Figure 2.

ESCs with Defective BMP Signaling Are Eliminated by Apoptosis upon Exit of the Ground State of Pluripotency

(A) Growth rates (in cell doublings per day) of control and Bmpr1a^−/− ESCs between days 3 and 4 of culture indicate that, while Bmpr1a^−/− ESCs are eliminated, control cells undergo compensatory proliferation. Sep., separate culture; Co-Cul., coculture.

(B) Ratio obtained by flow cytometry and confocal images of Bmpr1a^−/− and control cells indicates that addition between days 2 and 4 of coculture of the pancaspase inhibitor ZVAD-FMK blocks the elimination of Bmpr1a^−/− ESCs. DMSO, dimethyl sulfoxide.

(C) Growth curves (left) and ratios (right) of control and Bmpr1a^−/− ESCs showing that the elimination of mutant cells occurs under EpiSC culture conditions.

(D) Ratio of control to Bmpr1a^−/− ESCs showing that the outcompetition of Bmpr1a^−/−-GFP ESCs is prevented by FCS + Lif, BMP4 + Lif, 2i, CHIR99021, or PD0325901. A minimum of three independent experiments were performed, and the average ± SEM was plotted. ^∗p < 0.05, and ^∗∗p < 0.01; a one-way analysis of variance (ANOVA) followed by Tukey’s test.

See also Figures S2 and S3 and Table S1.