TR4 orphan nuclear receptor functions as an apoptosis modulator via regulation of Bcl-2 gene expression

Biochem Biophys Res Commun. 2007 Sep 21;361(2):323-8. doi: 10.1016/j.bbrc.2007.06.168. Epub 2007 Jul 10.

Abstract

While Bcl-2 plays an important role in cell apoptosis, its relationship to the orphan nuclear receptors remains unclear. Here we report that mouse embryonic fibroblast (MEF) cells prepared from TR4-deficient (TR4(-/-)) mice are more susceptible to UV-irradiation mediated apoptosis compared to TR4-Wildtype (TR4(+/+)) littermates. Substantial increasing TR4(-/-) MEF apoptosis to UV-irradiation was correlated to the down-regulation of Bcl-2 RNA and protein expression and collaterally increased caspase-3 activity. Furthermore, this TR4-induced Bcl-2 gene expression can be suppressed by co-transfection with TR4 coregulators, such as androgen receptor (AR) and receptor-interacting protein 140 (RIP140) in a dose-dependent manner. Together, our results demonstrate that TR4 might function as an apoptosis modulator through induction of Bcl-2 gene expression.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Apoptosis* / radiation effects
  • COS Cells
  • Chlorocebus aethiops
  • Down-Regulation / genetics
  • Down-Regulation / radiation effects
  • Fibroblasts / metabolism
  • Fibroblasts / radiation effects
  • Gene Expression Regulation* / radiation effects
  • Humans
  • Mice
  • Nuclear Proteins / metabolism
  • Nuclear Receptor Interacting Protein 1
  • Promoter Regions, Genetic / genetics
  • Proto-Oncogene Proteins c-bcl-2 / genetics*
  • Receptors, Androgen / metabolism
  • Receptors, Steroid / genetics
  • Receptors, Steroid / metabolism*
  • Receptors, Thyroid Hormone / genetics
  • Receptors, Thyroid Hormone / metabolism*
  • Transcription, Genetic / radiation effects
  • Ultraviolet Rays

Substances

  • Adaptor Proteins, Signal Transducing
  • NRIP1 protein, human
  • Nr2c2 protein, mouse
  • Nuclear Proteins
  • Nuclear Receptor Interacting Protein 1
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, Androgen
  • Receptors, Steroid
  • Receptors, Thyroid Hormone