Activation (nuclear translocation) of NFκB precludes RAR-DNA interactions while RAR reversibly interacts with NFκB-DNA complexes in a ligand dependent manner. (A) RAR and RXR gelshift oligonucleotides were employed to contrast RAR and RXR-DNA binding activity in WT and mIκB-Line 1 tumor cells under basal and PMA (NFκB) induced conditions. Under basal conditions, we observe increased RAR-DNA binding activity in mIκB cells contrasted to their WT counterparts (1, 3), and a decrease in RAR-DNA binding activity upon activation of NFκB with PMA in both cell types (2, 4). No appreciable differences in RXR-DNA binding activity were observed under all experimental conditions. (B) NFκB gelshift oligonucleotides conjugated to agarose beads were used to pull down NFκB and NFκB associated proteins, from the total protein lysate of cells exposed to at-RA +/- AGN193109 for 24-h. We consistently pulled down comparable amounts of RelA-NFκB and observed a dose dependent increase in the association of RAR with NFκB-DNA complexes with increasing concentrations of at-RA, and its reversal by increasing concentration of AGN193109.