Arrangement of the chromosomal gene and domains of the VDR. The exons encoding the various domains and structural motifs in the
VDR protein are shown. The two zinc finger modules shown on the left side of the figure are encoded by exons 2 and 3. The position of thea-helices
(H1-H12) and b-turn (S1) are shown as shaded and open boxes, respectively, and the exons from which they are derived are illustrated. The
E1 and AF-2 regions are shown above the a-helices.