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A negative regulatory element within the proximal promoter region of the rat ornithine decarboxylase gene
Author(s) -
Zhao Biwei,
Kumar Addanki P.,
Butler Andrew P.
Publication year - 2000
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/1098-2744(200012)29:4<212::aid-mc1003>3.0.co;2-0
Subject(s) - biology , ornithine decarboxylase , gene , ornithine decarboxylase antizyme , element (criminal law) , regulatory sequence , genetics , promoter , response element , regulation of gene expression , microbiology and biotechnology , gene expression , enzyme , biochemistry , political science , law
A putative Ets site with a core of GGAA located at nt −88 to −85 of the rat ornithine decarboxylase ( ODC ) gene was characterized by site‐directed mutagenesis and transient expression assays. Mutation of this site, when in pODClux2m, which contains a cluster of four Sp1‐binding sites, resulted in a 2.6‐fold increase in basal promoter activity in untreated cells, whereas the ratio of activity in 12‐ O ‐tetradecanoylphorbol‐13‐acetate (TPA)–treated cells relative to the ratio in untreated cells (the induction ratio) remained largely unchanged. However, when the mutation was in pODClux168, which contains only a single Sp1‐binding site (GC box V), it caused little alteration to either basal promoter activity or TPA induction ratio. A protein of 55–60 kDa was found specifically bound to this site, as shown by ultraviolet cross‐linking assay. In competition assay and methylation interference assay, this protein was shown to occupy the GGAA core, although it showed no antigenic relation to c‐Ets‐1 in an supershift assay. We suggest that this protein binds specifically to the GGAA core and functions to inhibit activation of the ODC promoter by distal elements, including the upstream Sp1 sites. Mol. Carcinog. 29:212–218, 2000. © 2000 Wiley‐Liss, Inc.