Yasugi Sadao, Takeda Hiroyuki, Fukuda Kimiko
Zoological Institute, Faculty of Science, University of Tokyo, Hongo, Bunkyo, Tokyo 113, Japan.
Dev Growth Differ. 1991 Jun;33(3):235-241. doi: 10.1111/j.1440-169X.1991.00235.x.
The endodermal epithelia of esophagus, proventriculus and gizzard of 6-day chicken embryos can form glands and express embryonic chicken pepsinogen (ECPg), when they are subjected to the influence of proventricular mesenchyme, while intestinal epithelium of the same age cannot respond to the inductive influence of proventricular mesenchyme. We attempted in this paper to know whether this regional difference of epithelia to respond to mesenchymal influence originates very early in development or it is established gradually in the course of development of digestive tract. The young presumptive intestinal endoderm taken from embryos having 15-20 somites was associated and cultivated with 6-day proventricular mesenchyme. The presumptive intestinal endoderm never expressed ECPg although it formed gland-like structures. In the control explants composed of presumptive stomach endoderm and proventricular mesenchyme, glands were formed and gland cells expressed ECPg detected by immunocytochemistry and in situ hybridization. These results indicate that the developmental fate of presumptive intestinal endoderm is determined rather strictly at very early developmental stage, and suggest that the segregation of at least two cell lineages occurs early in the development; one which can express ECPg under the influence of proventricular mesenchyme, and another one which cannot express ECPg and differentiates mainly into intestinal epithelium.
6日龄鸡胚的食管、前胃和肌胃的内胚层上皮在受到前胃间充质的影响时可形成腺体并表达胚胎型鸡胃蛋白酶原（ECPg），而同龄的肠上皮则不能对前胃间充质的诱导影响作出反应。在本文中，我们试图了解上皮对间充质影响作出反应的这种区域差异是在发育早期就已产生，还是在消化道发育过程中逐渐形成的。从具有15 - 20对体节的胚胎中取出的假定肠内胚层与6日龄的前胃间充质联合培养。尽管假定肠内胚层形成了腺样结构，但从未表达过ECPg。在由假定胃内胚层和前胃间充质组成的对照外植体中，形成了腺体，腺细胞通过免疫细胞化学和原位杂交检测到表达了ECPg。这些结果表明，假定肠内胚层的发育命运在发育早期就相当严格地被确定了，这表明至少两种细胞谱系在发育早期就发生了分离；一种在受到前胃间充质影响时能表达ECPg，另一种则不能表达ECPg，主要分化为肠上皮。
