Trans-activation response RNA element (TAR RNA element)

The **Trans-activation response RNA element** (TAR RNA element) is a highly conserved, structured RNA stem-loop found at the 5' end of all HIV-1 transcripts, comprising the first ~60 nucleotides of the genome[3][7][1][5]. It functions as a platform for the recruitment of the viral Tat protein, which in turn assembles the transcriptional elongation complex (P-TEFb) needed for productive transcription of the HIV genome[6][2][5]. The TAR region exhibits multiple stem-loop structures, critical bulge and loop motifs for Tat binding, and dynamic conformational mobility influencing viral replication, RNA packaging, and gene regulation[1][3][8]. TAR also serves as a substrate for Dicer, producing viral miRNAs that modulate host cell survival and immune evasion[5][9]. Its central role in HIV-1 transcription, replication, and pathogenesis—and the fact that it is not a human gene product but a virus-encoded non-coding RNA—has made TAR RNA a prominent target for novel antiviral drug development and functional studies into viral latency, immune modulation, and apoptosis[4][1].

Other names

HIV TAR RNAHIV-1 TAR RNATrans-activation response (TAR) elementTAR

Inhibition of Tat-TAR interaction (blocks transcriptional activation and viral replication) Binding to TAR bulge site to prevent recruitment of co-factors essential for transcription Modulation of TAR structure to disrupt RNA-protein interactions