Zwaka Thomas P, Thomson James A
University of Wisconsin--Medical School and The National Primate Research Center, University of Wisconsin, Madison, WI 53715, USA.
Development. 2005 Jan;132(2):227-33. doi: 10.1242/dev.01586.
Because embryonic stem (ES) cells are generally derived by the culture of inner cell mass (ICM) cells, they are often assumed to be the equivalent of ICM cells. However, various evidence indicates that ICM cells transition to a different cell type during ES-cell derivation. Historically, ES cells have been believed to most closely resemble pluripotent primitive ectoderm cells derived directly from the ICM. However, differences between ES cells and primitive ectoderm cells have caused developmental biologists to question whether ES cells really have an in vivo equivalent, or whether their properties merely reflect their tissue culture environment. Here, we review recent evidence that the closest in vivo equivalent of an ES cell is an early germ cell.
由于胚胎干细胞（ES细胞）通常是通过培养内细胞团（ICM）细胞获得的，所以它们常常被认为等同于ICM细胞。然而，各种证据表明，ICM细胞在ES细胞衍生过程中会转变为另一种细胞类型。从历史上看，人们一直认为ES细胞与直接从ICM衍生而来的多能原始外胚层细胞最为相似。然而，ES细胞与原始外胚层细胞之间的差异使得发育生物学家质疑ES细胞在体内是否真的有等效物，或者它们的特性是否仅仅反映了其组织培养环境。在这里，我们回顾了最近的证据，即ES细胞在体内最接近的等效物是早期生殖细胞。
