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Peng K, Wang N, Liu Q, Wang L, Duan X, Xie G, Li J, Ding D. Identification of disulfidptosis-related subtypes and development of a prognosis model based on stacking framework in renal clear cell carcinoma. J Cancer Res Clin Oncol 2023; 149:13793-13810. [PMID: 37530800 DOI: 10.1007/s00432-023-05201-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 07/22/2023] [Indexed: 08/03/2023]
Abstract
BACKGROUND Clear cell renal cell carcinoma (ccRCC) is a common malignant tumor with an unsatisfactory prognosis. This study aims to identify the expression patterns of disulfidptosis-related genes (DRGs), develop a prognostic model, and predict immunological profiles. METHODS First, we identified differentially expressed DRGs in TCGA-KIRC cohort and analyzed their mutational profiles, methylation levels, and interaction networks. Subsequently, we identified disulfidptosis-associated molecular subtypes and investigated their prognostic and immunological characteristics. Simultaneously, a disulfidptosis-related prognostic signature (DRPS) was developed using a two-stage stacking framework consisting of 5 machine learning models. The effect of DRPS on immune cell infiltration levels was explored using seven different algorithms, and the status and function of T cells for distinct risk-score groups were evaluated based on T cell exhaustion and dysfunction scores. Additionally, the study also examined differences in clinical characteristics and therapy efficacy between high- and low-risk groups. RESULTS We found two disulfidptosis-associated clusters, one of which had a poor prognosis and was linked to high immune cell infiltration but impaired T cell function. DRPS showed excellent predictive performance in all four cohorts and could accurately identified disulfidptosis-related molecular subtypes. The DRPS-based risk score was positively associated with poor prognosis, malignant pathological features, high immune cell infiltration levels, and T cell exhaustion or dysfunction, and better respond to immunotherapy and targeted therapy. Additionally, we have identified a close association between ISG20 and disulfidptosis as well as tumor immunity. CONCLUSION Our study identified distinct disulfidptosis-related subtypes in ccRCC patients, and constructed the highly accurate and robust DRPS based on an ensemble learning framework, which has critical reference value in clinical decision-making and individualized treatment. And this work also revealed ISG20 exhibits promising potential as a therapeutic target for ccRCC.
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Affiliation(s)
- Kun Peng
- Department of Urology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Ning Wang
- Department of Urology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Qingyuan Liu
- Department of Urology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Lingdian Wang
- Department of Urology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Xiaoyu Duan
- Department of Urology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Guochong Xie
- Department of Urology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Jixi Li
- Department of Urology, People's Hospital of Henan University, Henan Provincial People's Hospital, Zhengzhou, 450003, China
| | - Degang Ding
- Department of Urology, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
- Department of Urology, People's Hospital of Henan University, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
- Institute of Urology, Henan Provincial People's Hospital, Zhengzhou, China.
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2
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Jia M, Li L, Chen R, Du J, Qiao Z, Zhou D, Liu M, Wang X, Wu J, Xie Y, Sun Y, Zhang Y, Wang Z, Zhang T, Hu H, Sun J, Tang W, Yi F. Targeting RNA oxidation by ISG20-mediated degradation is a potential therapeutic strategy for acute kidney injury. Mol Ther 2023; 31:3034-3051. [PMID: 37452495 PMCID: PMC10556188 DOI: 10.1016/j.ymthe.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/20/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023] Open
Abstract
Oxidative stress plays a central role in the pathophysiology of acute kidney injury (AKI). Although RNA is one of the most vulnerable cell components to oxidative damage, it is unclear whether RNA oxidation is involved in the pathogenesis of AKI. In this study, we found that the level of RNA oxidation was significantly enhanced in kidneys of patients with acute tubular necrosis (ATN) and in the renal tubular epithelial cells (TECs) of mice with AKI, and oxidized RNA overload resulted in TEC injury. We further identified interferon-stimulated gene 20 (ISG20) as a novel regulator of RNA oxidation in AKI. Tubule-specific deficiency of ISG20 significantly aggravated renal injury and RNA oxidation in the ischemia/reperfusion-induced AKI mouse model and ISG20 restricted RNA oxidation in an exoribonuclease activity-dependent manner. Importantly, overexpression of ISG20 protected against oxidized RNA overproduction and renal ischemia/reperfusion injury in mice and ameliorated subsequent protein aggresome accumulation, endoplasmic reticulum stress, and unfolded protein response. Thus, our findings provide direct evidence that RNA oxidation contributes to the pathogenesis of AKI and that ISG20 importantly participates in the degradation of oxidized RNA, suggesting that targeting ISG20-handled RNA oxidation may be an innovative therapeutic strategy for AKI.
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Affiliation(s)
- Meng Jia
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Liang Li
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Ruiqi Chen
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Junyao Du
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Zhe Qiao
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Di Zhou
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Min Liu
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Xiaojie Wang
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Jichao Wu
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Yusheng Xie
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Yu Sun
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Yan Zhang
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Ziying Wang
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Tao Zhang
- Department of Biostatistics, School of Public Health, Shandong University, Jinan 250012, China
| | - Huili Hu
- Department of Systems Biomedicine and Research Center of Stem Cell and Regenerative Medicine, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Jinpeng Sun
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China
| | - Wei Tang
- Department of Pathogenic Biology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China.
| | - Fan Yi
- Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan 250012, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Cheeloo College of Medicine, Shandong University, Jinan 250012, China.
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3
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Kazzi PE, Rabah N, Chamontin C, Poulain L, Ferron F, Debart F, Canard B, Missé D, Coutard B, Nisole S, Decroly E. Internal RNA 2′O-methylation in the HIV-1 genome counteracts ISG20 nuclease-mediated antiviral effect. Nucleic Acids Res 2022; 51:2501-2515. [PMID: 36354007 PMCID: PMC10085690 DOI: 10.1093/nar/gkac996] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 09/16/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
Abstract
RNA 2′O-methylation is a ‘self’ epitranscriptomic modification allowing discrimination between host and pathogen. Indeed, human immunodeficiency virus 1 (HIV-1) induces 2′O-methylation of its genome by recruiting the cellular FTSJ3 methyltransferase, thereby impairing detection by RIG-like receptors. Here, we show that RNA 2′O-methylations interfere with the antiviral activity of interferon-stimulated gene 20-kDa protein (ISG20). Biochemical experiments showed that ISG20-mediated degradation of 2′O-methylated RNA pauses two nucleotides upstream of and at the methylated residue. Structure-function analysis indicated that this inhibition is due to steric clash between ISG20 R53 and D90 residues and the 2′O-methylated nucleotide. We confirmed that hypomethylated HIV-1 genomes produced in FTSJ3-KO cells were more prone to in vitro degradation by ISG20 than those produced in cells expressing FTSJ3. Finally, we found that reverse-transcription of hypomethylated HIV-1 was impaired in T cells by interferon-induced ISG20, demonstrating the direct antagonist effect of 2′O-methylation on ISG20-mediated antiviral activity.
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Affiliation(s)
- Priscila El Kazzi
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
| | - Nadia Rabah
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
- Université de Toulon , 83130 La Garde , France
| | - Célia Chamontin
- IRIM, CNRS UMR9004, Université de Montpellier , Montpellier , France
| | - Lina Poulain
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
| | - François Ferron
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
- European Virus Bioinformatics Center , Leutragraben 1, 07743 Jena , Germany
| | - Françoise Debart
- IBMM, UMR 5247 CNRS, Université de Montpellier , ENSCM, Montpellier , France
| | - Bruno Canard
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
| | - Dorothée Missé
- MIVEGEC, Univ. Montpellier, CNRS , IRD, Montpellier, France
| | - Bruno Coutard
- Unité des Virus Émergents (UVE: Aix-Marseille Univ-IRD 190-Inserm 1207) , Marseille , France
| | - Sébastien Nisole
- IRIM, CNRS UMR9004, Université de Montpellier , Montpellier , France
| | - Etienne Decroly
- AFMB, CNRS, Aix-Marseille University , UMR 7257, Case 925, 163 Avenue de Luminy , 13288 Marseille Cedex 09, France
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Deymier S, Louvat C, Fiorini F, Cimarelli A. ISG20: an enigmatic antiviral RNase targeting multiple viruses. FEBS Open Bio 2022; 12:1096-1111. [PMID: 35174977 PMCID: PMC9157404 DOI: 10.1002/2211-5463.13382] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/31/2022] [Accepted: 02/15/2022] [Indexed: 11/25/2022] Open
Abstract
Interferon‐stimulated gene 20 kDa protein (ISG20) is a relatively understudied antiviral protein capable of inhibiting a broad spectrum of viruses. ISG20 exhibits strong RNase properties, and it belongs to the large family of DEDD exonucleases, present in both prokaryotes and eukaryotes. ISG20 was initially characterized as having strong RNase activity in vitro, suggesting that its inhibitory effects are mediated via direct degradation of viral RNAs. This mechanism of action has since been further elucidated and additional antiviral activities of ISG20 highlighted, including direct degradation of deaminated viral DNA and translational inhibition of viral RNA and nonself RNAs. This review focuses on the current understanding of the main molecular mechanisms of viral inhibition by ISG20 and discusses the latest developments on the features that govern specificity or resistance to its action.
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Affiliation(s)
- Séverine Deymier
- Centre International de Recherche en Infectiologie (CIRI), Université de Lyon Inserm, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Nationale Supérieur de Lyon, U1111, Lyon, France
| | | | | | - Andrea Cimarelli
- Centre International de Recherche en Infectiologie (CIRI), Université de Lyon Inserm, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Nationale Supérieur de Lyon, U1111, Lyon, France
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5
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Luo H, Zhang Y, Hu N, He Y, He C. Systematic Construction and Validation of an RNA-Binding Protein-Associated Prognostic Model for Acute Myeloid Leukemia. Front Genet 2021; 12:715840. [PMID: 34630514 PMCID: PMC8498117 DOI: 10.3389/fgene.2021.715840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/26/2021] [Indexed: 12/13/2022] Open
Abstract
Background: The abnormal expression of RNA-binding proteins (RBPs) in various malignant tumors is closely related to the occurrence and development of tumors. However, the role of RBPs in acute myeloid leukemia (AML) is unclear. Methods: We downloaded harmonized RNA-seq count data and clinical data for AML from UCSC Xena, including The Cancer Genome Atlas (TCGA), The Genotype-Tissue Expression (GTEx), and Therapeutically Applicable Research to Generate Effective Treatments (TARGET) cohorts. R package edgeR was used for differential expression analysis of 337 whole-blood data and 173 AML data. The prognostic value of these RBPs was systematically investigated by using univariate Cox regression analysis, least absolute shrinkage and selection operator (LASSO)-Cox regression analysis, and multivariate Cox regression analysis. C-index and calibration diagram were used to judge the accuracy of the model, and decision curve analysis (DCA) was used to judge the net benefit. The biological pathways involved were revealed by gene set enrichment analysis (GSEA). The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and the protein-protein interaction (PPI) network performed lateral verification on the selected gene set and LASSO results. Results: A prognostic model of 12-RBP signature was established. In addition, the net benefit and prediction accuracy of the prognostic model and the mixed model based on it were significantly higher than that of cytogenetics. It is verified in the TARGET cohort and shows good prediction effect. Both the selection of our gene set and the LASSO results have high credibility. Most of these pathways are involved in the development of the disease, and they also accumulate in leukemia and RNA-related pathways. Conclusion: The prognosis model of the 12-RBP signature found in this study is an optimized biomarker that can effectively stratify the risk of AML patients. Nomogram based on this prognostic model is a reliable method to predict the median survival time of patients. This study expands our current understanding of the role of RBPs in the occurrence of AML and may lay the foundation for future treatment of the disease.
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Affiliation(s)
| | | | - Nan Hu
- Southwest Medical University, Luzhou, China
| | - Yancheng He
- Jiangyang City Construction College, Luzhou, China
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6
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Stadler D, Kächele M, Jones AN, Hess J, Urban C, Schneider J, Xia Y, Oswald A, Nebioglu F, Bester R, Lasitschka F, Ringelhan M, Ko C, Chou W, Geerlof A, van de Klundert MA, Wettengel JM, Schirmacher P, Heikenwälder M, Schreiner S, Bartenschlager R, Pichlmair A, Sattler M, Unger K, Protzer U. Interferon-induced degradation of the persistent hepatitis B virus cccDNA form depends on ISG20. EMBO Rep 2021; 22:e49568. [PMID: 33969602 PMCID: PMC8183418 DOI: 10.15252/embr.201949568] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/18/2021] [Accepted: 03/23/2021] [Indexed: 12/16/2022] Open
Abstract
Hepatitis B virus (HBV) persists by depositing a covalently closed circular DNA (cccDNA) in the nucleus of infected cells that cannot be targeted by available antivirals. Interferons can diminish HBV cccDNA via APOBEC3-mediated deamination. Here, we show that overexpression of APOBEC3A alone is not sufficient to reduce HBV cccDNA that requires additional treatment of cells with interferon indicating involvement of an interferon-stimulated gene (ISG) in cccDNA degradation. Transcriptome analyses identify ISG20 as the only type I and II interferon-induced, nuclear protein with annotated nuclease activity. ISG20 localizes to nucleoli of interferon-stimulated hepatocytes and is enriched on deoxyuridine-containing single-stranded DNA that mimics transcriptionally active, APOBEC3A-deaminated HBV DNA. ISG20 expression is detected in human livers in acute, self-limiting but not in chronic hepatitis B. ISG20 depletion mitigates the interferon-induced loss of cccDNA, and co-expression with APOBEC3A is sufficient to diminish cccDNA. In conclusion, non-cytolytic HBV cccDNA decline requires the concerted action of a deaminase and a nuclease. Our findings highlight that ISGs may cooperate in their antiviral activity that may be explored for therapeutic targeting.
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7
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Chen X, Sun D, Dong S, Zhai H, Kong N, Zheng H, Tong W, Li G, Shan T, Tong G. Host Interferon-Stimulated Gene 20 Inhibits Pseudorabies Virus Proliferation. Virol Sin 2021; 36:1027-1035. [PMID: 33830434 DOI: 10.1007/s12250-021-00380-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 02/23/2021] [Indexed: 12/30/2022] Open
Abstract
Host interferon-stimulated gene 20 (ISG20) exerts antiviral effects on viruses by degrading viral RNA or by enhancing IFN signaling. Here, we examined the role of ISG20 during pseudorabies virus (PRV) proliferation. We found that ISG20 modulates PRV replication by enhancing IFN signaling. Further, ISG20 expression was upregulated following PRV infection and poly(I:C) treatment. Ectopic expression of ISG20 inhibited PRV proliferation in PK15 cells, whereas knockdown of ISG20 promoted PRV proliferation. In addition, ISG20 expression upregulated IFN-β expression and enhanced IFN downstream signaling during PRV infection. Notably, PRV UL24 suppressed the transcription of ISG20, thus antagonizing its antiviral effect. Further domain mapping analysis showed that the N terminus (amino acids 1-90) of UL24 was responsible for the inhibition of ISG20 transcription. Collectively, these findings characterize the role of ISG20 in suppressing PRV replication and increase the understanding of host-PRV interplay.
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Affiliation(s)
- Xiaoyong Chen
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Dage Sun
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Sujie Dong
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Huanjie Zhai
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Ning Kong
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, China
| | - Hao Zheng
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, China
| | - Wu Tong
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, China
| | - Guoxin Li
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, China
| | - Tongling Shan
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. .,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, China.
| | - Guangzhi Tong
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China. .,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, China.
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8
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Kawamoto T, Yoshimoto R, Taniguchi I, Kitabatake M, Ohno M. ISG20 and nuclear exosome promote destabilization of nascent transcripts for spliceosomal U snRNAs and U1 variants. Genes Cells 2020; 26:18-30. [PMID: 33147372 DOI: 10.1111/gtc.12817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/29/2020] [Accepted: 10/29/2020] [Indexed: 11/28/2022]
Abstract
Primary RNA transcripts are processed in a plethora of ways to become mature functional forms. In one example, human spliceosomal U snRNAs are matured at their 3'-end by an exonuclease termed TOE1. This process is important because mutations in TOE1 gene can cause a human genetic disease, pontocerebellar hypoplasia (PCH). Nevertheless, TOE1 may not be the only maturation exonuclease for U snRNAs in the cell. Here, we biochemically identify two exonucleolytic factors, Interferon-stimulated gene 20-kDa protein (ISG20) and the nuclear exosome as such candidates, using a newly developed in vitro system that recapitulates 3'-end maturation of U1 snRNA. However, extensive 3'-end sequencing of endogenous U1 snRNA of the knockdown (KD) cells revealed that these factors are not the maturation factors per se. Instead, the nascent transcripts of the spliceosomal U snRNAs as well as of unstable U1 variants were found to increase in quantity upon KD of the factors. These results indicated that ISG20 and the nuclear exosome promote the degradation of nascent spliceosomal U snRNAs and U1 variants, and therefore implied their role in the quality control of newly synthesized U snRNAs.
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Affiliation(s)
- Takahito Kawamoto
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Rei Yoshimoto
- Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Hirakata, Japan
| | - Ichiro Taniguchi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Makoto Kitabatake
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Mutsuhito Ohno
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
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9
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Park YK, Lee SY, Lee AR, Kim K, Kim K, Kim K, Choi B. Antiviral activity of interferon-stimulated gene 20, as a putative repressor binding to hepatitis B virus enhancer II and core promoter. J Gastroenterol Hepatol 2020; 35:1426-1436. [PMID: 31951295 PMCID: PMC7497004 DOI: 10.1111/jgh.14986] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 12/30/2019] [Accepted: 01/13/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIM Interferon-stimulated gene 20 (ISG20) is an interferon-inducible exonuclease that inhibits the replication of several RNA viruses. In patients with chronic hepatitis B, ISG20 expression is related to the interferon-α treatment response. However, the molecular mechanism of ISG20-mediated anti-hepatitis B virus (HBV) activity is unclear. METHODS We have investigated the effect of ISG20 on antiviral activity to address that. The life cycle of HBV was analyzed by the ectopic expression of ISG20 in HepG2 and HepG2-NTCP cells. Finally, to provide physiological relevance of our study, the expression of ISG20 from chronic hepatitis B patients was examined. RESULTS Interferon-stimulated gene 20 was mainly induced by interferon-β and dramatically inhibited HBV replication. In addition, ISG20 decreased HBV gene expression and transcription. Although ISG20 inhibited HBV replication by reducing viral enhancer activity, the expression of transcription factors that bind the HBV enhancer was not affected. Particularly, ISG20 suppressed HBV enhancer activity by binding to the enhancer II and core promoter (EnhII/Cp) region. CONCLUSION Our findings suggest that ISG20 exerts the anti-HBV activity by acting as a putative repressor binding to the HBV EnhII/Cp region.
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Affiliation(s)
- Yong Kwang Park
- Division of Viral Disease Research, Center for Infectious Disease ResearchKorea National Institute of HealthCheongju‐siChungbukKorea
| | - Sun Young Lee
- Division of Viral Disease Research, Center for Infectious Disease ResearchKorea National Institute of HealthCheongju‐siChungbukKorea
| | - Ah Ram Lee
- Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of MedicineKonkuk UniversitySeoulKorea
| | - Kyung‐Chang Kim
- Division of Viral Disease Research, Center for Infectious Disease ResearchKorea National Institute of HealthCheongju‐siChungbukKorea
| | - Kisoon Kim
- Division of Viral Disease Research, Center for Infectious Disease ResearchKorea National Institute of HealthCheongju‐siChungbukKorea
| | - Kyun‐Hwan Kim
- Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of MedicineKonkuk UniversitySeoulKorea
| | - Byeong‐Sun Choi
- Division of Viral Disease Research, Center for Infectious Disease ResearchKorea National Institute of HealthCheongju‐siChungbukKorea
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10
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Wu N, Nguyen XN, Wang L, Appourchaux R, Zhang C, Panthu B, Gruffat H, Journo C, Alais S, Qin J, Zhang N, Tartour K, Catez F, Mahieux R, Ohlmann T, Liu M, Du B, Cimarelli A. The interferon stimulated gene 20 protein (ISG20) is an innate defense antiviral factor that discriminates self versus non-self translation. PLoS Pathog 2019; 15:e1008093. [PMID: 31600344 PMCID: PMC6805002 DOI: 10.1371/journal.ppat.1008093] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/22/2019] [Accepted: 09/18/2019] [Indexed: 01/29/2023] Open
Abstract
ISG20 is a broad spectrum antiviral protein thought to directly degrade viral RNA. However, this mechanism of inhibition remains controversial. Using the Vesicular Stomatitis Virus (VSV) as a model RNA virus, we show here that ISG20 interferes with viral replication by decreasing protein synthesis in the absence of RNA degradation. Importantly, we demonstrate that ISG20 exerts a translational control over a large panel of non-self RNA substrates including those originating from transfected DNA, while sparing endogenous transcripts. This activity correlates with the protein's ability to localize in cytoplasmic processing bodies. Finally, these functions are conserved in the ISG20 murine ortholog, whose genetic ablation results in mice with increased susceptibility to viral infection. Overall, our results posit ISG20 as an important defense factor able to discriminate the self/non-self origins of the RNA through translation modulation.
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Affiliation(s)
- Nannan Wu
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
- Shanghai Emerging and Reemerging Infectious Disease Institute, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Xuan-Nhi Nguyen
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Li Wang
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Romain Appourchaux
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Chengfei Zhang
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Baptiste Panthu
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Henri Gruffat
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Chloé Journo
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Sandrine Alais
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Juliang Qin
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Na Zhang
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Kevin Tartour
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Frédéric Catez
- Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Lyon, France
| | - Renaud Mahieux
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Theophile Ohlmann
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Mingyao Liu
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Bing Du
- Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
- * E-mail: (BD); (AC)
| | - Andrea Cimarelli
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
- * E-mail: (BD); (AC)
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11
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Gao M, Lin Y, Liu X, Li Y, Zhang C, Wang Z, Wang Z, Wang Y, Guo Z. ISG20 promotes local tumor immunity and contributes to poor survival in human glioma. Oncoimmunology 2018; 8:e1534038. [PMID: 30713788 PMCID: PMC6343791 DOI: 10.1080/2162402x.2018.1534038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 10/01/2018] [Accepted: 10/02/2018] [Indexed: 12/20/2022] Open
Abstract
Recent evidence has confirmed that a mutation of the isocitrate dehydrogenase (IDH) gene occurs early in gliomagenesis and contributes to suppressed immunity. The present study aimed to determine the candidate genes associated with IDH mutation status that could serve as biomarkers of immune suppression for improved prognosis prediction. Clinical information and RNA-seq gene expression data were collected for 932 glioma samples from the CGGA and TCGA databases, and differentially expressed genes in both lower-grade glioma (LGG) and glioblastoma (GBM) samples were identified according to IDH mutation status. Only one gene, interferon-stimulated exonuclease gene 20 (ISG20), with reduced expression in IDH mutant tumors, demonstrated significant prognostic value. ISG20 expression level significantly increased with increasing tumor grade, and its high expression was associated with a poor clinical outcome. Moreover, increased ISG20 expression was associated with increased infiltration of monocyte-derived macrophages and neutrophils, and suppressed adaptive immune response. ISG20 expression was also positively correlated with PD-1, PD-L1, and CTLA4 expression, along with the levels of several chemokines. We conclude that ISG20 is a useful biomarker to identify IDH-mediated immune processes in glioma and may serve as a potential therapeutic target.
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Affiliation(s)
- Mengqi Gao
- Department of Neurosurgery, the First Hospital of China Medical University, Shenyang, China
| | - Yi Lin
- Department of Neurosurgery, the First Hospital of China Medical University, Shenyang, China
| | - Xing Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Genome Atlas network, Beijing, China
| | - Yiming Li
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Genome Atlas network, Beijing, China
| | - Chuanbao Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Genome Atlas network, Beijing, China
| | - Zheng Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Genome Atlas network, Beijing, China
| | - Zhiliang Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Chinese Glioma Genome Atlas network, Beijing, China
| | - Yulin Wang
- Department of Neurosurgery, the First Hospital of China Medical University, Shenyang, China
| | - Zongze Guo
- Department of Neurosurgery, the First Hospital of China Medical University, Shenyang, China
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12
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The Interferon-Induced Exonuclease ISG20 Exerts Antiviral Activity through Upregulation of Type I Interferon Response Proteins. mSphere 2018; 3:3/5/e00209-18. [PMID: 30232164 PMCID: PMC6147134 DOI: 10.1128/msphere.00209-18] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The host immune responses to infection lead to the production of type I interferon (IFN), and the upregulation of interferon-stimulated genes (ISGs) reduces virus replication and virus dissemination within a host. Ectopic expression of the interferon-induced 20-kDa exonuclease ISG20 suppressed replication of chikungunya virus and Venezuelan equine encephalitis virus, two mosquito-vectored RNA alphaviruses. Since the replication of alphavirus genomes occurs exclusively in the cytoplasm, the mechanism of nucleus-localized ISG20 inhibition of replication is unclear. In this study, we determined that ISG20 acts as a master regulator of over 100 genes, many of which are ISGs. Specifically, ISG20 upregulated IFIT1 genes and inhibited translation of the alphavirus genome. Furthermore, IFIT1-sensitive alphavirus replication was increased in Isg20−/− mice compared to the replication of wild-type viruses but not in cells ectopically expressing ISG20. We propose that ISG20 acts as an indirect regulator of RNA virus replication in the cytoplasm through the upregulation of many other ISGs. Type I interferon (IFN)-stimulated genes (ISGs) have critical roles in inhibiting virus replication and dissemination. Despite advances in understanding the molecular basis of ISG restriction, the antiviral mechanisms of many remain unclear. The 20-kDa ISG ISG20 is a nuclear 3′–5′ exonuclease with preference for single-stranded RNA (ssRNA) and has been implicated in the IFN-mediated restriction of several RNA viruses. Although the exonuclease activity of ISG20 has been shown to degrade viral RNA in vitro, evidence has yet to be presented that virus inhibition in cells requires this activity. Here, we utilized a combination of an inducible, ectopic expression system and newly generated Isg20−/− mice to investigate mechanisms and consequences of ISG20-mediated restriction. Ectopically expressed ISG20 localized primarily to Cajal bodies in the nucleus and restricted replication of chikungunya and Venezuelan equine encephalitis viruses. Although restriction by ISG20 was associated with inhibition of translation of infecting genomic RNA, degradation of viral RNAs was not observed. Instead, translation inhibition of viral RNA was associated with ISG20-induced upregulation of over 100 other genes, many of which encode known antiviral effectors. ISG20 modulated the production of IFIT1, an ISG that suppresses translation of alphavirus RNAs. Consistent with this observation, the pathogenicity of IFIT1-sensitive alphaviruses was increased in Isg20−/− mice compared to that of wild-type viruses but not in cells ectopically expressing ISG20. Our findings establish an indirect role for ISG20 in the early restriction of RNA virus replication by regulating expression of other ISGs that inhibit translation and possibly other activities in the replication cycle. IMPORTANCE The host immune responses to infection lead to the production of type I interferon (IFN), and the upregulation of interferon-stimulated genes (ISGs) reduces virus replication and virus dissemination within a host. Ectopic expression of the interferon-induced 20-kDa exonuclease ISG20 suppressed replication of chikungunya virus and Venezuelan equine encephalitis virus, two mosquito-vectored RNA alphaviruses. Since the replication of alphavirus genomes occurs exclusively in the cytoplasm, the mechanism of nucleus-localized ISG20 inhibition of replication is unclear. In this study, we determined that ISG20 acts as a master regulator of over 100 genes, many of which are ISGs. Specifically, ISG20 upregulated IFIT1 genes and inhibited translation of the alphavirus genome. Furthermore, IFIT1-sensitive alphavirus replication was increased in Isg20−/− mice compared to the replication of wild-type viruses but not in cells ectopically expressing ISG20. We propose that ISG20 acts as an indirect regulator of RNA virus replication in the cytoplasm through the upregulation of many other ISGs.
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Oteiza A, Mechti N. FoxO4 negatively controls Tat-mediated HIV-1 transcription through the post-transcriptional suppression of Tat encoding mRNA. J Gen Virol 2017; 98:1864-1878. [PMID: 28699853 DOI: 10.1099/jgv.0.000837] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The connection between the repression of human immunodeficiency virus type 1(HIV-1) transcription and the resting CD4+ T cell state suggests that the host transcription factors involved in the active maintenance of lymphocyte quiescence are likely to repress the viral transactivator, Tat, thereby restricting HIV-1 transcription. In this study, we analysed the interplay between Tat and the forkhead box transcription factors, FoxO1 and FoxO4. We show that FoxO1 and FoxO4 antagonize Tat-mediated transactivation of HIV-1 promoter through the repression of Tat protein expression. No effect was observed on the expression of two HIV-1 accessory proteins, Vif and Vpr. Unexpectedly, we found that FoxO1 and FoxO4 expression causes a strong dose-dependent post-transcriptional suppression of Tat mRNA, indicating that FoxO should effectively inhibit HIV-1 replication by destabilizing Tat mRNA and suppressing Tat-mediated HIV-1 transcription. In accordance with this, we observed that the Tat mRNA half-life is reduced by FoxO4 expression. The physiological relevance of our findings was validated using the J-Lat 10.6 model of latently infected cells. We demonstrated that the overexpression of a constitutively active FoxO4-TM mutant antagonized HIV-1 transcription reactivation in response to T cell activators, such as TNF-α or PMA. Altogether, our findings demonstrate that FoxO factors can control HIV-1 transcription and provide new insights into their potential role during the establishment of HIV-1 latency.
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Affiliation(s)
- Alexandra Oteiza
- CNRS UMR5235, DIMNP, Université de Montpellier, Bat 24, CC107, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Nadir Mechti
- CNRS UMR5235, DIMNP, Université de Montpellier, Bat 24, CC107, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
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14
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Liu Y, Nie H, Mao R, Mitra B, Cai D, Yan R, Guo JT, Block TM, Mechti N, Guo H. Interferon-inducible ribonuclease ISG20 inhibits hepatitis B virus replication through directly binding to the epsilon stem-loop structure of viral RNA. PLoS Pathog 2017; 13:e1006296. [PMID: 28399146 PMCID: PMC5388505 DOI: 10.1371/journal.ppat.1006296] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/15/2017] [Indexed: 12/11/2022] Open
Abstract
Hepatitis B virus (HBV) replicates its DNA genome through reverse transcription of a viral RNA pregenome. We report herein that the interferon (IFN) stimulated exoribonuclease gene of 20 KD (ISG20) inhibits HBV replication through degradation of HBV RNA. ISG20 expression was observed at basal level and was highly upregulated upon IFN treatment in hepatocytes, and knock down of ISG20 resulted in elevation of HBV replication and attenuation of IFN-mediated antiviral effect. The sequence element conferring the susceptibility of HBV RNA to ISG20-mediated RNA degradation was mapped at the HBV RNA terminal redundant region containing epsilon (ε) stem-loop. Furthermore, ISG20-induced HBV RNA degradation relies on its ribonuclease activity, as the enzymatic inactive form ISG20D94G was unable to promote HBV RNA decay. Interestingly, ISG20D94G retained antiviral activity against HBV DNA replication by preventing pgRNA encapsidation, resulting from a consequence of ISG20-ε interaction. This interaction was further characterized by in vitro electrophoretic mobility shift assay (EMSA) and ISG20 was able to bind HBV ε directly in absence of any other cellular proteins, indicating a direct ε RNA binding capability of ISG20; however, cofactor(s) may be required for ISG20 to efficiently degrade ε. In addition, the lower stem portion of ε is the major ISG20 binding site, and the removal of 4 base pairs from the bottom portion of ε abrogated the sensitivity of HBV RNA to ISG20, suggesting that the specificity of ISG20-ε interaction relies on both RNA structure and sequence. Furthermore, the C-terminal Exonuclease III (ExoIII) domain of ISG20 was determined to be responsible for interacting with ε, as the deletion of ExoIII abolished in vitro ISG20-ε binding and intracellular HBV RNA degradation. Taken together, our study sheds light on the underlying mechanisms of IFN-mediated HBV inhibition and the antiviral mechanism of ISG20 in general. HBV is a DNA virus but replicates its DNA via retrotranscription of a viral RNA pregenome. ISG20, an antiviral RNase induced by interferons, inhibits the replication of many RNA viruses but the underlying molecular antiviral mechanism remains elusive. Since all the known viruses, except for prions, have RNA products in their life cycles, ISG20 can be a broad spectrum antiviral protein; but in order to distinguish viral RNA from host RNA, ISG20 may have evolved to recognize virus-specific signals as its antiviral target. We demonstrated herein that ISG20 selectively binds to a unique stem-loop structure called epsilon (ε) in all HBV RNA species and degrades viral RNA to inhibit HBV replication. Because ε is the HBV pregenomic RNA packaging signal and reverse transcription priming site, the binding of ISG20 to ε, even in the absence of ribonuclease activity, results in antiviral effect to prevent DNA replication due to preventing viral polymerase binding to pgRNA. We also determined the structure and sequence requirements of ε RNA and ISG20 protein for ISG20-ε binding and antiviral activity. Such information will aid the function study of ISG20 against viral pathogens in host innate defense, and ISG20 has potentials to be developed into a therapeutic agent for viral diseases including hepatitis B.
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Affiliation(s)
- Yuanjie Liu
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Hui Nie
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Richeng Mao
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Bidisha Mitra
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Dawei Cai
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Ran Yan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Ju-Tao Guo
- Baruch S. Blumberg Institute, Doylestown, Pennsylvania, United States of America
| | - Timothy M. Block
- Baruch S. Blumberg Institute, Doylestown, Pennsylvania, United States of America
| | - Nadir Mechti
- CNRS, UMR5235, DIMNP, University of Montpellier 2, Montpellier, France
| | - Haitao Guo
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail:
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15
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Zheng Z, Wang L, Pan J. Interferon-stimulated gene 20-kDa protein (ISG20) in infection and disease: Review and outlook. Intractable Rare Dis Res 2017; 6:35-40. [PMID: 28357179 PMCID: PMC5359350 DOI: 10.5582/irdr.2017.01004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Interferon-stimulated exonuclease gene 20 (ISG20) is an RNA exonuclease in the yeast RNA exonuclease 4 homolog (REX4) subfamily and the DEDDh exonuclease family, and this gene codes for a 20-kDa protein. Those exonucleases are involved in cleaving single-stranded RNA and DNA. ISG20 is also referred to as HEM45 (HeLa estrogen-modulated, band 45). Expression of ISG20 can be induced or regulated by both type I and II interferons (IFNs) in various cell lines. ISG20 plays a role in mediating interferon's antiviral activities. In addition, ISG20 may be a potential susceptibility biomarker or pharmacological target in some inflammatory conditions. Exonucleases are useful components of many physiological processes. Despite recent advances in our understanding of the functions of ISG20, much work remains to be done with regard to uncovering the mechanism of action of ISG20 in specific diseases and adapting ISG20 for use as a biomarker of disease. This review describes current information on ISG20 and its potential use in marking disease. This review describes several research achievements thus far and it seeks to provide some new ideas for future related research.
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Affiliation(s)
- Zhiwei Zheng
- Shandong Medicinal Biotechnology Center, Ji'nan, China
- Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Ji'nan, China
- Key Laboratory for Biotech-drugs of the Ministry of Health, Ji'nan, China
- School of Medicine and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, Ji'nan, China
| | - Lin Wang
- Shandong Medicinal Biotechnology Center, Ji'nan, China
- Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Ji'nan, China
- Key Laboratory for Biotech-drugs of the Ministry of Health, Ji'nan, China
| | - Jihong Pan
- Shandong Medicinal Biotechnology Center, Ji'nan, China
- Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Ji'nan, China
- Key Laboratory for Biotech-drugs of the Ministry of Health, Ji'nan, China
- Address correspondence to: Dr. Jihong Pan, Shandong Medicinal and Biotechnology Center, Shandong Academy of Medical Sciences, 18877 Jingshi Road, Ji'nan, Shandong 250062, China. E-mail:
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16
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Hagen L, Sharma A, Aas PA, Slupphaug G. Off-target responses in the HeLa proteome subsequent to transient plasmid-mediated transfection. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1854:84-90. [PMID: 25448019 DOI: 10.1016/j.bbapap.2014.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 10/16/2014] [Accepted: 10/20/2014] [Indexed: 11/16/2022]
Abstract
Transient transfection of mammalian cells with plasmid expression vectors and chemical transfection reagents is widely used to study protein transport and dynamics as well as phenotypic alterations mediated by the overexpressed protein. Despite the undisputed impact of this technique, surprisingly little is known about the cellular effects mediated by the transfection process per se. Conceivably, off-target effects could have implications upon proteins or processes being studied and understanding the molecular pathways affected would add value to the interpretation of experimental observations subsequent to cell transfection. Here we have used a SILAC-based proteomic approach to study differentially expressed proteins after transfection of HeLa cells with ECFP vector using a commonly employed non-liposome based transfection reagent, Fugene®HD. Whereas the transfection reagent itself mediated minimal effects upon protein expression, 11 proteins were found to be significantly upregulated after transfection, all of which were associated with an interferon type I/II response. The upregulated proteins might potentially inflict major cellular processes such as RNA splicing, chromatin remodeling, post-translational protein modification and cell cycle control. The results were validated by western analysis as well as quantitative RT-PCR and this demonstrated that an essentially identical response was induced in HeLa by transfection using an empty pUC18 vector, which does not contain a mammalian virus promoter, as well as a liposome-based transfection reagent, Lipofectamine(TM)2000. Notably, no induction of the interferon response was observed in HEK293 cells, suggesting that these cells might be preferable to HeLa to avoid undesired off-target effects in transfection studies encompassing interferon-signaling and antiviral responses.
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Affiliation(s)
- Lars Hagen
- Department of Cancer Research and Molecular Medicine and PROMEC Core Facility for Proteomics and Metabolomics, Norwegian University of Science and Technology, NTNU, N-7491 Trondheim, Norway
| | - Animesh Sharma
- Department of Cancer Research and Molecular Medicine and PROMEC Core Facility for Proteomics and Metabolomics, Norwegian University of Science and Technology, NTNU, N-7491 Trondheim, Norway
| | - Per Arne Aas
- Department of Cancer Research and Molecular Medicine and PROMEC Core Facility for Proteomics and Metabolomics, Norwegian University of Science and Technology, NTNU, N-7491 Trondheim, Norway
| | - Geir Slupphaug
- Department of Cancer Research and Molecular Medicine and PROMEC Core Facility for Proteomics and Metabolomics, Norwegian University of Science and Technology, NTNU, N-7491 Trondheim, Norway.
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17
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Katsounas A, Rasimas JJ, Schlaak JF, Lempicki RA, Rosenstein DL, Kottilil S. Interferon stimulated exonuclease gene 20 kDa links psychiatric events to distinct hepatitis C virus responses in human immunodeficiency virus positive patients. J Med Virol 2014; 86:1323-31. [PMID: 24782267 PMCID: PMC4114765 DOI: 10.1002/jmv.23956] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2014] [Indexed: 01/02/2023]
Abstract
Hepatitis C Virus (HCV) infection occurs frequently in patients with preexisting mental illness. Treatment for chronic hepatitis C using interferon formulations often increases risk for neuro-psychiatric symptoms. Pegylated-Interferon-α (PegIFN-α) remains crucial for attaining sustained virologic response (SVR); however, PegIFN-α based treatment is associated with psychiatric adverse effects, which require dose reduction and/or interruption. This study's main objective was to identify genes induced by PegIFN-α and expressed in the central nervous system and immune system, which could mediate the development of psychiatric toxicity in association with antiviral outcome. Using peripheral blood mononuclear cells from Human Immunodeficiency Virus (HIV)/HCV co-infected donors (N = 28), DNA microarray analysis was performed and 21 differentially regulated genes were identified in patients with psychiatric toxicity versus those without. Using these 21 expression profiles a two-way-ANOVA was performed to select genes based on antiviral outcome and occurrence of neuro-psychiatric adverse events. Microarray analysis demonstrated that Interferon-stimulated-exonuclease-gene 20 kDa (ISG20) and Interferon-alpha-inducible-protein 27 (IFI27) were the most regulated genes (P < 0.05) between three groups that were built by combining antiviral outcome and neuro-psychiatric toxicity. Validation by bDNA assay confirmed that ISG20 expression levels were significantly associated with these outcomes (P < 0.035). Baseline levels and induction of ISG20 correlated independently with no occurrence of psychiatric adverse events and non-response to therapy (P < 0.001). Among the 21 genes that were associated with psychiatric adverse events and 20 Interferon-inducible genes (IFIGs) used as controls, only ISG20 expression was able to link PegIFN-α related neuro-psychiatric toxicity to distinct HCV-responses in patients co-infected with HIV and HCV in vivo.
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Affiliation(s)
- Antonios Katsounas
- Department of Gastroenterology and Hepatology, University Hospital Essen, Hufelandstrasse 55, 45147 Essen, Germany
| | - Joseph J. Rasimas
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joerg F. Schlaak
- Department of Gastroenterology and Hepatology, University Hospital Essen, Hufelandstrasse 55, 45147 Essen, Germany
| | - Richard A. Lempicki
- Laboratory of Immunopathogenesis and Bioinformatics, SAIC-Frederick, Inc, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Donald L. Rosenstein
- Department of Psychiatry, University of North Carolina at Chapel Hill, NC 27599-7305, USA
| | - Shyam Kottilil
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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18
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Abstract
Hepatitis C virus (HCV) infection is curable by therapy. The antiviral treatment of chronic hepatitis C has been based for decades on the use of interferon (IFN)-α, combined with ribavirin. More recently, new therapeutic approaches that target essential components of the HCV life cycle have been developed, including direct-acting antiviral (DAA) and host-targeted agents (HTA). A new standard-of-care treatment has been approved in 2011 for patients infected with HCV genotype 1, based on a triple combination of pegylated IFN-α, ribavirin, and either telaprevir or boceprevir, two inhibitors of the HCV protease. New triple and quadruple combination therapies including pegylated IFN-α, ribavirin, and one or two DAAs/HTAs, respectively, are currently being evaluated in Phase II and III clinical trials. In addition, various options for all-oral, IFN-free regimens are currently being evaluated. This chapter describes the characteristics of the different drugs used in the treatment of chronic hepatitis C and those currently in development and provides an overview of the current and future standard-of-care treatments of chronic hepatitis C.
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Affiliation(s)
- Jean-Michel Pawlotsky
- National Reference Center for Viral Hepatitis B, C and D, Department of Virology, Hôpital Henri Mondor, Université Paris-Est, Créteil, France.
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Machyna M, Heyn P, Neugebauer KM. Cajal bodies: where form meets function. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:17-34. [PMID: 23042601 DOI: 10.1002/wrna.1139] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cell nucleus contains dozens of subcompartments that separate biochemical processes into confined spaces. Cajal bodies (CBs) were discovered more than 100 years ago, but only extensive research in the past decades revealed the surprising complexity of molecular and cellular functions taking place in these structures. Many protein and RNA species are modified and assembled within CBs, which have emerged as a meeting place and factory for ribonucleoprotein (RNP) particles involved in splicing, ribosome biogenesis and telomere maintenance. Recently, a distinct structure near histone gene clusters--the Histone locus body (HLB)--was discovered. Involved in histone mRNA 3'-end formation, HLBs can share several components with CBs. Whether the appearance of distinct HLBs is simply a matter of altered affinity between these structures or of an alternate mode of CB assembly is unknown. However, both structures share basic assembly properties, in which transcription plays a decisive role in initiation. After this seeding event, additional components associate in random order. This appears to be a widespread mechanism for body assembly. CB assembly encompasses an additional layer of complexity, whereby a set of pre-existing substructures can be integrated into mature CBs. We propose this as a multi-seeding model of CB assembly.
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Affiliation(s)
- Martin Machyna
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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Goff SA. A unifying theory for general multigenic heterosis: energy efficiency, protein metabolism, and implications for molecular breeding. THE NEW PHYTOLOGIST 2011; 189:923-937. [PMID: 21166808 DOI: 10.1111/j.1469-8137.2010.03574.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Hybrids between genetically diverse varieties display enhanced growth, and increased total biomass, stress resistance and grain yield. Gene expression and metabolic studies in maize, rice and other species suggest that protein metabolism plays a role in the growth differences between hybrids and inbreds. Single trait heterosis can be explained by the existing theories of dominance, overdominance and epistasis. General multigenic heterosis is observed in a wide variety of different species and is likely to share a common underlying biological mechanism. This review presents a model to explain differences in growth and yield caused by general multigenic heterosis. The model describes multigenic heterosis in terms of energy-use efficiency and faster cell cycle progression where hybrids have more efficient growth than inbreds because of differences in protein metabolism. The proposed model is consistent with the observed variation of gene expression in different pairs of inbred lines and hybrid offspring as well as growth differences in polyploids and aneuploids. It also suggests an approach to enhance yield gains in both hybrid and inbred crops via the creation of an appropriate computational analysis pipeline coupled to an efficient molecular breeding program.
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Affiliation(s)
- Stephen A Goff
- iPlant Collaborative, BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA
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21
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Coady TH, Lorson CL. SMN in spinal muscular atrophy and snRNP biogenesis. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:546-64. [PMID: 21957043 DOI: 10.1002/wrna.76] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ribonucleoprotein (RNP) complexes function in nearly every facet of cellular activity. The spliceosome is an essential RNP that accurately identifies introns and catalytically removes the intervening sequences, providing exquisite control of spatial, temporal, and developmental gene expressions. U-snRNPs are the building blocks for the spliceosome. A significant amount of insight into the molecular assembly of these essential particles has recently come from a seemingly unexpected area of research: neurodegeneration. Survival motor neuron (SMN) performs an essential role in the maturation of snRNPs, while the homozygous loss of SMN1 results in the development of spinal muscular atrophy (SMA), a devastating neurodegenerative disease. In this review, the function of SMN is examined within the context of snRNP biogenesis and evidence is examined which suggests that the SMN functional defects in snRNP biogenesis may account for the motor neuron pathology observed in SMA.
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Affiliation(s)
- Tristan H Coady
- Department of Veterinary Pathobiology, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
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Zhou Z, Wang N, Woodson SE, Dong Q, Wang J, Liang Y, Rijnbrand R, Wei L, Nichols JE, Guo JT, Holbrook MR, Lemon SM, Li K. Antiviral activities of ISG20 in positive-strand RNA virus infections. Virology 2010; 409:175-88. [PMID: 21036379 PMCID: PMC3018280 DOI: 10.1016/j.virol.2010.10.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 08/05/2010] [Accepted: 10/06/2010] [Indexed: 01/19/2023]
Abstract
ISG20 is an interferon-inducible 3′–5′ exonuclease that inhibits replication of several human and animal RNA viruses. However, the specificities of ISG20's antiviral action remain poorly defined. Here we determine the impact of ectopic expression of ISG20 on replication of several positive-strand RNA viruses from distinct viral families. ISG20 inhibited infections by cell culture-derived hepatitis C virus (HCV) and a pestivirus, bovine viral diarrhea virus and a picornavirus, hepatitis A virus. Moreover, ISG20 demonstrated cell-type specific antiviral activity against yellow fever virus, a classical flavivirus. Overexpression of ISG20, however, did not inhibit propagation of severe acute respiratory syndrome coronavirus, a highly-pathogenic human coronavirus in Huh7.5 cells. The antiviral effects of ISG20 were all dependent on its exonuclease activity. The closely related cellular exonucleases, ISG20L1 and ISG20L2, did not inhibit HCV replication. Together, these data may help better understand the antiviral specificity and action of ISG20.
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Affiliation(s)
- Zhi Zhou
- Department of Microbiology and Immunology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
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Rossoll W, Bassell GJ. Spinal muscular atrophy and a model for survival of motor neuron protein function in axonal ribonucleoprotein complexes. Results Probl Cell Differ 2009; 48:289-326. [PMID: 19343312 PMCID: PMC3718852 DOI: 10.1007/400_2009_4] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease that results from loss of function of the SMN1 gene, encoding the ubiquitously expressed survival of motor neuron (SMN) protein, a protein best known for its housekeeping role in the SMN-Gemin multiprotein complex involved in spliceosomal small nuclear ribonucleoprotein (snRNP) assembly. However, numerous studies reveal that SMN has many interaction partners, including mRNA binding proteins and actin regulators, suggesting its diverse role as a molecular chaperone involved in mRNA metabolism. This review focuses on studies suggesting an important role of SMN in regulating the assembly, localization, or stability of axonal messenger ribonucleoprotein (mRNP) complexes. Various animal models for SMA are discussed, and phenotypes described that indicate a predominant function for SMN in neuronal development and synapse formation. These models have begun to be used to test different therapeutic strategies that have the potential to restore SMN function. Further work to elucidate SMN mechanisms within motor neurons and other cell types involved in neuromuscular circuitry hold promise for the potential treatment of SMA.
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Affiliation(s)
- Wilfried Rossoll
- Departments of Cell Biology and Neurology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Patel SB, Bellini M. The assembly of a spliceosomal small nuclear ribonucleoprotein particle. Nucleic Acids Res 2008; 36:6482-93. [PMID: 18854356 PMCID: PMC2582628 DOI: 10.1093/nar/gkn658] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The U1, U2, U4, U5 and U6 small nuclear ribonucleoprotein particles (snRNPs) are essential elements of the spliceosome, the enzyme that catalyzes the excision of introns and the ligation of exons to form a mature mRNA. Since their discovery over a quarter century ago, the structure, assembly and function of spliceosomal snRNPs have been extensively studied. Accordingly, the functions of splicing snRNPs and the role of various nuclear organelles, such as Cajal bodies (CBs), in their nuclear maturation phase have already been excellently reviewed elsewhere. The aim of this review is, then, to briefly outline the structure of snRNPs and to synthesize new and exciting developments in the snRNP biogenesis pathways.
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Affiliation(s)
- Snehal Bhikhu Patel
- Biochemistry and College of Medicine and Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Identification of three interferon-inducible cellular enzymes that inhibit the replication of hepatitis C virus. J Virol 2007; 82:1665-78. [PMID: 18077728 DOI: 10.1128/jvi.02113-07] [Citation(s) in RCA: 228] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Hepatitis C virus (HCV) infection is a common cause of chronic hepatitis and is currently treated with alpha interferon (IFN-alpha)-based therapies. However, the underlying mechanism of IFN-alpha therapy remains to be elucidated. To identify the cellular proteins that mediate the antiviral effects of IFN-alpha, we created a HEK293-based cell culture system to inducibly express individual interferon-stimulated genes (ISGs) and determined their antiviral effects against HCV. By screening 29 ISGs that are induced in Huh7 cells by IFN-alpha and/or up-regulated in HCV-infected livers, we discovered that viperin, ISG20, and double-stranded RNA-dependent protein kinase (PKR) noncytolytically inhibited the replication of HCV replicons. Mechanistically, inhibition of HCV replication by ISG20 and PKR depends on their 3'-5' exonuclease and protein kinase activities, respectively. Moreover, our work, for the first time, provides strong evidence suggesting that viperin is a putative radical S-adenosyl-l-methionine (SAM) enzyme. In addition to demonstrating that the antiviral activity of viperin depends on its radical SAM domain, which contains conserved motifs to coordinate [4Fe-4S] cluster and cofactor SAM and is essential for its enzymatic activity, mutagenesis studies also revealed that viperin requires an aromatic amino acid residue at its C terminus for proper antiviral function. Furthermore, although the N-terminal 70 amino acid residues of viperin are not absolutely required, deletion of this region significantly compromises its antiviral activity against HCV. Our findings suggest that viperin represents a novel antiviral pathway that works together with other antiviral proteins, such as ISG20 and PKR, to mediate the IFN response against HCV infection.
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Couté Y, Kindbeiter K, Belin S, Dieckmann R, Duret L, Bezin L, Sanchez JC, Diaz JJ. ISG20L2, a novel vertebrate nucleolar exoribonuclease involved in ribosome biogenesis. Mol Cell Proteomics 2007; 7:546-59. [PMID: 18065403 DOI: 10.1074/mcp.m700510-mcp200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Proteomics analyses of human nucleoli provided molecular bases for an understanding of the multiple functions fulfilled by these nuclear domains. However, the biological roles of about 100 of the identified proteins are unpredictable. The present study describes the functional characterization of one of these proteins, ISG20L2. We demonstrate that ISG20L2 is a 3' to 5' exoribonuclease involved in ribosome biogenesis at the level of 5.8 S rRNA maturation, more specifically in the processing of the 12 S precursor rRNA. The use of truncated forms of ISG20L2 demonstrated that its N-terminal half promotes the nucleolar localization and suggested that its C-terminal half bears the exoribonuclease activity. Identification of the binding partners of ISG20L2 confirmed its involvement in the biogenesis of the large ribosomal subunit. These results strongly support the notion that, in human, as it was demonstrated in yeast, 5.8 S rRNA maturation requires several proteins in addition to the exosome complex. Furthermore this observation greatly sustains the idea that the extremely conserved need for correctly processed rRNAs in vertebrates and yeast is achieved by close but different mechanisms.
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Affiliation(s)
- Yohann Couté
- Biomedical Proteomics Research Group, Département de Biologie Structurale et Bioinformatique, Centre Médical Universitaire, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland.
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Chevaliez S, Pawlotsky JM. Interferon-based therapy of hepatitis C. Adv Drug Deliv Rev 2007; 59:1222-41. [PMID: 17869375 DOI: 10.1016/j.addr.2007.07.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Accepted: 07/23/2007] [Indexed: 02/06/2023]
Abstract
In 2007, the world celebrated the 50th anniversary of the discovery of interferon (IFN). The first clinical trial of recombinant IFN-alpha in patients with chronic hepatitis C was published in 1986. This article reviews the classification of IFNs, IFN production during viral infections, IFN signaling pathways and the mechanisms of their antiviral and immunomodulatory properties. Hepatitis C virus infection treatment is currently based on the combination of pegylated IFN-alpha and ribavirin. The pegylated IFN-alpha molecules are described, as well as the putative mechanisms of action of ribavirin. Current treatment guidelines are discussed and new results suggesting that the treatment schedule should be tailored to the early virological response during therapy are presented. Finally, insights into new hepatitis C drug developments are given.
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Affiliation(s)
- Stéphane Chevaliez
- French National Reference Center for Viral Hepatitis B, C and delta, Department of Virology, Hôpital Henri Mondor, Université Paris 12, Créteil, France
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Degols G, Eldin P, Mechti N. ISG20, an actor of the innate immune response. Biochimie 2007; 89:831-5. [PMID: 17445960 DOI: 10.1016/j.biochi.2007.03.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 03/08/2007] [Indexed: 12/01/2022]
Abstract
The interferon (IFN) system is a major effector of the innate immunity that allows time for the subsequent establishment of an adaptive immune response against wide-range pathogens. The effectiveness of IFN to control initial infection requires the cooperation between several pathways induced in the target cells. Recent studies that highlight the implication of the 3'-5' exonuclease ISG20 (IFN Stimulated Gene product of 20 kDa) in the host's defenses against pathogens are summarised in this review.
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Affiliation(s)
- Genevieve Degols
- UMR5160 CNRS, EFS, 240 Avenue Emile Jeanbrau, 34094 Montpellier Cedex 5, France
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Abstract
The molecular basis of spinal muscular atrophy (SMA), an autosomal recessive neuromuscular disorder, is the homozygous loss of the survival motor neuron gene 1 (SMN1). A nearly identical copy of the SMN1 gene, called SMN2, modulates the disease severity. The functional difference between both genes is a translationally silent mutation that, however, disrupts an exonic splicing enhancer causing exon 7 skipping in most SMN2 transcripts. Only 10% of SMN2 transcripts encode functional full-length protein identical to SMN1. Transcriptional activation, facilitation of correct SMN2 splicing, or stabilization of the protein are considered as strategies for SMA therapy. Among various drugs, histone deacetylase inhibitors such as valproic acid (VPA) or 4-phenylbutyrate (PBA) have been shown to increase SMN2-derived RNA and protein levels. Recently, in vivo activation of the SMN gene was shown in VPA-treated SMA patients and carriers. Clinical trials are underway to investigate the effect of VPA and PBA on motor function in SMA patients.
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Affiliation(s)
- Brunhilde Wirth
- Institute of Human Genetics, Institute of Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
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