PDF(Pubmed)
Abstract：
Lamprey homologues of the classic embryonic inducer Noggin are similar in expression pattern and functional properties to Noggin homologues of jawed vertebrates. All noggin genes of vertebrates apparently originated from a single ancestral gene as a result of genome duplications. nogginA, nogginB and nogginC of lampreys, like noggin1 and noggin2 of gnathostomes, demonstrate the ability to induce complete secondary axes with forebrain and eye structures when overexpressed in Xenopus laevis embryos. According to current views, this finding indicates the ability of lamprey Noggin proteins to suppress the activity of the BMP, Nodal/Activin and Wnt/beta-catenin signaling pathways, as shown for Noggin proteins of gnathostomes. In this work, by analogy with experiments in Xenopus embryos, we attempted to induce secondary axes in the European river lamprey Lampetra fluviatilis by injecting noggin mRNAs into lamprey eggs in vivo. Surprisingly, unlike what occurs in amphibians, secondary axis induction in the lampreys either by noggin mRNAs or by chordin and cerberus mRNAs, the inductive properties of which have been described, was not observed. Only wnt8a mRNA demonstrated the ability to induce secondary axes in the lampreys. Such results may indicate that the mechanism of axial specification in lampreys, which represent jawless vertebrates, may differ in detail from that in the jawed clade.
摘要：
经典胚胎诱导剂Noggin的七叶鱼同源物在表达模式和功能特性上与颌骨脊椎动物的Noggin同源物相似。由于基因组重复，脊椎动物的所有noggin基因显然都起源于一个祖先基因。noggina,七叶鱼的nogginB和nogginC，像noggin1和noggin2一样，证明了在非洲爪狼胚胎中过表达时，能够诱导前脑和眼睛结构完整的次级轴。根据目前的观点,这一发现表明七叶鱼Noggin蛋白抑制BMP活性的能力，Nodal/激活素和Wnt/β-catenin信号通路,如颌骨造口术的Noggin蛋白所示。在这项工作中,类似于非洲爪狼胚胎的实验，我们试图通过将nogginmRNA注入体内的七叶鱼卵中，在欧洲七叶鱼中诱导次生轴。令人惊讶的是,与两栖动物不同，通过nogginmRNAs或chordin和cerberusmRNAs诱导lamp。已经描述了其感应特性，没有被观察到。只有wnt8amRNA显示出在七翅目中诱导次级轴的能力。这些结果可能表明，七叶鱼轴向规格的机理，代表无颚脊椎动物，在细节上可能与下颚进化枝不同。
