1887

Abstract

Wild-type ODVs (Wt) have an intact ODV entry complex in their envelope and are orally infectious towards insect larvae (left panel). In the absence of Ac108 (mut ac108), the stable core is still present but nevertheless fails to form an entry complex, affecting the ODV oral infectivity (right panel). The components of the core complex are depicted in yellow and the loosely associated components are depicted in red. PIF7 is depicted in green as its affinity with the complex is currently not known.

Baculoviruses orally infect insect larvae when they consume viral occlusion bodies (OBs). OBs consist of a crystalline protein matrix in which the infectious virus particles, the occlusion-derived viruses (ODVs), are embedded. The protein matrix dissolves in the alkaline environment of the insect’s midgut lumen. The liberated ODVs can then infect midgut endothelial cells through the action of at least nine different ODV-envelope proteins, called per os infectivity factors (PIFs). These PIF proteins mediate ODV oral infectivity, but are not involved in the systemic spread of the infection by budded viruses (BVs). Eight of the known PIFs form a multimeric complex, named the ODV entry complex. In this study, we show for Autographa californica multiple nucleopolyhedrovirus that mutation of the ac108ORF abolishes the ODV oral infectivity, while production and infectivity of the BVs remains unaffected. Furthermore, repair of the ac108 mutant completely recovered oral infectivity. With an HA-tagged repair mutant, we were able to demonstrate by Western analysis that the Ac108 protein is a constituent of the ODV entry complex, where the formation was abolished in the absence of this protein. Based on these results, we conclude that ac108 encodes a per os infectivity factor (PIF9) that is also an essential constituent of the ODV entry complex.

Loading

Article metrics loading...

/content/journal/jgv/10.1099/jgv.0.001200
2019-01-29
2019-09-23
Loading full text...

Full text loading...

References

  1. Williams T, Bergoin M, van Oers MM. Diversity of large DNA viruses of invertebrates. J Invertebr Pathol 2017;147:4–22 [CrossRef][PubMed]
    [Google Scholar]
  2. Shi Y, Li K, Tang P, Li Y, Zhou Q et al. Three-dimensional visualization of the Autographa californica multiple nucleopolyhedrovirus occlusion-derived virion envelopment process gives new clues as to its mechanism. Virology 2015;476:298–303 [CrossRef][PubMed]
    [Google Scholar]
  3. Boogaard B, van Oers MM, van Lent JWM. An advanced view on Baculovirus per os Infectivity Factors. Insects 2018;9:83 [CrossRef][PubMed]
    [Google Scholar]
  4. Haas-Stapleton EJ, Washburn JO, Volkman LE. P74 mediates specific binding of Autographa californica M nucleopolyhedrovirus occlusion-derived virus to primary cellular targets in the midgut epithelia of Heliothis virescens Larvae. J Virol 2004;78:6786–6791 [CrossRef][PubMed]
    [Google Scholar]
  5. Ohkawa T, Washburn JO, Sitapara R, Sid E, Volkman LE. Specific binding of Autographa californica M nucleopolyhedrovirus occlusion-derived virus to midgut cells of Heliothis virescens larvae is mediated by products of pif genes ac119 and ac022 but not by ac115. J Virol 2005;79:15258–15264 [CrossRef][PubMed]
    [Google Scholar]
  6. Peng K, van Lent JW, Boeren S, Fang M, Theilmann DA et al. Characterization of novel components of the baculovirus per os infectivity factor complex. J Virol 2012;86:4981–4988 [CrossRef][PubMed]
    [Google Scholar]
  7. Peng K, van Oers MM, Hu Z, van Lent JW, Vlak JM. Baculovirus per os infectivity factors form a complex on the surface of occlusion-derived virus. J Virol 2010;84:9497–9504 [CrossRef][PubMed]
    [Google Scholar]
  8. Boogaard B, van Lent JWM, Theilmann DA, Erlandson MA, van Oers MM. Baculoviruses require an intact ODV entry-complex to resist proteolytic degradation of per os infectivity factors by co-occluded proteases from the larval host. J Gen Virol 2017;98:3101–3110 [CrossRef][PubMed]
    [Google Scholar]
  9. Simón O, Palma L, Williams T, López-Ferber M, Caballero P. Analysis of a naturally-occurring deletion mutant of Spodoptera frugiperda multiple nucleopolyhedrovirus reveals sf58 as a new per os infectivity factor of lepidopteran-infecting baculoviruses. J Invertebr Pathol 2012;109:117–126 [CrossRef][PubMed]
    [Google Scholar]
  10. Tang Q, Li G, Yao Q, Chen L, Lv P et al. Bm91 is an envelope component of ODV but is dispensable for the propagation of Bombyx mori nucleopolyhedrovirus. J Invertebr Pathol 2013;113:70–77 [CrossRef][PubMed]
    [Google Scholar]
  11. Datsenko KA, Wanner BL. One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc Natl Acad Sci USA 2000;97:6640–6645 [CrossRef][PubMed]
    [Google Scholar]
  12. Suzuki N, Nonaka H, Tsuge Y, Inui M, Yukawa H. New multiple-deletion method for the Corynebacterium glutamicum genome, using a mutant lox sequence. Appl Environ Microbiol 2005;71:8472–8480 [CrossRef][PubMed]
    [Google Scholar]
  13. Hopkins R, Esposito D. A rapid method for titrating baculovirus stocks using the Sf-9 Easy Titer cell line. Biotechniques 2009;47:785–788 [CrossRef][PubMed]
    [Google Scholar]
  14. Garavaglia MJ, Miele SA, Iserte JA, Belaich MN, Ghiringhelli PD. The ac53, ac78, ac101, and ac103 genes are newly discovered core genes in the family Baculoviridae. J Virol 2012;86:12069–12079 [CrossRef][PubMed]
    [Google Scholar]
  15. Javed MA, Biswas S, Willis LG, Harris S, Pritchard C et al. AcMNPV AC83 is a PIF protein required for ODV and BV nucleocapsid assembly as well as assembly of the PIF complex in ODV envelopes. J Virol 2016;91:e0211502116
    [Google Scholar]
  16. Li G, Wang J, Deng R, Wang X. Characterization of AcMNPV with a deletion of ac68 gene. Virus Genes 2008;37:119–127 [CrossRef][PubMed]
    [Google Scholar]
  17. Nie Y, Fang M, Erlandson MA, Theilmann DA. Analysis of the Autographa californica multiple nucleopolyhedrovirus overlapping gene pair lef3 and ac68 reveals that AC68 is a per os infectivity factor and that LEF3 is critical, but not essential, for virus replication. J Virol 2012;86:3985–3994 [CrossRef][PubMed]
    [Google Scholar]
  18. Xu HJ, Yang ZN, Zhao JF, Tian CH, Ge JQ et al. Bombyx mori nucleopolyhedrovirus ORF56 encodes an occlusion-derived virus protein and is not essential for budded virus production. J Gen Virol 2008;89:1212–1219 [CrossRef][PubMed]
    [Google Scholar]
  19. Sa L, Li L, Zhao HZ, Liu WH. Disruption of Autographa californica Multiple Nucleopolyhedrovirus ac111 Results in Reduced per os Infectivity in a Host-Dependent Manner. Viruses 2018;10:
    [Google Scholar]
  20. Luo S, Zhang Y, Xu X, Westenberg M, Vlak JM et al. Helicoverpa armigera nucleopolyhedrovirus occlusion-derived virus-associated protein, HA100, affects oral infectivity in vivo but not virus replication in vitro. J Gen Virol 2011;92:1324–1331 [CrossRef][PubMed]
    [Google Scholar]
  21. Ahrens CH, Russell RL, Funk CJ, Evans JT, Harwood SH et al. The sequence of the Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis virus genome. Virology 1997;229:381–399 [CrossRef][PubMed]
    [Google Scholar]
  22. Chen W, Li Z, Li S, Li L, Yang K et al. Identification of Spodoptera litura multicapsid nucleopolyhedrovirus ORF97, a novel protein associated with envelope of occlusion-derived virus. Virus Genes 2006;32:79–84 [CrossRef]
    [Google Scholar]
  23. Shi SL, Pan MH, Lu C. Characterization of Antheraea pernyi nucleopolyhedrovirus p11 gene, a homologue of Autographa californica nucleopolyhedrovirus orf108. Virus Genes 2007;35:97–101 [CrossRef][PubMed]
    [Google Scholar]
  24. Fang M, Nie Y, Harris S, Erlandson MA, Theilmann DA. Autographa californica multiple nucleopolyhedrovirus core gene ac96 encodes a per os infectivity factor (PIF-4). J Virol 2009;83:12569–12578 [CrossRef][PubMed]
    [Google Scholar]
  25. Zheng Q, Shen Y, Kon X, Zhang J, Feng M et al. Protein-protein interactions of the baculovirus per os infectivity factors (PIFs) in the PIF complex. J Gen Virol 2017;98:853–861 [CrossRef][PubMed]
    [Google Scholar]
  26. Luckow VA, Lee SC, Barry GF, Olins PO. Efficient generation of infectious recombinant baculoviruses by site-specific transposon-mediated insertion of foreign genes into a baculovirus genome propagated in Escherichia coli. J Virol 1993;67:4566–4579[PubMed]
    [Google Scholar]
  27. Smith GE, Summers MD. Restriction Maps of 5 Autographa MNPV Variants, Trichoplusia ni MNPV, and Galleria mellonella MNPV DNAs with endonucleases SmaI, KpnI, BamhI, SacI, XhoI, and EcoRI. J Virol 1979;30:828–838[PubMed]
    [Google Scholar]
  28. Westenberg M, Soedling HM, Mann DA, Nicholson LJ, Dolphin CT. Counter-selection recombineering of the baculovirus genome: a strategy for seamless modification of repeat-containing BACs. Nucleic Acids Res 2010;38:e166e166 [CrossRef][PubMed]
    [Google Scholar]
  29. Ros VI, van Houte S, Hemerik L, van Oers MM. Baculovirus-induced tree-top disease: how extended is the role of egt as a gene for the extended phenotype?. Mol Ecol 2015;24:249–258 [CrossRef][PubMed]
    [Google Scholar]
  30. Russell RL, Rohrmann GF. Characterization of P91, a protein associated with virions of an Orgyia pseudotsugata baculovirus. Virology 1997;233:210–223 [CrossRef][PubMed]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/jgv/10.1099/jgv.0.001200
Loading
/content/journal/jgv/10.1099/jgv.0.001200
Loading

Data & Media loading...

Supplementary File 1

PDF

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error