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1996-02-27
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Document 0475
DOCN M9630475
TI Activation of human immunodeficiency virus gene expression by
ultraviolet light in stably transfected human cells does not require the
enhancer element.
DT 9603
AU Valerie K; Singhal A; Kirkham JC; Laster WS; Rosenberg M; Department of
Radiation Oncology, Massey Cancer Center, Medical; College of Virginia,
Virginia Commonwealth University, Richmond; 23298-0058, USA.
SO Biochemistry. 1995 Dec 5;34(48):15760-7. Unique Identifier : AIDSLINE
MED/96097002
AB Ultraviolet light (UV) exposure of cells infected with human
immunodeficiency virus type I (HIV) or transfected with HIV reporter
genes increases virus-directed gene expression. Here we report the
mapping of the UV response on the long terminal repeat (LTR) by using
human cells stably transfected with HIV promoter plasmids harboring
different mutations and controlling the expression of the
chloramphenicol acetyltransferase (cat) reporter gene. Promoter mutation
analysis revealed that no specific upstream region of the LTR was
associated with UV activation, although a significant decrease was
observed with mutations in the basal promoter elements Spl and TATA.
Most importantly, UV activation was not diminished by removal of the -
119 to -69 region encompassing the LTR enhancer region or, more
specifically, by point mutations in the NF -kappa B binding elements.
Consistent with this result, we found that the phorbol ester (PMA)
response, which is known to act through the enhancer, occurred
independently and was synergistic with the UV response. Removal of the
-119 to -69 region did not affect UV activation; however, it resulted in
total abrogation of the PMA response. These results suggest that UV
activation is distinct from NF kappa B activation and does not act
through the enhancer in stably transfected cells. This is in dramatic
contrast to what is found with transient expression analysis of these
responses. Lastly, RNA protection experiments revealed that UV may act
on preassembled basal transcription complexes by allowing elongation of
nascent short mRNAs generated from the LTR.(ABSTRACT TRUNCATED AT 250
WORDS)
DE Chromatin Clone Cells *Enhancer Elements (Genetics) Gene Expression
Regulation, Viral/*RADIATION EFFECTS Hela Cells Human HIV Long
Terminal Repeat HIV-1/GENETICS/*RADIATION EFFECTS Plasmids Promoter
Regions (Genetics) Support, U.S. Gov't, P.H.S. Tetradecanoylphorbol
Acetate/PHARMACOLOGY Trans-Activation (Genetics)/DRUG EFFECTS/RADIATION
EFFECTS Transfection Ultraviolet Rays JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).