Single-cell RNA-sequencing of mouse embryoids at Day 8

Generating properly organized and differentiated embryonic structures in vitro from aggregates of pluripotent cells remains a major challenge to overcome. In the living embryo, the interplay between morphogens and their antagonists set up gradients of activity that instruct cells about their fate, leading to patterning and morphogenesis. Here we show that experimentally engineering a morphogen signaling center within an aggregate of mouse pluripotent stem cells is sufficient to mimic in vitro the function of an embryo organizer and to trigger embryonic development. The resulting embryoids are extensively patterned along their anterior-posterior and dorsal-ventral axes, with formation of three germ layers through a process of gastrulation and differentiation of germ layer derivatives similar to those of a neurula-stage mouse embryo. Overall design: Dissociated cells from a pool of 90 embryoids at Day 8 of development fixed in methanol.