1
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Lye PY, Shiraki C, Fukushima Y, Takaki K, Liew MWO, Yamamoto M, Wakabayashi K, Mori H, Kotani E. Cytotoxin-mediated silk gland organ dysfunction diverts resources to enhance silkworm fecundity by potentiating nutrient-sensing IIS/TOR pathways. iScience 2024; 27:108853. [PMID: 38303707 PMCID: PMC10830876 DOI: 10.1016/j.isci.2024.108853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 11/16/2023] [Accepted: 01/05/2024] [Indexed: 02/03/2024] Open
Abstract
Energy reserves, primarily stored in the insect's fat body, are essential for physiological processes such as reproduction and cocoon formation. However, whether these processes are mutually constraining is unknown. Here, we showed that cocoon-free silkworms accumulate amino acid constituents of silk proteins in the hemolymph and maintain lipid and sugar reserves in the pupal fat body by repressing the expression of sericin and fibroin genes in the middle and posterior silk glands, respectively, via butterfly pierisin-1A catalytic domain expression. This, in turn, upregulates insulin/insulin-like signaling and target of rapamycin (IIS/TOR) signaling, which enhances vitellogenesis and accelerates ovarian development, thus contributing to increased fecundity. The impacts of semi-starvation on fecundity and egg hatchability were also less pronounced in cocoon-free silkworms compared with wildtype silkworms. These data uncover the resource allocation trade-off between cocoon formation and fecundity and demonstrate that nutritional signaling plays a role in regulating silkworm reproduction.
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Affiliation(s)
- Ping Ying Lye
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Chika Shiraki
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Yuta Fukushima
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Keiko Takaki
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
- Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mervyn Wing On Liew
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia
| | - Masafumi Yamamoto
- ICLAS Monitoring Center, Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki 210-0821, Japan
| | - Keiji Wakabayashi
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Hajime Mori
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Eiji Kotani
- Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
- Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
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2
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Xu J, Xie X, Ma Q, Zhang L, Li Y, Chen Y, Li K, Xiao Y, Tettamanti G, Xu H, Tian L. Identification of Host Molecules Involved in the Proliferation of Nucleopolyhedrovirus in Bombyx mori. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:14427-14438. [PMID: 36321811 DOI: 10.1021/acs.jafc.2c06758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The Bombyx mori nucleopolyhedrovirus (BmNPV), a foodborne infectious virus, is the pathogen causing nuclear polyhedrosis and high lethality in the silkworm. In this study, we characterized the molecules involved in BmNPV-silkworm interaction by RNA sequencing of the fat body isolated from the virus-susceptible strain P50. Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation showed that the upregulated differentially expressed genes (DEGs) were mainly involved in translation, signal transduction, folding, sorting, and degradation, as well as transport and catabolism, while the downregulated DEGs were predominantly enriched in the metabolism of carbohydrates, amino acids, and lipids at 72 h post BmNPV infection. Knockout of the upregulated somatomedin-B and thrombospondin type-1 domain-containing protein, probable allantoicase, trifunctional purine biosynthetic protein adenosine-3, and Psl and pyoverdine operon regulator inhibited the proliferation of BmNPV, while knockout of the downregulated clip domain serine protease 3 and carboxylesterase clade H, member 1 promoted it. The molecules herein identified provide a foundation for developing strategies and designing drugs against BmNPV.
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Affiliation(s)
- Jing Xu
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
- Henry Fok School of Biology and Agriculture, Shaoguan University, Shaoguan 512005, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, China
| | - Xiaole Xie
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Qiuqin Ma
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Lu Zhang
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Yu Li
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Yin Chen
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Kang Li
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Yang Xiao
- The Sericultural and Agri-Food Research Institute of the Guangdong Academy of Agricultural Sciences, Guangzhou 510507, China
| | - Gianluca Tettamanti
- Department of Biotechnology and Life Sciences, University of Insubria, Varese 21100, Italy
- Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology (BAT Center), University of Napoli Federico II, 80055 Portici, Italy
| | - Hanhong Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, China
| | - Ling Tian
- Guangdong Laboratory for Lingnan Modern Agriculture/Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
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3
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Khajje D, Devi SS, Subrahmanyam G, Kobayashi J, Sivaprasad V, Terenius O, Ponnuvel KM. Investigation on Pathological Aspects, Mode of Transmission, and Tissue Tropism of Antheraea proylei Nucleopolyhedrovirus Infecting Oak Tasar Silkworm. JOURNAL OF INSECT SCIENCE (ONLINE) 2022; 22:9. [PMID: 36208151 PMCID: PMC9543400 DOI: 10.1093/jisesa/ieac057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Indexed: 06/16/2023]
Abstract
The temperate oak tasar silkworm, Antheraea proylei, is frequently infested with Antheraea proylei nucleopolyhedrovirus (AnprNPV) causing tiger band disease. This disease is one of the key factors that obstructs production and productivity of oak tasar sericulture. The current study aimed to investigate the pathogenicity of AnprNPV, its mode of transmission, and detection of AnprNPV in different tissues. Transmission electron micrographs of AnprNPV showed single rod-shaped bodies and occlusion derived virus (ODV) enclosed within multiple envelopes. The infecting AnprNPV displayed tissue tropism with higher copy numbers detected in the insect fat body and ovary. The virus was observed to multiply in all developmental stages of the silkworm such as egg, larva, pupa, and moth, confirming its ability to spread throughout the silkworm lifecycle. Baculovirus isolated from infected A. proylei showed cross-infectivity in other Saturniidae wild silkworm species such as Antheraea pernyi, A. frithi, and Samia ricini, widening their probable host range for infection. Baculoviruses generally display a horizontal mode of transmission, mainly through ingestion of occlusion bodies (OBs); however, the present study revealed a trans-ovum vertical mode of transmission in addition to a horizontal mode. The observations made in this study aid a detailed understanding of the tiger band disease and its causative pathogen AnprNPV, which will support future studies and disease management in oak tasar sericulture.
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Affiliation(s)
- Diksha Khajje
- Genomic Division, Seri biotech Research Laboratory, Carmelaram Post, Kodathi, Bangalore 560035, India
- Department of Biotechnology, School of Sciences, Jain University, Bangalore 560027, India
| | | | - Gangavarapu Subrahmanyam
- Genomic Division, Seri biotech Research Laboratory, Carmelaram Post, Kodathi, Bangalore 560035, India
| | - Jun Kobayashi
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 1677-1, Yoshida, Yamaguchi 753-8515, Japan
| | - Vankadara Sivaprasad
- Genomic Division, Seri biotech Research Laboratory, Carmelaram Post, Kodathi, Bangalore 560035, India
| | | | - Kangayam M Ponnuvel
- Genomic Division, Seri biotech Research Laboratory, Carmelaram Post, Kodathi, Bangalore 560035, India
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4
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CRISPR/Cas9-Mediated Disruption of the lef8 and lef9 to Inhibit Nucleopolyhedrovirus Replication in Silkworms. Viruses 2022; 14:v14061119. [PMID: 35746591 PMCID: PMC9227026 DOI: 10.3390/v14061119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 02/01/2023] Open
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) is a pathogen that causes severe disease in silkworms. In a previous study, we demonstrated that by using the CRISPR/Cas9 system to disrupt the BmNPV ie-1 and me53 genes, transgenic silkworms showed resistance to BmNPV infection. Here, we used the same strategy to simultaneously target lef8 and lef9, which are essential for BmNPV replication. A PCR assay confirmed that double-stranded breaks were induced in viral DNA at targeted sequences in BmNPV-infected transgenic silkworms that expressed small guide RNAs (sgRNAs) and Cas9. Bioassays and qPCR showed that replication of BmNPV and mortality were significantly reduced in the transgenic silkworms in comparison with the control groups. Microscopy showed degradation of midgut cells in the BmNPV-infected wild type silkworms, but not in the transgenic silkworms. These results demonstrated that transgenic silkworms using the CRISPR/Cas9 system to disrupt BmNPV lef8 and lef9 genes could successfully prevent BmNPV infection. Our research not only provides more alternative targets for the CRISPR antiviral system, but also aims to provide new ideas for the application of virus infection research and the control of insect pests.
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5
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H3K4me3 histone modification in baculovirus-infected silkworm cells. Virus Genes 2021; 57:459-463. [PMID: 34185196 DOI: 10.1007/s11262-021-01858-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/21/2021] [Indexed: 10/21/2022]
Abstract
Baculovirus infection modulates the chromatin states and gene expression of host insect cells. Here we performed chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) of H3 trimethylated at Lys4 (H3K4me3) histone modification in Bombyx mori nucleopolyhedrovirus-infected Bombyx mori cells. The ChIP-seq data revealed the changes of the genome-wide distribution and accumulation of euchromatic histone marks in host insect cells during the progression of baculovirus infection.
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6
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Kokusho R, Katsuma S. Bombyx mori nucleopolyhedrovirus ptp and egt genes are dispensable for triggering enhanced locomotory activity and climbing behavior in Bombyx mandarina larvae. J Invertebr Pathol 2021; 183:107604. [PMID: 33971220 DOI: 10.1016/j.jip.2021.107604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/28/2021] [Accepted: 04/09/2021] [Indexed: 11/18/2022]
Abstract
Baculoviruses are classic pathogens that alter host behavior to enhance their dispersal and transmission. While viral protein tyrosine phosphatase (ptp) has been considered as a critical factor for inducing enhanced locomotory activity, preceding investigations have reported that viral ecdysteroid UDP-glucosyltransferase (egt) contributes to triggering climbing behavior in some virus and host species. Here we found that both egt and ptp were dispensable for these abnormal behaviors in Bombyx mandarina larvae induced by Bombyx mori nucleopolyhedrovirus, thus implying that there is an unknown core mechanism of baculovirus-induced alteration of host behaviors.
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Affiliation(s)
- Ryuhei Kokusho
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
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7
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Kokusho R, Katsuma S. Loss of p24 from the Bombyx mori nucleopolyhedrovirus genome results in the formation of cuboidal occlusion bodies. Virology 2021; 559:173-181. [PMID: 33930820 DOI: 10.1016/j.virol.2021.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/30/2022]
Abstract
Some insect viruses produce the occlusion body (OB), a large crystalline particle comprising a viral protein that occludes virions to protect them from harsh environments. The shapes and sizes of OBs are diverse depending on baculovirus species, but the detailed molecular mechanism determining them has yet to be totally clarified yet. Here we generated Bombyx mori nucleopolyhedrovirus (BmNPV) mutants of the p24 gene that encodes a viral capsid protein and found that p24-mutated BmNPVs produced cuboidal OBs with a slightly larger size than typical truncated octahedral OBs produced by wild-type BmNPVs. Meanwhile, p24 disruption has no significant impact on progeny virus production and viral pathogenicity. In addition, we experimentally demonstrated that a single amino acid substitution found in the P24 protein of the BmNPV Cubic isolate caused cuboidal OB production. These results suggest that p24 has a crucial role in generating the typical shape of OBs.
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Affiliation(s)
- Ryuhei Kokusho
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan; Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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8
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Matsuda–Imai N, Katsuma S. Characterization of Bombyx mori nucleopolyhedrovirus infection in fat body-derived Bombyx mori cultured cells. J Invertebr Pathol 2020; 177:107476. [DOI: 10.1016/j.jip.2020.107476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/19/2020] [Accepted: 09/21/2020] [Indexed: 01/28/2023]
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9
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Bombyx mori nucleopolyhedrovirus Bm96 suppresses viral virulence in Bombyx mori larvae. J Invertebr Pathol 2020; 173:107374. [PMID: 32294464 DOI: 10.1016/j.jip.2020.107374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/04/2020] [Indexed: 11/21/2022]
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) is a severe pathogen for the domestic silkworm, Bombyx mori. BmNPV harbors over 140 protein-coding genes in its 128.4 kilobase pair-long double-stranded genome. However, many BmNPV genes are still uncharacterized. Here we investigated the role of BmNPV Bm96 in both B. mori cultured cells and larvae. We found that Bm96 is mainly expressed at the late stage of infection and accumulation of Bm96 protein peaks at 24 h post infection (hpi) and declines gradually at 48 hpi in B. mori cultured cells. Compared with the wild-type viruses, Bm96-deletion viruses exhibited higher viral propagation and fast-killing phenotype in B. mori larvae. These results strongly suggest that Bm96 negatively regulates the propagation of BmNPV in B. mori larvae. Furthermore, we observed that larvae infected with Bm96-deletion viruses showed lower locomotory activity at the late stage of infection compared with those infected with the wild-type viruses.
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Shen Y, Wang H, Xu W, Wu X. Bombyx mori nucleopolyhedrovirus orf133 and orf134 are involved in the embedding of occlusion-derived viruses into polyhedra. J Gen Virol 2018; 99:717-729. [PMID: 29624165 DOI: 10.1099/jgv.0.001058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) orf133 (bm133) and orf134 (bm134), the orthologues of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac4 and ac5, are two adjacent genes with opposite transcriptional orientations and are highly conserved in all sequenced group I nucleopolyhedroviruses (NPVs). A double bm133-bm134 knockout bacmid was generated to enable the functional study of each gene independently or together. Compared with wild-type and double-repair viruses, deletion of both bm133 and bm134 did not affect budded virus (BV) production or viral DNA replication in transfected BmN cells. Electron microscopy revealed that the double knockout did not affect nucleocapsid assembly, virus-induced intranuclear microvesicle formation or occlusion-derived virus (ODV) production, but the number of virions embedded in the polyhedra decreased significantly. Further investigations showed that disruption of either gene was unable to recover the defect of ODV occlusion, suggesting that Bm133 and Bm134 are indispensable to the embedding of ODVs into polyhedra. Confocal microscopy analysis showed that Bm133 and Bm134 distributed throughout the whole cell during viral infection and Bm134 concentrated on the mature polyhedra in lysed cells. These results suggest that although Bm133 and Bm134 are not essential for BV or ODV development, they play vital roles in polyhedra morphogenesis.
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Affiliation(s)
- Yunwang Shen
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Haiping Wang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Weifan Xu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Xiaofeng Wu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China
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Hikida H, Kokusho R, Kobayashi J, Shimada T, Katsuma S. Inhibitory role of the Bm8 protein in the propagation of Bombyx mori nucleopolyhedrovirus. Virus Res 2018; 249:124-131. [PMID: 29574100 DOI: 10.1016/j.virusres.2018.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/15/2018] [Accepted: 03/19/2018] [Indexed: 11/27/2022]
Abstract
Lepidopteran nucleopolyhedroviruses have distinct viral tissue tropisms in host larvae. We previously identified the Bm8 gene of Bombyx mori nucleopolyhedrovirus (BmNPV), the product of which inhibits viral propagation in the middle silk gland (MSG). However, it is unknown whether this inhibitory function of the Bm8 protein is specific to MSGs. Here we generated a Bm8-disrupted recombinant BmNPV expressing green fluorescent protein (GFP) and examined viral propagation in B. mori cultured cells and larvae. We found that Bm8-disrupted BmNPV produced fewer budded viruses and more occlusion bodies (OBs) than the wild-type virus in both cultured cells and larvae. Microscopic observation of OB production and GFP expression revealed that Bm8 disruption accelerated the progression of viral infection in various larval tissues. Furthermore, quantitative reverse transcription-polymerase chain reaction experiments showed that the loss of Bm8 enhanced viral gene expression in BmNPV-infected larval tissues. These results indicate that the Bm8 protein suppresses viral propagation to varying degrees in each larval tissue, which may establish BmNPV tissue tropisms in B. mori larvae.
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Affiliation(s)
- Hiroyuki Hikida
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Ryuhei Kokusho
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Jun Kobayashi
- Department of Biological and Environmental Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
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Lepetit D, Gillet B, Hughes S, Kraaijeveld K, Varaldi J. Genome Sequencing of the Behavior Manipulating Virus LbFV Reveals a Possible New Virus Family. Genome Biol Evol 2018; 8:3718-3739. [PMID: 28173110 PMCID: PMC5381508 DOI: 10.1093/gbe/evw277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2016] [Indexed: 12/26/2022] Open
Abstract
Parasites are sometimes able to manipulate the behavior of their hosts. However, the molecular cues underlying this phenomenon are poorly documented. We previously reported that the parasitoid wasp Leptopilina boulardi which develops from Drosophila larvae is often infected by an inherited DNA virus. In addition to being maternally transmitted, the virus benefits from horizontal transmission in superparasitized larvae (Drosophila that have been parasitized several times). Interestingly, the virus forces infected females to lay eggs in already parasitized larvae, thus increasing the chance of being horizontally transmitted. In a first step towards the identification of virus genes responsible for the behavioral manipulation, we present here the genome sequence of the virus, called LbFV. The sequencing revealed that its genome contains an homologous repeat sequence (hrs) found in eight regions in the genome. The presence of this hrs may explain the genomic plasticity that we observed for this genome. The genome of LbFV encodes 108 ORFs, most of them having no homologs in public databases. The virus is however related to Hytrosaviridae, although distantly. LbFV may thus represent a member of a new virus family. Several genes of LbFV were captured from eukaryotes, including two anti-apoptotic genes. More surprisingly, we found that LbFV captured from an ancestral wasp a protein with a Jumonji domain. This gene was afterwards duplicated in the virus genome. We hypothesized that this gene may be involved in manipulating the expression of wasp genes, and possibly in manipulating its behavior.
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Affiliation(s)
- David Lepetit
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, France
| | - Benjamin Gillet
- Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Université Lyon 1, Institut de Génomique Fonctionnelle de Lyon UMR 5242, France
| | - Sandrine Hughes
- Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Université Lyon 1, Institut de Génomique Fonctionnelle de Lyon UMR 5242, France
| | - Ken Kraaijeveld
- Department of Ecological Science, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Julien Varaldi
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, France
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Protein composition analysis of polyhedra matrix of Bombyx mori nucleopolyhedrovirus (BmNPV) showed powerful capacity of polyhedra to encapsulate foreign proteins. Sci Rep 2017; 7:8768. [PMID: 28821766 PMCID: PMC5562830 DOI: 10.1038/s41598-017-08987-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/14/2017] [Indexed: 11/23/2022] Open
Abstract
Polyhedra can encapsulate other proteins and have potential applications as protein stabilizers. The extremely stable polyhedra matrix may provide a platform for future engineered micro-crystal devices. However, the protein composition of the polyhedra matrix remains largely unknown. In this study, the occlusion-derived virus (ODV)-removed BmNPV polyhedra matrix fraction was subjected to SDS-PAGE and then an LC-ESI-MS/MS analysis using a Thermo Scientific Q Exactive mass spectrometer. In total, 28 host and 91 viral proteins were identified. The host components were grouped into one of six categories, i.e., chaperones, ubiquitin and related proteins, host helicases, cytoskeleton-related proteins, RNA-binding proteins and others, according to their predicted Pfam domain(s). Most viral proteins may not be essential for polyhedra assembly, as evidenced by studies in the literature showing that polyhedra formation occurs in the nucleus upon the disruption of individual genes. The structural role of these proteins in baculovirus replication will be of significant interest in future studies. The immobilization of enhanced green fluorescent protein (eGFP) into the polyhedra by fusing with the C-terminus of BM134 that is encoded by open reading frame (ORF) 134 suggested that the polyhedra had a powerful capacity to trap foreign proteins, and BM134 was a potential carrier for incorporating proteins of interest into the polyhedra.
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14
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Kokusho R, Koh Y, Fujimoto M, Shimada T, Katsuma S. Bombyx mori nucleopolyhedrovirus BM5 protein regulates progeny virus production and viral gene expression. Virology 2016; 498:240-249. [PMID: 27614700 DOI: 10.1016/j.virol.2016.08.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 08/27/2016] [Accepted: 08/30/2016] [Indexed: 10/21/2022]
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) orf5 (Bm5) is a core gene of lepidopteran baculoviruses and encodes the protein with the conserved amino acid residues (DUF3627) in its C-terminus. Here, we found that Bm5 disruption resulted in lower titers of budded viruses and fewer numbers of occlusion bodies (OBs) in B. mori cultured cells and larvae, although viral genome replication was not affected. Bm5 disruption also caused aberrant expression of various viral genes at the very late stage of infection. Immunocytochemical analysis revealed that BM5 localized to the nuclear membrane. We also found that DUF3627 is important for OB production, transcriptional regulation of viral genes, and subcellular localization of BM5. Compared with wild-type BmNPV infection, larval death was delayed when B. mori larvae were infected with Bm5 mutants. These results suggest that BM5 is involved in progeny virus production and regulation of viral gene expression at the very late stage of infection.
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Affiliation(s)
- Ryuhei Kokusho
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan.
| | - Yoshikazu Koh
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
| | - Masaru Fujimoto
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan.
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Hosamani M, Basagoudanavar SH, Sreenivasa BP, Inumaru S, Ballal CR, Venkataramanan R. Eri silkworm (Samia ricini), a non-mulberry host system for AcMNPV mediated expression of recombinant proteins. J Biotechnol 2015; 216:76-81. [PMID: 26467714 DOI: 10.1016/j.jbiotec.2015.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/25/2015] [Accepted: 10/06/2015] [Indexed: 10/22/2022]
Abstract
The baculovirus expression system (BVES) based on Autographa californica nucleopolyhedrovirus (AcMNPV) is widely used for the expression of eukaryotic proteins. Several insect cells/larvae that are permissive to AcMNPV have been routinely used as hosts to express heterologous proteins. Domesticated Eri silkworm (Samia ricini), reared in many parts of India, Japan and China, is a non-mulberry silkworm. The present study shows that the Eri silkworm larvae are susceptible to intra-haemocoelical inoculation of AcMNPV. The virus replicates in the larva, as indicated by an increased viral loads in the haemolymph upon injection of a recombinant AcMNPV carrying green fluorescent protein gene. The virus showed localized replication in different tissues including the fat body, haemocytes, tracheal matrix and in the Malphigian tubules. The larval system was successfully used to express heterologous protein, by infecting with a recombinant AcMNPV carrying the 3ABC coding sequence of foot-and-mouth disease virus (FMDV). The study shows that the Eri silkworm larva can be a potential alternative bioreactor, for scaling up of the recombinant proteins employing the baculovirus system.
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Affiliation(s)
- Madhusudan Hosamani
- ICAR - Indian Veterinary Research Institute, Hebbal, Bengaluru 560024, India.
| | | | - B P Sreenivasa
- ICAR - Indian Veterinary Research Institute, Hebbal, Bengaluru 560024, India
| | - Shigeki Inumaru
- National Institute of Animal Health, 3-1-5 Kan-non-dai, Tsukuba, Ibaraki 305-0856, Japan
| | - Chandish R Ballal
- ICAR-National Bureau of Agricultural Insect Resources, Hebbal, Bengaluru 560024, India
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Baculovirus protein PK2 subverts eIF2α kinase function by mimicry of its kinase domain C-lobe. Proc Natl Acad Sci U S A 2015. [PMID: 26216977 DOI: 10.1073/pnas.1505481112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) by eIF2α family kinases is a conserved mechanism to limit protein synthesis under specific stress conditions. The baculovirus-encoded protein PK2 inhibits eIF2α family kinases in vivo, thereby increasing viral fitness. However, the precise mechanism by which PK2 inhibits eIF2α kinase function remains an enigma. Here, we probed the mechanism by which PK2 inhibits the model eIF2α kinase human RNA-dependent protein kinase (PKR) as well as native insect eIF2α kinases. Although PK2 structurally mimics the C-lobe of a protein kinase domain and possesses the required docking infrastructure to bind eIF2α, we show that PK2 directly binds the kinase domain of PKR (PKR(KD)) but not eIF2α. The PKR(KD)-PK2 interaction requires a 22-residue N-terminal extension preceding the globular PK2 body that we term the "eIF2α kinase C-lobe mimic" (EKCM) domain. The functional insufficiency of the N-terminal extension of PK2 implicates a role for the adjacent EKCM domain in binding and inhibiting PKR. Using a genetic screen in yeast, we isolated PK2-activating mutations that cluster to a surface of the EKCM domain that in bona fide protein kinases forms the catalytic cleft through sandwiching interactions with a kinase N-lobe. Interaction assays revealed that PK2 associates with the N- but not the C-lobe of PKR(KD). We propose an inhibitory model whereby PK2 engages the N-lobe of an eIF2α kinase domain to create a nonfunctional pseudokinase domain complex, possibly through a lobe-swapping mechanism. Finally, we show that PK2 enhances baculovirus fitness in insect hosts by targeting the endogenous insect heme-regulated inhibitor (HRI)-like eIF2α kinase.
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Kokusho R, Kawamoto M, Koyano Y, Sugano S, Suzuki Y, Shimada T, Katsuma S. Bombyx mori nucleopolyhedrovirus actin rearrangement-inducing factor 1 enhances systemic infection in B. mori larvae. J Gen Virol 2015; 96:1938-46. [PMID: 25809914 DOI: 10.1099/vir.0.000130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The actin rearrangement-inducing factor 1 (arif-1) gene is a baculoviral early gene conserved in most alphabaculoviruses. Previous studies reported that Autographa californica nucleopolyhedrovirus ARIF-1 protein induces filamentous actin concentration on the plasma membrane during the early stage of infection in Trichoplusia ni TN-368 cells, but its role in larval infection remains unknown. In this study, we performed behavioural screening using Bombyx mori larvae infected with Bombyx mori nucleopolyhedrovirus (BmNPV) mutants and found that larvae infected with arif-1-mutated BmNPVs did not show locomotor hyperactivity that was normally observed in BmNPV-infected larvae. arif-1-deficient BmNPVs also showed reduced pathogenicity and total viral propagation in B. mori larvae, whereas viral propagation of arif-1-deficient viruses was comparable with that of control viruses in B. mori cultured cells. An arif-1-defective BmNPV expressing the GFP gene (gfp) was used to monitor the progression of infection in B. mori larvae. GFP expression and quantitative reverse transcription-PCR analyses revealed that infection by the arif-1-disrupted virus was significantly delayed in trachea, fat body, suboesophageal ganglion and brain. These results indicated that BmNPV ARIF-1 enhanced systemic infection in B. mori larvae.
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Affiliation(s)
- Ryuhei Kokusho
- 1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Munetaka Kawamoto
- 1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yasue Koyano
- 1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Sumio Sugano
- 2Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Yutaka Suzuki
- 3Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Toru Shimada
- 1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Susumu Katsuma
- 1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Katsuma S, Shimada T. The killing speed of egt-inactivated Bombyx mori nucleopolyhedrovirus depends on the developmental stage of B. mori larvae. J Invertebr Pathol 2015; 126:64-70. [PMID: 25681781 DOI: 10.1016/j.jip.2015.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 01/23/2015] [Accepted: 01/24/2015] [Indexed: 11/26/2022]
Abstract
Several lines of evidence have shown that the deletion of the ecdysteroid UDP-glucosyltransferase gene (egt) from the nucleopolyhedrovirus (NPV) genome increases the killing speed of host lepidopteran larvae. However, it has not been investigated in detail whether the effects of egt deletion depend on the larval stages of the host insect. In this study, we performed bioassays using 10 continuous larval stages of the 4th- or 5th-instar Bombyx mori larvae and B. mori NPV egt mutants. The fast-killing phenotype was observed in the egt mutants only when the infection process progressed through larval-larval transition. All day-2 4th-instar larvae infected with the egt mutants entered the molting stage and died much earlier than wild-type-infected larvae. Bodies of egt mutant-infected larvae were filled with excessive fluid immediately after head capsule slippage, owing presumably to the degeneration of Malpighian tubules. Fourth- or 5th-instar larvae infected with the egt mutants at early stages of each instar died similarly to those infected with the wild-type virus. Under infection in the middle stages of the 5th-instar, the survival time of egt mutant-infected larvae was significantly longer than that of the wild-type virus-infected larvae. These results clearly show that the effects of egt deletion on killing speed of NPV are largely dependent on the developmental stage of the host larvae infected by the virus.
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Affiliation(s)
- Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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The Ac124 protein is not essential for the propagation of Autographa californica multiple nucleopolyhedrovirus, but it is a viral pathogenicity factor. Arch Virol 2014; 160:275-84. [DOI: 10.1007/s00705-014-2277-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 10/30/2014] [Indexed: 12/25/2022]
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Zhang J, Chen XM, Zhang CD, He Q, Dong ZQ, Cao MY, Dong XL, Pan CX, Lu C, Pan MH. Differential susceptibilities to BmNPV infection of two cell lines derived from the same silkworm ovarian tissues. PLoS One 2014; 9:e105986. [PMID: 25221982 PMCID: PMC4164443 DOI: 10.1371/journal.pone.0105986] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 07/30/2014] [Indexed: 11/18/2022] Open
Abstract
We previously established and characterized two insect cell lines (BmN-SWU1 and BmN-SWU2) from Bombyx mori ovaries. Here, we examined their differential susceptibilities to Bombyx mori nucleopolyhedrovirus (BmNPV) despite having originated from the same tissue source. BmN-SWU1 cells were susceptible and supported high titers of BmNPV replication, while BmN-SWU2 cells were resistant to BmNPV infection. Subcellular localization analysis demonstrated that very few BmNPV particles could be imported into BmN-SWU2 cells. However, initiation of BmNPV DNA replication but not amplification was detected in BmN-SWU2 cells after transfection with vA4prm-VP39-EGFP bacmid DNA. BmNPV transcription assays showed that late and very late but not early viral genes apparently were blocked in BmNSWU2 cells by unknown mechanisms. Further syncytium formation assays demonstrated that the BmNPV envelope fusion protein GP64 could not mediate BmN-SWU2 host cell-cell membrane fusion. Taken together, these results indicate that these two cell lines represent optimal tools for investigating host-virus interactions and insect antiviral mechanisms.
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Affiliation(s)
- Jun Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China; Institute of Life Sciences, Chongqing Medical University, Chongqing, China
| | - Xue-Mei Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Chun-Dong Zhang
- Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing, China
| | - Qian He
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Zhan-Qi Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Ming-Ya Cao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Xiao-Long Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Cai-Xia Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Min-Hui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
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Yang M, Huang C, Qian DD, Li LL. Functional characterization of Autographa californica multiple nucleopolyhedrovirus gp16 ( ac130 ). Virology 2014; 464-465:341-352. [DOI: 10.1016/j.virol.2014.07.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 05/07/2014] [Accepted: 07/18/2014] [Indexed: 10/24/2022]
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Singh CP, Vaishna RL, Kakkar A, Arunkumar KP, Nagaraju J. Characterization of antiviral and antibacterial activity ofBombyx moriseroin proteins. Cell Microbiol 2014; 16:1354-65. [DOI: 10.1111/cmi.12294] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/24/2014] [Accepted: 03/07/2014] [Indexed: 12/30/2022]
Affiliation(s)
- C. P. Singh
- Centre of Excellence for Genetics and Genomics of Silkmoths; Laboratory of Molecular Genetics; Centre for DNA Fingerprinting and Diagnostics; Tuljaguda Complex Nampally Hyderabad 500001 India
| | - R. L. Vaishna
- Centre of Excellence for Genetics and Genomics of Silkmoths; Laboratory of Molecular Genetics; Centre for DNA Fingerprinting and Diagnostics; Tuljaguda Complex Nampally Hyderabad 500001 India
| | - A. Kakkar
- Centre of Excellence for Genetics and Genomics of Silkmoths; Laboratory of Molecular Genetics; Centre for DNA Fingerprinting and Diagnostics; Tuljaguda Complex Nampally Hyderabad 500001 India
| | - K. P. Arunkumar
- Centre of Excellence for Genetics and Genomics of Silkmoths; Laboratory of Molecular Genetics; Centre for DNA Fingerprinting and Diagnostics; Tuljaguda Complex Nampally Hyderabad 500001 India
| | - J. Nagaraju
- Centre of Excellence for Genetics and Genomics of Silkmoths; Laboratory of Molecular Genetics; Centre for DNA Fingerprinting and Diagnostics; Tuljaguda Complex Nampally Hyderabad 500001 India
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Chen L, Yang R, Hu XL, Xiang XW, Wu XF. Expression analysis of chlorophyllid α binding protein, a secretory, red fluorescence protein in the midgut of silkworm, Bombyx mori. INSECT SCIENCE 2014; 21:20-30. [PMID: 23956194 DOI: 10.1111/1744-7917.12026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 06/02/2023]
Abstract
Chlorophyllid α binding protein (chbp) was recently characterized by its ability to bind the prosthetic group of chlorophylls and little information is known regarding its expression. In the present study, we found that chpb was expressed highly and exclusively in the midgut of silkworm, Bombyx mori. The expression level of chbp was very high in the newly molted fifth instar larvae followed by gradual decline in the same instar. Our results demonstrated that CHBP was a secretory protein and located mainly in the apical of midgut epithelial cells. Real-time polymerase chain reaction analysis results showed that chpb highly expressed in the anterior midgut, threefold and sixfold higher compared with that of the middle midgut and posterior midgut, respectively, and chpb expression declined in darkness. In addition, the expression of chbp was affected by high-dose virus or bacterium infection.
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Affiliation(s)
- Lin Chen
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, China
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Ishihara G, Shimada T, Katsuma S. Functional characterization of Bombyx mori nucleopolyhedrovirus CG30 protein. Virus Res 2013; 174:52-9. [PMID: 23507307 DOI: 10.1016/j.virusres.2013.02.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 02/25/2013] [Accepted: 02/25/2013] [Indexed: 11/30/2022]
Abstract
The baculovirus cg30 gene is present in the genomes of most alphabaculoviruses. The gene product, CG30, contains two putative functional domains, a RING finger motif and a leucine zipper motif. A gene-knockout study in Autographa californica nucleopolyhedrovirus (AcMNPV) revealed that a cg30-disrupted virus did not show any striking differences compared with wild-type virus. To determine the roles of cg30 in another alphabaculovirus, we constructed two Bombyx mori NPV (BmNPV) mutants lacking a functional cg30 by lacZ cassette insertion and characterized its infectivity in BmN cells and B. mori larvae. The mutants produced fewer budded viruses (BVs) in BmN cells and B. mori larvae compared with wild-type BmNPV. We also observed a decrease in the release of occlusion bodies (OBs) in the hemolymph of the larvae infected with the cg30 mutants. To investigate the role of a RING finger domain of CG30 during virus growth, we further constructed two mutants; one expressed a mutant CG30 where a RING finger motif is disrupted by a single amino acid substitution, whereas the other possessed a CG30 derivative that completely lacked the RING finger domain. Both produced fewer OBs in the hemolymph of B. mori larvae, demonstrating that a RING finger domain of CG30 is involved in maximum OB production in the hemolymph of B. mori larvae. We also revealed that CG30 is expressed as a nuclear protein with a molecular mass of 30kDa in BmNPV-infected cells.
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Affiliation(s)
- Genki Ishihara
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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