       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).

