Trans-activator of transcription protein (HIV-1) (HIV-1 Tat)

The trans-activator of transcription protein (HIV-1), commonly called Tat, is an essential and unique regulatory protein encoded by the HIV-1 virus[1][2][3][5][7]. Tat is a small, intrinsically disordered RNA-binding protein (86–102 amino acids) produced early in the HIV life cycle[3][7]. Its principal role is to activate HIV-1 gene expression by binding to the trans-activation response (TAR) RNA element at the 5' end of nascent HIV transcripts, dramatically increasing transcriptional efficiency by recruiting the host positive transcription elongation factor b (P-TEFb, cyclin T1/CDK9 complex) and facilitating efficient elongation by RNA polymerase II[1][5][6][8][9]. Tat also modulates cellular gene expression, alters immune cell function, and is secreted from infected cells, where it can affect uninfected bystander cells, contributing to HIV pathogenesis and neurotoxicity[2][5][7]. Due to its central role in viral replication and disease progression, Tat is a validated but challenging target for anti-HIV therapy design; current clinical antiretrovirals do not specifically inhibit Tat, but novel inhibitors that disrupt Tat-TAR or Tat-P-TEFb interaction are under investigation[6][8]. Targeting Tat faces challenges from its rapid mutation rate, multifunctionality, and the risk of affecting host transcription factors[2][5][7].

Other names

TatHIV TatHIV-1 trans-activator of transcription

Inhibition of Tat-TAR RNA interaction (investigational) - Disruption of Tat interaction with P-TEFb (cyclin T1 and CDK9) (investigational)