Scientists Discover How Environmental Contaminants Can Damage DNA, Cause Diseases

Publishing in Nature, National Institute of Health scientists say they have discovered a specific way in which polluted environments are damaging human DNA and potentially leading to a variety of human diseases including cancer, diabetes, Alzheimer’s, and cardiovascular ailments that are known to in turn be strong risk factors for psychiatric conditions.

Using a new imaging technique of time-lapse crystallography, the researchers “found that the biological machinery that builds DNA can insert molecules into the DNA strand that are damaged as a result of environmental exposures,” stated a press release about the study.

In the press release, co-author Samuel Wilson explained that “the damage is caused by oxidative stress, or the generation of free oxygen molecules, in response to environmental factors, such as ultraviolet exposure, diet, and chemical compounds in paints, plastics, and other consumer products.”

“When one of these oxidized nucleotides is placed into the DNA strand, it can’t pair with the opposing nucleotide as usual, which leaves a gap in the DNA,” Wilson said. “Until this paper, no one had actually seen how the polymerase did it or understood the downstream implications.”

“The damaged nucleotide site is akin to a missing plank in a train track,” Wilson said. “When the engine hits it, the train jumps the track, and all of the box cars collide.”

(Full text) Uncovering the polymerase-induced cytotoxicity of an oxidized nucleotide (Freudenthal, Bret D. et al. Nature. Published online November 17, 2014. doi:10.1038/nature13886)

NIH scientists determine how environment contributes to several human diseases (National Institutes of Health Press Release, November 25, 2014)