Figure 2.

Eed and Ring1B are redundantly required for differentiation. (A) Teratomas formed by wild-type (wt), Eed^−/−, and Ring1B^−/− ES cells 3 wk after injection. dKO ES cells did not give rise to teratomas. (B) Immunohistochemical analysis of wild-type, Ring1B^−/−, and Eed^−/− teratomas using markers for endoderm (Troma1), mesoderm (smooth muscle actin [SMA]), and ectoderm (GFAP). (C) Double deficiency for PRC1 and PRC2 is not compatible with NS cell viability. Deletion of Ring1B in Eed-deficient NS cells by induction of CreERT2 with 4OHT caused cell death, whereas 4OHT had no effect on control Eed-deficient NS cells. (D) PCR analysis showing that induction of CreERT2 results in deletion of the conditional Ring1B^fl allele in Eed^−/− Ring1B^-/fl NS cells.