The Vitamin D Receptor--Structure and Transcriptional Activation

Although recent work has provided a clearer picture of the binding of 1,25-(OH)2D3 to VDR and the binding of VDR to the vitamin D response element resulting in altered transcriptional activity, much remains unknown. Certainly RXR is a required participant in all known transcriptional activation initiated by VDR. However, the participation of other transcription factors such as TFIIB and TFIID, and of co-activators or co-repressors remains to be established. Elucidation of the 3-dimensional structure of the VDR, the changes that occur following ligand binding, and its interaction with transcriptional machinery is required to achieve an understanding of the molecular events in transcriptional regulation of target genes by 1,25-(OH)2D3.