FIGURE 4.
β-Apocarotenoids antagonize ATRA-induced transactivation of retinoic acid receptors. Histograms of activation of RARE reporter genes in cells transfected with retinoic acid receptors α (left), β (middle), and γ (right). Percent of maximal activation of cells treated with 10−5 m ATRA alone (left most bar in each histogram) or co-treated with 10−5 m ATRA and 10−5 m of the β-apocarotenoids resulting from cleavage at the a, b, c, or d sites are shown in a, b, c, and d, respectively (n = 3 to 6); mean ± S.D. Compound abbreviations are given on Fig. 1.