Figure 5.

Genomic response elements. Nuclear receptors bind to genomic response elements (RE) that come in a variety of forms. (A) Members of the SR subfamily bind to palindromic repeats (shown as red DNA cartoon). These repeats are separated by different spacer lengths (shown as yellow DNA cartoon). As examples, the ER DBD – estrogen response elements (ERE) and GR DBD – glucocorticoid response element (GRE) crystal structures are shown. (B) Most other NRs bind to direct repeats, which can also be separated by spacers from 0 to 5 bp. The structures of the RXR‐RAR DBD heterodimer is shown in complex with a DR with 1 bp spacer (DR1) and the VDR homodimer DBD is shown in complex with a DR with 3 bp spacer (DR3). (C) Although rare, some NRs bind to DNA as a monomer to extended half site sequences. Examples include LRH‐1 DBD and SF‐1 DBD (PDBs, from left to right: top row – http://firstglance.jmol.org/fg.htm?mol=4AA6, http://firstglance.jmol.org/fg.htm?mol=1DSZ, and http://firstglance.jmol.org/fg.htm?mol=5L0M; bottom row – http://firstglance.jmol.org/fg.htm?mol=3FYL, http://firstglance.jmol.org/fg.htm?mol=1KB4, and http://firstglance.jmol.org/fg.htm?mol=2FF0).