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Kokusho R, Katsuma S. Loss of p24 from the Bombyx mori nucleopolyhedrovirus genome results in the formation of cuboidal occlusion bodies. Virology 2021; 559:173-181. [PMID: 33930820 DOI: 10.1016/j.virol.2021.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/30/2022]
Abstract
Some insect viruses produce the occlusion body (OB), a large crystalline particle comprising a viral protein that occludes virions to protect them from harsh environments. The shapes and sizes of OBs are diverse depending on baculovirus species, but the detailed molecular mechanism determining them has yet to be totally clarified yet. Here we generated Bombyx mori nucleopolyhedrovirus (BmNPV) mutants of the p24 gene that encodes a viral capsid protein and found that p24-mutated BmNPVs produced cuboidal OBs with a slightly larger size than typical truncated octahedral OBs produced by wild-type BmNPVs. Meanwhile, p24 disruption has no significant impact on progeny virus production and viral pathogenicity. In addition, we experimentally demonstrated that a single amino acid substitution found in the P24 protein of the BmNPV Cubic isolate caused cuboidal OB production. These results suggest that p24 has a crucial role in generating the typical shape of OBs.
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Affiliation(s)
- Ryuhei Kokusho
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan; Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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2
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Coulibaly F. Polyhedra, spindles, phage nucleus and pyramids: Structural biology of viral superstructures. Adv Virus Res 2019; 105:275-335. [PMID: 31522707 DOI: 10.1016/bs.aivir.2019.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Viral infection causes comprehensive rearrangements of the cell that reflect as much host defense mechanisms as virus-induced structures assembled to facilitate infection. Regardless of their pro- or antiviral role, large intracellular structures are readily detectable by microscopy and often provide a signature characteristic of a specific viral infection. The structural features and localization of these assemblies have thus been commonly used for the diagnostic and classification of viruses since the early days of virology. More recently, characterization of viral superstructures using molecular and structural approaches have revealed very diverse organizations and roles, ranging from dynamic viral factories behaving like liquid organelles to ultra-stable crystals embedding and protecting virions. This chapter reviews the structures, functions and biotechnological applications of virus-induced superstructures with a focus on assemblies that have a regular organization, for which detailed structural descriptions are available. Examples span viruses infecting all domains of life including the assembly of virions into crystalline arrays in eukaryotic and bacterial viruses, nucleus-like compartments involved in the replication of large bacteriophages, and pyramid-like structures mediating the egress of archaeal viruses. Among these superstructures, high-resolution structures are available for crystalline objects produced by insect viruses: viral polyhedra which function as the infectious form of occluded viruses, and spindles which are potent virulence factors of entomopoxviruses. In turn, some of these highly symmetrical objects have been used to develop and validate advanced structural approaches, pushing the boundary of structural biology.
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Affiliation(s)
- Fasséli Coulibaly
- Infection & Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.
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3
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Harrison RL, Rowley DL, Popham HJR. A Novel Alphabaculovirus from the Soybean Looper, Chrysodeixis includens, that Produces Tetrahedral Occlusion Bodies and Encodes Two Copies of he65. Viruses 2019; 11:E579. [PMID: 31247912 PMCID: PMC6669638 DOI: 10.3390/v11070579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/18/2019] [Accepted: 06/21/2019] [Indexed: 11/29/2022] Open
Abstract
Isolates of the alphabaculovirus species, Chrysodeixis includens nucleopolyhedrovirus, have been identified that produce polyhedral occlusion bodies and infect larvae of the soybean looper, Chrysodeixis includens. In this study, we report the discovery and characterization of a novel C. includens-infecting alphabaculovirus, Chrysodeixis includens nucleopolyhedrovirus #1 (ChinNPV#1), that produces tetrahedral occlusion bodies. In bioassays against C. includens larvae, ChinNPV #1 exhibited a degree of pathogenicity that was similar to that of other ChinNPV isolates, but killed larvae more slowly. The host range of ChinNPV#1 was found to be very narrow, with no indication of infection occurring in larvae of Trichoplusia ni and six other noctuid species. The ChinNPV#1 genome sequence was determined to be 130,540 bp, with 126 open reading frames (ORFs) annotated but containing no homologous repeat (hr) regions. Phylogenetic analysis placed ChinNPV#1 in a clade with other Group II alphabaculoviruses from hosts of lepidopteran subfamily Plusiinae, including Chrysodeixis chalcites nucleopolyhedrovirus and Trichoplusia ni single nucleopolyhedrovirus. A unique feature of the ChinNPV#1 genome was the presence of two full-length copies of the he65 ORF. The results indicate that ChinNPV#1 is related to, but distinct from, other ChinNPV isolates.
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Affiliation(s)
- Robert L Harrison
- Invasive Insect Biocontrol and Behavior Laboratory, Beltsville Agricultural Research Center, USDA Agricultural Research Service, Beltsville, MD 20705, USA.
| | - Daniel L Rowley
- Invasive Insect Biocontrol and Behavior Laboratory, Beltsville Agricultural Research Center, USDA Agricultural Research Service, Beltsville, MD 20705, USA
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4
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Ardisson-Araújo DMP, da Silva AMR, Melo FL, Dos Santos ER, Sosa-Gómez DR, Ribeiro BM. A Novel Betabaculovirus Isolated from the Monocot Pest Mocis latipes (Lepidoptera: Noctuidae) and the Evolution of Multiple-Copy Genes. Viruses 2018; 10:v10030134. [PMID: 29547534 PMCID: PMC5869527 DOI: 10.3390/v10030134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/12/2018] [Accepted: 03/14/2018] [Indexed: 01/29/2023] Open
Abstract
In this report, we described the genome of a novel baculovirus isolated from the monocot insect pest Mocis latipes, the striped grass looper. The genome has 134,272 bp in length with a G + C content of 38.3%. Based on the concatenated sequence of the 38 baculovirus core genes, we found that the virus is a betabaculovirus closely related to the noctuid-infecting betabaculoviruses including Pseudaletia unipuncta granulovirus (PsunGV), Trichoplusia ni granulovirus (TnGV), Helicoverpa armigera granulovirus (HearGV), and Xestia c-nigrum granulovirus (XecnGV). The virus may constitute a new Betabaculovirus species tentatively named Mocis latipes granulovirus (MolaGV). After gene content analysis, five open reading frames (ORFs) were found to be unique to MolaGV and several auxiliary genes were found including iap-3, iap-5, bro-a, bro-b, and three enhancins. The virus genome lacked both chitinase and cathepsin. We then looked at the evolutionary history of the enhancin gene and found that betabaculovirus acquired this gene from an alphabaculovirus followed by several duplication events. Gene duplication also happened to an endonuclease-like gene. Genomic and gene content analyses revealed both a strict collinearity and gene expansion into the genome of the MolaGV-related species. We also characterized the granulin gene using a recombinant Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and found that occlusion bodies were produced into the nucleus of infected cells and presented a polyhedral shape and no occluded virions within. Overall, betabaculovirus genome sequencing is of importance to the field as few genomes are publicly accessible. Mocislatipes is a secondary pest of maize, rice, and wheat crops in Brazil. Certainly, both the discovery and description of novel baculoviruses may lead to development of greener and safer pesticides in order to counteract and effectively control crop damage-causing insect populations
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Affiliation(s)
- Daniel M P Ardisson-Araújo
- Laboratory of Insect Virology, Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria RS 97105-900, Brazil.
| | | | - Fernando L Melo
- Laboratory of Baculovirus, Cell Biology Department, University of Brasilia, Brasília DF 70910-900, Brazil.
| | - Ethiane Rozo Dos Santos
- Laboratory of Insect Virology, Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria RS 97105-900, Brazil.
| | - Daniel R Sosa-Gómez
- Embrapa-Soja, Distrito de Warta P.O. Box 231, Londrina PR 86001-970, Brazil.
| | - Bergmann M Ribeiro
- Laboratory of Baculovirus, Cell Biology Department, University of Brasilia, Brasília DF 70910-900, Brazil.
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5
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Shang H, Garretson TA, Kumar CS, Dieter RF, Cheng XW. Improved pFastBac™ donor plasmid vectors for higher protein production using the Bac-to-Bac® baculovirus expression vector system. J Biotechnol 2017. [DOI: 10.1016/j.jbiotec.2017.06.397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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6
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Occurrence and characterization of a tetrahedral nucleopolyhedrovirus from Spilarctia obliqua (Walker). J Invertebr Pathol 2015; 132:135-141. [DOI: 10.1016/j.jip.2015.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/02/2015] [Accepted: 10/05/2015] [Indexed: 11/24/2022]
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7
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Nakai M, Harrison RL, Uchida H, Ukuda R, Hikihara S, Ishii K, Kunimi Y. Isolation of an Adoxophyes orana granulovirus (AdorGV) occlusion body morphology mutant: biological activity, genome sequence and relationship to other isolates of AdorGV. J Gen Virol 2015; 96:904-914. [DOI: 10.1099/jgv.0.000023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Madoka Nakai
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Robert L. Harrison
- Invasive Insect Biocontrol and Behavior Laboratory, USDA Agricultural Research Service (USDA-ARS), Beltsville Agricultural Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705, USA
| | - Haruaki Uchida
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Rie Ukuda
- Yaeyama Branch Office, Okinawa Prefectural Plant Protection Center, 1178-6, Chisokobaru, Hirae, Ishigaki, Okinawa 907-0003, Japan
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Shohei Hikihara
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Kazuo Ishii
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Yasuhisa Kunimi
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
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8
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Ji X, Sutton G, Evans G, Axford D, Owen R, Stuart DI. How baculovirus polyhedra fit square pegs into round holes to robustly package viruses. EMBO J 2010; 29:505-14. [PMID: 19959989 PMCID: PMC2824454 DOI: 10.1038/emboj.2009.352] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 10/30/2009] [Indexed: 11/08/2022] Open
Abstract
Natural protein crystals (polyhedra) armour certain viruses, allowing them to survive for years under hostile conditions. We have determined the structure of polyhedra of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV), revealing a highly symmetrical covalently cross-braced robust lattice, the subunits of which possess a flexible adaptor enabling this supra-molecular assembly to specifically entrap massive baculoviruses. Inter-subunit chemical switches modulate the controlled release of virus particles in the unusual high pH environment of the target insect's gut. Surprisingly, the polyhedrin subunits are more similar to picornavirus coat proteins than to the polyhedrin of cytoplasmic polyhedrosis virus (CPV). It is, therefore, remarkable that both AcMNPV and CPV polyhedra possess identical crystal lattices and crystal symmetry. This crystalline arrangement must be particularly well suited to the functional requirements of the polyhedra and has been either preserved or re-selected during evolution. The use of flexible adaptors to generate a powerful system for packaging irregular particles is characteristic of the AcMNPV polyhedrin and may provide a vehicle to sequester a wide range of objects such as biological nano-particles.
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Affiliation(s)
- Xiaoyun Ji
- Division of Structural Biology, University of Oxford, Henry Wellcome Building of Genomic Medicine, Roosevelt Drive, Oxford, UK
| | - Geoff Sutton
- Division of Structural Biology, University of Oxford, Henry Wellcome Building of Genomic Medicine, Roosevelt Drive, Oxford, UK
| | - Gwyndaf Evans
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, UK
| | - Danny Axford
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, UK
| | - Robin Owen
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, UK
| | - David I Stuart
- Division of Structural Biology, University of Oxford, Henry Wellcome Building of Genomic Medicine, Roosevelt Drive, Oxford, UK
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, UK
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9
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The atomic structure of baculovirus polyhedra reveals the independent emergence of infectious crystals in DNA and RNA viruses. Proc Natl Acad Sci U S A 2009; 106:22205-10. [PMID: 20007786 DOI: 10.1073/pnas.0910686106] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Baculoviruses are ubiquitous insect viruses well known for their use as bioinsecticides, gene therapy vectors, and protein expression systems. Overexpression of recombinant proteins in insect cell culture utilizes the strong promoter of the polyhedrin gene. In infected larvae, the polyhedrin protein forms robust intracellular crystals called polyhedra, which protect encased virions for prolonged periods in the environment. Polyhedra are produced by two unrelated families of insect viruses, baculoviruses and cypoviruses. The atomic structure of cypovirus polyhedra revealed an intricate packing of trimers, which are interconnected by a projecting N-terminal helical arm of the polyhedrin molecule. Baculovirus and cypovirus polyhedra share nearly identical lattices, and the N-terminal region of the otherwise unrelated baculovirus polyhedrin protein sequence is also predicted to be alpha-helical. These results suggest homology between the proteins and a common structural basis for viral polyhedra. Here, we present the 2.2-A structure of baculovirus polyhedra determined by x-ray crystallography from microcrystals produced in vivo. We show that the underlying molecular organization is, in fact, very different. Although both polyhedra have nearly identical unit cell dimensions and share I23 symmetry, the polyhedrin molecules are structurally unrelated and pack differently in the crystals. In particular, disulfide bonds and domain-swapped N-terminal domains stabilize the building blocks of baculovirus polyhedra and interlocking C-terminal arms join unit cells together. We show that the N-terminal projecting helical arms have different structural roles in baculovirus and cypovirus polyhedra and conclude that there is no structural evidence for a common evolutionary origin for both classes of polyhedra.
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10
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Characterization of a new Autographa californica multiple nucleopolyhedrovirus (AcMNPV) polyhedra mutant. Virus Res 2008; 140:1-7. [PMID: 19038296 DOI: 10.1016/j.virusres.2008.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 10/18/2008] [Accepted: 10/20/2008] [Indexed: 11/24/2022]
Abstract
In the very late phase of baculovirus infection, virions are occluded in a crystalline matrix called polyhedra, which is mainly composed of polyhedrin. This protein is highly conserved among baculoviruses and changes in its amino acid sequence may lead to mutant polyhedra. During the purification of an AcMNPV recombinant virus, a mutant virus was isolated. Structural and ultrastrutural analysis by light and transmission electron microscopy (TEM) of insect cells infected with this mutant virus did not show polyhedra formation and differed from the wild-type infection by the presence of a proteinaceous mass dispersed in the cytoplasm and nucleus of the infected cells, which was confirmed by immunogold labelling to be polyhedrin. The polyhedrin gene was amplified by PCR and sequenced. The only change observed was the substitution of a G to a T at the nucleotide +352, which resulted in a Val to Phe change. A recombinant virus was constructed by transferring the mutant gene into a polyhedrin negative virus. The phenotype of this recombinant virus was the same as the mutant one, confirming that this single mutation alone was responsible for the mutant phenotype.
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11
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Jakubowska A, van Oers MM, Cory JS, Ziemnicka J, Vlak JM. European Leucoma salicis NPV is closely related to North American Orgyia pseudotsugata MNPV. J Invertebr Pathol 2005; 88:100-7. [PMID: 15766926 DOI: 10.1016/j.jip.2004.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Revised: 12/15/2004] [Accepted: 12/24/2004] [Indexed: 11/29/2022]
Abstract
The satin moth Leucoma salicis L. (Lepidoptera, Lymantriidae) is a frequent defoliator of poplar trees (Populus spp.) in Europe and Asia (China, Japan). Around 1920 the insect was introduced into the USA and Canada. In this paper, a multicapsid nucleopolyhedrovirus isolated from L. salicis larvae in Poland (LesaNPV) was characterized and appeared to be a variant of Orgyia pseudotsugata (Op) MNPV. O. pseudotsugata, the Douglas fir tussock moth (Lepidoptera, Lymantriidae), occurs exclusively in North America. Sequences of three conserved baculovirus genes, polyhedrin, lef-8, and pif-2, were amplified in polymerase chain reactions using degenerate primer sets, and revealed a high degree of homology to OpMNPV. Restriction enzyme analysis confirmed the close relationship between LesaNPV and OpMNPV, although a number of restriction fragment length polymorphisms were observed. The lef-7 gene, encoding late expression factor 7, and the ctl-2 gene, encoding a conotoxin-like protein, were chosen as putative molecular determinants of the respective viruses. The ctl-2 region appeared suitable for unequivocal identification of either virus as LesaNPV lacked a dUTPase gene in this region. Our observations may suggest that LesaNPV, along with L. salicis, was introduced into O. pseudotsugata after introduction of the former insect into North America in the 1920s.
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Affiliation(s)
- Agata Jakubowska
- Laboratory of Virology, Wageningen University, Binnenhaven 11, Wageningen 6709 PD, The Netherlands
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12
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Cheng XW, Carner GR, Lange M, Jehle JA, Arif BM. Biological and molecular characterization of a multicapsid nucleopolyhedrovirus from Thysanoplusia orichalcea (L.) (Lepidoptera: Noctuidae). J Invertebr Pathol 2005; 88:126-35. [PMID: 15766929 DOI: 10.1016/j.jip.2004.12.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 12/09/2004] [Accepted: 12/24/2004] [Indexed: 11/19/2022]
Abstract
A multicapsid nucleopolyhedrovirus (ThorMNPV) that was co-isolated with a single nucleocapid ThorSNPV from mixed infected larvae of Thysanoplusia orichalcea L. (Lepidoptea: Noctuidae) is characterized. Scanning electron microscopy of ThorMNPV showed a dodecahedral-shaped occlusion body (OB). The occluded virions contained one to as many as eight nucleocapsids/virion. Virion band profiles in gradient centrifugation were consistent in at least 10 rounds of centrifugation from different virion sample preparations. The ThorMNPV had high virulence to third instar Trichoplusia ni and Pseudoplusia includens with LD50 values of 17 and 242OBs per larva, respectively. However, ThorMNPV did not cause mortality in Spodoptera exigua, Spodoptera frugiperda, Spodoptera eridania, Anticarsia gemmatalis, and Helicoverpa zea. ThorMNPV replicates in cells of various tissues such as the fat body and tracheal epithelium cells. T. ni High 5 cells were permissive to ThorMNPV in terms of infection and viral DNA transfection, but SF-21 was less permissive and the infection process was slower. Production of OBs by ThorMNPV in the nuclei of SF-21 was not well pronounced. The genome size of ThorMNPV was estimated to be 136 kb. The polyhedrin gene open reading frame (ORF) was cloned and completely sequenced. The promoter sequence is identical to that of Autographa californica MNPV. Phylogenetic analyses using partial sequences of the polh, lef-8, and lef-9 revealed that ThorMNPV is a member of the Group I NPVs and is related but distinct from the AcMNPV/Rachiplusia ou NPV/Bombyx mori NPV cluster.
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Affiliation(s)
- Xiao-Wen Cheng
- Department of Microbiology, 32 Pearson Hall, Miami University, Oxford, OH 45056, USA.
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Harrison RL, Bonning BC. Comparative analysis of the genomes of Rachiplusia ou and Autographa californica multiple nucleopolyhedroviruses. J Gen Virol 2003; 84:1827-1842. [PMID: 12810877 DOI: 10.1099/vir.0.19146-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Rachiplusia ou multiple nucleopolyhedrovirus (RoMNPV) is a variant of Autographa californica MNPV (AcMNPV) but is significantly more virulent against several major agricultural pests. The genome sequence of the R1 strain of RoMNPV was determined and compared to that of AcMNPV strain C6. The RoMNPV genome is approximately 131.5 kbp with a G+C content of 39.1 %. The homologous repeat regions (hrs) described for AcMNPV-C6 are present in RoMNPV-R1 but the hrs of RoMNPV have fewer palindromic repeats. The RoMNPV-R1 nucleotide sequence is almost completely collinear with the sequence of AcMNPV-C6 and contains homologues of 150 of the 155 ORFs described for AcMNPV-C6. Deletions, insertions and substitutions have resulted in the loss of homologues for AcMNPV ORFs ac2 (bro), ac3 (ctl), ac97, ac121 and ac140 from the RoMNPV genome. The average amino acid sequence identity between RoMNPV and AcMNPV ORFs is 96.1 % and there are differences in promoter motif composition for 23 of these ORFs. Maximum-likelihood analysis of selection pressures on AcMNPV and RoMNPV ORFs indicate that ORFs ro18/ac20-ac21 (arif-1) and ro135/ac143 (odv-e18) have undergone positive selection.
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Affiliation(s)
- Robert L Harrison
- Department of Entomology and Interdepartmental Program in Genetics, Iowa State University, Ames, Iowa 50011, USA
| | - Bryony C Bonning
- Department of Entomology and Interdepartmental Program in Genetics, Iowa State University, Ames, Iowa 50011, USA
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14
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Lin GY, Zhong J, Wang XZ. Abnormal formation of polyhedra resulting from a single mutation in the polyhedrin gene of Autographa californica multicapsid nucleopolyhedrovirus. J Invertebr Pathol 2000; 76:13-9. [PMID: 10963398 DOI: 10.1006/jipa.2000.4934] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A spontaneous mutant that produces a single abnormally large cubic polyhedron per infected cell was isolated from a polyhedra-positive recombinant Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). Both wild-type and mutant virus produce two forms of virus particles, budded virions and occluded virions. However, occluded virions are not found within the polyhedra of cells infected with mutant virus, as with the wild-type virus. These large cubic polyhedra do not have the typical lattice-like structure normally seen in wild-type polyhedra and are noninfectious. Spodoptera frugiperda 9 (SF9) cells which were infected with this virus had low infectivity to larvae. No significant alterations were found in the viral genome by restriction enzyme analysis, and no mutations were found in the 25K gene. A single point mutation resulting in an amino acid change of Gly25 to Asp was identified in the polyhedrin gene. A transfer vector containing the entire polyhedrin gene including the point mutation was constructed and used to cotransfect Sf9 cells with a polyhedron-negative recombinant virus. Large cubic polyhedra were once again observed, confirming that the Gly25 to Asp mutation is responsible for the formation of abnormal polyhedra.
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Affiliation(s)
- G Y Lin
- Institute of Entomology, Zhongshan University, Guangzhou, People's Republic of China
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15
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Cheng XW, Carner GR. Characterization of a single-nucleocapsid nucleopolyhedrovirus of Thysanoplusia orichalcea L. (Lepidoptera: Noctuidae) from Indonesia. J Invertebr Pathol 2000; 75:279-87. [PMID: 10843835 DOI: 10.1006/jipa.2000.4933] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A single-nucleocapsid nucleopolyhedrovirus (NPV) isolated from Thysanoplusia orichalcea L. (Lepidoptera:Noctuidae) (ThorNPV) in Indonesia has tetrahedral occlusion bodies (OBs) with a width of 1. 22 microm (range = 0.803-1.931 microm). The length of the virion with an envelope averaged 0.29 and 0.23 microm without an envelope. ThorNPV was propagated in Pseudoplusia includens (Walker) and its authenticity was confirmed by sequence analysis of the polyhedrin gene of the ThorNPV produced in T. orichalcea and P. includens. Polyhedrin amino acid sequence analysis revealed that ThorNPV belongs to Group II of baculoviruses and is closely related to Trichoplusia ni single nucleocapsid NPV, sharing 97.6% sequence identity. Infectivity of ThorNPV against third instar P. includens was low, with a LD(50) value of 65,636 OBs/larva. Electron microscopy of infected tissues showed many polyhedra without virions embedded, which might explain the low virulence against P. includens. Differences in virion occlusion rates between individual cells in the same tissue suggested that the inoculum consisted of at least two variants that differed in the gene(s) controlling virion occlusion. In a host range test using the LD(50) value to P. includens against Spodoptera exigua, S. frugiperda, S. eridania, Anticarsia gemmatalis, Helicoverpa zea, Trichoplusia ni, and P. includens, P. includens was the only species infected. The virus infected primarily the fat body, tracheal epithelium, and hypodermis. The genomic size of the ThorNPV is 135 kb.
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Affiliation(s)
- X W Cheng
- Department of Entomology, Clemson University, 113 Long Hall, Clemson, South Carolina, 29634-0365, USA
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