The

HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...

trans-activation response (TAR) 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 Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

by downregulating the genes ERCC1,

IER3 Radiation-inducible immediate-early gene IEX-1 is a protein that in humans is encoded by the ''IER3'' gene. This gene functions in the protection of cells from Fas- or tumor necrosis factor type alpha-induced apoptosis Apoptosis (from grc, ...

, CDK9, and

Bim ''Bim'' is a 1974 Trinidad and Tobago film written by Raoul Pantin and directed by Hugh A. Robertson. It was described by Bruce Paddington as "one of the most important films to be produced in Trinidad and Tobago and... one of the classics of Ca ...

. Human polyomavirus 2 (

JC virus ''Human polyomavirus 2'', commonly referred to as the JC virus or John Cunningham virus, is a type of human polyomavirus (formerly known as papovavirus). It was identified by electron microscopy in 1965 by ZuRhein and Chou, and by Silverman and ...

) contains a TAR-homologous sequence in its late promoter that is responsive to HIV-1 derived Tat.

References

External links

*
miRBase page for hiv1-mir-TAR
MicroRNA Cis-regulatory RNA elements {{molecular-cell-biology-stub