Ligand-triggered stabilization of vitamin D receptor/retinoid X receptor heterodimer conformations on DR4-type response elements

J Mol Biol. 2000 Feb 25;296(3):743-56. doi: 10.1006/jmbi.2000.3499.


Nuclear receptors integrate an incoming signal in the form of a nuclear hormone by undergoing a conformational change that results via co-activator proteins in an activation of the basal transcriptional machinery. The vitamin D(3) receptor is the nuclear receptor for 1alpha,25-dihydroxyvitamin D(3 )(1alpha,25(OH)(2)D(3)) and is known to function as a heterodimer with the retinoid X receptor on DR3-type 1alpha,25(OH)(2)D(3) response elements. Here, it could be demonstrated that DR4-type response elements are at least as effective as DR3-type 1alpha,25(OH)(2)D(3) response elements. Gel shift clipping analysis showed that vitamin D(3) receptor-retinoid X receptor heterodimers form in response to 1alpha, 25(OH)(2)D(3) and retinoid X receptor ligands, the pan-agonist 9-cis retinoic acid (9cRA) and the retinoid X receptor-selective retinoid CD2425, different conformations on the DR4-type element of the rat Pit-1 gene. Interestingly, on this response element the heterodimeric complexes of retinoid X receptor with the thyroid hormone receptor, the retinoic acid receptor and the benzoate ester receptor also displayed characteristic individual ligand-dependent complex formation. On the level of complex formation, utilizing DNA affinity and functional assays, only vitamin D(3) receptor-retinoid X receptor heterodimers showed a synergistic interaction of both ligands. However, the sensitivity of vitamin D(3) receptor-retinoid X receptor heterodimers to 1alpha,25(OH)(2)D(3) was found to be much higher than to retinoid X receptor ligands. Taken together, this study demonstrates a unique interaction potential of vitamin D(3) receptor and retinoid X receptor but also establishes DR4-type response elements as multi-functional DNA binding sites with a potential to integrate various hormone signalling pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • DNA / genetics
  • DNA / metabolism*
  • DNA-Binding Proteins / agonists
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Dimerization
  • Drug Synergism
  • Humans
  • Ligands
  • Protein Conformation
  • Rats
  • Receptors, Calcitriol / agonists
  • Receptors, Calcitriol / chemistry*
  • Receptors, Calcitriol / metabolism*
  • Receptors, Retinoic Acid / agonists
  • Receptors, Retinoic Acid / chemistry*
  • Receptors, Retinoic Acid / metabolism*
  • Receptors, Thyroid Hormone / agonists
  • Receptors, Thyroid Hormone / chemistry
  • Receptors, Thyroid Hormone / metabolism
  • Response Elements / genetics*
  • Retinoid X Receptors
  • Sequence Deletion / genetics
  • Substrate Specificity
  • Thermodynamics
  • Transcription Factor Pit-1
  • Transcription Factors / agonists
  • Transcription Factors / chemistry*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • DNA-Binding Proteins
  • Ligands
  • POU1F1 protein, human
  • Pou1f1 protein, rat
  • Receptors, Calcitriol
  • Receptors, Retinoic Acid
  • Receptors, Thyroid Hormone
  • Retinoid X Receptors
  • Transcription Factor Pit-1
  • Transcription Factors
  • DNA