Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Finding sheds new light into mysterious process of cell movement during development

15.08.2002


Biologists at Vanderbilt and the University of Missouri have uncovered what could be a major clue into the mysterious molecular processes that direct cells to the correct locations within a developing embryo.



Understanding the molecular basis of these processes, and how they can go wrong, may ultimately lead to treatments for many birth defects, such as spina bifida that afflicts between 800 to 1,000 babies born each year in the United States.

Writing in the August issue of the scientific journal Nature Cell Biology, the researchers report the discovery that a single protein facilitates the movements of cells within the developing embryo of the zebrafish, a small fish that has become an important animal model for studying the development of vertebrates, animals with backbones.


The researchers report that this protein plays an essential role in directing the migration of cells within the spherical egg to the head-tail axis where the body is beginning to take shape. They also found that disruption of the same protein inhibits the normal migration of nerve cells within the developing zebrafish brain, a type of motion found in human brain development.

"A great deal is known about the movement of the projections that neurons send out to connect with other neurons, but very little is known about how neurons move from one place to another," says Lilianna Solnica-Krezel, the associate professor of biological sciences at Vanderbilt who led the study with Anand Chandrasekhar, assistant professor of biological sciences at the University of Missouri, Columbia.

Zebrafish have characteristics that make them ideal for developmental research. They lay eggs that are transparent and develop outside the body, making them particularly easy to study. Development is also rapid, proceeding from fertilization to hatching in only three days. The fish are also easy and inexpensive to raise, so scientists can keep thousands of them in a laboratory. The zebrafish genome is currently being sequenced, which allows researchers to employ the powerful tools of genomics to unravel the complex molecular processes involved in development.

One of these methods is to examine the impact of specific mutations. In this case, Solnica-Krezel and her colleagues were exploring what takes place in a mutant called trilobite. (It was given this name because the developing egg forms a pattern shaped like one of these prehistoric marine creatures.) During an early stage of development called gastrulation, the cells begin converging from all sides of the spherical egg to the embryonic axis where the body begins to form. What begins as a disordered, chaotic motion changes into an orderly movement. As this happens the cells also change from a round to an elongated, spindle shape.

"It’s something like a mob transforming into an army," says Solnica-Krezel.

Her research group discovered that the trilobite mutations prevent the army from forming. Cell motions continue to be disordered and do not develop the same sense of direction and purpose in the mutant as they do in normal embryos. As a result, trilobite’s development is stunted. The scientists determined that the mutations disrupt the activity of a specific membrane protein, called either Strabismus or Van Gogh.

The same protein has previously been identified in the development of the fruit fly, Drosophila melanogaster, where it affects the orientation of cells that form the fly’s wings and compound eyes. A closely related protein found in mice is implicated in malformation of the neural tube, the tubular structure that develops into the brain and spinal cord.

Somewhat later in zebrafish development, a number of motor neurons move from one part of the brain to another. "We don’t understand why they move because they can form the connections they need from their original location," says Solnica-Krezel. But Chandrasekhar and his Missouri team discovered that this movement does not take place in trilobite embryos.

In order to determine whether the neurons’ failure to migrate was due to factors within the cell or the extracellular environment, the researchers transplanted trilobite neurons in the brains of normal embryos and normal neurons in trilobite brains. They found that none of the normal motor neurons migrated when placed in a trilobite brain, whereas a third of the trilobite neurons migrated when placed in normal brains. This led the scientists to conclude that the Strabismus/Van Gogh protein must have both cellular and extracellular effects.

With further study, the researchers determined that the neurons’ method of movement was similar to that of an amoeba: they extend their bodies in the direction they want to move and retract them from the opposite side. By labeling the nerve cells with fluorescent protein, the biologists determined that the trilobite cells moved much slower and their movements were more random in nature than normal neurons.

The results of their various tests suggest that the protein Strabismus/Van Gogh acts independently in mediating neuron movement. If this proves to be the case, then it provides "an entry point to elucidate the molecular basis of this class of neuronal migration," they conclude in the article.


Solnica-Krezel’s research team included graduate student Florence Marlow along with research associates Jason R. Jessen, Jacek Topczewski and Diane S. Sepich. Graduate student Stephanie Bingham worked with Chandrasekhar. The research was funded by the National Institutes of Health, the National Science Foundation and the Pew Scholars Program in the Biomedical Sciences.

David F. Salisbury | EurekAlert!
Further information:
http://exploration.vanderbilt.edu

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>