Abstract
Vitamin D signaling is believed to be transduced by a heterodimeric receptor complex that binds to specific sequences of DNA termed vitamin D response elements (VDREs) in the promoter regions of target genes. However, recent studies have suggested that considerable flexibility exists in the types of binding sites the vitamin D receptor (VDR) is capable of recognizing, including some that bind VDR homodimers. In this report, a screening method involving immuno-selection and PCR amplification was utilized to examine genomic binding sites for the receptor. Four individual fragments ranging in size from ca. 250-320 bp were nominally isolated from the amplified pool of captured fragments for further analysis. Each of the four sequences was capable of forming specific, unique VDR complexes using recombinant human VDR (rhVDR) alone or rhVDR heteromers formed in conjunction with the addition of recombinant human retinoid X receptor α (rhRXRα). Two of these fragments exhibited significant hormone-dependent repression of luciferase activity when linked to a thymidine kinase driven reporter vector. DNaseI foot-printing revealed specific binding over DR+3 or related half-site sequences found within both of these DNA fragments. The results from this study demonstrate that specific, functional binding sites for the VDR can be successfully isolated from genomic DNA and should aid in the discovery of genes regulated by the steroid hormone.
Original language | English |
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Pages (from-to) | 188-194 |
Number of pages | 7 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 283 |
Issue number | 1 |
DOIs | |
State | Published - 2001 |
Bibliographical note
Funding Information:The authors thank Ms. Holli Gravatte and Ms. Anne Rowan for their excellent technical assistance. This work was supported by NIH Grants DK-47883 and DK-54276 (N.J.K.) and Dialysis Clinic Incorporated (N.J.K., S.K.).
Keywords
- Gene regulation
- Genome
- Hormone response element
- Vitamin D
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology