Figure 5.

Regulation of hAP expression by 4′OHT in primary embryonic fibroblasts isolated from 15-day-old chimeric embryos generated from GTEV49-IGTE110 ES cells. (A and B) Histochemical analysis of hAP activity in fibroblasts cultured with 4′OHT (1 μM, 48 h) (B) or with vehicle alone (A). (C) Quantification of hAP activity in protein lysates prepared from embryonic fibroblasts treated with 4′OHT for 24, 48, and 72 h with 1 μM 4′OHT (+OHT) or for 96 h with vehicle alone (−OHT). OD, optic density at 420 nm. (Scale bars = 100 μM.)