Previous Article | Next Article ![]()
J. Virol., 09 1996, 5777-5785, Vol 70, No. 9
P Beauparlant, H Kwon, M Clarke, R Lin, N Sonenberg, M Wainberg and J Hiscott
The human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR)
contains two binding sites for the NF-kappa B/Rel family of transcription
factors which are required for the transcriptional activation of viral
genes by inflammatory cytokines such as tumor necrosis factor alpha
(TNF-alpha) and interleukin-1. In the present study, we examined the effect
of transdominant mutants of I kappa B alpha on the synergistic activation
of the HIV-1 LTR by TNF-alpha and the HIV-1 transactivator, Tat, in Jurkat
T cells. The synergistic induction of HIV-1 LTR-driven gene expression
represented a 50- to 70- fold stimulation and required both an intact HIV-1
enhancer and Tat-TAR element interaction, since mutations in Tat protein
(R52Q, R53Q) or in the bulge region of the TAR element that eliminated Tat
binding to TAR were unable to stimulate LTR expression. Coexpression of I
kappa B alpha inhibited Tat-TNF-alpha activation of HIV LTR in a
dose-dependent manner. Transdominant forms of I kappa B alpha, mutated in
critical serine or threonine residues required for inducer-mediated (S32A,
S36A) and/or constitutive (S283A, T291A, T299A) phosphorylation of I kappa
B alpha were tested for their capacity to block HIV-1 LTR transactivation.
I kappa B alpha molecules mutated in the N-terminal sites were not degraded
following inducer-mediated stimulation (t1/2, > 4 h) and were able to
efficiently block HIV-1 LTR transactivation. Strikingly, the I kappa B
alpha (S32A, S36A) transdominant mutant was at least five times as
effective as wild-type I kappa B alpha in inhibiting synergistic induction
of the HIV-1 LTR. This mutant also effectively inhibited HIV-1
multiplication in a single-cycle infection model in Cos-1 cells, as
measured by Northern (RNA) blot analysis of viral mRNA species and viral
protein production. These experiments suggest a strategy that may
contribute to inhibition of HIV-1 gene expression by interfering with the
NF-kappa B/Rel signaling pathway.
Copyright © 1996, American Society for Microbiology
Transdominant mutants of I kappa B alpha block Tat-tumor necrosis factor synergistic activation of human immunodeficiency virus type 1 gene expression and virus multiplication
Lady Davis Institute for Medical Research, Montreal, Quebec, Canada.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|