Long-range activation of GREB1 by estrogen receptor via three distal consensus estrogen-responsive elements in breast cancer cells

Mol Endocrinol. 2007 Nov;21(11):2651-62. doi: 10.1210/me.2007-0082. Epub 2007 Jul 31.

Abstract

The estrogen receptor (ER) binds to estrogen-responsive elements (EREs) to activate gene transcription. The best characterized EREs are located in proximal gene promoters, but recent data indicate that only a minority of ER binding sites lie within proximal promoter regions. GREB1 (gene regulated by estrogen in breast cancer 1) is an ER target gene that regulates estrogen-induced proliferation in breast cancer cells. We identified three consensus EREs, located at -21.2, -9.5, and -1.6 kb upstream of the closest GREB1a transcription start site that appear to mediate long-range GREB1 gene activation by ER. All three ERE sites nucleate ER, steroid receptor coactivator-3 (SRC-3), and RNA polymerase II (Pol II) and undergo histone acetylation in response to estradiol. Estrogen-stimulated ER binding at all three EREs was cyclic and synchronous. SRC-3 and Pol II recruitment to all three EREs was activated by estrogen but not tamoxifen. In contrast, estrogen stimulated only Pol II and not ER or SRC-3 recruitment to the GREB1 core promoter regions. Long-range histone acetylation, centered on the three ERE motifs and the GREB1 core promoters, was observed in response to estrogen but not to tamoxifen. These data suggest that estrogen-stimulated GREB1 transcription may involve coordinated ER binding to all three distal consensus ERE motifs. Long-range activation by ER acting at multiple EREs may be more common than previously appreciated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Base Sequence
  • Breast Neoplasms / metabolism*
  • Cell Line, Tumor
  • Enzyme Activation
  • Estradiol / metabolism
  • Estrogens / metabolism
  • Histone Acetyltransferases / metabolism
  • Humans
  • Molecular Sequence Data
  • Neoplasm Proteins / metabolism*
  • Neoplasm Proteins / physiology*
  • Nuclear Receptor Coactivator 3
  • Promoter Regions, Genetic
  • Receptors, Estrogen / metabolism
  • Tamoxifen / pharmacology
  • Trans-Activators / metabolism
  • Transcription, Genetic

Substances

  • Estrogens
  • GREB1 protein, human
  • Neoplasm Proteins
  • Receptors, Estrogen
  • Trans-Activators
  • Tamoxifen
  • Estradiol
  • Histone Acetyltransferases
  • NCOA3 protein, human
  • Nuclear Receptor Coactivator 3