Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Polarized notum Activation at Wounds Inhibits Wnt Function to Promote Planarian Head Regeneration
Christian P. Petersen1,*, and
Peter W. Reddien1,2,3,
Abstract:
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.
1 Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA. 2 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02138, USA. 3 Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815, USA.
* Present address: Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
To whom correspondence should be addressed. E-mail: reddien{at}wi.mit.edu
The editors suggest the following Related Resources on Science sites:
In Science Magazine
PERSPECTIVES
Jonathan M. W. Slack (13 May 2011) Science332 (6031), 799.
[DOI: 10.1126/science.1206913] |Summary »|Full Text »|PDF »
PBX/extradenticle is required to re-establish axial structures and polarity during planarian regeneration.
R. A. Blassberg, D. A. Felix, B. Tejada-Romero, and A. A. Aboobaker (2013)
Development
140, 730-739
|Abstract »|Full Text »|PDF »
pbx is required for pole and eye regeneration in planarians.
C.-C. G. Chen, I. E. Wang, and P. W. Reddien (2013)
Development
140, 719-729
|Abstract »|Full Text »|PDF »
Regulated tissue fluidity steers zebrafish body elongation.
A. K. Lawton, A. Nandi, M. J. Stulberg, N. Dray, M. W. Sneddon, W. Pontius, T. Emonet, and S. A. Holley (2013)
Development
140, 573-582
|Abstract »|Full Text »|PDF »
Notum Homolog Plays a Novel Role in Primary Motor Innervation.
J. A. Cantu, G. P. Flowers, and J. Topczewski (2013)
J. Neurosci.
33, 2177-2187
|Abstract »|Full Text »|PDF »
Follistatin antagonizes Activin signaling and acts with Notum to direct planarian head regeneration.
To whom correspondence should be addressed. E-mail: 
