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 Lethal combination: Drug cocktail turns off the juice to cancer cells
12.12.2018 | Universität Basel

nachricht Smelling the forest – not the trees
12.12.2018 | Universität Konstanz

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 Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Innovative Infrared heat reduces energy consumption in coating packaging for food

12.12.2018 | Trade Fair News

New Foldable Drone Flies through Narrow Holes in Rescue Missions

12.12.2018 | Information Technology

Obtaining polyester from plant oil

12.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>