C.V.); (T.H.)
- Correspondence: ; Tel.: +49-511-532-4308
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49
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Ptok J, Müller L, Ostermann PN, Ritchie A, Dilthey AT, Theiss S, Schaal H. Modifying splice site usage with ModCon: Maintaining the genetic code while changing the underlying mRNP code. Comput Struct Biotechnol J 2021; 19:3069-3076. [PMID: 34136105 PMCID: PMC8178101 DOI: 10.1016/j.csbj.2021.05.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 11/22/2022] Open
Abstract
Codon degeneracy of amino acid sequences permits an additional “mRNP code” layer underlying the genetic code that is related to RNA processing. In pre-mRNA splicing, splice site usage is determined by both intrinsic strength and sequence context providing RNA binding sites for splicing regulatory proteins. In this study, we systematically examined modification of splicing regulatory properties in the neighborhood of a GT site, i.e. potential splice site, without altering the encoded amino acids. We quantified the splicing regulatory properties of the neighborhood around a potential splice site by its Splice Site HEXplorer Weight (SSHW) based on the HEXplorer score algorithm. To systematically modify GT site neighborhoods, either minimizing or maximizing their SSHW, we designed the novel stochastic optimization algorithm ModCon that applies a genetic algorithm with stochastic crossover, insertion and random mutation elements supplemented by a heuristic sliding window approach. To assess the achievable range in SSHW in human splice donors without altering the encoded amino acids, we applied ModCon to a set of 1000 randomly selected Ensembl annotated human splice donor sites, achieving substantial and accurate changes in SSHW. Using ModCon optimization, we successfully switched splice donor usage in a splice site competition reporter containing coding sequences from FANCA, FANCB or BRCA2, while retaining their amino acid coding information. The ModCon algorithm and its R package implementation can assist in reporter design by either introducing novel splice sites, silencing accidental, undesired splice sites, and by generally modifying the entire mRNP code while maintaining the genetic code.
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Key Words
- A, adenine
- F1, filial sequence 1
- G, guanine
- GA, genetic algorithm
- HBS, HBond score
- HBond score
- HEXplorer score
- HZEI, HEXplorer score
- P1, parental sequence 1
- SA, splice acceptor
- SD, splice donor
- SR proteins, serine- and arginine-rich proteins
- SRP, splicing regulatory protein
- SSHW, splice site HEXplorer weight
- SW, sliding window
- Splice donor
- Splicing regulatory proteins
- Splicing reporter
- T, thymine
- eGFP, enhanced green fluorescent protein
- hnRNP, heterogeneous nuclear ribonucleoproteins
- nt, nucleotides
- pre-mRNA splicing
- pre-mRNA, precursor messenger RNA
- snRNA, small nuclear RNA
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Affiliation(s)
- Johannes Ptok
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Lisa Müller
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Philipp Niklas Ostermann
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Anastasia Ritchie
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Alexander T Dilthey
- Institute of Medical Statistics and Computational Biology, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stephan Theiss
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
| | - Heiner Schaal
- Institute of Virology, Medical Faculty, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf, Germany
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50
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Du JX, Luo YH, Zhang SJ, Wang B, Chen C, Zhu GQ, Zhu P, Cai CZ, Wan JL, Cai JL, Chen SP, Dai Z, Zhu W. Splicing factor SRSF1 promotes breast cancer progression via oncogenic splice switching of PTPMT1. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2021; 40:171. [PMID: 33992102 PMCID: PMC8122567 DOI: 10.1186/s13046-021-01978-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/09/2021] [Indexed: 02/08/2023]
Abstract
Background Intensive evidence has highlighted the effect of aberrant alternative splicing (AS) events on cancer progression when triggered by dysregulation of the SR protein family. Nonetheless, the underlying mechanism in breast cancer (BRCA) remains elusive. Here we sought to explore the molecular function of SRSF1 and identify the key AS events regulated by SRSF1 in BRCA. Methods We conducted a comprehensive analysis of the expression and clinical correlation of SRSF1 in BRCA based on the TCGA dataset, Metabric database and clinical tissue samples. Functional analysis of SRSF1 in BRCA was conducted in vitro and in vivo. SRSF1-mediated AS events and their binding motifs were identified by RNA-seq, RNA immunoprecipitation-PCR (RIP-PCR) and in vivo crosslinking followed by immunoprecipitation (CLIP), which was further validated by the minigene reporter assay. PTPMT1 exon 3 (E3) AS was identified to partially mediate the oncogenic role of SRSF1 by the P-AKT/C-MYC axis. Finally, the expression and clinical significance of these AS events were validated in clinical samples and using the TCGA database. Results SRSF1 expression was consistently upregulated in BRCA samples, positively associated with tumor grade and the Ki-67 index, and correlated with poor prognosis in a hormone receptor-positive (HR+) cohort, which facilitated proliferation, cell migration and inhibited apoptosis in vitro and in vivo. We identified SRSF1-mediated AS events and discovered the SRSF1 binding motif in the regulation of splice switching of PTPMT1. Furthermore, PTPMT1 splice switching was regulated by SRSF1 by binding directly to its motif in E3 which partially mediated the oncogenic role of SRSF1 by the AKT/C-MYC axis. Additionally, PTPMT1 splice switching was validated in tissue samples of BRCA patients and using the TCGA database. The high-risk group, identified by AS of PTPMT1 and expression of SRSF1, possessed poorer prognosis in the stage I/II TCGA BRCA cohort. Conclusions SRSF1 exerts oncogenic roles in BRCA partially by regulating the AS of PTPMT1, which could be a therapeutic target candidate in BRCA and a prognostic factor in HR+ BRCA patient. Supplementary Information The online version contains supplementary material available at 10.1186/s13046-021-01978-8.
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Affiliation(s)
- Jun-Xian Du
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Yi-Hong Luo
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Si-Jia Zhang
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Biao Wang
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Cong Chen
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Gui-Qi Zhu
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Ping Zhu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, No. 130 Dongan Road, Shanghai, 200032, China
| | - Cheng-Zhe Cai
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Jing-Lei Wan
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Jia-Liang Cai
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Shi-Ping Chen
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China
| | - Zhi Dai
- Liver Cancer Institute, Zhongshan Hospital, Fudan University & State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, 200032, China. .,Key Laboratory of Carcinogenesis and Cancer Invasion, Fudan University, Ministry of Education, Shanghai, 200032, China.
| | - Wei Zhu
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
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