PT  - JOURNAL ARTICLE
AU  - Duffy, David J.
AU  - Plickert, Günter
AU  - Kuenzel, Timo
AU  - Tilmann, Wido
AU  - Frank, Uri
TI  - Wnt signaling promotes oral but suppresses aboral structures in <em>Hydractinia</em> metamorphosis and regeneration
AID  - 10.1242/dev.046631
DP  - 2010 Sep 15
TA  - Development
PG  - 3057--3066
VI  - 137
IP  - 18
4099  - http://dev.biologists.org/content/137/18/3057.short
4100  - http://dev.biologists.org/content/137/18/3057.full
SO  - Development2010 Sep 15; 137
AB  - We studied the role of Wnt signaling in axis formation during metamorphosis and regeneration in the cnidarian Hydractinia. Activation of Wnt downstream events during metamorphosis resulted in a complete oralization of the animals and repression of aboral structures (i.e. stolons). The expression of Wnt3, Tcf and Brachyury was upregulated and became ubiquitous. Rescue experiments using Tcf RNAi resulted in normal metamorphosis and quantitatively normal Wnt3 and Brachyury expression. Isolated, decapitated polyps regenerated only heads but no stolons. Activation of Wnt downstream targets in regenerating animals resulted in oralization of the polyps. Knocking down Tcf or Wnt3 by RNAi inhibited head regeneration and resulted in complex phenotypes that included ectopic aboral structures. Multiple heads then grew when the RNAi effect had dissipated. Our results provide functional evidence that Wnt promotes head formation but represses the formation of stolons, whereas downregulation of Wnt promotes stolons and represses head formation.