Baculovirus per os infectivity factor complex

Components and assembly

Xi Wang, Yu Shang, Cheng Chen, Shurui Liu, Meng Chang, Nan Zhang, Hengrui Hu, Fenghua Zhang, Tao Zhang, Zhiying Wang, Xijia Liu, Zhe Lin, Fei Deng, Hualin Wang, Zhen Zou, Just M. Vlak, Manli Wang*, Zhihong Hu

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)

Abstract

Baculovirus entry into insect midgut cells is dependent on a multiprotein complex of per os infectivity factors (PIFs) on the envelopes of occlusion-derived virions (ODVs). The structure and assembly of the PIF complex are largely unknown. To reveal the complete members of the complex, a combination of blue native polyacrylamide gel electrophoresis, liquid chromatography-tandem mass spectrometry, and Western blotting was conducted on three different baculoviruses. The results showed that the PIF complex has a molecular mass of ~500 kDa and consists of nine PIFs, including a newly discovered member (PIF9). To decipher the assembly process, each pif gene was knocked out from the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) genome individually by use of synthetic baculovirus technology, and the impact on PIF complex formation was investigated. Deletion of pif8 resulted in the formation of an ~400-kDa subcomplex. Deletion of pif0, -4, -6, -7, or -9 resulted in a subcomplex of ~230 kDa, but deletion of pif1, -2, or -3 abolished formation of any complex. Taken together, our data identified a core complex of ~230 kDa, consisting of PIF1, -2, and -3. This revised the previous knowledge that the core complex was about 170 kDa and contained PIF1 to -4. Analysis of the PIF complex in cellular fractions suggested that it is assembled in the cytoplasm before being transported to the nucleus and subsequently incorporated into the envelopes of ODVs. Only the full complex, not the subcomplex, is resistant to proteolytic attack, indicating the essentiality of correct complex assembly for oral infection. IMPORTANCE Entry of baculovirus into host insects is mediated by a per os infectivity factor (PIF) complex on the envelopes of occlusion-derived viruses (ODVs). Knowledge of the composition and structure of the PIF complex is fundamental to understanding its mode of action. By using multiple approaches, we determined the complete list of proteins (nine) in the PIF complex. In contrast to previous knowledge in the field, the core complex is revised to ~230 kDa and consists of PIF1 to -3 but not PIF4. Interestingly, our results suggest that the PIF complex is formed in the cytoplasm prior to its transport to the nucleus and subsequent incorporation into ODVs. Only the full complex is resistant to proteolytic degradation in the insect midgut, implying the critical role of the entire complex. These findings provide the baseline for future studies on the ODV entry mechanism mediated by the multiprotein complex.

Original languageEnglish
Article numbere02053-18
JournalJournal of Virology
Volume93
Issue number6
DOIs
Publication statusPublished - 1 Mar 2019

Fingerprint

Baculoviridae
Virion
pathogenicity
Insects
Multiprotein Complexes
Cytoplasm
virion
Nucleopolyhedrovirus
Native Polyacrylamide Gel Electrophoresis
multiprotein complexes
Tandem Mass Spectrometry
Liquid Chromatography
midgut
Western Blotting
insects
Genome
Viruses
Technology
cytoplasm
Autographa californica multiple nucleopolyhedrovirus

Keywords

  • Baculovirus
  • Entry
  • Per os infectivity factor
  • PIF complex
  • PIF9

Cite this

Wang, X., Shang, Y., Chen, C., Liu, S., Chang, M., Zhang, N., ... Hu, Z. (2019). Baculovirus per os infectivity factor complex: Components and assembly. Journal of Virology, 93(6), [e02053-18]. https://doi.org/10.1128/JVI.02053-18
Wang, Xi ; Shang, Yu ; Chen, Cheng ; Liu, Shurui ; Chang, Meng ; Zhang, Nan ; Hu, Hengrui ; Zhang, Fenghua ; Zhang, Tao ; Wang, Zhiying ; Liu, Xijia ; Lin, Zhe ; Deng, Fei ; Wang, Hualin ; Zou, Zhen ; Vlak, Just M. ; Wang, Manli ; Hu, Zhihong. / Baculovirus per os infectivity factor complex : Components and assembly. In: Journal of Virology. 2019 ; Vol. 93, No. 6.
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title = "Baculovirus per os infectivity factor complex: Components and assembly",
abstract = "Baculovirus entry into insect midgut cells is dependent on a multiprotein complex of per os infectivity factors (PIFs) on the envelopes of occlusion-derived virions (ODVs). The structure and assembly of the PIF complex are largely unknown. To reveal the complete members of the complex, a combination of blue native polyacrylamide gel electrophoresis, liquid chromatography-tandem mass spectrometry, and Western blotting was conducted on three different baculoviruses. The results showed that the PIF complex has a molecular mass of ~500 kDa and consists of nine PIFs, including a newly discovered member (PIF9). To decipher the assembly process, each pif gene was knocked out from the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) genome individually by use of synthetic baculovirus technology, and the impact on PIF complex formation was investigated. Deletion of pif8 resulted in the formation of an ~400-kDa subcomplex. Deletion of pif0, -4, -6, -7, or -9 resulted in a subcomplex of ~230 kDa, but deletion of pif1, -2, or -3 abolished formation of any complex. Taken together, our data identified a core complex of ~230 kDa, consisting of PIF1, -2, and -3. This revised the previous knowledge that the core complex was about 170 kDa and contained PIF1 to -4. Analysis of the PIF complex in cellular fractions suggested that it is assembled in the cytoplasm before being transported to the nucleus and subsequently incorporated into the envelopes of ODVs. Only the full complex, not the subcomplex, is resistant to proteolytic attack, indicating the essentiality of correct complex assembly for oral infection. IMPORTANCE Entry of baculovirus into host insects is mediated by a per os infectivity factor (PIF) complex on the envelopes of occlusion-derived viruses (ODVs). Knowledge of the composition and structure of the PIF complex is fundamental to understanding its mode of action. By using multiple approaches, we determined the complete list of proteins (nine) in the PIF complex. In contrast to previous knowledge in the field, the core complex is revised to ~230 kDa and consists of PIF1 to -3 but not PIF4. Interestingly, our results suggest that the PIF complex is formed in the cytoplasm prior to its transport to the nucleus and subsequent incorporation into ODVs. Only the full complex is resistant to proteolytic degradation in the insect midgut, implying the critical role of the entire complex. These findings provide the baseline for future studies on the ODV entry mechanism mediated by the multiprotein complex.",
keywords = "Baculovirus, Entry, Per os infectivity factor, PIF complex, PIF9",
author = "Xi Wang and Yu Shang and Cheng Chen and Shurui Liu and Meng Chang and Nan Zhang and Hengrui Hu and Fenghua Zhang and Tao Zhang and Zhiying Wang and Xijia Liu and Zhe Lin and Fei Deng and Hualin Wang and Zhen Zou and Vlak, {Just M.} and Manli Wang and Zhihong Hu",
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language = "English",
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journal = "Journal of Virology",
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Wang, X, Shang, Y, Chen, C, Liu, S, Chang, M, Zhang, N, Hu, H, Zhang, F, Zhang, T, Wang, Z, Liu, X, Lin, Z, Deng, F, Wang, H, Zou, Z, Vlak, JM, Wang, M & Hu, Z 2019, 'Baculovirus per os infectivity factor complex: Components and assembly', Journal of Virology, vol. 93, no. 6, e02053-18. https://doi.org/10.1128/JVI.02053-18

Baculovirus per os infectivity factor complex : Components and assembly. / Wang, Xi; Shang, Yu; Chen, Cheng; Liu, Shurui; Chang, Meng; Zhang, Nan; Hu, Hengrui; Zhang, Fenghua; Zhang, Tao; Wang, Zhiying; Liu, Xijia; Lin, Zhe; Deng, Fei; Wang, Hualin; Zou, Zhen; Vlak, Just M.; Wang, Manli; Hu, Zhihong.

In: Journal of Virology, Vol. 93, No. 6, e02053-18, 01.03.2019.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Baculovirus per os infectivity factor complex

T2 - Components and assembly

AU - Wang, Xi

AU - Shang, Yu

AU - Chen, Cheng

AU - Liu, Shurui

AU - Chang, Meng

AU - Zhang, Nan

AU - Hu, Hengrui

AU - Zhang, Fenghua

AU - Zhang, Tao

AU - Wang, Zhiying

AU - Liu, Xijia

AU - Lin, Zhe

AU - Deng, Fei

AU - Wang, Hualin

AU - Zou, Zhen

AU - Vlak, Just M.

AU - Wang, Manli

AU - Hu, Zhihong

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Baculovirus entry into insect midgut cells is dependent on a multiprotein complex of per os infectivity factors (PIFs) on the envelopes of occlusion-derived virions (ODVs). The structure and assembly of the PIF complex are largely unknown. To reveal the complete members of the complex, a combination of blue native polyacrylamide gel electrophoresis, liquid chromatography-tandem mass spectrometry, and Western blotting was conducted on three different baculoviruses. The results showed that the PIF complex has a molecular mass of ~500 kDa and consists of nine PIFs, including a newly discovered member (PIF9). To decipher the assembly process, each pif gene was knocked out from the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) genome individually by use of synthetic baculovirus technology, and the impact on PIF complex formation was investigated. Deletion of pif8 resulted in the formation of an ~400-kDa subcomplex. Deletion of pif0, -4, -6, -7, or -9 resulted in a subcomplex of ~230 kDa, but deletion of pif1, -2, or -3 abolished formation of any complex. Taken together, our data identified a core complex of ~230 kDa, consisting of PIF1, -2, and -3. This revised the previous knowledge that the core complex was about 170 kDa and contained PIF1 to -4. Analysis of the PIF complex in cellular fractions suggested that it is assembled in the cytoplasm before being transported to the nucleus and subsequently incorporated into the envelopes of ODVs. Only the full complex, not the subcomplex, is resistant to proteolytic attack, indicating the essentiality of correct complex assembly for oral infection. IMPORTANCE Entry of baculovirus into host insects is mediated by a per os infectivity factor (PIF) complex on the envelopes of occlusion-derived viruses (ODVs). Knowledge of the composition and structure of the PIF complex is fundamental to understanding its mode of action. By using multiple approaches, we determined the complete list of proteins (nine) in the PIF complex. In contrast to previous knowledge in the field, the core complex is revised to ~230 kDa and consists of PIF1 to -3 but not PIF4. Interestingly, our results suggest that the PIF complex is formed in the cytoplasm prior to its transport to the nucleus and subsequent incorporation into ODVs. Only the full complex is resistant to proteolytic degradation in the insect midgut, implying the critical role of the entire complex. These findings provide the baseline for future studies on the ODV entry mechanism mediated by the multiprotein complex.

AB - Baculovirus entry into insect midgut cells is dependent on a multiprotein complex of per os infectivity factors (PIFs) on the envelopes of occlusion-derived virions (ODVs). The structure and assembly of the PIF complex are largely unknown. To reveal the complete members of the complex, a combination of blue native polyacrylamide gel electrophoresis, liquid chromatography-tandem mass spectrometry, and Western blotting was conducted on three different baculoviruses. The results showed that the PIF complex has a molecular mass of ~500 kDa and consists of nine PIFs, including a newly discovered member (PIF9). To decipher the assembly process, each pif gene was knocked out from the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) genome individually by use of synthetic baculovirus technology, and the impact on PIF complex formation was investigated. Deletion of pif8 resulted in the formation of an ~400-kDa subcomplex. Deletion of pif0, -4, -6, -7, or -9 resulted in a subcomplex of ~230 kDa, but deletion of pif1, -2, or -3 abolished formation of any complex. Taken together, our data identified a core complex of ~230 kDa, consisting of PIF1, -2, and -3. This revised the previous knowledge that the core complex was about 170 kDa and contained PIF1 to -4. Analysis of the PIF complex in cellular fractions suggested that it is assembled in the cytoplasm before being transported to the nucleus and subsequently incorporated into the envelopes of ODVs. Only the full complex, not the subcomplex, is resistant to proteolytic attack, indicating the essentiality of correct complex assembly for oral infection. IMPORTANCE Entry of baculovirus into host insects is mediated by a per os infectivity factor (PIF) complex on the envelopes of occlusion-derived viruses (ODVs). Knowledge of the composition and structure of the PIF complex is fundamental to understanding its mode of action. By using multiple approaches, we determined the complete list of proteins (nine) in the PIF complex. In contrast to previous knowledge in the field, the core complex is revised to ~230 kDa and consists of PIF1 to -3 but not PIF4. Interestingly, our results suggest that the PIF complex is formed in the cytoplasm prior to its transport to the nucleus and subsequent incorporation into ODVs. Only the full complex is resistant to proteolytic degradation in the insect midgut, implying the critical role of the entire complex. These findings provide the baseline for future studies on the ODV entry mechanism mediated by the multiprotein complex.

KW - Baculovirus

KW - Entry

KW - Per os infectivity factor

KW - PIF complex

KW - PIF9

U2 - 10.1128/JVI.02053-18

DO - 10.1128/JVI.02053-18

M3 - Article

VL - 93

JO - Journal of Virology

JF - Journal of Virology

SN - 0022-538X

IS - 6

M1 - e02053-18

ER -

Wang X, Shang Y, Chen C, Liu S, Chang M, Zhang N et al. Baculovirus per os infectivity factor complex: Components and assembly. Journal of Virology. 2019 Mar 1;93(6). e02053-18. https://doi.org/10.1128/JVI.02053-18