Vitamin D receptor interaction with specific DNA. Association as a 1,25-dihydroxyvitamin D3-modulated heterodimer.

摘要: The vitamin D receptor (VDR) is a member of the steroid gene family. In this report, we examine nature specific VDR DNA binding utilizing D-responsive element derived from human osteocalcin promoter. Association with 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) responsive (VDRE) in vitro was characterized on VDRE affinity columns by both weak and strong interactions. Weak interaction property itself, monomeric nature, determined exclusively VDR's DNA-binding domain. Strong interaction, contrast, dependent upon an intact molecule as well heterologous mammalian cell nuclear accessory factor (NAF). Heteromeric between NAF independent domain, suggesting presence functional dimerization domain separate that for binding. Direct association immobilized revealed does not require DNA. Most importantly, while occupancy 1,25(OH)2D3 required interactions either or NAF, hormone increased apparent relative approximately 10-fold. These studies suggest high requires additional structure located within steroid-binding region. This protein subdomain interacts regulated 1,25(OH)2D3.