Process may explain why damaged DNA contributes to cancer and other age-related illnesses
As we and other vertebrates age, our DNA accumulates mutations and becomes rearranged, which may result in a variety of age-related illnesses, including cancers.
Biologists Vera Gorbunova and Andei Seluanov have now discovered one reason for the increasing DNA damage: the primary repair process begins to fail with increasing age and is replaced by one that is less accurate.
The findings have been published in the journal PLOS Genetics.
"Scientists have had limited tools to accurately study how DNA repair changes with age," said Gorbunova. "We are now able to measure the efficiency with which cells in mice of different ages repair DNA breaks at the same place in the chromosome."
Gorbunova explained that when mice are young, the breaks in DNA strands are repaired through a process called non-homologous end joining (NHEJ), in which the damage is repaired by gluing the DNA together with no or very little overlap.
However, Gorbunova and Seluanov found that NHEJ began to fail as the mice got older, allowing a less reliable DNA repair process—microhomology-mediated end joining (MMEJ)—to take over. With MMEJ repairs, broken ends are glued together by overlapping similar sequences that are found within the broken DNA ends. This process leads to loss of DNA segments and the wrong pieces being stitched together.
Gorbunova and her team were able to make their observations by working with genetically-modified mice whose cells produce green fluorescent protein (GFP) that glows each time the breaks are repaired. By tracking how many cells glowed green in different tissues, the researchers determined the efficiency of repair.
"We showed two things with these genetically-modified mice," said Gorbunova. "Not only did the efficiency of DNA repair decline with age, but the mice began using a sloppier repair mechanism, leading to more mutations, particularly in the heart and lungs."
DNA breaks occur frequently because animal cells are under constant assault from routine activities in the environment—whether by a blast of X-rays from a visit to the doctor or simply breathing in oxygen—and, as a result, the DNA molecules often get damaged.
Using the genetically modified mice, the research team can now look at how diet, medicines, and different genetic factors also affect DNA repair in mice.
"These mice may very well help us devise novel ways to prevent some of the illnesses associated with aging," said Gorbunova.
Peter Iglinski | Eurek Alert!
New way to look at cell membranes could change the way we study disease
19.11.2018 | University of Oxford
Controlling organ growth with light
19.11.2018 | European Molecular Biology Laboratory
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
19.11.2018 | Materials Sciences
19.11.2018 | Information Technology
19.11.2018 | Life Sciences