PPARγ expression is reduced in hypoxia. (A) Experimental design for (1B–1E). Block arrows indicate length of time in differentiation media. Different shades indicate various levels of oxygen tension. (B) PPARγ mRNA levels, measured by qPCR, in undifferentiated (stem) and differentiated (day 7) WT-TS cells under normoxia and hypoxia; * indicates statistically significant difference between levels in normoxia and hypoxia. (C) PPARγ protein levels assayed by western blot, in undifferentiated (stem) and differentiated (days 1, 4, and 7) WT-TS cells under normoxia and hypoxia. (D) PPARγ protein levels of WT-TS cells differentiated over a 4-day timecourse, in a range of oxygen tensions (20%, 8%, 5%, and 2%). (E) PPARγ protein levels in cells differentiated for 4 days in normoxia (20% oxygen), and then either switched to 2% oxygen, or maintained in normoxia, for the indicated number of hours. PPARγ, peroxisome proliferator-activated receptor-γ; TS, trophoblast stem; qPCR, quantitative polymerase chain reaction; WT, wild-type.