Cell-type-specific regulation of the retinoic acid receptor mediated by the orphan nuclear receptor TLX

Mol Cell Biol. 2000 Dec;20(23):8731-9. doi: 10.1128/MCB.20.23.8731-8739.2000.

Abstract

Malformations in the eye can be caused by either an excess or deficiency of retinoids. An early target gene of the retinoid metabolite, retinoic acid (RA), is that encoding one of its own receptors, the retinoic acid receptor beta (RARbeta). To better understand the mechanisms underlying this autologous regulation, we characterized the chick RARbeta2 promoter. The region surrounding the transcription start site of the avian RARbeta2 promoter is over 90% conserved with the corresponding region in mammals and confers strong RA-dependent transactivation in primary cultured embryonic retina cells. This response is selective for RAR but not retinoid X receptor-specific agonists, demonstrating a principal role for RAR(s) in retina cells. Retina cells exhibit a far higher sensitivity to RA than do fibroblasts or osteoblasts, a property we found likely due to expression of the orphan nuclear receptor TLX. Ectopic expression of TLX in fibroblasts resulted in increased sensitivity to RA induction, an effect that is conserved between chick and mammals. We have identified a cis element, the silencing element relieved by TLX (SET), within the RARbeta2 promoter region which confers TLX- and RA-dependent transactivation. These results indicate an important role for TLX in autologous regulation of the RARbeta gene in the eye.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Chickens
  • Conserved Sequence
  • Evolution, Molecular
  • Gene Silencing*
  • Humans
  • Molecular Sequence Data
  • Orphan Nuclear Receptors
  • Promoter Regions, Genetic
  • Receptors, Cytoplasmic and Nuclear / genetics*
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Receptors, Retinoic Acid / genetics*
  • Response Elements*
  • Species Specificity
  • Tretinoin / pharmacology

Substances

  • NR2E1 protein, human
  • Orphan Nuclear Receptors
  • Receptors, Cytoplasmic and Nuclear
  • Receptors, Retinoic Acid
  • retinoic acid receptor beta
  • Tretinoin

Associated data

  • GENBANK/AF220160
  • GENBANK/AF220161
  • GENBANK/AF220162
  • GENBANK/AF220163
  • GENBANK/AF220532