Department of Biology, Clarkson University, Potsdam, New York.
Dev Dyn. 2020 Jan;249(1):76-87. doi: 10.1002/dvdy.16. Epub 2019 Feb 18.
Development of the vertebrate intestinal epithelial stem cell niche begins during embryogenesis but maturation occurs postembryonic. The intestinal mammalian crypt contains stem cells interspersed by secretory cells that play a role in regulation of proliferation. Epithelial cells are specified as either secretory or enterocytes as they migrate up the villi in mammals or fold in zebrafish. Zebrafish forms a functional intestine by the end of embryogenesis but takes another 4 weeks to develop the adult proliferation pattern.
We characterize development of the intestinal epithelial stem cell niche during the postembryonic period. During the first 2-weeks postembryogenesis, different groups of epithelial cells sequentially proceed through one or two cell cycles, appear to become quiescent, and remain at the interfold base. The third week begins asymmetric divisions with proliferative progeny moving up the folds. Apoptotic cells are not observed at the fold tip until the end of the fourth week. Secretory cells intersperse among interfold base proliferative cells, increasing in number during the third and fourth weeks with a coincident change in proliferation pattern.
Zebrafish postembryonic intestinal epithelial development consists of 2 weeks of slow proliferation followed by 2 weeks of metamorphosis to the adult structure. Developmental Dynamics 2019. © 2019 Wiley Periodicals, Inc.
脊椎动物肠上皮干细胞龛的发育始于胚胎发生期，但成熟发生在胚胎后。哺乳动物隐窝包含散布在其中的干细胞，这些细胞在增殖调控中发挥作用。上皮细胞在迁移到哺乳动物的绒毛或折叠在斑马鱼中时被指定为分泌细胞或肠细胞。斑马鱼在胚胎发生期末形成功能性肠道，但还需要另外 4 周才能发展出成年增殖模式。
我们描述了胚胎后时期肠上皮干细胞龛的发育情况。在胚胎发生后两周内，不同的上皮细胞群依次经历一个或两个细胞周期，似乎进入静止状态，并保持在折叠基底处。第三周开始进行不对称分裂，有增殖后代向上移动。直到第四周结束，在褶皱尖端才观察到凋亡细胞。分泌细胞散布在折叠基底的增殖细胞之间，在第三和第四周数量增加，同时增殖模式发生变化。
斑马鱼胚胎后肠上皮的发育包括 2 周的缓慢增殖，然后是 2 周的变态形成到成年结构。发育动力学 2019。© 2019 威利父子公司
