Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers unravel DNA tangles and enzyme seamstresses

15.03.2006


Almost three metres of tightly-coiled DNA strands fit into a cell’s nucleus. As DNA replicates, the strands unwind and unfold and then re-package into chromosomes, the genetic blueprints of life – but what happens if this process becomes entangled?

Untangling the heaps of DNA strings during cell division is the job of special enzymes called topoisomerases. How they achieve this feat may be simpler than previously thought, says U of T research. In a study published in the current online issue of Biophysical Journal, researchers used computer simulations to mimic the DNA mess inside the nucleus with a series of billions of linked and unlinked loops. Their calculations indicated that whether DNA molecules are interlinked is shown by the way they touch each other.

Interlinked DNA loops tend to touch in an easily recognizable hook-like way, fitting together perfectly; whereas strands of unlinked DNA molecules tend to curve away when they touch each other. The findings could have implications in designing new drugs to treat cancer and infectious diseases as uncontrolled DNA linking and tangling often result in cell death.



"The exciting part is that these seemingly abstract physical principles we work with can be useful some day to tie up DNA in cancer cells and kill them off," says U of T biochemist Hue Sun Chan, the study’s co-author and a Canada Research Chair in proteomics, bioinformatics and functional genomics.The study is co-authored by Professor Lynn Zechiedrich of Baylor College of Medicine in Houston, Texas, who proposed the notion in an earlier conceptual report, and the lead author, Zhirong Liu, is a U of T postdoctoral fellow in Chan’s research group. "These are the same general principles that can be applied to other areas of science and engineering to address various entanglement problems," Chan says.

The curved distinctions between DNA strands may allow the seamstresses of the process -- the topoisomerases -- to identify linked DNA loops, cut a strand apart, let another strand pass through, and then reconnect the cut strand so that DNA can separate into untangled lengths that are the chromosomes: the topoisomerases only have to cut and reconnect at hooked-like but not other touching points. If this process were disrupted, however, the cell would be in serious trouble. "One link could keep the cell from dividing. Two links are even more lethal," says Zechiedrich, who notes that "the results of these computer simulations are very striking."

While Chan and his collaborators stress their results represent only a quantitative proof of concept, they do see the finding as particularly relevant for understanding diseases such as cancer, where cell multiplication goes haywire. "Besides further elucidating the principles we found, what needs to be done now is to test these findings experimentally and ultimately apply them to real-life cell division and target the developmental processes that lead to disease."

Karen Kelly | EurekAlert!
Further information:
http://www.utoronto.ca

More articles from Life Sciences:

nachricht Fingerprint' technique spots frog populations at risk from pollution
27.03.2017 | Lancaster University

nachricht Parallel computation provides deeper insight into brain function
27.03.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University

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

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>