Cell cycle regulation of human interleukin-8 gene expression by the human immunodeficiency virus type 1 Tat protein

R. Mahieux, P. F. Lambert, E. Agbottah, M. A. Halanski, L. Deng, F. Kashanchi, J. N. Brady

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

The human immunodeficiency virus type 1 (HIV-1) Tat protein has been reported to transactivate several cellular genes, including the potent chemotactic factor interleukin-8 (IL-8). Consistent with these in vitro assays, elevated levels of IL-8 protein are found in the serum of HIV-infected individuals. We now extend these observations by demonstrating that Tat induction of IL-8 is linked to the cell cycle. Cells that constitutively express the Tat(1-86) protein (eTat) and control cells (pCEP) were reversibly blocked at the G1/S border with hydroxyurea or thymidine. The cells were subsequently released, and IL-8 expression was monitored by RNase protection assays and enzyme-linked immunosorbent assay (ELISA). RNase protection assays demonstrated that IL-8 mRNA expression is transiently induced, approximately fourfold, as the Tat-expressing cells enter S phase. Consistent with the RNase protection assay, an increase in IL-8 protein was observed in the cell supernatant using an IL-8 ELISA. Similar experiments were performed following a reversible block at the G2/M border with nocodazole and release into G1. Using the RNase protection assay and ELISA, little or no increase in IL-8 expression was observed during G1. Using gel shift as well as an immobilized DNA binding assay, we demonstrate that the increase in IL-8 gene expression correlates with a specific increase in p65 NF-κB binding activity only in the nucleus of the Tat-expressing cells. Moreover, the CREB-binding protein coactivator is present in the complex in the Tat cell line. Finally, we demonstrate that the presence of the proteasome inhibitor MG-132 inhibits the induction of NF-κB binding, as well as IL-8 expression, supporting the role of NF-κB.

Original languageEnglish (US)
Pages (from-to)1736-1743
Number of pages8
JournalJournal of virology
Volume75
Issue number4
DOIs
StatePublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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