Navigation Links
Researchers unravel DNA tangles and enzyme seamstresses

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 lo ops, 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."


'"/>

Source:University of Toronto


Related biology news :

1. Researchers discover way to make cells in the eye sensitive to light
2. Researchers find how protein allows insects to detect and respond to pheromones
3. Researchers Uncover Key Step In Manufacture of Memory Protein
4. Researchers reveal the infectious impact of salmon farms on wild salmon
5. Researchers identify target for cancer drugs
6. Researchers discover molecule that causes secondary stroke
7. Researchers find missing genes of ancient organism
8. Researchers trace evolution to relatively simple genetic changes
9. Researchers add new tool to tumor-treatment arsenal
10. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
11. VCU Researchers Identify Networks Of Genes Responding To Alcohol In The Brain
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:11/30/2016)...  higi SH llc (higi) announced today the ... brands, industry thought-leaders and celebrity influencers looking to ... taking steps to live healthier, more active lives. ... has built the largest self-screening health station network ... who have conducted over 185 million biometric screenings.  ...
(Date:11/24/2016)... Calif. , Nov. 23, 2016 Cercacor ... endurance athletes and their trainers non-invasively measure ... Index, Pulse Rate, and Respiration Rate in approximately 30 ... enables users easy and immediate access to key data ... part of a training regimen. Hemoglobin ...
(Date:11/17/2016)... Market Watch: Primarily supported by ownership types; Private ... market is to witness a value of US$37.1 billion by ... Annual Growth Rate (CAGR) of 10.75% is foreseen from ... North America is not way behind ... at 9.56% respectively. Report Focus: The ...
Breaking Biology News(10 mins):
(Date:12/2/2016)... ... December 01, 2016 , ... ... Nanowear on their recent FDA Class II 510(k) clearance for their flagship medical ... in commercializing remote cardiac monitoring devices that rely on cloth-based nanosensors. While other ...
(Date:12/2/2016)... ... December 02, 2016 , ... Robots will storm the Prudential Center in ... 2016. The event, which is held on the United Nations International Day of Persons ... back into the workplace. Suitable Technologies is partnering with NTI to showcase how technology ...
(Date:12/2/2016)... The immunohistochemistry (IHC) market is projected to reach USD ... the forecast period of 2016 to 2021 dominated by immunohistochemistry (IHC) ... largest share of immunohistochemistry (IHC) market, by end user.   ... , , ... 225 pages, profiling 10 companies and supported with 181 tables and ...
(Date:11/30/2016)... ... November 30, 2016 , ... ... Voice Coil Actuator with a flexure design that ensures high alignment accuracy by ... pricing and is ideally suited where extreme precision is required, such as in ...
Breaking Biology Technology: