Nutritional endoderm in a direct developing frog: A potential parallel to the evolution of the amniote egg
Nutritional endoderm in a direct developing frog: A potential parallel to the evolution of the amniote egg
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DOI：
10.1002/dvdy.21153
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发表时间：
2007-05-01
影响因子：
2.5
通讯作者：
Elinson, Richard P.
中科院分区：
文献类型：
--
作者：
Buchholz, Daniel R.;Singamsetty, Srikanth;Elinson, Richard P.
直接发育的青蛙Eleutherodactylus coqui的卵的体积是两栖动物模式动物非洲爪蟾的20倍。卵大小的增加导致了营养内胚层的起源，营养内胚层是一种提供营养但不分化成消化道组织的新型细胞类型。作为E.当coqui内胚层发育时，在分化的肠细胞和大的卵黄细胞之间存在明显的界限，即使卵黄血小板耗尽，这种界限也会持续存在。卵黄细胞不会成为消化道的组织，并且会丢失，如组织学和谱系追踪所示。然而，内胚层转录因子EcSox 17不能区分这两种细胞类型。当卵黄细胞的卵裂被抑制时，胚胎发生继续，表明可以容忍一定程度的不完全卵裂。E. coqui可能与3.6亿年前大西洋鲑鱼卵进化过程中发生的变化相似。发展动力学236.1259-1272，2007年。(C)2007 Wiley-Liss，Inc.
The egg of the direct-developing frog, Eleutherodactylus coqui, has 20x the volume as that of the model amphibian, Xenopus laevis. Increased egg size led to the origin of nutritional endoderm, a novel cell type that provides nutrition but does not differentiate into digestive tract tissues. As the E. coqui endoderm develops, a distinct boundary exists between differentiating intestinal cells and large yolky cells, which persists even when yolk platelets are depleted. The yolky cells do not become tissues of the digestive tract and are lost, as shown by histology and lineage tracing. EcSox17, an endodermal transcriptional factor, did not distinguish these two cell types, however. When cleavage of the yolky cells was inhibited, embryogenesis continued, indicating that some degree of incomplete cleavage can be tolerated. The presence of cellularized nutritional endoderm in E. coqui may parallel changes that occurred in the evolution of the amniote egg 360 million years ago. Developmental Dynamics 236.1259-1272, 2007. (C) 2007 Wiley-Liss, Inc.