Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Team Solves Mystery Associated with DNA Repair

Published: Wednesday, December 19, 2012
Last Updated: Wednesday, December 19, 2012
Bookmark and Share
Every time a human or bacterial cell divides it first must copy its DNA. Specialized proteins unzip the intertwined DNA strands while others follow and build new strands, using the originals as templates.

Whenever these proteins encounter a break – and there are many – they stop and retreat, allowing a new cast of molecular players to enter the scene.

Scientists have long sought to understand how one of these players, a repair protein known as RecA in bacterial cells, helps broken DNA find a way to bridge the gap. They knew that RecA guided a broken DNA strand to a matching sequence on an adjoining bit of double-stranded DNA, but they didn’t know how. In a new study, researchers report they have identified how the RecA protein does its job.

“The puzzle for scientists has been: How does the damaged DNA look for and find its partner, the matching DNA, so that it can repair itself?” said University of Illinois physics professor Taekjip Ha, who led the study. “Because the genomic DNA is millions of bases long, this task is much like finding a needle in a haystack. We found the answer to how the cell does this so quickly.”

The research is described in a paper in eLife, a new open-access journal supported by the Howard Hughes Medical Institute (HHMI), the Max Planck Society and the Wellcome Trust. Ha is an HHMI investigator. The National Science Foundation provided primary funding for this work.

DNA repair is vital to health, vitality and longevity. Disruptions of the process can lead to the early onset of diseases associated with aging or cancer in animals. The breast cancer mutation known as BRCA2, for example, disrupts a gene involved in loading Rad51 (the human equivalent of RecA) onto a broken DNA strand to begin the process of repair.

Previous studies have shown that in bacteria, RecA forms a filament that winds itself around a broken, single strand of DNA. Like a matchmaker trying to find a partner for an unpaired dancer, it scours the corresponding DNA strands for a sequence that will pair up perfectly with the broken strand. Once it finds the sequence, the broken strand steps in and chemically bonds to its new partner, displacing one of the unbroken strands (which eventually pairs with the other broken strand). This elaborate molecular square dance allows the cell to go back to the work of duplicating its genome. Each broken strand now is paired with an unbroken one, and uses the intact strand as a template for replication. (Watch an animation about this process.)

“If a break in DNA occurs, you have to repair it,” Ha said. “We wanted to know how RecA helps the DNA find a sequence complementary to it in the sea of genomic DNA, and how it does it so quickly.”

To answer this question, the researchers made use of fluorescence resonance energy transfer (FRET) to observe in real time the interaction of the RecA protein and the DNA. FRET uses fluorescent molecules whose signals vary in intensity depending on their proximity to one another. By labeling a single DNA strand bound by RecA and putting a different fluorescent label on a stretch of double-stranded DNA, the researchers could see how the molecules interacted with one another.

The team determined that RecA that is bound to a broken, single-stranded DNA molecule actually slides back and forth along the double-stranded DNA molecule searching for a match.

“We discovered that this RecA filament can slide on double-stranded DNA for a span of sequences covering about 200 base pairs of DNA,” Ha said. “This is how one strand of DNA can be exchanged with another from a different DNA duplex. That’s the process called
‘recombination.’ ”

The discovery explains how DNA repair can occur so quickly, Ha said.

“We did a calculation that found that without this kind of process that we discovered, then DNA repair would be 200 times slower,” he said. “So your DNA would not be repaired quickly and damage would accumulate, possibly leading to serious diseases.”


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 2,900+ scientific posters on ePosters
  • More Than 4,200+ 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

Shedding New Light on Biological Molecules and Cells
An interdisciplinary research team at Illinois has developed a new material composite derived from quantum dots.
Thursday, January 07, 2016
Cancer-Fighting Tomato Component Traced
The metabolic pathway associated with lycopene, the bioactive red pigment found in tomatoes, has been traced by researchers at the University of Illinois.
Monday, November 16, 2015
Brightness-Equalized Quantum Dots Improve Biological Imaging
Researchers have introduced a new class of light-emitting quantum dots (QDs) with tunable and equalized fluorescence brightness across a broad range of colors. This results in more accurate measurements of molecules in diseased tissue and improved quantitative imaging capabilities.
Monday, October 05, 2015
Genome Mining Effort Discovers 19 New Natural Products in Four Years
Each of these products is a potential new drug. One of them has already been identified as an antibiotic.
Friday, September 11, 2015
First Artificial Ribosome Designed
Researchers at the University of Illinois at Chicago and Northwestern University have engineered a tethered ribosome that works nearly as well as the authentic cellular component, or organelle, that produces all the proteins and enzymes within the cell.
Friday, July 31, 2015
Epigenetic Switches that turn Stem Cells into Blood Vessel Cells Uncovered
Researchers at the University of Illinois have identified a molecular mechanism that directs embryonic stem cells to mature into endothelial cells.
Monday, June 29, 2015
Carbon Nanoparticles you can Make at Home
Researchers have found an easy way to produce carbon nanoparticles that are small enough to evade the body’s immune system, reflect light in the near-infrared range for easy detection, and carry payloads of pharmaceutical drugs to targeted tissues.
Friday, June 19, 2015
Crop-rotation Resistant Rootworms Have A Lot Going on in Their Guts
After decades of effort, scientists are finally figuring out how insects develop resistance to environmentally friendly farming practices – such as crop rotation – that are designed to kill them.
Thursday, June 11, 2015
How TALENs Find Their Way Around the Genome
Scientists from the University of Illinois Urbana-Champaign have discovered how a genome editing technology finds its way to a specific location in the genome.
Thursday, June 04, 2015
Epigenetic Hangover
New research hints at the long term effects of teenage binge drinking on a genetic level.
Tuesday, May 26, 2015
Surveys Miss Majority Of Poisonings, Underestimate Cost By Billions
Health surveys may underestimate the number of poisonings in the United States by 60 percent to 90 percent, according to a report in the journal Clinical Toxicology by University of Illinois at Chicago researchers.
Wednesday, April 15, 2015
Molecule-making Machine Simplifies Complex Chemistry
Chemists built the machine to assemble complex small molecules at the click of a mouse.
Thursday, March 19, 2015
Microtubes Create Cozy Space For Neurons To Grow
Illinois researchers developed a platform to grow and study neuron cells using tiny rolled microtubes.
Friday, November 14, 2014
Some Plants Regenerate by Duplicating their DNA
A plant’s ability to duplicate its genome within individual cells influences its ability to regenerate.
Thursday, November 13, 2014
Team Discovers How Microbes Build a Powerful Antibiotic
Researchers discovery opens up new avenues of research into thousands of similar molecules.
Wednesday, October 29, 2014
Scientific News
Retractable Protein Nanoneedles
The ability to control the transfer of molecules through cellular membranes is an important function in synthetic biology; a new study from researchers at Harvard’s Wyss Institute for Biologically Inspired Engineering and Harvard Medical School (HMS) introduces a novel mechanical method for controlling release of molecules inside cells.
Leukemia’s Surroundings Key to its Growth
Researchers at The University of Texas at Austin have discovered that a type of cancer found primarily in children can grow only when signaled to do so by other nearby cells that are noncancerous.
Common Cell Transformed into Master Heart Cell
By genetically reprogramming the most common type of cell in mammalian connective tissue, researchers at the University of Wisconsin—Madison have generated master heart cells — primitive progenitors that form the developing heart.
‘Smelling’ Prostate Cancer
A research team from the University of Liverpool and the University of the West of England (UWE Bristol) has reached an important milestone towards creating a urine diagnostic test for prostate cancer that could mean that invasive diagnostic procedures that men currently undergo eventually become a thing of the past.
Genetic Mutation that Prevents Diabetes Complications
The most significant complications of diabetes include diabetic retinal disease, or retinopathy, and diabetic kidney disease, or nephropathy. Both involve damaged capillaries.
A Crystal Clear View of Biomolecules
Fundamental discovery triggers paradigm shift in crystallography.
Could the Food we Eat Affect Our Genes?
Almost all of our genes may be influenced by the food we eat, according to new research.
NIH Seeks Research Applications to Study Zika in Pregnancy, Developing Fetus
Institute has announced that the new effort seeks to understand virus effect on reproduction and child development.
Iron in the Blood Could Cause Cell Damage
Concentrations of iron similar to those delivered through standard treatments can trigger DNA damage within 10 minutes, when given to cells in the laboratory.
Criminal Justice Alcohol Program Linked to Decreased Mortality
Institute has announced that in the criminal justice alcohol program deaths dropped by 4.2 percent over six years.
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
2,900+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,200+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!