Methods of generating a synthetic embryo

A method of generating a synthetic embryo, the method comprising:

• (a) inducing expression of an endogenous factor that induces differentiation to trophectoderm cells in a subpopulation of naïve pluripotent stem cells (PSCs) to obtain trophectoderm primed cells;
• (b) inducing expression of an endogenous factor that induces differentiation to extra embryonic primitive endodermal cells in a second subpopulation of naïve PSCs to obtain extra embryonic primitive endodermal primed cells;
• (c) mixing said trophectoderm primed cells and said extra embryonic primitive endodermal primed cells with naïve PSCs under conditions that allow formation of aggregated cells;
• and
• (d) ex-utero culturing said aggregated cells following said (c) in a static culture followed by a dynamic culture,
• wherein said (a) comprises culturing said subpopulation of naïve PSCs with a factor selected from the group consisting of a TGFR inhibitor, a FGFR inhibitor, a MEK/ERK inhibitor, a BMP4, a JAK inhibitor, a ROCK pathway inhibitor, FGF4, FGF2, heparin, a SUMOylation inhibitor, a Histone Deacetylase inhibitor, a HIPPO signaling pathway inhibitor, and a factor that induces YAP nuclear translocation, under conditions enabling expression of said endogenous factor, starting within 6 days—6 hours prior to said mixing,
• and wherein said (b) comprises culturing said second subpopulation of naïve PSCs with a factor selected from the group consisting of a GSK-3 inhibitor, WNT ligand, heparin, FGF2, FGF4, PDGF, leukemia inhibitory factor (LIF), and insulin, under conditions enabling expression of said endogenous factor, starting within 6-6 hours prior to said mixing,
• thereby generating the synthetic embryo.