Duboc Véronique, Röttinger Eric, Besnardeau Lydia, Lepage Thierry
UMR 7009 Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Observatoire Océanologique, 06230 Villefranche-sur-Mer, France.
Dev Cell. 2004 Mar;6(3):397-410. doi: 10.1016/s1534-5807(04)00056-5.
In the sea urchin embryo, the oral-aboral axis is specified after fertilization by mechanisms that are largely unknown. We report that early sea urchin embryos express Nodal and Antivin in the presumptive oral ectoderm and demonstrate that these genes control formation of the oral-aboral axis. Overexpression of nodal converted the whole ectoderm into oral ectoderm and induced ectopic expression of the orally expressed genes goosecoid, brachyury, BMP2/4, and antivin. Conversely, when the function of Nodal was blocked, by injection of an antisense Morpholino oligonucleotide or by injection of antivin mRNA, neither the oral nor the aboral ectoderm were specified. Injection of nodal mRNA into Nodal-deficient embryos induced an oral-aboral axis in a largely non-cell-autonomous manner. These observations suggest that the mechanisms responsible for patterning the oral-aboral axis of the sea urchin embryo may share similarities with mechanisms that pattern the dorsoventral axis of other deuterostomes.
在海胆胚胎中，受精后口-反口轴的特化机制在很大程度上尚不清楚。我们报告称，早期海胆胚胎在假定的口外胚层中表达Nodal和Antivin，并证明这些基因控制口-反口轴的形成。Nodal的过表达将整个外胚层转化为口外胚层，并诱导口表达基因goosecoid、brachyury、BMP2/4和Antivin的异位表达。相反，当通过注射反义吗啉代寡核苷酸或注射Antivin mRNA来阻断Nodal的功能时，口外胚层和反口外胚层均未特化。将nodal mRNA注射到缺乏Nodal的胚胎中，以一种很大程度上非细胞自主的方式诱导了口-反口轴的形成。这些观察结果表明，负责海胆胚胎口-反口轴模式形成的机制可能与其他后口动物背腹轴模式形成的机制具有相似性。
