Polarized notum Activation at Wounds Inhibits Wnt Function to Promote Planarian Head Regeneration
Author(s)Petersen, Christian Paul; Reddien, Peter
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Regeneration requires initiation of programs tailored to the identity of missing parts. Head-versus-tail regeneration in planarians presents a paradigm for study of this phenomenon. After injury, Wnt signaling promotes tail regeneration. We report that wounding elicits expression of the Wnt inhibitor notum preferentially at anterior-facing wounds. This expression asymmetry occurs at essentially any wound, even if the anterior pole is intact. Inhibition of notum with RNA interference (RNAi) causes regeneration of an anterior-facing tail instead of a head, and double-RNAi experiments indicate that notum inhibits Wnt signaling to promote head regeneration. notum expression is itself controlled by Wnt signaling, suggesting that regulation of feedback inhibition controls the binary head-tail regeneration outcome. We conclude that local detection of wound orientation with respect to tissue axes results in distinct signaling environments that initiate appropriate regeneration responses.
DepartmentMassachusetts Institute of Technology. Department of Biology
American Association for the Advancement of Science (AAAS)
Petersen, C. P. and Reddien, P. W. "Polarized notum Activation at Wounds Inhibits Wnt Function to Promote Planarian Head Regeneration." Science 332, 6031 (May 2011): 852-855 © 2011 American Association for the Advancement of Science
Author's final manuscript