CCAAT/enhancer-binding proteins. A role in regulation of human involucrin promoter response to phorbol ester.
The phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) is a potent inducer of keratinocyte differentiation and of involucrin gene expression. In the present study we show that a CCAAT/enhancer-binding protein (C/EBP) site in the proximal regulatory region is required for the phorbol ester response. Mutation of the C/EBP site results in the loss of basal and TPA-responsive activity. Gel mobility supershift analysis shows that C/EBPalpha binding to this site is increased by TPA treatment. Moreover, cotransfection of the human involucrin reporter plasmid with C/EBPalpha increases promoter activity to an extent comparable with TPA treatment. Mutation of the C/EBP-binding site eliminates these responses. Transfection experiments using GADD153 to create C/EBP-null conditions confirm that C/EBP factors are absolutely required for promoter activity and TPA responsiveness. C/EBPbeta and C/EBPdelta inhibit both TPA- and C/EBPalpha-dependent promoter activation, indicating functional differences among C/EBP family members. These results suggest that C/EBP transcription factor activity is necessary for basal promoter activity and TPA response of the involucrin gene.
Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4970, USA.
C
C
Agarwal
T
T
Efimova
J F
JF
Welter
J F
JF
Crish
R L
RL
Eckert
D022762:CCAAT-Enhancer-Binding Proteins; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011498:Protein Precursors; C032253:involucrin; D013755:Tetradecanoylphorbol Acetate