functional and physical consequence of human immunodefficiency virus transactivator tat interaction with human cell cycle regulator p53

human immunodeficiency virus (hiv) transactivator tat is a potent activator of both viral and cellu lar genes. tat has also been implicated in the development of aids-related malignancy. here, we show that tat physically and functionally is able to sequester the cell cycle check point protein p53. this sequestration results in non-functional promoter activity of cyclin-dependent kinase/cyclin in hibitor, namely p21 (waf1). therefore, it is proposed that a tat/p53 complex in vivo may deregulate p53 responsive genes, hence allowing for deregulation of check point, which may lead to development of malignancies.