Figure 1. expression of primitive endoderm cell fate markers gradually increased and nanog decreased in developing embryoid bodies.

Embryoid bodies were produced from R63 mES cells using the hanging drop method. Development of the embryoid body was monitored over ten days. (A) Light microscopy images show the gradual increase in size of the embryoid bodies as well as increased heterogeneity, loss of circularity and formation of cystic cavities at later timepoints. Scale bars 200 µm. (B) Whole-mount immunostaining showing nuclear localisation of Gata6, Gata4, and Hnf4α on days 3, 5, 7, and 10 of embryoid body development. The percentage of positive nuclei for each protein is shown graphically. The number of positive nuclei increased, reaching a maximum on day 7. (C) Whole-mount immunostaining showing nuclear localisation of Nanog. The number of positive nuclei rapidly decreased, with no positive cells seen on days 7 or 10. The percentage of positive nuclei for each protein is shown graphically. Data is from at least 3 independent experiments, error bars are standard error of the mean (SEM). Statistical analysis is a one-way Anova with a Tukey’s post-hoc test, (*P = 0.1–0.5, **p = 0.001–0.01, ***p<0.001). Dotted lines represent position that the relevant orthogonal or aerial images were taken. Scale bars 10 µm.