Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A matter of force

04.05.2007
Researchers work out the mechanics of asymmetric cell division

When a cell divides, normally the result is two identical daughter cells. In some cases however, cell division leads to two cells with different properties. This is called asymmetric cell division and plays an important role in embryonic development and the self-renewal of stem cells. Researchers from the European Molecular Biology Laboratory (EMBL) have now worked out the mechanism underlying asymmetric cell division in nematode worms. The study, which is published in the current issue of Cell, reveals that interactions between the mitotic spindle and the cell cortex are crucial for asymmetric division.

Soon after the egg cell has been fertilized, the developing embryo of the nematode worm Caenorhabditis elegans undergoes its first cell division. The division gives rise to a bigger cell at the anterior end of the embryo, where the head will develop, and a smaller cell at the posterior end. For this asymmetric division to take place, the mitotic spindle, the apparatus that separates a cell’s chromosomes, needs to be located not centrally but towards the posterior of the egg. The cellular structures that make sure the spindle gets to the right place are protein filaments called microtubules. They are dynamic structures that constantly grow and shrink by adding on or taking off individual building blocks.

“Just before cell division the mitotic spindle moves towards the posterior of the cell while oscillating up and down,” says François Nédélec, group leader at EMBL. “We wanted to find out the mechanisms of this motion and explore its properties.”

Nédélec and his group combined computer simulations with microscopy studies to test the predictions made about microtubule behaviour experimentally. This approach revealed that the interaction of the microtubules forming the mitotic spindle and the cell cortex, a structure lining the cell just beneath the plasma membrane, most likely brings about the correct positioning of the spindle towards the posterior of the cell. The microtubules grow until they reach the borders of the cell and touch the cortex. Upon contact with the cortex, the filaments immediately start to shrink.

“This shrinkage is then translated into a pulling force at the cortex,” says Cleopatra Kozlowski from Nédélec’s group, who carried out the research together with Martin Srayko from the Max Planck Institute of Molecular Cell Biology and Genetics. “How exactly this works we don’t know yet. One possibility could be that part of the cortex holds on to the microtubule while it shortens, and so pulls on the whole spindle.”

The nature of so-called force generators on the cortex is yet unclear, as is the question if more of them are active at the posterior to give more net force in that direction. But computer simulations show that the concept of force generators that translate the dynamic behaviour of microtubules into a pulling force can explain the specific movements of the mitotic spindle.

The same principle might apply also to asymmetric cell division in other organisms and contexts, such as stem cell renewal. The cellular components involved in such divisions have been conserved throughout evolution making it likely that different species might also share the mechanism of the process.

Anna-Lynn Wegener | alfa
Further information:
http://www.embl.org/aboutus/news/press/2007/04may07/index.html

Further reports about: Cortex asymmetric microtubule mitotic posterior spindle

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

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 Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>