In Situ cleavage of Baculovirus occlusion-derived virus receptor binding protein P74 in the peroral infectivity complex

Proteolytic processing of viral membrane proteins is common among enveloped viruses to facilitate virus entry. The Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) occlusion derived virus (ODV) protein P74 is part of a complex of essential peroral infectivity factors (PIFs). Here we report that P74 is efficiently cleaved into two fragments of about equal size by an OB endogenous alkaline protease during ODV release when AcMNPV occlusion bodies (OB) are derived from larvae. The cleavage is specific for P74 since the other known peroral infectivity factors in the same complex (PIF1, PIF2 and PIF3) were not cleaved under the same conditions. P74 cleavage was not observed in OBs produced in three different insect cell lines suggesting a larval host origin of the responsible protease. P74 in OBs produced in larvae of two different host species was cleaved into fragments with the same apparent molecular mass indicating that the virus incorporates a similar alkaline protease from different hosts. Co-immunoprecipitation analysis revealed that the two P74 subunit fragments remain associated with the recently discovered PIF complex. We propose that under in vivo ODV infection conditions P74 undergoes two sequential cleavage events, the first one being performed by an ODV-associated host alkaline protease and the second carried out by trypsin in the host midgut

Bibliographic Details

Main Authors:	Peng, K., van Lent, J.W.M., Vlak, J.M., Hu, Zhihong, van Oers, M.M.
Format:	Article/Letter to editor biblioteca
Language:	English
Subjects:	alkaline protease, autographa-californica, envelope protein, granulosis-virus, heliothis-virescens larvae, nuclear-polyhedrosis-virus, per-os infectivity, proteolytic cleavage, trichoplusia-ni, viral entry,
Online Access:	https://research.wur.nl/en/publications/in-situ-cleavage-of-baculovirus-occlusion-derived-virus-receptor-
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