Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers shed light on shrinking of chromosomes

11.06.2007
Late shortening of chromosomes helps cells to organise and protect their DNA during cell division

A human cell contains an enormous 1.8 metres of DNA partitioned into 46 chromosomes. These have to be copied and distributed equally into two daughter cells at every division. Condensation, the shortening of chromosomes, allows the cell to handle such huge amounts of genetic material during cell division and helps preventing fatal defects in chromosome separation. Now researchers from the European Molecular Biology Laboratory (EMBL) for the first time tracked chromosome condensation in mammalian cells over the entire course of cell division. In this week’s advanced online publication of Nature Cell Biology they report crucial new insights into timing, function and molecular basis of chromosome condensation.

What happens when chromosomes are not correctly separated and distributed during cell division we know very well; two daughter cells with either broken chromosomes or different numbers of chromosomes result and severe diseases including cancer can arise. But so far we know only little about condensation, a process crucial to the successful separation of chromosomes. Using powerful microscopes, researchers led by Jan Ellenberg at EMBL looked at living mammalian cells to find out how and when chromosomes shorten during cell division.

Condensation begins early, when the cell starts preparing for division, and the chromosomes become shorter and shorter until they are about to separate and migrate towards the poles of the cell.

... more about:
»Researchers »Separation »condensation »defects

“It is at this stage that textbooks say chromosomes are shortest. Then, after separating they would expand again,” says Ellenberg. “But we found something very different. Shortly after they finish separating, chromosomes actually condense even further. This makes sense, because in this way they are shortest when the physical division of one cell body into two takes place. Like this, no long chromosome arms extend over the plane of division, because that could expose the DNA to serious mechanical damage.”

The extreme condensation of chromosomes towards the end of cell division can also serve as a safety net if something goes wrong with chromosome separation in earlier phases of division. When the researchers added chemicals to the cell to block the late condensation, more separation defects appeared.

“Sometimes chromosomes get stuck and cannot be fully separated by the spindle that normally distributes them into the daughter cells,” says Felipe Mora-Bermúdez, who carried out the experiments in Ellenberg’s lab, “we think that the ‘super condensation’ at later stages helps to disentangle such chromosomes and acts as a back-up mechanism to rescue separation defects.”

The EMBL researchers found that an enzyme called Aurora kinase is crucially involved in this process. Blocking this enzyme abolishes late condensation of chromosomes. They now hope to uncover the detailed molecular mechanism underlying the late shortening of chromosomes. This could further advance our understanding of cell division and the risk factors that lead to defects in chromosome separation and their dramatic consequences.

Anna-Lynn Wegener | alfa
Further information:
http://www.embl.org/aboutus/news/press/2007/10jun07/

Further reports about: Researchers Separation condensation defects

More articles from Life Sciences:

nachricht When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short
23.03.2017 | Institut für Pflanzenbiochemie

nachricht WPI team grows heart tissue on spinach leaves
23.03.2017 | Worcester Polytechnic Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

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

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>