Fig. 1: Differential cell movements between epiblast and primitive endoderm contribute to fate segregation in the ICM.
From: Coupling of cell shape, matrix and tissue dynamics ensures embryonic patterning robustness
a, Schematic and immunostaining images of blastocysts and ICMs at E3.5 and E4.5 stages. b, Quantification of total cell number in the ICM from blastocysts and isolated ICMs at stage E3.5, blastocysts and isolated ICMs at stage E4.5 and isolated ICMs cultured in vitro for 24 h from stage E3.5 to E4.5. n = 33, 30, 40, 21 and 31 embryos for the different groups, respectively. Independent-samples t-test between E3.5 blastocysts and E3.5 ICMs; P = 0.106. One-way analysis of variance (ANOVA) between E4.5 blastocysts, E4.5 ICMs, and E3.5 ICMs + 24 h; P = 0.145. c, Time-lapse imaging of a representative ICM isolated from an E3.5 blastocyst expressing PrE-specific H2B-GFP (PdgfraH2B-GFP) and ubiquitous H2B-mCherry (R26-H2B-mCherry). n = 8 datasets from three independent experiments. Time is indicated in h:min. t = 00:00, stage E3.5 + 3 h, following completion of immunosurgery. d, Schematic representation of single-cell tracking of EPI and PrE cells from isolated ICMs from c. Line plots indicating radial distances of all cells from one representative ICM until the E4.0 stage. The colour of the line indicates cell fate: PrE, green; EPI, magenta. Shaded regions show spatial dispersion as mean ± s.d. of cell position along ICM radial axis. The geometric centroid of the ICM is considered as d = 0.0 and ICM outer surface is considered as d = 1.0 to normalize the cell position across samples. Time-series curves for individual cell positions were smoothed using a rolling average. e, Quantification of sorting score for isolated ICMs between stage E3.5 and E4.0. Data from n = 8 ICMs. For estimation of sorting score, see Methods. f, Plots for radial cell position from tracking of PrE (top) and EPI (bottom) cell movements in isolated ICMs. Time-series curves for individual cell positions were smoothed using a rolling average. Cell-tracking data from n = 158 PrE cells and n = 131 EPI cells from 8 ICMs. g, Schematic for analysis of PrE (top) and EPI (bottom) cell movements. Cell displacement along the radial axis is classified as inward or outward movement. h, Polar plots indicating preferential direction of cell movements among PrE and EPI. Measurements are binned according to radial cell position and time. The mean displacement of each interval is plotted, colour indicates magnitude and direction of movement. Scale bars, 20 μm. NS, not significant.
