Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Heads or tails?

Worm with abundant ability to regenerate relies on ancient gene to make decisions

Most people don't think worms are cool. But the tiny flatworm that Northwestern University scientist Christian Petersen studies can do something very cool indeed: it can regenerate itself from nearly every imaginable injury, including decapitation. When cut in half, it becomes two worms.

This amazing ability of the planarian flatworm to regenerate its entire body from a small wedge of tissue has fascinated scientists since the late 1800s. The worms can regrow any missing cell or tissue -- muscle, neurons, epidermis, eyes, even a new brain.

Now Petersen and colleague Peter Reddien of the Massachusetts Institute of Technology (MIT) have discovered that an ancient and seldom-studied gene is critical for regeneration in these animals. The findings may have important ramifications for tissue regeneration and repair in humans.

The gene, called notum, plays a key role in the regeneration decision-making process. Protein from this gene determines whether a head or tail will regrow at appropriate amputation sites, the researchers found.

"These worms are superstars in regeneration, and we want to learn how they restore missing body parts," said Petersen, an assistant professor of molecular biosciences in Northwestern's Weinberg College of Arts and Sciences. "We anticipate that understanding the details of how regeneration occurs in nature will ultimately have a broad impact on the repair of human tissue."

The study is published in the May 13 issue of the journal Science. Petersen, a former postdoctoral fellow in Reddien's lab, is the first author. Reddien, associate professor of biology at MIT and the Whitehead Institute for Biomedical Research, is the other author.

The ability of planarians to regenerate any missing tissues after injury depends on a pool of adult stem cells. Researchers hope that by studying this worm they will understand the molecular processes that naturally allow stem cell-mediated tissue repair in higher animals.

In their paper, Petersen and Reddien show that the gene notum is critical for head regeneration in planarians. Inactivation of notum caused animals to regenerate a tail instead of a head, creating two-tailed animals.

"Injuries can alter tissues in many different ways, so regenerating animals must have robust systems that specify restoration of appropriate structures," Petersen said. "Our results suggest that the animals 'decide' what needs to be regenerated, in part, by using cues that indicate axis direction with respect to the wound."

Planarians are 2 to 20 millimeters in size and have a complex anatomy with around a million cells. They live in freshwater ponds and streams around the world. The worm's genome has been sequenced, and its basic biology is well-characterized, making planarians popular with scientists.

Petersen and Reddien also found that notum controls a widely used biochemical circuit, Wnt signaling, in order to promote proper regeneration. This ancient signaling circuit operates in all animals and controls many processes in development and disease, including tissue repair and cancer progression.

In the paper, the authors describe how the gene notum acts at head-facing 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 head-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. (It takes the worm about a week to regrow a head or tail.)

The researchers 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," Reddien said. "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."

The name of the paper is "Polarized Activation of Notum at Wounds Inhibits Wnt Signaling to Promote Planarian Head Regeneration."

Megan Fellman | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>