Staehling-Hampton K, Hoffmann F M, Baylies M K, Rushton E, Bate M
McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706.
Nature. 1994;372(6508):783-6. doi: 10.1038/372783a0.
Inductive interactions between germ layers are an essential feature of the development of many organisms. In several species these interactions are mediated by members of the transforming growth factor-beta (TGF beta) family. In amphibians, different concentrations of activin can induce different types of mesoderm in the animal cap assay. In Drosophila, a member of the TGF beta family, decapentaplegic (dpp), acts as an inductive signal. Midway through embryogenesis, dpp is expressed in the visceral mesoderm, and enhances the expression of the homeotic gene labial in the underlying midgut endoderm. Earlier in development, however, dpp expression is limited to the dorsal ectoderm. At this stage in development, thickveins, a dpp receptor, is expressed in the mesoderm, and this suggests that ectodermal dpp might not only be required for development of dorsal ectoderm, but could also act inductively to mediate pattern formation in the underlying mesoderm. Here we show, by expressing dpp ectopically in the ectoderm and mesoderm and by examining dpp null mutant embryos, that dpp regulates expression of mesodermal genes.
胚层之间的诱导相互作用是许多生物体发育的一个基本特征。在几个物种中，这些相互作用是由转化生长因子-β（TGF-β）家族的成员介导的。在两栖动物中，不同浓度的激活素在动物帽实验中可诱导不同类型的中胚层。在果蝇中，TGF-β家族的一个成员，即果蝇的“脱五体不全”基因（dpp），起着诱导信号的作用。在胚胎发育中期，dpp在内脏中胚层表达，并增强其下方中肠内胚层中同源异型基因唇（labial）的表达。然而，在发育早期，dpp的表达仅限于背侧外胚层。在这个发育阶段，dpp受体“粗脉”（thickveins）在中胚层表达，这表明外胚层的dpp可能不仅是背侧外胚层发育所必需的，而且还可能通过诱导作用介导其下方中胚层的模式形成。在这里，我们通过在外胚层和中胚层中异位表达dpp以及检查dpp基因敲除突变体胚胎，证明dpp调节中胚层基因的表达。
