HIV Tat, its TARgets and the control of viral gene expression

The human immunodeficiency virus (HIV-1) (transactivator of transcription (Tat)) protein is a pleiotropic factor that induces a broad range of biological effects in numerous cell types. At the HIV promoter, Tat is a powerful transactivator of gene expression, which acts by both inducing chromatin remodeling and by recruiting elongation-competent transcriptional complexes onto the viral LTR. Besides these transcriptional activities. Tat is released outside the cells and interacts with different cell membrane-associated receptors. Finally, extracellular Tat can be internalized by cells through an active endocytosis process. Here we discuss some of the molecular mechanisms involved in intracellular and extracellular Tat function. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.