Lawson K A, Meneses J J, Pedersen R A
Dev Biol. 1986 Jun;115(2):325-39. doi: 10.1016/0012-1606(86)90253-8.
The fate of the embryonic endoderm (generally called visceral embryonic endoderm) of midstreak to neural plate stages of the mouse embryo was studied by microinjecting horseradish peroxidase (HRP) into single axial endoderm cells in situ, and tracing the labeled descendants to early somite stages in vitro. Axial endoderm cells along the anterior fifth of the late streak/neural plate stage embryo contributed descendants either to the yolk sac endoderm or to the anterior intestinal portal. Cells of the exposed head process contributed to the trunk endoderm and notochord; neighboring endoderm cells contributed to the dorsal foregut. Contributions to the ventral foregut came from endoderm at, and anterior to, the distal tip of the younger, midstreak embryo (in which the head process was not yet exposed). Endoderm over the primitive streak contributed to the postsomite endoderm. We argue from these results and those in the literature that during gastrulation the axial embryonic endoderm is of mixed lineage: (1) an anterior population of cells is derived from primitive endoderm and contributes to the yolk sac endoderm; (2) a population at, and anterior to, the distal tip of the midstreak embryo, extending more anteriorly at late streak/neural plate stages, is presumed to emerge from primitive ectoderm at the beginning of gastrulation and contributes to the foregut and anterior intestinal portal; (3) the axial portion of the head process that begins to incorporate into the ventral surface at the late streak stage contributes to notochord and trunk endoderm. Cells or their descendants that were destined to die within 24 hr were evident at the midstreak stage. There was a linear trend in the incidence of cell death among labeled cells at the late streak/neural plate stages, ranging from 27% caudal to the node to 57% in the anterior fifth of the embryo. The surviving axial endoderm cells divided sufficiently fast to double the population in 24 hr.
通过将辣根过氧化物酶（HRP）原位显微注射到小鼠胚胎中轴内胚层的单个细胞中，并在体外追踪标记的后代至早期体节阶段，研究了小鼠胚胎从中条期到神经板期的胚胎内胚层（通常称为内脏胚胎内胚层）的命运。沿着晚期条带/神经板期胚胎前1/5的中轴内胚层细胞的后代，要么进入卵黄囊内胚层，要么进入前肠门。暴露的头突细胞形成躯干内胚层和脊索；相邻的内胚层细胞形成背侧前肠。对腹侧前肠的贡献来自较年轻的中条期胚胎（头突尚未暴露）远端尖端及其前方的内胚层。原条上方的内胚层形成体节后内胚层。我们从这些结果以及文献中的结果推断，在原肠胚形成过程中，中轴胚胎内胚层是混合谱系的：（1）前部细胞群源自原始内胚层，形成卵黄囊内胚层；（2）中条期胚胎远端尖端及其前方的细胞群，在晚期条带/神经板期更向前延伸，推测在原肠胚形成开始时从原始外胚层产生，形成前肠和前肠门；（3）在晚期条带期开始并入腹侧表面的头突的中轴部分，形成脊索和躯干内胚层。在中条期就明显可见注定在24小时内死亡的细胞或其后代。在晚期条带/神经板期，标记细胞中的细胞死亡率呈线性趋势，从节点后方的27%到胚胎前1/5的57%不等。存活的中轴内胚层细胞分裂速度足够快，能在24小时内使细胞数量翻倍。
