The
HIV 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
A hairpin or hair pin is a long device used to hold a person's hair in place. It may be used simply to secure long hair out of the way for convenience or as part of an elaborate hairstyle or coiffure. The earliest evidence for dressing the hai ...
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
A long terminal repeat (LTR) is a pair of identical sequences of DNA, several hundred base pairs long, which occur in eukaryotic genomes on either end of a series of genes or pseudogenes that form a retrotransposon or an endogenous retrovirus or ...
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 in ...
by
downregulating the genes
ERCC1,
IER3,
CDK9
Cyclin-dependent kinase 9 or CDK9 is a cyclin-dependent kinase associated with P-TEFb.
Function
The protein encoded by this gene is a member of the cyclin-dependent kinase (CDK) family. CDK family members are highly similar to the gene produc ...
, 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 ...
.
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 an ...
) 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
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