Corporate Banner
Satellite Banner
Genotyping & Gene Expression
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Physicists Tease out Twisted Torques of DNA

Published: Monday, July 01, 2013
Last Updated: Monday, July 01, 2013
Bookmark and Share
Like an impossibly twisted telephone cord, DNA, the molecule that encodes genetic information, also often finds itself twisted into coils.

This twisting, called supercoiling, is caused by enzymes that travel along DNA’s helical groove and exert force and torque as they move.

For the first time, these tiny torques have been measured in the lab of Michelle Wang, professor of physics and Howard Hughes Medical Institute investigator. Using an instrument called an angular optical trap (AOT), Wang and colleagues have reported direct measurements of the torque generated by the motor protein, E. coli RNA polymerase (RNAP), as it traverses supercoiled DNA. Their technique may be used to examine the broader impacts of torque and DNA supercoiling associated with other motor proteins, and lend new insights into the gene transcription process.

The work was published online June 27 in the journal Science, with first author Jie Ma, Cornell postdoctoral associate, and Lu Bai, former graduate student and now an assistant professor at Penn State.

DNA supercoiling is an important regulator of gene expression, but it has been hard to study because of the minute torque involved, Wang said. Using the AOT, the researchers not only recreated DNA supercoiling, but also measured, to piconewton-nanometer precision, the torque being generated by the polymerase.

The AOT uses a nanofabricated quartz cylinder as a “handle” that “holds” one end of a DNA strand and is sensitive to the torque exerted on the cylinder. The torque they measured is about 10 piconewton-nanometers, only about 1/1022 of a typical torque applied by a torque wrench, but enough to have substantial influence on many biological processes at the molecular level.

“To measure very, very small twists and torques on biomolecules is very challenging,” said Wang, whose lab has spent about 10 years developing the technology. “It’s easier to twist something than to measure how much twist you’re exerting. Our instrument lets us do both.”

The researchers also observed how torque regulates the speed of RNAP as it transcribes DNA; a resistive torque slowed RNAP and caused it to pause occasionally.

They further determined that the torque generated by RNAP was sufficient to cause DNA strand separation, i.e., melting, which pointed to the robust and strong nature of RNAP as a torsional motor protein. It also pointed to the potential role of RNAP to facilitate initiation of adjacent promoters, bind regulatory proteins and  initiate DNA replication.

Lastly, they discovered that transcribing RNAP was resilient to torque fluctuations that were quick – less than a second in duration. These results introduce a much clearer understanding of how DNA supercoiling regulates gene transcription – a window into a previously unseen world.

The study is titled “Transcription Under Torsion.” The work was supported by the National Science Foundation, the Howard Hughes Medical Institute and the National Institutes of Health.


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,400+ scientific posters on ePosters
  • More than 3,700+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

A ‘STAR’ is Born: Engineers Devise Genetic 'On' Switch
A new “on” switch to control gene expression has been developed by Cornell scientists.
Tuesday, February 03, 2015
DNA Editor Named Runner-up Breakthrough of 2012
A discovery that allows life scientists to precisely edit genomes for everything from crop and livestock improvement to human gene and cell therapy was named runner-up for Science magazine's 2012 Breakthrough of the Year.
Wednesday, February 27, 2013
Gene Thought to be Linked to Alzheimer's is Marker for Only Mild Impairment
Defying the widely held belief that a specific gene is the biggest risk factor for Alzheimer's disease, report says that people with that gene are more likely to develop mild cognitive impairment -- but not Alzheimer's.
Monday, February 18, 2013
Scientific News
Oxitec ‘Self-Limiting Gene’ Offers Hope for Controlling Invasive Moth
A new pesticide-free and environmentally-friendly way to control insect pests has moved ahead with the publication of results showing that Oxitec diamondback moths (DBM) with a ‘self-limiting gene’ can dramatically reduce populations of DBM.
Teeth Reveal Lifetime Exposures to Metals, Toxins
Researchers have identified dental biomarkers to reveal links between early iron exposure and late life brain diseases.
Scientists Identify Schizophrenia’s “Rosetta Stone” Gene
Scientists have identified a critical function of what they believe to be schizophrenia’s “Rosetta Stone” gene that could hold the key to decoding the function of all genes involved in the disease.
Could a simple saliva test detect Alzheimer's?
Researchers have presented findings suggesting that a simple, non-invasive diagnostic for Alzheimer's could be within reach.
New Research Advances Genetic Studies in Wildlife Conservation
‘Next-gen’ DNA sequencing of non-invasively collected hair expands field of conservation genetics.
AncestryDNA and Calico to Research the Genetics of Human Lifespan
Collaboration will analyze family history and genetics to facilitate development of cutting-edge therapeutics.
Gene Variation Identified for Teen Binge-Eating
Researchers have identified a gene variant which can lead to teenage binge eating, they hope that their work will inform the development of future preventative measures.
Adaptimmune's Novel Cancer Therapeutics Show Positive Clinical Trial Results
The company has announced that positive data from its Phase I/II study of its affinity enhanced T-cell receptor (TCR) therapeutic targeting the NY-ESO-1 cancer antigen in patients with multiple myeloma has been published.
Gene Testing Now Allows Precision Medicine for Thoracic Aneurysms
Researchers at the Aortic Institute at Yale have tested the genomes of more than 100 patients with thoracic aortic aneurysms, a potentially lethal condition, and provided genetically personalized care.
Facebook for the Proteome
Researchers have developed a network for describing protein-protein interactions that can then be used to examine protein interactions that may have biological or clinical significance.
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,400+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!