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Ning T, Huang W, Min L, Yang Y, Liu S, Xu J, Zhang N, Xie SA, Zhu S, Wang Y. Pseudotyped Viruses for Orthohantavirus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:229-252. [PMID: 36920700 DOI: 10.1007/978-981-99-0113-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Orthohantaviruses, members of the Orthohantavirus genus of Hantaviridae family of the Bunyavirales order, are enveloped, negative-sense, single-stranded, tripartite RNA viruses. They are emerging zoonotic pathogens carried by small mammals including rodents, moles, shrews, and bats and are the etiologic agents of hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS) among humans. With the characteristics of low biological risk but strong operability, a variety of pseudotyped viruses have been constructed as alternatives to authentic orthohantaviruses to help delineate the roles of host factors in viral entry and other virus-host interactions, to assist in deciphering mechanisms of immune response and correlates of protection, to enhance our understanding of viral antigenic property, to characterize viral entry inhibitors, and to be developed as vaccines. In this chapter, we will discuss the general property of orthohantavirus, construction of pseudotyped orthohantaviruses based on different packaging systems, and their current applications.
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Affiliation(s)
- Tingting Ning
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China
| | - Weijin Huang
- Division of HIV/AIDS and Sexually Transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC), Beijing, China
| | - Li Min
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China
| | - Yi Yang
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China
| | - Si Liu
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China
| | - Junxuan Xu
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China
| | - Nan Zhang
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China
| | - Si-An Xie
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China
| | - Shengtao Zhu
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, Beijing, China.
| | - Youchun Wang
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China. .,Institute of Medical Biology, Chinese Academy of Medicine Sciences & Peking Union Medical College, Kunming, China.
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2
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Urrutia CD, Romay G, Shaw BD, Verchot J. Advancing the Rose Rosette Virus Minireplicon and Encapsidation System by Incorporating GFP, Mutations, and the CMV 2b Silencing Suppressor. Viruses 2022; 14:836. [PMID: 35458566 PMCID: PMC9031449 DOI: 10.3390/v14040836] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/01/2022] [Accepted: 04/13/2022] [Indexed: 11/26/2022] Open
Abstract
Plant infecting emaraviruses have segmented negative strand RNA genomes and little is known about their infection cycles due to the lack of molecular tools for reverse genetic studies. Therefore, we innovated a rose rosette virus (RRV) minireplicon containing the green fluorescent protein (GFP) gene to study the molecular requirements for virus replication and encapsidation. Sequence comparisons among RRV isolates and structural modeling of the RNA dependent RNA polymerase (RdRp) and nucleocapsid (N) revealed three natural mutations of the type species isolate that we reverted to the common species sequences: (a) twenty-one amino acid truncations near the endonuclease domain (named delA), (b) five amino acid substitutions near the putative viral RNA binding loop (subT), and (c) four amino acid substitutions in N (NISE). The delA and subT in the RdRp influenced the levels of GFP, gRNA, and agRNA at 3 but not 5 days post inoculation (dpi), suggesting these sequences are essential for initiating RNA synthesis and replication. The NISE mutation led to sustained GFP, gRNA, and agRNA at 3 and 5 dpi indicating that the N supports continuous replication and GFP expression. Next, we showed that the cucumber mosaic virus (CMV strain FNY) 2b singularly enhanced GFP expression and RRV replication. Including agRNA2 with the RRV replicon produced observable virions. In this study we developed a robust reverse genetic system for investigations into RRV replication and virion assembly that could be a model for other emaravirus species.
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Affiliation(s)
| | | | | | - Jeanmarie Verchot
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77845, USA; (C.D.U.); (G.R.); (B.D.S.)
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3
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Abstract
The function of the mammalian orthoreovirus (reovirus) σNS nonstructural protein is enigmatic. σNS is an RNA-binding protein that forms oligomers and enhances the stability of bound RNAs, but the mechanisms by which it contributes to reovirus replication are unknown. To determine the function of σNS-RNA binding in reovirus replication, we engineered σNS mutants deficient in RNA-binding capacity. We found that alanine substitutions of positively charged residues in a predicted RNA-binding domain decrease RNA-dependent oligomerization. To define steps in reovirus replication facilitated by the RNA-binding property of σNS, we established a complementation system in which wild-type or mutant forms of σNS could be tested for the capacity to overcome inhibition of σNS expression. Mutations in σNS that disrupt RNA binding also diminish viral replication and σNS distribution to viral factories. Moreover, viral mRNAs only incorporate into viral factories or factory-like structures (formed following expression of nonstructural protein μNS) when σNS is present and capable of binding RNA. Collectively, these findings indicate that σNS requires positively charged residues in a putative RNA-binding domain to recruit viral mRNAs to sites of viral replication and establish a function for σNS in reovirus replication.
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D'Souza MH, Patel TR. Biodefense Implications of New-World Hantaviruses. Front Bioeng Biotechnol 2020; 8:925. [PMID: 32850756 PMCID: PMC7426369 DOI: 10.3389/fbioe.2020.00925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/17/2020] [Indexed: 01/20/2023] Open
Abstract
Hantaviruses, part of the Bunyaviridae family, are a genus of negative-sense, single-stranded RNA viruses that cause two major diseases: New-World Hantavirus Cardiopulmonary Syndrome and Old-World Hemorrhagic Fever with Renal Syndrome. Hantaviruses generally are found worldwide with each disease corresponding to their respective hemispheres. New-World Hantaviruses spread by specific rodent-host reservoirs and are categorized as emerging viruses that pose a threat to global health and security due to their high mortality rate and ease of transmission. Incidentally, reports of Hantavirus categorization as a bioweapon are often contradicted as both US National Institute of Allergy and Infectious Diseases and the Centers for Disease Control and Prevention refer to them as Category A and C bioagents respectively, each retaining qualitative levels of importance and severity. Concerns of Hantavirus being engineered into a novel bioagent has been thwarted by Hantaviruses being difficult to culture, isolate, and purify limiting its ability to be weaponized. However, the natural properties of Hantaviruses pose a threat that can be exploited by conventional and unconventional forces. This review seeks to clarify the categorization of Hantaviruses as a bioweapon, whilst defining the practicality of employing New-World Hantaviruses and their effect on armies, infrastructure, and civilian targets.
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Affiliation(s)
- Michael Hilary D'Souza
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, AB, Canada
| | - Trushar R Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, AB, Canada.,Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Li Ka Shing Institute of Virology and Discovery Lab, University of Alberta, Edmonton, AB, Canada
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Mittler E, Dieterle ME, Kleinfelter LM, Slough MM, Chandran K, Jangra RK. Hantavirus entry: Perspectives and recent advances. Adv Virus Res 2019; 104:185-224. [PMID: 31439149 DOI: 10.1016/bs.aivir.2019.07.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hantaviruses are important zoonotic pathogens of public health importance that are found on all continents except Antarctica and are associated with hemorrhagic fever with renal syndrome (HFRS) in the Old World and hantavirus pulmonary syndrome (HPS) in the New World. Despite the significant disease burden they cause, no FDA-approved specific therapeutics or vaccines exist against these lethal viruses. The lack of available interventions is largely due to an incomplete understanding of hantavirus pathogenesis and molecular mechanisms of virus replication, including cellular entry. Hantavirus Gn/Gc glycoproteins are the only viral proteins exposed on the surface of virions and are necessary and sufficient to orchestrate virus attachment and entry. In vitro studies have implicated integrins (β1-3), DAF/CD55, and gC1qR as candidate receptors that mediate viral attachment for both Old World and New World hantaviruses. Recently, protocadherin-1 (PCDH1) was demonstrated as a requirement for cellular attachment and entry of New World hantaviruses in vitro and lethal HPS in vivo, making it the first clade-specific host factor to be identified. Attachment of hantavirus particles to cellular receptors induces their internalization by clathrin-mediated, dynamin-independent, or macropinocytosis-like mechanisms, followed by particle trafficking to an endosomal compartment where the fusion of viral and endosomal membranes can occur. Following membrane fusion, which requires cholesterol and acid pH, viral nucleocapsids escape into the cytoplasm and launch genome replication. In this review, we discuss the current mechanistic understanding of hantavirus entry, highlight gaps in our existing knowledge, and suggest areas for future inquiry.
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Affiliation(s)
- Eva Mittler
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Maria Eugenia Dieterle
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Lara M Kleinfelter
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Megan M Slough
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States.
| | - Rohit K Jangra
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States.
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Mutational analysis of Rift Valley fever phlebovirus nucleocapsid protein indicates novel conserved, functional amino acids. PLoS Negl Trop Dis 2017; 11:e0006155. [PMID: 29267287 PMCID: PMC5764413 DOI: 10.1371/journal.pntd.0006155] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 01/11/2018] [Accepted: 12/07/2017] [Indexed: 11/19/2022] Open
Abstract
Rift Valley fever phlebovirus (RVFV; Phenuiviridae, Phlebovirus) is an important mosquito-borne pathogen of both humans and ruminants. The RVFV genome is composed of tripartite, single stranded, negative or ambisense RNAs. The small (S) segment encodes both the nucleocapsid protein (N) and the non-structural protein (NSs). The N protein is responsible for the formation of the viral ribonucleoprotein (RNP) complexes, which are essential in the virus life cycle and for the transcription and replication of the viral genome. There is currently limited knowledge surrounding the roles of the RVFV nucleocapsid protein in viral infection other than its key functions: N protein multimerisation, encapsidation of the RNA genome and interactions with the RNA-dependent RNA polymerase, L. By bioinformatic comparison of the N sequences of fourteen phleboviruses, mutational analysis, minigenome assays and packaging assays, we have further characterised the RVFV N protein. Amino acids P11 and F149 in RVFV N play an essential role in the function of RNPs and are neither associated with N protein multimerisation nor known nucleocapsid protein functions and may have additional roles in the virus life cycle. Amino acid Y30 exhibited increased minigenome activity despite reduced RNA binding capacity. Additionally, we have determined that the N-terminal arm of N protein is not involved in N-L interactions. Elucidating the fundamental processes that involve the nucleocapsid protein will add to our understanding of this important viral protein and may influence future studies in the development of novel antiviral strategies.
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Reuter M, Krüger DH. The nucleocapsid protein of hantaviruses: much more than a genome-wrapping protein. Virus Genes 2017; 54:5-16. [PMID: 29159494 DOI: 10.1007/s11262-017-1522-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 11/11/2017] [Indexed: 12/11/2022]
Abstract
The nucleocapsid (N) protein of hantaviruses represents an impressive example of a viral multifunctional protein. It encompasses properties as diverse as genome packaging, RNA chaperoning, intracellular protein transport, DNA degradation, intervention in host translation, and restricting host immune responses. These functions all rely on the capability of N to interact with RNA and other viral and cellular proteins. We have compiled data on the N protein of different hantavirus species together with information of the recently published three-dimensional structural data of the protein. The array of diverse functional activities accommodated in the hantaviral N protein goes far beyond to be a static structural protein and makes it an interesting target in the development of antiviral therapeutics.
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Affiliation(s)
- Monika Reuter
- Institute of Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany.
| | - Detlev H Krüger
- Institute of Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany
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8
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Crimean-Congo hemorrhagic fever virus nucleocapsid protein has dual RNA binding modes. PLoS One 2017; 12:e0184935. [PMID: 28922369 PMCID: PMC5602631 DOI: 10.1371/journal.pone.0184935] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 09/01/2017] [Indexed: 12/17/2022] Open
Abstract
Crimean Congo hemorrhagic fever, a zoonotic viral disease, has high mortality rate in humans. There is currently no vaccine for Crimean Congo hemorrhagic fever virus (CCHFV) and chemical interventions are limited. The three negative sense genomic RNA segments of CCHFV are specifically encapsidated by the nucleocapsid protein into three ribonucleocapsids, which serve as templates for the viral RNA dependent RNA polymerase. Here we demonstrate that CCHFV nucleocapsid protein has two distinct binding modes for double and single strand RNA. In the double strand RNA binding mode, the nucleocapsid protein preferentially binds to the vRNA panhandle formed by the base pairing of complementary nucleotides at the 5’ and 3’ termini of viral genome. The CCHFV nucleocapsid protein does not have RNA helix unwinding activity and hence does not melt the duplex vRNA panhandle after binding. In the single strand RNA binding mode, the nucleocapsid protein does not discriminate between viral and non-viral RNA molecules. Binding of both vRNA panhandle and single strand RNA induce a conformational change in the nucleocapsid protein. Nucleocapsid protein remains in a unique conformational state due to simultaneously binding of structurally distinct vRNA panhandle and single strand RNA substrates. Although the role of dual RNA binding modes in the virus replication cycle is unknown, their involvement in the packaging of viral genome and regulation of CCHFV replication in conjunction with RdRp and host derived RNA regulators is highly likely.
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9
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Sankar S, Ramamurthy M, Nandagopal B, Sridharan G. Short peptide epitope design from hantaviruses causing HFRS. Bioinformation 2017; 13:231-236. [PMID: 28943728 PMCID: PMC5602290 DOI: 10.6026/97320630013231] [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: 06/15/2017] [Revised: 07/03/2017] [Accepted: 07/05/2017] [Indexed: 12/15/2022] Open
Abstract
Several genotypes of the hantavirus cause hemorrhagic fever with renal syndrome (HFRS) and is an important public health problem
worldwide. There is now growing interest to develop subunit vaccines especially focused to elicit cytotoxic T lymphocyte responses
which are important against viral infection. We identified candidate T-cell epitopes that bind to Class I HLA supertypes towards
identifying potential subunit vaccine entity. These epitopes are conserved in all 5 hantavirus genotypes of HFRS (Hantaan, Dobrava-
Belgrade, Seoul, Gou virus and Amur). The epitopes identified from S and M segment genomes were analyzed for human proteasome
cleavage, transporter associated antigen processing (TAP) efficiency and antigenicity using bioinformatic approaches. The epitope
MRNTIMASK which had the two characteristics of high proteasomal cleavage score and TAP score, also had high antigenicity score.
Our results indicate that this epitope from the nucleocapsid protein may be considered the most favorable moiety for the development
of subunit peptide vaccine.
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Affiliation(s)
- Sathish Sankar
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Sripuram, Vellore 632 055, Tamil Nadu, India
| | - Mageshbabu Ramamurthy
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Sripuram, Vellore 632 055, Tamil Nadu, India
| | - Balaji Nandagopal
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Sripuram, Vellore 632 055, Tamil Nadu, India
| | - Gopalan Sridharan
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Sripuram, Vellore 632 055, Tamil Nadu, India
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Salim NN, Ganaie SS, Roy A, Jeeva S, Mir MA. Targeting a Novel RNA-Protein Interaction for Therapeutic Intervention of Hantavirus Disease. J Biol Chem 2016; 291:24702-24714. [PMID: 27733686 DOI: 10.1074/jbc.m116.750729] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/11/2016] [Indexed: 12/14/2022] Open
Abstract
An evolutionarily conserved sequence at the 5' terminus of hantaviral genomic RNA plays an important role in viral transcription initiation and packaging of the viral genome into viral nucleocapsids. Interaction of viral nucleocapsid protein (N) with this conserved sequence facilitates mRNA translation by a unique N-mediated translation strategy. Whereas this evolutionarily conserved sequence facilitates virus replication with the assistance of N in eukaryotic hosts having multifaceted antiviral defense, we demonstrate its interaction with N presents a novel target for therapeutic intervention of hantavirus disease. Using a high throughput screening approach, we identified three lead inhibitors that bind and induce structural perturbations in N. The inhibitors interrupt N-RNA interaction and abrogate both viral genomic RNA synthesis and N-mediated translation strategy without affecting the canonical translation machinery of the host cell. The inhibitors are well tolerated by cells and inhibit hantavirus replication with the same potency as ribavarin, a commercially available antiviral. We report the identification of a unique chemical scaffold that disrupts a critical RNA-protein interaction in hantaviruses and holds promise for the development of the first anti-hantaviral therapeutic with broad spectrum antiviral activity.
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Affiliation(s)
- Nilshad N Salim
- From the Kansas University Medical Center, Kansas City, Kansas 66160
| | - Safder S Ganaie
- From the Kansas University Medical Center, Kansas City, Kansas 66160
| | - Anuradha Roy
- the University of Kansas, Lawrence, Kansas 66045, and
| | - Subbiah Jeeva
- the College of Veterinary Medicine, Western University of Health Sciences, Pomona, California 91766
| | - Mohammad A Mir
- the College of Veterinary Medicine, Western University of Health Sciences, Pomona, California 91766.
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Möncke-Buchner E, Szczepek M, Bokelmann M, Heinemann P, Raftery MJ, Krüger DH, Reuter M. Sin Nombre hantavirus nucleocapsid protein exhibits a metal-dependent DNA-specific endonucleolytic activity. Virology 2016; 496:67-76. [PMID: 27261891 DOI: 10.1016/j.virol.2016.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/10/2016] [Accepted: 05/12/2016] [Indexed: 01/09/2023]
Abstract
We demonstrate that the nucleocapsid protein of Sin Nombre hantavirus (SNV-N) has a DNA-specific endonuclease activity. Upon incubation of SNV-N with DNA in the presence of magnesium or manganese, we observed DNA digestion in sequence-unspecific manner. In contrast, RNA was not affected under the same conditions. Moreover, pre-treatment of SNV-N with RNase before DNA cleavage increased the endonucleolytic activity. Structure-based protein fold prediction using known structures from the PDB database revealed that Asp residues in positions 88 and 103 of SNV-N show sequence similarity with the active site of the restriction endonuclease HindIII. Crystal structure of HindIII predicts that residues Asp93 and Asp108 are essential for coordination of the metal ions required for HindIII DNA cleavage. Therefore, we hypothesized that homologous residues in SNV-N, Asp88 and Asp103, may have a similar function. Replacing Asp88 and Asp103 by alanine led to an SNV-N protein almost completely abrogated for endonuclease activity.
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Affiliation(s)
- Elisabeth Möncke-Buchner
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Michal Szczepek
- Institute of Medical Physics and Biophysics, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Marcel Bokelmann
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Patrick Heinemann
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Martin J Raftery
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Detlev H Krüger
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Monika Reuter
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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12
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Tang F, Xia H, Wang P, Yang J, Zhao T, Zhang Q, Hu Y, Zhou X. The identification and characterization of nucleic acid chaperone activity of human enterovirus 71 nonstructural protein 3AB. Virology 2014; 464-465:353-364. [PMID: 25113906 PMCID: PMC7112070 DOI: 10.1016/j.virol.2014.07.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/17/2014] [Accepted: 07/22/2014] [Indexed: 11/17/2022]
Abstract
Human enterovirus 71 (EV71) belongs to the genus Enterovirus in the family Picornaviridae and has been recognized as one of the most important pathogens that cause emerging infectious disease. Despite of the importance of EV71, the nonstructural protein 3AB from this virus is little understood for its function during EV71 replication. Here we expressed EV71 3AB protein as recombinant protein in a eukaryotic expression system and uncovered that this protein possesses a nucleic acid helix-destabilizing and strand annealing acceleration activity in a dose-dependent manner, indicating that EV71 3AB is a nucleic acid chaperone protein. Moreover, we characterized the RNA chaperone activity of EV71 3AB, and revealed that divalent metal ions, such as Mg2+ and Zn2+, were able to inhibit the RNA helix-destabilizing activity of 3AB to different extents. Moreover, we determined that 3B plus the last 7 amino acids at the C-terminal of 3A (termed 3B+7) possess the RNA chaperone activity, and five amino acids, i.e. Lys-80, Phe-82, Phe-85, Tyr-89, and Arg-103, are critical and probably the active sites of 3AB for its RNA chaperone activity. This report reveals that EV71 3AB displays an RNA chaperone activity, adds a new member to the growing list of virus-encoded RNA chaperones, and provides novel knowledge about the virology of EV71.
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Affiliation(s)
- Fenfen Tang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China
| | - Hongjie Xia
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China
| | - Peipei Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China
| | - Jie Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China
| | - Tianyong Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China
| | - Qi Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China
| | - Yuanyang Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China.
| | - Xi Zhou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072 China.
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13
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Nucleic acid chaperone activity associated with the arginine-rich domain of human hepatitis B virus core protein. J Virol 2013; 88:2530-43. [PMID: 24352445 DOI: 10.1128/jvi.03235-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
UNLABELLED Hepatitis B virus (HBV) DNA replication occurs within the HBV icosahedral core particles. HBV core protein (HBc) contains an arginine-rich domain (ARD) at its carboxyl terminus. This ARD domain of HBc 149-183 is known to be important for viral replication but not known to have a structure. Recently, nucleocapsid proteins of several viruses have been shown to contain nucleic acid chaperone activity, which can facilitate structural rearrangement of viral genome. Major features of nucleic acid chaperones include highly basic amino acid residues and flexible protein structure. To test the nucleic acid chaperone hypothesis for HBc ARD, we first used the disassembled full-length HBc from Escherichia coli to analyze the nucleic acid annealing and strand displacement activities. To exclude the potential contamination of chaperones from E. coli, we designed synthetic HBc ARD peptides with different lengths and serine phosphorylations. We demonstrated that HBc ARD peptide can behave like a bona fide nucleic acid chaperone and that the chaperone activity depends on basic residues of the ARD domain. The loss of chaperone activity by arginine-to-alanine substitutions in the ARD can be rescued by restoring basic residues in the ARD. Furthermore, the chaperone activity is subject to regulation by phosphorylation and dephosphorylation at the HBc ARD. Interestingly, the HBc ARD can enhance in vitro cleavage activity of RNA substrate by a hammerhead ribozyme. We discuss here the potential significance of the HBc ARD chaperone activity in the context of viral DNA replication, in particular, at the steps of primer translocations and circularization of linear replicative intermediates. IMPORTANCE Hepatitis B virus is a major human pathogen. At present, no effective treatment can completely eradicate the virus from patients with chronic hepatitis B. We report here a novel chaperone activity associated with the viral core protein. Our discovery could lead to a new drug design for more effective treatment against hepatitis B virus in the future.
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Yang J, Cheng Z, Zhang S, Xiong W, Xia H, Qiu Y, Wang Z, Wu F, Qin CF, Yin L, Hu Y, Zhou X. A cypovirus VP5 displays the RNA chaperone-like activity that destabilizes RNA helices and accelerates strand annealing. Nucleic Acids Res 2013; 42:2538-54. [PMID: 24319147 PMCID: PMC3936753 DOI: 10.1093/nar/gkt1256] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
For double-stranded RNA (dsRNA) viruses in the family Reoviridae, their inner capsids function as the machinery for viral RNA (vRNA) replication. Unlike other multishelled reoviruses, cypovirus has a single-layered capsid, thereby representing a simplified model for studying vRNA replication of reoviruses. VP5 is one of the three major cypovirus capsid proteins and functions as a clamp protein to stabilize cypovirus capsid. Here, we expressed VP5 from type 5 Helicoverpa armigera cypovirus (HaCPV-5) in a eukaryotic system and determined that this VP5 possesses RNA chaperone-like activity, which destabilizes RNA helices and accelerates strand annealing independent of ATP. Our further characterization of VP5 revealed that its helix-destabilizing activity is RNA specific, lacks directionality and could be inhibited by divalent ions, such as Mg(2+), Mn(2+), Ca(2+) or Zn(2+), to varying degrees. Furthermore, we found that HaCPV-5 VP5 facilitates the replication initiation of an alternative polymerase (i.e. reverse transcriptase) through a panhandle-structured RNA template, which mimics the 5'-3' cyclization of cypoviral positive-stranded RNA. Given that the replication of negative-stranded vRNA on the positive-stranded vRNA template necessitates the dissociation of the 5'-3' panhandle, the RNA chaperone activity of VP5 may play a direct role in the initiation of reoviral dsRNA synthesis.
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Affiliation(s)
- Jie Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China and Department of Biochemistry, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
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15
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A creature with a hundred waggly tails: intrinsically disordered proteins in the ribosome. CELLULAR AND MOLECULAR LIFE SCIENCES : CMLS 2013. [PMID: 23942625 DOI: 10.1007/s00018‐013‐1446‐6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Intrinsic disorder (i.e., lack of a unique 3-D structure) is a common phenomenon, and many biologically active proteins are disordered as a whole, or contain long disordered regions. These intrinsically disordered proteins/regions constitute a significant part of all proteomes, and their functional repertoire is complementary to functions of ordered proteins. In fact, intrinsic disorder represents an important driving force for many specific functions. An illustrative example of such disorder-centric functional class is RNA-binding proteins. In this study, we present the results of comprehensive bioinformatics analyses of the abundance and roles of intrinsic disorder in 3,411 ribosomal proteins from 32 species. We show that many ribosomal proteins are intrinsically disordered or hybrid proteins that contain ordered and disordered domains. Predicted globular domains of many ribosomal proteins contain noticeable regions of intrinsic disorder. We also show that disorder in ribosomal proteins has different characteristics compared to other proteins that interact with RNA and DNA including overall abundance, evolutionary conservation, and involvement in protein-protein interactions. Furthermore, intrinsic disorder is not only abundant in the ribosomal proteins, but we demonstrate that it is absolutely necessary for their various functions.
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16
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Peng Z, Oldfield CJ, Xue B, Mizianty MJ, Dunker AK, Kurgan L, Uversky VN. A creature with a hundred waggly tails: intrinsically disordered proteins in the ribosome. Cell Mol Life Sci 2013; 71:1477-504. [PMID: 23942625 PMCID: PMC7079807 DOI: 10.1007/s00018-013-1446-6] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/29/2013] [Accepted: 07/31/2013] [Indexed: 01/01/2023]
Abstract
Intrinsic disorder (i.e., lack of a unique 3-D structure) is a common phenomenon, and many biologically active proteins are disordered as a whole, or contain long disordered regions. These intrinsically disordered proteins/regions constitute a significant part of all proteomes, and their functional repertoire is complementary to functions of ordered proteins. In fact, intrinsic disorder represents an important driving force for many specific functions. An illustrative example of such disorder-centric functional class is RNA-binding proteins. In this study, we present the results of comprehensive bioinformatics analyses of the abundance and roles of intrinsic disorder in 3,411 ribosomal proteins from 32 species. We show that many ribosomal proteins are intrinsically disordered or hybrid proteins that contain ordered and disordered domains. Predicted globular domains of many ribosomal proteins contain noticeable regions of intrinsic disorder. We also show that disorder in ribosomal proteins has different characteristics compared to other proteins that interact with RNA and DNA including overall abundance, evolutionary conservation, and involvement in protein–protein interactions. Furthermore, intrinsic disorder is not only abundant in the ribosomal proteins, but we demonstrate that it is absolutely necessary for their various functions.
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Affiliation(s)
- Zhenling Peng
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, T6G 2V4, Canada
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17
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Abstract
Capsid proteins are obligatory components of infectious virions. Their primary structural function is to protect viral genomes during entry and exit from host cells. Evidence suggests that these proteins can also modulate the activity and specificity of viral replication complexes. More recently, it has become apparent that they play critical roles at the virus–host interface. Here, we discuss how capsid proteins of RNA viruses interact with key host cell proteins and pathways to modulate cell physiology in order to benefit virus replication. Capsid–host cell interactions may also have implications for viral disease. Understanding how capsids regulate virus–host interactions may lead to the development of novel antiviral therapies based on targeting the activities of cellular proteins.
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Affiliation(s)
- Steven Willows
- Department of Cell Biology, University of Alberta, 5–14 Medical Sciences Building, Edmonton, T6G 2H7, Canada
| | - Shangmei Hou
- Department of Cell Biology, University of Alberta, 5–14 Medical Sciences Building, Edmonton, T6G 2H7, Canada
| | - Tom C Hobman
- Department of Li Ka Shing Institute of Virology, University of Alberta, 5–14 Medical Sciences Building, Edmonton, T6G 2H7, Canada
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18
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Abstract
The phosphoprotein (P) is virally encoded by the Rhabdoviridae and Paramyxoviridae in the order Mononegavirales. P is a self-associated oligomer and forms complexes with the large viral polymerase protein (L), the nucleocapsid protein (N), and the assembled nucleocapsid. P from different viruses has shown structural diversities even though their essential functions are the same. We systematically mapped the domains in mumps virus (MuV) P and investigated their interactions with nucleocapsid-like particles (NLPs). Similar to other P proteins, MuV P contains N-terminal, central, and C-terminal domains with flexible linkers between neighboring domains. By pulldown assays, we discovered that in addition to the previously proposed nucleocapsid binding domain (residues 343 to 391), the N-terminal region of MuV P (residues 1 to 194) could also bind NLPs. Further analysis of binding kinetics was conducted using surface plasmon resonance. This is the first observation that both the N- and C-terminal regions of a negative-strand RNA virus P are involved in binding the nucleocapsid. In addition, we defined the oligomerization domain (POD) of MuV P as residues 213 to 277 and determined its crystal structure. The tetrameric MuV POD is formed by one pair of long parallel α-helices with another pair in opposite orientation. Unlike the parallel orientation of each α-helix in the tetramer of Sendai virus POD, this represents a novel orientation of a POD where both the N- and the C-terminal domains are at either end of the tetramer. This is consistent with the observation that both the N- and the C-terminal domains are involved in binding the nucleocapsid.
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19
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Godet J, Boudier C, Humbert N, Ivanyi-Nagy R, Darlix JL, Mély Y. Comparative nucleic acid chaperone properties of the nucleocapsid protein NCp7 and Tat protein of HIV-1. Virus Res 2012; 169:349-60. [PMID: 22743066 PMCID: PMC7114403 DOI: 10.1016/j.virusres.2012.06.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022]
Abstract
RNA chaperones are proteins able to rearrange nucleic acid structures towards their most stable conformations. In retroviruses, the reverse transcription of the viral RNA requires multiple and complex nucleic acid rearrangements that need to be chaperoned. HIV-1 has evolved different viral-encoded proteins with chaperone activity, notably Tat and the well described nucleocapsid protein NCp7. We propose here an overview of the recent reports that examine and compare the nucleic acid chaperone properties of Tat and NCp7 during reverse transcription to illustrate the variety of mechanisms of action of the nucleic acid chaperone proteins.
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Affiliation(s)
- Julien Godet
- Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie, UMR 7213 CNRS, Université de Strasbourg, 67401 Illkirch, France
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20
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Ellenbecker M, Sears L, Li P, Lanchy JM, Lodmell JS. Characterization of RNA aptamers directed against the nucleocapsid protein of Rift Valley fever virus. Antiviral Res 2012; 93:330-9. [PMID: 22252167 DOI: 10.1016/j.antiviral.2012.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 12/21/2011] [Accepted: 01/03/2012] [Indexed: 12/23/2022]
Abstract
Nucleocapsid protein (N) is an essential RNA binding protein in many RNA viruses. During replication, N protein encapsidates viral genomic and antigenomic RNA, but not viral mRNA or other cellular RNAs. To discriminate between different species of RNA in a host cell, it is likely that N interacts with specific sequences and/or secondary structures on its target RNA. In this study, we explore the RNA binding properties of N using both natural and artificially selected RNAs as ligands. We found that N binds to RNAs that resemble the terminal panhandle structures of RVFV genomic and antigenomic RNA. Furthermore, we used SELEX to isolate RNA aptamers that bound N with high affinity and determined that N specifically recognizes and binds to GAUU and pyrimidine/guanine motifs. Interestingly, BLAST analysis revealed the presence of these motifs within the coding region of the viral genome, suggesting that N may interact with non-terminal viral RNA sequences during replication. Finally, the aptamer RNAs were used to construct a sensitive fluorescence based sensor of N binding with potential applications for drug screening and imaging methodologies.
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Affiliation(s)
- Mary Ellenbecker
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA
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21
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Abstract
The Bunyaviridae family is comprised of a large number of negative-sense, single-stranded RNA viruses that infect animals, insects, and plants. The tripartite genome of bunyaviruses, encapsidated in the form of individual ribonucleoprotein complexes, encodes four structural proteins, the glycoproteins Gc and Gn, the nucleoprotein N, and the viral polymerase L. Some bunyaviruses also use an ambi-sense strategy to encode the nonstructural proteins NSs and NSm. While some bunyaviruses have a T = 12 icosahedral symmetry, others only have locally ordered capsids, or capsids with no detectable symmetry. Bunyaviruses enter cells through clathrin-mediated endocytosis or phagocytosis. In endosome, viral glycoproteins facilitate membrane fusion at acidic pH, thus allowing bunyaviruses to uncoat and deliver their genomic RNA into host cytoplasm. Bunyaviruses replicate in cytoplasm where the viral polymerase L catalyzes both transcription and replication of the viral genome. While transcription requires a cap primer for initiation and ends at specific termination signals before the 3' end of the template is reached, replication copies the entire template and does not depend on any primer for initiation. This review will discuss some of the most interesting aspects of bunyavirus replication, including L protein/N protein-mediated cap snatching, prime-and-realign for transcription and replication initiation, translation-coupled transcription, sequence/secondary structure-dependent transcription termination, ribonucleoprotein encapsidation, and N protein-mediated initiation of viral protein translation. Recent developments on the structure and functional characterization of the bunyavirus capsid and the RNA synthesis machineries (including both protein L and N) will also be discussed.
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Macneil A, Nichol ST, Spiropoulou CF. Hantavirus pulmonary syndrome. Virus Res 2011; 162:138-47. [PMID: 21945215 DOI: 10.1016/j.virusres.2011.09.017] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 09/10/2011] [Accepted: 09/10/2011] [Indexed: 12/27/2022]
Abstract
Hantavirus pulmonary syndrome (HPS) is a severe disease characterized by a rapid onset of pulmonary edema followed by respiratory failure and cardiogenic shock. The HPS associated viruses are members of the genus Hantavirus, family Bunyaviridae. Hantaviruses have a worldwide distribution and are broadly split into the New World hantaviruses, which includes those causing HPS, and the Old World hantaviruses [including the prototype Hantaan virus (HTNV)], which are associated with a different disease, hemorrhagic fever with renal syndrome (HFRS). Sin Nombre virus (SNV) and Andes virus (ANDV) are the most common causes of HPS in North and South America, respectively. Case fatality of HPS is approximately 40%. Pathogenic New World hantaviruses infect the lung microvascular endothelium without causing any virus induced cytopathic effect. However, virus infection results in microvascular leakage, which is the hallmark of HPS. This article briefly reviews the knowledge on HPS-associated hantaviruses accumulated since their discovery, less than 20 years ago.
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Affiliation(s)
- Adam Macneil
- Viral Special Pathogens Branch, Division of High-consequence Pathogens and Pathology, Centers for Disease Control and Prevention, 1600 Clifton Road, N.E., Atlanta, GA 30333, USA
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23
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Hantaviruses in the americas and their role as emerging pathogens. Viruses 2010; 2:2559-86. [PMID: 21994631 PMCID: PMC3185593 DOI: 10.3390/v2122559] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 11/15/2010] [Accepted: 11/24/2010] [Indexed: 12/17/2022] Open
Abstract
The continued emergence and re-emergence of pathogens represent an ongoing, sometimes major, threat to populations. Hantaviruses (family Bunyaviridae) and their associated human diseases were considered to be confined to Eurasia, but the occurrence of an outbreak in 1993–94 in the southwestern United States led to a great increase in their study among virologists worldwide. Well over 40 hantaviral genotypes have been described, the large majority since 1993, and nearly half of them pathogenic for humans. Hantaviruses cause persistent infections in their reservoir hosts, and in the Americas, human disease is manifest as a cardiopulmonary compromise, hantavirus cardiopulmonary syndrome (HCPS), with case-fatality ratios, for the most common viral serotypes, between 30% and 40%. Habitat disturbance and larger-scale ecological disturbances, perhaps including climate change, are among the factors that may have increased the human caseload of HCPS between 1993 and the present. We consider here the features that influence the structure of host population dynamics that may lead to viral outbreaks, as well as the macromolecular determinants of hantaviruses that have been regarded as having potential contribution to pathogenicity.
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Li J, Zhang Q, Wang T, Li C, Liang M, Li D. Tracking hantavirus nucleocapsid protein using intracellular antibodies. Virol J 2010; 7:339. [PMID: 21092325 PMCID: PMC3002308 DOI: 10.1186/1743-422x-7-339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 11/24/2010] [Indexed: 11/30/2022] Open
Abstract
Background Hantavirus nucleocapsid (N) protein is a multifunctional viral macromolecule involved in multiple stages of the viral replication cycle. The intracellular trafficking of N protein during virus assembly remains unclear. Methods We used N protein-specific intracellular expressed antibodies to track the localization and distribution of Hantaan virus and Seoul virus N protein. The N protein-specific antibody single-chain variable antibody fragments (scFvs), which bind an N-terminal linear epitope (L13F3) and C-terminal conformational domain (H34), were intracellularly expressed in the endoplasmic reticulum (ER) by fusion of the SEKDEL retention signal peptide at the carboxyl terminus, and in the cytoplasm (Cyto) by deletion of the ER membrane target signal peptide. Stable Vero-E6 cell lines expressing intracellular scFvs were either infected with hantavirus or transfected with an N protein expression plasmid; virus replication and N protein intracellular localization were determined. Result N protein co-localized with scFvs in the ER and cytoplasm with or without viral membrane glycoproteins. Hantavirus replication was inhibited in both the scFvs-ER- and scFvs-Cyto-expressing stable cell lines. Conclusion N protein may be expressed in the ER retention signal peptide of KDEL circulating region (ER/cis-Golgi) without the assistance of G protein, and so expression of N protein in both the cytoplasm and within the ER/cis-Golgi plays an important role in virus replication.
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Affiliation(s)
- Jiandong Li
- State Key Laboratory, Molecular Virology and Genetic Engineering, Institute for Viral Disease Control and Prevention, China CDC, 155 Changbai Road, Changping District, Beijing 102206, PR China
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25
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The arginine clusters of the carboxy-terminal domain of the core protein of hepatitis B virus make pleiotropic contributions to genome replication. J Virol 2010; 85:1298-309. [PMID: 21084467 DOI: 10.1128/jvi.01957-10] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The carboxy-terminal domain (CTD) of the core protein of hepatitis B virus is not necessary for capsid assembly. However, the CTD does contribute to encapsidation of pregenomic RNA (pgRNA). The contribution of the CTD to DNA synthesis is less clear. This is the case because some mutations within the CTD increase the proportion of spliced RNA to pgRNA that are encapsidated and reverse transcribed. The CTD contains four clusters of consecutive arginine residues. The contributions of the individual arginine clusters to genome replication are unknown. We analyzed core protein variants in which the individual arginine clusters were substituted with either alanine or lysine residues. We developed assays to analyze these variants at specific steps throughout genome replication. We used a replication template that was not spliced in order to study the replication of only pgRNA. We found that alanine substitutions caused defects at both early and late steps in genome replication. Lysine substitutions also caused defects, but primarily during later steps. These findings demonstrate that the CTD contributes to DNA synthesis pleiotropically and that preserving the charge within the CTD is not sufficient to preserve function.
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26
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Stork J, Kovalev N, Sasvari Z, Nagy PD. RNA chaperone activity of the tombusviral p33 replication protein facilitates initiation of RNA synthesis by the viral RdRp in vitro. Virology 2010; 409:338-47. [PMID: 21071052 PMCID: PMC7173327 DOI: 10.1016/j.virol.2010.10.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 09/19/2010] [Accepted: 10/12/2010] [Indexed: 12/18/2022]
Abstract
Small plus-stranded RNA viruses do not code for RNA helicases that would facilitate the proper folding of viral RNAs during replication. Instead, these viruses might use RNA chaperones as shown here for the essential p33 replication protein of Tomato bushy stunt virus (TBSV). In vitro experiments demonstrate that the purified recombinant p33 promotes strand separation of a DNA/RNA duplex. In addition, p33 renders dsRNA templates sensitive to single-strand specific S1 nuclease, suggesting that p33 can destabilize highly structured RNAs. We also demonstrate that the RNA chaperone activity of p33 facilitates self-cleavage by a ribozyme in vitro. In addition, purified p33 facilitates in vitro RNA synthesis on double-stranded (ds)RNA templates up to 5-fold by a viral RNA-dependent RNA polymerase. We propose that the RNA chaperone activity of p33 facilitates the initiation of plus-strand synthesis as well as affects RNA recombination. Altogether, the TBSV RNA chaperone might perform similar biological functions to the helicases of other RNA viruses with much larger coding capacity.
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Affiliation(s)
- Jozsef Stork
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA
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27
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Brown BA, Panganiban AT. Identification of a region of hantavirus nucleocapsid protein required for RNA chaperone activity. RNA Biol 2010; 7:830-7. [PMID: 21378500 DOI: 10.4161/rna.7.6.13862] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sin Nombre hantavirus (SNV) is a New World hantavirus and causes hantavirus cardiopulmonary syndrome. The viral nucleocapsid protein (N) is an RNA chaperone and has multiple functions important in virus replication. The three negative sense RNA segments of hantaviruses form panhandle structures through imperfect hydrogen bonding of the 5' and 3' termini, and the chaperone activity of N can mediate correct panhandle formation. N also functions during transcription and translation initiation and the chaperone activity of N is likely to be involved in aspects of these processes. Using a series of mutations in the N gene we identified a region of N required for chaperone activity. The N-terminal 100 amino acids of N contain a domain that is both necessary and sufficient for RNA chaperone activity. We propose that this region of N may reside in one of two potential states. First, the region may be highly disordered and function in N-mediated RNA chaperone activity. Alternatively, in trimeric form, the region likely becomes ordered and serves in high affinity vRNA panhandle recognition.
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Affiliation(s)
- Bradley A Brown
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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28
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Gangaramani DR, Eden EL, Shah M, Destefano JJ. The twenty-nine amino acid C-terminal cytoplasmic domain of poliovirus 3AB is critical for nucleic acid chaperone activity. RNA Biol 2010; 7:820-9. [PMID: 21045553 DOI: 10.4161/rna.7.6.13781] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Poliovirus 3AB protein is the first picornavirus protein demonstrated to have nucleic acid chaperone activity. Further characterization of 3AB demonstrates that the C-terminal 22 amino acids (3B region (also referred to as VPg), amino acid 88-109) of the protein is required for chaperone activity, as mutations in this region abrogate nucleic acid binding and chaperone function. Protein 3B alone has no chaperone activity as determined by established assays that include the ability to stimulate nucleic acid hybridization in a primer-template annealing assay, helix-destabilization in a nucleic acid unwinding assay, or aggregation of nucleic acids. In contrast, the putative 3AB C-terminal cytoplasmic domain (C terminal amino acids 81-109, 3B + the last 7 C-terminal amino acids of 3A, termed 3B+7 in this report) possesses strong activity in these assays, albeit at much higher concentrations than 3AB. The characteristics of several mutations in 3B+7 are described here, as well as a model proposing that 3B+7 is the site of the "intrinsic" chaperone activity of 3AB while the 3A N-terminal region (amino acids 1-58) and/or membrane anchor domain (amino acids 59-80) serve to increase the effective concentration of the 3B+7 region leading to the potent chaperone activity of 3AB.
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Affiliation(s)
- Divya R Gangaramani
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
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29
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Gultyaev AP, Fouchier RAM, Olsthoorn RCL. Influenza virus RNA structure: unique and common features. Int Rev Immunol 2010; 29:533-56. [PMID: 20923332 DOI: 10.3109/08830185.2010.507828] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The influenza A virus genome consists of eight negative-sense RNA segments. Here we review the currently available data on structure-function relationships in influenza virus RNAs. Various ideas and hypotheses about the roles of influenza virus RNA folding in the virus replication are also discussed in relation to other viruses.
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30
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Abstract
Hantaviruses, members of the Bunyaviridae family, are emerging category A pathogens that initiate the translation of their capped mRNAs by a novel mechanism mediated by viral nucleocapsid protein (N). N specifically binds to the mRNA 5' m7G cap and 40S ribosomal subunit, a complex of 18S rRNA and multiple ribosomal proteins. Here, we show that N specifically interacts with the ribosomal protein S19 (RPS19), located at the head region of the 40S subunit. We suggest that this N-RPS19 interaction facilitates ribosome loading on capped mRNAs during N-mediated translation initiation.
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31
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Ma Y, Tong X, Xu X, Li X, Lou Z, Rao Z. Structures of the N- and C-terminal domains of MHV-A59 nucleocapsid protein corroborate a conserved RNA-protein binding mechanism in coronavirus. Protein Cell 2010; 1:688-97. [PMID: 21203940 PMCID: PMC4875274 DOI: 10.1007/s13238-010-0079-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 06/07/2010] [Indexed: 11/24/2022] Open
Abstract
Coronaviruses are the causative agent of respiratory and enteric diseases in animals and humans. One example is SARS, which caused a worldwide health threat in 2003. In coronaviruses, the structural protein N (nucleocapsid protein) associates with the viral RNA to form the filamentous nucleocapsid and plays a crucial role in genome replication and transcription. The structure of Nterminal domain of MHV N protein also implicated its specific affinity with transcriptional regulatory sequence (TRS) RNA. Here we report the crystal structures of the two proteolytically resistant N- (NTD) and C-terminal (CTD) domains of the N protein from murine hepatitis virus (MHV). The structure of NTD in two different crystal forms was solved to 1.5 Å. The higher resolution provides more detailed structural information than previous reports, showing that the NTD structure from MHV shares a similar overall and topology structure with that of SARS-CoV and IBV, but varies in its potential surface, which indicates a possible difference in RNA-binding module. The structure of CTD was solved to 2.0-Å resolution and revealed a tightly intertwined dimer. This is consistent with analytical ultracentrifugation experiments, suggesting a dimeric assembly of the N protein. The similarity between the structures of these two domains from SARS-CoV, IBV and MHV corroborates a conserved mechanism of nucleocapsid formation for coronaviruses.
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Affiliation(s)
- Yanlin Ma
- Life National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
- Graduate University of the Chinese Academy of Sciences, Beijing, 100049 China
| | - Xiaohang Tong
- Life National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
- Graduate University of the Chinese Academy of Sciences, Beijing, 100049 China
| | - Xiaoling Xu
- Laboratory of Structural Biology, Tsinghua University, Beijing, 100084 China
| | - Xuemei Li
- Life National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Zhiyong Lou
- Laboratory of Structural Biology, Tsinghua University, Beijing, 100084 China
| | - Zihe Rao
- Life National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
- Laboratory of Structural Biology, Tsinghua University, Beijing, 100084 China
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32
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The triplet repeats of the Sin Nombre hantavirus 5' untranslated region are sufficient in cis for nucleocapsid-mediated translation initiation. J Virol 2010; 84:8937-44. [PMID: 20573811 DOI: 10.1128/jvi.02720-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hantavirus nucleocapsid protein (N) can replace the cellular cap-binding complex, eukaryotic initiation factor 4F (eIF4F), to mediate translation initiation. Although N can augment translation initiation of nonviral mRNA, initiation of viral mRNA by N is superior. All members of the Bunyaviridae family, including the species of the hantavirus genus, express either three or four primary mRNAs from their tripartite negative-sense genomes. The 5' ends of the mRNAs contain nonviral heterologous oligonucleotides that originate from endonucleolytic cleavage of cellular mRNA during the process of cap snatching. In the hantaviruses these caps terminate with a 3' G residue followed by nucleotides arising from the viral template. Further, the 5' untranslated region (UTR) of viral mRNA uniformly contains, near the 5' end, either two or three copies of the triplet repeat sequence, UAGUAG or UAGUAGUAG. Through analysis of a panel of mutants with mutations in the viral UTR, we found that the sequence GUAGUAG is sufficient for preferential N-mediated translation initiation and for high-affinity binding of N to the UTR. This heptanucleotide sequence is present in viral mRNA containing either two or three copies of the triplet repeat.
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Ilkow CS, Willows SD, Hobman TC. Rubella virus capsid protein: a small protein with big functions. Future Microbiol 2010; 5:571-84. [PMID: 20353299 DOI: 10.2217/fmb.10.27] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Virus replication occurs in the midst of a life or death struggle between the virus and the infected host cell. To limit virus replication, host cells can activate a number of antiviral pathways, the most drastic of which is programmed cell death. Whereas large DNA viruses have the luxury of encoding accessory proteins whose main function is to interfere with host cell defences, the genomes of RNA viruses are not large enough to encode proteins of this type. Recent studies have revealed that proteins encoded by RNA viruses often play multiple roles in the battles between viruses and host cells. In this article, we discuss the many functions of the rubella virus capsid protein. This protein has well-defined roles in virus assembly, but recent research suggests that it also functions to modulate virus replication and block host cell defences.
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Affiliation(s)
- Carolina S Ilkow
- Department of Cell Biology, University of Alberta, Edmonton, AB, T6G 2H7, Canada.
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Tong X, Ma Y, Li X. Expression, crystallization and preliminary crystallographic study of mouse hepatitis virus (MHV) nucleocapsid protein C-terminal domain. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:674-6. [PMID: 20516597 PMCID: PMC2882767 DOI: 10.1107/s1744309110012492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 04/02/2010] [Indexed: 05/29/2023]
Abstract
Mouse hepatitis virus (MHV) belongs to the group II coronaviruses. The virus produces nine genes encoding 11 proteins that could be recognized as structural proteins and nonstructural proteins and are crucial for viral RNA synthesis. The nucleocapsid (N) protein, one of the structural proteins, interacts with the 30.4 kb virus genomic RNA to form the helical nucleocapsid and associates with the membrane glycoprotein via its C-terminus to stabilize virion assembly. Here, the expression and crystallization of the MHV nucleocapsid protein C-terminal domain are reported. The crystals diffracted to 2.20 A resolution and belonged to space group P422, with unit-cell parameters a = 66.6, c = 50.8 A. Assuming the presence of two molecules in the asymmetric unit, the solvent content is 43.0% (V(M) = 2.16 A(3) Da(-1)).
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Affiliation(s)
- Xiaohang Tong
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, People’s Republic of China
| | - Yanlin Ma
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, People’s Republic of China
| | - Xuemei Li
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, People’s Republic of China
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Roberts LO, Jopling CL, Jackson RJ, Willis AE. Viral strategies to subvert the mammalian translation machinery. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 90:313-67. [PMID: 20374746 PMCID: PMC7102724 DOI: 10.1016/s1877-1173(09)90009-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Viruses do not carry their own protein biosynthesis machinery and the translation of viral proteins therefore requires that the virus usurps the machinery of the host cell. To allow optimal translation of viral proteins at the expense of cellular proteins, virus families have evolved a variety of methods to repress the host translation machinery, while allowing effective viral protein synthesis. Many viruses use noncanonical mechanisms that permit translation of their own RNAs under these conditions. Viruses have also developed mechanisms to evade host innate immune responses that would repress translation under conditions of viral infection, in particular PKR activation in response to double-stranded RNA (dsRNA). Importantly, the study of viral translation mechanisms has enormously enhanced our understanding of many aspects of the cellular protein biosynthesis pathway and its components. A number of unusual mechanisms of translation initiation that were first discovered in viruses have since been observed in cellular mRNAs, and it has become apparent that a diverse range of translation mechanisms operates in eukaryotes, allowing subtle regulation of this essential process.
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Affiliation(s)
- Lisa O Roberts
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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Functional replacement of a domain in the rubella virus p150 replicase protein by the virus capsid protein. J Virol 2009; 83:3549-55. [PMID: 19176617 DOI: 10.1128/jvi.02411-08] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rubella virus (RUBV) capsid (C) protein rescues mutants with a lethal deletion between two in-frame NotI sites in the P150 replicase gene, a deletion encompassing nucleotides 1685 to 2192 of the RUBV genome and amino acids (aa) 548 to 717 of P150 (which has a total length of 1,301 aa). The complete domain rescuable by the C protein was mapped to aa 497 to 803 of P150. Introduction of aa 1 to 277 of the C protein (lacking the C-terminal E2 signal sequence) between the NotI sites in the P150 gene in a replicon construct yielded a viable construct that synthesized viral RNA with wild-type kinetics, indicating that C and this region of P150 share a common function. Further genetic analysis revealed that an arginine-rich motif between aa 60 and 68 of the C protein was necessary for the rescue of DeltaNotI deletion mutants and substituted for an arginine-rich motif between aa 731 and 735 of the P150 protein when the C protein was introduced into P150. Possible common functions shared by these arginine-rich motifs include RNA binding and interaction with cell proteins.
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Abstract
Viruses belonging to the family Coronaviridae are unique among RNA viruses because of the unusually large size of their genome, which is of messenger- or positive- or plus-sense. It is ∼30,000 bases or 2–3 times larger than the genomes of most other RNA viruses. Coronaviruses belong to the order Nidovirales, the other three families being the Arteriviridae, Toroviridae and Roniviridae. (For a review of classification and evolutionary relatedness of Nidovirales see Gorbalenya et al. 2006.) This grouping is based on the arrangement and relatedness of open reading frames within their genomes and on the presence in infected cells of multiple subgenomic mRNAs that form a 3'-co-terminal, nested set with the genome. Among the Nidovirales, coronaviruses (and toroviruses) are unique in their possession of a helical nucleocapsid, which is unusual for plus-stranded but not minus-stranded RNA viruses; plus-stranded RNA-containing plant viruses in the Closteroviridae and in the Tobamovirus genus also possess helical capsids. Coronaviruses are very successful and have infected many species of animals, including bats, birds (poultry) and mammals, such as humans and livestock. Coronavirus species are classified into three groups, which were based originally on cross-reacting antibodies and more recently on nucleotide sequence relatedness (Gonzalez et al. 2003). There have been several reviews of coronaviruses published recently and the reader is referred to them for more extensive references (Enjuanes et al. 2006; Masters 2006; Pasternak et al. 2006; Sawicki and Sawicki 2005; Sawicki et al. 2007; Ziebuhr 2005).
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Zúñiga S, Sola I, Cruz JLG, Enjuanes L. Role of RNA chaperones in virus replication. Virus Res 2008; 139:253-66. [PMID: 18675859 PMCID: PMC7114511 DOI: 10.1016/j.virusres.2008.06.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 06/18/2008] [Accepted: 06/23/2008] [Indexed: 01/06/2023]
Abstract
RNA molecules are functionally diverse in part due to their extreme structural flexibility that allows rapid regulation by refolding. RNA folding could be a difficult process as often molecules adopt a spatial conformation that is very stable but not biologically functional, named a kinetic trap. RNA chaperones are non-specific RNA binding proteins that help RNA folding by resolving misfolded structures or preventing their formation. There is a large number of viruses whose genome is RNA that allows some evolutionary advantages, such as rapid genome mutation. On the other hand, regions of the viral RNA genomes can adopt different structural conformations, some of them lacking functional relevance and acting as misfolded intermediates. In fact, for an efficient replication, they often require RNA chaperone activities. There is a growing list of RNA chaperones encoded by viruses involved in different steps of the viral cycle. Also, cellular RNA chaperones have been involved in replication of RNA viruses. This review briefly describes RNA chaperone activities and is focused in the roles that viral or cellular nucleic acid chaperones have in RNA virus replication, particularly in those viruses that require discontinuous RNA synthesis.
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Affiliation(s)
- Sonia Zúñiga
- Centro Nacional de Biotecnología, CSIC, Department of Molecular and Cell Biology, Campus Universitario de Cantoblanco, Darwin 3, 28049 Madrid, Spain
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Spencer KA, Dee M, Britton P, Hiscox JA. Role of phosphorylation clusters in the biology of the coronavirus infectious bronchitis virus nucleocapsid protein. Virology 2007; 370:373-81. [PMID: 17931676 PMCID: PMC7103301 DOI: 10.1016/j.virol.2007.08.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 08/11/2007] [Accepted: 08/16/2007] [Indexed: 01/15/2023]
Abstract
The coronavirus infectious bronchitis virus (IBV) nucleocapsid (N) protein is an RNA binding protein which is phosphorylated at two conserved clusters. Kinetic analysis of RNA binding indicated that the C-terminal phosphorylation cluster was involved in the recognition of viral RNA from non-viral RNA. The IBV N protein has been found to be essential for the successful recovery of IBV using reverse genetics systems. Rescue experiments indicated that phosphorylated N protein recovered infectious IBV more efficiently when compared to modified N proteins either partially or non-phosphorylated. Our data indicate that the phosphorylated form of the IBV N protein plays a role in virus biology.
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Affiliation(s)
- Kelly-Anne Spencer
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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Zúñiga S, Sola I, Moreno JL, Sabella P, Plana-Durán J, Enjuanes L. Coronavirus nucleocapsid protein is an RNA chaperone. Virology 2006; 357:215-27. [PMID: 16979208 PMCID: PMC7111943 DOI: 10.1016/j.virol.2006.07.046] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 07/11/2006] [Accepted: 07/29/2006] [Indexed: 01/19/2023]
Abstract
RNA chaperones are nonspecific nucleic acid binding proteins with long disordered regions that help RNA molecules to adopt its functional conformation. Coronavirus nucleoproteins (N) are nonspecific RNA-binding proteins with long disordered regions. Therefore, we investigated whether transmissible gastroenteritis coronavirus (TGEV) N protein was an RNA chaperone. Purified N protein enhanced hammerhead ribozyme self-cleavage and nucleic acids annealing, which are properties that define RNA chaperones. In contrast, another RNA-binding protein, PTB, did not show these activities. N protein chaperone activity was blocked by specific monoclonal antibodies. Therefore, it was concluded that TGEV N protein is an RNA chaperone. In addition, we have shown that purified severe acute respiratory syndrome (SARS)-CoV N protein also has RNA chaperone activity. In silico predictions of disordered domains showed a similar pattern for all coronavirus N proteins evaluated. Altogether, these data led us to suggest that all coronavirus N proteins might be RNA chaperones.
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Affiliation(s)
- Sonia Zúñiga
- Centro Nacional de Biotecnología, CSIC, Department of Molecular and Cell Biology, Campus Universidad Autónoma, Darwin 3, Cantoblanco, 28049 Madrid, Spain
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Sawicki SG, Sawicki DL, Siddell SG. A contemporary view of coronavirus transcription. J Virol 2006; 81:20-9. [PMID: 16928755 PMCID: PMC1797243 DOI: 10.1128/jvi.01358-06] [Citation(s) in RCA: 405] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Stanley G Sawicki
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine, Toledo, OH 43614, USA
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