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cisExpression of the F12 Human Immunodeficiency Virus (HIV) Nef Allele Transforms the Highly Productive NL4-3 HIV Type 1 to a Replication-Defective Strain: Involvement of both Env gp41 and CD4 Intracytoplasmic Tails

Authors :
Olivetta, Eleonora
Pugliese, Katherina
Bona, Roberta
D'Aloja, Paola
Ferrantelli, Flavia
Santarcangelo, Anna Claudia
Mattia, Gianfranco
Verani, Paola
Federico, Maurizio
Source :
The Journal of Virology; January 2000, Vol. 74 Issue: 1 p483-492, 10p
Publication Year :
2000

Abstract

ABSTRACTF12 human immunodeficiency virus type 1 (HIV-1) nefis a naturally occurring nefmutant cloned from the provirus of a nonproductive, nondefective, and interfering HIV-1 variant (F12-HIV). We have already shown that cells stably transfected with a vector expressing the F12-HIV nefallele do not downregulate CD4 receptors and, more peculiarly, become resistant to the replication of wild type (wt) HIV. In order to investigate the mechanism of action of such an HIV inhibition, the F12-HIVnefgene was expressed in the context of the NL4-3 HIV-1 infectious molecular clone by replacing the wt nefgene (NL4-3/chi). Through this experimental approach we established the following. First, NL4-3/chi and nef-defective (?nef) NL4-3 viral particles behave very similarly in terms of viral entry and HIV protein production during the first replicative cycle. Second, no viral particles were produced from cells infected with NL4-3/chi virions, whatever the multiplicity of infection used. The viral inhibition apparently occurs at level of viral assembling and/or release. Third, this block could not be relieved by in-transexpression of wt nef. Finally, NL4-3/chi reverts to a producer HIV strain when F12-HIV Nef is deprived of its myristoyl residue. Through a CD4 downregulation competition assay, we demonstrated that F12-HIV Nef protein potently inhibits the CD4 downregulation induced by wt Nef. Moreover, we observed a redistribution of CD4 receptors at the cell margin induced by F12-HIV Nef. These observations strongly suggest that F12-HIV Nef maintains the ability to interact with the intracytoplasmic tail of the CD4 receptor molecule. Remarkably, we distinguished the intracytoplasmic tails of Env gp41 and CD4 as, respectively, viral and cellular targets of the F12-HIV Nef-induced viral retention. For the first time, the inhibition of the viral life cycle by means of in-cisexpression of a Nef mutant is here reported. Delineation of the F12-HIV Nef mechanism of action may offer additional approaches to interference with the propagation of HIV infection.

Details

Language :
English
ISSN :
0022538X and 10985514
Volume :
74
Issue :
1
Database :
Supplemental Index
Journal :
The Journal of Virology
Publication Type :
Periodical
Accession number :
ejs57758865
Full Text :
https://doi.org/10.1128/JVI.74.1.483-492.2000