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Towards Understanding the Function of Aegerolysins. Toxins (Basel) 2022; 14:toxins14090629. [PMID: 36136567 PMCID: PMC9505663 DOI: 10.3390/toxins14090629] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/04/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022] Open
Abstract
Aegerolysins are remarkable proteins. They are distributed over the tree of life, being relatively widespread in bacteria and fungi, but also present in some insects, plants, protozoa, and viruses. Despite their abundance in cells of certain developmental stages and their presence in secretomes, only a few aegerolysins have been studied in detail. Their function, in particular, is intriguing. Here, we summarize previously published findings on the distribution, molecular interactions, and function of these versatile aegerolysins. They have very diverse protein sequences but a common fold. The machine learning approach of the AlphaFold2 algorithm, which incorporates physical and biological knowledge of protein structures and multisequence alignments, provides us new insights into the aegerolysins and their pore-forming partners, complemented by additional genomic support. We hypothesize that aegerolysins are involved in the mechanisms of competitive exclusion in the niche.
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2
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Zaghloul HAH, Hice R, Arensburger P, Federici BA. Early in vivo transcriptome of Trichoplusia ni ascovirus core genes. J Gen Virol 2022; 103. [PMID: 35441589 DOI: 10.1099/jgv.0.001737] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Ascoviruses are large double-stranded DNA insect viruses that destroy the nucleus and transform each cell into 20 or more viral vesicles for replication. In the present study we used RNA-sequencing to compare the expression of Trichoplusia ni ascovirus 6a1 (TnAV-6a1) core genes during the first week of infection, with emphasis on the first 48 h, comparing transcript levels in major somatic tissues (epidermis, tracheal matrix and fat body), the sites infected initially, with those of the haemolymph, where viral vesicles circulate and most replication occurs. By 48 h post-infection (p.i.), only 26 genes were expressed in somatic tissues at ≥5 log2 reads per kilobase per million, whereas in the haemolymph 48 genes were expressed at a similar level by the same time. Early and high expression of TnAV caspase-2-like gene occurred in all tissues, implying it is required for replication, but that it is probably not associated with apoptosis induction, which occurs in infections of Spodoptera frugiperda ascovirus 1 a (SfAV-1a), the ascovirus type species. Other highly expressed viral genes at 48 h p.i. in viral vesicles included a dynein-like beta chain and lipid-modifying enzymes, suggesting their importance to vesicle formation and growth as well as virion synthesis. Finally, as occurs in SfAV expression, we found bicistronic and tricistronic mRNA messages produced by TnAV.
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Affiliation(s)
- Heba A H Zaghloul
- Interdepartmental Graduate Program in Microbiology and Institute for Integrative Genome Biology, Riverside Country, CA, USA.,Department of Botany and Microbiology, Faculty of Science, Alexandria University, Egypt
| | - Robert Hice
- Interdepartmental Graduate Program in Microbiology and Institute for Integrative Genome Biology, Riverside Country, CA, USA
| | - Peter Arensburger
- Department of Biological Sciences, California State Polytechnic University, Pomona, 3801 West Temple Avenue, Pomona CA 91768, USA
| | - Brian A Federici
- Interdepartmental Graduate Program in Microbiology and Institute for Integrative Genome Biology, Riverside Country, CA, USA.,Department of Entomology, University of California, Riverside, Riverside, CA 92521, USA
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3
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Liu S, Sappington TW, Coates BS, Bonning BC. Sequences Encoding a Novel Toursvirus Identified from Southern and Northern Corn Rootworms (Coleoptera: Chrysomelidae). Viruses 2022; 14:v14020397. [PMID: 35215990 PMCID: PMC8879594 DOI: 10.3390/v14020397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/07/2022] [Indexed: 02/05/2023] Open
Abstract
Sequences derived from a novel toursvirus were identified from pooled genomic short read data from U.S. populations of southern corn rootworm (SCR, Diabrotica undecimpunctata howardi Barber) and northern corn rootworm (NCR, Diabrotica barberi Smith & Lawrence). Most viral sequences were identified from the SCR genomic dataset. As proteins encoded by toursvirus sequences from SCR and NCR were almost identical, the contig sets from SCR and NCR were combined to generate 26 contigs. A total of 108,176 bp were assembled from these contigs, with 120 putative toursviral ORFs identified indicating that most of the viral genome had been recovered. These ORFs included all 40 genes that are common to members of the Ascoviridae. Two genes typically present in Ascoviridae (ATP binding cassette transport system permeases and Baculovirus repeated open reading frame), were not detected. There was evidence for transposon insertion in viral sequences at different sites in the two host species. Phylogenetic analyses based on a concatenated set of 45 translated protein sequences clustered toursviruses into a distinct clade. Based on the combined evidence, we propose taxonomic separation of toursviruses from Ascoviridae.
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Affiliation(s)
- Sijun Liu
- Department of Entomology, Iowa State University, Ames, IA 50011, USA;
| | - Thomas W. Sappington
- Corn Insects and Crop Genetics Research Unit, USDA-ARS, Ames, IA 50011, USA; (T.W.S.); (B.S.C.)
| | - Brad S. Coates
- Corn Insects and Crop Genetics Research Unit, USDA-ARS, Ames, IA 50011, USA; (T.W.S.); (B.S.C.)
| | - Bryony C. Bonning
- Department of Entomology and Nematology, University of Florida, Gainesville, FL 32611, USA
- Correspondence:
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4
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Zaghloul HAH, Hice RH, Arensburger P, Bideshi DK, Federici BA. Extended in vivo transcriptomes of two ascoviruses with different tissue tropisms reveal alternative mechanisms for enhancing virus reproduction in hemolymph. Sci Rep 2021; 11:16402. [PMID: 34385487 PMCID: PMC8361023 DOI: 10.1038/s41598-021-95553-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Ascoviruses are large dsDNA viruses characterized by the extraordinary changes they induce in cellular pathogenesis and architecture whereby after nuclear lysis and extensive hypertrophy, each cell is cleaved into numerous vesicles for virion reproduction. However, the level of viral replication and transcription in vesicles compared to other host tissues remains uncertain. Therefore, we applied RNA-Sequencing to compare the temporal transcriptome of Spodoptera frugiperda ascovirus (SfAV) and Trichoplusia ni ascovirus (TnAV) at 7, 14, and 21 days post-infection (dpi). We found most transcription occurred in viral vesicles, not in initial tissues infected, a remarkably novel reproduction mechanism compared to all other viruses and most other intracellular pathogens. Specifically, the highest level of viral gene expression occurred in hemolymph, for TnAV at 7 dpi, and SfAV at 14 dpi. Moreover, we found that host immune genes were partially down-regulated in hemolymph, where most viral replication occurred in highly dense accumulations of vesicles.
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Affiliation(s)
- Heba A H Zaghloul
- Interdepartmental Graduate Program in Microbiology and Institute for Integrative Genome Biology, Riverside, USA.,Department of Botany and Microbiology, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Robert H Hice
- Interdepartmental Graduate Program in Microbiology and Institute for Integrative Genome Biology, Riverside, USA
| | - Peter Arensburger
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA, 91768, USA
| | - Dennis K Bideshi
- Department of Biological Sciences, California Baptist University, Riverside, CA, 92504, USA
| | - Brian A Federici
- Interdepartmental Graduate Program in Microbiology and Institute for Integrative Genome Biology, Riverside, USA. .,Department of Entomology, University of California, Riverside, Riverside, CA, 92521, USA.
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5
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Nguyen M, Wemheuer B, Laffy PW, Webster NS, Thomas T. Taxonomic, functional and expression analysis of viral communities associated with marine sponges. PeerJ 2021; 9:e10715. [PMID: 33604175 PMCID: PMC7863781 DOI: 10.7717/peerj.10715] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/15/2020] [Indexed: 12/19/2022] Open
Abstract
Viruses play an essential role in shaping the structure and function of ecological communities. Marine sponges have the capacity to filter large volumes of ‘virus-laden’ seawater through their bodies and host dense communities of microbial symbionts, which are likely accessible to viral infection. However, despite the potential of sponges and their symbionts to act as viral reservoirs, little is known about the sponge-associated virome. Here we address this knowledge gap by analysing metagenomic and (meta-) transcriptomic datasets from several sponge species to determine what viruses are present and elucidate their predicted and expressed functionality. Sponges were found to carry diverse, abundant and active bacteriophages as well as eukaryotic viruses belonging to the Megavirales and Phycodnaviridae. These viruses contain and express auxiliary metabolic genes (AMGs) for photosynthesis and vitamin synthesis as well as for the production of antimicrobials and the defence against toxins. These viral AMGs can therefore contribute to the metabolic capacities of their hosts and also potentially enhance the survival of infected cells. This suggest that viruses may play a key role in regulating the abundance and activities of members of the sponge holobiont.
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Affiliation(s)
- Mary Nguyen
- Centre for Marine Science and Innovation & School of Biological & Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Bernd Wemheuer
- Centre for Marine Science and Innovation & School of Biological & Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Patrick W Laffy
- Australian Institute of Marine Science, Townsville, QLD, Australia
| | - Nicole S Webster
- Australian Institute of Marine Science, Townsville, QLD, Australia.,Australian Centre for Ecogenomics, University of Queensland, Brisbane, QLD, Australia
| | - Torsten Thomas
- Centre for Marine Science and Innovation & School of Biological & Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
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6
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He L, Ou-Yang YY, Li N, Chen Y, Liu SQ, Huang GH. Regulation of Chitinase in Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) During Infection by Heliothis virescens ascovirus 3h (HvAV-3h). Front Physiol 2020; 11:166. [PMID: 32210833 PMCID: PMC7077506 DOI: 10.3389/fphys.2020.00166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/12/2020] [Indexed: 11/13/2022] Open
Abstract
Insect chitinases play essential roles in the molting and metamorphosis of insects. The virus Heliothis virescens ascovirus 3h (HvAV-3h) can prolong the total duration of the larval stage in its host larvae. In this study, the molecular character and function of chitinase and chitin-binding domain (CBD) were analyzed in larvae of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). In detecting the chitinase activity of mock-infected and HvAV-3h-infected larval whole bodies and four different larval tissues, the results showed that larval chitinase activity was significantly decreased at 48 h post infection (hpi) and that the chitinase activity of HvAV-3h-infected larval fat body and cuticle was notably decreased at 144 and 168 hpi. The transcription level of S. exigua chitinase 7 (SeCHIT7) was down-regulated at the 6, 9, 12, 48, 72, and 96 hpi sample times, the S. exigua chitinase 11 (SeCHIT11) was down-regulated at 3-96 hpi, while both S. exigua chitinases (SeCHITs) were up-regulated at 120-168 hpi. Further tissue-specific detection of SeCHIT7 and SeCHIT11 transcription showed that SeCHIT7 was down-regulated at 144 and 168 hpi in the fat body and cuticle. SeCHIT11 was down-regulated at 168 hpi in the fat body, midgut, and cuticle. Additionally, the transcription and expression of S. exigua chitin-binding domain (SeCBD) could not be detected in HvAV-3h-infected larvae. The in vitro analyses of SeCHIT7N, SeCHIT11, and SeCBD showed that SeCHIT7N and SeCHIT11 were typical chitinases. Conversely, no chitinase activity was detected with SeCBD. SeCBD, however, could significantly increase the activity of SeCHIT7N and SeCHIT11. In conclusion, HvAV-3h not only interfered with the transcription and expression of SeCHITs but also affected the normal transcription and expression of SeCBD and, in doing so, influenced the host larval chitinase activity. These results will aid in providing a foundation for further studies on the pathogenesis of HvAV-3h.
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Affiliation(s)
- Lei He
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China.,College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Yi-Yi Ou-Yang
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China.,College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Ni Li
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China.,College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Ying Chen
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China.,College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Shuang-Qing Liu
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China.,College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Guo-Hua Huang
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China.,College of Plant Protection, Hunan Agricultural University, Changsha, China
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7
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Genome Analysis of Dasineura jujubifolia Toursvirus 2, A Novel Ascovirus. Virol Sin 2019; 35:134-142. [PMID: 31784872 DOI: 10.1007/s12250-019-00177-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/09/2019] [Indexed: 10/25/2022] Open
Abstract
So far, ascoviruses have only been identified from Lepidoptera host insects and their transmission vectors-endoparasitic wasps. Here, we reported the first finding of a complete novel ascovirus genome from a Diptera insect, Dasineura jujubifolia. Initially, sequence fragments with homology to ascoviruses were incidentally identified during metagenomic sequencing of the mitochondria of D. jujubifolia (Cecidomyiidae, Diptera) which is a major pest on Ziziphus jujuba. Then a full circular viral genome was assembled from the metagenomic data, which has an A+T percentage of 74% and contains 142,600 bp with 141 open reading frames (ORFs). Among the 141 ORFs, 37 were conserved in all sequenced ascoviruses (core genes) including proteins predicted to participate in DNA replication, gene transcription, protein modification, virus assembly, lipid metabolism and apoptosis. Multi-gene families including those encode for baculovirus repeated open reading frames (BROs), myristylated membrane proteins, RING/U-box E3 ubiquitin ligases, and ATP-binding cassette (ABC) transporters were found in the virus genome. Phylogenetic analysis showed that the newly identified virus belongs to genus Toursvirus of Ascoviridae, and is therefore named as Dasineura jujubifolia toursvirus 2 (DjTV-2a). The virus becomes the second reported species of the genus after Diadromus pulchellus toursvirus 1 (DpTV-1a). The genome arrangement of DjTV-2a is quite different from that of DpTV-1a, suggesting these two viruses separated in an early time of evolution. The results suggest that the ascoviruses may infect a much broader range of hosts than our previous knowledge, and shed lights on the evolution of ascoviruses and particularly on that of the toursviruses.
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8
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Zhao Y, Yu H, He L, Li N, Huang GH. 3H-117, a structural protein of Heliothis virescens ascovirus 3h (HvAV-3h). Virus Genes 2019; 55:688-695. [PMID: 31236766 DOI: 10.1007/s11262-019-01679-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 06/18/2019] [Indexed: 10/26/2022]
Abstract
The open reading frame 117 (3h-117) of Heliothis virescens ascovirus 3h (HvAV-3h), which is a conserved coding region present in all completely sequenced ascovirus members, was characterized in this study. By RT-PCR detection, 3h-117 transcription began at 6-h post-infection (hpi) and remained stable until 168 hpi in HvAV-3h-infected Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae. In addition, 3h-117 putatively encodes a 21.5-kDa protein (3H-117) predicted to be a CTD-like phosphatase. Western blot analysis using a prepared rabbit polyclonal antibody specific to 3H-117 showed that the product could be detected at 24 hpi, which remained stably detectable until 168 hpi. The same analysis also demonstrated that the 3H-117 protein localized in the virions of HvAV-3h. Immunofluorescence analysis showed that at 24 hpi, 3H-117 was mainly located in the nuclei of H. armigera larval fat body cells and later spread into the cytoplasm. In summary, our results indicate that 3H-117 is a structural protein of HvAV-3h.
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Affiliation(s)
- Ying Zhao
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Changsha, 410128, China.,College of Plant Protection, Hunan Agricultural University, Changsha, 410128, China
| | - Huan Yu
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Changsha, 410128, China.,College of Plant Protection, Hunan Agricultural University, Changsha, 410128, China
| | - Lei He
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Changsha, 410128, China.,College of Plant Protection, Hunan Agricultural University, Changsha, 410128, China
| | - Ni Li
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Changsha, 410128, China.,College of Plant Protection, Hunan Agricultural University, Changsha, 410128, China
| | - Guo-Hua Huang
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Changsha, 410128, China. .,College of Plant Protection, Hunan Agricultural University, Changsha, 410128, China.
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9
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Chen ZS, Hou DH, Cheng XW, Wang X, Huang GH. Genomic analysis of a novel isolate Heliothis virescens ascovirus 3i (HvAV-3i) and identification of ascoviral repeat ORFs (aros). Arch Virol 2018; 163:2849-2853. [PMID: 29948385 DOI: 10.1007/s00705-018-3899-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/12/2018] [Indexed: 01/08/2023]
Abstract
Ascoviruses are circular double-stranded DNA viruses that infect insects. Herein we sequenced and analyzed the genome of the previously unrecorded ascovirus isolate Heliothis virescens ascovirus 3i (HvAV-3i). The genome size is 185,650 bp with 181 hypothetical open reading frames (ORFs). Additionally, definition based on ascovirus repeated ORFs (aros) is proposed; whereby the 29 aros from all sequenced Ascoviridae genomes are divided into six distinct groups. The topological relationship among the isolates of Heliothis virescens ascovirus 3a is (HvAV-3f, {HvAV-3h, [HvAV-3e, (HvAV-3g, HvAV-3i)]}) with every clade well supported by a Bayesian posterior probability of 1.00 and a Bootstrap value of 100%.
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Affiliation(s)
- Zi-Shu Chen
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, 410128, Hunan, China
- Institute of Virology, College of Plant Protection, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Dian-Hai Hou
- School of Bioscience and Technology, Weifang Medical University, Weifang, 261053, Shandong, China
| | - Xiao-Wen Cheng
- Department of Microbiology, 56 Pearson Hall, Miami University, Oxford, 45056, Ohio, USA
| | - Xing Wang
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, 410128, Hunan, China
- Institute of Virology, College of Plant Protection, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Guo-Hua Huang
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, 410128, Hunan, China.
- Institute of Virology, College of Plant Protection, Hunan Agricultural University, Changsha, 410128, Hunan, China.
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10
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Arai E, Ishii K, Ishii H, Sagawa S, Makiyama N, Mizutani T, Omatsu T, Katayama Y, Kunimi Y, Inoue MN, Nakai M. An ascovirus isolated from Spodoptera litura (Noctuidae: Lepidoptera) transmitted by the generalist endoparasitoid Meteorus pulchricornis (Braconidae: Hymenoptera). J Gen Virol 2018. [DOI: 10.1099/jgv.0.001035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Eiko Arai
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Kazuo Ishii
- Biostatistics Center, University of Kurume, 67, Asahimachi, Kurume, Fukuoka 830-0011, Japan
| | - Hiroki Ishii
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Shiori Sagawa
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Nao Makiyama
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Tetsuya Mizutani
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Tsutomu Omatsu
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Yukie Katayama
- 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
| | - Maki N. Inoue
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
| | - Madoka Nakai
- Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan
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11
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Complete Genome Sequence of a Renamed Isolate, Trichoplusia ni Ascovirus 6b, from the United States. GENOME ANNOUNCEMENTS 2018. [PMID: 29519841 PMCID: PMC5843727 DOI: 10.1128/genomea.00148-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The complete genome of Trichoplusia ni ascovirus 6b (TnAV-6b) was sequenced for the first time. The TnAV-6b isolate, which has its closest phylogenetic relationship with the TnAV-6a isolate, has a circular genome of 185,664 bp, with a G+C content of 46.0% and 178 predicted open reading frames.
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12
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Genome analysis of Heliothis virescens ascovirus 3h isolated from China. Virol Sin 2017; 32:147-154. [PMID: 28382574 DOI: 10.1007/s12250-016-3929-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/15/2017] [Indexed: 10/19/2022] Open
Abstract
No ascovirus isolated from China has been sequenced so far. Therefore, in this study, we aimed to sequence the genome of Heliothis virescens ascovirus 3h (HvAV-3h) using the 454 pyrosequencing technology. The genome was found to be 190,519-bp long with a G+C content of 45.5%. We also found that it encodes 185 hypothetical open reading frames (ORFs) along with at least 50 amino acids, including 181 ORFs found in other ascoviruses and 4 unique ORFs. Gene-parity plots and phylogenetic analysis revealed a close relationship between HvAV-3h and three other HvAV-3a strains and a distant relationship with Spodoptera frugiperda ascovirus 1a (SfAV-1a), Trichoplusia ni ascovirus 6a (TnAV-6a), and Diadromus pulchellus ascovirus 4a (DpAV-4a). Among the 185 potential genes encoded by the genome, 44 core genes were found in all the sequenced ascoviruses. In addition, 25 genes were found to be conserved in all ascoviruses except DpAV-4a. In the HvAV-3h genome, 24 baculovirus repeat ORFs (bros) were present, and the typical homologous repeat regions (hrs) were absent. This study supplies information important for understanding the conservation and functions of ascovirus genes as well as the variety of ascoviral genomes.
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13
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Hammerl JA, Göllner C, Al Dahouk S, Nöckler K, Reetz J, Hertwig S. Analysis of the First Temperate Broad Host Range Brucellaphage (BiPBO1) Isolated from B. inopinata. Front Microbiol 2016; 7:24. [PMID: 26858702 PMCID: PMC4729917 DOI: 10.3389/fmicb.2016.00024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/11/2016] [Indexed: 11/13/2022] Open
Abstract
Brucella species are important human and animal pathogens. Though, only little is known about mobile genetic elements of these highly pathogenic bacteria. To date, neither plasmids nor temperate phages have been described in brucellae. We analyzed genomic sequences of various reference and type strains and identified a number of putative prophages residing within the Brucella chromosomes. By induction, phage BiPBO1 was isolated from Brucella inopinata. BiPBO1 is a siphovirus that infects several Brucella species including Brucella abortus and Brucella melitensis. Integration of the phage genome occurs adjacent to a tRNA gene in chromosome 1 (chr 1). The bacterial (attB) and phage (attP) attachment sites comprise an identical sequence of 46 bp. This sequence exists in many Brucella and Ochrobactrum species. The BiPBO1 genome is composed of a 46,877 bp double-stranded DNA. Eighty-seven putative gene products were determined, of which 32 could be functionally assigned. Strongest similarities were found to a temperate phage residing in the chromosome of Ochrobactrum anthropi ATCC 49188 and to prophages identified in several families belonging to the order rhizobiales. The data suggest that horizontal gene transfer may occur between Brucella and Ochrobactrum and underpin the close relationship of these environmental and pathogenic bacteria.
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Affiliation(s)
- Jens A. Hammerl
- Department of Biological Safety, Federal Institute for Risk AssessmentBerlin, Germany
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14
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Wei YL, Hu J, Li SJ, Chen ZS, Cheng XW, Huang GH. Genome sequence and organization analysis of Heliothis virescens ascovirus 3f isolated from a Helicoverpa zea larva. J Invertebr Pathol 2014; 122:40-3. [PMID: 25149038 DOI: 10.1016/j.jip.2014.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/04/2014] [Accepted: 08/12/2014] [Indexed: 10/24/2022]
Abstract
The complete genome sequence of Heliothis virescens ascovirus 3f (HvAV-3f) was obtained. The HvAV-3f genome has a circular genome of 198,157bp with a G+C content of 46.0%, and encodes 190 open reading frames (ORFs) longer than 69 amino acids. Two major homologous regions (hrs) and 29 'baculovirus repeat ORFs' (bro) were found in the genome. BLAST analyses revealed that three HvAV-3f genes were homologous to that of lepidopteran insects. Nine ORFs were unique to HvAV-3f, in which two ORFs showed significant levels of similarity to genes that have not been previously described for ascoviruses in the Genbank database.
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Affiliation(s)
- Yong-Lu Wei
- Institute of Virology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan 410128, China
| | - Jue Hu
- Institute of Virology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan 410128, China
| | - Shun-Ji Li
- Institute of Virology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan 410128, China
| | - Zi-Shu Chen
- Institute of Virology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan 410128, China
| | - Xiao-Wen Cheng
- Institute of Virology, Hunan Agricultural University, Changsha, Hunan 410128, China; Department of Microbiology, Miami University, 32 Pearson Hall, Oxford, OH 45056, USA.
| | - Guo-Hua Huang
- Institute of Virology, Hunan Agricultural University, Changsha, Hunan 410128, China; Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan 410128, China.
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15
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Rohrmann GF, Erlandson MA, Theilmann DA. The genome of a baculovirus isolated from Hemileuca sp. encodes a serpin ortholog. Virus Genes 2013; 47:357-64. [PMID: 23852342 DOI: 10.1007/s11262-013-0951-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 06/28/2013] [Indexed: 11/30/2022]
Abstract
The genome sequence of a baculovirus from Hemileuca sp. was determined. The genome is 140,633 kb, has a G+C content of 38.1 %, and encodes 137 putative open-reading frames over 50 amino acids. 126 of these ORFs showed similarity to other baculovirus genes in the database including all 37 core genes. Of the remaining 11 predicted genes, one is related to a lepidopteran serpin gene. This is the first report of a baculovirus encoding a member of this family of serine protease inhibitors, and to our knowledge the first report of a viral serpin outside the Poxviridae. The genome also contained three homologous repeat sequences. Phylogenetic analysis indicated that the virus is a group II Alphabaculovirus and belongs to a lineage that includes Orgyia leucostigma, Ectropis obliqua, Apocheima cinerarium, and Euproctis pseudoconspersa nucleopolyhedroviruses.
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Affiliation(s)
- George F Rohrmann
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331-3804, USA,
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16
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Genomic sequence of Heliothis virescens ascovirus 3g isolated from Spodoptera exigua. J Virol 2013; 86:12467-8. [PMID: 23087124 DOI: 10.1128/jvi.02342-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heliothis virescens ascovirus 3a (HvAV-3a), a member of the family Ascoviridae, has the highest diversity among ascovirus species that have been reported in Australia, Indonesia, China, and the United States. To understand the diversity and origin of this important ascovirus, the complete genome of the HvAV Indonesia strain (HvAV-3g), isolated from Spodoptera exigua, was determined to be 199,721 bp, with a G+C content of 45.9%. Therefore, HvAV-3g has the largest genome among the reported ascovirus genomes to date. There are 194 predicted open reading frames (ORFs) encoding proteins of 50 or more amino acid residues. In comparison to HvAV-3e reported from Australia, HvAV-3g has all the ORFs in HvAV-3e with 6 additional ORFs unique to HvAV-3g, including 1 peptidase C26 gene with the highest identity to Drosophila spp. and 2 gas vesicle protein U (GvpU) genes with identities to Bacillus megaterium. The five unique homologous regions (hrs) and 25 baculovirus repeat ORFs (bro) of HvAV-3g are highly variable.
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17
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Abstract
Hemolysins are a class of proteins defined by their ability to lyse red cells but have been described to exhibit pleiotropic functions. These proteins have been extensively studied in bacteria and more recently in fungi. Within the last decade, a number of studies have characterized fungal hemolysins and revealed a fascinating yet diverse group of proteins. The purpose of this review is to provide a synopsis of the known fungal hemolysins with an emphasis on those belonging to the aegerolysin protein family. New insight and perspective into fungal hemolysins in biotechnology and health are additionally presented.
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Affiliation(s)
- Ajay P Nayak
- Allergy and Clinical Immunology Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA.
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18
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Huang GH, Garretson TA, Cheng XH, Holztrager MS, Li SJ, Wang X, Cheng XW. Phylogenetic position and replication kinetics of Heliothis virescens ascovirus 3h (HvAV-3h) isolated from Spodoptera exigua. PLoS One 2012; 7:e40225. [PMID: 22792245 PMCID: PMC3390325 DOI: 10.1371/journal.pone.0040225] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 06/03/2012] [Indexed: 11/18/2022] Open
Abstract
Insect-specific ascoviruses with a circular genome are distributed in the USA, France, Australia and Indonesia. Here, we report the first ascovirus isolation from Spodoptera exigua in Hunan, China. DNA-DNA hybridization to published ascoviruses demonstrated that the new China ascovirus isolate is a variant of Heliothis virescens ascovirus 3a (HvAV-3a), thus named HvAV-3h. We investigated the phylogenetic position, cell infection, vesicle production and viral DNA replication kinetics of HvAV-3h, as well as its host-ranges. The major capsid protein (MCP) gene and the delta DNA polymerase (DNA po1) gene of HvAV-3h were sequenced and compared with the available ascovirus isolates for phylogenetic analysis. This shows a close relationship with HvAV-3g, originally isolated from Indonesia, HvAV-3e from Australia and HvAV-3c from United States. HvAV-3h infection induced vesicle production in the SeE1 cells derived from S. exigua and Sf9 cells derived from S. frugiperda, resulting in more vesicles generated in Sf9 than SeE1. Viral DNA replication kinetics of HvAV-3h also demonstrated a difference between the two cell lines tested. HvAV-3h could readily infect three important insect pests Helicoverpa armigera (Hübner), Spodoptera exigua (Hübner) and Spodoptera litura (Fabricius) from two genera in different subfamilies with high mortalities.
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Affiliation(s)
- Guo-Hua Huang
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan, China
| | - Tyler A. Garretson
- . Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Xin-Hua Cheng
- . Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Maria S. Holztrager
- . Department of Microbiology, Miami University, Oxford, Ohio, United States of America
| | - Shun-Ji Li
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan, China
| | - Xing Wang
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan, China
| | - Xiao-Wen Cheng
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan, China
- . Department of Microbiology, Miami University, Oxford, Ohio, United States of America
- * E-mail:
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19
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Xue JL, Cheng XW. Comparative analysis of a highly variable region within the genomes of Spodoptera frugiperda ascovirus 1d (SfAV-1d) and SfAV-1a. J Gen Virol 2011; 92:2797-2802. [DOI: 10.1099/vir.0.035733-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recently discovered ascoviruses have a worldwide distribution. Here we report a new member of the family Ascoviridae, Spodoptera frugiperda ascovirus 1d (SfAV-1d) with a variable region in the genome. Restriction fragment length polymorphism, Southern hybridization and genome sequencing analyses confirmed that SfAV-1d and the earlier reported SfAV-1a are closely related but are not identical. The genome size of SfAV-1d is approximately 100 kbp, which is about 57 kbp smaller than SfAV-1a. The SfAV-1d genome has a major deletion of 14 kbp that corresponds to one of the inverted repeat (IR) regions of SfAV-1a. Cloning and sequencing revealed that the region flanking the deletion within the SfAV-1d genome is highly variable. In all the variants of this region, the whole IR region is missing, with 88.2 % of the variants missing part of or the whole adjacent SfAV-1a ORF71, 94.1 % missing part of or the whole of adjacent ORF72 and 64.6 % missing part of or the whole of ORF73.
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Affiliation(s)
- Jian-Li Xue
- Department of Microbiology, 32 Pearson Hall, Miami University, Oxford, OH 45056, USA
| | - Xiao-Wen Cheng
- Department of Microbiology, 32 Pearson Hall, Miami University, Oxford, OH 45056, USA
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20
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Zhang S, Clark KD, Strand MR. The protein P23 identifies capsule-forming plasmatocytes in the moth Pseudoplusia includens. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:501-510. [PMID: 21167864 DOI: 10.1016/j.dci.2010.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Revised: 12/07/2010] [Accepted: 12/08/2010] [Indexed: 05/30/2023]
Abstract
The moth Pseudoplusia includens produces four types of hemocytes named granulocytes, plasmatocytes, spherule cells and oenocytoids. Prior studies established that the main function of plasmatocytes in P. includens is encapsulation of parasitoids and other foreign entitites. P. includens plasmatocytes are also recognized by several monoclonal antibodies that bind unknown antigens. Of particular interest is the antibody 43E9A10 whose binding properties indicate that plasmatocytes consist of two subpopulations: cells that can spread on foreign surfaces and cells that cannot. Here we report 43E9A10 recognizes P23, which is a member of the aegerolysin protein family. Expression analyses confirmed that p23 is specifically expressed in plasmatocytes. Functional studies indicated that only P23-expressing plasmatocytes form capsules and spread in response to the cytokine plasmatocyte spreading peptide. In contrast, P23 showed no antibacterial or cytolytic activity toward bacteria and mammalian erythrocytes. Overall, our results suggest that P23 is a maturation marker that identifies capsule-forming plasmatocytes.
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Affiliation(s)
- Shu Zhang
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
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21
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Ince IA, Boeren SA, van Oers MM, Vervoort JJM, Vlak JM. Proteomic analysis of Chilo iridescent virus. Virology 2010; 405:253-8. [PMID: 20598335 PMCID: PMC7111926 DOI: 10.1016/j.virol.2010.05.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/06/2010] [Accepted: 05/28/2010] [Indexed: 01/01/2023]
Abstract
In this first proteomic analysis of an invertebrate iridovirus, 46 viral proteins were detected in the virions of Chilo iridescent virus (CIV) based on the detection of 2 or more distinct peptides; an additional 8 proteins were found based on a single peptide. Thirty-six of the 54 identified proteins have homologs in another invertebrate and/or in one or more vertebrate iridoviruses. The genes for 5 of the identified proteins, 22L (putative helicase), 118L, 142R (putative RNaseIII), 274L (major capsid protein) and 295L, are shared by all iridoviruses for which the complete nucleotide sequence is known and may therefore be considered as iridovirus core genes. Three identified proteins have homologs only in ascoviruses. The remaining 15 identified proteins are so far unique to CIV. In addition to broadening our insight in the structure and assembly of CIV virions, this knowledge is pivotal to unravel the initial steps in the infection process.
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Affiliation(s)
- Ikbal Agah Ince
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
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22
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An Ascovirus-encoded RNase III autoregulates its expression and suppresses RNA interference-mediated gene silencing. J Virol 2010; 84:3624-30. [PMID: 20071573 DOI: 10.1128/jvi.02362-09] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNase III proteins play vital roles in processing of several types of RNA molecules and gene silencing. Recently, it has been discovered that some plant and animal viruses encode RNase III-like proteins as well. Genome sequencing of four virus species belonging to the Ascoviridae family has revealed sequence conservation of an RNase III open reading frame among the viruses. These have not been explored in ascoviruses, and therefore their role in host-virus interaction is unknown. Here, we confirmed expression of Heliothis virescens ascovirus (HvAV-3e) open reading frame 27 (orf27) that encodes an RNase III-like protein after infection and demonstrated dsRNA specific endoribonuclease activity of the encoded protein. Analysis of the expression patterns of orf27 in virus-infected insect cells and a bacterial expression system revealed autoregulation of this protein over time. Moreover, HvAV-3e RNase III was found essential for virus DNA replication and infection using RNA interference (RNAi)-mediated gene silencing. In addition, using green fluorescent protein gene as a marker, we provide evidence that RNase III is involved in the suppression of gene silencing. To our knowledge, this is the first insect virus-encoded RNase III described and shown to suppress host cell RNAi defense mechanism.
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23
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Hussain M, Asgari S. Functional analysis of a cellular microRNA in insect host-ascovirus interaction. J Virol 2010; 84:612-20. [PMID: 19846520 PMCID: PMC2798455 DOI: 10.1128/jvi.01794-09] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 10/13/2009] [Indexed: 12/21/2022] Open
Abstract
MicroRNAs (miRNAs) have emerged as key regulators in many biological processes, from development to defense, at almost all organismal levels. Recently, their role has been highlighted in pathogen-host interactions. Emerging evidence from a variety of virus-host systems indicates that cellular as well as virally encoded miRNAs influence viral replication. Here, we report changes in expression levels of host miRNAs upon ascovirus infection in an insect cell line and investigated the role of a host miRNA, Hz-miR24, in the host-virus system. We found that Hz-miR24 is differentially expressed following virus infection, with an increase in its expression levels late in infection. Experimental evidence demonstrated that Hz-miR24 downregulates ascoviral DNA-dependent RNA polymerase and its beta subunit transcript levels late in infection. The specific miRNA-target interactions were investigated and confirmed using the ectopic expression of Hz-miR24 and a green fluorescent protein-based reporter system. Further, the expression of the target gene was substantially enhanced in cells transfected with a synthesized inhibitor of Hz-miR24. These findings suggest that ascoviruses manipulate host miRNAs that in turn regulate the expression of their genes at specific time points after infection. To our knowledge, this is the first cellular miRNA reported to interact with an insect virus.
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Affiliation(s)
- Mazhar Hussain
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Sassan Asgari
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia
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24
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A lipase-like gene from Heliothis virescens ascovirus (HvAV-3e) is essential for virus replication and cell cleavage. Virus Genes 2009; 39:409-17. [PMID: 19821020 DOI: 10.1007/s11262-009-0407-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 09/26/2009] [Indexed: 10/20/2022]
Abstract
A unique feature of ascovirus infection is cleavage of host cells into virus containing vesicles. It has been suggested that the virus induces apoptosis, either by expression of a caspase or other means, which is then diverted toward vesicle formation. There is little known about the mechanism of vesicle formation. Recent genome sequences of three ascoviruses indicated the presence of several putative open reading frames coding for proteins that could be involved in lipid metabolism. These proteins may play a role in rearrangement of membranes in infected host cells leading to formation of vesicles. Here, we analyzed a lipase-like gene (ORF19) from Heliothis virescens ascovirus (HvAV-3e) expressed from 8 h after infection and essential for virus replication and cell cleavage. In addition, ORF19 knock down by RNA interference inhibited virus replication indicating that the gene is indispensable for HvAV-3e replication. However, under enzymatic assays tested, we did not detect any lipase or esterase activity from ORF19.
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25
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Hussain M, Garrad S, Asgari S. The role of actin filaments in ascovirus replication and pathology. Arch Virol 2009; 154:1737-43. [DOI: 10.1007/s00705-009-0512-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 09/02/2009] [Indexed: 10/25/2022]
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26
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Bigot Y, Renault S, Nicolas J, Moundras C, Demattei MV, Samain S, Bideshi DK, Federici BA. Symbiotic virus at the evolutionary intersection of three types of large DNA viruses; iridoviruses, ascoviruses, and ichnoviruses. PLoS One 2009; 4:e6397. [PMID: 19636425 PMCID: PMC2712680 DOI: 10.1371/journal.pone.0006397] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 05/31/2009] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The ascovirus, DpAV4a (family Ascoviridae), is a symbiotic virus that markedly increases the fitness of its vector, the parasitic ichneumonid wasp, Diadromus puchellus, by increasing survival of wasp eggs and larvae in their lepidopteran host, Acrolepiopsis assectella. Previous phylogenetic studies have indicated that DpAV4a is related to the pathogenic ascoviruses, such as the Spodoptera frugiperda ascovirus 1a (SfAV1a) and the lepidopteran iridovirus (family Iridoviridae), Chilo iridescent virus (CIV), and is also likely related to the ancestral source of certain ichnoviruses (family Polydnaviridae). METHODOLOGY/PRINCIPAL FINDINGS To clarify the evolutionary relationships of these large double-stranded DNA viruses, we sequenced the genome of DpAV4a and undertook phylogenetic analyses of the above viruses and others, including iridoviruses pathogenic to vertebrates. The DpAV4a genome consisted of 119,343 bp and contained at least 119 open reading frames (ORFs), the analysis of which confirmed the relatedness of this virus to iridoviruses and other ascoviruses. CONCLUSIONS Analyses of core DpAV4a genes confirmed that ascoviruses and iridoviruses are evolutionary related. Nevertheless, our results suggested that the symbiotic DpAV4a had a separate origin in the iridoviruses from the pathogenic ascoviruses, and that these two types shared parallel evolutionary paths, which converged with respect to virion structure (icosahedral to bacilliform), genome configuration (linear to circular), and cytopathology (plasmalemma blebbing to virion-containing vesicles). Our analyses also revealed that DpAV4a shared more core genes with CIV than with other ascoviruses and iridoviruses, providing additional evidence that DpAV4a represents a separate lineage. Given the differences in the biology of the various iridoviruses and ascoviruses studied, these results provide an interesting model for how viruses of different families evolved from one another.
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Affiliation(s)
- Yves Bigot
- Génétique, Immmunothérapie, Chimie et Cancer, UMR CNRS 6239, Université François Rabelais de Tours, UFR des Sciences et Techniques, Parc de Grandmont, Tours, France.
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27
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Berne S, Lah L, Sepčić K. Aegerolysins: structure, function, and putative biological role. Protein Sci 2009; 18:694-706. [PMID: 19309687 PMCID: PMC2762582 DOI: 10.1002/pro.85] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 01/19/2009] [Accepted: 01/26/2009] [Indexed: 12/13/2022]
Abstract
Aegerolysins, discovered in fungi, bacteria and plants, are highly similar proteins with interesting biological properties. Certain aegerolysins possess antitumoral, antiproliferative, and antibacterial activities. Further possible medicinal applications include their use in the prevention of atherosclerosis, or as vaccines. Additional biotechnological value of fungal aegerolysins lies in their involvement in development, which could improve cultivation of commercially important edible mushrooms. Besides, new insights on microheterogeneity of raft-like membrane domains could be gained by using aegerolysins as specific markers in cell and molecular biology. Although the exact function of aegerolysins in their producing organisms remains to be explained, they are biochemically well characterized all-beta structured proteins sharing the following common features: low isoelectric points, similar molecular weights (15-17 kDa), and stability in a wide pH range.
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Affiliation(s)
- Sabina Berne
- Medical Centre for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana1000 Ljubljana, Slovenia
| | - Ljerka Lah
- Ljerka Lah, Laboratory for Biosynthesis and Biotransformation, National Institute of Chemistry1000 Ljubljana, Slovenia
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana1000 Ljubljana, Slovenia
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28
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Tan Y, Bideshi DK, Johnson JJ, Bigot Y, Federici BA. Proteomic analysis of the Spodoptera frugiperda ascovirus 1a virion reveals 21 proteins. J Gen Virol 2009; 90:359-365. [PMID: 19141444 DOI: 10.1099/vir.0.005934-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Spodoptera frugiperda ascovirus 1a (SfAV-1a) is a double-stranded DNA virus that attacks lepidopteran larvae, in which it produces enveloped virions with complex symmetry which have an average diameter of 130 nm and length of 400 nm. Here, we report identification of 21 SfAV-1a-encoded proteins that occur in the virion, as determined by nano-liquid chromatography/tandem mass spectrometry. These included a helicase (ORF009), nuclease (ORF075), ATPase (ORF047), serine/threonine-like protein kinase (ORF064), inhibitor of apoptosis-like protein (ORF015), thiol oxidoreductase-like protein (ORF061), CTD phosphatase (ORF109), major capsid protein (ORF041) and a highly basic protein, P64 (ORF048). The latter two were the most abundant. Apart from ascoviruses, the closest orthologues were found in iridoviruses, providing further evidence that ascoviruses evolved from invertebrate iridoviruses. These results establish a foundation for investigating how ascovirus virion proteins interact to form their complex asymmetrical structure, as well as for elucidating the mechanisms involved in SfAV-1a virion morphogenesis.
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Affiliation(s)
- Yeping Tan
- Department of Entomology, University of California, Riverside, Riverside, CA 92521, USA
| | - Dennis K Bideshi
- California Baptist University, Department of Natural and Mathematical Sciences, 8432 Magnolia Avenue Riverside, CA 92504, USA.,Department of Entomology, University of California, Riverside, Riverside, CA 92521, USA
| | - Jeffrey J Johnson
- Department of Entomology, University of California, Riverside, Riverside, CA 92521, USA
| | - Yves Bigot
- CHRU de Tours, Université Francois Rabelais, UFR des Sciences & Techniques, Parc de Grandmont, 37200 Tours, France.,CNRS, UMR 6239, Génétique, Immunothérapie, Chimie et Cancer, Université Francois Rabelais, UFR des Sciences & Techniques, Parc de Grandmont, 37200 Tours, France
| | - Brian A Federici
- Interdepartmental Graduate Programs in Genetics and Cell, Molecular & Developmental Biology, University of California Riverside, Riverside, CA 92521, USA.,Department of Entomology, University of California, Riverside, Riverside, CA 92521, USA
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29
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P64, a novel major virion DNA-binding protein potentially involved in condensing the Spodoptera frugiperda Ascovirus 1a genome. J Virol 2009; 83:2708-14. [PMID: 19129454 DOI: 10.1128/jvi.01610-08] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We recently identified 21 structural proteins in the virion of Spodoptera frugiperda ascovirus 1a (SfAV1a), a virus with a large, double-stranded DNA genome of 157 kbp, which attacks species of the lepidopteran family Noctuidae. The two most abundant virion proteins were the major capsid protein and a novel protein (P64) of 64 kDa that contained two distinct domains not known previously to occur together. The amino-terminal half of P64 (residues 1 to 263) contained four repeats (a recently recognized motif with an unknown function) of a virus-specific two-cysteine adaptor. Adjoined to this, the carboxy-terminal half of P64 (residues 279 to 455) contained 14 copies of a highly basic, tandemly repeated motif rich in arginine and serine, having an 11- to 13-amino-acid consensus sequence, SPSQRRSTS(V/K)(A/S)RR, yielding a predicted isoelectric point of 12.2 for this protein. In the present study, we demonstrate by Southwestern analysis that SfAV1a P64 was the only virion structural protein that bound DNA. Additional electrophoretic mobility shift assays showed that P64 bound SfAV1a as well as non-SfAV1a DNA. Furthermore, we show through immunogold labeling of ultrathin sections that P64 is a component of virogenic stroma and appears to be progressively incorporated into the SfAV1a DNA core during virion assembly. As no other virion structural protein bound DNA and no basic DNA-binding proteins of lower mass are encoded by the SfAV1a genome or were identified by proteomic analysis, our results suggest that P64's function is to condense the large genome of this virus and assist in packaging this genome into its virion.
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30
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Ascoviruses: superb manipulators of apoptosis for viral replication and transmission. Curr Top Microbiol Immunol 2009; 328:171-96. [PMID: 19216438 DOI: 10.1007/978-3-540-68618-7_5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ascoviruses are members of a recently described new family (Ascoviridae) of large double-stranded DNA viruses that attack immature stages of insects belonging to the order Lepidoptera, in which they cause a chronic, fatal disease. Ascoviruses have several unusual characteristics not found among other viruses, the most novel of which are their transmission by endoparasitic wasps and a unique cytopathology that resembles apoptosis. Cell infection induces apoptosis and in some species is associated with synthesis of a virus-encoded executioner caspase and several lipid-metabolizing enzymes. Rather than leading directly to cell death, synthesis of viral proteins results in the rescue of developing apoptotic bodies that are converted into large vesicles in which virions accumulate and continue to assemble. In infected larvae, millions of these virion-containing vesicles begin to disperse from infected tissues 48-72 h after infection into the blood, making it milky white, a major characteristic of the disease. Circulation of virions and vesicles in the blood facilitates mechanical transmission by parasitic wasps. Although ascoviruses appear to be very common, only five species are currently recognized, with the type species being the Spodoptera frugiperda ascovirus 1a. Ascovirus virions are large, enveloped, typically bacilliform or reniform in shape, and, depending on the species, have genomes that range from 119 to 186 kbp. Molecular phylogenetic evidence indicates that ascoviruses evolved from iridoviruses (family Iridoviridae) that attack lepidopteran larvae and are likely the evolutionary source of ichnoviruses (family Polydnaviridae), which assist endoparasitic hymenopterans in overcoming the defense responses of their insect hosts. Thus, as other molecular evidence suggests that iridoviruses evolved from phycodnaviruses (family Phycodnaviridae), an evolutionary pathway is apparent from phycodnaviruses via iridoviruses and ascoviruses to ichnoviruses.
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Hussain M, Asgari S. Inhibition of apoptosis by Heliothis virescens ascovirus (HvAV-3e): characterization of orf28 with structural similarity to inhibitor of apoptosis proteins. Apoptosis 2008; 13:1417-26. [PMID: 18853258 DOI: 10.1007/s10495-008-0268-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Ascoviruses (AVs) induce a unique pathology in their insect host cells causing cleavage of the cells into virion-containing vesicles. The mechanism by which AVs induce vesicle formation is poorly understood. It is postulated that the virus initially induces apoptosis leading to cell fragmentation. The apoptotic bodies are however, rescued by the virus to form the vesicles. Here we show that Heliothis virescens AV (HvAV-3e) is able to inhibit chemically induced apoptosis from around 16 h after infection. Analysis of the genome of the virus indicated the presence of a putative inhibitor of apoptosis (orf28) gene that encodes a protein with an imperfect baculovirus inhibitor of apoptosis repeat (BIR) and a RING domain. Transiently expressed orf28 did not inhibit chemically induced apoptosis suggesting that the protein may not serve as an inhibitor of apoptosis. Nevertheless, RNA interference studies revealed that the gene is probably essential for virus pathology and replication.
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Affiliation(s)
- Mazhar Hussain
- School of Integrative Biology, University of Queensland, St. Lucia, QLD 4072, Australia
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Bigot Y, Samain S, Augé-Gouillou C, Federici BA. Molecular evidence for the evolution of ichnoviruses from ascoviruses by symbiogenesis. BMC Evol Biol 2008; 8:253. [PMID: 18801176 PMCID: PMC2567993 DOI: 10.1186/1471-2148-8-253] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 09/18/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Female endoparasitic ichneumonid wasps inject virus-like particles into their caterpillar hosts to suppress immunity. These particles are classified as ichnovirus virions and resemble ascovirus virions, which are also transmitted by parasitic wasps and attack caterpillars. Ascoviruses replicate DNA and produce virions. Polydnavirus DNA consists of wasp DNA replicated by the wasp from its genome, which also directs particle synthesis. Structural similarities between ascovirus and ichnovirus particles and the biology of their transmission suggest that ichnoviruses evolved from ascoviruses, although molecular evidence for this hypothesis is lacking. RESULTS Here we show that a family of unique pox-D5 NTPase proteins in the Glypta fumiferanae ichnovirus are related to three Diadromus pulchellus ascovirus proteins encoded by ORFs 90, 91 and 93. A new alignment technique also shows that two proteins from a related ichnovirus are orthologs of other ascovirus virion proteins. CONCLUSION Our results provide molecular evidence supporting the origin of ichnoviruses from ascoviruses by lateral transfer of ascoviral genes into ichneumonid wasp genomes, perhaps the first example of symbiogenesis between large DNA viruses and eukaryotic organisms. We also discuss the limits of this evidence through complementary studies, which revealed that passive lateral transfer of viral genes among polydnaviral, bacterial, and wasp genomes may have occurred repeatedly through an intimate coupling of both recombination and replication of viral genomes during evolution. The impact of passive lateral transfers on evolutionary relationships between polydnaviruses and viruses with large double-stranded genomes is considered in the context of the theory of symbiogenesis.
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Affiliation(s)
- Yves Bigot
- Université François Rabelais de Tours, GICC, UFR des Sciences & Techniques, Parc de Grandmont, 37200 Tours, France.
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Harrison RL, Popham HJR. Genomic sequence analysis of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera. Virus Genes 2008; 36:565-81. [PMID: 18418706 DOI: 10.1007/s11262-008-0218-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 02/28/2008] [Indexed: 11/26/2022]
Abstract
The genome of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera, was completely sequenced. The size of the Helicoverpa armigera granulovirus (HearGV) genome is 169,794 nt containing 179 open reading frames (ORFs), making it the second largest baculovirus genome analyzed to date. The genomes of HearGV and the Xestia c-nigrum GV (XecnGV) exhibit extensive sequence similarity and co-linearity, with both genomes containing the same nine homologous regions (hrs) with conserved structure and locations and sharing 167 open reading frames (ORFs). Phylogenetic inference and pairwise analysis of Kimura-2-parameter nucleotide distances for the lef-8, lef-9, and granulin genes indicate that HearGV is part of a cluster of granuloviruses typified by XecnGV. The HearGV genome contains all 62 ORFs found in common among other fully sequenced lepidopteran baculovirus genomes, as well as seven ORFs unique to HearGV. In addition, HearGV and XecnGV genomes share 20 ORFs not found among other baculovirus genomes sequenced to date. In addition to possessing ten ORFs with sequence similarity to baculovirus repeated ORFs (bro), the HearGV genome contains members of two other gene families with homologues in ascovirus, nucleopolyhedrovirus, and entomopoxvirus genomes. Alignment of the HearGV and XecnGV genome sequences revealed that HearGV is missing approximately 16.6 kbp of XecnGV-homologous sequence and contains approximately 8.2 kbp of sequence not found in the XecnGV genome.
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Affiliation(s)
- Robert L Harrison
- Invasive Insect Biocontrol and Behavior Laboratory, Plant Sciences Institute, USDA, Agricultural Research Service, Building 011A, Room 214, BARC-W, 10300 Baltimore Avenue, Beltsville, MD 20705, USA.
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Genome analysis of a Glossina pallidipes salivary gland hypertrophy virus reveals a novel, large, double-stranded circular DNA virus. J Virol 2008; 82:4595-611. [PMID: 18272583 DOI: 10.1128/jvi.02588-07] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several species of tsetse flies can be infected by the Glossina pallidipes salivary gland hypertrophy virus (GpSGHV). Infection causes salivary gland hypertrophy and also significantly reduces the fecundity of the infected flies. To better understand the molecular basis underlying the pathogenesis of this unusual virus, we sequenced and analyzed its genome. The GpSGHV genome is a double-stranded circular DNA molecule of 190,032 bp containing 160 nonoverlapping open reading frames (ORFs), which are distributed equally on both strands with a gene density of one per 1.2 kb. It has a high A+T content of 72%. About 3% of the GpSGHV genome is composed of 15 sequence repeats, distributed throughout the genome. Although sharing the same morphological features (enveloped rod-shaped nucleocapsid) as baculoviruses, nudiviruses, and nimaviruses, analysis of its genome revealed that GpSGHV differs significantly from these viruses at the level of its genes. Sequence comparisons indicated that only 23% of GpSGHV genes displayed moderate homologies to genes from other invertebrate viruses, principally baculoviruses and entomopoxviruses. Most strikingly, the GpSGHV genome encodes homologues to the four baculoviral per os infectivity factors (p74 [pif-0], pif-1, pif-2, and pif-3). The DNA polymerase encoded by GpSGHV is of type B and appears to be phylogenetically distant from all DNA polymerases encoded by large double-stranded DNA viruses. The majority of the remaining ORFs could not be assigned by sequence comparison. Furthermore, no homologues to DNA-dependent RNA polymerase subunits were detected. Taken together, these data indicate that GpSGHV is the prototype member of a novel group of insect viruses.
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Transcriptional analysis of a major capsid protein gene from Spodoptera exigua ascovirus 5a. Arch Virol 2007; 153:149-62. [PMID: 17978884 DOI: 10.1007/s00705-007-1081-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Accepted: 09/17/2007] [Indexed: 10/22/2022]
Abstract
The major capsid protein (mcp) gene of Spodoptera exigua ascovirus 5a (SeAV-5a) was confirmed by aphidicolin viral DNA replication inhibition analysis to be a late gene. The 5' and 3' ends of mcp gene transcripts have been mapped. Primer extension analyses indicated that transcription of the mcp gene initiates from a cytosine 25 nucleotides (nt) upstream of the translation start codon. Two independent approaches by 3' rapid amplification of cDNA ends (3' RACE) and oligo (dT) cellulose binding assay suggested that SeAV-5a mcp mRNA is polyadenylated. Analyses by 3' RACE also revealed that mcp transcripts terminate at a U, either at 26 or 38 nt downstream of the translation stop codon. The putative 5' transcription control region of the SeAV-5a mcp gene shares similarities with other ascoviruses and Chilo iridescent virus (CIV), containing a conserved TATA-box-like motif (TAATTAAA) and an ATTTGATCTT motif upstream of it. The 3' downstream regions of the mcp gene of all the ascoviruses examined and CIV can form a stem-loop structure, and the ends of the mcp gene transcripts of SeAV-5a are within the predicted stem-loop region. This suggests that the stem-loop structure of the mcp gene might be involved in transcription termination.
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Cui L, Cheng X, Li L, Li J. Identification of Trichoplusia ni ascovirus 2c virion structural proteins. J Gen Virol 2007; 88:2194-2197. [PMID: 17622622 DOI: 10.1099/vir.0.82951-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ascoviruses are a family of insect viruses with circular, double-stranded DNA genomes. With the sequencing of the Trichoplusia ni ascovirus 2c (TnAV-2c) genome, the virion structural proteins were identified by using tandem mass spectrometry. From at least eight protein bands visible on a Coomassie blue-stained gel of TnAV-2c virion proteins, seven bands generated protein sequences that matched predicted open reading frames (ORFs) in the genome, i.e. ORFs 2, 43, 115, 141, 142, 147 and 153. Among these ORFs, only ORF153, encoding the major capsid protein, has been characterized previously.
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Affiliation(s)
- Liwang Cui
- Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, PA 16802, USA
| | - Xiaowen Cheng
- Department of Microbiology, 32 Pearson Hall, Miami University, Oxford, OH 45056, USA
| | - Lianchao Li
- Proteomics and Mass Spectrometry Core Facility, Huck Institutes of the Life Sciences, The Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802, USA
| | - Jianyong Li
- Department of Biochemistry, Virginia Polytechnic Institute and State University, 111 Engel Hall, Blacksburg, VA 24061, USA
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Asgari S. A caspase-like gene from Heliothis virescens ascovirus (HvAV-3e) is not involved in apoptosis but is essential for virus replication. Virus Res 2007; 128:99-105. [PMID: 17521762 DOI: 10.1016/j.virusres.2007.04.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 04/16/2007] [Accepted: 04/16/2007] [Indexed: 10/23/2022]
Abstract
Ascoviruses (AVs) are double-stranded DNA viruses causing a fatal disease in lepidopteran host larvae. A unique feature of AV infection is cleavage of host cells into membrane bound vesicles containing the virions. A recent study showed that a caspase from Spodoptera frugiperda AV (SfAV) is directly involved in initiation of apoptosis and eventually cell cleavage. Results shown here indicate that Heliothis virescens AV does not induce apoptosis in host cells. HvAV codes for a caspase-like protein but no apoptosis was observed when the gene was expressed in vitro. RNAi studies indicated that the gene is essential for virus replication.
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Affiliation(s)
- Sassan Asgari
- School of Integrative Biology, University of Queensland, St. Lucia, Qld 4072, Australia.
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Asgari S, Davis J, Wood D, Wilson P, McGrath A. Sequence and organization of the Heliothis virescens ascovirus genome. J Gen Virol 2007; 88:1120-1132. [PMID: 17374755 DOI: 10.1099/vir.0.82651-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nucleotide sequence of the Heliothis virescens ascovirus (HvAV-3e) DNA genome was determined and characterized in this study. The circular genome consists of 186,262 bp, has a G+C content of 45.8 mol% and encodes 180 potential open reading frames (ORFs). Five unique homologous regions (hrs), 23 'baculovirus repeat ORFs' (bro) and genes encoding a caspase homologue and several enzymes involved in nucleotide replication and metabolism were found in the genome. Several ascovirus (AV)-, iridovirus- and baculovirus-homologous genes were identified. The genome is significantly larger than the recently sequenced genomes of Trichoplusia ni AV (TnAV-2c) and Spodoptera frugiperda AV (SfAV-1a). Gene-parity plots and overall similarity of ORFs indicate that HvAV-3e is related more closely to SfAV-1a than to TnAV-2c.
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Affiliation(s)
- Sassan Asgari
- School of Integrative Biology, University of Queensland, St Lucia, QLD 4072, Australia
| | - John Davis
- Australian Genome Research Facility, University of Queensland, St Lucia, QLD 4072, Australia
| | - David Wood
- Australian Genome Research Facility, University of Queensland, St Lucia, QLD 4072, Australia
| | - Peter Wilson
- Australian Genome Research Facility, University of Queensland, St Lucia, QLD 4072, Australia
| | - Annette McGrath
- Australian Genome Research Facility, University of Queensland, St Lucia, QLD 4072, Australia
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Bideshi DK, Demattei MV, Rouleux-Bonnin F, Stasiak K, Tan Y, Bigot S, Bigot Y, Federici BA. Genomic sequence of Spodoptera frugiperda Ascovirus 1a, an enveloped, double-stranded DNA insect virus that manipulates apoptosis for viral reproduction. J Virol 2006; 80:11791-805. [PMID: 16987980 PMCID: PMC1642580 DOI: 10.1128/jvi.01639-06] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ascoviruses (family Ascoviridae) are double-stranded DNA viruses with circular genomes that attack lepidopterans, where they produce large, enveloped virions, 150 by 400 nm, and cause a chronic, fatal disease with a cytopathology resembling that of apoptosis. After infection, host cell DNA is degraded, the nucleus fragments, and the cell then cleaves into large virion-containing vesicles. These vesicles and virions circulate in the hemolymph, where they are acquired by parasitic wasps during oviposition and subsequently transmitted to new hosts. To develop a better understanding of ascovirus biology, we sequenced the genome of the type species Spodoptera frugiperda ascovirus 1a (SfAV-1a). The genome consisted of 156,922 bp, with a G+C ratio of 49.2%, and contained 123 putative open reading frames coding for a variety of enzymes and virion structural proteins, of which tentative functions were assigned to 44. Among the most interesting enzymes, due to their potential role in apoptosis and viral vesicle formation, were a caspase, a cathepsin B, several kinases, E3 ubiquitin ligases, and especially several enzymes involved in lipid metabolism, including a fatty acid elongase, a sphingomyelinase, a phosphate acyltransferase, and a patatin-like phospholipase. Comparison of SfAV-1a proteins with those of other viruses showed that 10% were orthologs of Chilo iridescent virus proteins, the highest correspondence with any virus, providing further evidence that ascoviruses evolved from a lepidopteran iridovirus. The SfAV-1a genome sequence will facilitate the determination of how ascoviruses manipulate apoptosis to generate the novel virion-containing vesicles characteristic of these viruses and enable study of their origin and evolution.
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Affiliation(s)
- Dennis K Bideshi
- Department of Entomology, University of California-Riverside, Riverside, CA 92521, USA
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