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. Author manuscript; available in PMC: 2012 Jul 1.
Published in final edited form as: Trends Genet. 2011 Jun 15;27(7):277–285. doi: 10.1016/j.tig.2011.04.004

Figure 1. RNAi studies have identified genes required for guiding tissue identity in regeneration and tissue turnover in adult planarians.

Figure 1

(A) Schematic of planarian depicting visible body regions and animal axes. Red lines indicate amputation planes approximately utilized to generate animals cartooned in part B. (B) Left, decrease in Wnt signaling components, such as following RNAi of β-catenin-1, cause regeneration of two heads whereas increase in Wnt signaling (with APC RNAi) or increase in Hedgehog signaling (with patched RNAi) cause regeneration of two tails [41–44, 96, 97]. Middle and right, schematized phenotypes are assessed with anatomical markers using in situ hybridizations. Middle, nou darake RNAi causes regeneration of ectopic brain cells (purple) and eyes (adapted from [52]). Right, decrease in BMP signaling causes ventralization of regeneration blastemas (normally ventral neurons are depicted in purple) [56–58]. Side views are depicted with ventral to the left. Red lines indicate amputation planes, white areas depict regeneration blastemas and pigmented areas depict pre-existing tissues. (C) Left, β-catenin-1 RNAi causes intact animals to develop ectopic heads around the periphery. Middle, ectopic brain cells appear progressively more posterior in intact nou darake(RNAi) animals. Right, inhibition of BMP signaling components with RNAi causes intact animals to develop normally ventral structures (such as brain and nerve cords, purple) on their dorsal sides (see part B for references).