Functional role of the glycan cluster of the human immunodeficiency virus type 1 transmembrane glycoprotein (gp41) ectodomain
- PMID: 8093218
- PMCID: PMC237347
- DOI: 10.1128/JVI.67.1.150-160.1993
Functional role of the glycan cluster of the human immunodeficiency virus type 1 transmembrane glycoprotein (gp41) ectodomain
Abstract
To examine the role of the glycans of human immunodeficiency virus type 1 transmembrane glycoprotein gp41, conserved glycosylation sites within the env sequence (Asn-621, Asn-630, and Asn-642) were mutated to Gln. The mutated and control wild-type env genes were introduced into recombinant vaccinia virus and used to infect BHK-21 or CD4+ CEM cells. Mutated gp41 appeared as a 35-kDa band in a Western blot (immunoblot), and it comigrated with the deglycosylated form of wild-type gp41. Proteolytic cleavage of the recombinant wild-type and mutant forms of the gp160 envelope glycoprotein precursor was analyzed by pulse-chase experiments and enzyme-linked immunosorbent assay: gp160 synthesis was similar whether cells were infected with control or mutated env-expressing recombinant vaccinia virus, but about 10-fold less cleaved gp120 and gp41 was produced by the mutated construct than the control construct. The rates of gp120-gp41 cleavage at each of the two potential sites appeared to be comparable in the two constructs. By using a panel of antibodies specific for gp41 and gp120 epitopes, it was shown that the overall immunoreactivities of control and mutated gp41 proteins were similar but that reactivity to epitopes at the C and N termini of gp120, as present on gp160 produced by the mutated construct, was enhanced. This was no longer observed for cleaved gp120 in supernatants. Both gp120 proteins, from control and mutated env, were expressed on the cell surface under a cleaved form and could bind to membrane CD4, as determined by quantitative immunofluorescence assay. In contrast, and despite sufficient expression of env products at the cell membrane, gp41 produced by the mutated construct was unable to induce membrane fusion. Therefore, while contradictory results reported in the literature suggest that gp41 individual glycosylation sites are dispensable for the bioactivity and conformation of env products, it appears that such is not the case when the whole gp41 glycan cluster is removed.
Similar articles
-
C-terminal tail of human immunodeficiency virus gp41: functionally rich and structurally enigmatic.J Gen Virol. 2013 Jan;94(Pt 1):1-19. doi: 10.1099/vir.0.046508-0. Epub 2012 Oct 17. J Gen Virol. 2013. PMID: 23079381 Free PMC article. Review.
-
HIV-1 envelope glycoprotein biosynthesis, trafficking, and incorporation.J Mol Biol. 2011 Jul 22;410(4):582-608. doi: 10.1016/j.jmb.2011.04.042. J Mol Biol. 2011. PMID: 21762802 Free PMC article. Review.
-
Biological properties of recombinant HIV envelope synthesized in CHO glycosylation-mutant cell lines.Virology. 1996 Apr 1;218(1):224-31. doi: 10.1006/viro.1996.0182. Virology. 1996. PMID: 8615025
-
Role of HIV-1 envelope V3 loop cleavage in cell tropism.AIDS Res Hum Retroviruses. 1993 Oct;9(10):1007-15. doi: 10.1089/aid.1993.9.1007. AIDS Res Hum Retroviruses. 1993. PMID: 8280475
-
The glycosylation of human immunodeficiency virus type 1 transmembrane glycoprotein (gp41) is important for the efficient intracellular transport of the envelope precursor gp160.J Gen Virol. 1995 Jun;76 ( Pt 6):1509-14. doi: 10.1099/0022-1317-76-6-1509. J Gen Virol. 1995. PMID: 7782780
Cited by
-
Novel approaches to inhibit HIV entry.Viruses. 2012 Feb;4(2):309-24. doi: 10.3390/v4020309. Epub 2012 Feb 21. Viruses. 2012. PMID: 22470838 Free PMC article. Review.
-
Role of complex carbohydrates in human immunodeficiency virus type 1 infection and resistance to antibody neutralization.J Virol. 2010 Jun;84(11):5637-55. doi: 10.1128/JVI.00105-10. Epub 2010 Mar 24. J Virol. 2010. PMID: 20335257 Free PMC article.
-
Mapping of domains on HIV envelope protein mediating association with calnexin and protein-disulfide isomerase.J Biol Chem. 2010 Apr 30;285(18):13788-96. doi: 10.1074/jbc.M109.066670. Epub 2010 Mar 4. J Biol Chem. 2010. PMID: 20202930 Free PMC article.
-
Conserved positive selection signals in gp41 across multiple subtypes and difference in selection signals detectable in gp41 sequences sampled during acute and chronic HIV-1 subtype C infection.Virol J. 2008 Nov 24;5:141. doi: 10.1186/1743-422X-5-141. Virol J. 2008. PMID: 19025632 Free PMC article.
-
Conserved, N-linked carbohydrates of human immunodeficiency virus type 1 gp41 are largely dispensable for viral replication.J Virol. 2001 Dec;75(23):11426-36. doi: 10.1128/JVI.75.23.11426-11436.2001. J Virol. 2001. PMID: 11689624 Free PMC article.
References
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Research Materials