Disruption of Bombyx mori nucleopolyhedrovirus ORF71 (Bm71) results in inefficient budded virus production and decreased virulence in host larvae

Bombyx mori nucleopolyhedrovirus (BmNPV) BmP95 is a highly conserved gene that is found in all of the baculovirus genomes sequenced to date and is also found in nudiviruses. To investigate the role of BmP95 in virus infection in vitro, a BmP95 deletion virus (vBmP95-De) was generated by homologous recombination in Escherichia coli. Fluorescence and light microscopy and titration analysis indicated that the BmP95 deletion bacmid led to a defect in production of infectious budded virus (BV). However, deletion of BmP95 did not affect viral DNA replication. Electron microscopy showed that masses of aberrant tubular structures were present in cells transfected with the BmP95 deletion bacmid, indicating that deletion of BmP95 affected assembly of the nucleocapsid. This defect could be rescued by insertion of full-length BmP95 into the polyhedrin locus of the BmP95-knockout bacmid but not the N-terminal domain of BmP95. Together, these results showed that full-length BmP95 is essential for BV production and is required for nucleocapsid assembly.

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Bombyx mori nucleopolyhedrovirus ORF40 is essential for budded virus production and occlusion-derived virus envelopment

Journal of General Virology ◽

10.1099/jgv.0.001066 ◽

2018 ◽

Vol 99 (6) ◽

pp. 837-850 ◽

Cited By ~ 2

Author(s):

Yunwang Shen ◽

Min Feng ◽

Xiaofeng Wu

Keyword(s):

Bombyx Mori ◽

Virus Production ◽

Bombyx Mori Nucleopolyhedrovirus ◽

Budded Virus

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Bombyx mori nucleopolyhedrovirus ORF9 is a gene involved in the budded virus production and infectivity

Journal of General Virology ◽

10.1099/vir.0.004903-0 ◽

2009 ◽

Vol 90 (1) ◽

pp. 162-169 ◽

Cited By ~ 14

Author(s):

Z.-N. Yang ◽

H.-J. Xu ◽

S. M. Thiem ◽

Y.-P. Xu ◽

J.-Q. Ge ◽

...

Keyword(s):

Bombyx Mori ◽

Virus Production ◽

Bombyx Mori Nucleopolyhedrovirus ◽

Budded Virus

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Bombyx mori nucleopolyhedrovirus ORF56 encodes an occlusion-derived virus protein and is not essential for budded virus production

Journal of General Virology ◽

10.1099/vir.0.83633-0 ◽

2008 ◽

Vol 89 (5) ◽

pp. 1212-1219 ◽

Cited By ~ 30

Author(s):

Hai-Jun Xu ◽

Zhang-Nv Yang ◽

Jin-Fang Zhao ◽

Cai-Hong Tian ◽

Jun-Qing Ge ◽

...

Keyword(s):

Bombyx Mori ◽

Cultured Cells ◽

Virus Production ◽

Core Gene ◽

Virus Protein ◽

Infected Cells ◽

Budded Virus ◽

Larval Bioassay

Bombyx mori nucleopolyhedrovirus ORF56 (Bm56) is a baculovirus core gene that is highly conserved in all baculoviruses that have had their genomes sequenced to date. Its transcripts in BmNPV-infected cells could be detected from 12 h post-infection (p.i.) and the encoded protein could be detected at 16 h p.i. by using a polyclonal antibody against glutathione S-transferase–Bm56 fusion protein. Western blot analysis showed that Bm56 is a structural component of the occlusion-derived virus nucleocapsid. Subsequent confocal microscopy revealed that Bm56 was distributed in the outer nuclear membrane and the intranuclear region of infected cells. To investigate the role of Bm56 in virus replication, a Bm56-knockout bacmid of BmNPV was constructed via homologous recombination in Escherichia coli. The Bm56 deletion had no effect on budded virus (BV) production in cultured cells; however, the deletion affected occlusion-body morphogenesis. A larval bioassay demonstrated that the Bm56 deletion did not reduce infectivity, whereas it resulted in a 50 % lethal time that was 16–18 h longer than that of the wild-type bacmid at every dose used in this study. These results indicate that Bm56 facilitates efficient virus production in vivo; however, it is not essential for BV production in vitro.

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Characterization of Bombyx mori Nucleopolyhedrovirus orf68 Gene That Encodes a Novel Structural Protein of Budded Virus

Virology ◽

10.1006/viro.2002.1443 ◽

2002 ◽

Vol 297 (1) ◽

pp. 39-47 ◽

Cited By ~ 19

Author(s):

Masashi Iwanaga ◽

Masaaki Kurihara ◽

Masahiko Kobayashi ◽

WonKyung Kang

Keyword(s):

Bombyx Mori ◽

Structural Protein ◽

Bombyx Mori Nucleopolyhedrovirus ◽

Budded Virus

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Bombyx mori Nucleopolyhedrovirus p26 Is Associated with Viral Late Stage Replication

Insects ◽

10.3390/insects12080707 ◽

2021 ◽

Vol 12 (8) ◽

pp. 707

Author(s):

Jun-Qing Ge ◽

Zhu-Hong Wang ◽

Xi Chen ◽

Hua Chen ◽

Jian Huang

Keyword(s):

Infected Cell ◽

Bombyx Mori ◽

Infectious Virus ◽

Pcr Analysis ◽

Immunofluorescence Analysis ◽

Bombyx Mori Nucleopolyhedrovirus ◽

Cell Cytoplasm ◽

Infected Cells ◽

Budded Virus ◽

Infection Stage

Bombyx mori nucleopolyhedrovirus (BmNPV) p26 is conserved among all Lepidoptera baculoviruses that have been completely sequenced thus far, and some baculoviruses even have two copies of p26, which suggested that p26 may play an important role in the virus infection cycle. This study aimed to characterize BmNPV p26. We found that BmNPV p26 transcripts were detectable as early as 3 h post-infection (hpi), and the transcript levels rapidly increased starting from 12 hpi. Western blot analysis using an anti-p26 polyclonal antibody demonstrated that the corresponding protein was also detectable from 6 hpi in BmNPV-infected cell lysates. Immunofluorescence analysis demonstrated that p26 was mainly dispersed in the infected cell cytoplasm, whereas the over-expressed fusion protein EGFP-p26 also accumulated in the nucleus. These results indicated that p26 is an early BmNPV gene and has functions both in the cytoplasm and the nucleus. RNAi-based knockdown of p26 could produce infectious virus and normal-appearing virions but decreased budded virus (BV) production in BmNPV-infected cells at 72 hpi. Moreover, the results of further quantitative PCR (Q-PCR) analysis indicated that the gp64 and p74 transcripts levels decreased significantly. These results indicated that BmNPV p26 may be associated with BmNPV replication during the late infection stage.

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