A negative regulatory element within the proximal promoter region of the rat ornithine decarboxylase gene

Biwei Zhao, Addanki P. Kumar, Andrew P. Butler

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

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 ur treated 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.

Original languageEnglish (US)
Pages (from-to)212-218
Number of pages7
JournalMolecular Carcinogenesis
Volume29
Issue number4
DOIs
StatePublished - 2000
Externally publishedYes

Keywords

  • Ets transcription factor
  • Negative regulatory element
  • Ornithine decarboxylase
  • Phorbol ester

ASJC Scopus subject areas

  • Molecular Biology
  • Cancer Research

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