Retinoid X receptor and its partners in the nuclear receptor family

Retinoid X receptor (RXR) and its dimerization partners in the nuclear receptor family recognize DNA response elements in which two AGGTCA binding sites are arranged in tandem. Target site selection by these complexes requires the spacing between the binding sites to act as the identity element. With the recent determination of three-dimensional structures of several different DNA-binding complexes of RXR, together with studies of protein conformational changes, it is clear how the interactions of RXR with its partners are precisely tuned to match the spacing between their DNA binding sites.