T-cell activation leads to poor activation of the HIV-1 clade E long terminal repeat and weak association of nuclear factor-κB and NFAT with its enhancer region

Anne Marie Lemieux, Marie Ève Paré, Brigitte Audet, Éric Legault, Sylvain Lefort, Nancy Boucher, Sébastien Landry, Tim Van Opijnen, Ben Berkhout, Mojgan H. Naghavi, Michel J. Tremblay, Benoit Barbeau*

*Corresponding author for this work

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

The enhancer region in the human immunodeficiency virus type 1 (HIV-1) 5′-long terminal repeat (LTR) is very important for viral transcription. This promoter sequence binds both nuclear factor-κB and NFAT, two important modulators of HIV-1 gene expression. Previous studies have indicated that the enhancer regions of the different HIV-1 clade LTRs differ in their number of NF-κB-binding sites. In this study, we have compared the activation potential of the different HIV-1 clade and HIV-2 LTRs and assessed their interaction with NFAT and NF-κB. In T-cell lines and primary CD4+ T-cells, the results showed that the HIV-1 clade E LTR (with a single NF-κB-binding site) was the weakest LTR regardless of the tested activators, whereas the HIV-2 LTR was the most responsive LTR. The clade E enhancer region was also demonstrated to be the weakest enhancer region in transfection experiments with luciferase reporter-based vectors. Electrophoretic mobility shift assays with extracts from activated CD4+ T-cells indicated that, although NF-κB and NFAT bound all enhancers, HIV-1 clade E and HIV-2 LTR enhancers were poor binding targets for these two factors. Weak NFAT binding to clade E enhancers was also confirmed using NFAT1-expressing 293T cells in competition experiments. We have also shown the absence of interaction of NF-κB or NFAT with the third NF-κB repeat present in clade C. However, the clade C enhancer bound NFAT more efficiently than all other enhancer regions tested. Our results hence demonstrate for the first time that differences in the binding of NF-κB and NFAT to the enhancer regions could be responsible for some of the observed variation in HIV-1 clade LTR activation, whereas HIV-2 LTR activation seems mostly independent of these interactions.

Original languageEnglish (US)
Pages (from-to)52949-52960
Number of pages12
JournalJournal of Biological Chemistry
Volume279
Issue number51
DOIs
StatePublished - Dec 17 2004

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Lemieux, A. M., Paré, M. È., Audet, B., Legault, É., Lefort, S., Boucher, N., Landry, S., Van Opijnen, T., Berkhout, B., Naghavi, M. H., Tremblay, M. J., & Barbeau, B. (2004). T-cell activation leads to poor activation of the HIV-1 clade E long terminal repeat and weak association of nuclear factor-κB and NFAT with its enhancer region. Journal of Biological Chemistry, 279(51), 52949-52960. https://doi.org/10.1074/jbc.M409896200