DNA repair mechanisms relocate in response to stress

Mar 26, 2009

Like doctors making house calls, some DNA repair enzymes can relocate to the part of the cell that needs their help, a collaborative team of scientists at Emory University School of Medicine has found.

The signal that prompts relocation is oxidative , an imbalance of cellular metabolism connected with several human diseases.

The study integrated the expertise of three Emory groups and resulted in a new level of understanding of the cell's response to genetic damage. The finding could lead to new targets for anti-cancer drugs that interfere with DNA repair, says Paul Doetsch, PhD, professor of biochemistry, radiation oncology, and hematology and oncology at Emory University School of Medicine.

The results were published in the February 1 issue of Molecular and Cellular Biology. The journal's editors chose an image of yeast with fluorescent DNA for the cover.

" and oxidative stress are very closely related," Doetsch says. "For example, the way radiation inflicts most of its damage on DNA is through oxidative stress. The more we know about how cells respond to oxidative stress, the more chances there could be to influence those responses for diagnostic or therapeutic purposes."

The DNA inside cells is continually under assault by heat, radiation and oxygen. Cells have an extensive set of repair enzymes that comb through DNA, continually excising and re-copying damaged segments. To complicate matters, mitochondria (cells' miniature power plants) have their own DNA.

Working with Doetsch, Emory graduate students Lyra Griffiths and Dan Swartzlander, and biochemists Anita Corbett and Keith Wilkinson, genetically modified strains of yeast so that two different DNA repair enzymes would be fluorescent. They were able to follow the enzymes around the cell when yeast was exposed to hydrogen peroxide, causing oxidative stress, or to other chemicals causing DNA damage.

One they studied, Ntg1, moves to the nucleus or the mitochondria depending on where DNA damage is concentrated, the authors found. In contrast, a related enzyme, Ntg2, stays in the nucleus under all conditions.

Cells appear to direct Ntg1's relocation by briefly attaching a small protein called SUMO to what needs to be moved around, the authors found. SUMO is found in fungi, plants and animals and is already being investigated by several research groups as a possible target for anti-cancer drugs.

Source: Emory University (news : web)

Explore further: Researchers successfully clone adult human stem cells

add to favorites email to friend print save as pdf

Related Stories

Misreading of damaged DNA may spur tumor formation

Nov 20, 2008

The DNA in our cells is constantly under assault from oxygen, the sun's radiation and environmental stresses. Most of the time, our cells can repair the damage before it gets copied into a permanent mutation that could lead ...

New step in DNA damage response in neurons discovered

Jan 18, 2009

Researchers have identified a biochemical switch required for nerve cells to respond to DNA damage. The finding, scheduled for advance online publication in Nature Cell Biology, illuminates a connection between proteins involv ...

A new way to look at lung cancer and tobacco carcinogens

May 28, 2008

Two types of cancer-causing agents in cigarettes—a nicotine-derived chemical and polycyclic aromatic hydrocarbons (PAHs) are the main culprits in lung cancer. Exposure to tobacco smoke – both mainstream ...

Recommended for you

Researchers successfully clone adult human stem cells

Apr 18, 2014

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Researchers develop new model of cellular movement

Apr 18, 2014

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

For resetting circadian rhythms, neural cooperation is key

Apr 17, 2014

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

User comments : 0

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.