Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
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 2,500+ 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

Tumor-suppressing Gene Lends Insight to Cancer Treatment
Researchers have found that delicate replication process derails if a gene named PTEN has mutated or is absent.
Tuesday, July 14, 2015
Synthetic Immune Organ Produces Antibodies
Cornell engineers have created a functional, synthetic immune organ that produces antibodies and can be controlled in the lab, completely separate from a living organism.
Friday, June 12, 2015
On Planes, Savory Tomato Becomes Favored Flavor
Study shows the effect that airplane noise has on passengers' taste preferences.
Friday, May 15, 2015
$5.5M NSF Grant Aims to Improve Rice Crops with Genome Editing
Researchers to precisely target, cut, remove and replace DNA in a living cell to improve rice.
Friday, May 08, 2015
'Shield' Gives Tricky Proteins a New Identity
Solubilization of Integral Membrane Proteins with high Levels of Expression.
Saturday, April 11, 2015
DNA Safeguard May Be Key In Cancer Treatment
Cornell researchers have developed a new technique to understand the actions of key proteins required for cancer cells to proliferate.
Monday, March 09, 2015
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
Bacteria Be Gone!
New technology keeps bacteria from sticking to surfaces.
Monday, January 19, 2015
On the Environmental Trail of Food Pathogens
Learning where Listeria dwells can aid the search for other food pathogens.
Tuesday, December 23, 2014
Chemists Show That ALS is a Protein Aggregation Disease
Using a technique that illuminates subtle changes in individual proteins, chemistry researchers at Cornell have uncovered new insight into the underlying causes of Amyotrophic Lateral Sclerosis (ALS).
Thursday, October 23, 2014
Genetics Used to Improve Plants for Bioenergy
An upcoming genetics investigation into the symbiotic association between soil fungi and feedstock plants for bioenergy production could lead to more efficient uptake of nutrients, which would help limit the need for expensive and polluting fertilizers.
Thursday, August 28, 2014
Computer Model Reveals Cancer's Energy Source
Findings focused on the energy-making process in cancer cells known as the Warburg Effect.
Tuesday, August 19, 2014
A New Player in Lipid Metabolism Discovered
Specially engineered mice gained no weight, and normal counterparts became obese on the same high-fat, obesity-inducing Western diet.
Monday, August 18, 2014
Ingested Nanoparticles May Damage Liver
Although nanoparticles in food, sunscreen and other everyday products have many benefits, researchers from Cornell are finding that at certain doses, the particles might cause human organ damage.
Tuesday, August 12, 2014
Foodborne Pathogen Detection Speeds Up Dramatically
Next-generation sequencing techniques allow rapidly identification of strains of salmonella, quickening responses to potential outbreaks.
Monday, July 21, 2014
Scientific News
The Changing Tides of the In Vitro Diagnostics Market
With the increasing focus in personalized medicine, diagnostics plays a crucial role in patient monitoring.
LaVision BioTec Reports on the Neuro Research on the Human Brain After Trauma
Company reports on the work of Dr Ali Ertürk from the Institute for Stroke and Dementia Research at LMU Munich.
NIH Study Shows No Benefit of Omega-3 Supplements for Cognitive Decline
Research was published in the Journal of the American Medical Association.
Less May Be More in Slowing Cholera Epidemics
Mathematical model shows more cases may be prevented and more lives saved when using one dose of cholera vaccine instead of recommended two doses.
Investigating the Vape
Expert independent review concludes that e-cigarettes have potential to help smokers quit.
NIH Launches Human RSV Study
Study aims to understand infection in healthy adults to aid development of RSV medicines, vaccines.
Researchers Discover Synthesis of a New Nanomaterial
Interdisciplinary team creates biocomposite for first time using physiological conditions.
Poor Survival Rates in Leukemia Linked to Persistent Genetic Mutations
For patients with an often-deadly form of leukemia, new research suggests that lingering cancer-related mutations – detected after initial treatment with chemotherapy – are associated with an increased risk of relapse and poor survival.
Flu Remedies Help Combat E. coli Bacteria
Physiologists from the University of Zurich have now discovered why the intestinal bacterium Escherichia coli (E. coli) multiplies heavily and has an inflammatory effect.
Marijuana Genome Unraveled
A study by Canadian researchers is providing a clearer picture of the evolutionary history and genetic organization of cannabis, a step that could have agricultural, medical and legal implications for this valuable crop.
Scroll Up
Scroll Down
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
2,500+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!