HIV Tat protein (None)

The HIV Tat protein (Trans-Activator of Transcription) is a small, basic regulatory protein encoded by the human immunodeficiency virus type 1 (HIV-1). It is essential for efficient transcription of the integrated HIV proviral DNA, acting as a potent transactivator that dramatically increases transcription from the viral long terminal repeat (LTR) promoter. Tat binds specifically to the TAR RNA element and recruits host cellular factors, most notably P-TEFb, to stalled RNA polymerase II complexes at the LTR promoter, leading to increased production of full-length viral transcripts. Beyond its role in activating viral gene expression, Tat modulates leukocyte activation/proliferation and can be released extracellularly, contributing to immune dysfunctions and neurotoxicity associated with AIDS progression. It is considered a potential target for antiretroviral therapy development and latency-reversing agents.

Binds to TAR RNA and recruits P-TEFb to activate RNA polymerase II elongation.