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Xia S, Chen Z, Shen C, Fu TM. Higher-order assemblies in immune signaling: supramolecular complexes and phase separation. Protein Cell 2021; 12:680-694. [PMID: 33835418 PMCID: PMC8403095 DOI: 10.1007/s13238-021-00839-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/01/2021] [Indexed: 12/31/2022] Open
Abstract
Signaling pathways in innate and adaptive immunity play vital roles in pathogen recognition and the functions of immune cells. Higher-order assemblies have recently emerged as a central principle that governs immune signaling and, by extension, cellular communication in general. There are mainly two types of higher-order assemblies: 1) ordered, solid-like large supramolecular complexes formed by stable and rigid protein-protein interactions, and 2) liquid-like phase-separated condensates formed by weaker and more dynamic intermolecular interactions. This review covers key examples of both types of higher-order assemblies in major immune pathways. By placing emphasis on the molecular structures of the examples provided, we discuss how their structural organization enables elegant mechanisms of signaling regulation.
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MESH Headings
- Adaptive Immunity
- Animals
- DEAD Box Protein 58/genetics
- DEAD Box Protein 58/immunology
- DEAD Box Protein 58/metabolism
- DEAD-box RNA Helicases/genetics
- DEAD-box RNA Helicases/immunology
- DEAD-box RNA Helicases/metabolism
- Gene Expression Regulation
- Humans
- Immunity, Innate
- Inflammasomes/genetics
- Inflammasomes/immunology
- Inflammasomes/ultrastructure
- Models, Molecular
- Multiprotein Complexes/genetics
- Multiprotein Complexes/immunology
- Multiprotein Complexes/metabolism
- Protein Conformation
- Protein Interaction Mapping
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/immunology
- Receptors, Immunologic/metabolism
- Receptors, Tumor Necrosis Factor, Type I/genetics
- Receptors, Tumor Necrosis Factor, Type I/immunology
- Receptors, Tumor Necrosis Factor, Type I/metabolism
- Signal Transduction/immunology
- Toll-Like Receptors/genetics
- Toll-Like Receptors/immunology
- Toll-Like Receptors/metabolism
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Affiliation(s)
- Shiyu Xia
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Zhenhang Chen
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
| | - Chen Shen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Tian-Min Fu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA.
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA.
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Probing DNA-protein interactions using single-molecule diffusivity contrast. BIOPHYSICAL REPORTS 2021; 1:100009. [PMID: 36425309 PMCID: PMC9680706 DOI: 10.1016/j.bpr.2021.100009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/20/2021] [Indexed: 11/28/2022]
Abstract
Single-molecule fluorescence investigations of protein-nucleic acid interactions require robust means to identify the binding state of individual substrate molecules in real time. Here, we show that diffusivity contrast, widely used in fluorescence correlation spectroscopy at the ensemble level and in single-particle tracking on individual (but slowly diffusing) species, can be used as a general readout to determine the binding state of single DNA molecules with unlabeled proteins in solution. We first describe the technical basis of drift-free single-molecule diffusivity measurements in an anti-Brownian electrokinetic trap. We then cross-validate our method with protein-induced fluorescence enhancement, a popular technique to detect protein binding on nucleic acid substrates with single-molecule sensitivity. We extend an existing hydrodynamic modeling framework to link measured diffusivity to particular DNA-protein structures and obtain good agreement between the measured and predicted diffusivity values. Finally, we show that combining diffusivity contrast with protein-induced fluorescence enhancement allows simultaneous mapping of binding stoichiometry and location on individual DNA-protein complexes, potentially enhancing single-molecule views of relevant biophysical processes.
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53
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Yoo J, Lee D, Im H, Ji S, Oh S, Shin M, Park D, Lee G. The mechanism of gap creation by a multifunctional nuclease during base excision repair. SCIENCE ADVANCES 2021; 7:7/29/eabg0076. [PMID: 34261654 PMCID: PMC8279506 DOI: 10.1126/sciadv.abg0076] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 05/28/2021] [Indexed: 05/30/2023]
Abstract
During base excision repair, a transient single-stranded DNA (ssDNA) gap is produced at the apurinic/apyrimidinic (AP) site. Exonuclease III, capable of performing both AP endonuclease and exonuclease activity, are responsible for gap creation in bacteria. We used single-molecule fluorescence resonance energy transfer to examine the mechanism of gap creation. We found an AP site anchor-based mechanism by which the intrinsically distributive enzyme binds strongly to the AP site and becomes a processive enzyme, rapidly creating a gap and an associated transient ssDNA loop. The gap size is determined by the rigidity of the ssDNA loop and the duplex stability of the DNA and is limited to a few nucleotides to maintain genomic stability. When the 3' end is released from the AP endonuclease, polymerase I quickly initiates DNA synthesis and fills the gap. Our work provides previously unidentified insights into how a signal of DNA damage changes the enzymatic functions.
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Affiliation(s)
- Jungmin Yoo
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Single-Molecule Biology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Cell Mechanobiology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Donghun Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Single-Molecule Biology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Cell Mechanobiology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Hyeryeon Im
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Single-Molecule Biology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Sangmi Ji
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Single-Molecule Biology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Sanghoon Oh
- Single-Molecule Biology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-Ro, Jung-gu, Daegu 41944, Korea
| | - Daeho Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Cell Mechanobiology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Gwangrog Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
- Single-Molecule Biology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Cell Mechanobiology Laboratory, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
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54
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Yu H, Bruneau RC, Brennan G, Rothenburg S. Battle Royale: Innate Recognition of Poxviruses and Viral Immune Evasion. Biomedicines 2021; 9:biomedicines9070765. [PMID: 34356829 PMCID: PMC8301327 DOI: 10.3390/biomedicines9070765] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 12/17/2022] Open
Abstract
Host pattern recognition receptors (PRRs) sense pathogen-associated molecular patterns (PAMPs), which are molecular signatures shared by different pathogens. Recognition of PAMPs by PRRs initiate innate immune responses via diverse signaling pathways. Over recent decades, advances in our knowledge of innate immune sensing have enhanced our understanding of the host immune response to poxviruses. Multiple PRR families have been implicated in poxvirus detection, mediating the initiation of signaling cascades, activation of transcription factors, and, ultimately, the expression of antiviral effectors. To counteract the host immune defense, poxviruses have evolved a variety of immunomodulators that have diverse strategies to disrupt or circumvent host antiviral responses triggered by PRRs. These interactions influence the outcomes of poxvirus infections. This review focuses on our current knowledge of the roles of PRRs in the recognition of poxviruses, their elicited antiviral effector functions, and how poxviral immunomodulators antagonize PRR-mediated host immune responses.
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55
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Xing J, Zhou X, Fang M, Zhang E, Minze LJ, Zhang Z. DHX15 is required to control RNA virus-induced intestinal inflammation. Cell Rep 2021; 35:109205. [PMID: 34161762 PMCID: PMC8276442 DOI: 10.1016/j.celrep.2021.109205] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 02/10/2021] [Accepted: 05/11/2021] [Indexed: 02/07/2023] Open
Abstract
RNA helicases play critical roles in various biological processes, including serving as viral RNA sensors in innate immunity. Here, we find that RNA helicase DEAH-box helicase 15 (DHX15) is essential for type I interferon (IFN-I, IFN-β), type III IFN (IFN-λ3), and inflammasome-derived cytokine IL-18 production by intestinal epithelial cells (IECs) in response to poly I:C and RNA viruses with preference of enteric RNA viruses, but not DNA virus. Importantly, we generate IEC-specific Dhx15-knockout mice and demonstrate that DHX15 is required for controlling intestinal inflammation induced by enteric RNA virus rotavirus in suckling mice and reovirus in adult mice in vivo, which owes to impaired IFN-β, IFN-λ3, and IL-18 production in IECs from Dhx15-deficient mice. Mechanistically, DHX15 interacts with NLRP6 to trigger NLRP6 inflammasome assembly and activation for inducing IL-18 secretion in IECs. Collectively, our report reveals critical roles for DHX15 in sensing enteric RNA viruses in IECs and controlling intestinal inflammation.
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Affiliation(s)
- Junji Xing
- Immunobiology and Transplant Science Center, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Xiaojing Zhou
- Immunobiology and Transplant Science Center, Houston Methodist Research Institute, Houston, TX 77030, USA; Department of Biochemistry, Clinical Medical College, Changchun University of Chinese Medicine, Changchun 130117, China
| | - Mingli Fang
- Immunobiology and Transplant Science Center, Houston Methodist Research Institute, Houston, TX 77030, USA; Department of Molecular Biology, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Evan Zhang
- Immunobiology and Transplant Science Center, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Laurie J Minze
- Immunobiology and Transplant Science Center, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Zhiqiang Zhang
- Immunobiology and Transplant Science Center, Houston Methodist Research Institute, Houston, TX 77030, USA; Department of Surgery, Weill Cornell Medical College of Cornell University, New York, NY 10065, USA.
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56
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Li S, Yang J, Zhu Y, Wang H, Ji X, Luo J, Shao Q, Xu Y, Liu X, Zheng W, Meurens F, Chen N, Zhu J. Analysis of Porcine RIG-I Like Receptors Revealed the Positive Regulation of RIG-I and MDA5 by LGP2. Front Immunol 2021; 12:609543. [PMID: 34093517 PMCID: PMC8169967 DOI: 10.3389/fimmu.2021.609543] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 04/07/2021] [Indexed: 12/25/2022] Open
Abstract
The RLRs play critical roles in sensing and fighting viral infections especially RNA virus infections. Despite the extensive studies on RLRs in humans and mice, there is a lack of systemic investigation of livestock animal RLRs. In this study, we characterized the porcine RLR members RIG-I, MDA5 and LGP2. Compared with their human counterparts, porcine RIG-I and MDA5 exhibited similar signaling activity to distinct dsRNA and viruses, via similar and cooperative recognitions. Porcine LGP2, without signaling activity, was found to positively regulate porcine RIG-I and MDA5 in transfected porcine alveolar macrophages (PAMs), gene knockout PAMs and PK-15 cells. Mechanistically, LGP2 interacts with RIG-I and MDA5 upon cell activation, and promotes the binding of dsRNA ligand by MDA5 as well as RIG-I. Accordingly, porcine LGP2 exerted broad antiviral functions. Intriguingly, we found that porcine LGP2 mutants with defects in ATPase and/or dsRNA binding present constitutive activity which are likely through RIG-I and MDA5. Our work provided significant insights into porcine innate immunity, species specificity and immune biology.
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Affiliation(s)
- Shuangjie Li
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Jie Yang
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yuanyuan Zhu
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Hui Wang
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Xingyu Ji
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Jia Luo
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Qi Shao
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Yulin Xu
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Xueliang Liu
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Wanglong Zheng
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - François Meurens
- INRAE, Oniris, BIOEPAR, Nantes, France.,Department of Veterinary Microbiology and Immunology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Nanhua Chen
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Jianzhong Zhu
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China.,College Veterinary Medicine, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
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57
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Sui L, Zhao Y, Wang W, Wu P, Wang Z, Yu Y, Hou Z, Tan G, Liu Q. SARS-CoV-2 Membrane Protein Inhibits Type I Interferon Production Through Ubiquitin-Mediated Degradation of TBK1. Front Immunol 2021; 12:662989. [PMID: 34084167 PMCID: PMC8168463 DOI: 10.3389/fimmu.2021.662989] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/31/2021] [Indexed: 12/25/2022] Open
Abstract
The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative pathogen of current COVID-19 pandemic, and insufficient production of type I interferon (IFN-I) is associated with the severe forms of the disease. Membrane (M) protein of SARS-CoV-2 has been reported to suppress host IFN-I production, but the underlying mechanism is not completely understood. In this study, SARS-CoV-2 M protein was confirmed to suppress the expression of IFNβ and interferon-stimulated genes induced by RIG-I, MDA5, IKKϵ, and TBK1, and to inhibit IRF3 phosphorylation and dimerization caused by TBK1. SARS-CoV-2 M could interact with MDA5, TRAF3, IKKϵ, and TBK1, and induce TBK1 degradation via K48-linked ubiquitination. The reduced TBK1 further impaired the formation of TRAF3-TANK-TBK1-IKKε complex that leads to inhibition of IFN-I production. Our study revealed a novel mechanism of SARS-CoV-2 M for negative regulation of IFN-I production, which would provide deeper insight into the innate immunosuppression and pathogenicity of SARS-CoV-2.
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Affiliation(s)
- Liyan Sui
- Laboratory of Emerging Infectious Disease, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
| | - Yinghua Zhao
- Laboratory of Emerging Infectious Disease, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
| | - Wenfang Wang
- College of Basic Medical Science, Jilin University, Changchun, China
| | - Ping Wu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Zedong Wang
- Laboratory of Emerging Infectious Disease, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
| | - Yang Yu
- Hospital of Stomatology, Jilin University, Changchun, China
| | - Zhijun Hou
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Guangyun Tan
- Department of Immunology, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
| | - Quan Liu
- Laboratory of Emerging Infectious Disease, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
- School of Life Sciences and Engineering, Foshan University, Foshan, China
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58
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Gazquez-Gutierrez A, Witteveldt J, R Heras S, Macias S. Sensing of transposable elements by the antiviral innate immune system. RNA (NEW YORK, N.Y.) 2021; 27:rna.078721.121. [PMID: 33888553 PMCID: PMC8208052 DOI: 10.1261/rna.078721.121] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/17/2021] [Indexed: 05/15/2023]
Abstract
Around half of the genome in mammals is composed of transposable elements (TEs) such as DNA transposons and retrotransposons. Several mechanisms have evolved to prevent their activity and the detrimental impact of their insertional mutagenesis. Despite these potentially negative effects, TEs are essential drivers of evolution, and in certain settings, beneficial to their hosts. For instance, TEs have rewired the antiviral gene regulatory network and are required for early embryonic development. However, due to structural similarities between TE-derived and viral nucleic acids, cells can misidentify TEs as invading viruses and trigger the major antiviral innate immune pathway, the type I interferon (IFN) response. This review will focus on the different settings in which the role of TE-mediated IFN activation has been documented, including cancer and senescence. Importantly, TEs may also play a causative role in the development of complex autoimmune diseases characterised by constitutive type I IFN activation. All these observations suggest the presence of strong but opposing forces driving the coevolution of TEs and antiviral defence. A better biological understanding of the TE replicative cycle as well as of the antiviral nucleic acid sensing mechanisms will provide insights into how these two biological processes interact and will help to design better strategies to treat human diseases characterised by aberrant TE expression and/or type I IFN activation.
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Affiliation(s)
| | - Jeroen Witteveldt
- University of Edinburgh - Institute of Immunology and Infection Research
| | - Sara R Heras
- GENYO. Centre for Genomics and Oncological Research, Pfizer University of Granada
| | - Sara Macias
- Institute of Immunology and Infection Research
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59
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Singh RK, Jonely M, Leslie E, Rejali NA, Noriega R, Bass BL. Transient kinetic studies of the antiviral Drosophila Dicer-2 reveal roles of ATP in self-nonself discrimination. eLife 2021; 10:65810. [PMID: 33787495 PMCID: PMC8079148 DOI: 10.7554/elife.65810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/31/2021] [Indexed: 11/25/2022] Open
Abstract
Some RIG-I-like receptors (RLRs) discriminate viral and cellular dsRNA by their termini, and Drosophila melanogaster Dicer-2 (dmDcr-2) differentially processes dsRNA with blunt or 2 nucleotide 3’-overhanging termini. We investigated the transient kinetic mechanism of the dmDcr-2 reaction using a rapid reaction stopped-flow technique and time-resolved fluorescence spectroscopy. Indeed, we found that ATP binding to dmDcr-2’s helicase domain impacts association and dissociation kinetics of dsRNA in a termini-dependent manner, revealing termini-dependent discrimination of dsRNA on a biologically relevant time scale (seconds). ATP hydrolysis promotes transient unwinding of dsRNA termini followed by slow rewinding, and directional translocation of the enzyme to the cleavage site. Time-resolved fluorescence anisotropy reveals a nucleotide-dependent modulation in conformational fluctuations (nanoseconds) of the helicase and Platform–PAZ domains that is correlated with termini-dependent dsRNA cleavage. Our study offers a kinetic framework for comparison to other Dicers, as well as all members of the RLRs involved in innate immunity.
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Affiliation(s)
- Raushan K Singh
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - McKenzie Jonely
- Department of Chemistry, University of Utah, Salt Lake City, United States
| | - Evan Leslie
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Nick A Rejali
- Department of Pathology, University of Utah, Salt Lake City, United States
| | - Rodrigo Noriega
- Department of Chemistry, University of Utah, Salt Lake City, United States
| | - Brenda L Bass
- Department of Biochemistry, University of Utah, Salt Lake City, United States
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60
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Huang H, Zhao J, Wang TY, Zhang S, Zhou Y, Rao Y, Qin C, Liu Y, Chen Y, Xia Z, Feng P. Species-Specific Deamidation of RIG-I Reveals Collaborative Action between Viral and Cellular Deamidases in HSV-1 Lytic Replication. mBio 2021; 12:e00115-21. [PMID: 33785613 PMCID: PMC8092204 DOI: 10.1128/mbio.00115-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/23/2021] [Indexed: 12/17/2022] Open
Abstract
Retinoic acid-inducible gene I (RIG-I) is a sensor that recognizes cytosolic double-stranded RNA derived from microbes to induce host immune response. Viruses, such as herpesviruses, deploy diverse mechanisms to derail RIG-I-dependent innate immune defense. In this study, we discovered that mouse RIG-I is intrinsically resistant to deamidation and evasion by herpes simplex virus 1 (HSV-1). Comparative studies involving human and mouse RIG-I indicate that N495 of human RIG-I dictates species-specific deamidation by HSV-1 UL37. Remarkably, deamidation of the other site, N549, hinges on that of N495, and it is catalyzed by cellular phosphoribosylpyrophosphate amidotransferase (PPAT). Specifically, deamidation of N495 enables RIG-I to interact with PPAT, leading to subsequent deamidation of N549. Collaboration between UL37 and PPAT is required for HSV-1 to evade RIG-I-mediated antiviral immune response. This work identifies an immune regulatory role of PPAT in innate host defense and establishes a sequential deamidation event catalyzed by distinct deamidases in immune evasion.IMPORTANCE Herpesviruses are ubiquitous pathogens in human and establish lifelong persistence despite host immunity. The ability to evade host immune response is pivotal for viral persistence and pathogenesis. In this study, we investigated the evasion, mediated by deamidation, of species-specific RIG-I by herpes simplex virus 1 (HSV-1). Our findings uncovered a collaborative and sequential action between viral deamidase UL37 and a cellular glutamine amidotransferase, phosphoribosylpyrophosphate amidotransferase (PPAT), to inactivate RIG-I and mute antiviral gene expression. PPAT catalyzes the rate-limiting step of the de novo purine synthesis pathway. This work describes a new function of cellular metabolic enzymes in host defense and viral immune evasion.
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Affiliation(s)
- Huichao Huang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics, XiangYa Hospital, Central South University, Changsha, Hunan, China
| | - Jun Zhao
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
| | - Ting-Yu Wang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
| | - Shu Zhang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
| | - Yuzheng Zhou
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
- Department of Cell Biology, Hunan Key Laboratory of Animal Models for Human Diseases, Hunan Key Laboratory of Medical Genetics and Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Youliang Rao
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
| | - Chao Qin
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
| | - Yongzhen Liu
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
| | - Yongheng Chen
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics, XiangYa Hospital, Central South University, Changsha, Hunan, China
| | - Zanxian Xia
- Department of Cell Biology, Hunan Key Laboratory of Animal Models for Human Diseases, Hunan Key Laboratory of Medical Genetics and Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Pinghui Feng
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA
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61
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Onomoto K, Onoguchi K, Yoneyama M. Regulation of RIG-I-like receptor-mediated signaling: interaction between host and viral factors. Cell Mol Immunol 2021; 18:539-555. [PMID: 33462384 PMCID: PMC7812568 DOI: 10.1038/s41423-020-00602-7] [Citation(s) in RCA: 243] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/17/2020] [Indexed: 01/31/2023] Open
Abstract
Retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) are RNA sensor molecules that play essential roles in innate antiviral immunity. Among the three RLRs encoded by the human genome, RIG-I and melanoma differentiation-associated gene 5, which contain N-terminal caspase recruitment domains, are activated upon the detection of viral RNAs in the cytoplasm of virus-infected cells. Activated RLRs induce downstream signaling via their interactions with mitochondrial antiviral signaling proteins and activate the production of type I and III interferons and inflammatory cytokines. Recent studies have shown that RLR-mediated signaling is regulated by interactions with endogenous RNAs and host proteins, such as those involved in stress responses and posttranslational modifications. Since RLR-mediated cytokine production is also involved in the regulation of acquired immunity, the deregulation of RLR-mediated signaling is associated with autoimmune and autoinflammatory disorders. Moreover, RLR-mediated signaling might be involved in the aberrant cytokine production observed in coronavirus disease 2019. Since the discovery of RLRs in 2004, significant progress has been made in understanding the mechanisms underlying the activation and regulation of RLR-mediated signaling pathways. Here, we review the recent advances in the understanding of regulated RNA recognition and signal activation by RLRs, focusing on the interactions between various host and viral factors.
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Affiliation(s)
- Koji Onomoto
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8673, Japan
| | - Kazuhide Onoguchi
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8673, Japan
| | - Mitsutoshi Yoneyama
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8673, Japan.
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Application of Advanced Light Microscopy to the Study of HIV and Its Interactions with the Host. Viruses 2021; 13:v13020223. [PMID: 33535486 PMCID: PMC7912744 DOI: 10.3390/v13020223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/24/2022] Open
Abstract
This review highlights the significant observations of human immunodeficiency virus (HIV) assembly, release and maturation made possible with advanced light microscopy techniques. The advances in technology which now enables these light microscopy measurements are discussed with special emphasis on live imaging approaches including Total Internal Reflection Fluorescence (TIRF), high-resolution light microscopy techniques including PALM and STORM and single molecule measurements, including Fluorescence Resonance Energy Transfer (FRET). The review concludes with a discussion on what new insights and understanding can be expected from these measurements.
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63
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Khan MI, Nur SM, Adhami V, Mukhtar H. Epigenetic regulation of RNA sensors: Sentinels of immune response. Semin Cancer Biol 2021; 83:413-421. [PMID: 33484869 DOI: 10.1016/j.semcancer.2020.12.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/11/2022]
Abstract
Living host system possess mechanisms like innate immune system to combat against inflammation, stress singling, and cancer. These mechanisms are initiated by PAMP and DAMP mediated recognition by PRR. PRR is consist of variety of nucleic acid sensors like-RNA sensors. They play crucial role in identifying exogenous and endogenous RNA molecules, which subsequently mediate pro/inflammatory cytokine, IFN and ISGs response in traumatized or tumorigenic conditions. The sensors can sensitize wide range of nucleic acid particle in term of size and structure, while each category sensors belongs subclasses with differentially expressed in cell and distinguished functioning mechanisms. They are also able to make comparison between self and non-self-nucleic acid molecules through specific mechanisms. Besides exhibiting anti-inflammatory and anti-tumorigenic responses, RNA sensors cover the broad spectrum of response mechanisms. Transcriptionally RNA sensors undergo with tight epigenetic regulations. In this review study, we will be going to discuss about the details of RNA sensors, their functional mechanisms and epi-transactional regulations.
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Affiliation(s)
- Mohammad Imran Khan
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Suza Mohammad Nur
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Vaqar Adhami
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, USA
| | - Hasan Mukhtar
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, USA.
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64
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The influenza virus RNA polymerase as an innate immune agonist and antagonist. Cell Mol Life Sci 2021; 78:7237-7256. [PMID: 34677644 PMCID: PMC8532088 DOI: 10.1007/s00018-021-03957-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/16/2021] [Accepted: 09/29/2021] [Indexed: 12/16/2022]
Abstract
Influenza A viruses cause a mild-to-severe respiratory disease that affects millions of people each year. One of the many determinants of disease outcome is the innate immune response to the viral infection. While antiviral responses are essential for viral clearance, excessive innate immune activation promotes lung damage and disease. The influenza A virus RNA polymerase is one of viral proteins that affect innate immune activation during infection, but the mechanisms behind this activity are not well understood. In this review, we discuss how the viral RNA polymerase can both activate and suppress innate immune responses by either producing immunostimulatory RNA species or directly targeting the components of the innate immune signalling pathway, respectively. Furthermore, we provide a comprehensive overview of the polymerase residues, and their mutations, associated with changes in innate immune activation, and discuss their putative effects on polymerase function based on recent advances in our understanding of the influenza A virus RNA polymerase structure.
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65
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Cho J, Oh S, Lee D, Han JW, Yoo J, Park D, Lee G. Spectroscopic sensing and quantification of AP-endonucleases using fluorescence-enhancement by cis– trans isomerization of cyanine dyes. RSC Adv 2021; 11:11380-11386. [PMID: 35423644 PMCID: PMC8695990 DOI: 10.1039/d0ra08051a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/08/2021] [Indexed: 11/21/2022] Open
Abstract
Apurinic/apyrimidinic (AP) endonucleases are vital DNA repair enzymes, and proposed to be a prognostic biomarker for various types of cancer in humans. Numerous DNA sensors have been developed to evaluate the extent of nuclease activity but their DNA termini are not protected against other nucleases, hampering accurate quantification. Here we developed a new fluorescence enhancement (FE)-based method as an enzyme-specific DNA biosensor with nuclease-protection by three functional units (an AP-site, Cy3 and termini that are protected from exonucleolytic cleavage). A robust FE signal arises from the fluorescent cis–trans isomerization of a cyanine dye (e.g., Cy3) upon the enzyme-triggered structural change from double-stranded (ds)DNA to single-stranded (ss)DNA that carries Cy3. The FE-based assay reveals a linear dependency on sub-nanomolar concentrations as low as 10−11 M for the target enzyme and can be also utilized as a sensitive readout of other nuclease activities. Apurinic/apyrimidinic (AP) endonucleases are vital DNA repair enzymes, and proposed to be a prognostic biomarker for various types of cancer in humans.![]()
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Affiliation(s)
- JunHo Cho
- School of Life Sciences
- Gwangju Institute of Science and Technology
- Gwangju
- Korea
| | - Sanghoon Oh
- Department of Biomedical Science and Engineering
- Gwangju Institute of Science and Technology
- Gwangju
- Korea
| | - DongHun Lee
- School of Life Sciences
- Gwangju Institute of Science and Technology
- Gwangju
- Korea
| | - Jae Won Han
- School of Life Sciences
- Gwangju Institute of Science and Technology
- Gwangju
- Korea
| | - Jungmin Yoo
- School of Life Sciences
- Gwangju Institute of Science and Technology
- Gwangju
- Korea
| | - Daeho Park
- School of Life Sciences
- Gwangju Institute of Science and Technology
- Gwangju
- Korea
- Cell Mechanobiology Research Center
| | - Gwangrog Lee
- School of Life Sciences
- Gwangju Institute of Science and Technology
- Gwangju
- Korea
- Department of Biomedical Science and Engineering
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66
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In vitro production of synthetic viral RNAs and their delivery into mammalian cells and the application of viral RNAs in the study of innate interferon responses. Methods 2020; 183:21-29. [PMID: 31682923 DOI: 10.1016/j.ymeth.2019.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/25/2019] [Accepted: 10/30/2019] [Indexed: 12/24/2022] Open
Abstract
Mammalian cells express different types of RNA molecules that can be classified as protein coding RNAs (mRNA) and non-coding RNAs (ncRNAs) the latter of which have housekeeping and regulatory functions in cells. Cellular RNAs are not recognized by cellular pattern recognition receptors (PRRs) and innate immunity is not activated. RNA viruses encode and express RNA molecules that usually differ from cell-specific RNAs and they include for instance 5'capped and 5'mono- and triphosphorylated RNAs, small viral RNAs and viral RNA-protein complexes called vRNPs. These molecules are recognized by certain members of Toll-like receptor (TLR) and RIG-I-like receptor (RLR) families leading to activation of innate immune responses and the production of antiviral cytokines, such as type I and type III interferons (IFNs). Virus-specific ssRNA and dsRNA molecules that mimic the viral genomic RNAs or their replication intermediates can efficiently be produced by bacteriophage T7 DNA-dependent RNA polymerase and bacteriophage phi6 RNA-dependent RNA polymerase, respectively. These molecules can then be delivered into mammalian cells and the mechanisms of activation of innate immune responses can be studied. In addition, synthetic viral dsRNAs can be processed to small interfering RNAs (siRNAs) by a Dicer enzyme to produce a swarm of antiviral siRNAs. Here we describe the biology of RNAs, their in vitro production and delivery into mammalian cells as well as how these molecules can be used to inhibit virus replication and to study the mechanisms of activation of the innate immune system.
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67
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Lim Y, Bak SY, Lee SH, Kim SK. Comparative Single-Molecule Kinetic Study for the Effect of Base Methylation on a Model DNA-Protein Interaction. J Phys Chem Lett 2020; 11:8048-8052. [PMID: 32885977 DOI: 10.1021/acs.jpclett.0c01929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We studied how the interaction between HindIII endonuclease and dsDNA is affected by the single-base modification of the latter by a single-molecule kinetic assay. For a comparative study of chemical modifications, we measured the binding and unbinding rates of the HindIII-DNA complex for normal dsDNA, methylated DNA, and hydroxymethylated DNA. We found that methylation of DNA at the recognition site results in a large increase in the unbinding rate due to the steric effect, which is consistent with the standard free energy change in the transition state. On the contrary, methylation minimally affects the binding rate, as simultaneous increases in the activation energy and the pre-exponential factor compensate for each other.
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Affiliation(s)
- Youngbin Lim
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - So Young Bak
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Sang Hak Lee
- Department of Chemistry, Pusan National University, Pusan 46241, Korea
| | - Seong Keun Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
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68
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Stok JE, Vega Quiroz ME, van der Veen AG. Self RNA Sensing by RIG-I–like Receptors in Viral Infection and Sterile Inflammation. THE JOURNAL OF IMMUNOLOGY 2020; 205:883-891. [DOI: 10.4049/jimmunol.2000488] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/28/2020] [Indexed: 12/18/2022]
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69
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Purification and Characterization of Double-Stranded Nucleic Acid-Dependent ATPase Activities of Tagged Dicer-Related Helicase 1 and its Short Isoform in Caenorhabditis elegans. Genes (Basel) 2020; 11:genes11070734. [PMID: 32630243 PMCID: PMC7397212 DOI: 10.3390/genes11070734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/25/2020] [Accepted: 06/30/2020] [Indexed: 02/08/2023] Open
Abstract
The Dicer-related helicases (DRHs) are members of a helicase subfamily, and mammalian DRHs such as retinoic acid-inducible gene-I (RIG-I), are involved in antiviral immunity. Caenorhabditis elegans DRH-1 and DRH-3 play crucial roles in antiviral function and chromosome segregation, respectively. Although intrinsic double-stranded RNA-dependent ATP-hydrolyzing activity has been observed in the recombinant DRH-3 protein prepared from Escherichia coli, there are no reports of biochemical studies of the nematode RIG-I homolog DRH-1. In this study, the secondary structure prediction by JPred4 revealed that DRH-1 and DRH-3 had distinct N-terminal regions and that a 200-amino acid N-terminal region of DRH-1 could form a structure very rich in α-helices. We investigated expressions and purifications of a codon-optimized DRH-1 with four different N-terminal tags, identifying poly-histidine (His)-small ubiquitin-like modifier (SUMO) as a suitable tag for DRH-1 preparation. Full-length (isoform a) and a N-terminal truncated (isoform b) of DRH-1 were purified as the His-SUMO-tagged fusion proteins. Finally, the nucleic acid-dependent ATPase activities were investigated for the two His-SUMO-tagged DRH-1 isoforms and His-tagged DRH-3. The tagged DRH-3 exhibited dsRNA-dependent ATPase activity. However, detectable dsRNA dependency of ATPase activities was not found in either isoform of tagged DRH-1 and a tag-free DRH-1 (isoform a) treated with SUMO protease. These observations suggest that DRH-1 and its short isoform have no or poor nucleic acid-dependent ATPase activity, unlike DRH-3 and mammalian DRHs.
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70
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Schweinoch D, Bachmann P, Clausznitzer D, Binder M, Kaderali L. Mechanistic modeling explains the dsRNA length-dependent activation of the RIG-I mediated immune response. J Theor Biol 2020; 500:110336. [PMID: 32446742 DOI: 10.1016/j.jtbi.2020.110336] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 12/25/2022]
Abstract
In cell-intrinsic antiviral immunity, cytoplasmic receptors such as retinoic acid-inducible gene I (RIG-I) detect viral double-stranded RNA (dsRNA) and trigger a signaling cascade activating the interferon (IFN) system. This leads to the transcription of hundreds of interferon-stimulated genes (ISGs) with a wide range of antiviral effects. This recognition of dsRNA not only has to be very specific to discriminate foreign from self but also highly sensitive to detect even very low numbers of pathogenic dsRNA molecules. Previous work indicated an influence of the dsRNA length on the binding behavior of RIG-I and its potential to elicit antiviral signaling. However, the molecular mechanisms behind the binding process are still under debate. We compare two hypothesized RIG-I binding mechanisms by translating them into mathematical models and analyzing their potential to describe published experimental data. The models consider the length of the dsRNA as well as known RIG-I binding motifs and describe RIG-I pathway activation after stimulation with dsRNA. We show that internal RIG-I binding sites in addition to cooperative RIG-I oligomerization are essential to describe the experimentally observed RIG-I binding behavior and immune response activation for different dsRNA lengths and concentrations. The combination of RIG-I binding to internal sites on the dsRNA and cooperative oligomerization compensates for a lack of high-affinity binding motifs and triggers a strong antiviral response for long dsRNAs. Model analysis reveals dsRNA length-dependency as a potential mechanism to discriminate between different types of dsRNAs: It allows for sensitive detection of small numbers of long dsRNAs, a typical by-product of viral replication, while ensuring tolerance against non-harming small dsRNAs.
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Affiliation(s)
- Darius Schweinoch
- University Medicine Greifswald, Institute of Bioinformatics and Center for Functional Genomics of Microbes (C_FunGene), Felix-Hausdorff-Str. 8, 17475 Greifswald, Germany
| | - Pia Bachmann
- University Medicine Greifswald, Institute of Bioinformatics and Center for Functional Genomics of Microbes (C_FunGene), Felix-Hausdorff-Str. 8, 17475 Greifswald, Germany
| | - Diana Clausznitzer
- Technische Universität Dresden, Faculty of Medicine Carl-Gustav Carus, Institute for Medical Informatics and Biometry, Dresden, Germany
| | - Marco Binder
- Research Group "Dynamics of Early Viral Infection and the Innate Antiviral Response", Division Virus-Associated Carcinogenesis (F170), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Lars Kaderali
- University Medicine Greifswald, Institute of Bioinformatics and Center for Functional Genomics of Microbes (C_FunGene), Felix-Hausdorff-Str. 8, 17475 Greifswald, Germany.
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71
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Lu M, Zhang Z, Xue M, Zhao BS, Harder O, Li A, Liang X, Gao TZ, Xu Y, Zhou J, Feng Z, Niewiesk S, Peeples ME, He C, Li J. N 6-methyladenosine modification enables viral RNA to escape recognition by RNA sensor RIG-I. Nat Microbiol 2020; 5:584-598. [PMID: 32015498 PMCID: PMC7137398 DOI: 10.1038/s41564-019-0653-9] [Citation(s) in RCA: 184] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 12/03/2019] [Indexed: 12/18/2022]
Abstract
Internal N6-methyladenosine (m6A) modification is one of the most common and abundant modifications of RNA. However, the biological roles of viral RNA m6A remain elusive. Here, using human metapneumovirus (HMPV) as a model, we demonstrate that m6A serves as a molecular marker for innate immune discrimination of self from non-self RNAs. We show that HMPV RNAs are m6A methylated and that viral m6A methylation promotes HMPV replication and gene expression. Inactivating m6A addition sites with synonymous mutations or demethylase resulted in m6A-deficient recombinant HMPVs and virion RNAs that induced increased expression of type I interferon, which was dependent on the cytoplasmic RNA sensor RIG-I, and not on melanoma differentiation-associated protein 5 (MDA5). Mechanistically, m6A-deficient virion RNA induces higher expression of RIG-I, binds more efficiently to RIG-I and facilitates the conformational change of RIG-I, leading to enhanced interferon expression. Furthermore, m6A-deficient recombinant HMPVs triggered increased interferon in vivo and were attenuated in cotton rats but retained high immunogenicity. Collectively, our results highlight that (1) viruses acquire m6A in their RNA as a means of mimicking cellular RNA to avoid detection by innate immunity and (2) viral RNA m6A can serve as a target to attenuate HMPV for vaccine purposes.
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Affiliation(s)
- Mijia Lu
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Zijie Zhang
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Miaoge Xue
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Boxuan Simen Zhao
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Olivia Harder
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Anzhong Li
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Xueya Liang
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Thomas Z Gao
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Yunsheng Xu
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jiyong Zhou
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Zongdi Feng
- Center for Vaccines and Immunity, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Stefan Niewiesk
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Mark E Peeples
- Center for Vaccines and Immunity, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Chuan He
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Jianrong Li
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA.
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Choudhury NR, Heikel G, Michlewski G. TRIM25 and its emerging RNA-binding roles in antiviral defense. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1588. [PMID: 31990130 DOI: 10.1002/wrna.1588] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/25/2022]
Abstract
The innate immune system is the body's first line of defense against viruses, with pattern recognition receptors (PRRs) recognizing molecules unique to viruses and triggering the expression of interferons and other anti-viral cytokines, leading to the formation of an anti-viral state. The tripartite motif containing 25 (TRIM25) is an E3 ubiquitin ligase thought to be a key component in the activation of signaling by the PRR retinoic acid-inducible gene I protein (RIG-I). TRIM25 has recently been identified as an RNA-binding protein, raising the question of whether its RNA-binding activity is important for its role in innate immunity. Here, we review TRIM25's mechanisms and pathways in noninfected and infected cells. We also introduce models that explain how TRIM25 binding to RNA could modulate its functions and play part in the antiviral response. These findings have opened new lines of investigations into functional and molecular roles of TRIM25 and other E3 ubiquitin ligases in cell biology and control of pathogenic infections. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.
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Affiliation(s)
| | - Gregory Heikel
- Infection Medicine, University of Edinburgh, Edinburgh, UK
| | - Gracjan Michlewski
- Infection Medicine, University of Edinburgh, Edinburgh, UK.,Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Zhejiang University, Zhejiang, People's Republic of China
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73
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Avian Pattern Recognition Receptor Sensing and Signaling. Vet Sci 2020; 7:vetsci7010014. [PMID: 32012730 PMCID: PMC7157566 DOI: 10.3390/vetsci7010014] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 01/16/2020] [Accepted: 01/23/2020] [Indexed: 02/07/2023] Open
Abstract
Pattern recognition receptors (PRRs) are a class of immune sensors that play a critical role in detecting and responding to several conserved patterns of microorganisms. As such, they play a major role in the maintenance of immune homeostasis and anti-microbial defense. Fundamental knowledge pertaining to the discovery of PRR functions and their ligands continue to advance the understanding of immune system and disease resistance, which led to the rational design and/or application of various PRR ligands as vaccine adjuvants. In addition, the conserved nature of many PRRs throughout the animal kingdom has enabled the utilization of the comparative genomics approach in PRR identification and the study of evolution, structural features, and functions in many animal species including avian. In the present review, we focused on PRR sensing and signaling functions in the avian species, domestic chicken, mallard, and domestic goose. In addition to summarizing recent advances in the understanding of avian PRR functions, the present review utilized a comparative biology approach to identify additional PRRs, whose functions have been well studied in mammalians but await functional characterization in avian.
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74
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Branched unwinding mechanism of the Pif1 family of DNA helicases. Proc Natl Acad Sci U S A 2019; 116:24533-24541. [PMID: 31744872 DOI: 10.1073/pnas.1915654116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Members of the Pif1 family of helicases function in multiple pathways that involve DNA synthesis: DNA replication across G-quadruplexes; break-induced replication; and processing of long flaps during Okazaki fragment maturation. Furthermore, Pif1 increases strand-displacement DNA synthesis by DNA polymerase δ and allows DNA replication across arrays of proteins tightly bound to DNA. This is a surprising feat since DNA rewinding or annealing activities limit the amount of single-stranded DNA product that Pif1 can generate, leading to an apparently poorly processive helicase. In this work, using single-molecule Förster resonance energy transfer approaches, we show that 2 members of the Pif1 family of helicases, Pif1 from Saccharomyces cerevisiae and Pfh1 from Schizosaccharomyces pombe, unwind double-stranded DNA by a branched mechanism with 2 modes of activity. In the dominant mode, only short stretches of DNA can be processively and repetitively opened, with reclosure of the DNA occurring by mechanisms other than strand-switching. In the other less frequent mode, longer stretches of DNA are unwound via a path that is separate from the one leading to repetitive unwinding. Analysis of the kinetic partitioning between the 2 different modes suggests that the branching point in the mechanism is established by conformational selection, controlled by the interaction of the helicase with the 3' nontranslocating strand. The data suggest that the dominant and repetitive mode of DNA opening of the helicase can be used to allow efficient DNA replication, with DNA synthesis on the nontranslocating strand rectifying the DNA unwinding activity.
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75
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Kumari N, Ciuba MA, Levitus M. Photophysical properties of the hemicyanine Dy-630 and its potential as a single-molecule fluorescent probe for biophysical applications. Methods Appl Fluoresc 2019; 8:015004. [PMID: 31585443 DOI: 10.1088/2050-6120/ab4b0d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Protein-induced fluorescence enhancement (PIFE) is an increasingly used approach to investigate DNA-protein interactions at the single molecule level. The optimal probe for this type of application is highly photostable, has a high absorption extinction coefficient, and has a moderate fluorescence quantum yield that increases significantly when the dye is in close proximity to a large macromolecule such as a protein. So far, the green-absorbing symmetric cyanine known as Cy3 has been the probe of choice in this field because the magnitude of the increase observed upon protein binding (usually 2-4 -fold) is large enough to allow for the analysis of protein dynamics on the inherently noisy single-molecule signals. Here, we report the characterization of the photophysical properties of the red-absorbing hemicyanine dye Dy-630 in the context of its potential application as a single-molecule PIFE probe. The behavior of Dy-630 in solution is similar to that of Cy3; the fluorescence quantum yield and lifetime of Dy-630 increase with increasing viscosity, and decrease with increasing temperature indicating the existence of an activated nonradiative process that depopulates the singlet state of the dye. As in the case of Cy3, the results of transient spectroscopy experiments are consistent with the formation of a photoisomer that reverts to the ground state thermally in the microsecond timescale. Unfortunately, experiments with DNA samples paint a more complex scenario. As in the case of Cy3, the fluorescence quantum yield of Dy-630 increases significantly when the dye interacts with the DNA bases, but in the case of Dy-630 attachment to DNA results in an already long fluorescence lifetime that does not provide a significant window for the protein-induced enhancement observed with Cy3. Although we show that Dy-630 may not be well-suited for PIFE, our results shed light on the optimal design principles for probes for PIFE applications.
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76
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Cadena C, Hur S. Filament-like Assemblies of Intracellular Nucleic Acid Sensors: Commonalities and Differences. Mol Cell 2019; 76:243-254. [PMID: 31626748 PMCID: PMC6880955 DOI: 10.1016/j.molcel.2019.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/13/2019] [Accepted: 09/19/2019] [Indexed: 12/25/2022]
Abstract
Self versus non-self discrimination by innate immune sensors is critical for mounting effective immune responses against pathogens while avoiding harmful auto-inflammatory reactions against the host. Foreign DNA and RNA sensors must discriminate between self versus non-self nucleic acids, despite their shared building blocks and similar physicochemical properties. Recent structural and biochemical studies suggest that multiple steps of filament-like assembly are required for the functions of several nucleic acid sensors. Here, we discuss ligand discrimination and oligomerization of RIG-I-like receptors, AIM2-like receptors, and cGAS. We discuss how filament-like assembly allows for robust and accurate discrimination of self versus non-self nucleic acids and how these assemblies enable sensing of multiple distinct features in foreign nucleic acids, including structure, length, and modifications. We also discuss how individual receptors differ in their assembly and disassembly mechanisms and how these differences contribute to the diversity in nucleic acid specificity and pathogen detection strategies.
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Affiliation(s)
- Cristhian Cadena
- Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Sun Hur
- Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA.
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77
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Dickey TH, Song B, Pyle AM. RNA binding activates RIG-I by releasing an autorepressed signaling domain. SCIENCE ADVANCES 2019; 5:eaax3641. [PMID: 31616790 PMCID: PMC6774723 DOI: 10.1126/sciadv.aax3641] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
The retinoic acid-inducible gene I (RIG-I) innate immune receptor is an important immunotherapeutic target, but we lack approaches for monitoring the physical basis for its activation in vitro. This gap in our understanding has led to confusion about mechanisms of RIG-I activation and difficulty discovering agonists and antagonists. We therefore created a novel fluorescence resonance energy transfer-based method for measuring RIG-I activation in vitro using dual site-specific fluorescent labeling of the protein. This approach enables us to measure the conformational change that releases the signaling domain during the first step of RIG-I activation, making it possible to understand the role of stimulatory ligands. We have found that RNA alone is sufficient to eject the signaling domain, ejection is reversible, and adenosine triphosphate plays but a minor role in this process. These findings help explain RIG-I dysfunction in autoimmune disease, and they inform the design of therapeutics targeting RIG-I.
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Affiliation(s)
- T. H. Dickey
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - B. Song
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - A. M. Pyle
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
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78
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Brisse M, Ly H. Comparative Structure and Function Analysis of the RIG-I-Like Receptors: RIG-I and MDA5. Front Immunol 2019; 10:1586. [PMID: 31379819 PMCID: PMC6652118 DOI: 10.3389/fimmu.2019.01586] [Citation(s) in RCA: 249] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/25/2019] [Indexed: 12/12/2022] Open
Abstract
RIG-I (Retinoic acid-inducible gene I) and MDA5 (Melanoma Differentiation-Associated protein 5), collectively known as the RIG-I-like receptors (RLRs), are key protein sensors of the pathogen-associated molecular patterns (PAMPs) in the form of viral double-stranded RNA (dsRNA) motifs to induce expression of type 1 interferons (IFN1) (IFNα and IFNβ) and other pro-inflammatory cytokines during the early stage of viral infection. While RIG-I and MDA5 share many genetic, structural and functional similarities, there is increasing evidence that they can have significantly different strategies to recognize different pathogens, PAMPs, and in different host species. This review article discusses the similarities and differences between RIG-I and MDA5 from multiple perspectives, including their structures, evolution and functional relationships with other cellular proteins, their differential mechanisms of distinguishing between host and viral dsRNAs and interactions with host and viral protein factors, and their immunogenic signaling. A comprehensive comparative analysis can help inform future studies of RIG-I and MDA5 in order to fully understand their functions in order to optimize potential therapeutic approaches targeting them.
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Affiliation(s)
- Morgan Brisse
- Biochemistry, Molecular Biology, and Biophysics Graduate Program, University of Minnesota, Twin Cities, St. Paul, MN, United States
- Department of Veterinary & Biomedical Sciences, University of Minnesota, Twin Cities, St. Paul, MN, United States
| | - Hinh Ly
- Department of Veterinary & Biomedical Sciences, University of Minnesota, Twin Cities, St. Paul, MN, United States
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79
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Protein Environment and DNA Orientation Affect Protein-Induced Cy3 Fluorescence Enhancement. Biophys J 2019; 117:66-73. [PMID: 31235181 DOI: 10.1016/j.bpj.2019.05.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/23/2019] [Accepted: 05/29/2019] [Indexed: 11/20/2022] Open
Abstract
The cyanine dye Cy3 is a popular fluorophore used to probe the binding of proteins to nucleic acids as well as their conformational transitions. Nucleic acids labeled only with Cy3 can often be used to monitor interactions with unlabeled proteins because of an enhancement of Cy3 fluorescence intensity that results when the protein contacts Cy3, a property sometimes referred to as protein-induced fluorescence enhancement (PIFE). Although Cy3 fluorescence is enhanced upon contacting most proteins, we show here in studies of human replication protein A and Escherichia coli single-stranded DNA binding protein that the magnitude of the Cy3 enhancement is dependent on both the protein as well as the orientation of the protein with respect to the Cy3 label on the DNA. This difference in PIFE is due entirely to differences in the final protein-DNA complex. We also show that the origin of PIFE is the longer fluorescence lifetime induced by the local protein environment. These results indicate that PIFE is not a through space distance-dependent phenomenon but requires a direct interaction of Cy3 with the protein, and the magnitude of the effect is influenced by the region of the protein contacting Cy3. Hence, use of the Cy3 PIFE effect for quantitative studies may require careful calibration.
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80
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Cadena C, Ahmad S, Xavier A, Willemsen J, Park S, Park JW, Oh SW, Fujita T, Hou F, Binder M, Hur S. Ubiquitin-Dependent and -Independent Roles of E3 Ligase RIPLET in Innate Immunity. Cell 2019; 177:1187-1200.e16. [PMID: 31006531 PMCID: PMC6525047 DOI: 10.1016/j.cell.2019.03.017] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/28/2019] [Accepted: 03/07/2019] [Indexed: 01/22/2023]
Abstract
The conventional view posits that E3 ligases function primarily through conjugating ubiquitin (Ub) to their substrate molecules. We report here that RIPLET, an essential E3 ligase in antiviral immunity, promotes the antiviral signaling activity of the viral RNA receptor RIG-I through both Ub-dependent and -independent manners. RIPLET uses its dimeric structure and a bivalent binding mode to preferentially recognize and ubiquitinate RIG-I pre-oligomerized on dsRNA. In addition, RIPLET can cross-bridge RIG-I filaments on longer dsRNAs, inducing aggregate-like RIG-I assemblies. The consequent receptor clustering synergizes with the Ub-dependent mechanism to amplify RIG-I-mediated antiviral signaling in an RNA-length dependent manner. These observations show the unexpected role of an E3 ligase as a co-receptor that directly participates in receptor oligomerization and ligand discrimination. It also highlights a previously unrecognized mechanism by which the innate immune system measures foreign nucleic acid length, a common criterion for self versus non-self nucleic acid discrimination.
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Affiliation(s)
- Cristhian Cadena
- Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Sadeem Ahmad
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Audrey Xavier
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA; Institute of Chemistry and Biochemistry, Free University of Berlin, Germany
| | - Joschka Willemsen
- Research Group "Dynamics of Early Viral Infection and the Innate Antiviral Response" (division F170), German Cancer Research Center, 69120 Heidelberg, Germany
| | - Sehoon Park
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Ji Woo Park
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA; Biology Department, Boston College, Chestnut Hill, MA, USA
| | - Seong-Wook Oh
- Laboratory of Molecular Genetics, Institute for Frontier Life and Medical Sciences, Kyoto University, Japan
| | - Takashi Fujita
- Laboratory of Molecular Genetics, Institute for Frontier Life and Medical Sciences, Kyoto University, Japan
| | - Fajian Hou
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, China
| | - Marco Binder
- Research Group "Dynamics of Early Viral Infection and the Innate Antiviral Response" (division F170), German Cancer Research Center, 69120 Heidelberg, Germany
| | - Sun Hur
- Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA.
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81
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Crickard JB, Greene EC. Helicase Mechanisms During Homologous Recombination in Saccharomyces cerevisiae. Annu Rev Biophys 2019; 48:255-273. [PMID: 30857400 DOI: 10.1146/annurev-biophys-052118-115418] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helicases are enzymes that move, manage, and manipulate nucleic acids. They can be subdivided into six super families and are required for all aspects of nucleic acid metabolism. In general, all helicases function by converting the chemical energy stored in the bond between the gamma and beta phosphates of adenosine triphosphate into mechanical work, which results in the unidirectional movement of the helicase protein along one strand of a nucleic acid. The results of this translocation activity can range from separation of strands within duplex nucleic acids to the physical remodeling or removal of nucleoprotein complexes. In this review, we focus on describing key helicases from the model organism Saccharomyces cerevisiae that contribute to the regulation of homologous recombination, which is an essential DNA repair pathway for fixing damaged chromosomes.
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Affiliation(s)
- J Brooks Crickard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
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82
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Feng Z, Lemon SM. Innate Immunity to Enteric Hepatitis Viruses. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033464. [PMID: 29686040 DOI: 10.1101/cshperspect.a033464] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although hepatitis A virus (HAV) and hepatitis E virus (HEV) are both positive-strand RNA viruses that replicate in the cytoplasm of hepatocytes, there are important differences in the ways they induce and counteract host innate immune responses. HAV is remarkably stealthy because of its ability to evade and disrupt innate signaling pathways that lead to interferon production. In contrast, HEV does not block interferon production. Instead, it persists in the presence of an interferon response. These differences may provide insight into HEV persistence in immunocompromised patients, an emerging health problem in developed countries.
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Affiliation(s)
- Zongdi Feng
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, Ohio 43205
| | - Stanley M Lemon
- Departments of Medicine and Microbiology & Immunology, Lineberger Comprehensive Cancer Center, The University of North Carolina, Chapel Hill, North Carolina 27599
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83
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The Interaction of Bluetongue Virus VP6 and Genomic RNA Is Essential for Genome Packaging. J Virol 2019; 93:JVI.02023-18. [PMID: 30541863 PMCID: PMC6384066 DOI: 10.1128/jvi.02023-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 12/10/2018] [Indexed: 02/06/2023] Open
Abstract
The genomes of the Reoviridae, including the animal pathogen bluetongue virus (BTV), are multisegmented double-stranded RNA (dsRNA). During replication, single-stranded (ss) positive-sense RNA segments are packaged into the assembling virus capsid, triggering genomic dsRNA synthesis. However, exactly how this packaging event occurs is not clear. A minor capsid protein, VP6, unique for the orbiviruses, has been proposed to be involved in the RNA-packaging process. In this study, we sought to characterize the RNA binding activity of VP6 and its functional relevance. A novel proteomic approach was utilized to map the ssRNA/dsRNA binding sites of a purified recombinant protein and the genomic dsRNA binding sites of the capsid-associated VP6. The data revealed that each VP6 protein has multiple distinct RNA-binding regions and that only one region is shared between recombinant and capsid-associated VP6. A combination of targeted mutagenesis and reverse genetics identified the RNA-binding region that is essential for virus replication. Using an in vitro RNA-binding competition assay, a unique cell-free assembly assay, and an in vivo single-cycle replication assay, it was possible to identify a motif within the shared binding region that binds BTV ssRNA preferentially in a manner consistent with specific RNA recruitment during capsid assembly. These data highlight the critical roles that this unique protein plays in orbivirus genome packaging and replication.IMPORTANCE Genome packaging is a critical stage during virus replication. For viruses with segmented genomes, the genome segments need to be correctly packaged into a newly formed capsid. However, the detailed mechanism of this packaging is unclear. Here we focus on VP6, a minor viral protein of bluetongue virus, which is critical for genome packaging. We used multiple approaches, including a robust RNA-protein fingerprinting assay, to map the ssRNA binding sites of recombinant VP6 and the genomic dsRNA binding sites of capsid-associated VP6. By these means, together with virological and biochemical methods, we identify the viral RNA-packaging motif of a segmented dsRNA virus for the first time.
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84
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Abstract
Detection of double-stranded RNAs (dsRNAs) is a central mechanism of innate immune defense in many organisms. We here discuss several families of dsRNA-binding proteins involved in mammalian antiviral innate immunity. These include RIG-I-like receptors, protein kinase R, oligoadenylate synthases, adenosine deaminases acting on RNA, RNA interference systems, and other proteins containing dsRNA-binding domains and helicase domains. Studies suggest that their functions are highly interdependent and that their interdependence could offer keys to understanding the complex regulatory mechanisms for cellular dsRNA homeostasis and antiviral immunity. This review aims to highlight their interconnectivity, as well as their commonalities and differences in their dsRNA recognition mechanisms.
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Affiliation(s)
- Sun Hur
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA
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85
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Fan X, Jin T. Structures of RIG-I-Like Receptors and Insights into Viral RNA Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1172:157-188. [DOI: 10.1007/978-981-13-9367-9_8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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86
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Jiang QX. Structural Variability in the RLR-MAVS Pathway and Sensitive Detection of Viral RNAs. Med Chem 2019; 15:443-458. [PMID: 30569868 PMCID: PMC6858087 DOI: 10.2174/1573406415666181219101613] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 10/23/2018] [Accepted: 12/12/2018] [Indexed: 12/25/2022]
Abstract
Cells need high-sensitivity detection of non-self molecules in order to fight against pathogens. These cellular sensors are thus of significant importance to medicinal purposes, especially for treating novel emerging pathogens. RIG-I-like receptors (RLRs) are intracellular sensors for viral RNAs (vRNAs). Their active forms activate mitochondrial antiviral signaling protein (MAVS) and trigger downstream immune responses against viral infection. Functional and structural studies of the RLR-MAVS signaling pathway have revealed significant supramolecular variability in the past few years, which revealed different aspects of the functional signaling pathway. Here I will discuss the molecular events of RLR-MAVS pathway from the angle of detecting single copy or a very low copy number of vRNAs in the presence of non-specific competition from cytosolic RNAs, and review key structural variability in the RLR / vRNA complexes, the MAVS helical polymers, and the adapter-mediated interactions between the active RLR / vRNA complex and the inactive MAVS in triggering the initiation of the MAVS filaments. These structural variations may not be exclusive to each other, but instead may reflect the adaptation of the signaling pathways to different conditions or reach different levels of sensitivity in its response to exogenous vRNAs.
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Affiliation(s)
- Qiu-Xing Jiang
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, United States
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87
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Liuyu T, Yu K, Ye L, Zhang Z, Zhang M, Ren Y, Cai Z, Zhu Q, Lin D, Zhong B. Induction of OTUD4 by viral infection promotes antiviral responses through deubiquitinating and stabilizing MAVS. Cell Res 2018; 29:67-79. [PMID: 30410068 DOI: 10.1038/s41422-018-0107-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/25/2018] [Accepted: 10/10/2018] [Indexed: 12/24/2022] Open
Abstract
The activity and stability of the adapter protein MAVS (also known as VISA, Cardif and IPS-1), which critically mediates cellular antiviral responses, are extensively regulated by ubiquitination. However, the process whereby MAVS is deubiquitinated is unclear. Here, we report that the ovarian tumor family deubiquitinase 4 (OTUD4) targets MAVS for deubiquitination. Viral infection leads to the IRF3/7-dependent upregulation of OTUD4 which interacts with MAVS to remove K48-linked polyubiquitin chains, thereby maintaining MAVS stability and promoting innate antiviral signaling. Knockout or knockdown of OTUD4 impairs RNA virus-triggered activation of IRF3 and NF-κB, expression of their downstream target genes, and potentiates VSV replication in vitro and in vivo. Consistently, Cre-ER Otud4fl/fl or Lyz2-Cre Otud4fl/fl mice produce decreased levels of type I interferons and proinflammatory cytokines and exhibit increased sensitivity to VSV infection compared to their control littermates. In addition, reconstitution of MAVS into OTUD4-deficient cells restores virus-induced expression of downstream genes and cellular antiviral responses. Together, our findings uncover an essential role of OTUD4 in virus-triggered signaling and contribute to the understanding of deubiquitination-mediated regulation of innate antiviral responses.
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Affiliation(s)
- Tianzi Liuyu
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Keying Yu
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Liya Ye
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Zhidong Zhang
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Man Zhang
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Yujie Ren
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Zeng Cai
- College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Qiyun Zhu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Dandan Lin
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Bo Zhong
- College of Life Sciences, Wuhan University, Wuhan, 430072, China. .,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China.
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88
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Devarkar SC, Schweibenz B, Wang C, Marcotrigiano J, Patel SS. RIG-I Uses an ATPase-Powered Translocation-Throttling Mechanism for Kinetic Proofreading of RNAs and Oligomerization. Mol Cell 2018; 72:355-368.e4. [PMID: 30270105 PMCID: PMC6434538 DOI: 10.1016/j.molcel.2018.08.021] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/15/2018] [Accepted: 08/14/2018] [Indexed: 12/25/2022]
Abstract
RIG-I has a remarkable ability to specifically select viral 5'ppp dsRNAs for activation from a pool of cytosolic self-RNAs. The ATPase activity of RIG-I plays a role in RNA discrimination and activation, but the underlying mechanism was unclear. Using transient-state kinetics, we elucidated the ATPase-driven "kinetic proofreading" mechanism of RIG-I activation and RNA discrimination, akin to DNA polymerases, ribosomes, and T cell receptors. Even in the autoinhibited state of RIG-I, the C-terminal domain kinetically discriminates against self-RNAs by fast off rates. ATP binding facilitates dsRNA engagement but, interestingly, makes RIG-I promiscuous, explaining the constitutive signaling by Singleton-Merten syndrome-linked mutants that bind ATP without hydrolysis. ATP hydrolysis dissociates self-RNAs faster than 5'ppp dsRNA but, more importantly, drives RIG-I oligomerization through translocation, which we show to be regulated by helicase motif IVa. RIG-I translocates directionally from the dsRNA end into the stem region, and the 5'ppp end "throttles" translocation to provide a mechanism for threading and building a signaling-active oligomeric complex.
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Affiliation(s)
- Swapnil C Devarkar
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, USA
| | - Brandon Schweibenz
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, USA
| | - Chen Wang
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Joseph Marcotrigiano
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA.
| | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, USA.
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89
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Kumar S, Jain S. Immune signalling by supramolecular assemblies. Immunology 2018; 155:435-445. [PMID: 30144032 DOI: 10.1111/imm.12995] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 08/10/2018] [Indexed: 12/19/2022] Open
Abstract
Formation of supramolecular assemblies appears to be a general mechanism in immune signalling pathways. These supramolecular assemblies appear to form through a nucleated polymerization mechanism. This review examines selected immune signalling pathways that involve supramolecular assemblies, describes the concepts of protein polymerization, and discusses how those concepts of protein polymerization implicate new elegant ways for signal amplification, setting threshold and noise reduction in these pathways.
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Affiliation(s)
- Santosh Kumar
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana, India
| | - Shweta Jain
- Department of Neurology and Graduate Programs in Neuroscience and Biomedical Sciences, University of California at San Francisco, San Francisco, CA, USA
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90
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Tan X, Sun L, Chen J, Chen ZJ. Detection of Microbial Infections Through Innate Immune Sensing of Nucleic Acids. Annu Rev Microbiol 2018; 72:447-478. [DOI: 10.1146/annurev-micro-102215-095605] [Citation(s) in RCA: 221] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microbial infections are recognized by the innate immune system through germline-encoded pattern recognition receptors (PRRs). As most microbial pathogens contain DNA and/or RNA during their life cycle, nucleic acid sensing has evolved as an essential strategy for host innate immune defense. Pathogen-derived nucleic acids with distinct features are recognized by specific host PRRs localized in endolysosomes and the cytosol. Activation of these PRRs triggers signaling cascades that culminate in the production of type I interferons and proinflammatory cytokines, leading to induction of an antimicrobial state, activation of adaptive immunity, and eventual clearance of the infection. Here, we review recent progress in innate immune recognition of nucleic acids upon microbial infection, including pathways involving endosomal Toll-like receptors, cytosolic RNA sensors, and cytosolic DNA sensors. We also discuss the mechanisms by which infectious microbes counteract host nucleic acid sensing to evade immune surveillance.
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Affiliation(s)
- Xiaojun Tan
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Lijun Sun
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
| | - Jueqi Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Zhijian J. Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
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91
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Lässig C, Lammens K, Gorenflos López JL, Michalski S, Fettscher O, Hopfner KP. Unified mechanisms for self-RNA recognition by RIG-I Singleton-Merten syndrome variants. eLife 2018; 7:e38958. [PMID: 30047865 PMCID: PMC6086658 DOI: 10.7554/elife.38958] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/24/2018] [Indexed: 12/13/2022] Open
Abstract
The innate immune sensor retinoic acid-inducible gene I (RIG-I) detects cytosolic viral RNA and requires a conformational change caused by both ATP and RNA binding to induce an active signaling state and to trigger an immune response. Previously, we showed that ATP hydrolysis removes RIG-I from lower-affinity self-RNAs (Lässig et al., 2015), revealing how ATP turnover helps RIG-I distinguish viral from self-RNA and explaining why a mutation in a motif that slows down ATP hydrolysis causes the autoimmune disease Singleton-Merten syndrome (SMS). Here we show that a different, mechanistically unexplained SMS variant, C268F, which is localized in the ATP-binding P-loop, can signal independently of ATP but is still dependent on RNA. The structure of RIG-I C268F in complex with double-stranded RNA reveals that C268F helps induce a structural conformation in RIG-I that is similar to that induced by ATP. Our results uncover an unexpected mechanism to explain how a mutation in a P-loop ATPase can induce a gain-of-function ATP state in the absence of ATP.
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Affiliation(s)
- Charlotte Lässig
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Katja Lammens
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Jacob Lucián Gorenflos López
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Sebastian Michalski
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Olga Fettscher
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Karl-Peter Hopfner
- Department of BiochemistryLudwig-Maximilians-Universität MünchenMunichGermany
- Gene Center, Ludwig-Maximilians-Universität MünchenMunichGermany
- Center for Integrated Protein Science MunichMunichGermany
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92
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Tan G, Song H, Xu F, Cheng G. When Hepatitis B Virus Meets Interferons. Front Microbiol 2018; 9:1611. [PMID: 30072974 PMCID: PMC6058040 DOI: 10.3389/fmicb.2018.01611] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/28/2018] [Indexed: 12/12/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection imposes a severe burden on global public health. Currently, there are no curative therapies for millions of chronic HBV-infected patients (Lok et al., 2017). Interferon (IFN; including pegylated IFN) is an approved anti-HBV drug that not only exerts direct antiviral activity, but also augments immunity against HBV infection. Through a systematic review of the literature, here we summarize and present recent progress in research regarding the interactions between IFN and HBV as well as dissect the antiviral mechanisms of IFN. We focus on inhibition of HBV replication by IFN-stimulated genes (ISGs) as well as inhibition of IFN signaling by HBV and viral proteins. Finally, we briefly discuss current IFN-based HBV treatment strategies. This review may help to better understand the mechanisms involved in the therapeutic action of IFN as well as the crosstalk between IFN and HBV, and facilitate the development of both direct-acting and immunology-based new HBV drugs.
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Affiliation(s)
- Guangyun Tan
- Department of Immunology, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
| | - Hongxiao Song
- Department of Immunology, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
| | - Fengchao Xu
- Department of Immunology, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China
| | - Genhong Cheng
- Department of Immunology, Institute of Translational Medicine, The First Hospital of Jilin University, Changchun, China.,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, United States.,Center of System Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Suzhou Institute of Systems Medicine, Suzhou, China
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93
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Single-Molecule FRET Analysis of Replicative Helicases. Methods Mol Biol 2018. [PMID: 29971721 DOI: 10.1007/978-1-4939-8556-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Over the recent years single-molecule fluorescence resonance energy transfer (smFRET) technique has proven to be one of the most powerful tools for revealing mechanistic insights into helicase activities. Here we describe details of single-molecule FRET assays for probing DNA unwinding activities as well as functional dynamics by replicative helicases in real time. The ability of smFRET to measure the behavior of biomolecules at a nanometer scale enabled us to address how the leading and lagging strand synthesis are coordinated during DNA replication, to resolve DNA unwinding steps of Bacteriophage T7 helicase, and to observe heterogeneous unwinding patterns modulated by the DNA binding domain of E1 helicase. These single-molecule FRET assays are generally applicable to other replicative and nonreplicative hexameric helicases.
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94
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Banerjee S, Maurya S, Roy R. Single-molecule fluorescence imaging: Generating insights into molecular interactions in virology. J Biosci 2018; 43:519-540. [PMID: 30002270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Single-molecule fluorescence methods remain a challenging yet information-rich set of techniques that allow one to probe the dynamics, stoichiometry and conformation of biomolecules one molecule at a time. Viruses are small (nanometers) in size, can achieve cellular infections with a small number of virions and their lifecycle is inherently heterogeneous with a large number of structural and functional intermediates. Single-molecule measurements that reveal the complete distribution of properties rather than the average can hence reveal new insights into virus infections and biology that are inaccessible otherwise. This article highlights some of the methods and recent applications of single-molecule fluorescence in the field of virology. Here, we have focused on new findings in virus-cell interaction, virus cell entry and transport, viral membrane fusion, genome release, replication, translation, assembly, genome packaging, egress and interaction with host immune proteins that underline the advantage of single-molecule approach to the question at hand. Finally, we discuss the challenges, outlook and potential areas for improvement and future use of single-molecule fluorescence that could further aid our understanding of viruses.
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Affiliation(s)
- Sunaina Banerjee
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, India
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95
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Single-molecule fluorescence imaging: Generating insights into molecular interactions in virology. J Biosci 2018. [DOI: 10.1007/s12038-018-9769-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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96
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Arenaviral Nucleoproteins Suppress PACT-Induced Augmentation of RIG-I Function To Inhibit Type I Interferon Production. J Virol 2018; 92:JVI.00482-18. [PMID: 29669840 DOI: 10.1128/jvi.00482-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 04/13/2018] [Indexed: 12/28/2022] Open
Abstract
RIG-I is a major cytoplasmic sensor of viral pathogen-associated molecular pattern (PAMP) RNA and induces type I interferon (IFN) production upon viral infection. A double-stranded RNA (dsRNA)-binding protein, PACT, plays an important role in potentiating RIG-I function. We have shown previously that arenaviral nucleoproteins (NPs) suppress type I IFN production via their RNase activity to degrade PAMP RNA. We report here that NPs of arenaviruses block the PACT-induced enhancement of RIG-I function to mediate type I IFN production and that this inhibition is dependent on the RNase function of NPs, which is different from that of a known mechanism of other viral proteins to abolish the interaction between PACT and RIG-I. To understand the biological roles of PACT and RIG-I in authentic arenavirus infection, we analyze growth kinetics of recombinant Pichinde virus (PICV), a prototypical arenavirus, in RIG-I knockout (KO) and PACT KO mouse embryonic fibroblast (MEF) cells. Wild-type (WT) PICV grew at higher titers in both KO MEF lines than in normal MEFs, suggesting the important roles of these cellular proteins in restricting virus replication. PICV carrying the NP RNase catalytically inactive mutation could not grow in normal MEFs but could replicate to some extent in both KO MEF lines. The level of virus growth was inversely correlated with the amount of type I IFNs produced. These results suggest that PACT plays an important role in potentiating RIG-I function to produce type I IFNs in order to restrict arenavirus replication and that viral NP RNase activity is essential for optimal viral replication by suppressing PACT-induced RIG-I activation.IMPORTANCE We report here a new role of the nucleoproteins of arenaviruses that can block type I IFN production via their specific inhibition of the cellular protein sensors of virus infection (RIG-I and PACT). Our results suggest that PACT plays an important role in potentiating RIG-I function to produce type I IFNs in order to restrict arenavirus replication. This new knowledge can be exploited for the development of novel antiviral treatments and/or vaccines against some arenaviruses that can cause severe and lethal hemorrhagic fever diseases in humans.
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97
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Koh HR, Roy R, Sorokina M, Tang GQ, Nandakumar D, Patel SS, Ha T. Correlating Transcription Initiation and Conformational Changes by a Single-Subunit RNA Polymerase with Near Base-Pair Resolution. Mol Cell 2018; 70:695-706.e5. [PMID: 29775583 PMCID: PMC5983381 DOI: 10.1016/j.molcel.2018.04.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/23/2018] [Accepted: 04/19/2018] [Indexed: 11/20/2022]
Abstract
We provide a comprehensive analysis of transcription in real time by T7 RNA Polymerase (RNAP) using single-molecule fluorescence resonance energy transfer by monitoring the entire life history of transcription initiation, including stepwise RNA synthesis with near base-pair resolution, abortive cycling, and transition into elongation. Kinetically branching pathways were observed for abortive initiation with an RNAP either recycling on the same promoter or exchanging with another RNAP from solution. We detected fast and slow populations of RNAP in their transition into elongation, consistent with the efficient and delayed promoter release, respectively, observed in ensemble studies. Real-time monitoring of abortive cycling using three-probe analysis showed that the initiation events are stochastically branched into productive and failed transcription. The abortive products are generated primarily from initiation events that fail to progress to elongation, and a majority of the productive events transit to elongation without making abortive products.
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Affiliation(s)
- Hye Ran Koh
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Chemistry, Chung-Ang University, Seoul 06974, Korea
| | - Rahul Roy
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Maria Sorokina
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Guo-Qing Tang
- Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Divya Nandakumar
- Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Rutgers University, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
| | - Taekjip Ha
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Howard Hughes Medical Institute, Baltimore, MD 21205, USA; Departments of Biophysics and Biophysical Chemistry, Biophysics, and Biomedical Engineering, Johns Hopkins University, MD 21205, USA.
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98
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Encapsidated Host Factors in Alphavirus Particles Influence Midgut Infection of Aedes aegypti. Viruses 2018; 10:v10050263. [PMID: 29772674 PMCID: PMC5977256 DOI: 10.3390/v10050263] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/08/2018] [Accepted: 05/11/2018] [Indexed: 12/25/2022] Open
Abstract
Transmission of mosquito-borne viruses requires the efficient infection of both a permissive vertebrate host and a competent mosquito vector. The infectivity of Sindbis virus (SINV), the type species of the Alphavirus genus, is influenced by both the original and new host cell. We have shown that infection of vertebrate cells by SINV, chikungunya virus (CHIKV), and Ross River virus (RRV) produces two subpopulations of virus particles separable based on density. In contrast, a single population of viral particles is produced by mosquito cells. Previous studies demonstrated that the denser vertebrate-derived particles and the mosquito-derived particles contain components of the small subunit of the host cell ribosome, whereas the less dense vertebrate-derived particles do not. Infection of mice with RRV showed that both particle subpopulations are produced in an infected vertebrate, but in a tissue specific manner with serum containing only the less dense version of the virus particles. Previous infectivity studies using SINV particles have shown that the denser particles (SINVHeavy) and mosquito derived particles SINVC6/36 are significantly more infectious in vertebrate cells than the less dense vertebrate derived particles (SINVLight). The current study shows that SINVLight particles, initiate the infection of the mosquito midgut more efficiently than SINVHeavy particles and that this enhanced infectivity is associated with an exacerbated immune response to SINVLight infection in midgut tissues. The enhanced infection of SINVLight is specific to the midgut as intrathoracically injected virus do not exhibit the same fitness advantage. Together, our data indicate a biologically significant role for the SINVLight subpopulation in the efficient transmission from infected vertebrates to the mosquito vector.
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99
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Loeff L, Brouns SJJ, Joo C. Repetitive DNA Reeling by the Cascade-Cas3 Complex in Nucleotide Unwinding Steps. Mol Cell 2018; 70:385-394.e3. [PMID: 29706536 DOI: 10.1016/j.molcel.2018.03.031] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/23/2018] [Accepted: 03/24/2018] [Indexed: 01/12/2023]
Abstract
CRISPR-Cas provides RNA-guided adaptive immunity against invading genetic elements. Interference in type I systems relies on the RNA-guided Cascade complex for target DNA recognition and the Cas3 helicase/nuclease protein for target degradation. Even though the biochemistry of CRISPR interference has been largely covered, the biophysics of DNA unwinding and coupling of the helicase and nuclease domains of Cas3 remains elusive. Here, we employed single-molecule Förster resonance energy transfer (FRET) to probe the helicase activity with high spatiotemporal resolution. We show that Cas3 remains tightly associated with the target-bound Cascade complex while reeling the DNA using a spring-loaded mechanism. This spring-loaded reeling occurs in distinct bursts of 3 bp, which underlie three successive 1-nt unwinding events. Reeling is highly repetitive, allowing Cas3 to repeatedly present its inefficient nuclease domain with single-strand DNA (ssDNA) substrate. Our study reveals that the discontinuous helicase properties of Cas3 and its tight interaction with Cascade ensure controlled degradation of target DNA only.
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Affiliation(s)
- Luuk Loeff
- Kavli Institute of Nanoscience and Department of Bionanoscience, Delft University of Technology, Delft 2629HZ, the Netherlands
| | - Stan J J Brouns
- Kavli Institute of Nanoscience and Department of Bionanoscience, Delft University of Technology, Delft 2629HZ, the Netherlands; Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen 6708WE, the Netherlands.
| | - Chirlmin Joo
- Kavli Institute of Nanoscience and Department of Bionanoscience, Delft University of Technology, Delft 2629HZ, the Netherlands.
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100
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Jiang M, Zhang S, Yang Z, Lin H, Zhu J, Liu L, Wang W, Liu S, Liu W, Ma Y, Zhang L, Cao X. Self-Recognition of an Inducible Host lncRNA by RIG-I Feedback Restricts Innate Immune Response. Cell 2018; 173:906-919.e13. [DOI: 10.1016/j.cell.2018.03.064] [Citation(s) in RCA: 220] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 02/17/2018] [Accepted: 03/26/2018] [Indexed: 12/25/2022]
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