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Dong ZQ, Hu N, Zhang J, Chen TT, Cao MY, Li HQ, Lei XJ, Chen P, Lu C, Pan MH. Oligomerization of Baculovirus LEF-11 Is Involved in Viral DNA Replication. PLoS One 2015; 10:e0144930. [PMID: 26660313 PMCID: PMC4678028 DOI: 10.1371/journal.pone.0144930] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/25/2015] [Indexed: 11/18/2022] Open
Abstract
We have previously reported that baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV) late expression factor 11 (lef-11) is associated with viral DNA replication and have demonstrated that it potentially interacts with itself; however, whether LEF-11 forms oligomers and the impact of LEF-11 oligomerization on viral function have not been substantiated. In this study, we first demonstrated that LEF-11 is capable of forming oligomers. Additionally, a series of analyses using BmNPV LEF-11 truncation mutants indicated that two distinct domains control LEF-11 oligomerization (aa 42–61 and aa 72–101). LEF-11 truncation constructs were inserted into a lef-11-knockout BmNPV bacmid, which was used to demonstrate that truncated LEF-11 lacking either oligomerization domain abrogates viral DNA replication. Finally, site-directed mutagenesis was used to determine that the conserved hydrophobic residues Y58&I59 (representing Y58 and I59), I85 and L88&L89 (representing L88 and L89) are required for LEF-11 oligomerization and viral DNA replication. Collectively, these data indicate that BmNPV LEF-11 oligomerization influences viral DNA replication.
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Affiliation(s)
- Zhan-Qi Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Nan Hu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Jun Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
- Institutes of Life Sciences, Chongqing Medical University, Chongqing, 400716, China
| | - Ting-Ting Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Ming-Ya Cao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Hai-Qing Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Xue-Jiao Lei
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Peng Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, 400716, China
- * E-mail: (CL); (MP)
| | - Min-Hui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, 400716, China
- * E-mail: (CL); (MP)
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Lin P, Cheng T, Jin S, Wu Y, Fu B, Long R, Zhao P, Xia Q. PC, a Novel Oral Insecticidal Toxin from Bacillus bombysepticus Involved in Host Lethality via APN and BtR-175. Sci Rep 2015; 5:11101. [PMID: 26057951 PMCID: PMC4460869 DOI: 10.1038/srep11101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 05/13/2015] [Indexed: 01/31/2023] Open
Abstract
Insect pests have developed resistance to chemical insecticides, insecticidal toxins as bioinsecticides or genetic protection built into crops. Consequently, novel, orally active insecticidal toxins would be valuable biological alternatives for pest control. Here, we identified a novel insecticidal toxin, parasporal crystal toxin (PC), from Bacillus bombysepticus (Bb). PC shows oral pathogenic activity and lethality towards silkworms and Cry1Ac-resistant Helicoverpa armigera strains. In vitro assays, PC after activated by trypsin binds to BmAPN4 and BtR-175 by interacting with CR7 and CR12 fragments. Additionally, trypsin-activated PC demonstrates cytotoxicity against Sf9 cells expressing BmAPN4, revealing that BmAPN4 serves as a functional receptor that participates in Bb and PC pathogenicity. In vivo assay, knocking out BtR-175 increased the resistance of silkworms to PC. These data suggest that PC is the first protein with insecticidal activity identified in Bb that is capable of causing silkworm death via receptor interactions, representing an important advance in our understanding of the toxicity of Bb and the contributions of interactions between microbial pathogens and insects to disease pathology. Furthermore, the potency of PC as an insecticidal protein makes it a good candidate for inclusion in integrated agricultural pest management systems.
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Affiliation(s)
- Ping Lin
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Tingcai Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Shengkai Jin
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Yuqian Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Bohua Fu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Renwen Long
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
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Zhang J, Dong ZQ, Zhang CD, He Q, Chen XM, Cao MY, Li HQ, Xiao WF, Lu C, Pan MH. Identification of a novel nuclear localization signal of baculovirus late expression factor 11. Virus Res 2014; 184:111-9. [DOI: 10.1016/j.virusres.2014.02.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/20/2014] [Accepted: 02/26/2014] [Indexed: 10/25/2022]
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Bombyx mori nucleopolyhedrovirus ORF79 is a per os infectivity factor associated with the PIF complex. Virus Res 2014; 184:62-70. [PMID: 24583368 DOI: 10.1016/j.virusres.2014.02.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/13/2014] [Accepted: 02/13/2014] [Indexed: 11/23/2022]
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) ORF79 (Bm79) encodes an occlusion-derived virus (ODV)-specific envelope protein, which is a homologue of the per os infectivity factor 4 (PIF4) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV). To investigate the role of ORF79 in the BmNPV life cycle, a Bm79 knockout virus (vBm(Bm79KO)) was constructed through homologous recombination in Escherichia coli. Viral DNA replication, budded virus (BV) production and polyhedra formation were unaffected by the absence of BM79. However, results of the larval bioassay demonstrated that the Bm79 deletion resulted in a complete loss of per os infection. Immunofluorescence analysis showed that BM79 localized at the innernuclear membrane of infected cells through its N-terminal sorting motif (SM). Further bimolecular fluorescence protein complementation and co-immunoprecipitation assays demonstrated the interaction of BM79 with PIF1, PIF2, PIF3 and ODV-E66. Thus, BM79 plays an important role in per os infection and is associated with the viral PIF complex of BmNPV.
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