Reim Gerlinde, Mizoguchi Takamasa, Stainier Didier Y, Kikuchi Yutaka, Brand Michael
MPI of Molecular Cell Biology and Genetics, and Department of Genetics, TU Dresden, Pfotenhauerstrasse 108, D-01309 Dresden, Germany.
Dev Cell. 2004 Jan;6(1):91-101. doi: 10.1016/s1534-5807(03)00396-4.
The gastrulating vertebrate embryo develops three germlayers: ectoderm, mesoderm, and endoderm. Zebrafish endoderm differentiation starts with the activation of sox17 by casanova (cas). We report that spg (pou2/Oct4) is essential for endoderm formation. Embryos devoid of maternal and zygotic spg function (MZspg) lack endodermal precursors. Cell transplantations show that spg acts in early endodermal precursors, and cas mRNA-injection into MZspg embryos does not restore endoderm development. spg and cas together are both necessary and sufficient to activate endoderm development, and stimulate expression of a sox17 promoter-luciferase reporter. Endoderm and mesoderm derive from a common origin, mesendoderm. We propose that Spg and Cas commit mesendodermal precursors to an endodermal fate. The joint control of endoderm formation by spg and cas suggests that the endodermal germlayer may be a tissue unit with distinct genetic control, thus adding genetic support to the germlayer concept in metazoan development.
外胚层、中胚层和内胚层。斑马鱼的内胚层分化始于卡萨诺瓦（cas）对sox17的激活。我们报告称，spg（pou2/Oct4）对于内胚层的形成至关重要。缺乏母源和合子spg功能的胚胎（MZspg）缺少内胚层前体。细胞移植表明spg在内胚层早期前体中发挥作用，并且将cas mRNA注射到MZspg胚胎中并不能恢复内胚层的发育。spg和cas共同作用对于激活内胚层发育而言既是必要的也是充分的，并且能刺激sox17启动子 - 荧光素酶报告基因的表达。内胚层和中胚层起源于共同的中内胚层。我们提出Spg和Cas使中内胚层前体定向分化为内胚层命运。spg和cas对内胚层形成的联合控制表明，内胚层胚层可能是一个具有独特遗传控制的组织单位，从而为后生动物发育中的胚层概念增添了遗传学支持。
