Corepressor subnuclear organization is regulated by estrogen receptor via a mechanism that requires the DNA-binding domain

Mol Cell Endocrinol. 2005 Feb 28;231(1-2):33-47. doi: 10.1016/j.mce.2004.12.003.

Abstract

The restriction of transcription factors to certain domains within the cell nucleus must serve an important regulatory function. The silencing mediator of retinoic acid and thyroid hormone (SMRT) and other members of the corepressor complex are enriched in spherical intranuclear foci, and repress estrogen receptor alpha (ERalpha)-dependent transcriptional activity. When fluorescent protein (FP)-labeled SMRT and ERalpha were co-expressed, the proteins co-localized. The subnuclear organization and positioning of the complexes, however, depended on the ligand state of the receptor. Automated image analysis was used to quantify the ERalpha-dependent change in SMRT organization in randomly selected living cell populations. The results demonstrate that the subnuclear positioning of SMRT is influenced by the ligand-bound ERalpha, and this activity is dependent on the ratio of the co-expressed ERalpha and SMRT. A deletion mutant of ERalpha showed that the receptor DNA-binding domain was necessary for the ligand-dependent positioning of SMRT. These results define important organizational mechanisms that underlie nuclear receptor regulation of gene expression.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • Cell Line
  • DNA / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Estrogen Receptor alpha / chemistry
  • Estrogen Receptor alpha / genetics
  • Estrogen Receptor alpha / physiology*
  • Gene Expression Regulation
  • Humans
  • Image Interpretation, Computer-Assisted
  • Intranuclear Space / chemistry
  • Intranuclear Space / ultrastructure*
  • Luminescent Proteins
  • Mice
  • Nuclear Receptor Co-Repressor 2
  • Recombinant Fusion Proteins
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Transfection

Substances

  • DNA-Binding Proteins
  • Estrogen Receptor alpha
  • Luminescent Proteins
  • NCOR2 protein, human
  • Ncor2 protein, mouse
  • Nuclear Receptor Co-Repressor 2
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • DNA