Fig. 2.

Tead4^-/- embryos developed a blastocoel in the absence of Tead4^+/+ or Tead4^+/- embryos and could produce outgrowths. Two-cell embryos were isolated at E1.5 from Tead4^-/- matings. (A) The six Tead4^-/- embryos from a single litter were cultured for 4 days in KSOM and 5% O₂, as in Fig. 1A. All of them formed a blastocoel (BC). Trophectoderm (TE), inner cell mass (ICM) and zona pellucida (ZP) are indicated for four of the embryos (numbered 1-4). (B) Blastocysts 1 and 2 were transferred to gelatin-coated tissue culture plates and cultured in blastocyst outgrowth medium for 3 days. One blastocyst managed a partial outgrowth; one did not. Blastocysts 3 and 4 were treated with acidic Tyrode’s solution (+AT) to remove their ZP prior to transfer. Both embryos produced an outgrowth. Trophoblast giant cells (TGC) are indicated. (C) Genotypes of blastocysts or outgrowths confirmed they were Tead4^-/-. Tail samples from Tead4^lox/lox (L/L), Tead4^lox/- (L/-) and Tead4^+/- (+/-) were used as controls.