Abstract
The long terminal repeat (LTR) of the human immunodeficiency virus (HIV) contains three binding sites for the transcriptional factor Sp1. In order to investigate the role that the Sp1-binding sites play in regulation of H1V replication, we have introduced a deletion of all three Sp1-binding sites into the LTR of an infectious molecular clone of HIV. Viral stocks have been prepared from this mutant virus, designated dl-Sp, and these stocks have been used to study its replicative ability in human T cells. The dl-Sp virus replicated efficiently in MT4 cells and in phytohemagglutinin-stimulated human peripheral blood lymphocytes, but it replicated poorly and with delayed kinetics in A3.01 (CEM) T cells unless those cells had been treated with the cytokine tumor necrosis factor α. Gel retardation assays to study the levels of DNA-binding proteins present in these cells showed that NF-κB activity could he detected in the nuclei of MT4 cells hut not in A3.01 cells unless they had heen treated with tumor necrosis factor α. Thus, the presence of NF-κB activity appeared to be required for efficient replication of an HIV whose LTR Sp1-binding sites had been deleted. This suggests that NF-κB can functionally compensate for Sp1 in activating HIV replication. The HIV LTR is therefore similar to the promoter-enhancer units of other viruses in that it is composed of multiple functional elements that may contrihute differently to viral replication depending on the levels of DNA-binding proteins present in the target cells.
Original language | English (US) |
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Pages (from-to) | 1414-1419 |
Number of pages | 6 |
Journal | Journal of virology |
Volume | 65 |
Issue number | 3 |
DOIs | |
State | Published - 1991 |
Externally published | Yes |
ASJC Scopus subject areas
- Microbiology
- Immunology
- Insect Science
- Virology