1
|
Liao Y, Wang H, Liao H, Sun Y, Tan L, Song C, Qiu X, Ding C. Classification, replication, and transcription of Nidovirales. Front Microbiol 2024; 14:1291761. [PMID: 38328580 PMCID: PMC10847374 DOI: 10.3389/fmicb.2023.1291761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 11/06/2023] [Indexed: 02/09/2024] Open
Abstract
Nidovirales is one order of RNA virus, with the largest single-stranded positive sense RNA genome enwrapped with membrane envelope. It comprises four families (Arterividae, Mesoniviridae, Roniviridae, and Coronaviridae) and has been circulating in humans and animals for almost one century, posing great threat to livestock and poultry,as well as to public health. Nidovirales shares similar life cycle: attachment to cell surface, entry, primary translation of replicases, viral RNA replication in cytoplasm, translation of viral proteins, virion assembly, budding, and release. The viral RNA synthesis is the critical step during infection, including genomic RNA (gRNA) replication and subgenomic mRNAs (sg mRNAs) transcription. gRNA replication requires the synthesis of a negative sense full-length RNA intermediate, while the sg mRNAs transcription involves the synthesis of a nested set of negative sense subgenomic intermediates by a discontinuous strategy. This RNA synthesis process is mediated by the viral replication/transcription complex (RTC), which consists of several enzymatic replicases derived from the polyprotein 1a and polyprotein 1ab and several cellular proteins. These replicases and host factors represent the optimal potential therapeutic targets. Hereby, we summarize the Nidovirales classification, associated diseases, "replication organelle," replication and transcription mechanisms, as well as related regulatory factors.
Collapse
Affiliation(s)
- Ying Liao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Huan Wang
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Huiyu Liao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yingjie Sun
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Lei Tan
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Cuiping Song
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Xusheng Qiu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Chan Ding
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| |
Collapse
|
2
|
Sha H, Zhang H, Chen Y, Huang L, Zhao M, Wang N. Research Progress on the NSP9 Protein of Porcine Reproductive and Respiratory Syndrome Virus. Front Vet Sci 2022; 9:872205. [PMID: 35898550 PMCID: PMC9309524 DOI: 10.3389/fvets.2022.872205] [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: 02/09/2022] [Accepted: 06/20/2022] [Indexed: 11/24/2022] Open
Abstract
Porcine reproductive and respiratory syndrome (PRRS) is a contagious disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV). PRRS is also called “blue ear disease” because of the characteristic blue ear in infected sows and piglets. Its main clinical features are reproductive disorders of sows, breathing difficulties in piglets, and fattening in pigs, which cause considerable losses to the swine industry. NSP9, a non-structural protein of PRRSV, plays a vital role in PRRSV replication and virulence because of its RNA-dependent RNA polymerase (RdRp) structure. The NSP9 sequence is highly conserved and contains T cell epitopes, which are beneficial for the development of future vaccines. NSP9 acts as the protein interaction hub between virus and host during PRRSV infection, especially in RNA replication and transcription. Herein, we comprehensively review the application of NSP9 in terms of genetic evolution analysis, interaction with host proteins that affect virus replication, interaction with other viral proteins, pathogenicity, regulation of cellular immune response, antiviral drugs, vaccines, and detection methods. This review can therefore provide innovative ideas and strategies for PRRSV prevention and control.
Collapse
Affiliation(s)
- Huiyang Sha
- Department of Veterinary Medicine, School of Life Science and Engineering, Foshan University, Foshan, China
- Veterinary Teaching Hospital, Foshan University, Foshan, China
| | - Hang Zhang
- Department of Veterinary Medicine, School of Life Science and Engineering, Foshan University, Foshan, China
- Veterinary Teaching Hospital, Foshan University, Foshan, China
| | - Yao Chen
- Department of Veterinary Medicine, School of Life Science and Engineering, Foshan University, Foshan, China
- Veterinary Teaching Hospital, Foshan University, Foshan, China
| | - Liangzong Huang
- Department of Veterinary Medicine, School of Life Science and Engineering, Foshan University, Foshan, China
- Veterinary Teaching Hospital, Foshan University, Foshan, China
- *Correspondence: Liangzong Huang
| | - Mengmeng Zhao
- Department of Veterinary Medicine, School of Life Science and Engineering, Foshan University, Foshan, China
- Veterinary Teaching Hospital, Foshan University, Foshan, China
- Mengmeng Zhao
| | - Nina Wang
- Department of Veterinary Medicine, School of Life Science and Engineering, Foshan University, Foshan, China
- Veterinary Teaching Hospital, Foshan University, Foshan, China
- Nina Wang
| |
Collapse
|
3
|
Paraoxonase-1 Facilitates PRRSV Replication by Interacting with Viral Nonstructural Protein-9 and Inhibiting Type I Interferon Pathway. Viruses 2022; 14:v14061203. [PMID: 35746674 PMCID: PMC9230610 DOI: 10.3390/v14061203] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/29/2022] [Accepted: 05/29/2022] [Indexed: 02/04/2023] Open
Abstract
Paraoxonase-1 (PON1), an esterase with specifically paraoxonase activity, has been proven to be involved in inflammation and infection. Porcine reproductive and respiratory syndrome virus (PRRSV) is still a major concern in pigs and causes severe economic losses to the swine industry worldwide. In this study, the role of PON1 was investigated in porcine alveolar macrophages (PAMs) during PRRSV infection. The results showed that PRRSV replication downregulated PON1, and the knockdown of PON1 significantly decreased PRRSV replication. Similarly, PON1 overexpression could enhance PRRSV replication. Interestingly, we observed that PON1 interacted with PRRSV nonstructural protein 9 (Nsp9), the RNA-dependent RNA polymerase, and the knockdown of PON1 lowered the RNA binding ability of Nsp9, suggesting that PON1 can facilitate Nsp9 function in viral replication. In addition, the knockdown of PON1 expression led to the amplification of type I interferon (IFN) genes and vice versa. In summary, our data demonstrate that PON1 facilitates PRRSV replication by interacting with Nsp9 and inhibiting the type I IFN signaling pathway. Hence, PON1 may be an additional component of the anti-PRRSV defenses.
Collapse
|
4
|
Grellet E, L'Hôte I, Goulet A, Imbert I. Replication of the coronavirus genome: A paradox among positive-strand RNA viruses. J Biol Chem 2022; 298:101923. [PMID: 35413290 PMCID: PMC8994683 DOI: 10.1016/j.jbc.2022.101923] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 01/18/2023] Open
Abstract
Coronavirus (CoV) genomes consist of positive-sense single-stranded RNA and are among the largest viral RNAs known to date (∼30 kb). As a result, CoVs deploy sophisticated mechanisms to replicate these extraordinarily large genomes as well as to transcribe subgenomic messenger RNAs. Since 2003, with the emergence of three highly pathogenic CoVs (SARS-CoV, MERS-CoV, and SARS-CoV-2), significant progress has been made in the molecular characterization of the viral proteins and key mechanisms involved in CoV RNA genome replication. For example, to allow for the maintenance and integrity of their large RNA genomes, CoVs have acquired RNA proofreading 3'-5' exoribonuclease activity (in nonstructural protein nsp14). In order to replicate the large genome, the viral-RNA-dependent RNA polymerase (RdRp; in nsp12) is supplemented by a processivity factor (made of the viral complex nsp7/nsp8), making it the fastest known RdRp. Lastly, a viral structural protein, the nucleocapsid (N) protein, which is primarily involved in genome encapsidation, is required for efficient viral replication and transcription. Therefore, CoVs are a paradox among positive-strand RNA viruses in the sense that they use both a processivity factor and have proofreading activity reminiscent of DNA organisms in addition to structural proteins that mediate efficient RNA synthesis, commonly used by negative-strand RNA viruses. In this review, we present a historical perspective of these unsuspected discoveries and detail the current knowledge on the core replicative machinery deployed by CoVs.
Collapse
Affiliation(s)
- Emeline Grellet
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France
| | - India L'Hôte
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France
| | - Adeline Goulet
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France
| | - Isabelle Imbert
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France.
| |
Collapse
|
5
|
Bello-Onaghise G, Wang G, Han X, Nsabimana E, Cui W, Yu F, Zhang Y, Wang L, Li Z, Cai X, Li Y. Antiviral Strategies of Chinese Herbal Medicine Against PRRSV Infection. Front Microbiol 2020; 11:1756. [PMID: 32849384 PMCID: PMC7401453 DOI: 10.3389/fmicb.2020.01756] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 07/06/2020] [Indexed: 01/18/2023] Open
Abstract
Bioactive compounds from Traditional Chinese Medicines (TCMs) are gradually becoming an effective alternative in the control of porcine reproductive and respiratory syndrome virus (PRRSV) because most of the commercially available PRRSV vaccines cannot provide full protection against the genetically diverse strains isolated from farms. Besides, the incomplete attenuation procedure involved in the production of modified live vaccines (MLV) may cause them to revert to the more virulence forms. TCMs have shown some promising potentials in bridging this gap. Several investigations have revealed that herbal extracts from TCMs contain molecules with significant antiviral activities against the various stages of the life cycle of PRRSV, and they do this through different mechanisms. They either block PRRSV attachment and entry into cells or inhibits the replication of viral RNA or viral particles assembly and release or act as immunomodulators and pathogenic pathway inhibitors through cytokines regulations. Here, we summarized the various antiviral strategies employed by some TCMs against the different stages of the life cycle of PRRSV under two major classes, including direct-acting antivirals (DAAs) and indirect-acting antivirals (IAAs). We highlighted their mechanisms of action. In conclusion, we recommended that in making plans for the use of TCMs to control PRRSV, the pathway forward must be built on a real understanding of the mechanisms by which bioactive compounds exert their effects. This will provide a template that will guide the focus of collaborative studies among researchers in the areas of bioinformatics, chemistry, and proteomics. Furthermore, available data and procedures to support the efficacy, safety, and quality control levels of TCMs should be well documented without any breach of data integrity and good manufacturing practices.
Collapse
Affiliation(s)
- God'spower Bello-Onaghise
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Department of Animal Science, Faculty of Agriculture, University of Benin, Benin City, Nigeria
| | - Gang Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiao Han
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Department of Animal and Veterinary Science, Chengdu Agricultural College, Chengdu, China
| | - Eliphaz Nsabimana
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - Wenqiang Cui
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - Fei Yu
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - Yuefeng Zhang
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - Linguang Wang
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - Zhengze Li
- Department of Chinese Medicine, Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Xuehui Cai
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yanhua Li
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| |
Collapse
|
6
|
Mapping the Nonstructural Protein Interaction Network of Porcine Reproductive and Respiratory Syndrome Virus. J Virol 2018; 92:JVI.01112-18. [PMID: 30282705 DOI: 10.1128/jvi.01112-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/25/2018] [Indexed: 12/13/2022] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-stranded RNA virus belonging to the family Arteriviridae Synthesis of the viral RNA is directed by replication/transcription complexes (RTC) that are mainly composed of a network of PRRSV nonstructural proteins (nsps) and likely cellular proteins. Here, we mapped the interaction network among PRRSV nsps by using yeast two-hybrid screening in conjunction with coimmunoprecipitation (co-IP) and cotransfection assays. We identified a total of 24 novel interactions and found that the interactions were centered on open reading frame 1b (ORF1b)-encoded nsps that were mainly connected by the transmembrane proteins nsp2, nsp3, and nsp5. Interestingly, the interactions of the core enzymes nsp9 and nsp10 with transmembrane proteins did not occur in a straightforward manner, as they worked in the co-IP assay but were poorly capable of finding each other within intact mammalian cells. Further proof that they can interact within cells required the engineering of N-terminal truncations of both nsp9 and nsp10. However, despite the poor colocalization relationship in cotransfected cells, both nsp9 and nsp10 came together with membrane proteins (e.g., nsp2) at the viral replication and transcription complexes (RTC) in PRRSV-infected cells. Thus, our results indicate the existence of a complex interaction network among PRRSV nsps and raise the possibility that the recruitment of key replicase proteins to membrane-associated nsps may involve some regulatory mechanisms during infection.IMPORTANCE Synthesis of PRRSV RNAs within host cells depends on the efficient and correct assembly of RTC that takes places on modified intracellular membranes. As an important step toward dissecting this poorly understood event, we investigated the interaction network among PRRSV nsps. Our studies established a comprehensive interaction map for PRRSV nsps and revealed important players within the network. The results also highlight the likely existence of a regulated recruitment of the PRRSV core enzymes nsp9 and nsp10 to viral membrane nsps during PRRSV RTC assembly.
Collapse
|
7
|
Xu L, Zhou L, Sun W, Zhang P, Ge X, Guo X, Han J, Yang H. Nonstructural protein 9 residues 586 and 592 are critical sites in determining the replication efficiency and fatal virulence of the Chinese highly pathogenic porcine reproductive and respiratory syndrome virus. Virology 2018; 517:135-147. [PMID: 29397202 PMCID: PMC7111471 DOI: 10.1016/j.virol.2018.01.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 01/20/2018] [Accepted: 01/24/2018] [Indexed: 01/09/2023]
Abstract
The highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) has caused huge economic losses to the swine industry in China. Understanding the molecular basis in relation to the virulence of HP-PRRSV is essential for effectively controlling clinical infection and disease. In the current study, we constructed and rescued a serial of mutant viruses in nsp9 and nsp10 based on the differential amino acid sites between HP-PRRSV JXwn06 and LP-PRRSV HB-1/3.9. The replication efficiency in pulmonary alveolar macrophages (PAMs) and the pathogenicity of the mutant viruses for piglets were analyzed. Our results showed that the mutation of Thr to Ala in 586 and Ser to Thr in 592 of nsp9 decreased the replication efficiency of HP-PRRSV in PAMs, and could attenuate its virulence for piglets, suggesting that the residues 586 and 592 of nsp9 are critical sites natively in determining the fatal virulence of the Chinese HP-PRRSV for piglets.
Collapse
Affiliation(s)
- Lei Xu
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Lei Zhou
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Weifeng Sun
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Pingping Zhang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Xinna Ge
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Xin Guo
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Jun Han
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China
| | - Hanchun Yang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, People's Republic of China.
| |
Collapse
|
8
|
Rappe JCF, de Wilde A, Di H, Müller C, Stalder H, V'kovski P, Snijder E, Brinton MA, Ziebuhr J, Ruggli N, Thiel V. Antiviral activity of K22 against members of the order Nidovirales. Virus Res 2018; 246:28-34. [PMID: 29337162 PMCID: PMC7114538 DOI: 10.1016/j.virusres.2018.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/10/2018] [Accepted: 01/10/2018] [Indexed: 01/31/2023]
Abstract
Recently, a novel antiviral compound (K22) that inhibits replication of a broad range of animal and human coronaviruses was reported to interfere with viral RNA synthesis by impairing double-membrane vesicle (DMV) formation (Lundin et al., 2014). Here we assessed potential antiviral activities of K22 against a range of viruses representing two (sub)families of the order Nidovirales, the Arteriviridae (porcine reproductive and respiratory syndrome virus [PRRSV], equine arteritis virus [EAV] and simian hemorrhagic fever virus [SHFV]), and the Torovirinae (equine torovirus [EToV] and White Bream virus [WBV]). Possible effects of K22 on nidovirus replication were studied in suitable cell lines. K22 concentrations significantly decreasing infectious titres of the viruses included in this study ranged from 25 to 50 μM. Reduction of double-stranded RNA intermediates of viral replication in nidovirus-infected cells treated with K22 confirmed the anti-viral potential of K22. Collectively, the data show that K22 has antiviral activity against diverse lineages of nidoviruses, suggesting that the inhibitor targets a critical and conserved step during nidovirus replication.
Collapse
Affiliation(s)
- Julie Christiane Françoise Rappe
- Institute for Virology and Immunology IVI, Mittelhäusern and Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland.
| | - Adriaan de Wilde
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Han Di
- Department of Biology, 623 Petit Science Center, Georgia State University, 161 Jesse Hill Jr Drive, Atlanta, GA 30303, United States.
| | - Christin Müller
- Institute of Medical Virology, Justus Liebig University, Giessen, Germany.
| | - Hanspeter Stalder
- Institute for Virology and Immunology IVI, Mittelhäusern and Bern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland.
| | - Philip V'kovski
- Institute for Virology and Immunology IVI, Mittelhäusern and Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland.
| | - Eric Snijder
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Margo A Brinton
- Department of Biology, 623 Petit Science Center, Georgia State University, 161 Jesse Hill Jr Drive, Atlanta, GA 30303, United States.
| | - John Ziebuhr
- Institute of Medical Virology, Justus Liebig University, Giessen, Germany.
| | - Nicolas Ruggli
- Institute for Virology and Immunology IVI, Mittelhäusern and Bern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland.
| | - Volker Thiel
- Institute for Virology and Immunology IVI, Mittelhäusern and Bern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland.
| |
Collapse
|
9
|
Posthuma CC, Te Velthuis AJW, Snijder EJ. Nidovirus RNA polymerases: Complex enzymes handling exceptional RNA genomes. Virus Res 2017; 234:58-73. [PMID: 28174054 PMCID: PMC7114556 DOI: 10.1016/j.virusres.2017.01.023] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/24/2017] [Accepted: 01/26/2017] [Indexed: 12/22/2022]
Abstract
Coronaviruses and arteriviruses are distantly related human and animal pathogens that belong to the order Nidovirales. Nidoviruses are characterized by their polycistronic plus-stranded RNA genome, the production of subgenomic mRNAs and the conservation of a specific array of replicase domains, including key RNA-synthesizing enzymes. Coronaviruses (26-34 kilobases) have the largest known RNA genomes and their replication presumably requires a processive RNA-dependent RNA polymerase (RdRp) and enzymatic functions that suppress the consequences of the typically high error rate of viral RdRps. The arteriviruses have significantly smaller genomes and form an intriguing package with the coronaviruses to analyse viral RdRp evolution and function. The RdRp domain of nidoviruses resides in a cleavage product of the replicase polyprotein named non-structural protein (nsp) 12 in coronaviruses and nsp9 in arteriviruses. In all nidoviruses, the C-terminal RdRp domain is linked to a conserved N-terminal domain, which has been coined NiRAN (nidovirus RdRp-associated nucleotidyl transferase). Although no structural information is available, the functional characterization of the nidovirus RdRp and the larger enzyme complex of which it is part, has progressed significantly over the past decade. In coronaviruses several smaller, non-enzymatic nsps were characterized that direct RdRp function, while a 3'-to-5' exoribonuclease activity in nsp14 was implicated in fidelity. In arteriviruses, the nsp1 subunit was found to maintain the balance between genome replication and subgenomic mRNA production. Understanding RdRp behaviour and interactions during RNA synthesis and subsequent processing will be key to rationalising the evolutionary success of nidoviruses and the development of antiviral strategies.
Collapse
Affiliation(s)
- Clara C Posthuma
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, the Netherlands.
| | - Aartjan J W Te Velthuis
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom; Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Eric J Snijder
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, the Netherlands
| |
Collapse
|