Trans-activation response element (TAR)
The HIV trans-activation response element is an RNA element which is known to be required for the trans-activation of the viral promoter and for virus replication. The TAR hairpin is a dynamic structure that acts as a binding site for the Tat protein, and this interaction stimulates the activity of the long terminal repeat promoter.
Further analysis has shown that TAR is a pre-microRNA that produces mature microRNAs from both strands of the TAR stem-loop.
These miRNAs are thought to prevent infected cells from undergoing apoptosis by downregulating the genes ERCC1, IER3, CDK9, and Bim.
