Fig. 3

AscPNa impaired the degradation of RA. a-b Different concentrations of RA were used during reprogramming of MEFs with N2B27 medium in the presence or absence of 0.16 mM AscPNa. The expression of Cyp26a1 (a) and Cyp26b1 (b) was determined by qPCR. c-f EGFP reporter genes driven by different promoters were delivered to MEFs via lentivirus system (c). N2B27 medium was used 24 h after the delivery. 10 nM RA was included in the medium for the next three days. After the removal of RA, 0.16 mM AscPNa and PBS were used in two different groups. EGFP fluorescence was determined at indicated time points. RARE-containing mini promoter was used to indicate RA concentration in (d). Promoters of Cyp26a1 (e) and Cyp26b1 (f) were also used. g-h MEFs were cultured in N2B27 medium. Different concentrations of RA were used for three days. The activities of the promoters of Cyp26a1 and Cyp26b1 (g) and the expression of Cyp26a1 and Cyp26b1 (h) were determined by FACS and qPCR, respectively. i-k The bind sites of ZEB1 and TWIST1 were identified on the promoters of Cyp26a1 and Cyp26b1 by Pscan software, respectively. Promoter assay confirmed the abilities of ZEB1 and TWIST1 to affect the functions of the promoters of Cyp26a1 and Cyp26b1. The comparisons were preformed between RA-treated groups and corresponding control (DMSO) groups or between indicated groups with one-way ANOVA except in (d-f). The comparisons in (d-f, j-k) were preformed between AscPNa⁺ and AscPNa⁻ groups or between pro or promu with two-way ANOVA. Experiments were repeated for at least five times (n ≥ 5). Standard deviations were provided