The Experts below are selected from a list of 1569 Experts worldwide ranked by ideXlab platform

Chuan-xi Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Genomic diversity of Bombyx Mori Nucleopolyhedrovirus strains
    Genomics, 2013
    Co-Authors: Xu Yipeng, Ruo-lin Cheng, Chuan-xi Zhang
    Abstract:

    Bombyx Mori Nucleopolyhedrovirus (BmNPV) is a baculovirus that selectively infects the domestic silkworm. In this study, six BmNPV strains were compared at the whole genome level. We found that the number of bro genes and the composition of the homologous regions (hrs) are the two primary areas of divergence within these genomes. When we compared the ORFs of these BmNPV variants, we noticed a high degree of sequence divergence in the ORFs that are not baculovirus core genes. This result is consistent with the results derived from phylogenetic trees and evolutionary pressure analyses of these ORFs, indicating that ORFs that are not core genes likely play important roles in the evolution of BmNPV strains. The evolutionary relationships of these BmNPV strains might be explained by their geographic origins or those of their hosts. In addition, the total number of hr palindromes seems to affect viral DNA replication in Bm5 cells.

  • Genome of a Bombyx Mori Nucleopolyhedrovirus Strain Isolated from India
    Journal of virology, 2012
    Co-Authors: Hai-wei Fan, Xiaowen Cheng, Xu Yipeng, Xue-chao Zhang, Chuan-xi Zhang
    Abstract:

    Bombyx Mori Nucleopolyhedrovirus (BmNPV), a member of the Baculoviridae, is a major pathogen of silkworm and has also been recently developed as an expression vector for heterologous gene expression in the silkworm larvae and pupae. To better understand the diversity of this important baculovirus, we sequenced the complete genome of the BmNPV strain isolated from India, where its host is available throughout the year due to its tropical climate. The genome of the Indian strain consists of 127,879 nucleotides, with a G+C content of 40.36%. There are 138 open reading frames (ORFs) encoding the predicted proteins of more than 50 amino acids. Genomic comparison of the Indian strain with 3 other reported BmNPV strains showed that the baculovirus repeat ORFs (bro) and homologous repeat regions (hr's) are highly variable. These results suggest that the BmNPV strain heterogeneity is mainly caused by single-nucleotide polymorphisms (SNPs) and changes in the hr's and bro genes.

  • Genome Sequence of a Bombyx Mori Nucleopolyhedrovirus Strain with Cubic Occlusion Bodies
    Journal of virology, 2012
    Co-Authors: Ruo-lin Cheng, Xu Yipeng, Chuan-xi Zhang
    Abstract:

    ABSTRACT Bombyx Mori Nucleopolyhedrovirus (BmNPV) is a typical species of Baculoviridae. The complete genome sequence of a BmNPV strain with cubic occlusion bodies is reported here. The genome of this strain consists of 127,465 nucleotides with a G+C content of 40.36% and is 97.3% and 97.5% identical to those of BmNPV strain T3 and Bombyx mandarina NPV S1, respectively. Despite the abnormal polyhedra it forms, the polyhedrin gene of the BmNPV cubic strain is 100% identical to those of the other two strains. Baculovirus repeated ORFs and homologous repeat regions cause the major differences in genome size of these BmNPV isolates.

  • Bombyx Mori Nucleopolyhedrovirus ORF54, a viral desmoplakin gene, is associated with the infectivity of budded virions.
    Archives of virology, 2012
    Co-Authors: Min-juan Zhang, Cai-hong Tian, Ruo-lin Cheng, Xiao-ying Fan, Yi-han Lou, Chuan-xi Zhang
    Abstract:

    Bombyx Mori Nucleopolyhedrovirus (BmNPV) ORF54 (Bm54), a member of the viral desmoplakin N-terminus superfamily, is homologous to Autographa californica Nucleopolyhedrovirus (AcMNPV) ORF66, which is required for the efficient egress of nucleocapsids from the nucleus and occlusion body formation. In this paper, we generated a bacmid with the Bm54 gene deleted via homologous recombination in Escherichia coli and characterized the mutant virus using a transfection-infection assay and transmission electron microscopy analysis. Our results demonstrated that the cells transfected with viral DNA lacking Bm54 produced non-infectious budded viruses (BVs). Electron microscopy showed that although the deletion of Bm54 did not affect assembly and release of nucleocapsids, it severely affected polyhedron formation. In conclusion, deletion of Bm54 resulted in non-infectious BV and defective polyhedra. Although the sequences of Bm54 and Ac66 are very similar, the two genes function quite differently in the regulation of viral life cycle.

  • Characterization of a late gene, ORF75 from Bombyx Mori Nucleopolyhedrovirus.
    Molecular biology reports, 2010
    Co-Authors: Guo-hui Gao, Xu Yipeng, Chuan-xi Zhang
    Abstract:

    Open reading frame 75 (Bm-p33) of Bombyx Mori Nucleopolyhedrovirus (BmNPV) is a homologue of Autographa californica multiple Nucleopolyhedrovirus ORF92. The gene is conserved among all baculoviruses that have been completely sequenced to date and is considered to be a baculovirus core set gene. No amino acid mutation was found in Bm-p33 sequences among six BmNPV strains differing in geography, phenotype, or host. The Bm-p33 transcript can be detected as early as 12 h post infection (h p.i.) and remains detectable until 96 h p.i. The Bm-p33 protein was detected in cell lysates from 18 h p.i. through 96 h p.i., and no positive band could be detected in budded viruses (BVs) and occlusion-derived viruses (ODVs) by western blot using anti-Bm-p33 serum. Immunofluorescence microscopy indicated that Bm-p33 accumulated in the nuclear membrane and the intranuclear region, especially near the nuclear membrane of the virus-infected cells. Bm75 RNAi significantly decreased the mRNA level. However, no obvious effects on ODV formation and BV production in BmNPV-infected cells could be detected. Bm-p33 is a BmNPV late gene encoding a nonstructural protein which may function mainly in the nucleus of the infected cells.

Susumu Katsuma - One of the best experts on this subject based on the ideXlab platform.

  • Bombyx Mori Nucleopolyhedrovirus Bm96 suppresses viral virulence in Bombyx Mori larvae.
    Journal of invertebrate pathology, 2020
    Co-Authors: Hiroyuki Hikida, Ryuhei Kokusho, Noriko Matsuda-imai, Susumu Katsuma
    Abstract:

    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.

  • Whole-genome sequencing and comparative transcriptome analysis of Bombyx Mori Nucleopolyhedrovirus La strain
    Virus Genes, 2020
    Co-Authors: Shota Fujimoto, Susumu Katsuma, Munetaka Kawamoto, Keisuke Shoji, Yutaka Suzuki, Masashi Iwanaga
    Abstract:

    The Bombyx Mori Nucleopolyhedrovirus (BmNPV) La is a variant BmNPV strain isolated in Laos. La has different features from BmNPV type strain T3 in virulence, production of the polyhedrin protein, and the formation of multicapsid occlusion-derived viruses. Here, the whole-genome sequence of La was compared to the sequences of nine BmNPV and two Bombyx mandarina Nucleopolyhedrovirus strains. The complete La genome consisted of 127,618 base pairs with a G + C content of 40.3% and contained putative 136 open reading frames encoding more than 60 amino acids. The La genome lacked the bro-b gene and had the highest identity with that of the T3 strain. A comparison of the transcriptomes of La- and T3-infected cells showed that the expression levels of the polyhedrin and cathepsin genes were greater in cells infected with La as compared to those infected with T3. Interestingly, the virus genes with different RNA levels between the two BmNPV strains were assembled into five clusters in the genome of La. Also, the RNA levels of host ribosomal protein genes were significantly decreased in cells infected with La as compared to those infected with T3.

  • Infectious Virions of Bombyx Mori Latent Virus Are Incorporated into Bombyx Mori Nucleopolyhedrovirus Occlusion Bodies.
    Viruses, 2019
    Co-Authors: Keita Tsukui, Chihiro Yagisawa, Shota Fujimoto, Moe Ogawa, Ryuhei Kokusho, Mitsuyoshi Nozawa, Hideki Kawasaki, Susumu Katsuma, Masashi Iwanaga
    Abstract:

    The Bombyx Mori latent virus (BmLV) belongs to the unassigned plant virus family Tymoviridae and contains a positive-sense, single-stranded RNA genome. BmLV has infected almost all B. Mori-derived cultured cell lines through unknown routes. The source of BmLV infection and the BmLV life cycle are still unknown. Here, we examined the interaction between BmLV and the insect DNA virus Bombyx Mori Nucleopolyhedrovirus (BmNPV). Persistent infection with BmLV caused a slight delay in BmNPV propagation, and BmLV propagation was enhanced in B. Mori larvae via co-infection with BmNPV. We also showed that BmLV infectious virions were co-occluded with BmNPV virions into BmNPV occlusion bodies. We propose a new relationship between BmLV and BmNPV.

  • Inhibitory role of the Bm8 protein in the propagation of Bombyx Mori Nucleopolyhedrovirus
    Virus research, 2018
    Co-Authors: Hiroyuki Hikida, Ryuhei Kokusho, Toru Shimada, Jun Kobayashi, Susumu Katsuma
    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.

  • Bombyx Mori Nucleopolyhedrovirus BM5 protein regulates progeny virus production and viral gene expression.
    Virology, 2016
    Co-Authors: Ryuhei Kokusho, Toru Shimada, Yoshikazu Koh, Masaru Fujimoto, Susumu Katsuma
    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.

Toru Shimada - One of the best experts on this subject based on the ideXlab platform.

  • Inhibitory role of the Bm8 protein in the propagation of Bombyx Mori Nucleopolyhedrovirus
    Virus research, 2018
    Co-Authors: Hiroyuki Hikida, Ryuhei Kokusho, Toru Shimada, Jun Kobayashi, Susumu Katsuma
    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.

  • Bombyx Mori Nucleopolyhedrovirus BM5 protein regulates progeny virus production and viral gene expression.
    Virology, 2016
    Co-Authors: Ryuhei Kokusho, Toru Shimada, Yoshikazu Koh, Masaru Fujimoto, Susumu Katsuma
    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.

  • Bombyx Mori Nucleopolyhedrovirus actin rearrangement inducing factor 1 enhances systemic infection in b Mori larvae
    Journal of General Virology, 2015
    Co-Authors: Ryuhei Kokusho, Toru Shimada, Munetaka Kawamoto, Yutaka Suzuki, Yasue Koyano, Sumio Sugano, Susumu Katsuma
    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.

  • Silkworm plasmatocytes are more resistant than other hemocyte morphotypes to Bombyx Mori Nucleopolyhedrovirus infection.
    Journal of invertebrate pathology, 2012
    Co-Authors: Takanori Hori, Takashi Kiuchi, Toru Shimada, Masao Nagata, Susumu Katsuma
    Abstract:

    Differences in the viral susceptibility of multiple insect hemocyte morphotypes have not been investigated to date. In this study, a Bombyx Mori Nucleopolyhedrovirus (BmNPV) derivative possessing a Drosophila hsp70 promoter-driven green fluorescent protein (GFP) gene was used to observe NPV tropism of B. Mori larval hemocytes. The experiments clearly revealed that there were fewer GFP-positive plasmatocytes than those observed in other types of hemocytes, such as granulocytes, oenocytoids, and spherulocytes, when infected via the intrahemocoelic or oral route. Our results indicate that silkworm plasmatocytes are more resistant than other hemocyte morphotypes to BmNPV infection.

  • Identification and characterization of host factors interacting with Bombyx Mori Nucleopolyhedrovirus ORF8
    Journal of Microbiology, 2012
    Co-Authors: Wonkyung Kang, Susumu Katsuma, Noriko Matsuda-imai, Toru Shimada, Masaaki Kurihara, Toyoshi Yoshiga, Shogo Matsumoto
    Abstract:

    The orf8 gene ( Bm8 ) in Bombyx Mori Nucleopolyhedrovirus (BmNPV) is one of 17 genes unique to group I NPVs and is expressed as an early gene. We have reported that Bm8 may play an important role during viral infection and that Bm8 protein co-localized with IE1 to specific nuclear foci throughout infection. It was also demonstrated that both IE1 and BmNPV hr facilitate this localization of Bm8. To investigate further, host proteins interacting with Bm8 were screened using a yeast two-hybrid system. We identified 6 host clones as Bm8-interacting partners from three cDNA libraries derived from BmN cells or B. Mori larvae. Further assays showed that the N-terminal region of Bm8 is important for the interaction with most host clones and that two of the clones can associate with IE1. Cloning and sequencing of full-length cDNAs revealed that most of the clones potentially encode either membrane-bound proteins or secreted proteins. Quantitative RT-PCR analysis revealed that some of these host genes were slightly induced during the early stage of infection in BmN cells, and that the expression of all genes was markedly reduced during the late stage of infection. Generation of mutant BmNPVs over-expressing these host genes also identified a gene that potentially functions as a negative factor during BmNPV infection. These features of Bm8-interacting host proteins strongly support that Bm8 is a multifunctional protein involved in multiple signaling pathways in host cells.

Keping Chen - One of the best experts on this subject based on the ideXlab platform.

  • Bombyx Mori Nucleopolyhedrovirus ORF101 encodes a budded virus envelope associated protein.
    Current microbiology, 2014
    Co-Authors: Huiqing Chen, Keping Chen, Guoping Huang, Weijun Mai, Yajing Zhou
    Abstract:

    Orf101 (Bm101) of Bombyx Mori Nucleopolyhedrovirus (BmNPV) is a highly conserved gene in lepidopteran Nucleopolyhedroviruses, but its function remains unknown. In this study, Bm101 was characterized. Transcripts of Bm101 were detected from 24 through 96 h post infection (h p.i.) by RT-PCR. The corresponding protein was also detected from 24 to 96 h p.i. in BmNPV-infected BmN cells by Western blot analysis using a polyclonal antibody against Bm101. Western blot assay of occlusion-derived virus and budded virus (BV) preparations revealed that Bm101 encodes a 28-kDa structural protein that is associated with BV and is located in the envelope fraction of budded virions. In addition, confocal analysis showed that the protein was localized in the cytosol and cytoplasmic membrane in virus-infected cells. In conclusion, the available data suggest that Bm101 is a functional ORF of BmNPV and encodes a protein expressed in the late stage of the infection cycle that is associated with the BV envelope.

  • The Bombyx Mori Nucleopolyhedrovirus Bm111 Affects Virulence but not Virus Replication
    Current microbiology, 2014
    Co-Authors: Yingying Han, Qi Tang, Hengchuan Xia, Yanhua Yang, Dandan Shao, Keping Chen
    Abstract:

    The Bm111 of Bombyx Mori Nucleopolyhedrovirus (BmNPV) encodes a small polypeptide (70 amino acids) of which the function remains unknown. To characterize its function, multiple sequence alignments were performed, and the predicted protein was found to share amazingly high (98 %) sequence identity with the Bombyx mandarina Nucleopolyhedrovirus ORF110 (Boma110) but negligible with proteins of other insect viruses, indicating the close relationship between these two NPVs with silkworm larvae. The transcription of Bm111 was detected as early as 3 hpi in BmNPV-infected BmN cells, suggesting it is an early gene. To investigate the role of Bm111 in baculovirus life cycle, a Bm111-knockout virus was constructed by bacmid recombination in Escherichia coli. The results showed that knockout of the Bm111 did not affect the replication of virus DNA, but significantly extended the death time of infected silkworm larvae compared to the wild-type or rescued viruses. We also successfully expressed the recombinant protein Bm111 in E. coli to provide sufficient material for subsequent studies. Taken together, our data indicate that Bm111 only affects the virulence of BmNPV, but not its replication.

  • Expression, purification, and enzymatic characterization of Bombyx Mori Nucleopolyhedrovirus DNA polymerase.
    Archives of virology, 2013
    Co-Authors: Liu Liu, Keping Chen, Huiqing Chen, Huifang Song, Zhang Lei, Fan Xiaoting, Zhang Qian, Yajing Zhou
    Abstract:

    Bombyx Mori Nucleopolyhedrovirus (BmNPV) is a major viral agent that causes deadly grasserie disease in silkworms. BmNPV DNA polymerase (Bm-DNAPOL), encoded by the ORF53 gene, plays a central role in viral DNA replication. In this work, a His-tagged Bm-DNAPOL fusion protein, constructed using a novel MultiBac expression system, was overexpressed in Sf-9 insect cells, purified to near homogeneity on Ni-NTA agarose beads and further purified by ion-exchange chromatography. About 0.4 mg of enzyme was obtained from about 1 × 109 infected Sf-9 cells in suspension culture. Characterization of the highly purified enzyme indicated that Bm-DNAPOL is a monomer with an apparent molecular mass of approximately 110,000 Da. It possessed a specific activity of 15,126.3 U/mg under optimal in vitro reaction conditions and behaved in the manner of a proliferating cell nuclear antigen (PCNA)-independent DNA polymerase on both poly(dA)/oligo(dT) primer/template and singly premiered M13 DNA. BmNPV viral replication may be independent of replication factor C and a PCNA complex, while single-stranded DNA binding protein might play an important role in BmNPV DNA replication. These findings will be significant in studies on BmNPV-based disease in silkworms and for using silkworms as a bioreactor for the production of biomolecules of commercial importance.

  • Expression and functional validation of Bombyx Mori Nucleopolyhedrovirus ORF29, a conserved Nudix motif protein.
    Acta virologica, 2013
    Co-Authors: Huiqing Chen, Yajing Zhou, Keping Chen
    Abstract:

    Our previous study showed that Bombyx Mori Nucleopolyhedrovirus (BmNPV) orf29 encodes a 26 kDa protein expressed in the early stage of infection cycle. BmNPV ORF29, contains a conserved motif of Nudix (nucleotide diphosphate X) superfamily. It has the highest homology with ADP-ribose pyrophosphatase (ADPRase), a subfamily of Nudix pyrophosphatase. In this work, we purified the recombinant BmNPV ORF29 in Escherichia coli by metal chelating affinity chromatography. The amino acid sequence of recombinant protein was confirmed by mass spectroscopic analysis and found that the purified protein could be able to catalyze the breakdown of ADP-ribose to AMP and ribose 5-phosphate, with Km and Kcat values of 182 μmol/l and 5.3 s-1 respectively. The optimal activity was at alkaline pH (8.5) with Mg2+ (0.5-mmol/l) ions as the cofactor.

  • Bm65 is essential for the propagation of Bombyx Mori Nucleopolyhedrovirus.
    Current microbiology, 2012
    Co-Authors: Qi Tang, Qin Yao, Liang Chen, Fan Feng, Yi Yuan, Keping Chen
    Abstract:

    Orf65 (Bm65) of Bombyx Mori Nucleopolyhedrovirus (BmNPV) is a highly conserved gene that encodes an unknown 104-amino acid protein. In the present study, we have shown the role of Bm65 in the baculovirus life cycle. 5'-RACE analysis showed that the transcription start site of Bm65 was 14 nucleotides upstream of the start codon ATG. The transcription profile of Bm65 was detected from 6 to 72 h postinfection (p. i.) by RT-PCR. A Bm65-knockout bacmid was constructed by homologous recombination to characterize the role of Bm65 in viral life cycle. Fluorescence microscopy showed that Bm65-knockout virus was unable to generate infectious budded virus in BmN cells. Furthermore, quantitative real-time PCR analysis demonstrated that Bm65 deletion did not affect the viral DNA replication. To conclude, Bm65 is essential for the propagation of BmNPV, but is unnecessary for the replication of viral DNA.

Zhong-jian Guo - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of aggregate/aggresome structures formed by polyhedrin of Bombyx Mori Nucleopolyhedrovirus.
    Scientific Reports, 2015
    Co-Authors: Zhong-jian Guo, Liu-xing Tao, Xian-yun Dong, Ting Tian, Xu-dong Tang
    Abstract:

    Virus infections often lead to formation of aggregates and aggresomes in host cells. In this study, production of aggregates and aggresomes by the highly expressed protein polyhedrin of Bombyx Mori Nucleopolyhedrovirus (BmNPV) at 24 h postinfection (p.i.) was detected with a fluorescent molecular dye, and verified by colocalization of polyhedrin with aggresomal markers, GFP-250 and γ-tubulin. Polyhedrin aggregates showed hallmark characteristics of aggresomes: formation was microtubule-dependent; they colocalized with heat shock cognates/proteins of the 70-kDa family (HSC/HSP70s), ubiquitinated proteins and recruited the mitochondria. Aggregated polyhedrin protein gradually gained its active conformation accompanying progress of BmNPV infection. At 48 h p.i. recovered polyhedrin bound directly to Bombyx Mori microtubule-associated protein 1-light chain 3 (BmLC3), an autophagosome marker, and was colocalized with BmLC3 to the isolation membrane of autophagosome, implying the involvement of polyhedrin in cellular autophagy. Inhibition of autophagy by 3-methyladenine (3-MA) dramatically resulted in decrease of polyhedrin expression and polyhedra particle production. These observations suggested that highly expressed polyhedrin forms aggregate to get involved in cellular autophagy then play an important role in polyhedra production.

  • characterization of aggregate aggresome structures formed by polyhedrin of Bombyx Mori Nucleopolyhedrovirus
    Scientific Reports, 2015
    Co-Authors: Zhong-jian Guo, Liu-xing Tao, Xian-yun Dong, Ting Tian, Xu-dong Tang
    Abstract:

    Virus infections often lead to formation of aggregates and aggresomes in host cells. In this study, production of aggregates and aggresomes by the highly expressed protein polyhedrin of Bombyx Mori Nucleopolyhedrovirus (BmNPV) at 24 h postinfection (p.i.) was detected with a fluorescent molecular dye, and verified by colocalization of polyhedrin with aggresomal markers, GFP-250 and γ-tubulin. Polyhedrin aggregates showed hallmark characteristics of aggresomes: formation was microtubule-dependent; they colocalized with heat shock cognates/proteins of the 70-kDa family (HSC/HSP70s), ubiquitinated proteins and recruited the mitochondria. Aggregated polyhedrin protein gradually gained its active conformation accompanying progress of BmNPV infection. At 48 h p.i. recovered polyhedrin bound directly to Bombyx Mori microtubule-associated protein 1-light chain 3 (BmLC3), an autophagosome marker, and was colocalized with BmLC3 to the isolation membrane of autophagosome, implying the involvement of polyhedrin in cellular autophagy. Inhibition of autophagy by 3-methyladenine (3-MA) dramatically resulted in decrease of polyhedrin expression and polyhedra particle production. These observations suggested that highly expressed polyhedrin forms aggregate to get involved in cellular autophagy then play an important role in polyhedra production.

  • Characterization of Bombyx Mori Nucleopolyhedrovirus with a knockout of Bm17
    Cytotechnology, 2012
    Co-Authors: Hongxing Shen, Zhong-jian Guo, Wen Zhang, Bin Nin, Yang Zhou, Shihe Shao, Huiqing Chen, Hua Wang, Xiaochun Wang, Xiaoyong Liu
    Abstract:

    Open reading frame 17 (Bm17) gene of Bombyx Mori Nucleopolyhedrovirus is a highly conserved gene in lepidopteran Nucleopolyhedroviruses, but its function remains unknown. In this report, transient-expression and superinfection assays indicated that BM17 localized in the nucleus and cytoplasm of infected BmN cells. To determine the role of Bm17 in baculovirus life cycle, we constructed a Bm17 knockout virus and characterized its properties in cells. Analysis of the production and infection of budded virions, the level of viral DNA replication revealed showed that there was no significant difference among the mutant, the control, and the Bm17 repaired virus strains. These results suggest that BM17 is not essential for virus replication in cultured cells.

  • ORIGINAL RESEARCH Characterization of Bombyx Mori Nucleopolyhedrovirus with a knockout of Bm17
    2011
    Co-Authors: Hongxing Shen, Zhong-jian Guo, Wen Zhang, Bin Nin, Yang Zhou, Shihe Shao, Huiqing Chen, Hua Wang, Xiaochun Wang, Xiaoyong Liu
    Abstract:

    Abstract Open reading frame 17 (Bm17) gene of Bombyx Mori Nucleopolyhedrovirus is a highly con-served gene in lepidopteran Nucleopolyhedroviruses, but its function remains unknown. In this report, transient-expression and superinfection assays indi-cated that BM17 localized in the nucleus and cytoplasm of infected BmN cells. To determine the role of Bm17 in baculovirus life cycle, we constructed a Bm17 knockout virus and characterized its properties in cells. Analysis of the production and infection of budded virions, the level of viral DNA replication revealed showed that there was no significant differ-ence among the mutant, the control, and the Bm17 repaired virus strains. These results suggest that BM17 is not essential for virus replication in cultured cells

  • Identification of a novel functional nuclear localization signal in the protein encoded by open reading frame 47 of Bombyx Mori Nucleopolyhedrovirus.
    Archives of virology, 2010
    Co-Authors: Zhong-jian Guo, Keping Chen, Qin Yao, Dian-xuan Wang, Chuan-xi Zhang
    Abstract:

    BM47 is encoded by open reading frame 47 of Bombyx Mori Nucleopolyhedrovirus (BmNPV). BM47 was localized in the nucleus of BmNPV-infected cells. In the present study, we investigated a novel nuclear localization signal (NLS) for BM47 transport and accumulation in the nucleus. By expressing various regions of BM47 fused to enhanced green fluorescent protein (EGFP), we demonstrated that residues 117–148 are necessary for mediating nuclear localization of BM47. Site-directed mutation analysis showed that the two basic residue clusters at positions 117–120 (117RKRR) and 144–148 (144RKR-K) constitute an authentic NLS for BM47 localization. Finally, we observed that two clusters of basic residues were conserved in BM47 homologues of group-I Nucleopolyhedroviruses.