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

The **Trans-activator of transcription protein (Tat)** is a small, arginine-rich regulatory protein encoded by the *tat* gene in HIV-1. It is an **essential viral factor** that drastically enhances the efficiency of viral transcription by binding to the trans-activation response element (TAR) on HIV-1 RNA and recruiting the host positive transcription elongation factor b (P-TEFb), composed of CDK9 and Cyclin T1, to phosphorylate RNA polymerase II. This activation stimulates efficient elongation and production of full-length viral RNA, enabling HIV replication and persistence[1][2][3][4]. Tat is also released extracellularly, where it is neurotoxic and immunosuppressive, contributing to HIV pathogenesis and complications such as HIV-associated neurocognitive disorders. As of 2025, Tat is considered a validated—but as yet not clinically targeted—therapeutic target for novel antivirals or neuroprotective agents[1][3][4].

Other names

Tat proteinHIV-1 Tat proteinTransactivator of transcription (Tat)HIV Tat

Inhibition of Tat binding to TAR RNA Blocking Tat-mediated recruitment of transcriptional machinery (P-TEFb, CDK9, Cyclin T1) Disruption of Tat translocation or secretion Inhibition of Tat-induced apoptosis or neurotoxicity