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 Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University

nachricht Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>