RELEVANCE: Like the Wnt signaling pathway, notum is highly conserved throughout species, from sea anenomes to fruit flies to humans, but little is known about its activity. The role of notum in regulating the Wnt signaling pathway in regeneration may indicate a relationship that is found in other animals as well.
A seldom-studied gene known as notum plays a key role in the planarian’s regeneration decision-making process, according to Whitehead Institute scientists. Protein from this gene determines whether a head or tail will regrow at appropriate amputation sites.
Since the late 1800s, scientists have been fascinated by the planarian’s amazing ability to regenerate its entire body from a small wedge of tissue. Whitehead Member Peter Reddien and former postdoctoral fellow Christian Petersen recently found that the Wnt pathway—an ancient signaling circuit that operates in all animals—inhibits head regeneration at wound sites in the tiny flatworms. Intriguingly, Petersen and Reddien also noticed that wounding triggers activation of a Wnt gene at injury sites that normally regenerate a head, suggesting that something else must determine whether a wound makes a head or a tail.
In a paper published in the May 13 issue of Science, authors Christian Petersen and Peter Reddien describe how the gene notum acts at head-facing (anterior) wounds as a dimmer switch to dampen the Wnt pathway and promote head regeneration. When the head or tail of a planarian is cut off, Wnt is activated. This Wnt activity turns on notum, but only at anterior-facing wounds. In a feedback loop, notum then turns Wnt down low enough that it can no longer prevent a head from forming. In tail-facing wounds, however, notum is not activated highly, a condition that promotes tail regrowth.
“These results suggest that animals ‘decide’ what needs to be regenerated, in part, by using cues that indicate axis direction with respect to the wound,” says first author Petersen, who is a former postdoctoral fellow in the Reddien lab and currently Assistant Professor of Molecular Biosciences at Northwestern University. “It’s telling us that for the head/tail decision, proper regeneration requires sensing and responding to tissue orientation at wound sites.”
Petersen and Reddien are intrigued by this new role for notum. Like the Wnt signaling pathway, notum is highly conserved throughout species, from sea anenomes to fruit flies to humans, but little is known about its roles in biology. Because both notum and the Wnt signaling pathway are so evolutionarily ancient, their interaction in planarians may indicate a relationship that is important in other animals as well.
“We anticipate that this phenomenon of feedback inhibition regulating the levels of Wnt activity will be seen broadly in other biological contexts,” says Reddien, who is also an Associate Professor of Biology at MIT and a Howard Hughes Medical Institute (HHMI) Early Career Scientist. “Wnt signaling is so broadly studied and important in biology, including for tissue repair and regeneration. notum isn't really on the map for the broad roles Wnt signaling plays in tissue repair, but this work demonstrates the central role it can play.”
This research was supported by the National Institutes of Health (NIH), the American Cancer Society (ACS), and the Keck Foundation.
Peter Reddien’s primary affiliation is with Whitehead Institute for Biomedical Research, where his laboratory is located and all his research is conducted. He is also a Howard Hughes Medical Institute Early Career Scientist and an associate professor of biology at Massachusetts Institute of Technology.
“Polarized activation of notum at wounds inhibits Wnt signaling to promote planarian head regeneration”
Science, May 13, 2011.
Christian P. Petersen (1,4) and Peter W. Reddien (1,2,3)1. Whitehead Institute for Biomedical Research, Cambridge, MA 02142
Nicole Giese | Newswise Science News
Make way for the mini flying machines
21.03.2018 | American Chemical Society
New 4-D printer could reshape the world we live in
21.03.2018 | American Chemical Society
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
21.03.2018 | Life Sciences
21.03.2018 | Trade Fair News
20.03.2018 | Physics and Astronomy