Navigation Links
New paper describes how DNA avoids damage from UV light
Date:7/31/2014

BOZEMAN, Mont. In the same week that the U.S. surgeon general issued a 101-page report about the dangers of skin cancer, researchers at Montana State University published a paper breaking new ground on how DNA the genetic code in every cell responds when exposed to ultraviolet (UV) light.

The findings advance fundamental understanding of DNA damage by the UV rays found in sunlight. This damage can lead to skin cancer, aging and some degenerative eye diseases.

"Our paper advances foundational knowledge about how DNA responds to UV radiation. In our experiments, we observe the earliest events immediately after DNA is energized by UV radiation. These events determine whether or not DNA is damaged," said one of the paper's co-authors, Bern Kohler, an MSU professor in the Department of Chemistry and Biochemistry.

DNA is built like a staircase and carries genetic instructions that are unique to each person. It's very hardy and generally able to stand up to ultraviolet rays, but UV rays sometimes cause mutations. UV exposure is a major cause of skin cancer, and while there are nearly 5 million cases of skin cancer each year in the U.S. alone and 9,000 related deaths the numbers would be far worse if DNA were more easily damaged.

"UV is actually very damaging, yet our DNA is damaged less than expected," Kohler said. "In the early evolution of life on Earth when there was no ozone layer, the amount of UV would have been far higher and yet life, and the DNA that is central to life, survived. We've been trying to understand the molecular mechanisms that make DNA resist UV damage."

In a paper published July 28 in the online version of the scientific journal, "Proceedings of the National Academy of Sciences" (PNAS), Kohler and his colleagues from MSU, Utah and Italy describe how DNA has a super-fast way of shrugging off the UV threat.

Too quick for the eye to see, UV light causes an electron to be transferred from one base to another on a single DNA strand. A base is the smallest unit of the genetic code, a small molecule that constitutes an individual "rung" on DNA's ladder.

In a next-generation solar cell, light also transfers electrons, but in DNA, the researchers observe that the transferred electron returns to its starting point in a fraction of a nanosecond. The back-and-forth motion of the electron explains how DNA remains undamaged most of the time. At the same time, the researchers note that the transferred electron could be used to repair damage in a way that mimics how certain repair proteins fix UV damage.

The finding is the latest in Kohler's 15-year search to understand what happens to DNA when it absorbs UV light.

The new discovery was possible because of a "lovely" infrared laser instrument built by Yuyuan (Tom) Zhang, an expert in ultrafast spectroscopy, a postdoctoral researcher at MSU and first author of the PNAS paper, Kohler said.

Zhang came to MSU about two years ago, and his first job was building the instrument that's the only one of its kind in Montana and one of only a handful in the world. The instrument shoots extremely short pulses of ultraviolet light at DNA samples, then measures the vibrations created in DNA in response. The vibrations are so fast that Kohler describes their speed in terms of femtoseconds instead of nanoseconds. A femtosecond is one millionth of a nanosecond. A nanosecond is one billionth of a second.

By analyzing those vibrations, the research team was able to determine that one base in a single strand of DNA transfers an electron to an adjacent base on the same strand when excited by UV light (or radiation), Kohler said. He added that molecules constantly vibrate, and light absorption leads to even greater vibrations. Removing or adding an electron causes changes to the pattern of vibrations, and that is what the MSU team measured in the lab.

The instrument they used takes up most of a room in MSU's Chemistry and Biochemistry Building. It incorporates black boxes, mirrors, stacked razor blades, tiny plastic tubes and what looks like a fish tank, with every component having a purpose and a place on the steel optical tables that hold them. The razor blades, for example, block laser beams. The mirrors direct light to the "fish tank," which holds DNA samples. The air inside the tank is drier than any desert so it won't contain the water vapor or carbon dioxide that could interfere with experiments.

Zhang said it took him three months to develop the instrument. Kohler said the instrument was critical for the DNA study, but yet it is available to MSU undergraduates and others who are trained to use it.


'/>"/>

Contact: Evelyn Boswell
evelynb@montana.edu
406-994-5135
Montana State University
Source:Eurekalert

Related biology news :

1. New paper amplifies hypothesis on human languages deep origins
2. Rising star uses paper to tackle food-borne diseases
3. Researchers receive top honors for ecology paper
4. Researchers design trees that make it easier to produce paper
5. Nano-paper filter removes viruses
6. Telecoupling paper honored as 2013s best
7. Analytical and Bioanalytical Chemistry Best Paper Award to Sherrie Elzey and De-Hao Tsai
8. Paper offers insights into network that plays crucial role in cell function and disease
9. Two papers unraveled the mystery of sex determination and benthic adaptation of the flatfish
10. The Protein Society announces the selection of 2 Protein Science Best Paper speakers
11. Paper predicts a future without carnivores would be truly scary
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/20/2016)...  VoiceIt is excited to announce its new ... By working together, VoiceIt and VoicePass will offer ... take slightly different approaches to voice biometrics, collaboration ... usability. Both ... "This marketing and technology partnership allows ...
(Date:5/9/2016)... , UAE, May 9, 2016 ... it comes to expanding freedom for high net worth ... Even in today,s globally connected world, there is still ... system could ever duplicate sealing your deal with a ... second passports by taking advantage of citizenship via investment ...
(Date:4/28/2016)... , April 28, 2016 First quarter ... (139.9), up 966% compared with the first quarter of 2015 ... totaled SEK 589.1 M (loss: 18.8) and the operating margin was ... (loss: 0.32) Cash flow from operations was SEK 249.9 ... 2016 revenue guidance is unchanged, SEK 7,000-8,500 M. The ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... 2016 , ... Charm Sciences, Inc. is pleased to announce ... Research Institute approval 061601. , “This is another AOAC-RI approval of the Peel ... President of Regulatory and Industrial Affairs. “The Peel Plate methods perform comparably to ...
(Date:6/23/2016)... ON (PRWEB) , ... June 23, 2016 , ... STACS ... DNA Technical Leader at the Arkansas State Crime Laboratory, has joined STACS DNA as ... the STACS DNA team,” said Jocelyn Tremblay, President and COO of STACS DNA. “In ...
(Date:6/23/2016)... On Wednesday, June 22, 2016, the NASDAQ Composite ... Jones Industrial Average edged 0.27% lower to finish at 17,780.83; ... has initiated coverage on the following equities: Infinity Pharmaceuticals Inc. ... NKTR ), Aralez Pharmaceuticals Inc. (NASDAQ: ARLZ ), ... more about these stocks by accessing their free trade alerts ...
(Date:6/23/2016)... , June 23, 2016 ... market research report to its pharmaceuticals section with ... product details and much more. Complete ... across 151 pages, profiling 15 companies and supported ... at http://www.reportsnreports.com/reports/601420-global-cell-culture-media-industry-2016-market-research-report.html . The ...
Breaking Biology Technology: