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Lorenzi A, Arvin MJ, Burke GR, Strand MR. Functional characterization of Microplitis demolitor bracovirus genes that encode nucleocapsid components. J Virol 2023; 97:e0081723. [PMID: 37877717 PMCID: PMC10688341 DOI: 10.1128/jvi.00817-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/19/2023] [Indexed: 10/26/2023] Open
Abstract
IMPORTANCE Understanding how bracoviruses (BVs) function in wasps is of broad interest in the study of virus evolution. This study characterizes most of the Microplitis demolitor bracovirus (MdBV) genes whose products are nucleocapsid components. Results indicate several genes unknown outside of nudiviruses and BVs are essential for normal capsid assembly. Results also indicate most MdBV tyrosine recombinase family members and the DNA binding protein p6.9-1 are required for DNA processing and packaging into nucleocapsids.
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Affiliation(s)
- Ange Lorenzi
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Michael J. Arvin
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Gaelen R. Burke
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Michael R. Strand
- Department of Entomology, University of Georgia, Athens, Georgia, USA
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2
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Zhang P, Liu ZY, Yu D, Xu CX, Hu Y, Liang YP, Jin J, Li M. Microplitis bicoloratus parasitism promotes cyclophilin D-p53 interaction to induce apoptosis of hemocytes in Spodoptera litura. Arch Insect Biochem Physiol 2023; 112:e21970. [PMID: 36200410 DOI: 10.1002/arch.21970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/04/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
Microplitis bicoloratus parasitism can induce apoptosis of hemocytes in the M. bicolortus host, Spodoptera litura. However, it is unclear how M. bicolortus parasitism regulates host signaling pathways to induce apoptosis. Expression of cyclophilin D (CypD) and p53 was significantly upregulated in S. litura hemocytes at 6 days postparasitization. In the parasitized hemocytes, there was mitochondrial membrane potential (△Ψm ) loss, cytochrome c (Cyt C) release from mitochondria, and caspase-3 activation. These occurred while hemocytes were undergoing upregulation of CypD and p53. Parasitism also promoted the interaction between CypD and p53. CypD silencing could rescue the apoptotic phenotypes induced by parasitism, but had no effect on apoptosis in unparasitized S. litura. These findings suggest that the CypD-p53 pathway may be an important component of the parasitism-induced immunosuppressive response and establish a basis for further studies of parasitoid/host interactions.
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Affiliation(s)
- Pan Zhang
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulation, School of Life Sciences, Yunnan University, Kunming, China
| | - Zi-Yan Liu
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulation, School of Life Sciences, Yunnan University, Kunming, China
- Center of Molecular Biology of Tropical Crops, Yunnan Institute of Tropical Crops, Jinghong, China
| | - Dan Yu
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulation, School of Life Sciences, Yunnan University, Kunming, China
| | - Cui-Xian Xu
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulation, School of Life Sciences, Yunnan University, Kunming, China
- School of Health, Yunnan Technology and Business University, Kunming, China
| | - Yan Hu
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulation, School of Life Sciences, Yunnan University, Kunming, China
| | - Ya-Ping Liang
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulation, School of Life Sciences, Yunnan University, Kunming, China
| | - Jie Jin
- School of Urban and Environmental Sciences, Yunnan University of Finance and Economics, Kunming, China
| | - Ming Li
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulation, School of Life Sciences, Yunnan University, Kunming, China
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3
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Gao HS, Hu RM, Wang ZH, Ye XQ, Wu XT, Huang JH, Wang ZZ, Chen XX. A Polydnavirus Protein Tyrosine Phosphatase Negatively Regulates the Host Phenoloxidase Pathway. Viruses 2022; 15:56. [PMID: 36680096 PMCID: PMC9866809 DOI: 10.3390/v15010056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 12/29/2022] Open
Abstract
Polydnavirus (PDV) is a parasitic factor of endoparasitic wasps and contributes greatly to overcoming the immune response of parasitized hosts. Protein tyrosine phosphatases (PTPs) regulate a wide variety of biological processes at the post-transcriptional level in mammals, but knowledge of PDV PTP action during a parasitoid−host interaction is limited. In this study, we characterized a PTP gene, CvBV_12-6, derived from Cotesia vestalis bracovirus (CvBV), and explored its possible regulatory role in the immune response of the host Plutella xylostella. Our results from qPCR show that CvBV_12-6 was highly expressed in hemocytes at an early stage of parasitization. To explore CvBV_12-6 function, we specifically expressed CvBV_12-6 in Drosophila melanogaster hemocytes. The results show that Hml-Gal4 > CvBV_12-6 suppressed the phenoloxidase activity of hemolymph in D. melanogaster, but exerted no effect on the total count or the viability of the hemocytes. In addition, the Hml-Gal4 > CvBV_12-6 flies exhibited decreased antibacterial abilities against Staphylococcus aureus. Similarly, we found that CvBV_12-6 significantly suppressed the melanization of the host P. xylostella 24 h post parasitization and reduced the viability, but not the number, of hemocytes. In conclusion, CvBV_12-6 negatively regulated both cellular and humoral immunity in P. xylostella, and the related molecular mechanism may be universal to insects.
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Affiliation(s)
- Hong-Shuai Gao
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
| | - Rong-Min Hu
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
| | - Ze-Hua Wang
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
| | - Xi-Qian Ye
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
| | - Xiao-Tong Wu
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
| | - Jian-Hua Huang
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
| | - Zhi-Zhi Wang
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
- The Rural Development Academy, Zhejiang University, Hangzhou 310058, China
| | - Xue-Xin Chen
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China
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Sawa T, Tanaka T, Kato Y, Nakamatsu Y. Cky811 protein expressed by polydnavirus and venom gland of Cotesia kariyai regulates the host Mythimna separata larvae immune response function of C-type lectin responsible for foreign substance recognition which suppresses its melanization and encapsulation. Arch Insect Biochem Physiol 2021; 107:e21786. [PMID: 33818830 DOI: 10.1002/arch.21786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 05/21/2023]
Abstract
Cotesia kariyai (Ck) larvae implanted into the body cavity of the Mythimna separata (armyworm) larvae get melanized and encapsulated after adhesion by hemocytes called hyperspread cells (HSCs). The present study showed that HSCs could not adhere to the implanted Ck larvae in armyworm larvae after injection of Ck polydnavirus (CkPDV) + venom (V), thus melanization and encapsulation could not occur. A C-type lectin called Mys-IML of the host armyworm larvae was considered to be involved in the recognition of foreign substances which always expressed in hemocytes. The CkPDV DNA encodes a C-type lectin called Cky811 that has high amino acid homology to Mys-IML. HSCs did not adhere when CkPDV + V was mixed with the hemolymph of armyworm larvae on glass slides and incubated in vitro, but the addition of anti-Cky811 antibody enabled HSCs to adhere. The messenger RNA (mRNA) expression of Mys-IML in armyworm larvae injected with CkPDV + V became undetectable by 6 h. On the contrary, Cky811 mRNA was well expressed in the hemocytes of armyworm larvae injected with CkPDV + V from 0.5 to 6 h. Cky811 protein was also detected in the crude extracts from Ck venom gland + Ck venom reservoir, suggesting that these proteins regulate foreign substance recognition by the armyworm within 0.5 h. These results suggest that CkPDV + V suppresses mRNA expression of Mys-IML, and that Cky811 protein expressed in hemocytes regulates foreign substance recognition of Mys-IML, resulting in inhibition of the downstream reaction steps: HSCs adhesion, melanization, and encapsulation.
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Affiliation(s)
- Tomomi Sawa
- Faculty of Education, Kogakkan University, Ise City, Mie Prefecture, Japan
| | - Toshiharu Tanaka
- International Center for Research and Education in Agriculture, Nagoya University, Nagoya City, Aichi Prefecture, Japan
| | - Yoshiaki Kato
- BASF Japan, AgSolution farm, Sanmu City, Chiba Prefecture, Japan
| | - Yutaka Nakamatsu
- Faculty of Education, Kogakkan University, Ise City, Mie Prefecture, Japan
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Cai QC, Chen CX, Liu HY, Zhang W, Han YF, Zhang Q, Zhou GF, Xu S, Liu T, Xiao W, Zhu QS, Luo KJ. Interactions of Vank proteins from Microplitis bicoloratus bracovirus with host Dip3 suppress eIF4E expression. Dev Comp Immunol 2021; 118:103994. [PMID: 33417999 DOI: 10.1016/j.dci.2021.103994] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/31/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
Microplitis bicoloratus bracovirus (MbBV) inhibits the immune response of the host Spodoptera litura by disrupting nuclear factor (NF)-κB signaling and downstream gene expression. However, the underlying molecular mechanisms are not well understood. Herein, we report that viral ankyrin (Vank) proteins interacted with host dorsal-interacting protein 3 (Dip3) to selectively inhibit the transcription of eukaryotic translation initiation factor 4 E (eIF4E). Dip3 and Vank proteins were co-expressed and colocalized in the nucleus. Furthermore, ectopic expression of Dip3 rescued the transcription of some NF-κB-dependent genes suppressed by Vank proteins, including eIF4E. Co-immunoprecipitation and pull-down assays confirmed that Vank proteins interacted with and bound to full-length Dip3, which including MADF, DNA-binding protein, BESS, and protein-protein interaction motifs as well as non-motif sequences. In vivo, RNAi-mediated dip3 silencing decreased eIF4E levels and was accompanied by an immunosuppressive phenotype in S. litura. Our results provided novel insights into the regulation of host transcription during immune suppression by viral proteins that modulate nuclear NF-κB signaling.
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Affiliation(s)
- Qiu-Chen Cai
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China
| | - Chang-Xu Chen
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China
| | - Hong-Yu Liu
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China
| | - Wei Zhang
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China
| | - Yun-Feng Han
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China
| | - Qi Zhang
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China
| | - Gui-Fang Zhou
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China
| | - Sha Xu
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China
| | - Tian Liu
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China
| | - Wei Xiao
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China
| | - Qi-Shun Zhu
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China
| | - Kai-Jun Luo
- School of Life Sciences, Yunnan University, Kunming, 650500, PR China; Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, 650500, PR China; Biocontrol Engineering Research Centre of Crop Disease & Pest in Yunnan Province, Kunming, 650500, PR China.
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Tang CK, Tsai CH, Wu CP, Lin YH, Wei SC, Lu YH, Li CH, Wu YL. MicroRNAs from Snellenius manilae bracovirus regulate innate and cellular immune responses of its host Spodoptera litura. Commun Biol 2021; 4:52. [PMID: 33420334 PMCID: PMC7794284 DOI: 10.1038/s42003-020-01563-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 10/18/2020] [Indexed: 01/29/2023] Open
Abstract
To avoid inducing immune and physiological responses in insect hosts, parasitoid wasps have developed several mechanisms to inhibit them during parasitism, including the production of venom, specialized wasp cells, and symbioses with polydnaviruses (PDVs). These mechanisms alter the host physiology to give the wasp offspring a greater chance of survival. However, the molecular mechanisms for most of these alterations remain unclear. In the present study, we applied next-generation sequencing analysis and identified several miRNAs that were encoded in the genome of Snellenius manilae bracovirus (SmBV), and expressed in the host larvae, Spodoptera litura, during parasitism. Among these miRNAs, SmBV-miR-199b-5p and SmBV-miR-2989 were found to target domeless and toll-7 in the host, which are involved in the host innate immune responses. Microinjecting the inhibitors of these two miRNAs into parasitized S. litura larvae not only severely decreased the pupation rate of Snellenius manilae, but also restored the phagocytosis and encapsulation activity of the hemocytes. The results demonstrate that these two SmBV-encoded miRNAs play an important role in suppressing the immune responses of parasitized hosts. Overall, our study uncovers the functions of two SmBV-encoded miRNAs in regulating the host innate immune responses upon wasp parasitism.
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Affiliation(s)
- Cheng-Kang Tang
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Chih-Hsuan Tsai
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Carol-P Wu
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yu-Hsien Lin
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Sung-Chan Wei
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yun-Heng Lu
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Cheng-Hsun Li
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yueh-Lung Wu
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan.
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Ignesti M, Ferrara R, Romani P, Valzania L, Serafini G, Pennacchio F, Cavaliere V, Gargiulo G. A polydnavirus-encoded ANK protein has a negative impact on steroidogenesis and development. Insect Biochem Mol Biol 2018; 95:26-32. [PMID: 29559251 DOI: 10.1016/j.ibmb.2018.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/12/2018] [Accepted: 03/16/2018] [Indexed: 06/08/2023]
Abstract
Polydnaviruses (PDV) are viral symbionts associated with ichneumonid and braconid wasps parasitizing moth larvae, which are able to disrupt the host immune response and development, as well as a number of other physiological pathways. The immunosuppressive role of PDV has been more intensely investigated, while very little is known about the PDV-encoded factors disrupting host development. Here we address this research issue by further expanding the functional analysis of ankyrin genes encoded by the bracovirus associated with Toxoneuron nigriceps (Hymenoptera, Braconidae). In a previous study, using Drosophila melanogaster as experimental model system, we demonstrated the negative impact of TnBVank1 impairing the ecdysone biosynthesis by altering endocytic traffic in prothoracic gland cells. With a similar approach here we demonstrate that another member of the viral ank gene family, TnBVank3, does also contribute to the disruption of ecdysone biosynthesis, but with a completely different mechanism. We show that its expression in Drosophila prothoracic gland (PG) blocks the larval-pupal transition by impairing the expression of steroidogenic genes. Furthermore, we found that TnBVank3 affects the expression of genes involved in the insulin/TOR signaling and the constitutive activation of the insulin pathway in the PG rescues the pupariation impairment. Collectively, our data demonstrate that TnBVANK3 acts as a virulence factor by exerting a synergistic and non-overlapping function with TnBVANK1 to disrupt the ecdysone biosynthesis.
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Affiliation(s)
- Marilena Ignesti
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via Selmi 3 Bologna, Italy
| | - Rosalba Ferrara
- Dipartimento di Agraria - Laboratorio di Entomologia "E. Tremblay", Università di Napoli 'Federico II', Portici (NA), Italy
| | - Patrizia Romani
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via Selmi 3 Bologna, Italy; Dipartimento di Medicina Molecolare, Università di Padova, Padova, Italy
| | - Luca Valzania
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via Selmi 3 Bologna, Italy; Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Giulia Serafini
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via Selmi 3 Bologna, Italy
| | - Francesco Pennacchio
- Dipartimento di Agraria - Laboratorio di Entomologia "E. Tremblay", Università di Napoli 'Federico II', Portici (NA), Italy.
| | - Valeria Cavaliere
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via Selmi 3 Bologna, Italy.
| | - Giuseppe Gargiulo
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via Selmi 3 Bologna, Italy.
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Seehausen ML, Cusson M, Régnière J, Bory M, Stewart D, Djoumad A, Smith SM, Martel V. High temperature induces downregulation of polydnavirus gene transcription in lepidopteran host and enhances accumulation of host immunity gene transcripts. J Insect Physiol 2017; 98:126-133. [PMID: 28041943 DOI: 10.1016/j.jinsphys.2016.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 12/23/2016] [Indexed: 06/06/2023]
Abstract
Endoparasitoids face the challenge of overcoming the immune reaction of their hosts, which typically consists of encapsulation and melanisation of parasitoid eggs or larvae. Some endoparasitic wasps such as the solitary Tranosema rostrale (Hymenoptera: Ichneumonidae) that lay their eggs in larvae of the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae), have evolved a symbiotic relationship with a polydnavirus (PDV), which in turn helps them suppress the host's immune response. We observed an increase in mortality of immature T. rostrale with increasing temperature, and we tested two hypotheses about the mechanisms involved: high temperatures (1) hamper the expression of T. rostrale PDV genes and (2) enhance the expression of spruce budworm immunity-related genes. Dissections of parasitized spruce budworm larvae reared at 30°C revealed that most parasitoid eggs or larvae had died as a result of encapsulation and melanisation by the host. A qPCR analysis of T. rostrale PDV (TrIV) gene expression showed that the transcription of several TrIV genes in host larvae was downregulated at high temperature. On the other hand, encapsulation, but not melanisation, of foreign bodies in spruce budworm larvae was enhanced at high temperatures, as shown by the injection of Sephadex™ beads into larvae. However, at the molecular level, the transcription of genes related to spruce budworm's melanisation process (prophenoloxidase 1 and 2) was upregulated. Our results support the hypothesis that a temperature-dependent increase of encapsulation response is due to the combined effects of reduced expression of TrIV genes and enhanced expression of host immune genes.
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Affiliation(s)
- M Lukas Seehausen
- University of Toronto, Faculty of Forestry, 33 Willcocks Street, Toronto, Ontario M5S 3B3, Canada.
| | - Michel Cusson
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., Québec G1V 4C7, Canada
| | - Jacques Régnière
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., Québec G1V 4C7, Canada
| | - Maxence Bory
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., Québec G1V 4C7, Canada
| | - Don Stewart
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., Québec G1V 4C7, Canada
| | - Abdelmadjid Djoumad
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., Québec G1V 4C7, Canada
| | - Sandy M Smith
- University of Toronto, Faculty of Forestry, 33 Willcocks Street, Toronto, Ontario M5S 3B3, Canada
| | - Véronique Martel
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., Québec G1V 4C7, Canada
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Kim E, Kim Y, Yeam I, Kim Y. Transgenic Expression of a Viral Cystatin Gene CpBV-CST1 in Tobacco Confers Insect Resistance. Environ Entomol 2016; 45:1322-1331. [PMID: 27550161 DOI: 10.1093/ee/nvw105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
A viral gene, CpBV-CST1, was identified from a polydnavirus Cotesia plutellae bracovirus (CpBV). Its protein product was significantly toxic to lepidopteran insects. This study generated a transgenic tobacco plant expressing CpBV-CST1 Expression of transgene CpBV-CST1 was confirmed in T1 generation (second generation after transgenesis) in both mRNA and protein levels. Young larvae of Spodoptera exigua (Hübner) suffered high mortalities after feeding on transgenic tobacco. All 10 T1 transgenic tobacco plants had no significant variation in speed-to-kill. In order to further explore insect resistance of these transgenic tobaccos, bioassays were performed by assessing antixenosis and antibiosis. S. exigua larvae significantly avoided T1 plants in a choice test. Larvae fed with T1 plant exhibited significant decrease in protease activity in the midgut due to consuming CpBV-CST1 protein produced by the transgenic plant. Furthermore, the transgenic tobacco exhibited similar insect resistance to other tobacco-infesting insects, including a leaf-feeding insect, Helicoverpa assulta, and a sap-feeding insect, Myzus persicae These results demonstrate that a viral cystatin gene can be used to develop insect-resistant transgenic plant, suggesting a prospective possibility of expanding the current transgenic approach to high-valued crops.
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Affiliation(s)
- E Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, Korea (; ; )
| | - Y Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, Korea (; ; )
| | - I Yeam
- Department of Horticulture and Breeding, Andong National University, Andong 36729, Korea
| | - Y Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, Korea (; ; )
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Valzania L, Romani P, Tian L, Li S, Cavaliere V, Pennacchio F, Gargiulo G. A polydnavirus ANK protein acts as virulence factor by disrupting the function of prothoracic gland steroidogenic cells. PLoS One 2014; 9:e95104. [PMID: 24743267 PMCID: PMC3990622 DOI: 10.1371/journal.pone.0095104] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/21/2014] [Indexed: 12/24/2022] Open
Abstract
Polydnaviruses are obligate symbionts integrated as proviruses in the genome of some ichneumonoid wasps that parasitize lepidopteran larvae. Polydnavirus free viral particles, which are injected into the host at oviposition, express virulence factors that impair immunity and development. To date, most studies have focused on the molecular mechanisms underpinning immunosuppression, whereas how viral genes disrupt the endocrine balance remains largely uninvestigated. Using Drosophila as a model system, the present report analyzes the function of a member of the ankyrin gene family of the bracovirus associated with Toxoneuron nigriceps, a larval parasitoid of the noctuid moth Heliothis virescens. We found that the TnBVank1 expression in the Drosophila prothoracic gland blocks the larval-pupal molt. This phenotype can be rescued by feeding the larvae with 20-hydroxyecdysone. The localization of the TnBVANK1 is restricted to the cytoplasm where it interacts with Hrs and Alix marked endosomes. Collectively, our data demonstrate that the TnBVANK1 protein acts as a virulence factor that causes the disruption of ecdysone biosynthesis and developmental arrest by impairing the vesicular traffic of ecdysteroid precursors in the prothoracic gland steroidogenic cells.
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Affiliation(s)
- Luca Valzania
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
| | - Patrizia Romani
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
| | - Ling Tian
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai, China
| | - Sheng Li
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai, China
| | - Valeria Cavaliere
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
| | - Francesco Pennacchio
- Dipartimento di Agraria – Laboratorio di Entomologia “E. Tremblay”, Università di Napoli ‘Federico II’, Portici (NA), Italy
| | - Giuseppe Gargiulo
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
- * E-mail:
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11
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Gueguen G, Kalamarz ME, Ramroop J, Uribe J, Govind S. Polydnaviral ankyrin proteins aid parasitic wasp survival by coordinate and selective inhibition of hematopoietic and immune NF-kappa B signaling in insect hosts. PLoS Pathog 2013; 9:e1003580. [PMID: 24009508 PMCID: PMC3757122 DOI: 10.1371/journal.ppat.1003580] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 07/07/2013] [Indexed: 12/04/2022] Open
Abstract
Polydnaviruses are mutualists of their parasitoid wasps and express genes in immune cells of their Lepidopteran hosts. Polydnaviral genomes carry multiple copies of viral ankyrins or vankyrins. Vankyrin proteins are homologous to IκB proteins, but lack sequences for regulated degradation. We tested if Ichnoviral Vankyrins differentially impede Toll-NF-κB-dependent hematopoietic and immune signaling in a heterologous in vivo Drosophila, system. We first show that hematopoiesis and the cellular encapsulation response against parasitoid wasps are tightly-linked via NF-κB signaling. The niche, which neighbors the larval hematopoietic progenitors, responds to parasite infection. Drosophila NF-κB proteins are expressed in the niche, and non cell-autonomously influence fate choice in basal and parasite-activated hematopoiesis. These effects are blocked by the Vankyrin I2-vank-3, but not by P-vank-1, as is the expression of a NF-κB target transgene. I2-vank-3 and P-vank-1 differentially obstruct cellular and humoral inflammation. Additionally, their maternal expression weakens ventral embryonic patterning. We propose that selective perturbation of NF-κB-IκB interactions in natural hosts of parasitic wasps negatively impacts the outcome of hematopoietic and immune signaling and this immune deficit contributes to parasite survival and species success in nature. Parasitoid wasps are insects whose development takes place within the body of other insects. To survive, wasp larvae must overcome the immune defenses of their hosts. How parasitic wasps overcome host immunity is not fully understood even though we know that different strategies using venoms, virus-like particles, or viruses are involved. A unique class of viruses, called polydnaviruses is found in two families of wasps that comprise more than 20,000 wasp species. The genomes of polydnaviruses encode proteins with ankyrin repeats. Ankyrin repeats are also found in Cactus, the inhibitor protein of NF-κB signaling in Drosophila. Viral ankyrin proteins, or Vankyrins, however, lack the amino acid sequences necessary for turnover found in Cactus and mammalian IκB family members. We show that Vankyrins produced by polydnaviruses of a parasitic wasp that attacks caterpillars of many common agricultural pests can block NF-κB signaling in fruit fly larvae. This inhibition supports parasite success. Our work highlights the crucial role of NF-κB signaling across insect taxa in insect-insect and insect-virus interactions. Studies of polydnaviral ankyrin proteins in Drosophila reveal that immune-suppressive viruses may block both cellular and humoral immunity in insects to win the biological ‘arms race’.
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Affiliation(s)
- Gwenaelle Gueguen
- Biology Department, The City College of the City University of New York, New York, New York, United States of America
| | - Marta E. Kalamarz
- Biology Department, The City College of the City University of New York, New York, New York, United States of America
- The Graduate Center of the City University of New York, New York, New York, United States of America
| | - Johnny Ramroop
- Biology Department, The City College of the City University of New York, New York, New York, United States of America
- The Graduate Center of the City University of New York, New York, New York, United States of America
| | - Jeffrey Uribe
- Biology Department, The City College of the City University of New York, New York, New York, United States of America
| | - Shubha Govind
- Biology Department, The City College of the City University of New York, New York, New York, United States of America
- The Graduate Center of the City University of New York, New York, New York, United States of America
- * E-mail:
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12
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Gill TA, Webb BA. Analysis of gene transcription and relative abundance of the cys-motif gene family from Campoletis sonorensis ichnovirus (CsIV) and further characterization of the most abundant cys-motif protein, WHv1.6. Insect Mol Biol 2013; 22:341-353. [PMID: 23614457 DOI: 10.1111/imb.12022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The cys-motif gene family associated with Campoletis sonorensis ichnovirus contains 10 members, WHv1.6, WHv1.0, VHv1.1, VHv1.4, AHv1.0, A'Hv0.8, FHv1.4, LHv2.8, UHv0.8, and UHv0.8a. The results of this study indicated that, within the encapsidated virion, WHv1.6 is the most abundant cys-motif gene, while the combined AHv genes are the least abundant. During parasitization of Heliothis virescens by Campoletis sonorenis, WHv1.6 transcripts were the mostly highly expressed, while the combined UHv genes had the lowest expression. Further proteomic analysis of WHv1.6 showed that it accumulates at high levels in parasitized plasma by 6 h, and is detectable in the haemocytes, fat body, malpighian tubules, nerve cord and epidermis by 2 days after parasitization. Localization experiments led us to conclude that WHv1.6 interacts with the cell membrane along with other organelles within a virus-infected cell and prevents immunocytes from spreading or adhering to a foreign surface. Similarly to VHv1.4 and VHv1.1, WHv1.6 is able to inhibit the translation of haemocyte and Malpighian tubule RNAs. Our results showed that the expression of cys-motif genes during parasitization is related to the gene copy number of each gene within the encapsidated virion and may also be dependent upon cis-regulatory element activity in different target tissues. In addition, WHv1.6 plays a major role in inhibiting the cellular encapsulation response by H. virescens.
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Affiliation(s)
- T A Gill
- Department of Entomology, University of Kentucky, Lexington, KY 40503, USA
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Provost B, Jouan V, Hilliou F, Delobel P, Bernardo P, Ravallec M, Cousserans F, Wajnberg E, Darboux I, Fournier P, Strand MR, Volkoff AN. Lepidopteran transcriptome analysis following infection by phylogenetically unrelated polydnaviruses highlights differential and common responses. Insect Biochem Mol Biol 2011; 41:582-591. [PMID: 21457783 DOI: 10.1016/j.ibmb.2011.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 03/16/2011] [Accepted: 03/20/2011] [Indexed: 05/30/2023]
Abstract
The Polydnaviridae is a family of double-stranded DNA viruses that are symbionts of parasitoid wasps. The family is currently divided into two genera, the Ichnovirus (IV) and Bracovirus (BV), which are associated with wasps in the families Ichneumonidae and Braconidae, respectively. IVs and BVs have similar immunosuppressive and developmental effects on parasitized hosts but their encapsidated genomes largely encode different genes. To assess whether IV and BV infection has similar or disparate effects on the transcriptome of shared hosts, we characterized the effects of Hyposoter didymator Ichnovirus (HdIV) and Microplitis demolitor Bracovirus (MdBV) on the fat body and hemocyte transcriptome of Spodoptera frugiperda (Lepidoptera: Noctuidae). Our results indicated that HdIV and MdBV infection alters the abundance of a relatively low proportion of S. frugiperda transcripts at 24 h post-infection. A majority of the transcripts affected by infection also differed between MdBV and HdIV. However, we did identify some host transcripts that were similarly affected by both viruses. A majority of these genes were transcribed in the fat body and most belonged to functional classes with roles in immunity, detoxification, or cell structure. Particularly prominent in this suite of transcripts were genes encoding for predicted motor-related and collagen IV-like proteins. Overall, our data suggest that the broadly similar effects that HdIV and MdBV have on host growth and immunity are not due to these viruses inducing profound changes in host gene expression. Given though that IVs and BVs encode few shared genes, the host transcripts that are similarly affected by HdIV and MdBV could indicate convergence by each virus to target a few processes at the level of transcription that are important for successful parasitism of hosts by H. didymator and M. demolitor.
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Affiliation(s)
- Bertille Provost
- UMR1333, INRA, Université Montpellier 2, Place Eugène Bataillon, cc101, F-34095 Montpellier Cedex 5, France
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14
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Kim J, Kim Y. A viral histone H4 suppresses expression of a transferrin that plays a role in the immune response of the diamondback moth, Plutella xylostella. Insect Mol Biol 2010; 19:567-574. [PMID: 20491980 DOI: 10.1111/j.1365-2583.2010.01014.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A transferrin (Tf) gene has been predicted from an expressed sequence tag of the diamondback moth, Plutella xylostella. It encodes 681 amino acid residues that share 80-90% sequence homologies with other lepidopteran Tfs. The gene was constitutively expressed in all developmental stages of P. xylostella. Double-stranded RNA (dsRNA) specific to the Tf gene was prepared and microinjected into the larvae. We hypothesize that the dsRNA treatment suppressed the Tf gene expression level and it significantly inhibited haemocyte nodule formation in response to bacterial challenge. The larvae treated with dsRNA also showed a significantly enhanced susceptibility to an entomopathogenic bacterium, Bacillus thuringiensis. An endoparasitoid wasp, Cotesia plutellae, parasitized the larvae of P. xylostella, which showed significant reduction of Tf expression. The suppression of Tf expression was mimicked by transient expression of a viral gene CpBV-H4, encoded in the symbiotic virus of C. plutellae. A truncated form of CpBV-H4 prepared by deleting an extended N-terminal 38 amino acid residue lost its inhibitory activity against the Tf gene expression. These results suggest that Tf of P. xylostella plays an immunological role in P. xylostella and that the suppression of its expression in the parasitized larvae is caused by a viral histone H4 in an epigenetic mode.
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Affiliation(s)
- J Kim
- School of Bioresource Sciences, Andong National University, Andong, Korea
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15
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Lu Z, Beck MH, Strand MR. Egf1.5 is a second phenoloxidase cascade inhibitor encoded by Microplitis demolitor bracovirus. Insect Biochem Mol Biol 2010; 40:497-505. [PMID: 20417280 DOI: 10.1016/j.ibmb.2010.04.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 04/04/2010] [Accepted: 04/07/2010] [Indexed: 05/29/2023]
Abstract
The three-member Egf gene family from the polydnavirus Microplitis demolitor bracovirus (MdBV) encodes novel proteins distinguished by a shared cysteine-rich motif. Prior studies determined that one family member, Egf1.0, inhibits melanization of hemolymph from the moth Manduca sexta by disabling phenoloxidase activating proteinases (PAPs). Here we characterized a second family member, Egf1.5, which shares an identical cysteine-rich motif with Egf1.0, but possesses an extended C-terminal repeat domain. Similar to Egf1.0, Egf1.5 inhibited processing and the amidolytic activity of PAP1 and PAP3 from M. sexta. Egf1.5 also bound PAP1, PAP3 and serine proteinase homolog 2 (SPH2). Comparative studies indicated that Egf1.5 and Egf1.0 similarly inhibited melanization of plasma from two lepidopterans (Pseudoplusia includens and Helicoverpa zea) that are permissive hosts for M. demolitor and MdBV, and two lepidopterans (M. sexta and Bombyx mori) that are nonpermissive hosts. Expression studies showed that transcript abundance of egf1.5 and egf1.0 was also similar in MdBV-infected P. includens and H. zea. Taken together, our results indicate that Egf1.5 and Egf1.0 are functionally similar paralogs.
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Affiliation(s)
- Zhiqiang Lu
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
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16
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Gad W, Kim Y. N-terminal tail of a viral histone H4 encoded in Cotesia plutellae bracovirus is essential to suppress gene expression of host histone H4. Insect Mol Biol 2009; 18:111-118. [PMID: 19196351 DOI: 10.1111/j.1365-2583.2009.00860.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
An endoparasitoid wasp, Cotesia plutellae, possesses a symbiotic bracovirus (CpBV), which facilitates parasitism of a specific host, such as larvae of the diamondback moth, Plutella xylostella. A viral histone H4 (CpBV-H4) has been found in the CpBV genome and its gene product plays a role in impairing the host insect cellular immune response. Based on its high similarity to histone H4 of P. xylostella apart from its extended N-terminal tail, it has been suspected to alter host gene expression. Histone subunits were purified from parasitized P. xylostella larvae and found to contain both host and viral H4s, confirming a previous report of a possible epigenetic mode of action. Moreover, this study showed that the host H4 levels in the parasitized larvae clearly decreased during the parasitization period, whereas CpBV-H4 levels maintained a significant level without significant changes. To understand the decrease of host H4 levels, transcription levels of host H4 were monitored by quantitative reverse-transcriptase PCR (RT-PCR) and showed a significant decrease in parasitized P. xylostella larvae, whereas no significant change of the mRNA level was detected in nonparasitized larvae. This transcriptional control of host H4 expression was also observed by inducing transient expression of CpBV-H4 in nonparasitized P. xylostella. Moreover, co-injection of CpBV-H4 and its specific double-stranded RNA recovered the host H4 expression level. To identify a functional domain of CpBV-H4 involved in the transcriptional control, the extended N-terminal tail of CpBV-H4 was removed by preparing a truncated viral H4 construct in an expression vector by deleting the N-terminal tail of 38 amino acid residues and inducing its expression in nonparasitized P. xylostella larvae. The truncated CpBV-H4 clearly lost its inhibitory effects on host H4 transcription. Moreover, the presence of CpBV-H4 affects the spreading of host haemocytes by an epigenetic effect, which is at least partly restored in larvae expressing the truncated version of CpBV-H4. This study suggests that the viral H4 encoded in CpBV can alter host gene expression with its extended N-terminal tail.
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Affiliation(s)
- W Gad
- Department of Bioresource Sciences, Andong National University, Andong, Korea
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Chen YF, Shi M, Liu PC, Huang F, Chen XX. Characterization of an IkappaB-like gene in Cotesia vestalis polydnavirus. Arch Insect Biochem Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Falabella P, Varricchio P, Provost B, Espagne E, Ferrarese R, Grimaldi A, de Eguileor M, Fimiani G, Ursini MV, Malva C, Drezen JM, Pennacchio F. Characterization of the IkappaB-like gene family in polydnaviruses associated with wasps belonging to different Braconid subfamilies. J Gen Virol 2007; 88:92-104. [PMID: 17170441 DOI: 10.1099/vir.0.82306-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polydnaviruses (PDVs) are obligate symbionts of hymenopteran parasitoids of lepidopteran larvae that induce host immunosuppression and physiological redirection. PDVs include bracoviruses (BVs) and ichnoviruses (IVs), which are associated with braconid and ichneumonid wasps, respectively. In this study, the gene family encoding IkappaB-like proteins in the BVs associated with Cotesia congregata (CcBV) and Toxoneuron nigriceps (TnBV) was analysed. PDV-encoded IkappaB-like proteins (ANK) are similar to insect and mammalian IkappaB, an inhibitor of the transcription factor nuclear factor kappaB (NF-kappaB), but display shorter ankyrin domains and lack the regulatory domains for signal-mediated degradation and turnover. Phylogenetic analysis of ANK proteins indicates that those of IVs and BVs are closely related, even though these two taxa are believed to lack a common ancestor. Starting from a few hours after parasitization, the transcripts of BV ank genes were detected, at different levels, in several host tissues. The structure of the predicted proteins suggests that they may stably bind NF-kappaB/Rel transcription factors of the tumour necrosis factor (TNF)/Toll immune pathway. Accordingly, after bacterial challenge of Heliothis virescens host larvae parasitized by T. nigriceps, NF-kappaB immunoreactive material failed to enter the nucleus of host haemocytes and fat body cells. Moreover, transfection experiments in human HeLa cells demonstrated that a TnBV ank1 gene product reduced the efficiency of the TNF-alpha-induced expression of a reporter gene under NF-kappaB transcriptional control. Altogether, these results suggest strongly that TnBV ANK proteins cause retention of NF-kappaB/Rel factors in the cytoplasm and may thus contribute to suppression of the immune response in parasitized host larvae.
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Affiliation(s)
- Patrizia Falabella
- Dipartimento di Biologia, Difesa e Biotecnologie Agro-Forestali, Università della Basilicata, Potenza, Italy
| | | | - Bertille Provost
- Institut de Recherche sur la Biologie de l'Insecte, CNRS, Université de Tours, Faculté des Sciences, Tours, France
| | - Eric Espagne
- Institut de Recherche sur la Biologie de l'Insecte, CNRS, Université de Tours, Faculté des Sciences, Tours, France
| | - Roberto Ferrarese
- Dipartimento di Biologia Strutturale e Funzionale, Università dell'Insubria, Varese, Italy
| | - Annalisa Grimaldi
- Dipartimento di Biologia Strutturale e Funzionale, Università dell'Insubria, Varese, Italy
| | - Magda de Eguileor
- Dipartimento di Biologia Strutturale e Funzionale, Università dell'Insubria, Varese, Italy
| | | | | | - Carla Malva
- Istituto di Genetica e Biofisica, CNR, Napoli, Italy
| | - Jean-Michel Drezen
- Institut de Recherche sur la Biologie de l'Insecte, CNRS, Université de Tours, Faculté des Sciences, Tours, France
| | - Francesco Pennacchio
- Dipartimento di Entomologia e Zoologia Agraria 'F. Silvestri', Università di Napoli 'Federico II', Via Università 100, 80055 Portici (NA), Italy
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Galibert L, Devauchelle G, Cousserans F, Rocher J, Cérutti P, Barat-Houari M, Fournier P, Volkoff AN. Members of the Hyposoter didymator Ichnovirus repeat element gene family are differentially expressed in Spodoptera frugiperda. Virol J 2006; 3:48. [PMID: 16784535 PMCID: PMC1539012 DOI: 10.1186/1743-422x-3-48] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Accepted: 06/19/2006] [Indexed: 11/10/2022] Open
Abstract
Background The abundance and the conservation of the repeated element (rep) genes in Ichnoviruses genomes suggest that this gene family plays an important role in viral cycles. In the Ichnovirus associated with the wasp Hyposoter didymator, named HdIV, 10 rep genes were identified to date. In this work, we report a relative quantitative transcription study of these HdIV rep genes in several tissues of the lepidopteran host Spodoptera frugiperda as well as in the H. didymator wasps. Results The data obtained in this work indicate that, in the early phases of infection (24 hours), HdIV rep genes each display different levels of transcripts in parasitized 2nd instar or HdIV-injected last instar S. frugiperda larvae. Only one, rep1, is significantly transcribed in female wasps. Transcript levels of the HdIV rep genes were found as not correlated to their copy number in HdIV genome. Our results also show that HdIV rep genes display different tissue specificity, and that they are primarily transcribed in S. frugiperda fat body and cuticular epithelium. Conclusion This work is the first quantitative analysis of transcription of the ichnovirus rep gene family, and the first investigation on a correlation between transcript levels and gene copy numbers in Ichnoviruses. Our data indicate that, despite similar gene copy numbers, not all the members of this gene family are significantly transcribed 24 hours after infection in lepidopteran larvae. Additionally, our data show that, as opposed to other described HdIV genes, rep genes are little transcribed in hemocytes, thus suggesting that they are not directly associated with the disruption of the immune response but rather involved in other physiological alterations of the infected lepidopteran larva.
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Affiliation(s)
- L Galibert
- UMR1231 INRA-UMII Biologie Intégrative et Virologie des Insectes (BIVI), Place Eugène Bataillon, Case Courrier 101, 34 095 Montpellier Cédex5, France
| | - G Devauchelle
- UMR 5160 CNRS-UMI Baculovirus et Thérapie, 30 380 Saint Christol-lez-Alès, France
| | - F Cousserans
- UMR1231 INRA-UMII Biologie Intégrative et Virologie des Insectes (BIVI), Place Eugène Bataillon, Case Courrier 101, 34 095 Montpellier Cédex5, France
| | - J Rocher
- UMR1231 INRA-UMII Biologie Intégrative et Virologie des Insectes (BIVI), Place Eugène Bataillon, Case Courrier 101, 34 095 Montpellier Cédex5, France
| | - P Cérutti
- UMR 5160 CNRS-UMI Baculovirus et Thérapie, 30 380 Saint Christol-lez-Alès, France
| | - M Barat-Houari
- UMR1231 INRA-UMII Biologie Intégrative et Virologie des Insectes (BIVI), Place Eugène Bataillon, Case Courrier 101, 34 095 Montpellier Cédex5, France
| | - P Fournier
- UMR1231 INRA-UMII Biologie Intégrative et Virologie des Insectes (BIVI), Place Eugène Bataillon, Case Courrier 101, 34 095 Montpellier Cédex5, France
| | - AN Volkoff
- UMR1231 INRA-UMII Biologie Intégrative et Virologie des Insectes (BIVI), Place Eugène Bataillon, Case Courrier 101, 34 095 Montpellier Cédex5, France
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20
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Asgari S. Venom proteins from polydnavirus-producing endoparasitoids: their role in host-parasite interactions. Arch Insect Biochem Physiol 2006; 61:146-56. [PMID: 16482579 DOI: 10.1002/arch.20109] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Endoparasitoid wasps have evolved various mechanisms to ensure successful development of their progeny, including co-injection of a cocktail of maternal secretions into the host hemocoel, including venom, calyx fluid, and polydnaviruses. The components of each type of secretion may influence host physiology and development independently or in a synergistic fashion. For example, venom fluid consists of several peptides and proteins that promote expression of polydnavirus genes in addition to other activities, such as inhibition of prophenoloxidase activation, inhibition of hemocytes spreading and aggregation, and inhibition of development. This review provides a brief overview of advances and prospects in the study of venom proteins from polydnavirus-producing endoparasitoid wasps with a special emphasis on the role of C. rubecula venom proteins in host-parasitoid interactions.
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Affiliation(s)
- Sassan Asgari
- School of Integrative Biology, University of Queensland, St. Lucia, Queensland, Australia.
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Espagne E, Douris V, Lalmanach G, Provost B, Cattolico L, Lesobre J, Kurata S, Iatrou K, Drezen JM, Huguet E. A virus essential for insect host-parasite interactions encodes cystatins. J Virol 2005; 79:9765-76. [PMID: 16014938 PMCID: PMC1181612 DOI: 10.1128/jvi.79.15.9765-9776.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cotesia congregata is a parasitoid wasp that injects its eggs in the host caterpillar Manduca sexta. In this host-parasite interaction, successful parasitism is ensured by a third partner: a bracovirus. The relationship between parasitic wasps and bracoviruses constitutes one of the few known mutualisms between viruses and eukaryotes. The C. congregata bracovirus (CcBV) is injected at the same time as the wasp eggs in the host hemolymph. Expression of viral genes alters the caterpillar's immune defense responses and developmental program, resulting in the creation of a favorable environment for the survival and emergence of adult parasitoid wasps. Here, we describe the characterization of a CcBV multigene family which is highly expressed during parasitism and which encodes three proteins with homology to members of the cystatin superfamily. Cystatins are tightly binding, reversible inhibitors of cysteine proteases. Other cysteine protease inhibitors have been described for lepidopteran viruses; however, this is the first description of the presence of cystatins in a viral genome. The expression and purification of a recombinant form of one of the CcBV cystatins, cystatin 1, revealed that this viral cystatin is functional having potent inhibitory activity towards the cysteine proteases papain, human cathepsins L and B and Sarcophaga cathepsin B in assays in vitro. CcBV cystatins are, therefore, likely to play a role in host caterpillar physiological deregulation by inhibiting host target proteases in the course of the host-parasite interaction.
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Affiliation(s)
- E Espagne
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 6035, Faculté des Sciences et Techniques, Parc de Grandmont, Tours
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23
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Kroemer JA, Webb BA. Ikappabeta-related vankyrin genes in the Campoletis sonorensis ichnovirus: temporal and tissue-specific patterns of expression in parasitized Heliothis virescens lepidopteran hosts. J Virol 2005; 79:7617-28. [PMID: 15919914 PMCID: PMC1143682 DOI: 10.1128/jvi.79.12.7617-7628.2005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Polydnaviruses (PDVs) are unusual insect viruses that occur in obligate symbiotic associations with parasitic ichneumonid (ichnoviruses, or IVs) and braconid (bracoviruses, or BVs) wasps. PDVs are injected with eggs, ovarian proteins, and venom during parasitization. Following infection of cells in host tissues, viral genes are expressed and their products function to alter lepidopteran host physiology, enabling endoparasitoid development. Here we describe the Campoletis sonorensis IV viral ankyrin (vankyrin) gene family and its transcription. The seven members of this gene family possess ankyrin repeat domains that resemble the inhibitory domains of the Drosophila melanogaster NF-kappabeta transcription factor inhibitor (Ikappabeta) cactus. vankyrin gene expression is detected within 2 to 4 h postparasitization (p.p.) in Heliothis virescens hosts and reaches peak levels by 3 days p.p. Our data indicate that vankyrin genes from the C. sonorensis IV genome are differentially expressed in the tissues of parasitized hosts and can be divided into two subclasses: those that target the host fat body and those that target host hemocytes. Polyclonal antibodies raised against a fat-body targeting vankyrin detected a 19-kDa protein in crude extracts prepared from the 3 days p.p. fat body. Vankyrin-specific Abs localized to 3-day p.p. fat-body and hemocyte nuclei, suggesting a role for vankyrin proteins in the nuclei of C. sonorensis IV-infected cells. These data are evidence for divergent tissue specificities and targeting of multigene families in IVs. We hypothesize that PDV vankyrin genes may suppress NF-kappabeta activity during immune responses and developmental cascades in parasitized lepidopteran hosts of C. sonorensis.
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Affiliation(s)
- Jeremy A Kroemer
- University of Kentucky, Department of Entomology, S-225 Agricultural Sciences Center North, Lexington, KY 40546, USA
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24
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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25
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Lapointe R, Wilson R, Vilaplana L, O'Reilly DR, Falabella P, Douris V, Bernier-Cardou M, Pennacchio F, Iatrou K, Malva C, Olszewski JA. Expression of a Toxoneuron nigriceps polydnavirus-encoded protein causes apoptosis-like programmed cell death in lepidopteran insect cells. J Gen Virol 2005; 86:963-971. [PMID: 15784889 DOI: 10.1099/vir.0.80834-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The polydnavirus Toxoneuron nigriceps bracovirus (TnBV) is an obligate symbiont associated with the braconid wasp T. nigriceps, a parasitoid of Heliothis virescens larvae. Previously, to identify polydnavirus genes that allow parasitization by altering the host immune and endocrine systems, expression patterns of TnBV genes from parasitized H. virescens larvae were analysed and cDNAs were obtained. To study the function of the protein from one such cDNA, TnBV1, overexpression of the protein was attempted by using the baculovirus Autographa californica multicapsid nucleopolyhedrovirus. Recovery of stable recombinant virus was unsuccessful, with the exception of recombinants with deletions/mutations within the TnBV1 gene. It was hypothesized that TnBV1 expression was cytotoxic to the Spodoptera frugiperda (Sf21) insect cells that were used to produce the recombinants. Therefore, the Bac-to-Bac system was used to create recombinant baculoviruses maintained in Escherichia coli expressing either TnBV1 (Ac-TnBV1) or an initiator-methionine mutant [Ac-TnBV1(ATG−)]. Microscopy revealed substantial cell death of Sf21 and High Five cells from 48 h post-infection with Ac-TnBV1, but not with the Ac-TnBV1(ATG−) recombinant virus. Ac-TnBV1-infected Sf21 cells, but not those with parental virus infection, showed an increased caspase-3-like protease activity, as well as increased terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling (TUNEL) for breaks in host genomic DNA. Although indicative of apoptosis, blebbing and apoptotic bodies were not observed in infected cells. Transiently expressing TnBV1 alone caused TUNEL staining in High Five cells. These data suggest that TnBV1 expression alone can induce apoptosis-like programmed cell death in two insect cell lines. Injection of Ac-TnBV1 budded virus, compared with parental virus, did not result in an alteration of virulence in H. virescens larvae.
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Affiliation(s)
- Renée Lapointe
- Department of Biological Sciences, Imperial College, London SW7 2AZ, UK
| | - Rebecca Wilson
- Department of Biological Sciences, Imperial College, London SW7 2AZ, UK
| | - Lluïsa Vilaplana
- Department of Biological Sciences, Imperial College, London SW7 2AZ, UK
| | - David R O'Reilly
- Department of Biological Sciences, Imperial College, London SW7 2AZ, UK
| | - Patrizia Falabella
- Dipartimento di Biologia, Difesa e Biotecnologie, Agro-Forestali-Università della Basilicata-Macchia Romana, 85100 Potenza, Italy
| | - Vassilis Douris
- National Centre for Scientific Research 'Demokritos', 153 10 Aghia Paraskevi, Athens, Greece
| | - Michèle Bernier-Cardou
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Sainte-Foy (Québec), Canada G1V 4C7
| | - Francesco Pennacchio
- Dipartimento di Biologia, Difesa e Biotecnologie, Agro-Forestali-Università della Basilicata-Macchia Romana, 85100 Potenza, Italy
| | - Kostas Iatrou
- National Centre for Scientific Research 'Demokritos', 153 10 Aghia Paraskevi, Athens, Greece
| | - Carla Malva
- Instituto di Genetica e Biofisica, CNR, Via Pietro Castellino 111, 80131 Napoli, Italy
| | - Julie A Olszewski
- Department of Biological Sciences, Imperial College, London SW7 2AZ, UK
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26
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Abstract
Polydnaviridae is a unique family of DNA viruses that are symbiotically associated with parasitoid wasps. Upon oviposition, wasps inject these viruses into their hosts, where they cause several physiological alterations, including suppression of the cellular immune response. Here we report that expression of the glc1.8 gene from Microplitis demolitor bracovirus (MdBV) causes a loss of adhesion by two hemocyte-like cell lines, namely, High Five cells from the lepidopteran Trichoplusia ni and S2 cells from the dipteran Drosophila melanogaster. The expression of recombinant Glc1.8 also greatly reduced the ability of these cells to phagocytize foreign targets. Glc1.8 is characterized by a signal peptide at its N terminus, an extracellular domain comprised of five nearly perfect tandem repeats of 78 amino acids, and a C-terminal hydrophobic domain that encodes a putative membrane anchor sequence. The expression of a Glc1.8 mutant lacking the anchor sequence resulted in a secreted protein that had no effect on adhesion or phagocytosis. In contrast, sequential deletion of the repeats in the extracellular domain resulted in a progressive reduction in immunosuppressive activity. Since each repeat and its associated glycosylation sites are nearly identical, these results suggested that adhesion-blocking activity depends more on the overall number of repeats in the extracellular domain than on the specific determinants within each repeat. While it severely compromised adhesion and phagocytic functions, Glc1.8 did not cause cell death. Collectively, these results indicate that Glc1.8 is a major pathogenic determinant of MdBV that is involved in suppression of the insect cellular immune response.
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Affiliation(s)
- Markus Beck
- Department of Entomology, 413 Biological Sciences Bldg., University of Georgia, Athens, GA 30602, USA
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27
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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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28
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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29
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Glatz R, Schmidt O, Asgari S. Characterization of a novel protein with homology to C-type lectins expressed by the Cotesia rubecula bracovirus in larvae of the lepidopteran host, Pieris rapae. J Biol Chem 2003; 278:19743-50. [PMID: 12644452 DOI: 10.1074/jbc.m301396200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polydnaviruses are essential for the survival of many Ichneumonoid endoparasitoids, providing active immune suppression of the host in which parasitoid larvae develop. The Cotesia rubecula bracovirus is unique among polydnaviruses in that only four major genes are detected in parasitized host (Pieris rapae) tissues, and gene expression is transient. Here we describe a novel C. rubecula bracovirus gene (CrV3) encoding a lectin monomer composed of 159 amino acids, which has conserved residues consistent with invertebrate and mammalian C-type lectins. Bacterially expressed CrV3 agglutinated sheep red blood cells in a divalent ion-dependent but Ca2+-independent manner. Agglutination was inhibited by EDTA but not by biological concentrations of any saccharides tested. Two monomers of approximately 14 and approximately 17 kDa in size were identified on SDS-PAGE in parasitized P. rapae larvae. The 17-kDa monomer was found to be an N-glyscosylated form of the 14-kDa monomer. CrV3 is produced in infected hemocytes and fat body cells and subsequently secreted into hemolymph. We propose that CrV3 is a novel lectin, the first characterized from an invertebrate virus. CrV3 shows over 60% homology with hypothetical proteins isolated from polydnaviruses in two other Cotesia wasps, indicating that these proteins may also be C-type lectins and that a novel polydnavirus lectin family exists in Cotesia-associated bracoviruses. CrV3 is probably interacting with components in host hemolymph, resulting in suppression of the Pieris immune response. The high similarity of CrV3 with invertebrate lectins, as opposed to those from viruses, may indicate that some bracovirus functions were acquired from their hosts.
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Affiliation(s)
- Richard Glatz
- Department of Applied and Molecular Ecology, Waite Campus, The University of Adelaide, Glen Osmond, South Australia 5064, Australia
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30
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Asgari S, Zhang G, Schmidt O. Polydnavirus particle proteins with similarities to molecular chaperones, heat-shock protein 70 and calreticulin. J Gen Virol 2003; 84:1165-1171. [PMID: 12692281 DOI: 10.1099/vir.0.19026-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Multipartite nucleic acid-containing virus-like particles, known as polydnaviruses, are special structures produced by female parasitoid wasps to deliver wasp components into the body of their host at oviposition. The particles confer protection for the developing parasitoid by passive and active means. Although several genes expressed from the circular DNA of these particles have been identified from various host-parasitoid systems, there is not much known about the structural proteins of these particles. Here we report on two genes encoding Cotesia rubecula particle proteins with similarities to molecular chaperones, calreticulin and heat-shock protein 70.
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Affiliation(s)
- Sassan Asgari
- Department of Applied and Molecular Ecology, Waite Campus, The University of Adelaide, Glen Osmond, South Australia 5064, Australia
| | - Guangmei Zhang
- Department of Applied and Molecular Ecology, Waite Campus, The University of Adelaide, Glen Osmond, South Australia 5064, Australia
| | - Otto Schmidt
- Department of Applied and Molecular Ecology, Waite Campus, The University of Adelaide, Glen Osmond, South Australia 5064, Australia
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31
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Asgari S, Schmidt O. A coiled-coil region of an insect immune suppressor protein is involved in binding and uptake by hemocytes. Insect Biochem Mol Biol 2002; 32:497-504. [PMID: 11891126 DOI: 10.1016/s0965-1748(01)00127-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Polydnaviruses are associated with certain parasitoid wasps and are introduced into the body cavity of the host caterpillar during oviposition. Some of the viral genes are expressed in host tissues and corresponding proteins are secreted into the hemocoel causing suppression of the host immune system. The Cotesia rubecula polydnavirus gene product, CrV1, effectively inactivates hemocytes by mediating cytoskeleton breakdown. A precondition for the CrV1 function is the incorporation of the extracellular protein by hemocytes. Here, we show that a coiled-coil domain containing a putative leucine zipper is required for CrV1 function, since removal of this domain abolishes binding and uptake of the CrV1 protein by hemocytes.
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Affiliation(s)
- Sassan Asgari
- Department of Applied and Molecular Ecology, Waite Campus, Adelaide University, Glen Osmond, SA 5064, Australia.
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32
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Savary S, Beckage N, Tan F, Periquet G, Drezen JM. Excision of the polydnavirus chromosomal integrated EP1 sequence of the parasitoid wasp Cotesia congregata (Braconidae, Microgastinae) at potential recombinase binding sites. J Gen Virol 1997; 78 ( Pt 12):3125-34. [PMID: 9400960 DOI: 10.1099/0022-1317-78-12-3125] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cotesia congregata polydnavirus (CcPDV) is essential for successful parasitism of Manduca sexta larvae by the braconid wasp Cotesia congregata. To determine the molecular mechanisms for the vertical transmission of CcPDV in the wasps, we analysed the different forms of the virus sequences containing the gene encoding the early parasitism-specific protein 1 (EP1). By a detailed molecular analysis, we demonstrated that the EP1 sequences are present in wasp DNA in two forms: a circular form as seen in the virus particles and a form integrated into the wasp genome. Moreover, we showed that the integrated form of the EP1 sequences is able to excise in the ovary cells. A fragment corresponding to an EP1 'empty locus' (without the viral sequence) was PCR-amplified from ovarian DNA. Comparison of the sequences isolated from the EP1 circle, the integrated form and the empty locus revealed that the extremities of the EP1 genomic sequences constitute a direct repeat. Strikingly, these sequences contain a potential binding site for a recombinase of the Hin family located in close vicinity to the position where the DNA strand exchange occurs. Thus, the data bear upon the possibility that the bracovirus circles are excised via a mechanism related to the Hin mediated Conservative Specific-Specific Recombination (CSSR) of prokaryotes.
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Affiliation(s)
- S Savary
- Institut de Recherche sur la Biologie de l'Insecte-UPRESA CNRS 6035, Faculté des Sciences, Tours, France
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33
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Abstract
The molecular mechanism by which polydnaviruses of endoparasitoid wasps disrupt cell-mediated encapsulation reactions of host insects is largely unknown. Here we show that a polydnavirus-encoded protein, produced from baculovirus and plasmid expression vectors, prevents cell surface exposure of lectin-binding sites and microparticle formation during immune stimulation of haemocytes. The inactivation of immune-related cellular processes by this protein was analysed using a specific lectin and annexin V and shown to be virtually identical to polydnavirus-mediated effects on haemocytes. Cytochalasin D application has similar effects on haemocytes, suggesting that the immune suppression by the polydnavirus protein is caused by the destabilization of actin filaments. Since the exposure of cell surface glycoproteins and the formation of microparticles are part of an immune response to foreign objects or microorganisms and a prerequisite for cell-mediated encapsulation of microorganisms and parasites, the virus-encoded protein may become an important tool for the inactivation of cellular immune reactions in insects and an essential component in understanding immune suppression in parasitized host insects.
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Affiliation(s)
- S Asgari
- Department of Crop Protection, University of Adelaide, Glen Osmond, Australia
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Soldevila AI, Heuston S, Webb BA. Purification and analysis of a polydnavirus gene product expressed using a poly-histidine baculovirus vector. Insect Biochem Mol Biol 1997; 27:201-211. [PMID: 9090116 DOI: 10.1016/s0965-1748(96)00087-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The VHv1.1 polydnavirus gene has been implicated in suppressing the encapsulation response in parasitized insects [Li and Webb (1994) J. Virol. 68, 7482-7489]. In order to characterize this gene product and to further our analysis of its immunosuppressive function, we expressed the VHv1.1 using a custom-designed C-terminal poly-histidine baculovirus vector which allows for high expression and single-step purification of the protein. The 34 kDa VHv1.1 protein was expressed in baculovirus-infected cell cultures and in H. virescens larvae. Highly enriched preparations of the secreted VHv1.1 protein were obtained after affinity chromatography using a NTA-(Ni2+) resin. Characterization with purified preparations of the VHv1.1 protein established that the protein is N-glycosylated, containing glycogroups which are PNGase F-sensitive but Endo H-resistant. The recombinant VHv1.1 protein bound to hemocytes in vitro and in vivo and was endocytosed in a manner similar to the native protein produced in CsPDV-infected larvae.
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Affiliation(s)
- A I Soldevila
- Department of Entomology, University of Kentucky, Lexington 40546, USA
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