Corporate Banner
Satellite Banner
Genomics
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

Join For Free

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 3,500+ scientific posters on ePosters
  • More than 5,000+ 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
$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
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
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
For Cancer Patients, Sugar-Coated Cells are Deadly
Paszek’s lab will focus on developing high-resolution microscopy to further study cell membrane-related cancer mechanisms.
Friday, June 27, 2014
Shark, Human Proteins are Surprisingly Similar
Despite widespread fascination with sharks, the world’s oldest ocean predators have long been a genetic mystery.
Friday, December 06, 2013
Gold-Plated Nano-Bits Find, Destroy Cancer Cells
Scientists have merged tiny gold and iron oxide particles, then added antibody guides to steer them through the bloodstream toward colorectal cancer cells.
Monday, October 21, 2013
Using Genes to Rescue Animal and Plants from Extinction
With estimates of losing 15 to 40 percent of the world’s species over the next four decades researchers whether science should employ genetic engineering to the rescue.
Friday, September 27, 2013
Dad’s Genes Build Placentas
Though placentas support the fetus and mother, it turns out that the organ grows according to blueprints from dad.
Monday, August 12, 2013
Expelled DNA that Traps Toxins May Backfire in Obese
The body’s most powerful immune cells may have a radical way of catching their prey that could backfire on people who are overweight.
Wednesday, June 19, 2013
Genetic Switches Play Big Role in Human Evolution
Study offers further proof that the divergence of humans from chimpanzees was profoundly influenced by mutations to DNA sequences.
Wednesday, June 12, 2013
Genome Offers Clues to Amphibian-Killing Fungus
A fungus that has decimated amphibians globally is much older than previously thought.
Thursday, May 30, 2013
Scientists Find Clues to Some Inherited Heart Diseases
Cornell researchers have uncovered the basic cell biology that helps explain heart defects found in diseases known as laminopathies.
Tuesday, May 07, 2013
Scientists Develop World's Smallest Drug Deliverer
Cornell researchers have created a pore in “Cornell Dots” – brightly glowing nanoparticles nicknamed C-Dots – that can carry medicine.
Friday, April 12, 2013
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
Scientific News
A Diversity of Genomes
New DNA from understudied groups reveals modern genetic variation, ancient population shifts.
Gene Could Reduce Female Mosquitoes
Virginia Tech researchers have found a gene that can reduce female mosquitoes over many generations.
Improving Crop Efficiency with CRISPR
New study of CRISPR-Cas9 technology from Virginia Tech shows potential to improve crop efficiency.
Examining mtDNA May Help Identify Unknown Ancestry That Influences Breast Cancer Risk
Researchers studying mtDNA in a group of triple negative breast cancer patients found that 13 percent of participants were unaware of ancestry that could influence their risk of cancer.
Bacteria Use Ranking Strategy to Fight Off Viruses
Researchers have explained why microbes store virus confrontation information sequentially, with most recent attacks first.
Gene Therapy Technique May Help Prevent Cancer Metastasis
Gene-regulating RNA molecules could help treat early-stage breast cancer tumors before they spread.
Enhancing Antibiotics to Defeat Resistant Bacteria
Scientists enhance ability of antibiotics to defeat resistant types of bacteria using molecules called PPMOs
The Genetics of Blood Pressure
Researchers have identifed areas of the genome associated with blood-pressure including 17 previously unknown loci.
Mosquito Genetics Determine Tastes
Study reveals mosuito's preference for human versus animal biting is determined by genetics.
Quadruple Helix DNA Aids Cancer Therapies
Researchers have identified the role that a four-stranded version of DNA may play in the role of cancer progression.
Skyscraper Banner

SELECTBIO Market Reports
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
3,500+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
5,000+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!