Partial Functional Rescue of Helicoverpa armigera Single Nucleocapsid Nucleopolyhedrovirus Infectivity by Replacement of F Protein with GP64 from Autographa californica Multicapsid Nucleopolyhedrovirus
Two distinct envelope fusion proteins (EFPs) (GP64 and F) have been identified in members of the Baculoviridae family of viruses. F proteins are found in group II nucleopolyhedroviruses (NPVs) of alphabaculoviruses and in beta- and deltabaculoviruses, while GP64 occurs only in group I NPVs of alphabaculoviruses. It was proposed that an ancestral baculovirus acquired the gp64 gene that conferred a selective advantage and allowed it to evolve into group I NPVs. The F protein is a functional analogue of GP64, as evidenced from the rescue of gp64-null Autographa californica multicapsid nucleopolyhedrovirus (MNPV) (AcMNPV) by F proteins from group II NPVs or from betabaculoviruses. However, GP64 failed to rescue an F-null Spodoptera exigua MNPV (SeMNPV) (group II NPV). Here, we report the successful generation of an infectious gp64-rescued group II NPV of Helicoverpa armigera (vHaBac Delta F-gp64). Viral growth curve assays and quantitative real-time PCR (Q-PCR), however, showed substantially decreased infectivity of vHaBac Delta F-gp64 compared to the HaF rescue control virus vHaBac Delta F-HaF. Electron microscopy further showed that most vHaBac Delta F-gp64 budded viruses (BV) in the cell culture supernatant lacked envelope components and contained morphologically aberrant nucleocapsids, suggesting the improper BV envelopment or budding of vHaBac Delta F-gp64. Bioassays using pseudotyped viruses with a reintroduced polyhedrin gene showed that GP64-pseudotyped Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearNPV) significantly delayed the mortality of infected H. armigera larvae.
| Main Authors: | , , , , , , , |
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| Format: | Article/Letter to editor biblioteca |
| Language: | English |
| Subjects: | ac23, baculovirus gp64, cells, entry, envelope fusion protein, glycoproteins, homolog, lentiviral vectors, membrane-fusion, nuclear polyhedrosis-virus, |
| Online Access: | https://research.wur.nl/en/publications/partial-functional-rescue-of-helicoverpa-armigera-single-nucleoca |
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