Single cell RNA seq of mouse embryos from E7.0, E7.25 and E7.5

During mouse gastrulation, the formation of germ layers proceeds concurrently with the transition pluripotency state and the allocation of the multipotent epiblast cells to the germ layer derivatives. Lineage analysis and fate-mapping studies have revealed that groups of cells in different regions of the epiblast and the primitive streak of the gastrulating embryo are allocated to separate progenitors of the ectoderm, mesoderm and endoderm lineages three germ layers with descendants of each progenitor contributing to specific types of germ layer derivatives. Spatiotemporal transcriptomic analysis of the epiblast cell population has inferred that besides the allocation of the epiblast cells to progenitors of germ layers, a population of putative mesendoderm progenitors may be present in the gastrulating embryos. Single cells were isolated from mouse embryos at the gastrulation stages of E7.0, E7.25 and posterior region of E7.5 mouse embryo在小鼠原肠胚形成（gastrulation）过程中，胚层形成与多能性状态转变同步推进，多能上胚层（epiblast）细胞同时被分配至各胚层衍生物的前体群体。通过谱系分析与命运图谱研究可知，原肠胚的上胚层及原条（primitive streak）不同区域的细胞群，会被定向分配至外胚层（ectoderm）、中胚层（mesoderm）与内胚层（endoderm）这三个胚层的独立祖细胞；每类祖细胞的子代细胞均可分化为特定类型的胚层衍生物。针对上胚层细胞群的时空转录组学（spatiotemporal transcriptomic）分析显示，除上胚层细胞向胚层祖细胞分化外，原肠胚中还可能存在一类潜在的中内胚层祖细胞（mesendoderm progenitors）群体。本研究从处于原肠胚形成阶段的E7.0、E7.25小鼠胚胎，以及E7.5小鼠胚胎的后部区域中分离得到了单个细胞。