N-terminal substitutions in HIV-1 gp41 reduce the expression of non-trimeric envelope glycoproteins on the virus.

TitleN-terminal substitutions in HIV-1 gp41 reduce the expression of non-trimeric envelope glycoproteins on the virus.
Publication TypeJournal Article
Year of Publication2008
AuthorsDey AK, David KB, Ray N, Ketas TJ, Klasse PJ, Doms RW, Moore JP
JournalVirology
Volume372
Issue1
Pagination187-200
Date Published2008 Mar 1
ISSN0042-6822
KeywordsAmino Acid Substitution, Cell Fusion, Cell Line, Dimerization, env Gene Products, Human Immunodeficiency Virus, Gene Expression Regulation, Viral, HeLa Cells, HIV Envelope Protein gp160, HIV Envelope Protein gp41, HIV-1, Humans, Virion
Abstract

The native, functional HIV-1 envelope glycoprotein (Env) complex is a trimer of two non-covalently associated subunits: the gp120 surface glycoprotein and the gp41 transmembrane glycoprotein. However, various non-functional forms of Env are present on virus particles and HIV-1-infected cells, some of which probably arise as the native complex decays. The aberrant forms include gp120-gp41 monomers and oligomers, as well as gp41 subunits from which gp120 has dissociated. The presence of non-functional Env creates binding sites for antibodies that do not recognize native Env complexes and that are, therefore, non-neutralizing. Non-native Env forms (monomers, dimers, tetramers and aggregates) can also arise when soluble gp140 proteins, lacking the cytoplasmic and transmembrane domains of gp41, are expressed for vaccine studies. We recently identified five amino acids in the gp41 N-terminal region (I535, Q543, S553, K567 and R588) that promote gp140 trimerization. We have now studied their influence on the function and antigenic properties of JR-FL Env expressed on the surfaces of pseudoviruses and Env-transfected cells. The 5 substitutions in gp41 reduce the expression of non-trimeric gp160s, without affecting trimer levels. Pseudovirions bearing the mutant Env are fully infectious with similar kinetics of Env-mediated fusion. Various non-neutralizing antibodies bind less strongly to the Env mutant, but neutralizing antibody binding is unaffected. Hence the gp41 substitutions do not adversely affect Env structure, supporting their use for making new Env-based vaccines. The mutant Env might also help in studies intended to correlate antibody binding to virus neutralization. Of note is that the 5 residues are much more frequent, individually or collectively, in viruses from subtypes other than B.

DOI10.1016/j.virol.2007.10.018
Alternate JournalVirology
PubMed ID18031785
PubMed Central IDPMC2317825
Grant ListAI 30030 / AI / NIAID NIH HHS / United States
AI 36082 / AI / NIAID NIH HHS / United States
AI 45463 / AI / NIAID NIH HHS / United States
R01 AI045463 / AI / NIAID NIH HHS / United States
R01 AI045463-01 / AI / NIAID NIH HHS / United States
R01 AI045463-02 / AI / NIAID NIH HHS / United States
R01 AI045463-03 / AI / NIAID NIH HHS / United States
R01 AI045463-04 / AI / NIAID NIH HHS / United States
R01 AI045463-05 / AI / NIAID NIH HHS / United States
R01 AI045463-06 / AI / NIAID NIH HHS / United States
R01 AI045463-07 / AI / NIAID NIH HHS / United States
R01 AI045463-08 / AI / NIAID NIH HHS / United States
R01 AI045463-09 / AI / NIAID NIH HHS / United States
R01 AI045463-10 / AI / NIAID NIH HHS / United States
R37 AI036082 / AI / NIAID NIH HHS / United States
R37 AI036082-06 / AI / NIAID NIH HHS / United States
R37 AI036082-07 / AI / NIAID NIH HHS / United States
R37 AI036082-08 / AI / NIAID NIH HHS / United States
R37 AI036082-09 / AI / NIAID NIH HHS / United States
R37 AI036082-10 / AI / NIAID NIH HHS / United States
R37 AI036082-11 / AI / NIAID NIH HHS / United States
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R37 AI036082-13 / AI / NIAID NIH HHS / United States
R37 AI036082-14 / AI / NIAID NIH HHS / United States
R37 AI036082-15 / AI / NIAID NIH HHS / United States

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