Nucleic Acids Research, Vol 25, Issue 3 496-502, Copyright © 1997 by Oxford University Press
K Verhoef, M Tijms and B Berkhout
HIV-1 transcription from the LTR promoter is activated by the viral Tat
protein through interaction with the nascent TAR RNA hairpin structure. The
mechanism of Tat-mediated transcriptional activation has been extensively
investigated with LTR-CAT reporter genes in transient transfections and,
more recently, in infection experiments with mutant HIV-1 variants. Several
discrepancies between these two assay systems have been reported. For
instance, whereas opening of the lower part of the TAR RNA stem does not
affect the promoter activity of an LTR-CAT plasmid in transient assays, the
corresponding virus mutant is fully replication-impaired. With the aim to
resolve this controversy, we have examined the activity of a set of TAR RNA
mutants in transient transfection experiments with a variety of cell types.
We now demonstrate that truncated TAR motifs exhibit a severe, but
cell-type dependent transcription defect. Whereas full LTR activity is
measured in COS cells that have been used regularly in previous
transfection assays, a severe defect is apparent in a variety of human cell
lines, including T cell lines that are typically used in HIV-1 replication
studies. These results suggest the presence of a human protein that
participates in Tat-mediated transcriptional activation through binding to
the lower part of the TAR stem. Several candidate co-factors have been
reported in literature. This study resolves the discrepancy between
transfection and infection studies on the requirements of the lower TAR
stem structure. The evidence also implies that LTR transcription studies
should be performed preferentially in human cell types.
ARTICLES
Optimal Tat-mediated activation of the HIV-1 LTR promoter requires a full-length TAR RNA hairpin
Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Dow-Tien, T. Yuan-Jhih, and L. Alan Creating a ribonuclease T-tat that preferentially recognizes and hydrolyzes HIV-1 TAR RNA in vitro and in vivo Nucleic Acids Res., February 11, 2008; 36(3): 963 - 969. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Apolloni, C. W. Hooker, J. Mak, and D. Harrich Human Immunodeficiency Virus Type 1 Protease Regulation of Tat Activity Is Essential for Efficient Reverse Transcription and Replication J. Virol., September 15, 2003; 77(18): 9912 - 9921. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. E. Garber, T. P. Mayall, E. M. Suess, J. Meisenhelder, N. E. Thompson, and K. A. Jones CDK9 Autophosphorylation Regulates High-Affinity Binding of the Human Immunodeficiency Virus Type 1 Tat-P-TEFb Complex to TAR RNA Mol. Cell. Biol., September 15, 2000; 20(18): 6958 - 6969. [Abstract] [Full Text]
|
|
|
|
|
|
A. T. Das, B. Klaver, and B. Berkhout The 5' and 3' TAR Elements of Human Immunodeficiency Virus Exert Effects at Several Points in the Virus Life Cycle J. Virol., November 1, 1998; 72(11): 9217 - 9223. [Abstract] [Full Text] [PDF]
|
|