Human immunodeficiency virus type 1 trans-activation response element RNA (HIV-1 TAR RNA)

Human immunodeficiency virus type 1 trans-activation response element (TAR) RNA is a 59-nucleotide stem-loop structure located at the 5' end of all nascent HIV-1 transcripts (Karn & Stoltzfus, 2012). It serves as the essential binding site for the viral trans-activator protein (Tat), which is required for high-level viral gene expression (Bannwarth & Gatignol, 2005). The interaction between Tat and TAR recruits the host cellular positive transcription elongation factor b (P-TEFb) to the viral promoter, facilitating the phosphorylation of RNA polymerase II and ensuring efficient transcription elongation (Wei et al., 1998). In the absence of this interaction, the polymerase complex fails to process through the viral genome, leading to truncated transcripts and a halt in viral replication (Mousseau & Valente, 2012). Because TAR RNA is highly conserved and critical for the viral life cycle, it is a major target for the development of novel antiretroviral drugs (Abulwerdi & Al-Hashimi, 2012). Current therapeutic strategies include the use of small molecules, peptides, and antisense oligonucleotides designed to disrupt the Tat-TAR complex and inhibit viral production (Chavali et al., 2015).

Other names

TAR elementTrans-activation response elementHIV-1 TARTAR RNAHIV-1 trans-acting responsive element

Inhibition of the interaction between the viral Tat protein and the TAR RNA element, thereby preventing the recruitment of the host P-TEFb complex and blocking efficient viral transcription elongation.