Figure 5. Hyper-isomerase activity and faster regeneration of 11cRAL in Fatp4−/− mice.
(A) Retinoid isomerase (RI) activities in WT and Fatp4−/− RPE cells. Synthesis of 11cROL by WT and Fatp4−/− RPE homogenates during the indicated incubation times was measured by HPLC. Asterisks indicate statistically significant differences (P < 0.05). Error bars show SD (n = 4). (B) Representative HPLC chromatograms of retinoids from WT and Fatp4−/− RPE homogenates assayed for 90 minutes in (A). The peaks corresponding to 11cROL are marked (arrow). (C) Immunoblot analysis showing similar expression levels of RPE65 in WT and Fatp4−/− RPE cells. RPE cells from RPE65-deficient rd12 mice were used as a negative control. (D) Relative contents of 11cRAL in the retinas from mice immediately after photo-bleaching (PB) of the visual pigment, or from mice kept in darkness for the indicated times after PB.