Vitamin D-dependent recruitment of DNA-PK to the chromatinized negative vitamin D response element in the PTHrP gene is required for gene repression by vitamin D.
The mechanism of transcriptional repression by nuclear hormone receptors, especially in the presence of the ligands, is largely unknown. We previously reported that 1,25-dihydroxyvitamin D(3) (1,25 vitamin D3) inhibited expression of the parathyroid hormone-related polypeptide (PTHrP) gene through the interaction between the liganded monomeric vitamin D receptor (VDR) and the negative DNA element in the PTHrP gene (nVDRE(RP)). In this study, we employed chromatin immunoprecipitation (ChIP) assay and confirmed that 1,25 vitamin D3 recruited DNA-dependent protein kinase (DNA-PKcs) to the chromatinized nVDRE(RP). Conversely, the regulatory subunits of DNA-PK were associated with the nVDRE(RP) sequences only when 1,25 vitamin D3 was absent. VDR was constitutively associated with these chromatinized nVDRE(RP) sequences. Furthermore, DNA-PKcs could phosphorylate VDR in vitro. We raise a possibility that a conformational change of VDR through its phosphorylation mediated by DNA-PKcs underlies the mechanism of gene repression by 1,25 vitamin D3-bound VDR.
Endocrine Unit, Department of Endocrinology and Nephrology, University of Tokyo School of Medicine, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8655, Japan. okbgeni-tky@umin.ac.jp
Tomoki
T
Okazaki
Shigeki
S
Nishimori
Etsuro
E
Ogata
Toshiro
T
Fujita
D000730:Androstadienes / Q000378:metabolism; D000818:Animals; D002117:Calcitriol / Q000378:metabolism*; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism*; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors / Q000378:metabolism; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D009687:Nuclear Proteins; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones / Q000235:genetics*; D010766:Phosphorylation; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism; D030181:Vitamin D Response Element; D000077191:Wortmannin
D000730:Androstadienes; D002843:Chromatin; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones; D018167:Receptors, Calcitriol; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases; D002117:Calcitriol; D000077191:Wortmannin