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Zhang R, Karijolich J. RNA recognition by PKR during DNA virus infection. J Med Virol 2024; 96:e29424. [PMID: 38285432 PMCID: PMC10832991 DOI: 10.1002/jmv.29424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/30/2024]
Abstract
Protein kinase R (PKR) is a double-stranded RNA (dsRNA) binding protein that plays a crucial role in innate immunity during viral infection and can restrict both DNA and RNA viruses. The potency of its antiviral function is further reflected by the large number of viral-encoded PKR antagonists. However, much about the regulation of dsRNA accumulation and PKR activation during viral infection remains unknown. Since DNA viruses do not have an RNA genome or RNA replication intermediates like RNA viruses do, PKR-mediated dsRNA detection in the context of DNA virus infection is particularly intriguing. Here, we review the current state of knowledge regarding the regulation of PKR activation and its antagonism during infection with DNA viruses.
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Affiliation(s)
- Ruilin Zhang
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-2363, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt Center for Immunobiology, Nashville. Nashville, TN 37232-2363, USA
| | - John Karijolich
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-2363, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt Center for Immunobiology, Nashville. Nashville, TN 37232-2363, USA
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2
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Kaempfer R. RNA Activators of Stress Kinase PKR within Human Genes That Control Splicing or Translation Create Novel Targets for Hereditary Diseases. Int J Mol Sci 2024; 25:1323. [PMID: 38279321 PMCID: PMC10816128 DOI: 10.3390/ijms25021323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 01/14/2024] [Accepted: 01/20/2024] [Indexed: 01/28/2024] Open
Abstract
Specific sequences within RNA encoded by human genes essential for survival possess the ability to activate the RNA-dependent stress kinase PKR, resulting in phosphorylation of its substrate, eukaryotic translation initiation factor-2α (eIF2α), either to curb their mRNA translation or to enhance mRNA splicing. Thus, interferon-γ (IFNG) mRNA activates PKR through a 5'-terminal 203-nucleotide pseudoknot structure, thereby strongly downregulating its own translation and preventing a harmful hyper-inflammatory response. Tumor necrosis factor-α (TNF) pre-mRNA encodes within the 3'-untranslated region (3'-UTR) a 104-nucleotide RNA pseudoknot that activates PKR to enhance its splicing by an order of magnitude while leaving mRNA translation intact, thereby promoting effective TNF protein expression. Adult and fetal globin genes encode pre-mRNA structures that strongly activate PKR, leading to eIF2α phosphorylation that greatly enhances spliceosome assembly and splicing, yet also structures that silence PKR activation upon splicing to allow for unabated globin mRNA translation essential for life. Regulatory circuits resulting in each case from PKR activation were reviewed previously. Here, we analyze mutations within these genes created to delineate the RNA structures that activate PKR and to deconvolute their folding. Given the critical role of intragenic RNA activators of PKR in gene regulation, such mutations reveal novel potential RNA targets for human disease.
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Affiliation(s)
- Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University, Jerusalem 9112102, Israel
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3
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Boone M, Zappa F. Signaling plasticity in the integrated stress response. Front Cell Dev Biol 2023; 11:1271141. [PMID: 38143923 PMCID: PMC10740175 DOI: 10.3389/fcell.2023.1271141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/29/2023] [Indexed: 12/26/2023] Open
Abstract
The Integrated Stress Response (ISR) is an essential homeostatic signaling network that controls the cell's biosynthetic capacity. Four ISR sensor kinases detect multiple stressors and relay this information to downstream effectors by phosphorylating a common node: the alpha subunit of the eukaryotic initiation factor eIF2. As a result, general protein synthesis is repressed while select transcripts are preferentially translated, thus remodeling the proteome and transcriptome. Mounting evidence supports a view of the ISR as a dynamic signaling network with multiple modulators and feedback regulatory features that vary across cell and tissue types. Here, we discuss updated views on ISR sensor kinase mechanisms, how the subcellular localization of ISR components impacts signaling, and highlight ISR signaling differences across cells and tissues. Finally, we consider crosstalk between the ISR and other signaling pathways as a determinant of cell health.
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4
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Kaempfer R. Positive Regulation of Splicing of Cellular and Viral mRNA by Intragenic RNA Elements That Activate the Stress Kinase PKR, an Antiviral Mechanism. Genes (Basel) 2023; 14:genes14050974. [PMID: 37239334 DOI: 10.3390/genes14050974] [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: 02/13/2023] [Revised: 04/03/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
The transient activation of the cellular stress kinase, protein kinase RNA-activated (PKR), by double-helical RNA, especially by viral double-stranded RNA generated during replication, results in the inhibition of translation via the phosphorylation of eukaryotic initiation factor 2 α-chain (eIF2α). Exceptionally, short intragenic elements within primary transcripts of the human tumor necrosis factor (TNF-α) and globin genes, genes essential for survival, can form RNA structures that strongly activate PKR and thereby render the splicing of their mRNAs highly efficient. These intragenic RNA activators of PKR promote early spliceosome assembly and splicing by inducing phosphorylation of nuclear eIF2α, without impairing the translation of the mature spliced mRNA. Unexpectedly, excision of the large human immunodeficiency virus (HIV) rev/tat intron was shown to require activation of PKR by the viral RNA and eIF2α phosphorylation. The splicing of rev/tat mRNA is abrogated by viral antagonists of PKR and by trans-dominant negative mutant PKR, yet enhanced by the overexpression of PKR. The TNFα and HIV RNA activators of PKR fold into compact pseudoknots that are highly conserved within the phylogeny, supporting their essential role in the upregulation of splicing. HIV provides the first example of a virus co-opting a major cellular antiviral mechanism, the activation of PKR by its RNA, to promote splicing.
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Affiliation(s)
- Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 9112102, Israel
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5
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Namer LS, Harwig A, Heynen SP, Das AT, Berkhout B, Kaempfer R. HIV co-opts a cellular antiviral mechanism, activation of stress kinase PKR by its RNA, to enable splicing of rev/tat mRNA. Cell Biosci 2023; 13:28. [PMID: 36774495 PMCID: PMC9922466 DOI: 10.1186/s13578-023-00972-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/24/2023] [Indexed: 02/13/2023] Open
Abstract
BACKGROUND Activation of RNA-dependent stress kinase PKR, especially by viral double-stranded RNA, induces eukaryotic initiation factor 2 α-chain (eIF2α) phosphorylation, attenuating thereby translation. We report that this RNA-mediated negative control mechanism, considered a cornerstone of the cell's antiviral response, positively regulates splicing of a viral mRNA. RESULTS Excision of the large human immunodeficiency virus (HIV) rev/tat intron depends strictly on activation of PKR by the viral RNA and on eIF2α phosphorylation. Rev/tat mRNA splicing was blocked by viral PKR antagonists Vaccinia E3L and Ebola VP35, as well as by a trans-dominant negative mutant of PKR, yet enhanced by overexpressing PKR. Expression of non-phosphorylatable mutant eIF2αS51A, but not of wild type eIF2α, abrogated efficient splicing of rev/tat mRNA. By contrast, expression of eIF2αS51D, a phosphomimetic mutant of eIF2α, left rev/tat mRNA splicing intact. Unlike eIF2αS51A, eIF2αS51D does not inhibit eIF2α phosphorylation by activated PKR. All HIV mRNA species contain terminal trans-activation response (TAR) stem-loop sequences that potentially could activate PKR, yet even upon TAR deletion, HIV mRNA production remained sensitive to inhibitors of PKR activation. Bioinformatic and mutational analyses revealed a compact RNA pseudoknot upstream of 3'-terminal TAR that promotes splicing by activating PKR. Supporting its essential role in control of splicing, this pseudoknot is conserved among diverse HIV and nonhuman primate SIVcpz isolates. The pseudoknot and 3'-terminal TAR collaborate in mediating PKR-regulated splicing of rev/tat intron, the pseudoknot being dominant. CONCLUSIONS Our results on HIV provide the first example of a virus co-opting activation of PKR by its RNA, a cellular antiviral mechanism, to promote splicing. They raise the question whether other viruses may use local activation of host kinase PKR through RNA elements within their genome to achieve efficient splicing of their mRNA. Our experiments reveal an indispensable role for eIF2α phosphorylation in HIV rev/tat mRNA splicing that accounts for the need for PKR activation.
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Affiliation(s)
- Lise Sarah Namer
- grid.9619.70000 0004 1937 0538Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, 9112102 Jerusalem, Israel
| | - Alex Harwig
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Stephan P. Heynen
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Atze T. Das
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Ben Berkhout
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel.
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6
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Interferon-gamma modulates articular chondrocyte and osteoblast metabolism through protein kinase R-independent and dependent mechanisms. Biochem Biophys Rep 2022; 32:101323. [PMID: 36105611 PMCID: PMC9464860 DOI: 10.1016/j.bbrep.2022.101323] [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: 06/13/2022] [Revised: 07/20/2022] [Accepted: 08/01/2022] [Indexed: 11/23/2022] Open
Abstract
Osteoarthritis (OA) affects multiple tissues of the synovial joint and is characterised by articular cartilage degeneration and bone remodelling. Interferon-γ (IFN-γ) is implicated in osteoarthritis pathology exerting its biological effects via various mechanisms including activation of protein kinase R (PKR), which has been implicated in inflammation and arthritis. This study investigated whether treatment of articular cartilage chondrocytes and osteoblasts with IFN-γ could induce a degradative phenotype that was mediated through the PKR signalling pathway. IFN-γ treatment of chondrocytes increased transcription of key inflammatory mediators (TNF-α, IL-6), matrix degrading enzymes (MMP-13), the transcription factor STAT1, and PKR. Activation of PKR was involved in the regulation of TNF-α, IL-6, and STAT1. In osteoblasts, IFN-γ increased human and mouse STAT1, and human IL-6 through a mechanism involving PKR. ALP, COL1A1 (human and mouse), RUNX2 (mouse), and PHOSPHO1 (mouse) were decreased by IFN-γ. The number of PKR positive cells were increased in post-traumatic OA (PTOA). This study has revealed that IFN-γ propagates inflammatory and degenerative events in articular chondrocytes and osteoblasts via PKR activation. Since IFN-γ and PKR signalling are both activated in early PTOA, these mechanisms are likely to contribute to joint degeneration after injury and might offer attractive targets for therapeutic intervention. •IFN-γ treatment of chondrocytes increased transcription of TNF-α, IL-6, and STAT1 via PKR activation. •In osteoblasts, IFN-γ increased STAT1 and IL-6 via PKR activation. •The number of PKR positive cells were increased in post-traumatic OA (PTOA). •IFN-γ propagates inflammatory and degenerative events in articular chondrocytes and osteoblasts via PKR activation. •IFN-γ and PKR signalling are both activated in early PTOA and are likely to contribute to joint degeneration after injury.
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7
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Price AM, Steinbock RT, Di C, Hayer K, Li Y, Herrmann C, Parenti N, Whelan J, Weiss S, Weitzman M. Adenovirus prevents dsRNA formation by promoting efficient splicing of viral RNA. Nucleic Acids Res 2022; 50:1201-1220. [PMID: 34671803 PMCID: PMC8860579 DOI: 10.1093/nar/gkab896] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/10/2021] [Accepted: 10/08/2021] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cells recognize intracellular pathogens through pattern recognition receptors, including sensors of aberrant nucleic acid structures. Sensors of double-stranded RNA (dsRNA) are known to detect replication intermediates of RNA viruses. It has long been suggested that annealing of mRNA from symmetrical transcription of both top and bottom strands of DNA virus genomes can produce dsRNA during infection. Supporting this hypothesis, nearly all DNA viruses encode inhibitors of dsRNA-recognition pathways. However, direct evidence that DNA viruses produce dsRNA is lacking. Contrary to dogma, we show that the nuclear-replicating DNA virus adenovirus (AdV) does not produce detectable levels of dsRNA during infection. In contrast, abundant dsRNA is detected within the nucleus of cells infected with AdV mutants defective for viral RNA processing. In the presence of nuclear dsRNA, the cytoplasmic dsRNA sensor PKR is relocalized and activated within the nucleus. Accumulation of viral dsRNA occurs in the late phase of infection, when unspliced viral transcripts form intron/exon base pairs between top and bottom strand transcripts. We propose that DNA viruses actively limit dsRNA formation by promoting efficient splicing and mRNA processing, thus avoiding detection and restriction by host innate immune sensors of pathogenic nucleic acids.
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Affiliation(s)
- Alexander M Price
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Robert T Steinbock
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Cell & Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Chao Di
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Katharina E Hayer
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Yize Li
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christin Herrmann
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Cell & Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Nicholas A Parenti
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jillian N Whelan
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Susan R Weiss
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew D Weitzman
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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8
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Nicolet BP, Zandhuis ND, Lattanzio VM, Wolkers MC. Sequence determinants as key regulators in gene expression of T cells. Immunol Rev 2021; 304:10-29. [PMID: 34486113 PMCID: PMC9292449 DOI: 10.1111/imr.13021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/09/2021] [Accepted: 08/17/2021] [Indexed: 12/12/2022]
Abstract
T cell homeostasis, T cell differentiation, and T cell effector function rely on the constant fine-tuning of gene expression. To alter the T cell state, substantial remodeling of the proteome is required. This remodeling depends on the intricate interplay of regulatory mechanisms, including post-transcriptional gene regulation. In this review, we discuss how the sequence of a transcript influences these post-transcriptional events. In particular, we review how sequence determinants such as sequence conservation, GC content, and chemical modifications define the levels of the mRNA and the protein in a T cell. We describe the effect of different forms of alternative splicing on mRNA expression and protein production, and their effect on subcellular localization. In addition, we discuss the role of sequences and structures as binding hubs for miRNAs and RNA-binding proteins in T cells. The review thus highlights how the intimate interplay of post-transcriptional mechanisms dictate cellular fate decisions in T cells.
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Affiliation(s)
- Benoit P. Nicolet
- Department of HematopoiesisSanquin Research and Landsteiner LaboratoryAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
| | - Nordin D. Zandhuis
- Department of HematopoiesisSanquin Research and Landsteiner LaboratoryAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
| | - V. Maria Lattanzio
- Department of HematopoiesisSanquin Research and Landsteiner LaboratoryAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
| | - Monika C. Wolkers
- Department of HematopoiesisSanquin Research and Landsteiner LaboratoryAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
- Oncode InstituteUtrechtThe Netherlands
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9
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Curdy N, Lanvin O, Cadot S, Laurent C, Fournié JJ, Franchini DM. Stress Granules in the Post-transcriptional Regulation of Immune Cells. Front Cell Dev Biol 2021; 8:611185. [PMID: 33520991 PMCID: PMC7841200 DOI: 10.3389/fcell.2020.611185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022] Open
Abstract
Immune cell activation triggers transcriptional and translational programs eliciting cellular processes, such as differentiation or proliferation, essential for an efficient immune response. These dynamic processes require an intricate orchestration of regulatory mechanisms to control the precise spatiotemporal expression of proteins. Post-transcriptional regulation ensures the control of messenger RNA metabolism and appropriate translation. Among these post-transcriptional regulatory mechanisms, stress granules participate in the control of protein synthesis. Stress granules are ribonucleoprotein complexes that form upon stress, typically under control of the integrated stress response. Such structures assemble upon stimulation of immune cells where they control selective translational programs ensuring the establishment of accurate effector functions. In this review, we summarize the current knowledge about post-transcriptional regulation in immune cells and highlight the role of stress sensors and stress granules in such regulation.
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Affiliation(s)
- Nicolas Curdy
- Cancer Research Center of Toulouse (CRCT), INSERM UMR 1037, CNRS ERL 5294, Toulouse, France.,Université Toulouse III Paul Sabatier, Toulouse, France.,Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Olivia Lanvin
- Cancer Research Center of Toulouse (CRCT), INSERM UMR 1037, CNRS ERL 5294, Toulouse, France.,Université Toulouse III Paul Sabatier, Toulouse, France.,Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Sarah Cadot
- Cancer Research Center of Toulouse (CRCT), INSERM UMR 1037, CNRS ERL 5294, Toulouse, France.,Université Toulouse III Paul Sabatier, Toulouse, France.,Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Camille Laurent
- Cancer Research Center of Toulouse (CRCT), INSERM UMR 1037, CNRS ERL 5294, Toulouse, France.,Université Toulouse III Paul Sabatier, Toulouse, France.,Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France.,Département de Pathologie, Centre Hospitalier Universitaire (CHU) de Toulouse, Toulouse, France
| | - Jean-Jacques Fournié
- Cancer Research Center of Toulouse (CRCT), INSERM UMR 1037, CNRS ERL 5294, Toulouse, France.,Université Toulouse III Paul Sabatier, Toulouse, France.,Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Don-Marc Franchini
- Cancer Research Center of Toulouse (CRCT), INSERM UMR 1037, CNRS ERL 5294, Toulouse, France.,Université Toulouse III Paul Sabatier, Toulouse, France.,Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
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10
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Chen Y, Shen J. Mucosal immunity and tRNA, tRF, and tiRNA. J Mol Med (Berl) 2020; 99:47-56. [PMID: 33200232 DOI: 10.1007/s00109-020-02008-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/15/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022]
Abstract
Mucosal immunity has crucial roles in human diseases such as respiratory tract infection, inflammatory bowel diseases (IBD), and colorectal cancer (CRC). Recent studies suggest that the mononuclear phagocyte system, cancer cells, bacteria, and viruses induce the mucosal immune reaction by various pathways, and can be major factors in the pathogenesis of these diseases. Transfer RNA (tRNA) and its fragments, including tRNA-derived RNA fragments (tRFs) and tRNA-derived stress-induced RNAs (tiRNAs), have emerged as a hot topic in recent years. They not only are verified as essential for transcription and translation but also play roles in cellular homeostasis and functions, such as cell metastasis, proliferation, and apoptosis. However, the specific relationship between their biological regulation and mucosal immunity remains unclear to date. In the present review, we carry out a comprehensive discussion on the specific roles of tRNA, tRFs, and tiRNAs relevant to mucosal immunity and related diseases.
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Affiliation(s)
- Yueying Chen
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Inflammatory Bowel Disease Research Center, 160# Pu Jian Ave, Shanghai, 200127, China
- Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160# Pu Jian Ave, Shanghai, 200127, China
- Shanghai Institute of Digestive Disease, 160# Pu Jian Ave, Shanghai, 200127, China
| | - Jun Shen
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Inflammatory Bowel Disease Research Center, 160# Pu Jian Ave, Shanghai, 200127, China.
- Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160# Pu Jian Ave, Shanghai, 200127, China.
- Shanghai Institute of Digestive Disease, 160# Pu Jian Ave, Shanghai, 200127, China.
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11
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Salem ESB, Vonberg AD, Borra VJ, Gill RK, Nakamura T. RNAs and RNA-Binding Proteins in Immuno-Metabolic Homeostasis and Diseases. Front Cardiovasc Med 2019; 6:106. [PMID: 31482095 PMCID: PMC6710452 DOI: 10.3389/fcvm.2019.00106] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/17/2019] [Indexed: 12/16/2022] Open
Abstract
The increasing prevalence of worldwide obesity has emerged as a major risk factor for type 2 diabetes (T2D), hepatosteatosis, and cardiovascular disease. Accumulating evidence indicates that obesity has strong inflammatory underpinnings tightly linked to the development of metabolic diseases. However, the molecular mechanisms by which obesity induces aberrant inflammation associated with metabolic diseases are not yet clearly defined. Recently, RNAs have emerged as important regulators of stress responses and metabolism. RNAs are subject to changes in modification status, higher-order structure, and cellular localization; all of which could affect the affinity for RNA-binding proteins (RBPs) and thereby modify the RNA-RBP networks. Proper regulation and management of RNA characteristics are fundamental to cellular and organismal homeostasis, as well as paramount to health. Identification of multiple single nucleotide polymorphisms (SNPs) within loci of fat mass- and obesity-associated protein (FTO) gene, an RNA demethylase, through genome-wide association studies (GWAS) of T2D, and functional assessments of FTO in mice, support the concept that disruption in RNA modifications leads to the development of human diseases including obesity and metabolic disorder. In obesity, dynamic alterations in modification and localization of RNAs appear to modulate the RNA-RBP networks and activate proinflammatory RBPs, such as double-stranded RNA (dsRNA)-dependent protein kinase (PKR), Toll-like receptor (TLR) 3 and TLR7, and RNA silencing machinery. These changes induce aberrant inflammation and the development of metabolic diseases. This review will describe the current understanding of the underlying causes of these common and altered characteristics of RNA-RBP networks which will pave the way for developing novel approaches to tackle the pandemic issue of obesity.
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Affiliation(s)
- Esam S B Salem
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Andrew D Vonberg
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Vishnupriya J Borra
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Rupinder K Gill
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Takahisa Nakamura
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.,Department of Metabolic Bioregulation, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
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12
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Hood IV, Gordon JM, Bou-Nader C, Henderson FE, Bahmanjah S, Zhang J. Crystal structure of an adenovirus virus-associated RNA. Nat Commun 2019; 10:2871. [PMID: 31253805 PMCID: PMC6599070 DOI: 10.1038/s41467-019-10752-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/27/2019] [Indexed: 12/20/2022] Open
Abstract
Adenovirus Virus-Associated (VA) RNAs are the first discovered viral noncoding RNAs. By mimicking double-stranded RNAs (dsRNAs), the exceptionally abundant, multifunctional VA RNAs sabotage host machineries that sense, transport, process, or edit dsRNAs. How VA-I suppresses PKR activation despite its strong dsRNA character, and inhibits the crucial antiviral kinase to promote viral translation, remains largely unknown. Here, we report a 2.7 Å crystal structure of VA-I RNA. The acutely bent VA-I features an unusually structured apical loop, a wobble-enriched, coaxially stacked apical and tetra-stems necessary and sufficient for PKR inhibition, and a central domain pseudoknot that resembles codon-anticodon interactions and prevents PKR activation by VA-I. These global and local structural features collectively define VA-I as an archetypal PKR inhibitor made of RNA. The study provides molecular insights into how viruses circumnavigate cellular rules of self vs non-self RNAs to not only escape, but further compromise host innate immunity.
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Affiliation(s)
- Iris V Hood
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Jackson M Gordon
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Frances E Henderson
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Soheila Bahmanjah
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA.
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Klepsch O, Namer LS, Köhler N, Kaempfer R, Dittrich A, Schaper F. Intragenic regulation of SOCS3 isoforms. Cell Commun Signal 2019; 17:70. [PMID: 31238931 PMCID: PMC6593527 DOI: 10.1186/s12964-019-0379-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 05/01/2019] [Indexed: 11/13/2022] Open
Abstract
Background Inflammatory reactions are commonly affected by stress responses. Interleukin-6 signalling is part of the inflammatory response and is stringently regulated by the feedback inhibitor SOCS3 expressed in a short and long isoform. Here, we studied the inhibitory potential of the two SOCS3 isoforms. Furthermore, we analysed the regulation of SOCS3 isoform expression and the role of PKR stress kinase signalling in SOCS3 protein expression. Methods We performed Western blotting, reporter assays, genetic analyses and manipulations for studying SOCS3 isoform expression and activation of signalling components involved in interleukin-6-induced and PKR-dependent signalling. Results Interleukin-6-induced endogenous expression of both SOCS3 isoforms was found in distinct cell types. Forced expression of either the long or short SOCS3 isoform demonstrated equal inhibitory activity of each isoform and confirmed longer half-life of the short isoform. Study of intragenic regulation of SOCS3 isoform expression revealed that (i) the 5′-UTR of SOCS3 mRNA restrains specifically expression of the long SOCS3 isoform, (ii) expression of the long isoform restrains expression of the short isoform, and (iii) signalling through the stress kinase PKR does not impact on SOCS3 isoform ratio. Conclusions Both SOCS3 isoforms show a similar potential for inhibiting interleukin-6 signalling but differ in their half-lives. Relative expression of the isoforms depends on intragenic elements yet is independent of PKR signalling. Graphic abstract ![]()
Electronic supplementary material The online version of this article (10.1186/s12964-019-0379-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Oliver Klepsch
- Department of Systems Biology, Institute of Biology, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Lise Sarah Namer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Nadine Köhler
- Department of Systems Biology, Institute of Biology, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Anna Dittrich
- Department of Systems Biology, Institute of Biology, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany.
| | - Fred Schaper
- Department of Systems Biology, Institute of Biology, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany.
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Kaempfer R, Ilan L, Cohen-Chalamish S, Turgeman O, Namer LS, Osman F. Control of mRNA Splicing by Intragenic RNA Activators of Stress Signaling: Potential Implications for Human Disease. Front Genet 2019; 10:464. [PMID: 31139209 PMCID: PMC6527590 DOI: 10.3389/fgene.2019.00464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/30/2019] [Indexed: 11/13/2022] Open
Abstract
A critical step in the cellular stress response is transient activation of the RNA-dependent protein kinase PKR by double-helical RNA, resulting in down-regulation of protein synthesis through phosphorylation of the α chain of translation initiation factor eIF2, a major PKR substrate. However, intragenic elements of 100–200 nucleotides in length within primary transcripts of cellular genes, exemplified by the tumor necrosis factor (TNF)-α gene and fetal and adult globin genes, are capable of forming RNA structures that potently activate PKR and thereby strongly enhance mRNA splicing efficiency. By inducing nuclear eIF2α phosphorylation, these PKR activator elements enable highly efficient early spliceosome assembly yet do not impair translation of the mature spliced mRNA. The TNF-α RNA activator of PKR folds into a compact pseudoknot that is highly conserved within the phylogeny. Upon excision of β-globin first intron, the RNA activator of PKR, located in exon 1, is silenced through strand displacement by a short sequence within exon 2, restricting thereby the ability to activate PKR to the splicing process without impeding subsequent synthesis of β-globin essential for survival. This activator/silencer mechanism likewise controls splicing of α-globin pre-mRNA, but the exonic locations of PKR activator and silencer sequences are reversed, demonstrating evolutionary flexibility. Impaired splicing efficiency may underlie numerous human β-thalassemia mutations that map to the β-globin RNA activator of PKR or its silencer. Even where such mutations change the encoded amino acid sequence during subsequent translation, they carry the potential of first impairing PKR-dependent mRNA splicing or shutoff of PKR activation needed for optimal translation.
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Affiliation(s)
- Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Lena Ilan
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Smadar Cohen-Chalamish
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Orli Turgeman
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Lise Sarah Namer
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Farhat Osman
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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Bou-Nader C, Gordon JM, Henderson FE, Zhang J. The search for a PKR code-differential regulation of protein kinase R activity by diverse RNA and protein regulators. RNA (NEW YORK, N.Y.) 2019; 25:539-556. [PMID: 30770398 PMCID: PMC6467004 DOI: 10.1261/rna.070169.118] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The interferon-inducible protein kinase R (PKR) is a key component of host innate immunity that restricts viral replication and propagation. As one of the four eIF2α kinases that sense diverse stresses and direct the integrated stress response (ISR) crucial for cell survival and proliferation, PKR's versatile roles extend well beyond antiviral defense. Targeted by numerous host and viral regulators made of RNA and proteins, PKR is subject to multiple layers of endogenous control and external manipulation, driving its rapid evolution. These versatile regulators include not only the canonical double-stranded RNA (dsRNA) that activates the kinase activity of PKR, but also highly structured viral, host, and artificial RNAs that exert a full spectrum of effects. In this review, we discuss our deepening understanding of the allosteric mechanism that connects the regulatory and effector domains of PKR, with an emphasis on diverse structured RNA regulators in comparison to their protein counterparts. Through this analysis, we conclude that much of the mechanistic details that underlie this RNA-regulated kinase await structural and functional elucidation, upon which we can then describe a "PKR code," a set of structural and chemical features of RNA that are both descriptive and predictive for their effects on PKR.
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Affiliation(s)
- Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jackson M Gordon
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Frances E Henderson
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
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Kaempfer R, Namer LS, Osman F, Ilan L. Control of mRNA splicing by noncoding intragenic RNA elements that evoke a cellular stress response. Int J Biochem Cell Biol 2018; 105:20-23. [PMID: 30282053 DOI: 10.1016/j.biocel.2018.09.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/25/2018] [Accepted: 09/27/2018] [Indexed: 11/15/2022]
Abstract
Once activated by double-helical RNA, mammalian RNA-dependent stress protein kinase, PKR, phosphorylates its substrate, translation initiation factor eIF2α, to inhibit translation. eIF2α phosphorylation is critical for mounting a cellular stress response. We describe short, 100-200 nucleotide elements within cellular genes that, once transcribed, form RNA structures that potently activate PKR in the vicinity of the RNA and thereby tightly regulate gene expression in cis. Intragenic RNA activators of PKR can (a) attenuate translation of the encoded mRNA by activating PKR and inducing eIF2α phosphorylation, exemplified by the IFN-γ gene, or (b) greatly enhance mRNA splicing efficiency by activating PKR and inducing nuclear eIF2α phosphorylation, thus enabling efficient early spliceosome assembly, exemplified by the adult and fetal globin genes and the TNF-α gene that activates PKR through an RNA pseudoknot conserved from fish to humans. These opposite outcomes considerably extend the potential scope of gene regulation by these novel RNA elements.
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Affiliation(s)
- Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The Hebrew University, Jerusalem, Israel.
| | - Lise Sarah Namer
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - Farhat Osman
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - Lena Ilan
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
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Leppek K, Das R, Barna M. Functional 5' UTR mRNA structures in eukaryotic translation regulation and how to find them. Nat Rev Mol Cell Biol 2018; 19:158-174. [PMID: 29165424 PMCID: PMC5820134 DOI: 10.1038/nrm.2017.103] [Citation(s) in RCA: 490] [Impact Index Per Article: 81.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
RNA molecules can fold into intricate shapes that can provide an additional layer of control of gene expression beyond that of their sequence. In this Review, we discuss the current mechanistic understanding of structures in 5' untranslated regions (UTRs) of eukaryotic mRNAs and the emerging methodologies used to explore them. These structures may regulate cap-dependent translation initiation through helicase-mediated remodelling of RNA structures and higher-order RNA interactions, as well as cap-independent translation initiation through internal ribosome entry sites (IRESs), mRNA modifications and other specialized translation pathways. We discuss known 5' UTR RNA structures and how new structure probing technologies coupled with prospective validation, particularly compensatory mutagenesis, are likely to identify classes of structured RNA elements that shape post-transcriptional control of gene expression and the development of multicellular organisms.
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Affiliation(s)
- Kathrin Leppek
- Department of Developmental Biology, Stanford University, Stanford, California 94305, USA
- Department of Genetics, Stanford University, Stanford, California 94305, USA
| | - Rhiju Das
- Departments of Biochemistry and Physics, Stanford University, Stanford, California 94305, USA
| | - Maria Barna
- Department of Developmental Biology, Stanford University, Stanford, California 94305, USA
- Department of Genetics, Stanford University, Stanford, California 94305, USA
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CUG initiation and frameshifting enable production of dipeptide repeat proteins from ALS/FTD C9ORF72 transcripts. Nat Commun 2018; 9:152. [PMID: 29323119 PMCID: PMC5764992 DOI: 10.1038/s41467-017-02643-5] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/14/2017] [Indexed: 12/12/2022] Open
Abstract
Expansion of G4C2 repeats in the C9ORF72 gene is the most prevalent inherited form of amyotrophic lateral sclerosis and frontotemporal dementia. Expanded transcripts undergo repeat-associated non-AUG (RAN) translation producing dipeptide repeat proteins from all reading frames. We determined cis-factors and trans-factors influencing translation of the human C9ORF72 transcripts. G4C2 translation operates through a 5′–3′ cap-dependent scanning mechanism, requiring a CUG codon located upstream of the repeats and an initiator Met-tRNAMeti. Production of poly-GA, poly-GP, and poly-GR proteins from the three frames is influenced by mutation of the same CUG start codon supporting a frameshifting mechanism. RAN translation is also regulated by an upstream open reading frame (uORF) present in mis-spliced C9ORF72 transcripts. Inhibitors of the pre-initiation ribosomal complex and RNA antisense oligonucleotides selectively targeting the 5′-flanking G4C2 sequence block ribosomal scanning and prevent translation. Finally, we identified an unexpected affinity of expanded transcripts for the ribosomal subunits independently from translation. Repeat-associated non-AUG (RAN) translation contributes to the pathogenic mechanism of several microsatellite expansion diseases. Here the authors delineate the different steps involved in recruiting the ribosome to initiate G4C2 RAN translation to produce poly-Glycine Alanine, poly-Glycine Proline, and poly-Glycine Arginine repeats.
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Wang L, Wu Z, Huang Q, Huang K, Qi G, Wu C, Mao H, Xu X, Wang H, Hu C. Grass carp (Ctenopharyngodon idella) STAT3 regulates the eIF2α phosphorylation through interaction with PKR. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 78:26-34. [PMID: 28916266 DOI: 10.1016/j.dci.2017.08.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/25/2017] [Accepted: 08/27/2017] [Indexed: 06/07/2023]
Abstract
In mammals, STAT3 (Signal transducer and activator of transcription 3) plays an important role in growth, multiplication, differentiation and participates in inflammation, tumorigenesis, metabolic disorders and immune response. STAT3 is a protein that shuttles between the nucleus and cytoplasm. Compared to the STAT3 in cell nucleus, we did not know the function of STAT3 in cytoplasm for a long time. Some recent studies have shown that cytoplasmic STAT3 regulates autophagy through the interaction with the double-stranded RNA-activated protein kinase (PKR), which plays an important role in cellular antiviral response. Fish is a good target for developmental and comparative immunology. In the present study, we found that the expression of grass carp (Ctenopharyngodon idella) STAT3 (CiSTAT3) was ubiquitous and significantly up-regulated under the stimulation of poly I:C. To explore the potential function of fish cytoplasmic STAT3 in the antiviral signaling pathways, in this paper we analyzed the relationship between cytoplasmic CiSTAT3 and CiPKR. We demonstrated that the CiSTAT3 can combine with CiPKR in vivo and in vitro. The SH2 domain of CiSTAT3 and the C-terminus of CiPKR play an important role in this process. Moreover, the dimer of CiSTAT3 and CiPKR was formed under normal circumstances, however, it was dissociated under the induction of poly I:C. So, we guessed the binding of CiSTAT3 and CiPKR may regulate cell viability. It has also been shown that overexpression of CiSTAT3 in CIK cells can significantly reduce the level of p-eIF2α. On the contrary, the siRNA-mediated knockdown of CiSTAT3 and Stattic induction in CIK cells can up-regulate the p-eIF2α level. To further understand the relationship between CiSTAT3 and p-eIF2α level, we carried out the CiPKR-knockdown experiment. The result indicated that CiSTAT3 regulated the level of p-eIF2α through binding to CiPKR. In addition, overexpression of CiSTAT3 in CIK cells was able to improve the cell viability. These results above unraveled the molecular mechanism of fish cytoplasmic STAT3 regulating the eIF2α phosphorylation and cell viability. Therefore, the function of fish cytoplasmic STAT3 is similar to those of mammals.
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Affiliation(s)
- Liqiang Wang
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Zhen Wu
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Qingli Huang
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Keyi Huang
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Guoqin Qi
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Chuxin Wu
- Yuzhang Normal University, Nanchang 330031, China
| | - Huiling Mao
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Xiaowen Xu
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Haizhou Wang
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China
| | - Chengyu Hu
- College of Life Science, Poyang Lake Key Laboratory of Environment and Resource Utilization (Nanchang University) Ministry of Education, Nanchang 330031, China.
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