Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Heads or tails? Scientists identify gene that regulates polarity in regenerating flatworms

10.12.2007
When cut, a planarian flatworm can use a population of stem cells called neoblasts to regenerate new heads, new tails or even entire new organisms from a tiny fragment of its body.

Mechanisms have been sought to explain this process of regeneration polarity for over 100 years, but until now, little was known about how planaria can regenerate heads and tails at their proper sites.

Scientists in the lab of Whitehead Member Peter Reddien have discovered that the gene Smed-beta-catenin-1 is required for proper decisions about head-versus-tail polarity in regenerating flatworms. Their results were published in the December 6 issue of Science Express online.

Reddien’s lab studies regeneration in the planarian Schmidtea mediterranea. “Evolution has selected for mechanisms that allow organisms to accomplish incredible feats of regeneration,” and planaria offer a dramatic example, notes Reddien, who is also an assistant professor of biology at Massachusetts Institute of Technology. “By developing this model system to explore the molecular underpinnings of regeneration, we now have a better understanding of the molecular underpinnings of the process.”

The researchers used a technique called RNA interference (RNAi) to screen a group of genes known to be involved in animal development, in order to study the signaling mechanisms that regulate whether the animal would produce a head or tail during regeneration.

“We discovered that inhibiting the gene Smed-beta-catenin-1 caused animals to regenerate a head instead of a tail at the site of the wound,” says Christian Petersen, Whitehead postdoctoral fellow and lead author on the paper. “This resulted in a worm that possessed two oppositely facing heads. Smed-beta-catenin-1 is the first gene found to be required for this regeneration polarity.”

Genes very similar to Smed-beta-catenin-1 are found in animals ranging from jellyfish to humans, and they have been implicated in posterior tissue specification in frogs, sea urchins and many other animals.

Beta-catenin proteins are signaling molecules that reside in the cell’s cytoplasm, and are known to turn on important developmental genes when a cell is exposed to a secreted protein in the Wnt family.

The researchers thus went on to study the expression of Wnt genes during regeneration, and found that different members of the gene family were active at different locations across the planarian’s head-to-tail axis. These results suggest that Smed-beta-catenin-1 may be active in the tail region and inhibited in the head region by the regulated expression of these Wnt genes.

The finding suggests that these varied Wnt genes regulate Smed-beta-catenin-1 activity to provide the positional information by which the organism specifies the location of its head and tail during regeneration. These results could help to explain how other regenerating animals “know” what missing tissues to make.

Additionally, researchers found that Smed-beta-catenin-1 plays a role in ongoing cell replacement in planaria that have not been challenged to regenerate. When the gene was inhibited, these animal’s tails began changing into heads.

The researchers hope that future work on regeneration polarity and Smed-beta-catenin-1 will yield a better understanding of the molecular mechanisms of regeneration.

Cristin Carr | EurekAlert!
Further information:
http://www.wi.mit.edu

Further reports about: Regeneration Smed-beta-catenin-1 Wnt flatworm planaria polarity regenerate regenerating

More articles from Life Sciences:

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Heavy nitrogen molecules reveal planetary-scale tug-of-war

20.11.2017 | Earth Sciences

Taking a spin on plasma space tornadoes with NASA observations

20.11.2017 | Physics and Astronomy

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>