体外培养的干细胞具有不同的发育能力，在微注射到植入前的哺乳动物胚胎中后，可以为胚胎或胚胎外组织作出贡献。然而，培养的干细胞是否能独立地产生具有胚胎和胚胎外区的整个原肠胚样结构，仍是未知数。在这里，以色列科学家最近建立的一个体外延长自然胚胎宫外生长的平台，以生成小鼠胃化后的合成全胚胎模型（sEmbryos），同时具有胚胎和胚胎外的部分，仅从幼稚的ESCs开始。sEmbryos能充分完成胃肠发育，通过关键的发育里程碑前进，并在复杂的胚外区间发展器官祖先，类似于E8.5期小鼠胚胎。我们的研究结果突出了幼稚多能细胞的可塑性，它们可以自我组织，并在功能上重建和模拟整个哺乳动物胚胎，超过原肠胚层。

In vitro cultured stem cells with distinct developmental capacities can contribute to embryonic or extra-embryonic tissues after microinjection into pre-implantation mammalian embryos. However, whether cultured stem cells can independently give rise to entire gastrulating embryo-like structures with embryonic and extra-embryonic compartments, remains unknown. Here we adapt a recently established platform for prolonged ex utero growth of natural embryos, to generate mouse post-gastrulation synthetic whole embryo models (sEmbryos), with both embryonic and extra-embryonic compartments, starting solely from naïve ESCs. This was achieved by co-aggregating non-transduced ESCs, with naïve ESCs transiently expressing Cdx2- and Gata4- to promote their priming towards trophectoderm and primitive endoderm lineages, respectively. sEmbryos adequately accomplish gastrulation, advance through key developmental milestones, and develop organ progenitors within complex extra-embryonic compartments similar to E8.5 stage mouse embryos. Our findings highlight the plastic potential of naïve pluripotent cells to self-organize and functionally reconstitute and model the entire mammalian embryo beyond gastrulation.