• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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• pp.35-38
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• 2007

In this study, ORF 46 of Bombyx mod nucleopolyhedrovirus(Bm46) fused with EGFP was expressed in Bombyx mod cell lines, larvae and pupae by BmNPV Bacmid system. Bm46 and EGFP were cloned into donor plasmid pFastBacHTb, which was transformed to competent DH10B cells containing helper and BmNPV bacmid by site-specific transposition. Recombinant bacmid was used to transfected BmN-4 cells to produce the recombinant baculovirus vBm-Bm46-EGFP. Recombination virus was injected into silkworm larvae and pupae. The expression of the fusion protein was monitored by examining green fluorescence using a fluorescent microscope. Intense fluorescence in cells and silkworm was observed at 4 days post-infection, indicating the Bm46-EGFP fusion gene was expressed successfully.

• BMB Reports
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• v.39 no.6
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• pp.737-742
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• 2006

Open reading frame 60 of Bombyx mori nucleopolyhedrovirus (Bm60) is located between 56,673 and 57,479 bp in the BmNPV genome which encodes 268 amino acid residues with predicted molecular weight of 31.0 kDa. Bm60 and its homologues have been identified in 11 completely sequenced lepidopteran NPVs. The transcript of Bm60 was detected by RT-PCR at 18-72 h post-infection (p.i.), while the corresponding protein could be detected at 24-72 h p.i. in BmNPV-infected BmN cells by Western blot analysis using a polyclonal antibody against Bm60. The expression of Bm60 was inhibited in the presence of Ara-c, an inhibitor of viral DNA synthesis. These results together indicated that Bm60 was a late gene. The size of Bm60 product was found to be a 31 kDa in BmNPV-infected BmN cells, consistent with predicted molecular weight. Immuno-fluoresence analysis showed that the Bm60 product was first detected in the cytoplasm at 24 h p.i and also located in nucleus during later infection. In conclusion, the available data suggest that Bm60 is a functional ORF of BmNPV and encodes a 31kDa protein expressed in the later stage of infection cycle.

• International Journal of Industrial Entomology and Biomaterials
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• v.21 no.2
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• pp.157-162
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• 2010

Open reading frame 35 (bm35) of the Bombyx mori nucleopolyhedrovirus (BmNPV) is a special gene whose homologues are only found in some group-I nucleopolyhedroviruses, suggesting that bm35 plays a specific role in the viral life cycle. This paper described the characterization of BmNPV bm35. Computerassisted sequence analysis shows that a putative RING finger motif is observed in the protein, Bm35 encoded by bm35. The coding sequence of bm35 was amplified and subcloned into the vector pET30a(+) and the $(His)_6$-tagged fusion protein His-Bm35 was expressed in the Escherichia coli BL21 (DE3) LysS cells. The bm35 transcript and Bm35 protein were detected in BmNPV-infected BmN cells at 12~48 h post infection (p.i.) by RT-PCR and Western blot analysis using the polyclonal antibody generated by immunizing a rabbit with purified $(His)_6$-tagged Bm35, suggesting that bm35 is synthesized in the late stage of BmNPV infection cycle. Bm35 was not a structural component associated with budded virus (BV) and occlusion derived virus (ODV). These data indicated that bm35 is a functional gene in the BmNPV life cycle.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.53-62
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• 2012

Silkworm larvae often suffer from viral infections causing heavy losses to the economy of silk industry. Insects exhibit both humoral and cellular immune responses that are effective against various pathohens like bacteria, fungi, protozoa, etc., but no insect immune responses is effective against viral infection. To obtain genes related to insect antiviral immunity from Bombyx mori, the cDNA library was constructed from B. mori nucleopolyhedrovirus (BmNPV)-infected B. mori. From the cDNA library, we selected 411 differentially expressed clones, and the 5' ends of the inserts were sequenced to generate ESTs. In this work, 135 unigenes were generated after the assembly of 411 differentially expressed clones ESTs. Of these 135 unigenes, we selected 109 antiviral response-related candidates except 26 clones that high similarity with genes derived from BmNPV. Among 109 unigenes, a total of 80% had significant matches to genes from other organisms in the database, wheres 20% of the unigenes had not matched in the database. Functional groups of these sequences with matches in database were constructed according to their putative biological function. Three largest categories were control of cellular oraganization (52%), metabolism (20%), and protein fate (10%). The genetic information reported in this study will provide more information about antiviral-related genes in silkworms.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.169-174
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• 2004

Bombyx mori nucleopolyhedrovirus(BmNPV) ecdysteroid UDP-glucosyltransferase gene (egt) promoter fragments of different lengths were amplified from BmNPV ZJ-8 genomic DNA by PCR. Reporter plasmids pBmegt542-luc, pBmegt309-luc and pBmegtl59-luc with luciferase (lue) driven by egt promoters were constructed. Both in vitro and in vivo expressions showed that BmNPV egt promoter activity requires the transactivation of viral factor(s), and expression of luc was detected earliest at 24 hrs post infection (pi). BmNPV ZJ-8 homologous region 3 (hr3) increased the expression of luc by over 1,600-fold. Molting hormone of 1.0 - 2.0 $\mu\textrm{g}$/$m\ell$ can dramatically down regulate expression of luc. Juvenile hormone analogue of 0.5-2.0 ${\mu}g$/$m\ell$ increased expression of luc by 145.8% to 75.7%. Deletion assay revealed that the promoter fragment of 159 bp contains the basal promoter structure; Promoter fragments of 309 bp and 542 bp showed similar but much higher transcriptional activities than that of 159 bp, suggesting that nucleotide from -159 to -309 nt upstream the translation initiation site harbors the main cis-acting elements.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.18-24
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• 2001

Expression of the baculovirus major envelope glycoprotein gene(gp64) is regulated by transcription from botha early and late promoters. To develop a transient expression vector under the control of gp64 gene promoter, the gp64 gene of Bombyx mori nucleopolyhedrovirus-K1(BmNPV-K1) was characterized. The gp64 gene was local-ized at EcoR I-Pst I 7.38-kb fragment of the BmNPV-K1 genome. The EcorR 1-Pst I 7.38-kb fragment was cloned and the nucleotide sequence of 2,277 bases including the coding region of gp64 gene was determined. Based on these results, transient expression vector using gp64 gene promoter was constructed and named as pBm64. E.coli lacZ gene was introduced onto pBm64 as a reporter gene and expressed transiently in B. mori 5(Bm 5) cells. The expression vector transfected into the cells was maintained stably for 1 to 5 days. In order to confirm the expression of the reporter gene by gp64 promoter, recombinant virus was constructed. The recombinant virus has two independent transcription units in opposite orientations with two promoters; gp64 and polyhedrin gene promoters each initiating transcription of $\beta$-galactosidase and polyhedrin, respectively. Polyhedra formation and expression of $\beta$-galactosidase in Bm5 cells infected with the recombinant virus were observed with phase contrast microscope and in situ staining.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 1997.06a
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• pp.73-101
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• 1997

Baculoviruses are characterized by large double-stranded circular DNA genomes and rod-shaped enveloped virions. Bombyx mori nucleopolyhedrovirus(BmNPV) is a major pathogen, which causes severe damage in sericulture. Currently, BmNPV is recogtnized as an improtant tool in molecular biology, especially for expression of useful genes in B.mori cells and silkworm larvae. Our laboratories have focused on the studies of the molecular mechanisms of BmNPV replication and the application of BmNPV to agriculture and medicine. The entire nucleotide sequence of the BmNPV genome has recently determined. The BmNPV genome possessed 135 putative genes and 7 homologous repeated sequence (hrs) regions. Relatively little space, a few to a few hundred base-pairs, was observed between the open reading frames and hrs. Termination codons often overlapped. These results showed a compactly packde BmNPV genome. Based on comparative sequence analyses, we speculated that the ancestor of BmNPV was a baculovirus similar to Autographa californica NPV(AcNPV). The function of the BmNPV genes were characterized by gene deletion analysis; p35 was found to be involved in blocking apoptosis and cysteine proteinase was found to be involved in horizontal virus transmission by degrading viral-infected larval host. By AcNPV and BmNPV coinfection experiments, we identified a BmNPV gene involved in expanding host specificity of AcNPV. The identified gene was likely encoded a DNA helicase based on the amino acid sequence analysis; a few amino acid substitutions in the putative DNA helicase gene resulted in the expansion of host range of AcNPV. These findings indicate that BmNPV evolved within a short period from an AcNPV-like ancestral virus due to rapid evolution including specific amino acid substitutions and gene deletions/insertions.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.05a
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• pp.110-110
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• 2001

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2004.05a
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• pp.172-172
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• 2004

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2001.04a
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• pp.31-31
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• 2001

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