Hobmayer B, Rentzsch F, Kuhn K, Happel C M, von Laue C C, Snyder P, Rothbächer U, Holstein T W
Department of Molecular Cell Biology, Zoological Institute, Darmstadt University of Technology, Germany.
Nature. 2000 Sep 14;407(6801):186-9. doi: 10.1038/35025063.
Members of the Wnt/wingless family of secreted proteins act as short-range inducers and long-range organizers during axis formation, organogenesis and tumorigenesis in many developing tissues. Wnt signalling pathways are conserved in nematodes, insects and vertebrates. Despite its developmental significance, the evolutionary origin of Wnt signalling is unclear. Here we describe the molecular characterization of members of the Wnt signalling pathway--Wnt, Dishevelled, GSK3, beta-Catenin and Tcf/Lef--in Hydra, a member of the evolutionarily old metazoan phylum Cnidaria. Wnt and Tcf are expressed in the putative Hydra head organizer, the upper part of the hypostome. Wnt, beta-Catenin and Tcf are transcriptionally upregulated when head organizers are established early in bud formation and head regeneration. Wnt and Tcf expression domains also define head organizers created by de novo pattern formation in aggregates. Our results indicate that Wnt signalling may be involved in axis formation in Hydra and support the idea that it was central in the evolution of axial differentiation in early multicellular animals.
分泌蛋白的Wnt/无翅家族成员在许多发育组织的轴形成、器官发生和肿瘤发生过程中作为短程诱导剂和长程组织者发挥作用。Wnt信号通路在 nematodes、昆虫和脊椎动物中是保守的。尽管其具有发育意义，但Wnt信号的进化起源尚不清楚。在这里，我们描述了Wnt信号通路成员——Wnt、散乱蛋白、糖原合成酶激酶3、β-连环蛋白和Tcf/Lef——在水螅中的分子特征，水螅是进化上古老的后生动物门刺胞动物门的成员。Wnt和Tcf在假定的水螅头部组织者——口道的上部表达。当在芽形成和头部再生早期建立头部组织者时，Wnt、β-连环蛋白和Tcf的转录上调。Wnt和Tcf的表达域也定义了通过聚集体中的从头模式形成产生的头部组织者。我们的结果表明，Wnt信号可能参与了水螅的轴形成，并支持了它在早期多细胞动物轴向分化进化中起核心作用的观点。
