Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Skeleton for Chromosomes

26.08.2013
Jan-Michael Peters and his team at the Research Institute of Molecular Pathology (IMP) found that the structure of Chromosomes is supported by a kind of molecular skeleton, made of cohesin. Their discovery is published in the current issue of the journal NATURE.

Every single cell in the human body contains an entire copy of the genetic blueprint, the DNA. Its total length is about 3.5 meters and all of it has to fit into the cell’s nucleus, just one-hundredth of a millimeter in diameter.


Artistic interpretation of fluorescent light micrographs of Wapl depleted nuclei which show cohesin vermicelli. The nuclei have been pseudo-colored and scaled to different sizes. IMP

Blown up in proportion, this would equal the task of squeezing a 150km long string into a soccer ball. Just how the cell manages to wrap up its DNA so tightly is still poorly understood.

One way of compacting DNA is achieved by coiling it tightly around histone-proteins. This mechanism has been studied in detail and is the focus of an entire discipline, Epigenetics. However, simple organisms such as bacteria have to manage their DNA-packaging without histones, and even in human cells histones probably cannot do the job on their own.

A new role for an old molecule

A team of scientists at the Research Institute of Molecular Pathology (IMP) in Vienna can now present evidence for an additional mechanism involved in structuring DNA. Managing Director Jan-Michael Peters and his research group discovered that a protein-complex named cohesin has a stabilizing effect on DNA. In evolutionary terms, cohesin is very old and its structure has hardly changed over billions of years. It was present long before histones and might therefore provide an ancient mechanism in shaping DNA.

Cell biologists are already familiar with cohesin and its role in cell division. The protein-complex is essential for the correct distribution of chromosomes to daughter cells. It forms a molecular ring that keeps sister-chromatids together until the precise moment when segregation takes place. This function and the molecular structure of cohesin have been discovered by IMP-scientists in 1997.

Antonio Tedeschi, a postdoc in the group of Jan-Michael Peters, has now found evidence that cohesin supports the architecture of DNA in non-dividing (interphase) cells. He analyzed cells in which he had shut down the function of Wapl. This protein controls how tightly cohesin binds to DNA. Without Wapl, cohesin is ‘locked’ onto chromatin in an unusually stable state. As a consequence, cells are unable to express their genes correctly and cannot divide.

Vermicelli keep DNA in shape

When he analyzed Wapl-depleted cells under the microscope, Tedeschi found elongated structures that he called “vermicelli” (Italian for small worms). Since one vermicello is present for each chromosome, he concluded that its function is to keep chromosomes in shape, rather like a skeleton.

“We think that the vermicelli are the ‘bones’ of interphase chromosomes”, says Jan-Michael Peters. “Just like our bodies depend on the bones for support, the cells depend very much on cohesin to retain their structure.”

The importance of the cohesin-system becomes obvious in cases where it is impaired. Several rare congenital diseases have been linked to mutations in the respective gene. The faulty structure of the cohesin molecule causes severe developmental retardation and is a serious medical condition. There are no causal therapies available at present.

Original publication: Wapl is an essential regulator of chromatin structure and chromosome segregation. Antonio Tedeschi et al. Doi: 10.1038/nature12471

About the IMP
The Research Institute of Molecular Pathology (IMP) in Vienna is a basic biomedical research institute largely sponsored by Boehringer Ingelheim. With over 200 scientists from 30 nations, the IMP is committed to scientific discovery of fundamental molecular and cellular mechanisms underlying complex biological phenomena. Research areas include cell and molecular biology, neurobiology, disease mechanisms and computational biology.
Contact
Dr. Heidemarie Hurtl
IMP Communications
Dr. Bohr Gasse 7
1030 Vienna, Austria
Tel.: (+43 1) 79730 3625
Mobile: (+43 1) 664 8247910
hurtl@imp.ac.at
Scientific Contact:
Dr. Jan-Michael Peters
jan-michael.peters@imp.ac.at

Dr. Heidemarie Hurtl | idw
Further information:
http://www.imp.ac.at

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome 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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>