FIG. 4.

Point mutations of the NR boxes inhibit TIF2 binding to TR-RXR heterodimers differently. Electrophoretic mobility shift assays were performed with in vitro-translated TRβ and RXRβ and bacterially expressed GST-tagged TIF2 IAD variants. The interactions of GST (lanes 1 and 2) and GST-IAD wt (lanes 3 and 4) with the heterodimer were analyzed in the absence or presence of both T3 (100 μM) and 9-cis-retinoic acid (9-cis RA) (100 μM), as indicated. The interactions with the mutated variants were analyzed in the presence of both hormones.