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Williams HM, Thorkelsson S, Vogel D, Busch C, Milewski M, Cusack S, Grünewald K, Quemin EJ, Rosenthal M. Structural snapshots of phenuivirus cap-snatching and transcription. Nucleic Acids Res 2024; 52:6049-6065. [PMID: 38709882 PMCID: PMC11162785 DOI: 10.1093/nar/gkae330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/10/2024] [Accepted: 04/19/2024] [Indexed: 05/08/2024] Open
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a human pathogen that is now endemic to several East Asian countries. The viral large (L) protein catalyzes viral transcription by stealing host mRNA caps via a process known as cap-snatching. Here, we establish an in vitro cap-snatching assay and present three high-quality electron cryo-microscopy (cryo-EM) structures of the SFTSV L protein in biologically relevant, transcription-specific states. In a priming-state structure, we show capped RNA bound to the L protein cap-binding domain (CBD). The L protein conformation in this priming structure is significantly different from published replication-state structures, in particular the N- and C-terminal domains. The capped-RNA is positioned in a way that it can feed directly into the RNA-dependent RNA polymerase (RdRp) ready for elongation. We also captured the L protein in an early-elongation state following primer-incorporation demonstrating that this priming conformation is retained at least in the very early stages of primer extension. This structural data is complemented by in vitro biochemical and cell-based assays. Together, these insights further our mechanistic understanding of how SFTSV and other bunyaviruses incorporate stolen host mRNA fragments into their viral transcripts thereby allowing the virus to hijack host cell translation machinery.
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Affiliation(s)
- Harry M Williams
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
| | - Sigurdur R Thorkelsson
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Dominik Vogel
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Carola Busch
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Morlin Milewski
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | | | - Kay Grünewald
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Emmanuelle R J Quemin
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology, Hamburg, Germany
- Department of Virology, Institute for Integrative Biology of the Cell (I2BC), Centre National de la Recherche Scientifique (CNRS) UMR9198, Gif-sur-Yvette, France
| | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Hamburg, Germany
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Li JC, Zhao J, Li H, Fang LQ, Liu W. Epidemiology, clinical characteristics, and treatment of severe fever with thrombocytopenia syndrome. INFECTIOUS MEDICINE 2022; 1:40-49. [PMID: 38074982 PMCID: PMC10699716 DOI: 10.1016/j.imj.2021.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 02/23/2024]
Abstract
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease caused by a novel phlebovirus (SFTS virus, SFTSV) in the family Phenuiviridae of the order Bunyavirales. The disease causes a wide spectrum of clinical signs and symptoms, ranging from mild febrile disease accompanied by thrombocytopenia and/or leukocytopenia to hemorrhagic fever, encephalitis, multiple organ failure, and death. SFTS was first identified in China and was subsequently reported in South Korea and Japan. The case-fatality rate ranges from 2.7% to 45.7%. Older age has been consistently shown to be the most important predictor of adverse disease outcomes. Older age exacerbates disease mainly through dysregulation of host immune cells and uncontrolled inflammatory responses. Tick-to-human transmission is the primary route of human infection with SFTSV, and Haemaphysalis longicornis is the primary tick vector of SFTSV. Despite its high case-fatality rate, vaccines and antiviral therapies for SFTS are not currently available. The therapeutic efficacies of several antiviral agents against SFTSV are currently being evaluated. Ribavirin was initially identified as a potential antiviral therapy for SFTS but was subsequently found to inefficiently improve disease outcomes, especially among patients with high viral loads. Favipiravir (T705) decreased both time to clinical improvement and mortality when administered early in patients with low viral loads. Anti-inflammatory agents including corticosteroids have been proposed to play therapeutic roles. However, the efficacy of other therapeutic modalities, such as convalescent plasma, is not yet clear.
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Affiliation(s)
| | | | - Hao Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Li-Qun Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Wei Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
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3
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Li J, Li S, Yang L, Cao P, Lu J. Severe fever with thrombocytopenia syndrome virus: a highly lethal bunyavirus. Crit Rev Microbiol 2020; 47:112-125. [PMID: 33245676 DOI: 10.1080/1040841x.2020.1847037] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a novel bunyavirus. Since 2007, SFTS disease has been reported in China with high fatality rate up to 30%, which drew high attention from Centre for Disease Control and Prevention and government. SFTSV is endemic in the centra l and eastern China, Korea and Japan. There also have been similar cases reported in Vietnam. The number of SFTSV infection cases has a steady growth in these years. As SFTSV could transmitted from person to person, it will expose the public to infectious risk. In 2018 annual review of the Blueprint list of priority diseases, World Health Organisation has listed SFTSV infection as prioritised diseases for research and development in emergency contexts. However, the pathogenesis of SFTSV remains largely unclear. Currently, there are no specific therapeutics or vaccines to combat infections of SFTSV. This review discusses recent findings of epidemiology, transmission pathway, pathogenesis and treatments of SFTS disease.
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Affiliation(s)
- Jing Li
- NHC Key Laboratory of Carcinogenesis, Department of Hematology, Xiangya Hospital, Central South University, Changsha, China.,Department of Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China.,China-Africa Research Center of Infectious Diseases, Central South University, Changsha, China
| | - Shen Li
- NHC Key Laboratory of Carcinogenesis, Department of Hematology, Xiangya Hospital, Central South University, Changsha, China.,Department of Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China.,China-Africa Research Center of Infectious Diseases, Central South University, Changsha, China
| | - Li Yang
- NHC Key Laboratory of Carcinogenesis, Department of Hematology, Xiangya Hospital, Central South University, Changsha, China.,Department of Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China.,China-Africa Research Center of Infectious Diseases, Central South University, Changsha, China
| | - Pengfei Cao
- NHC Key Laboratory of Carcinogenesis, Department of Hematology, Xiangya Hospital, Central South University, Changsha, China.,Department of Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China.,China-Africa Research Center of Infectious Diseases, Central South University, Changsha, China
| | - Jianhong Lu
- NHC Key Laboratory of Carcinogenesis, Department of Hematology, Xiangya Hospital, Central South University, Changsha, China.,Department of Microbiology, School of Basic Medical Sciences, Central South University, Changsha, China.,China-Africa Research Center of Infectious Diseases, Central South University, Changsha, China
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Huang XY, He ZQ, Wang BH, Hu K, Li Y, Guo WS. Severe fever with thrombocytopenia syndrome virus: a systematic review and meta-analysis of transmission mode. Epidemiol Infect 2020; 148:e239. [PMID: 32993819 PMCID: PMC7584033 DOI: 10.1017/s0950268820002290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 11/29/2022] Open
Abstract
Severe fever with thrombocytopenia syndrome (SFTS) is a disease with a high case-fatality rate that is caused by infection with the SFTS virus (SFTSV). Five electronic databases were systematically searched to identify relevant articles published from 1 January 2011 to 1 December 2019. The pooled rates with 95% confidence interval (CI) were calculated by a fixed-effect or random-effect model analysis. The results showed that 92 articles were included in this meta-analysis. For the confirmed SFTS cases, the case-fatality rate was 0.15 (95% CI 0.11, 0.18). Two hundred and ninety-six of 1384 SFTS patients indicated that they had been bitten by ticks and the biting rate was 0.21 (95% CI 0.16, 0.26). The overall pooled seroprevalence of SFTSV antibodies among the healthy population was 0.04 (95% CI 0.03, 0.05). For the overall seroprevalence of SFTSV in animals, the seroprevalence of SFTSV was 0.25 (95% CI 0.20, 0.29). The infection rate of SFTSV in ticks was 0.08 (95% CI 0.05, 0.11). In conclusion, ticks can serve as transmitting vectors of SFTSVs and reservoir hosts. Animals can be infected by tick bites, and as a reservoir host, SFTSV circulates continuously between animals and ticks in nature. Humans are infected by tick bites and direct contact with patient secretions.
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Affiliation(s)
- X. Y. Huang
- Henan Province Center for Disease Control and Prevention, Zhengzhou, China
- Henan Key Laboratory of Pathogenic Microorganisms, Zhengzhou, China
| | - Z. Q. He
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - B. H. Wang
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - K. Hu
- Henan Academy of Medical Sciences, Zhengzhou, China
| | - Y. Li
- Henan Province Center for Disease Control and Prevention, Zhengzhou, China
- Henan Key Laboratory of Pathogenic Microorganisms, Zhengzhou, China
| | - W. S. Guo
- Henan Province Center for Disease Control and Prevention, Zhengzhou, China
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