Functional role of the cytoplasmic tail domain of the major envelope fusion protein of group II baculoviruses

G. Long, M. Pan, M. Westenberg, J.M. Vlak

Research output: Contribution to journalArticleAcademicpeer-review

17 Citations (Scopus)

Abstract

F proteins from baculovirus nucleopolyhedrovirus (NPV) group II members are the major budded virus (BV) viral envelope fusion proteins. They undergo furin-like proteolysis processing in order to be functional. F proteins from different baculovirus species have a long cytoplasmic tail domain (CTD), ranging from 48 (Spodoptera litura multicapsid NPV [MNPV]) to 78 (Adoxophyes honmai NPV) amino acid (aa) residues, with a nonassigned function. This CTD is much longer than the CTD of GP64-like envelope fusion proteins (7 aa), which appear to be nonessential for BV infectivity. Here we have investigated the functional role of the CTD of Helicoverpa armigera single-capsid NPV (HearNPV), a group II NPV. We combined a newly constructed HearNPV f-null bacmid knockout-repair system and an Autographa californica MNPV (AcMNPV) gp64-null bacmid knockout-pseudotype system with mutation and rescue experiments to study the functional role of the baculovirus F protein CTD. We show that except for the 16 C-terminal aa, the HearNPV F CTD is essential for virus spread from cell to cell. In addition, the CTD of HearNPV F is involved in BV production in a length-dependent manner and is essential for BV infectivity. The tyrosine residue Y658, located 16 aa from the C terminus, seems to be critical. However, HearNPV F without a CTD still rescues the infectivity of gp64-null AcMNPV BV, indicating that the CTD is not involved in processing and fusogenicity. Altogether, our results indicate that the F protein is essential for baculovirus BV infectivity and that the CTD is important for F protein incorporation into BV.
Original languageEnglish
Pages (from-to)11226-11234
JournalJournal of Virology
Volume80
Issue number22
DOIs
Publication statusPublished - 2006

Keywords

  • californica multicapsid nucleopolyhedrovirus
  • virus env protein
  • membrane-fusion
  • transmembrane protein
  • cell-surface
  • r-peptide
  • glycoprotein
  • identification
  • truncation
  • cleavage

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