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Chen YF, Gao F, Ye XQ, Wei SJ, Shi M, Zheng HJ, Chen XX. Deep sequencing of Cotesia vestalis bracovirus reveals the complexity of a polydnavirus genome. Virology 2011; 414:42-50. [PMID: 21470650 DOI: 10.1016/j.virol.2011.03.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/26/2011] [Accepted: 03/10/2011] [Indexed: 01/05/2023]
Abstract
Here we completed the whole genome sequence of Cotesia vestalis bracovirus (CvBV) by deep sequencing and compared the genome features of CvBV to those of other polydnaviruses (PDVs). The genome is 540,215 base pairs divided into 35 genomic segments that range from 2.6 to 39.2kb. Comparison of CvBV with other PDVs shows that more segments are found, including new segments that have no corresponding segments in other phylogenetically related PDVs, which suggests that there might be still more segments not being sequenced in the present known PDVs. We identified eight gene families and five genes in CvBV, including new genes which were first found in PDVs. Strikingly, we identified a putative helicase protein displaying similarity to human Pif1 helicase, which has never been reported for other PDVs. This finding will bring new insights in research of these special viruses.
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Affiliation(s)
- Ya-Feng Chen
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310029, China
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Sequence and gene organization of 24 circles from the Cotesia plutellae bracovirus genome. Arch Virol 2009; 154:1313-27. [DOI: 10.1007/s00705-009-0441-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 06/22/2009] [Indexed: 10/20/2022]
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Desjardins CA, Gundersen-Rindal DE, Hostetler JB, Tallon LJ, Fadrosh DW, Fuester RW, Pedroni MJ, Haas BJ, Schatz MC, Jones KM, Crabtree J, Forberger H, Nene V. Comparative genomics of mutualistic viruses of Glyptapanteles parasitic wasps. Genome Biol 2008; 9:R183. [PMID: 19116010 PMCID: PMC2646287 DOI: 10.1186/gb-2008-9-12-r183] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 12/30/2008] [Indexed: 02/04/2023] Open
Abstract
Comparative genome analysis of two endosymbiotic polydnaviruses from Glyptapanteles parasitic wasps reveals new insights into the evolutionary arms race between host and parasite. Background Polydnaviruses, double-stranded DNA viruses with segmented genomes, have evolved as obligate endosymbionts of parasitoid wasps. Virus particles are replication deficient and produced by female wasps from proviral sequences integrated into the wasp genome. These particles are co-injected with eggs into caterpillar hosts, where viral gene expression facilitates parasitoid survival and, thereby, survival of proviral DNA. Here we characterize and compare the encapsidated viral genome sequences of bracoviruses in the family Polydnaviridae associated with Glyptapanteles gypsy moth parasitoids, along with near complete proviral sequences from which both viral genomes are derived. Results The encapsidated Glyptapanteles indiensis and Glyptapanteles flavicoxis bracoviral genomes, each composed of 29 different size segments, total approximately 517 and 594 kbp, respectively. They are generated from a minimum of seven distinct loci in the wasp genome. Annotation of these sequences revealed numerous novel features for polydnaviruses, including insect-like sugar transporter genes and transposable elements. Evolutionary analyses suggest that positive selection is widespread among bracoviral genes. Conclusions The structure and organization of G. indiensis and G. flavicoxis bracovirus proviral segments as multiple loci containing one to many viral segments, flanked and separated by wasp gene-encoding DNA, is confirmed. Rapid evolution of bracovirus genes supports the hypothesis of bracovirus genes in an 'arms race' between bracovirus and caterpillar. Phylogenetic analyses of the bracoviral genes encoding sugar transporters provides the first robust evidence of a wasp origin for some polydnavirus genes. We hypothesize transposable elements, such as those described here, could facilitate transfer of genes between proviral segments and host DNA.
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Chen YF, Shi M, Liu PC, Huang F, Chen XX. Characterization of an IkappaB-like gene in Cotesia vestalis polydnavirus. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2008; 68:71-78. [PMID: 18454492 DOI: 10.1002/arch.20253] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Cotesia vestalis (Braconidae, Hymenoptera) depends mainly on 3 regulatory factors to manipulate its host's development and immune response, including polydnavirus, venom, and teratocytes, among which polydnavirus plays a key role in suppressing the host immune system. In the present work, we cloned the full sequence of gene CvBV-ank2, encoding an IkappaB-like protein in C. vestalis polydnavirus (CvBV). The full sequence of CvBV-ank2 is 955 bp, encoding 162 amino acids with a calculated molecular mass of 18,355 Da. CvBV-ank2 shares high similarity with the exon I and exon II of CvBV-ank1, which is on the same segment with CvBV-ank2. This result suggests that gene duplication might occur in CvBV-ank1 and CvBV-ank2. Phylogenetic analysis indicated that CvBV-ank2 and CvBV-ank1, both on segment CvBV-S2, are, respectively, closely related with CcBV-26.3 and CcBV-26.2, both on segment Circle26 of C. congregata polydnavirus (CcBV). BLAST search using the sequence of segment CvBV-S2 as a query revealed that segment CvBV-S2 shares 90% max identity with segment Circle26 of CcBV over 67% query coverage. These results demonstrate that there is not only gene similarity, but also segment similarity between CvBV and CcBV. Transcripts of CvBV-ank2 were detected as early as 0.5 h post-parasitization and continued to be detected for 6 days, indicating that CvBV-ank2 might be involved in the early protection of the parasitoid egg.
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Affiliation(s)
- Ya-Feng Chen
- Institute of Insect Sciences, Zhejiang University, Hangzhou, China
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Shi M, Chen YF, Huang F, Liu PC, Zhou XP, Chen XX. Characterization of a novel gene encoding ankyrin repeat domain from Cotesia vestalis polydnavirus (CvBV). Virology 2008; 375:374-82. [DOI: 10.1016/j.virol.2008.02.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 02/04/2008] [Accepted: 02/21/2008] [Indexed: 10/22/2022]
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Chen YF, Shi M, Huang F, Chen XX. Characterization of two genes of Cotesia vestalis polydnavirus and their expression patterns in the host Plutella xylostella. J Gen Virol 2007; 88:3317-3322. [DOI: 10.1099/vir.0.82999-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cotesia vestalis is an endoparasitoid of larval stages of Plutella xylostella, the diamondback moth. For successful parasitization, this parasitoid injects a polydnavirus into its host during oviposition. Here we isolated two genes, which we named CvBV1 and CvBV2. CvBV1 was located on segment CvBV-S5 with a size of 790 bp, while CvBV2 was located on segment CvBV-S51 with a size of 459 bp. A gene copy of CvBV2 was found on segment CvBV-S48, which we name CvBV2’. Gene duplication occurred in both genes, tandem gene duplication for CvBV1 and segmental duplication for CvBV2. Gene transcripts of the two genes were detected in hosts as early as 0.5 h post-parasitization (p.p.) and continued to be detected for six days, and tissue-specific expression patterns showed that they could be detected in the haemolymph and brain at 2 h p.p., suggesting that they could participate in early protection of parasitoid eggs from host cellular encapsulation.
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Affiliation(s)
- Ya-Feng Chen
- Institute of Insect Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, PR China
| | - Min Shi
- Institute of Insect Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, PR China
| | - Fang Huang
- Institute of Insect Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, PR China
| | - Xue-xin Chen
- Institute of Insect Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, PR China
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Desjardins CA, Gundersen-Rindal DE, Hostetler JB, Tallon LJ, Fuester RW, Schatz MC, Pedroni MJ, Fadrosh DW, Haas BJ, Toms BS, Chen D, Nene V. Structure and evolution of a proviral locus of Glyptapanteles indiensis bracovirus. BMC Microbiol 2007; 7:61. [PMID: 17594494 PMCID: PMC1919376 DOI: 10.1186/1471-2180-7-61] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 06/26/2007] [Indexed: 11/18/2022] Open
Abstract
Background Bracoviruses (BVs), a group of double-stranded DNA viruses with segmented genomes, are mutualistic endosymbionts of parasitoid wasps. Virus particles are replication deficient and are produced only by female wasps from proviral sequences integrated into the wasp genome. Virus particles are injected along with eggs into caterpillar hosts, where viral gene expression facilitates parasitoid survival and therefore perpetuation of proviral DNA. Here we describe a 223 kbp region of Glyptapanteles indiensis genomic DNA which contains a part of the G. indiensis bracovirus (GiBV) proviral genome. Results Eighteen of ~24 GiBV viral segment sequences are encoded by 7 non-overlapping sets of BAC clones, revealing that some proviral segment sequences are separated by long stretches of intervening DNA. Two overlapping BACs, which contain a locus of 8 tandemly arrayed proviral segments flanked on either side by ~35 kbp of non-packaged DNA, were sequenced and annotated. Structural and compositional analyses of this cluster revealed it exhibits a G+C and nucleotide composition distinct from the flanking DNA. By analyzing sequence polymorphisms in the 8 GiBV viral segment sequences, we found evidence for widespread selection acting on both protein-coding and non-coding DNA. Comparative analysis of viral and proviral segment sequences revealed a sequence motif involved in the excision of proviral genome segments which is highly conserved in two other bracoviruses. Conclusion Contrary to current concepts of bracovirus proviral genome organization our results demonstrate that some but not all GiBV proviral segment sequences exist in a tandem array. Unexpectedly, non-coding DNA in the 8 proviral genome segments which typically occupies ~70% of BV viral genomes is under selection pressure suggesting it serves some function(s). We hypothesize that selection acting on GiBV proviral sequences maintains the genetic island-like nature of the cluster of proviral genome segments described herein. In contrast to large differences in the predicted gene composition of BV genomes, sequences that appear to mediate processes of viral segment formation, such as proviral segment excision and circularization, appear to be highly conserved, supporting the hypothesis of a single origin for BVs.
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Affiliation(s)
- Christopher A Desjardins
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
- Department of Biology, University of Rochester, Rochester, New York, USA
| | | | - Jessica B Hostetler
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
| | - Luke J Tallon
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
| | - Roger W Fuester
- USDA-ARS Beneficial Insect Introductions Research Laboratory, Newark, Delaware, USA
| | - Michael C Schatz
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, USA
| | - Monica J Pedroni
- USDA-ARS Insect Biocontrol Laboratory, Beltsville, Maryland, USA
| | - Douglas W Fadrosh
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
| | - Brian J Haas
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
| | - Bradley S Toms
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
| | - Dan Chen
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
| | - Vishvanath Nene
- The Institute for Genomic Research, a division of J. Craig Venter Institute, Rockville, Maryland, USA
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Gundersen-Rindal DE, Pedroni MJ. Characterization and transcriptional analysis of protein tyrosine phosphatase genes and an ankyrin repeat gene of the parasitoid Glyptapanteles indiensis polydnavirus in the parasitized host. J Gen Virol 2006; 87:311-322. [PMID: 16432017 DOI: 10.1099/vir.0.81326-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glyptapanteles indiensis (Braconidae, Hymenoptera) is an endoparasitoid of Lymantria dispar, the gypsy moth. Expression of G. indiensis polydnavirus (GiBV)-encoded genes within the pest host results in inhibition of immune response and development and alteration of physiology, enabling successful development of the parasitoid. Here, GiBV genome segment F (segF), an 18·6 kb segment shown to encode nine protein tyrosine phosphatase (PTP) genes and a single ankyrin repeat gene (ank), is analysed. PTPs have presumed function as regulators of signal transduction, while ankyrin repeat genes are hypothesized to function in inhibition of NF-κB signalling in the parasitized host. In this study, transcription of each gene was mapped by 5′- and 3′-RACE (rapid amplification of cDNA ends) and temporal and tissue-specific expression was examined in the parasitized host. For polydnavirus gene prediction in the parasitized host, no available gene prediction parameters were entirely precise. The mRNAs for each GiBV segF gene initiated between 30 and 112 bp upstream of the translation initiation codon. All were encoded in single open reading frames (ORFs), with the exception of PTP9, which was transcribed as a bicistronic message with the adjacent ank gene. RT-PCR indicated that all GiBV segF PTPs were expressed early in parasitization and, for most, expression was sustained over the course of at least 7 days after parasitization, suggesting importance in both early and sustained virus-induced immunosuppression and alteration of physiology. Tissue-specific patterns of PTP expression of GiBV segF genes were variable, suggesting differing roles in facilitating parasitism.
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Affiliation(s)
- D E Gundersen-Rindal
- US Department of Agriculture, Agricultural Research Service, Insect Biocontrol Laboratory, Bldg 011A, Room 214, BARC West, Beltsville, MD 20705, USA
| | - M J Pedroni
- US Department of Agriculture, Agricultural Research Service, Insect Biocontrol Laboratory, Bldg 011A, Room 214, BARC West, Beltsville, MD 20705, USA
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Choi JY, Roh JY, Kang JN, Shim HJ, Woo SD, Jin BR, Li MS, Je YH. Genomic segments cloning and analysis of Cotesia plutellae polydnavirus using plasmid capture system. Biochem Biophys Res Commun 2005; 332:487-93. [PMID: 15896714 DOI: 10.1016/j.bbrc.2005.04.146] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Accepted: 04/28/2005] [Indexed: 10/25/2022]
Abstract
Cotesia plutellae polydnaviruses (CpBV) has a segmented genome consisting of multiple circular double stranded DNAs. Recently, we have developed an easy, simple, and convenient system based on Tn7 transposition in order to clone genomic segments of CpBV in Escherichia coli cell and designated plasmid capture system (PCS). The PCS donor-S transferred a pUC19 origin of replication and an ampicillin resistance marker into CpBV genomic DNA by in vitro transposition. Through PCS system, we were able to clone 53 genomic clones ranging from 0.1 to 25.5 kb and further they were classified into 29 segments by their sizes and restriction endonuclease patterns. Among them, a complete nucleotide sequence of CpBV-S28 segment was determined and 10 putative genes were predicted from this segment. Interestingly, 9 of 10 putative ORFs had high level of similarities with catalytic domain of protein tyrosine phosphatase. Also, ORF2807 showed similarity with EP1-like proteins of C. congregata polydnavirus.
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Affiliation(s)
- Jae Young Choi
- School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Republic of Korea
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10
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Bonvin M, Marti D, Wyder S, Kojic D, Annaheim M, Lanzrein B. Cloning, characterization and analysis by RNA interference of various genes of the Chelonus inanitus polydnavirus. J Gen Virol 2005; 86:973-983. [PMID: 15784890 DOI: 10.1099/vir.0.80833-0] [Citation(s) in RCA: 14] [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
Successful parasitism of some endoparasitic wasps depends on an obligately symbiotic association with polydnaviruses. These unique viruses have a segmented genome consisting of circles of double-stranded (ds) DNA and do not replicate in the parasitized host. They are produced in the wasp's ovary and injected into the host along with the egg. Chelonus inanitus is an egg–larval parasitoid; its polydnavirus (CiV) has been shown to protect the parasitoid larva from the host's immune system and to induce developmental arrest in the prepupal stage. The genome of CiV consists of at least 10–12 segments and five have been sequenced up to now. Here, the complete (CiV12g2) or partial (CiV12g1, CiV16.8g1) cloning of three new CiV genes is reported. All three occur only on one viral segment and have no similarity to other known polydnavirus genes, with the exception of a high similarity of CiV12g1 to CiV14g1 and CiV12g2 to CiV14g2. Furthermore, the first attempt of in vivo application of RNA interference to study the function of polydnavirus genes is shown. Injection of dsRNA of two late- and one early- and late-expressed CiV genes into CiV/venom-containing host eggs partially rescued last-instar larvae from developmental arrest. Injection of the same dsRNAs into parasitized eggs partially reduced parasitoid survival, mainly by preventing the successful emergence of the parasitoid from the host. These viral genes thus seem to be involved in inducing developmental arrest and in keeping the cuticle soft, which appears to be necessary for parasitoid emergence and host feeding.
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Affiliation(s)
- Marianne Bonvin
- Institute of Cell Biology, University of Berne, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Dorothee Marti
- Institute of Cell Biology, University of Berne, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Stefan Wyder
- Institute of Cell Biology, University of Berne, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Dejan Kojic
- Institute of Cell Biology, University of Berne, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Marc Annaheim
- Institute of Cell Biology, University of Berne, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Beatrice Lanzrein
- Institute of Cell Biology, University of Berne, Baltzerstrasse 4, CH-3012 Bern, Switzerland
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Chen YP, Gundersen-Rindal DE, Lynn DE. BACULOVIRUS-BASED EXPRESSION OF AN INSECT VIRAL PROTEIN IN 12 DIFFERENT INSECT CELL LINES. ACTA ACUST UNITED AC 2005; 41:43-9. [PMID: 15926859 DOI: 10.1290/0412081.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ability of 12 unique lepidopteran insect cell lines from Anticarsia gemmatalis, Heliothis virescens, Lymantria dispar (two lines), Mamestra brassica, Plutella xylostella, Spodoptera frugiperda (two lines), and Trichoplusia ni (three lines) to support production of a recombinant polydnavirus (PDV) protein (GiPDV 1.1) expressed using the Bac-to-Bac baculovirus expression system was examined. Polydnavirus gene GiPDV 1.1 was cloned into the pFastBac baculovirus vector under the control of the polyhedron promoter, followed by generation of recombinant bacmid-GiPDV 1.1 by site-specific transposition. The ability of each insect cell line to support recombinant PDV gene expression was estimated using reverse transcriptase-polymerase chain reaction and Western blot. Each insect cell line infected with recombinant bacmid-GiPDV 1.1 and tested in this study was capable of supporting and producing recombinant protein. Time course expression analysis showed that 72-96 h after transfection to be the optimal time for harvest of recombinant protein for each insect cell line.
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Affiliation(s)
- Y P Chen
- Bee Research Laboratory, USDA-ARS, Beltsville, Maryland 20705, USA.
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12
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Kroemer JA, Webb BA. Polydnavirus genes and genomes: emerging gene families and new insights into polydnavirus replication. ANNUAL REVIEW OF ENTOMOLOGY 2004; 49:431-456. [PMID: 14651471 DOI: 10.1146/annurev.ento.49.072103.120132] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Polydnavirus genome sequencing is providing new insights into viral genome organization and viral gene function. Sequence analyses demonstrate that the genomes of these viral mutualists are largely noncoding but maintain genes and gene families that are unrelated to other viral genes. Interestingly, these organizational patterns in polydnavirus genomes are evident in both the bracovirus and ichnovirus genera, even though these two genera are evolutionarily unrelated. The identity and function of some polydnavirus gene families are considered with some functions experimentally supported and others implied by homology relationships with known insect genes. The evidence relative to polydnavirus origins and evolution is considered but remains an area of speculation. However, sequencing of these viral genomes has been informative and provides opportunities for productive investigation of these unusual mutualistic insect viruses.
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Affiliation(s)
- Jeremy A Kroemer
- Department of Entomology, University of Kentucky, S-225 Agricultural Sciences Center North, Lexington, Kentucky 40546, USA.
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Chen YP, Higgins JA, Gundersen-Rindal DE. Quantitation of a Glyptapanteles indiensis polydnavirus gene expressed in parasitized host, Lymantria dispar, by real-time quantitative RT-PCR. J Virol Methods 2003; 114:125-33. [PMID: 14625047 DOI: 10.1016/j.jviromet.2003.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Glyptapanteles indiensis is a polydnavirus-carrying wasp that parasitizes early instar gypsy moth larvae. During oviposition, the wasp injects calyx fluid containing polydnavirus along with its eggs into the host. Within the host, expression of polydnavirus genes triggers a set of changes in host physiology, which are of critical importance for the survival of the wasp. In the present study, a G. indiensis polydnavirus (GiPDV) gene, represented by cDNA clone GiPDV 1.1, was selected for expression analysis in the parasitized host. The GiPDV 1.1 gene transcript was detected in host hemolymph 30 min post-parasitization (pp) and continued to be detected for six days. The level of GiPDV 1.1 expression varied in different host tissues and expression in the brain was lower than in the hemolymph. The findings suggest that GiPDV 1.1 could be involved in early protection of parasitoid eggs from host cellular encapsulation. The temporal and spatial variations in PDV gene expression in different host tissues post-parasitization affirm their specific host regulation mechanism.
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Affiliation(s)
- Y P Chen
- US Department of Agriculture (USDA)--Agricultural Research Service (ARS), Insect Biocontrol Laboratory, Room 214, Building 011A BARC West, Beltsville, MD 20705, USA
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Gundersen-Rindal DE, Lynn DE. Polydnavirus integration in lepidopteran host cells in vitro. JOURNAL OF INSECT PHYSIOLOGY 2003; 49:453-462. [PMID: 12770624 DOI: 10.1016/s0022-1910(03)00062-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The long-term persistence of polydnavirus (PDV) DNA in infected lepidopteran cell cultures has suggested that at least some of the virus sequences become integrated permanently into the cell genome. In the current study, we provide supportive evidence of this event. Cloned libraries were prepared from two different Lymantria dispar (gypsy moth) cell lines that had been maintained in continuous culture for more than five years after infection with Glyptapanteles indiensis PDV (GiPDV). Junction clones containing both insect chromosomal and polydnaviral sequences were isolated. Precise integration junction sites were identified by sequence comparison of linear (integrated) and circular forms of the GiPDV genome segment F, from which viral sequences originated. Host chromosomal sequences at the site of integration varied between the two L. dispar cell lines but virus sequence junctions were identical and contained a 4-base pair CATG palindromic repeat. The GiPDV segment F does not encode any self-replication or self-insertion proteins, suggesting a host-derived mechanism is responsible for its in vitro integration. The chromosomal site of one junction clone contained sequences indicative of a new L. dispar retrotransposon, including a putative reverse transcriptase and integrase located upstream of the site of viral integration. A potential mechanism is proposed for the integration of PDV DNA in vitro. It remains to be seen if integration of the virus also occurs in the lepidopteran host in vivo.
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Affiliation(s)
- D E Gundersen-Rindal
- US Department of Agriculture, Agricultural Research Service, Insect Biocontrol Laboratory, Beltsville, MD 20705, USA.
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