The third and fourth weeks of gestation in primates are marked by several developmental milestones, including gastrulation and the formation of organ primordia. However, our understanding of this period is limited due to restricted access to in vivo embryos. To address this gap, we developed an embedded 3D culture system that allows for the extended ex utero culture of cynomolgus monkey embryos for up to 25 days post-fertilization. Morphological, histological, and single-cell RNA-sequencing analyses demonstrate that ex utero cultured monkey embryos largely recapitulated key events of in vivo development. With this platform, we were able to delineate lineage trajectories and genetic programs involved in neural induction, lateral plate mesoderm differentiation, yolk sac hematopoiesis, primitive gut, and primordial germ-cell-like cell development in monkeys. Our embedded 3D culture system provides a robust and reproducible platform for growing monkey embryos from blastocysts to early organogenesis and studying primate embryogenesis ex utero.

灵长类动物妊娠的第三周和第四周以几个发育里程碑为标志，包括原肠胚形成和器官原基的形成。然而，由于体内胚胎的获取受限，我们对这一时期的了解有限。为了解决这一差距，我们开发了一个嵌入式 3D 培养系统，允许在受精后长达 25 天的食蟹猴胚胎延长子宫外培养。形态学、组织学和单细胞 RNA 测序分析表明，子宫外培养的猴子胚胎在很大程度上概括了体内关键事件发展。有了这个平台，我们能够描绘涉及猴子神经诱导、侧板中胚层分化、卵黄囊造血、原始肠道和原始生殖细胞样细胞发育的谱系轨迹和遗传程序。我们的嵌入式 3D 培养系统提供了一个强大且可重复的平台，用于将猴子胚胎从囊胚培养到早期器官发生，以及研究灵长类动物的子宫外胚胎发生。