Liu Y, Yang N, Teng CT. COUP-TF acts as a competitive repressor for estrogen receptor-mediated activation of the mouse lactoferrin gene.
Mol Cell Biol 1993;
13:1836-46. [PMID:
8441416 PMCID:
PMC359496 DOI:
10.1128/mcb.13.3.1836-1846.1993]
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Abstract
We previously demonstrated that the estrogen response module (mERM) of the mouse lactoferrin gene, which contains an overlapping chicken ovalbumin upstream promoter transcription factor (COUP-TF)- and estrogen receptor-binding element, is responsible for estrogen induction. In this report we show that COUP-TF represses the mERM response to estrogen stimulation. Mutation and deletion of the COUP-TF-binding element or reduction of the endogenous COUP-TF increases mERM estrogen responsiveness. Likewise, overexpression of the COUP-TF expression vector blocked the estrogen-stimulated response of mERM in transfected cells. The molecular mechanism of this repression is due to the competition between COUP-TF and the estrogen receptor for binding at identical contact sites in the overlapping region of the mERM. Our results indicate that two members of the steroid-thyroid receptor superfamily work in concert to modulate lactoferrin gene expression.
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