Absence of N-linked Glycans from the F2 Subunit of the Major Baculovirus Envelope Fusion Protein F Enhances Fusogenicity.
From: State Key Laboratory of Virology, Key Laboratory of Molecular Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People’s Republic of China.
The Journal of general virology
- Publish Date: Feb 2007
- ISSN: 0022-1317
- Volume: 88
- Issue: Pt 2
- Pages: 441-9
- Medium: Print
- Language: English
- Citation (JAMA): Long Gang, Pan Xiaoyu, Vlak Just M, et al. Absence of N-linked Glycans from the F2 Subunit of the Major Baculovirus Envelope Fusion Protein F Enhances Fusogenicity.. J. Gen. Virol. Feb 2007;88:441-9
Abstract
The F protein is the major glycoprotein present in the envelopes of budded virus (BV) of members of the family Baculoviridae. The F protein mediates low-pH-activated fusion with insect cell membranes. Baculovirus F proteins are synthesized as a precursor (F(0)) and cleaved post-translationally into two disulfide-bonded subunits, F(1) (C-terminal, large subunit) and F(2) (N-terminal, small subunit). Recently, N-linked glycosylation of the F(1) and F(2) subunits of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) was demonstrated [Long, G., Westenberg, M., Wang, H., Vlak, J. M. & Hu, Z. (2006). J Gen Virol 87, 839-846]. Sequence analysis frequently predicts that one or more N-linked glycosylation sites are present in the F(2) subunit of baculovirus F proteins. N-glycans on envelope fusion proteins are usually required for proper conformational integrity and biological function, such as infectivity. This study examined the importance of N-linked glycosylation of the F(2) subunit of HearNPV by site-directed mutagenesis. The only putative N-linked glycosylation site in F(2) was eliminated by mutating asparagine (N(104)) to glutamine (Q), resulting in the mutant HearNPV(fN104Q). When inserted into an f-null HearNPV and a gp64-null bacmid of Autographa californica multiple nucleopolyhedrovirus, infectious BV could be retrieved that contained unglycosylated F(2). The virulence of HearNPV(fN104Q) was enhanced, as BV was produced earlier after infection and yielded larger plaques than f-null HearNPV repaired with the wild-type f gene. HearNPV(fN104Q) BV also induced much more efficient low-pH-activated syncytium formation. These results indicate that N-linked glycosylation of the HearNPV baculovirus F(2) subunit is not essential for viral infectivity and suggest that it is involved in BV production and fusogenicity.
Mesh Headings (Keywords): Animals, Cells, Cultured, Giant Cells, Glucans, Glycosylation, Lepidoptera, Membrane Fusion, Mutagenesis, Site-Directed, Nucleopolyhedrovirus, Spodoptera, Viral Fusion Proteins, Virulence
Check for Full Text / PubMed Unique Identifier (PMID): 17251561
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.