Regulation of HIV-1 Gene Expression by the Transactivator Protein Tat

Abstract

The regulation of HIV-1 gene expression is an area of intense investigation. Like all retroviruses, HIV-1 integrates into cellular DNA, and its gene expression is dependent on host cell transcription factors and polymerases (Gaynor 1992). Cellular transcription factors are able to interact with distinct regulatory regions in the long terminal repeat to modulate gene expression (Gaynor 1992). In addition, viral-encoded proteins are critical to the control of HIV-1 gene expression. A number of important questions exist concerning the mechanisms which regulate HIV-1 gene expression. What cellular factors are responsible for increases in HIV-1 gene expression in response to T-lymphocyte activation? What are the mechanisms that repress HIV-1 gene expression in quiescent cells? How do HIV-1 transactivator proteins stimulate increases in gene expression? An understanding of these questions is critical to determining the interplay between viral and cellular factors which regulate HIV-1 gene expression.