Extended Data Fig. 4: Leakage of blastocoel fluid during trophectoderm cell division leads to the collapse of blastocysts at mature stage.
From: Hydraulic control of mammalian embryo size and cell fate
a, Images of a blastocyst (at E4.25) showing blastocoel loaded with 4-kDa FITC–dextran dye, before (top) and after (bottom) collapse. Dye leakage following blastocyst collapse occurs preferentially at cell–cell junctions between mitotic trophectoderm cells (white arrows). Scale bar, 20 μm. b–d, Cavity diameter as a function of time (after E3.5) for 1/2 embryos treated with 2 μg ml−1 of aphidicolin (n = 11 embryos) (c) and 50 nM of nocodazole (n = 17 embryos) (d) compared to control 1/2 embryos (n = 17 embryos) (b). e, Images showing that nocodazole-treated 1/2 blastocysts that failed to expand upon initial collapse can re-cavitate upon washout. Scale bar, 30 μm. f, Cortical tension of mural trophectoderm cells measured during interphase (black) and metaphase (red) at mid- (E4.0) and late (E4.5) blastocyst stages. Different symbols correspond to the different cells being measured. Inset, image showing tension measurement for a trophectoderm cell undergoing mitosis at E4.5 (green indicates nucleus at M-phase). In a, e, f, representative examples from three independent experiments are shown.
