FIGURE 6.

Differences in the ability of agonist to release different corepressor variants from RARα and PML-RARα. A, ATRA-mediated release of corepressor: calculated IC₅₀ values. The EMSA supershifts in Fig. 4A were repeated using SMRTϵ or NCoRω (Fig. 1D) and increasing concentrations of the retinoid agonists ATRA, AM-50, or 9-cis-retinoic acid (9-cis RA). The agonist concentration required to release 50% of each corepressor (IC₅₀) from the receptor-DNA complex was calculated; the means and S.E. are presented. B, ATRA-mediated release of corepressor: plotted results. The data that generated the IC₅₀ values in A are plotted as the percentage of receptor/corepressor complex remaining at each ATRA concentration (corepressor complex formed minus agonist is defined as 100%); the means and S.E. are presented (n = 7 for PML-RARα and RARα; n = 3 for PLZF-RARα). The values slightly below 0% reflect minor changes in receptor-DNA affinity caused by binding of agonist.