1
|
Lin L, Zhao J, Kubota N, Li Z, Lam YL, Nguyen LP, Yang L, Pokharel SP, Blue SM, Yee BA, Chen R, Yeo GW, Chen CW, Chen L, Zheng S. Epistatic interactions between NMD and TRP53 control progenitor cell maintenance and brain size. Neuron 2024:S0896-6273(24)00244-7. [PMID: 38697111 DOI: 10.1016/j.neuron.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/14/2024] [Accepted: 04/05/2024] [Indexed: 05/04/2024]
Abstract
Mutations in human nonsense-mediated mRNA decay (NMD) factors are enriched in neurodevelopmental disorders. We show that deletion of key NMD factor Upf2 in mouse embryonic neural progenitor cells causes perinatal microcephaly but deletion in immature neurons does not, indicating NMD's critical roles in progenitors. Upf2 knockout (KO) prolongs the cell cycle of radial glia progenitor cells, promotes their transition into intermediate progenitors, and leads to reduced upper-layer neurons. CRISPRi screening identified Trp53 knockdown rescuing Upf2KO progenitors without globally reversing NMD inhibition, implying marginal contributions of most NMD targets to the cell cycle defect. Integrated functional genomics shows that NMD degrades selective TRP53 downstream targets, including Cdkn1a, which, without NMD suppression, slow the cell cycle. Trp53KO restores the progenitor cell pool and rescues the microcephaly of Upf2KO mice. Therefore, one physiological role of NMD in the developing brain is to degrade selective TRP53 targets to control progenitor cell cycle and brain size.
Collapse
Affiliation(s)
- Lin Lin
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA 92521, USA; Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA 92521, USA
| | - Jingrong Zhao
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA 92521, USA; Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA 92521, USA
| | - Naoto Kubota
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA 92521, USA; Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA 92521, USA
| | - Zhelin Li
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA 92521, USA
| | - Yi-Li Lam
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA 92521, USA; Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA 92521, USA
| | - Lauren P Nguyen
- Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Lu Yang
- Department of Systems Biology, Beckman Research Institute, City of Hope, Duarte, CA, USA
| | - Sheela P Pokharel
- Department of Systems Biology, Beckman Research Institute, City of Hope, Duarte, CA, USA
| | - Steven M Blue
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Brian A Yee
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Renee Chen
- Department of Systems Biology, Beckman Research Institute, City of Hope, Duarte, CA, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Chun-Wei Chen
- Department of Systems Biology, Beckman Research Institute, City of Hope, Duarte, CA, USA; City of Hope Comprehensive Cancer Center, Duarte, CA, USA
| | - Liang Chen
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Sika Zheng
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA 92521, USA; Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA 92521, USA; Interdepartmental Neuroscience Program, University of California, Riverside, Riverside, CA 92521, USA.
| |
Collapse
|
2
|
Fanara S, Schloesser M, Joris M, De Franco S, Vandevenne M, Kerff F, Hanikenne M, Motte P. The Arabidopsis SR45 splicing factor bridges the splicing machinery and the exon-exon junction complex. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:2280-2298. [PMID: 38180875 DOI: 10.1093/jxb/erae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 01/04/2024] [Indexed: 01/07/2024]
Abstract
The Arabidopsis splicing factor serine/arginine-rich 45 (SR45) contributes to several biological processes. The sr45-1 loss-of-function mutant exhibits delayed root development, late flowering, unusual numbers of floral organs, shorter siliques with decreased seed sets, narrower leaves and petals, and altered metal distribution. SR45 bears a unique RNA recognition motif (RRM) flanked by one serine/arginine-rich (RS) domain on both sides. Here, we studied the function of each SR45 domains by examining their involvement in: (i) the spatial distribution of SR45; (ii) the establishment of a protein-protein interaction network including spliceosomal and exon-exon junction complex (EJC) components; and (iii) the RNA binding specificity. We report that the endogenous SR45 promoter is active during vegetative and reproductive growth, and that the SR45 protein localizes in the nucleus. We demonstrate that the C-terminal arginine/serine-rich domain is a determinant of nuclear localization. We show that the SR45 RRM domain specifically binds purine-rich RNA motifs via three residues (H101, H141, and Y143), and is also involved in protein-protein interactions. We further show that SR45 bridges both mRNA splicing and surveillance machineries as a partner of EJC core components and peripheral factors, which requires phosphoresidues probably phosphorylated by kinases from both the CLK and SRPK families. Our findings provide insights into the contribution of each SR45 domain to both spliceosome and EJC assemblies.
Collapse
Affiliation(s)
- Steven Fanara
- InBioS-PhytoSystems, Functional Genomics and Plant Molecular Imaging, University of Liège, 4000, Liège, Belgium
| | - Marie Schloesser
- InBioS-PhytoSystems, Functional Genomics and Plant Molecular Imaging, University of Liège, 4000, Liège, Belgium
| | - Marine Joris
- InBioS-PhytoSystems, Functional Genomics and Plant Molecular Imaging, University of Liège, 4000, Liège, Belgium
| | - Simona De Franco
- InBioS-Center for Protein Engineering, Laboratory of Biological Macromolecules, University of Liège, 4000, Liège, Belgium
| | - Marylène Vandevenne
- InBioS-Center for Protein Engineering, Laboratory of Biological Macromolecules, University of Liège, 4000, Liège, Belgium
| | - Frédéric Kerff
- InBioS-Center for Protein Engineering, Laboratory of Crystallography, University of Liège, 4000, Liège, Belgium
| | - Marc Hanikenne
- InBioS-PhytoSystems, Translational Plant Biology, University of Liège, 4000, Liège, Belgium
| | - Patrick Motte
- InBioS-PhytoSystems, Functional Genomics and Plant Molecular Imaging, University of Liège, 4000, Liège, Belgium
| |
Collapse
|
3
|
Da Cunha D, Miro J, Van Goethem C, Notarnicola C, Hugon G, Carnac G, Cossée M, Koenig M, Tuffery-Giraud S. The exon junction complex is required for DMD gene splicing fidelity and myogenic differentiation. Cell Mol Life Sci 2024; 81:150. [PMID: 38512499 PMCID: PMC10957711 DOI: 10.1007/s00018-024-05188-1] [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: 09/10/2023] [Revised: 02/14/2024] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
Deposition of the exon junction complex (EJC) upstream of exon-exon junctions helps maintain transcriptome integrity by preventing spurious re-splicing events in already spliced mRNAs. Here we investigate the importance of EJC for the correct splicing of the 2.2-megabase-long human DMD pre-mRNA, which encodes dystrophin, an essential protein involved in cytoskeletal organization and cell signaling. Using targeted RNA-seq, we show that knock-down of the eIF4A3 and Y14 core components of EJC in a human muscle cell line causes an accumulation of mis-splicing events clustered towards the 3' end of the DMD transcript (Dp427m). This deregulation is conserved in the short Dp71 isoform expressed ubiquitously except in adult skeletal muscle and is rescued with wild-type eIF4A3 and Y14 proteins but not with an EJC assembly-defective mutant eIF4A3. MLN51 protein and EJC-associated ASAP/PSAP complexes independently modulate the inclusion of the regulated exons 71 and 78. Our data confirm the protective role of EJC in maintaining splicing fidelity, which in the DMD gene is necessary to preserve the function of the critical C-terminal protein-protein interaction domain of dystrophin present in all tissue-specific isoforms. Given the role of the EJC in maintaining the integrity of dystrophin, we asked whether the EJC could also be involved in the regulation of a mechanism as complex as skeletal muscle differentiation. We found that eIF4A3 knockdown impairs myogenic differentiation by blocking myotube formation. Collectively, our data provide new insights into the functional roles of EJC in human skeletal muscle.
Collapse
Affiliation(s)
- Dylan Da Cunha
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Julie Miro
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Charles Van Goethem
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Montpellier, France
- Montpellier BioInformatique Pour Le Diagnostic Clinique (MOBIDIC), Plateau de Médecine Moléculaire Et Génomique (PMMG), CHU Montpellier, 34295, Montpellier, France
| | | | - Gérald Hugon
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Gilles Carnac
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
| | - Mireille Cossée
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Montpellier, France
| | - Michel Koenig
- PhyMedExp, Univ Montpellier, CNRS, INSERM, Montpellier, France
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Montpellier, France
| | | |
Collapse
|
4
|
He PC, He C. mRNA accessibility within mRNPs as a determinant of gene expression. Trends Biochem Sci 2024; 49:199-207. [PMID: 38071089 PMCID: PMC10939938 DOI: 10.1016/j.tibs.2023.11.003] [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: 07/31/2023] [Revised: 11/05/2023] [Accepted: 11/10/2023] [Indexed: 01/31/2024]
Abstract
Gene expression is a complex process requiring many control mechanisms to achieve a desired phenotype. DNA accessibility within chromatin is well established as an important determinant of gene expression. By contrast, while mRNA also associates with a complement of proteins, the exact nature of messenger ribonucleoprotein (mRNP) packaging and its functional relevance is not as clear. Recent reports indicate that exon junction complex (EJC)-mediated mRNP packaging renders exon junction-proximal regions inaccessible for m6A methylation, and that EJCs reside within the inaccessible interior of globular transcription and export (TREX) complex-associated nuclear mRNPs. We propose that 'mRNA accessibility' within mRNPs is an important determinant of gene expression that may modulate the specificity of a broad array of regulatory processes including but not limited to m6A methylation.
Collapse
Affiliation(s)
- P Cody He
- Pritzker School of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
5
|
Das R, Panigrahi GK. Messenger RNA Surveillance: Current Understanding, Regulatory Mechanisms, and Future Implications. Mol Biotechnol 2024:10.1007/s12033-024-01062-4. [PMID: 38411790 DOI: 10.1007/s12033-024-01062-4] [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: 10/10/2023] [Accepted: 01/02/2024] [Indexed: 02/28/2024]
Abstract
Nonsense-mediated mRNA decay (NMD) is an evolutionarily conserved surveillance mechanism in eukaryotes primarily deployed to ensure RNA quality control by eliminating aberrant transcripts and also involved in modulating the expression of several physiological transcripts. NMD, the mRNA surveillance pathway, is a major form of gene regulation in eukaryotes. NMD serves as one of the most significant quality control mechanisms as it primarily scans the newly synthesized transcripts and differentiates the aberrant and non-aberrant transcripts. The synthesis of truncated proteins is restricted, which would otherwise lead to cellular dysfunctions. The up-frameshift factors (UPFs) play a central role in executing the NMD event, largely by recognizing and recruiting multiple protein factors that result in the decay of non-physiological mRNAs. NMD exhibits astounding variability in its ability across eukaryotes in an array of pathological and physiological contexts. The detailed understanding of NMD and the underlying molecular mechanisms remains blurred. This review outlines our current understanding of NMD, in regulating multifaceted cellular events during development and disease. It also attempts to identify unanswered questions that deserve further investigation.
Collapse
Affiliation(s)
- Rutupurna Das
- Department of Zoology, School of Applied Sciences, Centurion University of Technology and Management, Jatni, Khordha, Odisha, India
| | - Gagan Kumar Panigrahi
- Department of Zoology, School of Applied Sciences, Centurion University of Technology and Management, Jatni, Khordha, Odisha, India.
| |
Collapse
|
6
|
Luha R, Rana V, Vainstein A, Kumar V. Nonsense-mediated mRNA decay pathway in plants under stress: general gene regulatory mechanism and advances. PLANTA 2024; 259:51. [PMID: 38289504 DOI: 10.1007/s00425-023-04317-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 12/23/2023] [Indexed: 02/01/2024]
Abstract
MAIN CONCLUSION Nonsense-mediated mRNA decay in eukaryotes is vital to cellular homeostasis. Further knowledge of its putative role in plant RNA metabolism under stress is pivotal to developing fitness-optimizing strategies. Nonsense-mediated mRNA decay (NMD), part of the mRNA surveillance pathway, is an evolutionarily conserved form of gene regulation in all living organisms. Degradation of mRNA-bearing premature termination codons and regulation of physiological RNA levels highlight NMD's role in shaping the cellular transcriptome. Initially regarded as purely a tool for cellular RNA quality control, NMD is now considered to mediate various aspects of plant developmental processes and responses to environmental changes. Here we offer a basic understanding of NMD in eukaryotes by explaining the concept of premature termination codon recognition and NMD complex formation. We also provide a detailed overview of the NMD mechanism and its role in gene regulation. The potential role of effectors, including ABCE1, in ribosome recycling during the translation process is also explained. Recent reports of alternatively spliced variants of corresponding genes targeted by NMD in Arabidopsis thaliana are provided in tabular format. Detailed figures are also provided to clarify the NMD concept in plants. In particular, accumulating evidence shows that NMD can serve as a novel alternative strategy for genetic manipulation and can help design RNA-based therapies to combat stress in plants. A key point of emphasis is its function as a gene regulatory mechanism as well as its dynamic regulation by environmental and developmental factors. Overall, a detailed molecular understanding of the NMD mechanism can lead to further diverse applications, such as improving cellular homeostasis in living organisms.
Collapse
Affiliation(s)
- Rashmita Luha
- Department of Botany, School for Basic Sciences, Central University of Punjab, Bathinda, India
- Centre for Biosystems Science and Engineering, Indian Institute of Science Bangalore, Bangaluru, India
| | - Varnika Rana
- Department of Botany, School for Basic Sciences, Central University of Punjab, Bathinda, India
| | - Alexander Vainstein
- Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Vinay Kumar
- Department of Botany, School for Basic Sciences, Central University of Punjab, Bathinda, India.
| |
Collapse
|
7
|
Carrard J, Lejeune F. Nonsense-mediated mRNA decay, a simplified view of a complex mechanism. BMB Rep 2023; 56:625-632. [PMID: 38052423 PMCID: PMC10761751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/31/2023] [Accepted: 11/17/2023] [Indexed: 12/07/2023] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is both a quality control mechanism and a gene regulation pathway. It has been studied for more than 30 years, with an accumulation of many mechanistic details that have often led to debate and hence to different models of NMD activation, particularly in higher eukaryotes. Two models seem to be opposed, since the first requires intervention of the exon junction complex (EJC) to recruit NMD factors downstream of the premature termination codon (PTC), whereas the second involves an EJC-independent mechanism in which NMD factors concentrate in the 3'UTR to initiate NMD in the presence of a PTC. In this review we describe both models, giving recent molecular details and providing experimental arguments supporting one or the other model. In the end it is certainly possible to imagine that these two mechanisms co-exist, rather than viewing them as mutually exclusive. [BMB Reports 2023; 56(12): 625-632].
Collapse
Affiliation(s)
- Julie Carrard
- Univ. Lille, CNRS, Inserm, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, Lille F-59000, France
| | - Fabrice Lejeune
- Univ. Lille, CNRS, Inserm, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, Lille F-59000, France
| |
Collapse
|
8
|
Morillo L, Paternina T, Alasseur Q, Genovesio A, Schwartz S, Le Hir H. Comprehensive mapping of exon junction complex binding sites reveals universal EJC deposition in Drosophila. BMC Biol 2023; 21:246. [PMID: 37936138 PMCID: PMC10630996 DOI: 10.1186/s12915-023-01749-1] [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: 08/04/2023] [Accepted: 10/26/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND The exon junction complex (EJC) is involved in most steps of the mRNA life cycle, ranging from splicing to nonsense-mediated mRNA decay (NMD). It is assembled by the splicing machinery onto mRNA in a sequence-independent manner. A fundamental open question is whether the EJC is deposited onto all exon‒exon junctions or only on a subset of them. Several previous studies have made observations supportive of the latter, yet these have been limited by methodological constraints. RESULTS In this study, we sought to overcome these limitations via the integration of two different approaches for transcriptome-wide mapping of EJCs. Our results revealed that nearly all, if not all, internal exons consistently harbor an EJC in Drosophila, demonstrating that EJC presence is an inherent consequence of the splicing reaction. Furthermore, our study underscores the limitations of eCLIP methods in fully elucidating the landscape of RBP binding sites. Our findings highlight how highly specific (low false positive) methodologies can lead to erroneous interpretations due to partial sensitivity (high false negatives). CONCLUSIONS This study contributes to our understanding of EJC deposition and its association with pre-mRNA splicing. The universal presence of EJC on internal exons underscores its significance in ensuring proper mRNA processing. Additionally, our observations highlight the need to consider both specificity and sensitivity in RBP mapping methodologies.
Collapse
Affiliation(s)
- Lucía Morillo
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Toni Paternina
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Quentin Alasseur
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Auguste Genovesio
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Schraga Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7630031, Israel
| | - Hervé Le Hir
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France.
| |
Collapse
|
9
|
Haddad-Mashadrizeh A, Mirahmadi M, Taghavizadeh Yazdi ME, Gholampour-Faroji N, Bahrami A, Zomorodipour A, Moghadam Matin M, Qayoomian M, Saebnia N. Introns and Their Therapeutic Applications in Biomedical Researches. IRANIAN JOURNAL OF BIOTECHNOLOGY 2023; 21:e3316. [PMID: 38269198 PMCID: PMC10804063 DOI: 10.30498/ijb.2023.334488.3316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 03/23/2023] [Indexed: 01/26/2024]
Abstract
Context Although for a long time, it was thought that intervening sequences (introns) were junk DNA without any function, their critical roles and the underlying molecular mechanisms in genome regulation have only recently come to light. Introns not only carry information for splicing, but they also play many supportive roles in gene regulation at different levels. They are supposed to function as useful tools in various biological processes, particularly in the diagnosis and treatment of diseases. Introns can contribute to numerous biological processes, including gene silencing, gene imprinting, transcription, mRNA metabolism, mRNA nuclear export, mRNA localization, mRNA surveillance, RNA editing, NMD, translation, protein stability, ribosome biogenesis, cell growth, embryonic development, apoptosis, molecular evolution, genome expansion, and proteome diversity through various mechanisms. Evidence Acquisition In order to fulfill the objectives of this study, the following databases were searched: Medline, Scopus, Web of Science, EBSCO, Open Access Journals, and Google Scholar. Only articles published in English were included. Results & Conclusions The intervening sequences of eukaryotic genes have critical functions in genome regulation, as well as in molecular evolution. Here, we summarize recent advances in our understanding of how introns influence genome regulation, as well as their effects on molecular evolution. Moreover, therapeutic strategies based on intron sequences are discussed. According to the obtained results, a thorough understanding of intron functional mechanisms could lead to new opportunities in disease diagnosis and therapies, as well as in biotechnology applications.
Collapse
Affiliation(s)
- Aliakbar Haddad-Mashadrizeh
- Industrial Biotechnology Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mahdi Mirahmadi
- Stem Cell and Regenerative Medicine Research Group, Iranian Academic Center for Education, Culture and Research (ACECR), Khorasan Razavi Branch, Mashhad, Iran
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Nazanin Gholampour-Faroji
- Industrial Biotechnology Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Ahmadreza Bahrami
- Industrial Biotechnology Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | | | - Maryam Moghadam Matin
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohsen Qayoomian
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Neda Saebnia
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| |
Collapse
|
10
|
Rademacher DJ, Bello AI, May JP. CASC3 Biomolecular Condensates Restrict Turnip Crinkle Virus by Limiting Host Factor Availability. J Mol Biol 2023; 435:167956. [PMID: 36642157 PMCID: PMC10338645 DOI: 10.1016/j.jmb.2023.167956] [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: 09/07/2022] [Revised: 12/15/2022] [Accepted: 01/07/2023] [Indexed: 01/15/2023]
Abstract
The exon-junction complex (EJC) plays a role in post-transcriptional gene regulation and exerts antiviral activity towards several positive-strand RNA viruses. However, the spectrum of RNA viruses that are targeted by the EJC or the underlying mechanisms are not well understood. EJC components from Arabidopsis thaliana were screened for antiviral activity towards Turnip crinkle virus (TCV, Tombusviridae). Overexpression of the accessory EJC component CASC3 inhibited TCV accumulation > 10-fold in Nicotiana benthamiana while knock-down of endogenous CASC3 resulted in a > 4-fold increase in TCV accumulation. CASC3 forms cytoplasmic condensates and deletion of the conserved SELOR domain reduced condensate size 7-fold and significantly decreased antiviral activity towards TCV. Mass spectrometry of CASC3 complexes did not identify endogenous stress granule or P-body markers and CASC3 failed to co-localize with an aggresome-specific dye suggesting that CASC3 condensates are distinct from well-established membraneless compartments. Mass spectrometry and bimolecular fluorescence complementation assays revealed that CASC3 sequesters Heat shock protein 70 (Hsp70-1) and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), two host factors with roles in tombusvirus replication. Overexpression of Hsp70-1 or GAPDH reduced the antiviral activity of CASC3 2.1-fold and 2.8-fold, respectively, and suggests that CASC3 inhibits TCV by limiting host factor availability. Unrelated Tobacco mosaic virus (TMV) also depends on Hsp70-1 and CASC3 overexpression restricted TMV accumulation 4-fold and demonstrates that CASC3 antiviral activity is not TCV-specific. Like CASC3, Auxin response factor 19 (ARF19) forms poorly dynamic condensates but ARF19 overexpression failed to inhibit TCV accumulation and suggests that CASC3 has antiviral activities that are not ubiquitous among cytoplasmic condensates.
Collapse
Affiliation(s)
- Dana J Rademacher
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, MO 64110, USA
| | - Abudu I Bello
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, MO 64110, USA
| | - Jared P May
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, MO 64110, USA.
| |
Collapse
|
11
|
Sun L, Mailliot J, Schaffitzel C. Nonsense-Mediated mRNA Decay Factor Functions in Human Health and Disease. Biomedicines 2023; 11:722. [PMID: 36979701 PMCID: PMC10045457 DOI: 10.3390/biomedicines11030722] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a cellular surveillance mechanism that degrades mRNAs with a premature stop codon, avoiding the synthesis of C-terminally truncated proteins. In addition to faulty mRNAs, NMD recognises ~10% of endogenous transcripts in human cells and downregulates their expression. The up-frameshift proteins are core NMD factors and are conserved from yeast to human in structure and function. In mammals, NMD diversified into different pathways that target different mRNAs employing additional NMD factors. Here, we review our current understanding of molecular mechanisms and cellular roles of NMD pathways and the involvement of more specialised NMD factors. We describe the consequences of mutations in NMD factors leading to neurodevelopmental diseases, and the role of NMD in cancer. We highlight strategies of RNA viruses to evade recognition and decay by the NMD machinery.
Collapse
Affiliation(s)
- Lingling Sun
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Justine Mailliot
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Christiane Schaffitzel
- School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK
- Bristol Engineering Biology Centre BrisEngBio, 24 Tyndall Ave, Bristol BS8 1TQ, UK
| |
Collapse
|
12
|
He PC, Wei J, Dou X, Harada BT, Zhang Z, Ge R, Liu C, Zhang LS, Yu X, Wang S, Lyu R, Zou Z, Chen M, He C. Exon architecture controls mRNA m 6A suppression and gene expression. Science 2023; 379:677-682. [PMID: 36705538 PMCID: PMC9990141 DOI: 10.1126/science.abj9090] [Citation(s) in RCA: 60] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 01/16/2023] [Indexed: 01/28/2023]
Abstract
N6-methyladenosine (m6A) is the most abundant messenger RNA (mRNA) modification and plays crucial roles in diverse physiological processes. Using a massively parallel assay for m6A (MPm6A), we discover that m6A specificity is globally regulated by suppressors that prevent m6A deposition in unmethylated transcriptome regions. We identify exon junction complexes (EJCs) as m6A suppressors that protect exon junction-proximal RNA within coding sequences from methylation and regulate mRNA stability through m6A suppression. EJC suppression of m6A underlies multiple global characteristics of mRNA m6A specificity, with the local range of EJC protection sufficient to suppress m6A deposition in average-length internal exons but not in long internal and terminal exons. EJC-suppressed methylation sites colocalize with EJC-suppressed splice sites, which suggests that exon architecture broadly determines local mRNA accessibility to regulatory complexes.
Collapse
Affiliation(s)
- P. Cody He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Jiangbo Wei
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaoyang Dou
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Bryan T. Harada
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Zijie Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
- State Key Laboratory for Conservation and Utilization of Bio-Resources, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, China
| | - Ruiqi Ge
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Chang Liu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Li-Sheng Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xianbin Yu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Shuai Wang
- Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA
| | - Ruitu Lyu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Zhongyu Zou
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Mengjie Chen
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
- Section of Genetic Medicine, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
13
|
Embree CM, Abu-Alhasan R, Singh G. Features and factors that dictate if terminating ribosomes cause or counteract nonsense-mediated mRNA decay. J Biol Chem 2022; 298:102592. [PMID: 36244451 PMCID: PMC9661723 DOI: 10.1016/j.jbc.2022.102592] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a quality control pathway in eukaryotes that continuously monitors mRNA transcripts to ensure truncated polypeptides are not produced. The expression of many normal mRNAs that encode full-length polypeptides is also regulated by this pathway. Such transcript surveillance by NMD is intimately linked to translation termination. When a ribosome terminates translation at a normal termination codon, NMD is not activated, and mRNA can undergo repeated rounds of translation. On the other hand, when translation termination is deemed abnormal, such as that on a premature termination codon, it leads to a series of poorly understood events involving the NMD pathway, which destabilizes the transcript. In this review, we summarize our current understanding of how the NMD machinery interfaces with the translation termination factors to initiate NMD. We also discuss a variety of cis-acting sequence contexts and trans-acting factors that can cause readthrough, ribosome reinitiation, or ribosome frameshifting at stop codons predicted to induce NMD. These alternative outcomes can lead to the ribosome translating downstream of such stop codons and hence the transcript escaping NMD. NMD escape via these mechanisms can have wide-ranging implications on human health, from being exploited by viruses to hijack host cell systems to being harnessed as potential therapeutic possibilities to treat genetic diseases.
Collapse
Affiliation(s)
- Caleb M Embree
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio USA
| | - Rabab Abu-Alhasan
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio USA
| | - Guramrit Singh
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio USA.
| |
Collapse
|
14
|
Nagel M, Noss M, Xu J, Horn N, Ueffing M, Boldt K, Schuele R. The kinesin motor KIF1C is a putative transporter of the exon junction complex in neuronal cells. RNA (NEW YORK, N.Y.) 2022; 29:rna.079426.122. [PMID: 36316088 PMCID: PMC9808568 DOI: 10.1261/rna.079426.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Neurons critically depend on regulated RNA localization and tight control of spatio-temporal gene expression to maintain their morphological and functional integrity. Mutations in the kinesin motor protein gene KIF1C cause Hereditary Spastic Paraplegia, an autosomal recessive disease leading to predominant degeneration of the long axons of central motoneurons. In this study we aimed to gain insight into the molecular function of KIF1C and understand how KIF1C dysfunction contributes to motoneuron degeneration. We used affinity proteomics in neuronally differentiated neuroblastoma cells (SH-SY5Y) to identify the protein complex associated with KIF1C in neuronal cells; candidate interactions were then validated by immunoprecipitation and mislocalization of putative KIF1C cargoes was studied by immunostainings. We found KIF1C to interact with all core components of the exon junction complex (EJC); expression of mutant KIF1C in neuronal cells leads to loss of the typical localization distally in neurites. Instead, EJC core components accumulate in the pericentrosomal region, here co-localizing with mutant KIF1C. These findings suggest KIF1C as a neuronal transporter of the EJC. Interestingly, the binding of KIF1C to the EJC is RNA-mediated, as treatment with RNAse prior to immunoprecipitation almost completely abolishes the interaction. Silica-based solid-phase extraction of UV-crosslinked RNA-protein complexes furthermore supports direct interaction of KIF1C with RNA, as recently also demonstrated for kinesin heavy chain. Taken together, our findings are consistent with a model where KIF1C transports mRNA in an EJC-bound and therefore transcriptionally silenced state along neurites, thus providing the missing link between the EJC and mRNA localization in neurons.
Collapse
Affiliation(s)
- Maike Nagel
- German Center for Neurodegenerative Diseases, Tuebingen; Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen; Graduate School of Cellular and Molecular Neuroscience
| | - Marvin Noss
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen
| | - Jishu Xu
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen; Institute of Medical Genetics and Applied Genomics, University of Tuebingen; Graduate School
| | - Nicola Horn
- Institute for Ophthalmic Research, University of Tuebingen
| | - Marius Ueffing
- Institute of Ophthalmic Research, University of Tuebingen
| | - Karsten Boldt
- Institute of Ophthalmic Research, University of Tuebingen
| | - Rebecca Schuele
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tuebingen; German Center for Neurodegenerative Diseases, Tuebingen
| |
Collapse
|
15
|
Cho H, Abshire ET, Popp MW, Pröschel C, Schwartz JL, Yeo GW, Maquat LE. AKT constitutes a signal-promoted alternative exon-junction complex that regulates nonsense-mediated mRNA decay. Mol Cell 2022; 82:2779-2796.e10. [PMID: 35675814 PMCID: PMC9357146 DOI: 10.1016/j.molcel.2022.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/21/2022] [Accepted: 05/10/2022] [Indexed: 11/28/2022]
Abstract
Despite a long appreciation for the role of nonsense-mediated mRNA decay (NMD) in destroying faulty, disease-causing mRNAs and maintaining normal, physiologic mRNA abundance, additional effectors that regulate NMD activity in mammalian cells continue to be identified. Here, we describe a haploid-cell genetic screen for NMD effectors that has unexpectedly identified 13 proteins constituting the AKT signaling pathway. We show that AKT supersedes UPF2 in exon-junction complexes (EJCs) that are devoid of RNPS1 but contain CASC3, defining an unanticipated insulin-stimulated EJC. Without altering UPF1 RNA binding or ATPase activity, AKT-mediated phosphorylation of the UPF1 CH domain at T151 augments UPF1 helicase activity, which is critical for NMD and also decreases the dependence of helicase activity on ATP. We demonstrate that upregulation of AKT signaling contributes to the hyperactivation of NMD that typifies Fragile X syndrome, as exemplified using FMR1-KO neural stem cells derived from induced pluripotent stem cells.
Collapse
Affiliation(s)
- Hana Cho
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Elizabeth T Abshire
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Maximilian W Popp
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Christoph Pröschel
- Department of Biomedical Genetics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Stem Cell and Regenerative Medicine Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - Joshua L Schwartz
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Stem Cell Program, University of California, San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Stem Cell Program, University of California, San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.
| |
Collapse
|
16
|
Tan K, Stupack DG, Wilkinson MF. Nonsense-mediated RNA decay: an emerging modulator of malignancy. Nat Rev Cancer 2022; 22:437-451. [PMID: 35624152 PMCID: PMC11009036 DOI: 10.1038/s41568-022-00481-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/19/2022] [Indexed: 12/11/2022]
Abstract
Nonsense-mediated RNA decay (NMD) is a highly conserved RNA turnover pathway that selectively degrades RNAs harbouring truncating mutations that prematurely terminate translation, including nonsense, frameshift and some splice-site mutations. Recent studies show that NMD shapes the mutational landscape of tumours by selecting for mutations that tend to downregulate the expression of tumour suppressor genes but not oncogenes. This suggests that NMD can benefit tumours, a notion further supported by the finding that mRNAs encoding immunogenic neoantigen peptides are typically targeted for decay by NMD. Together, this raises the possibility that NMD-inhibitory therapy could be of therapeutic benefit against many tumour types, including those with a high load of neoantigen-generating mutations. Complicating this scenario is the evidence that NMD can also be detrimental for many tumour types, and consequently tumours often have perturbed NMD. NMD may suppress tumour generation and progression by degrading subsets of specific normal mRNAs, including those encoding stress-response proteins, signalling factors and other proteins beneficial for tumours, as well as pro-tumour non-coding RNAs. Together, these findings suggest that NMD-modulatory therapy has the potential to provide widespread therapeutic benefit against diverse tumour types. However, whether NMD should be stimulated or repressed requires careful analysis of the tumour to be treated.
Collapse
Affiliation(s)
- Kun Tan
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Dwayne G Stupack
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, CA, USA.
- UCSD Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA.
| | - Miles F Wilkinson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, La Jolla, CA, USA.
- Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA, USA.
| |
Collapse
|
17
|
Schlautmann LP, Lackmann JW, Altmüller J, Dieterich C, Boehm V, Gehring NH. Exon junction complex-associated multi-adapter RNPS1 nucleates splicing regulatory complexes to maintain transcriptome surveillance. Nucleic Acids Res 2022; 50:5899-5918. [PMID: 35640609 PMCID: PMC9178013 DOI: 10.1093/nar/gkac428] [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: 08/20/2021] [Revised: 05/05/2022] [Accepted: 05/10/2022] [Indexed: 12/04/2022] Open
Abstract
The exon junction complex (EJC) is an RNA-binding multi-protein complex with critical functions in post-transcriptional gene regulation. It is deposited on the mRNA during splicing and regulates diverse processes including pre-mRNA splicing and nonsense-mediated mRNA decay (NMD) via various interacting proteins. The peripheral EJC-binding protein RNPS1 was reported to serve two insufficiently characterized functions: suppressing mis-splicing of cryptic splice sites and activating NMD in the cytoplasm. The analysis of transcriptome-wide effects of EJC and RNPS1 knockdowns in different human cell lines supports the conclusion that RNPS1 can moderately influence NMD activity, but is not a globally essential NMD factor. However, numerous aberrant splicing events strongly suggest that the main function of RNPS1 is splicing regulation. Rescue analyses revealed that the RRM and C-terminal domain of RNPS1 both contribute partially to regulate RNPS1-dependent splicing events. We defined the RNPS1 core interactome using complementary immunoprecipitations and proximity labeling, which identified interactions with splicing-regulatory factors that are dependent on the C-terminus or the RRM domain of RNPS1. Thus, RNPS1 emerges as a multifunctional splicing regulator that promotes correct and efficient splicing of different vulnerable splicing events via the formation of diverse splicing-promoting complexes.
Collapse
Affiliation(s)
- Lena P Schlautmann
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Jan-Wilm Lackmann
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Volker Boehm
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| |
Collapse
|
18
|
Kim YJ, Nomakuchi T, Papaleonidopoulou F, Yang L, Zhang Q, Krainer AR. Gene-specific nonsense-mediated mRNA decay targeting for cystic fibrosis therapy. Nat Commun 2022; 13:2978. [PMID: 35624092 PMCID: PMC9142507 DOI: 10.1038/s41467-022-30668-y] [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: 07/20/2021] [Accepted: 05/06/2022] [Indexed: 12/20/2022] Open
Abstract
Low CFTR mRNA expression due to nonsense-mediated mRNA decay (NMD) is a major hurdle in developing a therapy for cystic fibrosis (CF) caused by the W1282X mutation in the CFTR gene. CFTR-W1282X truncated protein retains partial function, so increasing its levels by inhibiting NMD of its mRNA will likely be beneficial. Because NMD regulates the normal expression of many genes, gene-specific stabilization of CFTR-W1282X mRNA expression is more desirable than general NMD inhibition. Synthetic antisense oligonucleotides (ASOs) designed to prevent binding of exon junction complexes (EJC) downstream of premature termination codons (PTCs) attenuate NMD in a gene-specific manner. We describe cocktails of three ASOs that specifically increase the expression of CFTR-W1282X mRNA and CFTR protein upon delivery into human bronchial epithelial cells. This treatment increases the CFTR-mediated chloride current. These results set the stage for clinical development of an allele-specific therapy for CF caused by the W1282X mutation. The W1282X nonsense mutation in the CFTR gene causes cystic fibrosis by reducing its mRNA and functional protein levels. Here the authors developed antisense-oligonucleotide cocktails that restore CFTR protein function by gene-specific stabilization of CFTR mRNA.
Collapse
Affiliation(s)
- Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Tomoki Nomakuchi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA.,Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Foteini Papaleonidopoulou
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Francis Crick Institute, London, 1140062, UK
| | - Lucia Yang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Qian Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
| |
Collapse
|
19
|
No-nonsense: insights into the functional interplay of nonsense-mediated mRNA decay factors. Biochem J 2022; 479:973-993. [PMID: 35551602 PMCID: PMC9162471 DOI: 10.1042/bcj20210556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/10/2022] [Accepted: 04/12/2022] [Indexed: 11/22/2022]
Abstract
Nonsense-mediated messenger RNA decay (NMD) represents one of the main surveillance pathways used by eukaryotic cells to control the quality and abundance of mRNAs and to degrade viral RNA. NMD recognises mRNAs with a premature termination codon (PTC) and targets them to decay. Markers for a mRNA with a PTC, and thus NMD, are a long a 3′-untranslated region and the presence of an exon-junction complex (EJC) downstream of the stop codon. Here, we review our structural understanding of mammalian NMD factors and their functional interplay leading to a branched network of different interconnected but specialised mRNA decay pathways. We discuss recent insights into the potential impact of EJC composition on NMD pathway choice. We highlight the coexistence and function of different isoforms of up-frameshift protein 1 (UPF1) with an emphasis of their role at the endoplasmic reticulum and during stress, and the role of the paralogs UPF3B and UPF3A, underscoring that gene regulation by mammalian NMD is tightly controlled and context-dependent being conditional on developmental stage, tissue and cell types.
Collapse
|
20
|
Wallmeroth D, Lackmann JW, Kueckelmann S, Altmüller J, Dieterich C, Boehm V, Gehring NH. Human UPF3A and UPF3B enable fault-tolerant activation of nonsense-mediated mRNA decay. EMBO J 2022; 41:e109191. [PMID: 35451084 PMCID: PMC9108619 DOI: 10.15252/embj.2021109191] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 12/14/2022] Open
Abstract
The paralogous human proteins UPF3A and UPF3B are involved in recognizing mRNAs targeted by nonsense‐mediated mRNA decay (NMD). UPF3B has been demonstrated to support NMD, presumably by bridging an exon junction complex (EJC) to the NMD factor UPF2. The role of UPF3A has been described either as a weak NMD activator or an NMD inhibitor. Here, we present a comprehensive functional analysis of UPF3A and UPF3B in human cells using combinatory experimental approaches. Overexpression or knockout of UPF3A as well as knockout of UPF3B did not substantially change global NMD activity. In contrast, the co‐depletion of UPF3A and UPF3B resulted in a marked NMD inhibition and a transcriptome‐wide upregulation of NMD substrates, demonstrating a functional redundancy between both NMD factors. In rescue experiments, UPF2 or EJC binding‐deficient UPF3B largely retained NMD activity. However, combinations of different mutants, including deletion of the middle domain, showed additive or synergistic effects and therefore failed to maintain NMD. Collectively, UPF3A and UPF3B emerge as fault‐tolerant, functionally redundant NMD activators in human cells.
Collapse
Affiliation(s)
- Damaris Wallmeroth
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | | | - Sabrina Kueckelmann
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, Heidelberg University Hospital, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Volker Boehm
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| |
Collapse
|
21
|
Yi Z, Arvola RM, Myers S, Dilsavor CN, Abu Alhasan R, Carter BN, Patton RD, Bundschuh R, Singh G. Mammalian UPF3A and UPF3B can activate nonsense-mediated mRNA decay independently of their exon junction complex binding. EMBO J 2022; 41:e109202. [PMID: 35451102 PMCID: PMC9108626 DOI: 10.15252/embj.2021109202] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 03/21/2022] [Accepted: 03/31/2022] [Indexed: 12/30/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is governed by the three conserved factors-UPF1, UPF2, and UPF3. While all three are required for NMD in yeast, UPF3B is dispensable for NMD in mammals, and its paralog UPF3A is suggested to only weakly activate or even repress NMD due to its weaker binding to the exon junction complex (EJC). Here, we characterize the UPF3A/B-dependence of NMD in human cell lines deleted of one or both UPF3 paralogs. We show that in human colorectal cancer HCT116 cells, NMD can operate in a UPF3B-dependent and -independent manner. While UPF3A is almost dispensable for NMD in wild-type cells, it strongly activates NMD in cells lacking UPF3B. Notably, NMD remains partially active in cells lacking both UPF3 paralogs. Complementation studies in these cells show that EJC-binding domain of UPF3 paralogs is dispensable for NMD. Instead, the conserved "mid" domain of UPF3 paralogs is consequential for their NMD activity. Altogether, our results demonstrate that the mammalian UPF3 proteins play a more active role in NMD than simply bridging the EJC and the UPF complex.
Collapse
Affiliation(s)
- Zhongxia Yi
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - René M Arvola
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Sean Myers
- Department of Physics, The Ohio State University, Columbus, OH, USA
| | - Corinne N Dilsavor
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Rabab Abu Alhasan
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Bayley N Carter
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Robert D Patton
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Physics, The Ohio State University, Columbus, OH, USA
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Physics, The Ohio State University, Columbus, OH, USA.,Department of Chemistry and Biochemistry, The Ohio State University , Columbus, OH, USA.,Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA
| | - Guramrit Singh
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| |
Collapse
|
22
|
The Physiological Roles of the Exon Junction Complex in Development and Diseases. Cells 2022; 11:cells11071192. [PMID: 35406756 PMCID: PMC8997533 DOI: 10.3390/cells11071192] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/19/2022] [Accepted: 03/24/2022] [Indexed: 01/12/2023] Open
Abstract
The exon junction complex (EJC) becomes an increasingly important regulator of early gene expression in the central nervous system (CNS) and other tissues. The EJC is comprised of three core proteins: RNA-binding motif 8A (RBM8A), Mago homolog (MAGOH), eukaryotic initiation factor 4A3 (EIF4A3), and a peripheral EJC factor, metastatic lymph node 51 (MLN51), together with various auxiliary factors. The EJC is assembled specifically at exon-exon junctions on mRNAs, hence the name of the complex. The EJC regulates multiple levels of gene expression, from splicing to translation and mRNA degradation. The functional roles of the EJC have been established as crucial to the normal progress of embryonic and neurological development, with wide ranging implications on molecular, cellular, and organism level function. Dysfunction of the EJC has been implicated in multiple developmental and neurological diseases. In this review, we discuss recent progress on the EJC’s physiological roles.
Collapse
|
23
|
Marques AR, Santos JX, Martiniano H, Vilela J, Rasga C, Romão L, Vicente AM. Gene Variants Involved in Nonsense-Mediated mRNA Decay Suggest a Role in Autism Spectrum Disorder. Biomedicines 2022; 10:biomedicines10030665. [PMID: 35327467 PMCID: PMC8945030 DOI: 10.3390/biomedicines10030665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 02/07/2023] Open
Abstract
Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental condition with unclear etiology. Many genes have been associated with ASD risk, but the underlying mechanisms are still poorly understood. An important post-transcriptional regulatory mechanism that plays an essential role during neurodevelopment, the Nonsense-Mediated mRNA Decay (NMD) pathway, may contribute to ASD risk. In this study, we gathered a list of 46 NMD factors and regulators and investigated the role of genetic variants in these genes in ASD. By conducting a comprehensive search for Single Nucleotide Variants (SNVs) in NMD genes using Whole Exome Sequencing data from 1828 ASD patients, we identified 270 SNVs predicted to be damaging in 28.7% of the population. We also analyzed Copy Number Variants (CNVs) from two cohorts of ASD patients (N = 3570) and discovered 38 CNVs in 1% of cases. Importantly, we discovered 136 genetic variants (125 SNVs and 11 CNVs) in 258 ASD patients that were located within protein domains required for NMD. These gene variants are classified as damaging using in silico prediction tools, and therefore may interfere with proper NMD function in ASD. The discovery of NMD genes as candidates for ASD in large patient genomic datasets provides evidence supporting the involvement of the NMD pathway in ASD pathophysiology.
Collapse
Affiliation(s)
- Ana Rita Marques
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - João Xavier Santos
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Hugo Martiniano
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Joana Vilela
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Célia Rasga
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Luísa Romão
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal
| | - Astrid Moura Vicente
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
- Correspondence:
| |
Collapse
|
24
|
Ho CH, Paolantoni C, Bawankar P, Tang Z, Brown S, Roignant J, Treisman JE. An exon junction complex-independent function of Barentsz in neuromuscular synapse growth. EMBO Rep 2022; 23:e53231. [PMID: 34726300 PMCID: PMC8728599 DOI: 10.15252/embr.202153231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 01/07/2023] Open
Abstract
The exon junction complex controls the translation, degradation, and localization of spliced mRNAs, and three of its core subunits also play a role in splicing. Here, we show that a fourth subunit, Barentsz, has distinct functions within and separate from the exon junction complex in Drosophila neuromuscular development. The distribution of mitochondria in larval muscles requires Barentsz as well as other exon junction complex subunits and is not rescued by a Barentsz transgene in which residues required for binding to the core subunit eIF4AIII are mutated. In contrast, interactions with the exon junction complex are not required for Barentsz to promote the growth of neuromuscular synapses. We find that the Activin ligand Dawdle shows reduced expression in barentsz mutants and acts downstream of Barentsz to control synapse growth. Both barentsz and dawdle are required in motor neurons, muscles, and glia for normal synapse growth, and exogenous Dawdle can rescue synapse growth in the absence of barentsz. These results identify a biological function for Barentsz that is independent of the exon junction complex.
Collapse
Affiliation(s)
- Cheuk Hei Ho
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
| | - Chiara Paolantoni
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
| | - Praveen Bawankar
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Zuojian Tang
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
Computational Biology at Ridgefield US, Global Computational Biology and Digital ScienceBoehringer IngelheimRidgefieldCTUSA
| | - Stuart Brown
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
ExxonMobil Corporate Strategic ResearchAnnandaleNJUSA
| | - Jean‐Yves Roignant
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Jessica E Treisman
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
| |
Collapse
|
25
|
Mesa-Perez M, Hamilton PT, Miranda A, Brodie N, O’Sullivan C, Christie J, Ryan B, Chow R, Goodlett D, Nelson C, Howard P. OUP accepted manuscript. Nucleic Acids Res 2022; 50:1620-1638. [PMID: 35104878 PMCID: PMC8860587 DOI: 10.1093/nar/gkac033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/29/2021] [Accepted: 01/13/2022] [Indexed: 12/03/2022] Open
Abstract
The life of RNA polymerase II (RNAPII) transcripts is shaped by the dynamic formation of mutually exclusive ribonucleoprotein complexes (RNPs) that direct transcript biogenesis and turnover. A key regulator of RNA metabolism in the nucleus is the scaffold protein ARS2 (arsenic resistance protein 2), bound to the cap binding complex (CBC). We report here that alternative splicing of ARS2′s intron 5, generates cytoplasmic isoforms that lack 270 amino acids from the N-terminal of the protein and are functionally distinct from nuclear ARS2. Switching of ARS2 isoforms within the CBC in the cytoplasm has dramatic functional consequences, changing ARS2 from a NMD inhibitor to a NMD promoter that enhances the binding of UPF1 to NCBP1 and ERF1, favouring SURF complex formation, SMG7 recruitment and transcript degradation. ARS2 isoform exchange is also relevant during arsenic stress, where cytoplasmic ARS2 promotes a global response to arsenic in a CBC-independent manner. We propose that ARS2 isoform switching promotes the proper recruitment of RNP complexes during NMD and the cellular response to arsenic stress. The existence of non-redundant ARS2 isoforms is relevant for cell homeostasis, and stress response.
Collapse
Affiliation(s)
- Monica Mesa-Perez
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | | | - Alex Miranda
- Deeley Research Centre, BC Cancer, Victoria, BC V8R 6V5, Canada
| | - Nicholas Brodie
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
- University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, BC V8Z 7X8, Canada
| | - Connor O’Sullivan
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jennifer Christie
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Bridget C Ryan
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - David Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
- University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, BC V8Z 7X8, Canada
| | - Christopher J Nelson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Perry L Howard
- To whom correspondence should be addressed. Tel: +1 260 721 7068; Fax: +1 260 721 8855;
| |
Collapse
|
26
|
Mabin JW, Lewis PW, Brow DA, Dvinge H. Human spliceosomal snRNA sequence variants generate variant spliceosomes. RNA (NEW YORK, N.Y.) 2021; 27:1186-1203. [PMID: 34234030 PMCID: PMC8457000 DOI: 10.1261/rna.078768.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 06/29/2021] [Indexed: 06/02/2023]
Abstract
Human pre-mRNA splicing is primarily catalyzed by the major spliceosome, comprising five small nuclear ribonucleoprotein complexes, U1, U2, U4, U5, and U6 snRNPs, each of which contains the corresponding U-rich snRNA. These snRNAs are encoded by large gene families exhibiting significant sequence variation, but it remains unknown if most human snRNA genes are untranscribed pseudogenes or produce variant snRNAs with the potential to differentially influence splicing. Since gene duplication and variation are powerful mechanisms of evolutionary adaptation, we sought to address this knowledge gap by systematically profiling human U1, U2, U4, and U5 snRNA variant gene transcripts. We identified 55 transcripts that are detectably expressed in human cells, 38 of which incorporate into snRNPs and spliceosomes in 293T cells. All U1 snRNA variants are more than 1000-fold less abundant in spliceosomes than the canonical U1, whereas at least 1% of spliceosomes contain a variant of U2 or U4. In contrast, eight U5 snRNA sequence variants occupy spliceosomes at levels of 1% to 46%. Furthermore, snRNA variants display distinct expression patterns across five human cell lines and adult and fetal tissues. Different RNA degradation rates contribute to the diverse steady state levels of snRNA variants. Our findings suggest that variant spliceosomes containing noncanonical snRNAs may contribute to different tissue- and cell-type-specific alternative splicing patterns.
Collapse
Affiliation(s)
- Justin W Mabin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | - Peter W Lewis
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | - David A Brow
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | - Heidi Dvinge
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| |
Collapse
|
27
|
Faoro C, Ataide SF. Noncanonical Functions and Cellular Dynamics of the Mammalian Signal Recognition Particle Components. Front Mol Biosci 2021; 8:679584. [PMID: 34113652 PMCID: PMC8185352 DOI: 10.3389/fmolb.2021.679584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 04/29/2021] [Indexed: 12/24/2022] Open
Abstract
The signal recognition particle (SRP) is a ribonucleoprotein complex fundamental for co-translational delivery of proteins to their proper membrane localization and secretory pathways. Literature of the past two decades has suggested new roles for individual SRP components, 7SL RNA and proteins SRP9, SRP14, SRP19, SRP54, SRP68 and SRP72, outside the SRP cycle. These noncanonical functions interconnect SRP with a multitude of cellular and molecular pathways, including virus-host interactions, stress response, transcriptional regulation and modulation of apoptosis in autoimmune diseases. Uncovered novel properties of the SRP components present a new perspective for the mammalian SRP as a biological modulator of multiple cellular processes. As a consequence of these findings, SRP components have been correlated with a growing list of diseases, such as cancer progression, myopathies and bone marrow genetic diseases, suggesting a potential for development of SRP-target therapies of each individual component. For the first time, here we present the current knowledge on the SRP noncanonical functions and raise the need of a deeper understanding of the molecular interactions between SRP and accessory cellular components. We examine diseases associated with SRP components and discuss the development and feasibility of therapeutics targeting individual SRP noncanonical functions.
Collapse
Affiliation(s)
- Camilla Faoro
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Sandro F Ataide
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| |
Collapse
|
28
|
RIPiT-Seq: A tandem immunoprecipitation approach to reveal global binding landscape of multisubunit ribonucleoproteins. Methods Enzymol 2021; 655:401-425. [PMID: 34183131 DOI: 10.1016/bs.mie.2021.03.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
RNA-binding proteins (RBPs) regulate all aspects of RNA metabolism. The ability to identify RNA targets bound by RBPs is critical for understanding RBP function. While powerful techniques are available to identify binding sites of individual RBPs at high resolution, it remains challenging to unravel binding sites of multicomponent ribonucleoproteins (RNPs) where multiple RBPs or proteins function cooperatively to bind to target RNAs. To fill this gap, we have previously developed RNA Immunoprecipitation in Tandem followed by high-throughput sequencing (RIPiT-seq) to characterize RNA targets of compositionally distinct RNP complexes by sequentially immunoprecipitating two proteins from the same RNP and sequencing the co-purifying RNA footprints. Here, we provide an updated and improved protocol for RIPiT-seq. In this protocol, we have used CRISPR-Cas9 to introduce affinity tag to endogenous protein of interest to capture a more representative state of an RNP complex. We present a modified protocol for library preparation for high-throughput sequencing so that it exclusively uses equipment and reagents available in a standard molecular biology lab. This updated custom library preparation protocol is compatible with commercial PCR multiplexing systems for Illumina sequencing platform for simultaneous and cost-effective analysis of large number of samples.
Collapse
|
29
|
Kovalak C, Donovan S, Bicknell AA, Metkar M, Moore MJ. Deep sequencing of pre-translational mRNPs reveals hidden flux through evolutionarily conserved alternative splicing nonsense-mediated decay pathways. Genome Biol 2021; 22:132. [PMID: 33941243 PMCID: PMC8091538 DOI: 10.1186/s13059-021-02309-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/02/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Alternative splicing, which generates multiple mRNA isoforms from single genes, is crucial for the regulation of eukaryotic gene expression. The flux through competing splicing pathways cannot be determined by traditional RNA-Seq, however, because different mRNA isoforms can have widely differing decay rates. Indeed, some mRNA isoforms with extremely short half-lives, such as those subject to translation-dependent nonsense-mediated decay (AS-NMD), may be completely overlooked in even the most extensive RNA-Seq analyses. RESULTS RNA immunoprecipitation in tandem (RIPiT) of exon junction complex components allows for purification of post-splicing mRNA-protein particles (mRNPs) not yet subject to translation (pre-translational mRNPs) and, therefore, translation-dependent mRNA decay. Here we compare exon junction complex RIPiT-Seq to whole cell RNA-Seq data from HEK293 cells. Consistent with expectation, the flux through known AS-NMD pathways is substantially higher than that captured by RNA-Seq. Our RIPiT-Seq also definitively demonstrates that the splicing machinery itself has no ability to detect reading frame. We identify thousands of previously unannotated splicing events; while many can be attributed to splicing noise, others are evolutionarily conserved events that produce new AS-NMD isoforms likely involved in maintenance of protein homeostasis. Several of these occur in genes whose overexpression has been linked to poor cancer prognosis. CONCLUSIONS Deep sequencing of RNAs in post-splicing, pre-translational mRNPs provides a means to identify and quantify splicing events without the confounding influence of differential mRNA decay. For many known AS-NMD targets, the nonsense-mediated decay-linked alternative splicing pathway predominates. Exon junction complex RIPiT-Seq also revealed numerous conserved but previously unannotated AS-NMD events.
Collapse
Affiliation(s)
- Carrie Kovalak
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Scott Donovan
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA
| | - Alicia A Bicknell
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA
| | - Mihir Metkar
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA
| | - Melissa J Moore
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
- Present Address: Moderna, 200 Technology Square, Cambridge, MA, 02139, USA.
| |
Collapse
|
30
|
Zhang P, Ying W, Wu B, Liu R, Wang H, Wang X, Lu Y. Complete IFN-γR1 Deficiency in a Boy Due to UPD(6)mat with IFNGR1 Novel Splicing Variant. J Clin Immunol 2021; 41:834-836. [PMID: 33501617 DOI: 10.1007/s10875-021-00970-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/11/2021] [Indexed: 12/18/2022]
Affiliation(s)
- Ping Zhang
- Center for Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China
| | - Wenjing Ying
- Department of Allergy and Clinical Immunology, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China
| | - Bingbing Wu
- Center for Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China
| | - Renchao Liu
- Center for Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China
| | - Huijun Wang
- Center for Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China
| | - Xiaochuan Wang
- Department of Allergy and Clinical Immunology, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China.
| | - Yulan Lu
- Center for Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China.
| |
Collapse
|
31
|
Kwon OS, Mishra R, Safieddine A, Coleno E, Alasseur Q, Faucourt M, Barbosa I, Bertrand E, Spassky N, Le Hir H. Exon junction complex dependent mRNA localization is linked to centrosome organization during ciliogenesis. Nat Commun 2021; 12:1351. [PMID: 33649372 PMCID: PMC7921557 DOI: 10.1038/s41467-021-21590-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 01/14/2021] [Indexed: 12/17/2022] Open
Abstract
Exon junction complexes (EJCs) mark untranslated spliced mRNAs and are crucial for the mRNA lifecycle. An imbalance in EJC dosage alters mouse neural stem cell (mNSC) division and is linked to human neurodevelopmental disorders. In quiescent mNSC and immortalized human retinal pigment epithelial (RPE1) cells, centrioles form a basal body for ciliogenesis. Here, we report that EJCs accumulate at basal bodies of mNSC or RPE1 cells and decline when these cells differentiate or resume growth. A high-throughput smFISH screen identifies two transcripts accumulating at centrosomes in quiescent cells, NIN and BICD2. In contrast to BICD2, the localization of NIN transcripts is EJC-dependent. NIN mRNA encodes a core component of centrosomes required for microtubule nucleation and anchoring. We find that EJC down-regulation impairs both pericentriolar material organization and ciliogenesis. An EJC-dependent mRNA trafficking towards centrosome and basal bodies might contribute to proper mNSC division and brain development. Exon junction complexes (EJCs) that mark untranslated mRNA are involved in transport, translation and nonsense-mediated mRNA decay. Here the authors show centrosomal localization of EJCs which appears to be required for both the localization of NIN mRNA around centrosomes and ciliogenesis.
Collapse
Affiliation(s)
- Oh Sung Kwon
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Rahul Mishra
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Adham Safieddine
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.,Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, Montpellier, France
| | - Emeline Coleno
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.,Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, Montpellier, France
| | - Quentin Alasseur
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Marion Faucourt
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Isabelle Barbosa
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.,Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, Montpellier, France
| | - Nathalie Spassky
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Hervé Le Hir
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.
| |
Collapse
|
32
|
Mateu-Regué À, Nielsen FC, Christiansen J. Cytoplasmic mRNPs revisited: Singletons and condensates. Bioessays 2020; 42:e2000097. [PMID: 33145808 DOI: 10.1002/bies.202000097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/04/2020] [Indexed: 01/01/2023]
Abstract
Cytoplasmic messenger ribonucleoprotein particles (mRNPs) represent the cellular transcriptome, and recent data have challenged our current understanding of their architecture, transport, and complexity before translation. Pre-translational mRNPs are composed of a single transcript, whereas P-bodies and stress granules are condensates. Both pre-translational mRNPs and actively translating mRNPs seem to adopt a linear rather than a closed-loop configuration. Moreover, assembly of pre-translational mRNPs in physical RNA regulons is an unlikely event, and co-regulated translation may occur locally following extracellular cues. We envisage a stochastic mRNP transport mechanism where translational repression of single mRNPs-in combination with microtubule-mediated cytoplasmic streaming and docking events-are prerequisites for local translation, rather than direct transport.
Collapse
Affiliation(s)
| | | | - Jan Christiansen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
33
|
Dou Y, Barbosa I, Jiang H, Iasillo C, Molloy KR, Schulze WM, Cusack S, Schmid M, Le Hir H, LaCava J, Jensen TH. NCBP3 positively impacts mRNA biogenesis. Nucleic Acids Res 2020; 48:10413-10427. [PMID: 32960271 PMCID: PMC7544205 DOI: 10.1093/nar/gkaa744] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/19/2020] [Accepted: 08/26/2020] [Indexed: 12/26/2022] Open
Abstract
The nuclear Cap-Binding Complex (CBC), consisting of Nuclear Cap-Binding Protein 1 (NCBP1) and 2 (NCBP2), associates with the nascent 5′cap of RNA polymerase II transcripts and impacts RNA fate decisions. Recently, the C17orf85 protein, also called NCBP3, was suggested to form an alternative CBC by replacing NCBP2. However, applying protein–protein interaction screening of NCBP1, 2 and 3, we find that the interaction profile of NCBP3 is distinct. Whereas NCBP1 and 2 identify known CBC interactors, NCBP3 primarily interacts with components of the Exon Junction Complex (EJC) and the TRanscription and EXport (TREX) complex. NCBP3-EJC association in vitro and in vivo requires EJC core integrity and the in vivo RNA binding profiles of EJC and NCBP3 overlap. We further show that NCBP3 competes with the RNA degradation factor ZC3H18 for binding CBC-bound transcripts, and that NCBP3 positively impacts the nuclear export of polyadenylated RNAs and the expression of large multi-exonic transcripts. Collectively, our results place NCBP3 with the EJC and TREX complexes in supporting mRNA expression.
Collapse
Affiliation(s)
- Yuhui Dou
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Aarhus 8000, Denmark
| | - Isabelle Barbosa
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Hua Jiang
- Laboratory of Cellular and Structural Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Claudia Iasillo
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Aarhus 8000, Denmark
| | - Kelly R Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Wiebke Manuela Schulze
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, Grenoble Cedex 9 38042, France
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, Grenoble Cedex 9 38042, France
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Aarhus 8000, Denmark
| | - Hervé Le Hir
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.,European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen 9713 AV, Netherlands
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Aarhus 8000, Denmark
| |
Collapse
|
34
|
Gerbracht JV, Boehm V, Britto-Borges T, Kallabis S, Wiederstein JL, Ciriello S, Aschemeier DU, Krüger M, Frese CK, Altmüller J, Dieterich C, Gehring NH. CASC3 promotes transcriptome-wide activation of nonsense-mediated decay by the exon junction complex. Nucleic Acids Res 2020; 48:8626-8644. [PMID: 32621609 PMCID: PMC7470949 DOI: 10.1093/nar/gkaa564] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/20/2020] [Accepted: 07/01/2020] [Indexed: 01/08/2023] Open
Abstract
The exon junction complex (EJC) is an essential constituent and regulator of spliced messenger ribonucleoprotein particles (mRNPs) in metazoans. As a core component of the EJC, CASC3 was described to be pivotal for EJC-dependent nuclear and cytoplasmic processes. However, recent evidence suggests that CASC3 functions differently from other EJC core proteins. Here, we have established human CASC3 knockout cell lines to elucidate the cellular role of CASC3. In the knockout cells, overall EJC composition and EJC-dependent splicing are unchanged. A transcriptome-wide analysis reveals that hundreds of mRNA isoforms targeted by nonsense-mediated decay (NMD) are upregulated. Mechanistically, recruiting CASC3 to reporter mRNAs by direct tethering or via binding to the EJC stimulates mRNA decay and endonucleolytic cleavage at the termination codon. Building on existing EJC-NMD models, we propose that CASC3 equips the EJC with the persisting ability to communicate with the NMD machinery in the cytoplasm. Collectively, our results characterize CASC3 as a peripheral EJC protein that tailors the transcriptome by promoting the degradation of EJC-dependent NMD substrates.
Collapse
Affiliation(s)
| | - Volker Boehm
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Thiago Britto-Borges
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, University of Heidelberg, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Sebastian Kallabis
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janica L Wiederstein
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Simona Ciriello
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | | | - Marcus Krüger
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Christian K Frese
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, University of Heidelberg, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| |
Collapse
|
35
|
The Branched Nature of the Nonsense-Mediated mRNA Decay Pathway. Trends Genet 2020; 37:143-159. [PMID: 33008628 DOI: 10.1016/j.tig.2020.08.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is a conserved translation-coupled quality control mechanism in all eukaryotes that regulates the expression of a significant fraction of both the aberrant and normal transcriptomes. In vertebrates, NMD has become an essential process owing to expansion of the diversity of NMD-regulated transcripts, particularly during various developmental processes. Surprisingly, however, some core NMD factors that are essential for NMD in simpler organisms appear to be dispensable for vertebrate NMD. At the same time, numerous NMD enhancers and suppressors have been identified in multicellular organisms including vertebrates. Collectively, the available data suggest that vertebrate NMD is a complex, branched pathway wherein individual branches regulate specific mRNA subsets to fulfill distinct physiological functions.
Collapse
|
36
|
Patton RD, Sanjeev M, Woodward LA, Mabin JW, Bundschuh R, Singh G. Chemical crosslinking enhances RNA immunoprecipitation for efficient identification of binding sites of proteins that photo-crosslink poorly with RNA. RNA (NEW YORK, N.Y.) 2020; 26:1216-1233. [PMID: 32467309 PMCID: PMC7430673 DOI: 10.1261/rna.074856.120] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 05/17/2020] [Indexed: 05/14/2023]
Abstract
In eukaryotic cells, proteins that associate with RNA regulate its activity to control cellular function. To fully illuminate the basis of RNA function, it is essential to identify such RNA-associated proteins, their mode of action on RNA, and their preferred RNA targets and binding sites. By analyzing catalogs of human RNA-associated proteins defined by ultraviolet light (UV)-dependent and -independent approaches, we classify these proteins into two major groups: (i) the widely recognized RNA binding proteins (RBPs), which bind RNA directly and UV-crosslink efficiently to RNA, and (ii) a new group of RBP-associated factors (RAFs), which bind RNA indirectly via RBPs and UV-crosslink poorly to RNA. As the UV crosslinking and immunoprecipitation followed by sequencing (CLIP-seq) approach will be unsuitable to identify binding sites of RAFs, we show that formaldehyde crosslinking stabilizes RAFs within ribonucleoproteins to allow for their immunoprecipitation under stringent conditions. Using an RBP (CASC3) and an RAF (RNPS1) within the exon junction complex (EJC) as examples, we show that formaldehyde crosslinking combined with RNA immunoprecipitation in tandem followed by sequencing (xRIPiT-seq) far exceeds CLIP-seq to identify binding sites of RNPS1. xRIPiT-seq reveals that RNPS1 occupancy is increased on exons immediately upstream of strong recursively spliced exons, which depend on the EJC for their inclusion.
Collapse
Affiliation(s)
- Robert D Patton
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Manu Sanjeev
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Lauren A Woodward
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Justin W Mabin
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ralf Bundschuh
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
| | - Guramrit Singh
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| |
Collapse
|
37
|
Lee W, Huang DS, Han K. Constructing cancer patient-specific and group-specific gene networks with multi-omics data. BMC Med Genomics 2020; 13:81. [PMID: 32854705 PMCID: PMC7450550 DOI: 10.1186/s12920-020-00736-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 06/05/2020] [Indexed: 12/26/2022] Open
Abstract
Background Cancer is a complex and heterogeneous disease with many possible genetic and environmental causes. The same treatment for patients of the same cancer type often results in different outcomes in terms of efficacy and side effects of the treatment. Thus, the molecular characterization of individual cancer patients is increasingly important to find an effective treatment. Recently a few methods have been developed to construct cancer sample-specific gene networks based on the difference in the mRNA expression levels between the cancer sample and reference samples. Methods We constructed a patient-specific network with multi-omics data based on the difference between a reference network and a perturbed reference network by the patient. A network specific to a group of patients was obtained using the average change in correlation coefficients and node degree of patient-specific networks of the group. Results In this paper, we present a new method for constructing cancer patient-specific and group-specific gene networks with multi-omics data. The main differences of our method from previous ones are as follows: (1) networks are constructed with multi-omics (mRNA expression, copy number variation, DNA methylation and microRNA expression) data rather than with mRNA expression data alone, (2) background networks are constructed with both normal samples and cancer samples of the specified type to extract cancer-specific gene correlations, and (3) both patient individual-specific networks and patient group-specific networks can be constructed. The results of evaluating our method with several types of cancer show that it constructs more informative and accurate gene networks than previous methods. Conclusions The results of evaluating our method with extensive data of seven cancer types show that the difference of gene correlations between the reference samples and a patient sample is a more predictive feature than mRNA expression levels and that gene networks constructed with multi-omics data show a better performance than those with single omics data in predicting cancer for most cancer types. Our approach will be useful for finding genes and gene pairs to tailor treatments to individual characteristics.
Collapse
Affiliation(s)
- Wook Lee
- Department of Computer Engineering, Inha University, Incheon, 22212, South Korea
| | - De-Shuang Huang
- Institute of Machine Learning and Systems Biology, School of Electronics and Information Engineering, Tongji University, Shanghai, 201804, China
| | - Kyungsook Han
- Department of Computer Engineering, Inha University, Incheon, 22212, South Korea.
| |
Collapse
|
38
|
Tan K, Jones SH, Lake BB, Chousal JN, Shum EY, Zhang L, Chen S, Sohni A, Pandya S, Gallo RL, Zhang K, Cook-Andersen H, Wilkinson MF. The role of the NMD factor UPF3B in olfactory sensory neurons. eLife 2020; 9:e57525. [PMID: 32773035 PMCID: PMC7452722 DOI: 10.7554/elife.57525] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/09/2020] [Indexed: 12/13/2022] Open
Abstract
The UPF3B-dependent branch of the nonsense-mediated RNA decay (NMD) pathway is critical for human cognition. Here, we examined the role of UPF3B in the olfactory system. Single-cell RNA-sequencing (scRNA-seq) analysis demonstrated considerable heterogeneity of olfactory sensory neuron (OSN) cell populations in wild-type (WT) mice, and revealed that UPF3B loss influences specific subsets of these cell populations. UPF3B also regulates the expression of a large cadre of antimicrobial genes in OSNs, and promotes the selection of specific olfactory receptor (Olfr) genes for expression in mature OSNs (mOSNs). RNA-seq and Ribotag analyses identified classes of mRNAs expressed and translated at different levels in WT and Upf3b-null mOSNs. Integrating multiple computational approaches, UPF3B-dependent NMD target transcripts that are candidates to mediate the functions of NMD in mOSNs were identified in vivo. Together, our data provides a valuable resource for the olfactory field and insights into the roles of NMD in vivo.
Collapse
Affiliation(s)
- Kun Tan
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Samantha H Jones
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Blue B Lake
- Department of Bioengineering, University of California, San DiegoSan DiegoUnited States
| | - Jennifer N Chousal
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Eleen Y Shum
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Lingjuan Zhang
- Department of Dermatology, University of California, San DiegoSan DiegoUnited States
| | - Song Chen
- Department of Bioengineering, University of California, San DiegoSan DiegoUnited States
| | - Abhishek Sohni
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Shivam Pandya
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Richard L Gallo
- Department of Dermatology, University of California, San DiegoSan DiegoUnited States
| | - Kun Zhang
- Department of Bioengineering, University of California, San DiegoSan DiegoUnited States
| | - Heidi Cook-Andersen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
- Division of Biological Sciences, University of California, San DiegoSan DiegoUnited States
| | - Miles F Wilkinson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
- Institute of Genomic Medicine, University of California, San DiegoSan DiegoUnited States
| |
Collapse
|
39
|
Lavysh D, Neu-Yilik G. UPF1-Mediated RNA Decay-Danse Macabre in a Cloud. Biomolecules 2020; 10:E999. [PMID: 32635561 PMCID: PMC7407380 DOI: 10.3390/biom10070999] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/18/2020] [Accepted: 06/29/2020] [Indexed: 12/21/2022] Open
Abstract
Nonsense-mediated RNA decay (NMD) is the prototype example of a whole family of RNA decay pathways that unfold around a common central effector protein called UPF1. While NMD in yeast appears to be a linear pathway, NMD in higher eukaryotes is a multifaceted phenomenon with high variability with respect to substrate RNAs, degradation efficiency, effector proteins and decay-triggering RNA features. Despite increasing knowledge of the mechanistic details, it seems ever more difficult to define NMD and to clearly distinguish it from a growing list of other UPF1-mediated RNA decay pathways (UMDs). With a focus on mammalian, we here critically examine the prevailing NMD models and the gaps and inconsistencies in these models. By exploring the minimal requirements for NMD and other UMDs, we try to elucidate whether they are separate and definable pathways, or rather variations of the same phenomenon. Finally, we suggest that the operating principle of the UPF1-mediated decay family could be considered similar to that of a computing cloud providing a flexible infrastructure with rapid elasticity and dynamic access according to specific user needs.
Collapse
Affiliation(s)
- Daria Lavysh
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany;
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
- Department Clinical Pediatric Oncology, Hopp Kindertumorzentrum am NCT Heidelberg, 69120 Heidelberg, Germany
| | - Gabriele Neu-Yilik
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany;
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
- Department Clinical Pediatric Oncology, Hopp Kindertumorzentrum am NCT Heidelberg, 69120 Heidelberg, Germany
| |
Collapse
|
40
|
A Day in the Life of the Exon Junction Complex. Biomolecules 2020; 10:biom10060866. [PMID: 32517083 PMCID: PMC7355637 DOI: 10.3390/biom10060866] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 12/12/2022] Open
Abstract
The exon junction complex (EJC) is an abundant messenger ribonucleoprotein (mRNP) component that is assembled during splicing and binds to mRNAs upstream of exon-exon junctions. EJCs accompany the mRNA during its entire life in the nucleus and the cytoplasm and communicate the information about the splicing process and the position of introns. Specifically, the EJC’s core components and its associated proteins regulate different steps of gene expression, including pre-mRNA splicing, mRNA export, translation, and nonsense-mediated mRNA decay (NMD). This review summarizes the most important functions and main protagonists in the life of the EJC. It also provides an overview of the latest findings on the assembly, composition and molecular activities of the EJC and presents them in the chronological order, in which they play a role in the EJC’s life cycle.
Collapse
|
41
|
Gangras P, Gallagher TL, Parthun MA, Yi Z, Patton RD, Tietz KT, Deans NC, Bundschuh R, Amacher SL, Singh G. Zebrafish rbm8a and magoh mutants reveal EJC developmental functions and new 3'UTR intron-containing NMD targets. PLoS Genet 2020; 16:e1008830. [PMID: 32502192 PMCID: PMC7310861 DOI: 10.1371/journal.pgen.1008830] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 06/23/2020] [Accepted: 05/05/2020] [Indexed: 12/11/2022] Open
Abstract
Many post-transcriptional mechanisms operate via mRNA 3'UTRs to regulate protein expression, and such controls are crucial for development. We show that homozygous mutations in two zebrafish exon junction complex (EJC) core genes rbm8a and magoh leads to muscle disorganization, neural cell death, and motor neuron outgrowth defects, as well as dysregulation of mRNAs subjected to nonsense-mediated mRNA decay (NMD) due to translation termination ≥ 50 nts upstream of the last exon-exon junction. Intriguingly, we find that EJC-dependent NMD also regulates a subset of transcripts that contain 3'UTR introns (3'UI) < 50 nts downstream of a stop codon. Some transcripts containing such stop codon-proximal 3'UI are also NMD-sensitive in cultured human cells and mouse embryonic stem cells. We identify 167 genes that contain a conserved proximal 3'UI in zebrafish, mouse and humans. foxo3b is one such proximal 3'UI-containing gene that is upregulated in zebrafish EJC mutant embryos, at both mRNA and protein levels, and loss of foxo3b function in EJC mutant embryos significantly rescues motor axon growth defects. These data are consistent with EJC-dependent NMD regulating foxo3b mRNA to control protein expression during zebrafish development. Our work shows that the EJC is critical for normal zebrafish development and suggests that proximal 3'UIs may serve gene regulatory function in vertebrates.
Collapse
Affiliation(s)
- Pooja Gangras
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| | - Thomas L. Gallagher
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| | - Michael A. Parthun
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| | - Zhongxia Yi
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| | - Robert D. Patton
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
- Department of Physics, The Ohio State University, Ohio, United States of America
| | - Kiel T. Tietz
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| | - Natalie C. Deans
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
- Department of Physics, The Ohio State University, Ohio, United States of America
- Department of Chemistry and Biochemistry, The Ohio State University, Ohio, United States of America
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Ohio, United States of America
| | - Sharon L. Amacher
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Ohio, United States of America
- Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children’s Hospital, Ohio, United States of America
| | - Guramrit Singh
- Department of Molecular Genetics, The Ohio State University, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| |
Collapse
|
42
|
The Complex Relationship between HTLV-1 and Nonsense-Mediated mRNA Decay (NMD). Pathogens 2020; 9:pathogens9040287. [PMID: 32326562 PMCID: PMC7238105 DOI: 10.3390/pathogens9040287] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/09/2020] [Accepted: 04/12/2020] [Indexed: 02/07/2023] Open
Abstract
Before the establishment of an adaptive immune response, retroviruses can be targeted by several cellular host factors at different stages of the viral replication cycle. This intrinsic immunity relies on a large diversity of antiviral processes. In the case of HTLV-1 infection, these active innate host defense mechanisms are debated. Among these mechanisms, we focused on an RNA decay pathway called nonsense-mediated mRNA decay (NMD), which can target multiple viral RNAs, including HTLV-1 unspliced RNA, as has been recently demonstrated. NMD is a co-translational process that depends on the RNA helicase UPF1 and regulates the expression of multiple types of host mRNAs. RNA sensitivity to NMD depends on mRNA organization and the ribonucleoprotein (mRNP) composition. HTLV-1 has evolved several means to evade the NMD threat, leading to NMD inhibition. In the early steps of infection, NMD inhibition favours the production of HTLV-1 infectious particles, which may contribute to the survival of the fittest clones despite genome instability; however, its direct long-term impact remains to be investigated.
Collapse
|
43
|
Kurosaki T, Popp MW, Maquat LE. Quality and quantity control of gene expression by nonsense-mediated mRNA decay. Nat Rev Mol Cell Biol 2020; 20:406-420. [PMID: 30992545 DOI: 10.1038/s41580-019-0126-2] [Citation(s) in RCA: 415] [Impact Index Per Article: 103.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonsense-mediated mRNA decay (NMD) is one of the best characterized and most evolutionarily conserved cellular quality control mechanisms. Although NMD was first found to target one-third of mutated, disease-causing mRNAs, it is now known to also target ~10% of unmutated mammalian mRNAs to facilitate appropriate cellular responses - adaptation, differentiation or death - to environmental changes. Mutations in NMD genes in humans are associated with intellectual disability and cancer. In this Review, we discuss how NMD serves multiple purposes in human cells by degrading both mutated mRNAs to protect the integrity of the transcriptome and normal mRNAs to control the quantities of unmutated transcripts.
Collapse
Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.,Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Maximilian W Popp
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.,Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA. .,Center for RNA Biology, University of Rochester, Rochester, NY, USA.
| |
Collapse
|
44
|
Rahman MA, Lin KT, Bradley RK, Abdel-Wahab O, Krainer AR. Recurrent SRSF2 mutations in MDS affect both splicing and NMD. Genes Dev 2020; 34:413-427. [PMID: 32001512 PMCID: PMC7050488 DOI: 10.1101/gad.332270.119] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/20/2019] [Indexed: 12/23/2022]
Abstract
Oncogenic mutations in the RNA splicing factors SRSF2, SF3B1, and U2AF1 are the most frequent class of mutations in myelodysplastic syndromes and are also common in clonal hematopoiesis, acute myeloid leukemia, chronic lymphocytic leukemia, and a variety of solid tumors. They cause genome-wide splicing alterations that affect important regulators of hematopoiesis. Several mRNA isoforms promoted by the various splicing factor mutants comprise a premature termination codon (PTC) and are therefore potential targets of nonsense-mediated mRNA decay (NMD). In light of the mechanistic relationship between splicing and NMD, we sought evidence for a specific role of mutant SRSF2 in NMD. We show that SRSF2 Pro95 hot spot mutations elicit enhanced mRNA decay, which is dependent on sequence-specific RNA binding and splicing. SRSF2 mutants enhance the deposition of exon junction complexes (EJCs) downstream from the PTC through RNA-mediated molecular interactions. This architecture then favors the association of key NMD factors to elicit mRNA decay. Gene-specific blocking of EJC deposition by antisense oligonucleotides circumvents aberrant NMD promoted by mutant SRSF2, restoring the expression of PTC-containing transcript. Our study uncovered critical effects of SRSF2 mutants in hematologic malignancies, reflecting the regulation at multiple levels of RNA metabolism, from splicing to decay.
Collapse
Affiliation(s)
| | - Kuan-Ting Lin
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.,Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Omar Abdel-Wahab
- Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| |
Collapse
|
45
|
Zhang Z, Guo M, Liu Y, Liu P, Cao X, Xu Y, Zhu X. RNPS1 inhibition aggravates ischemic brain injury and promotes neuronal death. Biochem Biophys Res Commun 2019; 523:39-45. [PMID: 31831174 DOI: 10.1016/j.bbrc.2019.11.185] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 11/28/2019] [Indexed: 12/13/2022]
Abstract
RNA-binding protein with serine-rich domain 1 (RNPS1) is essential for modulating mRNA metabolism, but its role in ischemic stroke is unknown. In this study, we found that RNPS1 expression was significantly up-regulated in the brains of ischemic stroke mice and primary cortical neurons after oxygen-glucose deprivation (OGD) treatment. Knockdown of RNPS1 significantly aggravated ischemic brain injury after middle cerebral artery occlusion (MCAO) and promoted neuronal death. In addition, knockdown of RNPS1 exacerbated ischemia induced neuronal apoptosis, and downregulated the expression of anti-apoptotic proteins Bcl-xL and Mcl-1. Our study suggested that RNPS1 might be a potential therapeutic target for alleviating neuronal death in ischemic stroke.
Collapse
Affiliation(s)
- Zhi Zhang
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210008, China; Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, 210008, China; Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, China
| | - Mengdi Guo
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210008, China; Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, China
| | - Ying Liu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210008, China; Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, China
| | - Pinyi Liu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210008, China; Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, 210008, China; Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, China
| | - Xiang Cao
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210008, China; Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, China
| | - Yun Xu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210008, China; Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, 210008, China; Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, China
| | - Xiaolei Zhu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210008, China; Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, China.
| |
Collapse
|
46
|
Woodward L, Gangras P, Singh G. Identification of Footprints of RNA:Protein Complexes via RNA Immunoprecipitation in Tandem Followed by Sequencing (RIPiT-Seq). J Vis Exp 2019. [PMID: 31355789 DOI: 10.3791/59913] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
RNA immunoprecipitation in tandem (RIPiT) is a method for enriching RNA footprints of a pair of proteins within an RNA:protein (RNP) complex. RIPiT employs two purification steps. First, immunoprecipitation of a tagged RNP subunit is followed by mild RNase digestion and subsequent non-denaturing affinity elution. A second immunoprecipitation of another RNP subunit allows for enrichment of a defined complex. Following a denaturing elution of RNAs and proteins, the RNA footprints are converted into high-throughput DNA sequencing libraries. Unlike the more popular ultraviolet (UV) crosslinking followed by immunoprecipitation (CLIP) approach to enrich RBP binding sites, RIPiT is UV-crosslinking independent. Hence RIPiT can be applied to numerous proteins present in the RNA interactome and beyond that are essential to RNA regulation but do not directly contact the RNA or UV-crosslink poorly to RNA. The two purification steps in RIPiT provide an additional advantage of identifying binding sites where a protein of interest acts in partnership with another cofactor. The double purification strategy also serves to enhance signal by limiting background. Here, we provide a step-wise procedure to perform RIPiT and to generate high-throughput sequencing libraries from isolated RNA footprints. We also outline RIPiT's advantages and applications and discuss some of its limitations.
Collapse
Affiliation(s)
- Lauren Woodward
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University
| | - Pooja Gangras
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University
| | - Guramrit Singh
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University;
| |
Collapse
|
47
|
Kishor A, Fritz SE, Hogg JR. Nonsense-mediated mRNA decay: The challenge of telling right from wrong in a complex transcriptome. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1548. [PMID: 31131562 DOI: 10.1002/wrna.1548] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/01/2019] [Accepted: 05/07/2019] [Indexed: 12/18/2022]
Abstract
The nonsense-mediated mRNA decay pathway selects and degrades its targets using a dense network of RNA-protein and protein-protein interactions. Together, these interactions allow the pathway to collect copious information about the translating mRNA, including translation termination status, splice junction positions, mRNP composition, and 3'UTR length and structure. The core NMD machinery, centered on the RNA helicase UPF1, integrates this information to determine the efficiency of decay. A picture of NMD is emerging in which many factors contribute to the dynamics of decay complex assembly and disassembly, thereby influencing the probability of decay. The ability of the NMD pathway to recognize mRNP features of diverse potential substrates allows it to simultaneously perform quality control and regulatory functions. In vertebrates, increased transcriptome complexity requires balance between these two functions since high NMD efficiency is desirable for maintenance of quality control fidelity but may impair expression of normal mRNAs. NMD has adapted to this challenge by employing mechanisms to enhance identification of certain potential substrates, while using sequence-specific RNA-binding proteins to shield others from detection. These elaborations on the conserved NMD mechanism permit more sensitive post-transcriptional gene regulation but can have severe deleterious consequences, including the failure to degrade pathogenic aberrant mRNAs in many B cell lymphomas. This article is categorized under: RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms.
Collapse
Affiliation(s)
- Aparna Kishor
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Sarah E Fritz
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - J Robert Hogg
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
48
|
Spatial Organization of Single mRNPs at Different Stages of the Gene Expression Pathway. Mol Cell 2018; 72:727-738.e5. [PMID: 30415950 DOI: 10.1016/j.molcel.2018.10.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/24/2018] [Accepted: 10/04/2018] [Indexed: 12/21/2022]
Abstract
mRNAs form ribonucleoprotein complexes (mRNPs) by association with proteins that are crucial for mRNA metabolism. While the mRNP proteome has been well characterized, little is known about mRNP organization. Using a single-molecule approach, we show that mRNA conformation changes depending on its cellular localization and translational state. Compared to nuclear mRNPs and lncRNPs, association with ribosomes decompacts individual mRNAs, while pharmacologically dissociating ribosomes or sequestering them into stress granules leads to increased compaction. Moreover, translating mRNAs rarely show co-localized 5' and 3' ends, indicating either that mRNAs are not translated in a closed-loop configuration, or that mRNA circularization is transient, suggesting that a stable closed-loop conformation is not a universal state for all translating mRNAs.
Collapse
|