FIGURE 3.
β-Apocarotenoids do not transactivate retinoic acid receptors. Histograms of activation of RARE reporter genes in cells transfected with retinoic acid receptors α (left), β (middle), and γ (right). Normalized fold activation relative to vehicle-treated cells is shown for all-trans-retinoic acid (far left bar in each histogram) or the β-apocarotenoids resulting from cleavage at the “a”, “b”, “c”, or “d” sites from top to bottom, respectively. Compounds were tested individually at 10−5 m (n = 3–6); mean ± S.D. Compound definitions are given on Fig. 1.