Pj. Reddig et al., LOCALIZATION OF THE 12-O-TETRADECANOYLPHORBOL-13-ACETATE RESPONSE OF THE HUMAN ORNITHINE DECARBOXYLASE PROMOTER TO THE TATA BOX, Molecular carcinogenesis, 17(2), 1996, pp. 92-104
In a previous study, we narrowed the region of the human ornithine dec
arboxylase (ODC) promoter responsive to 12-O-tetradecanoylphorbol-13-a
cetate (TPA) to nt -42 to +54 around the transcription initiation site
(Kim YJ, Pan H, Verma AK, Mol Carcinog 10:169-179, 1994). Here we rep
ort defining the role of the TATA box in TPA-induced transcription fro
m the -42/+54 ODC promoter fragment. A transversion mutation at the th
ird position of the TATA box (<TA(T)under bar AAGT>--><TA(A)under bar
AAGT>) reduced TPA responsiveness of the reporter construct -42/+54 OD
C-Luc by 49%. Electrophoretic mobility shift assays (EMSAs) using HeLa
cell nuclear protein extracts revealed no differences in the binding
pattern between the natural -42/+54 ODC promoter element and the -42/54 ODC promoter element containing the T-->A mutation. However, antibo
dies to the general transcription factor TFIIB disrupted the DNA-prote
in complexes normally formed with the -42/+54 ODC promoter element in
EMSAs. A consensus TATA box oligonucleotide formed two bands, with the
faster mobility band displaying enhanced binding with nuclear protein
extracts from TPA treated cells. Furthermore, incubation of HeLa cell
nuclear extracts with an oligonucleotide containing the ODC TATA box
also caused formation of two specific bands in EMSA. Both bands exhibi
ted augmented binding to nuclear proteins from TPA-treated cells. Intr
oduction of the T-->A transversion mutation in the ODC TATA oligonucle
otide eliminated binding of the faster migrating band formed with the
natural ODC TATA oligonucleotide. These results indicate that TPA modu
lation of the general transcription machinery may play a role in the T
PA-activated transcription of the human ODC promoter. (C) 1996 Wiley-L
iss, Inc.