A central dinucleotide within vitamin D response elements modulates DNA binding and transactivation by the vitamin D receptor in cellular response to natural and synthetic ligands

Gert Jan C.M. Van Den Bemd, Mila Jhamai, Ada Staal, André J. Van Wijnen, Jane B. Lian, Gary S. Stein, Huibert A.P. Pols, Johannes P.T.M. Van Leeuwen

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Abstract

There is considerable divergence in the sequences of steroid receptor response elements, including the vitamin D response elements (VDREs). Two major VDREcontaining and thus 1,25-dihydroxyvitamin D3 (1,25- (OH)2D3)-regulated genes are the two non-collagenous, osteoblast-derived bone matrix proteins osteocalcin and osteopontin. We observed a stronger induction of osteopontin than osteocalcin mRNA expression by 1,25- (OH)2D3. Subsequently, we have shown that vitamin D receptor/retinoid X receptor α (VDR/RXCRα) heterodimers bind more tightly to the osteopontin VDRE than to the osteocalcin VDRE. Studies using point mutants revealed that the internal dinucleotide at positions 3 and 4 of the proximal steroid half-element are most important for modulating the strength of receptor binding. In addition, studies with VDRE-driven luciferase reporter gene constructs revealed that the central dinucleotide influences the transactivation potential of VDR/ RXRα with the same order of magnitude as that observed in the DNA binding studies. The synthetic vitamin D analog KH1060 is a more potent stimulator of transcription and inducer of VDRE binding of VDR/RXR in the presence of nuclear factors isolated from ROS 17/2.8 osteoblast-like cells than the natural ligand 1,25- (OH)2D3. Interestingly, however, KH1060 is comparable or even less potent than 1,25-(OH)2D3 in stimulating VDRE binding of in vitro synthesized VDR/RXRα. Thus, the extent of 1,25-(OH)2D3- and KH1060-dependent binding of VDR/RXRα is specified by a central dinucleotide in the VDRE, and the ligand-induced effects on DNA binding are in part controlled by the cellular context of nuclear proteins.

Original languageEnglish (US)
Pages (from-to)14539-14546
Number of pages8
JournalJournal of Biological Chemistry
Volume277
Issue number17
DOIs
StatePublished - Apr 26 2002

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Van Den Bemd, G. J. C. M., Jhamai, M., Staal, A., Van Wijnen, A. J., Lian, J. B., Stein, G. S., Pols, H. A. P., & Van Leeuwen, J. P. T. M. (2002). A central dinucleotide within vitamin D response elements modulates DNA binding and transactivation by the vitamin D receptor in cellular response to natural and synthetic ligands. Journal of Biological Chemistry, 277(17), 14539-14546. https://doi.org/10.1074/jbc.M111224200