1
|
Procházková M, Füzik T, Grybchuk D, Yurchenko V, Plevka P. Virion structure of Leishmania RNA virus 1. Virology 2022; 577:149-154. [PMID: 36371873 DOI: 10.1016/j.virol.2022.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022]
Abstract
The presence of Leishmania RNA virus 1 (LRV1) enables Leishmania protozoan parasites to cause more severe disease than the virus-free strains. The structure of LRV1 virus-like particles has been determined previously, however, the structure of the LRV1 virion has not been characterized. Here we used cryo-electron microscopy and single-particle reconstruction to determine the structures of the LRV1 virion and empty particle isolated from Leishmania guyanensis to resolutions of 4.0 Å and 3.6 Å, respectively. The capsid of LRV1 is built from sixty dimers of capsid proteins organized with icosahedral symmetry. RNA genomes of totiviruses are replicated inside the virions by RNA polymerases expressed as C-terminal extensions of a sub-population of capsid proteins. Most of the virions probably contain one or two copies of the RNA polymerase, however, the location of the polymerase domains in LRV1 capsid could not be identified, indicating that it varies among particles. Importance. Every year over 200 000 people contract leishmaniasis and more than five hundred people die of the disease. The mucocutaneous form of leishmaniasis produces lesions that can destroy the mucous membranes of the nose, mouth, and throat. Leishmania parasites carrying Leishmania RNA virus 1 (LRV1) are predisposed to cause aggravated symptoms in the mucocutaneous form of leishmaniasis. Here, we present the structure of the LRV1 virion determined using cryo-electron microscopy.
Collapse
Affiliation(s)
- Michaela Procházková
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Tibor Füzik
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Danyil Grybchuk
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Chittussiho 10, Ostrava, 710 00, Czech Republic
| | - Pavel Plevka
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic.
| |
Collapse
|
2
|
Kopelyanskiy D, Desponds C, Prevel F, Rossi M, Migliorini R, Snäkä T, Eren RO, Claudinot S, Lye LF, Pasparakis M, Beverley SM, Fasel N. Leishmania guyanensis suppressed inducible nitric oxide synthase provoked by its viral endosymbiont. Front Cell Infect Microbiol 2022; 12:944819. [PMID: 36034693 PMCID: PMC9416488 DOI: 10.3389/fcimb.2022.944819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Inducible nitric oxide synthase (iNOS) is essential to the production of nitric oxide (NO), an efficient effector molecule against intracellular human pathogens such as Leishmania protozoan parasites. Some strains of Leishmania are known to bear a viral endosymbiont termed Leishmania RNA virus 1 (LRV1). Recognition of LRV1 by the innate immune sensor Toll-like receptor-3 (TLR3) leads to conditions worsening the disease severity in mice. This process is governed by type I interferon (type I IFNs) arising downstream of TLR3 stimulation and favoring the formation of secondary metastatic lesions. The formation of these lesions is mediated by the inflammatory cytokine IL-17A and occurs in the absence, or low level of, protective cytokine IFN-γ. Here, we described that the presence of LRV1 led to the initial expression of iNOS and low production of NO that failed to control infection. We subsequently showed that LRV1-triggered type I IFN was essential but insufficient to induce robust iNOS induction, which requires strong activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Leishmania guyanensis carrying LRV1 (LgyLRV1+) parasites mitigated strong iNOS production by limiting NF-kB activation via the induction of tumor necrosis factor-alpha-induced protein 3 (TNFAIP3), also known as A20. Moreover, our data suggested that production of LRV1-induced iNOS could be correlated with parasite dissemination and metastasis via elevated secretion of IL-17A in the draining lymph nodes. Our findings support an additional strategy by which LRV1-bearing Leishmania guyanensis evaded killing by nitric oxide and suggest that low levels of LRV1-induced NO might contribute to parasite metastasis.
Collapse
Affiliation(s)
| | - Chantal Desponds
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Florence Prevel
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Matteo Rossi
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Romain Migliorini
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Tiia Snäkä
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Remzi Onur Eren
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | | | - Lon-Fye Lye
- Department of Molecular Microbiology, School of Medicine, Washington University, St. Louis, MO, United States
| | - Manolis Pasparakis
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Stephen M. Beverley
- Department of Molecular Microbiology, School of Medicine, Washington University, St. Louis, MO, United States
| | - Nicolas Fasel
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| |
Collapse
|
3
|
Marucci G, Zullino I, Bertuccini L, Camerini S, Cecchetti S, Pietrantoni A, Casella M, Vatta P, Greenwood AD, Fiorillo A, Lalle M. Re-Discovery of Giardiavirus: Genomic and Functional Analysis of Viruses from Giardia duodenalis Isolates. Biomedicines 2021; 9:654. [PMID: 34201207 PMCID: PMC8230311 DOI: 10.3390/biomedicines9060654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/29/2022] Open
Abstract
Giardiasis, caused by the protozoan parasite Giardia duodenalis, is an intestinal diarrheal disease affecting almost one billion people worldwide. A small endosymbiotic dsRNA viruses, G. lamblia virus (GLV), genus Giardiavirus, family Totiviridae, might inhabit human and animal isolates of G. duodenalis. Three GLV genomes have been sequenced so far, and only one was intensively studied; moreover, a positive correlation between GLV and parasite virulence is yet to be proved. To understand the biological significance of GLV infection in Giardia, the characterization of several GLV strains from naturally infected G. duodenalis isolates is necessary. Here we report high-throughput sequencing of four GLVs strains, from Giardia isolates of human and animal origin. We also report on a new, unclassified viral sequence (designed GdRV-2), unrelated to Giardiavirus, encoding and expressing for a single large protein with an RdRp domain homologous to Totiviridae and Botybirnaviridae. The result of our sequencing and proteomic analyses challenge the current knowledge on GLV and strongly suggest that viral capsid protein translation unusually starts with a proline and that translation of the RNA-dependent RNA polymerase (RdRp) occurs via a +1/-2 ribosomal frameshift mechanism. Nucleotide polymorphism, confirmed by mass-spectrometry analysis, was also observed among and between GLV strains. Phylogenetic analysis indicated the occurrence of at least two GLV subtypes which display different phenotypes and transmissibility in experimental infections of a GLV naïve Giardia isolate.
Collapse
Affiliation(s)
- Gianluca Marucci
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
| | - Ilaria Zullino
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
| | - Lucia Bertuccini
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Serena Camerini
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Serena Cecchetti
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Agostina Pietrantoni
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Marialuisa Casella
- Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (L.B.); (S.C.); (S.C.); (A.P.); (M.C.)
| | - Paolo Vatta
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
| | - Alex D. Greenwood
- Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany;
- Department of Veterinary Medicine, Freie Universität Berlin, 14195 Berlin, Germany
| | - Annarita Fiorillo
- Department of Biochemical Science “A. Rossi-Fanelli”, Sapienza University, 00185 Rome, Italy;
| | - Marco Lalle
- Unit of Foodborne and Neglected Parasitic Disease, Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy; (G.M.); (I.Z.); (P.V.)
| |
Collapse
|
4
|
Abstract
Twelve million people worldwide suffer from leishmaniasis, resulting in more than 30 thousand deaths annually. The disease has several variants that differ in their symptoms. Leishmania parasites cause a variety of symptoms, including mucocutaneous leishmaniasis, which results in the destruction of the mucous membranes of the nose, mouth, and throat. The species of Leishmania carrying Leishmania RNA virus 1 (LRV1), from the family Totiviridae, are more likely to cause severe disease and are less sensitive to treatment than those that do not contain the virus. Although the importance of LRV1 for the severity of leishmaniasis was discovered a long time ago, the structure of the virus remained unknown. Here, we present a cryo-electron microscopy reconstruction of the virus-like particle of LRV1 determined to a resolution of 3.65 Å. The capsid has icosahedral symmetry and is formed by 120 copies of a capsid protein assembled in asymmetric dimers. RNA genomes of viruses from the family Totiviridae are synthetized, but not capped at the 5′ end, by virus RNA polymerases. To protect viral RNAs from degradation, capsid proteins of the L-A totivirus cleave the 5′ caps of host mRNAs, creating decoys to overload the cellular RNA quality control system. Capsid proteins of LRV1 form positively charged clefts, which may be the cleavage sites for the 5′ cap of Leishmania mRNAs. The putative RNA binding site of LRV1 is distinct from that of the related L-A virus. The structure of the LRV1 capsid enables the rational design of compounds targeting the putative decapping site. Such inhibitors may be developed into a treatment for mucocutaneous leishmaniasis caused by LRV1-positive species of Leishmania. IMPORTANCE Twelve million people worldwide suffer from leishmaniasis, resulting in more than 30 thousand deaths annually. The disease has several variants that differ in their symptoms. The mucocutaneous form, which leads to disintegration of the nasal septum, lips, and palate, is caused predominantly by Leishmania parasites carrying Leishmania RNA virus 1 (LRV1). Here, we present the structure of the LRV1 capsid determined using cryo-electron microscopy. Capsid proteins of a related totivirus, L-A virus, protect viral RNAs from degradation by cleaving the 5′ caps of host mRNAs. Capsid proteins of LRV1 may have the same function. We show that the LRV1 capsid contains positively charged clefts that may be sites for the cleavage of mRNAs of Leishmania cells. The structure of the LRV1 capsid enables the rational design of compounds targeting the putative mRNA cleavage site. Such inhibitors may be used as treatments for mucocutaneous leishmaniasis.
Collapse
|
5
|
Penn WD, Harrington HR, Schlebach JP, Mukhopadhyay S. Regulators of Viral Frameshifting: More Than RNA Influences Translation Events. Annu Rev Virol 2020; 7:219-238. [PMID: 32600156 DOI: 10.1146/annurev-virology-012120-101548] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Programmed ribosomal frameshifting (PRF) is a conserved translational recoding mechanism found in all branches of life and viruses. In bacteria, archaea, and eukaryotes PRF is used to downregulate protein production by inducing a premature termination of translation, which triggers messenger RNA (mRNA) decay. In viruses, PRF is used to drive the production of a new protein while downregulating the production of another protein, thus maintaining a stoichiometry optimal for productive infection. Traditionally, PRF motifs have been defined by the characteristics of two cis elements: a slippery heptanucleotide sequence followed by an RNA pseudoknot or stem-loop within the mRNA. Recently, additional cis and new trans elements have been identified that regulate PRF in both host and viral translation. These additional factors suggest PRF is an evolutionarily conserved process whose function and regulation we are just beginning to understand.
Collapse
Affiliation(s)
- Wesley D Penn
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Haley R Harrington
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | | | | |
Collapse
|
6
|
Liu JJ, Xiang Y, Sniezko RA, Schoettle AW, Williams H, Zamany A. Characterization of Cronartium ribicola dsRNAs reveals novel members of the family Totiviridae and viral association with fungal virulence. Virol J 2019; 16:118. [PMID: 31623644 PMCID: PMC6796417 DOI: 10.1186/s12985-019-1226-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/23/2019] [Indexed: 01/13/2023] Open
Abstract
Background Mycoviruses were recently discovered in the white pine blister rust (WPBR) fungus Cronartium ribicola (J.C. Fisch.). Detection and characterization of their double stranded RNA (dsRNA) would facilitate understanding of pathogen virulence and disease pathogenesis in WPBR systems. Methods Full-length cDNAs were cloned from the dsRNAs purified from viral-infected C. ribicola, and their cDNA sequences were determined by DNA sequencing. Evolutionary relationships of the dsRNAs with related mycoviruses were determined by phylogenetic analysis. Dynamic distributions of the viral RNAs within samples of their fungal host C. ribicola were investigated by measurement of viral genome prevalence and viral gene expression. Results In this study we identified and characterized five novel dsRNAs from C. ribicola, designated as Cronartium ribicola totivirus 1–5 (CrTV1 to CrTV5). These dsRNA sequences encode capsid protein and RNA-dependent RNA polymerase with significant homologies to dsRNA viruses of the family Totiviridae. Phylogenetic analysis showed that the CrTVs were grouped into two distinct clades. CrTV2 through CrTV5 clustered within the genus Totivirus. CrTV1 along with a few un-assigned dsRNAs constituted a distinct phyletic clade that is genetically distant from presently known genera in the Totiviridae family, indicating that CrTV1 represents a novel genus in the Totiviridae family. The CrTVs were prevalent in fungal samples obtained from infected western white pine, whitebark pine, and limber pines. Viral RNAs were generally expressed at higher levels during in planta mycelium growth than in aeciospores and urediniospores. CrTV4 was significantly associated with C. ribicola virulent pathotype and specific C. ribicola host tree species, suggesting dsRNAs as potential tools for dissection of pathogenic mechanisms of C. ribicola and diagnosis of C. ribicola pathotypes. Conclusion Phylogenetic and expression analyses of viruses in the WPBR pathogen, C. ribicola, have enchanced our understanding of virus diversity in the family Totiviridae, and provided a potential strategy to utilize pathotype-associated mycoviruses to control fungal forest diseases.
Collapse
Affiliation(s)
- Jun-Jun Liu
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada.
| | - Yu Xiang
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, V0H 1Z0, Canada
| | - Richard A Sniezko
- Dorena Genetic Resource Center, USDA Forest Service, Cottage Grove, Oregon, 97424, USA
| | - Anna W Schoettle
- USDA Forest Service, Rocky Mountain Research Station, 240 West Prospect Road, Fort Collins, CO, 80526, USA
| | - Holly Williams
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada
| | - Arezoo Zamany
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada
| |
Collapse
|
7
|
Robinson JI, Beverley SM. Concentration of 2'C-methyladenosine triphosphate by Leishmania guyanensis enables specific inhibition of Leishmania RNA virus 1 via its RNA polymerase. J Biol Chem 2018; 293:6460-6469. [PMID: 29511088 DOI: 10.1074/jbc.ra117.001515] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 02/05/2018] [Indexed: 01/06/2023] Open
Abstract
Leishmania is a widespread trypanosomatid protozoan parasite causing significant morbidity and mortality in humans. The endobiont dsRNA virus Leishmania RNA virus 1 (LRV1) chronically infects some strains, where it increases parasite numbers and virulence in murine leishmaniasis models, and correlates with increased treatment failure in human disease. Previously, we reported that 2'-C-methyladenosine (2CMA) potently inhibited LRV1 in Leishmania guyanensis (Lgy) and Leishmania braziliensis, leading to viral eradication at concentrations above 10 μm Here we probed the cellular mechanisms of 2CMA inhibition, involving metabolism, accumulation, and inhibition of the viral RNA-dependent RNA polymerase (RDRP). Activation to 2CMA triphosphate (2CMA-TP) was required, as 2CMA showed no inhibition of RDRP activity from virions purified on cesium chloride gradients. In contrast, 2CMA-TP showed IC50 values ranging from 150 to 910 μm, depending on the CsCl density of the virion (empty, ssRNA-, and dsRNA-containing). Lgy parasites incubated in vitro with 10 μm 2CMA accumulated 2CMA-TP to 410 μm, greater than the most sensitive RDRP IC50 measured. Quantitative modeling showed good agreement between the degree of LRV1 RDRP inhibition and LRV1 levels. These results establish that 2CMA activity is due to its conversion to 2CMA-TP, which accumulates to levels that inhibit RDRP and cause LRV1 loss. This attests to the impact of the Leishmania purine uptake and metabolism pathways, which allow even a weak RDRP inhibitor to effectively eradicate LRV1 at micromolar concentrations. Future RDRP inhibitors with increased potency may have potential therapeutic applications for ameliorating the increased Leishmania pathogenicity conferred by LRV1.
Collapse
Affiliation(s)
- John I Robinson
- From the Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Stephen M Beverley
- From the Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| |
Collapse
|
8
|
Atkins JF, Loughran G, Bhatt PR, Firth AE, Baranov PV. Ribosomal frameshifting and transcriptional slippage: From genetic steganography and cryptography to adventitious use. Nucleic Acids Res 2016; 44:7007-78. [PMID: 27436286 PMCID: PMC5009743 DOI: 10.1093/nar/gkw530] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/26/2016] [Indexed: 12/15/2022] Open
Abstract
Genetic decoding is not ‘frozen’ as was earlier thought, but dynamic. One facet of this is frameshifting that often results in synthesis of a C-terminal region encoded by a new frame. Ribosomal frameshifting is utilized for the synthesis of additional products, for regulatory purposes and for translational ‘correction’ of problem or ‘savior’ indels. Utilization for synthesis of additional products occurs prominently in the decoding of mobile chromosomal element and viral genomes. One class of regulatory frameshifting of stable chromosomal genes governs cellular polyamine levels from yeasts to humans. In many cases of productively utilized frameshifting, the proportion of ribosomes that frameshift at a shift-prone site is enhanced by specific nascent peptide or mRNA context features. Such mRNA signals, which can be 5′ or 3′ of the shift site or both, can act by pairing with ribosomal RNA or as stem loops or pseudoknots even with one component being 4 kb 3′ from the shift site. Transcriptional realignment at slippage-prone sequences also generates productively utilized products encoded trans-frame with respect to the genomic sequence. This too can be enhanced by nucleic acid structure. Together with dynamic codon redefinition, frameshifting is one of the forms of recoding that enriches gene expression.
Collapse
Affiliation(s)
- John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland School of Microbiology, University College Cork, Cork, Ireland Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Pramod R Bhatt
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| |
Collapse
|
9
|
Abstract
Viral protein synthesis is completely dependent upon the translational machinery of the host cell. However, many RNA virus transcripts have marked structural differences from cellular mRNAs that preclude canonical translation initiation, such as the absence of a 5′ cap structure or the presence of highly structured 5′UTRs containing replication and/or packaging signals. Furthermore, whilst the great majority of cellular mRNAs are apparently monocistronic, RNA viruses must often express multiple proteins from their mRNAs. In addition, RNA viruses have very compact genomes and are under intense selective pressure to optimize usage of the available sequence space. Together, these features have driven the evolution of a plethora of non-canonical translational mechanisms in RNA viruses that help them to meet these challenges. Here, we review the mechanisms utilized by RNA viruses of eukaryotes, focusing on internal ribosome entry, leaky scanning, non-AUG initiation, ribosome shunting, reinitiation, ribosomal frameshifting and stop-codon readthrough. The review will highlight recently discovered examples of unusual translational strategies, besides revisiting some classical cases.
Collapse
Affiliation(s)
- Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Ian Brierley
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| |
Collapse
|
10
|
Poulos BT, Tang KFJ, Pantoja CR, Bonami JR, Lightner DV. Purification and characterization of infectious myonecrosis virus of penaeid shrimp. J Gen Virol 2006; 87:987-996. [PMID: 16528049 DOI: 10.1099/vir.0.81127-0] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The causative agent of myonecrosis affecting cultured Penaeus vannamei in Brazil was demonstrated to be a virus after purification of the agent from infected shrimp tissues. Purified viral particles were injected into specific pathogen-free P. vannamei, resulting in a disease that displayed the same characteristics as those found in the original shrimp used for purification. The virus was named infectious myonecrosis virus (IMNV). The viral particles were icosahedral in shape and 40 nm in diameter, with a buoyant density of 1.366 g ml(-1) in caesium chloride. The genome consisted of a single, double-stranded (dsRNA) molecule of 7560 bp. Sequencing of the viral genome revealed two non-overlapping open reading frames (ORFs). The 5' ORF (ORF 1, nt 136-4953) encoded a putative RNA-binding protein and a capsid protein. The coding region of the RNA-binding protein was located in the first half of ORF 1 and contained a dsRNA-binding motif in the first 60 aa. The second half of ORF 1 encoded a capsid protein, as determined by amino acid sequencing, with a molecular mass of 106 kDa. The 3' ORF (ORF 2, nt 5241-7451) encoded a putative RNA-dependent RNA polymerase (RdRp) with motifs characteristic of totiviruses. Phylogenetic analysis based on the RdRp clustered IMNV with Giardia lamblia virus, a member of the family Totiviridae. Based on these findings, IMNV may be a unique member of the Totiviridae or may represent a new dsRNA virus family that infects invertebrate hosts.
Collapse
Affiliation(s)
- Bonnie T Poulos
- Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA
| | - Kathy F J Tang
- Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA
| | - Carlos R Pantoja
- Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA
| | - Jean Robert Bonami
- UMR 5098, CNRS/IFREMER/UM2, cc080 Place E. Bataillon, 34095 Montpellier Cedex 5, France
| | - Donald V Lightner
- Aquaculture Pathology Laboratory, Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, USA
| |
Collapse
|