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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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DNA Damage Piles Up in the Aging Brain
9 June 2004 (All day)
Defective DNA has long been a suspect in the search for causes of impaired memory and learning. Now a comprehensive study of brain DNA provides solid evidence linking the culprit to the crime, which appears to be another woe of middle age.
A closer look at the crippled genes revealed damage caused by nasty free radicals, molecules that chew up DNA by the same process that turns metal to rust. Damage was most severe in the genes' promoter regions, the parts responsible for regulating when, and for how long, a gene is turned on. Compared to other sections of DNA, promoter regions are more vulnerable to attack from free radicals, and the cell can't repair them as well.
The results aren't all dismal though. The researchers also found that in older brains, activity was cranked up in genes that play a role in the body's immune response and combating stress and indicating that even if cells can't repair the damaged promoters, the brain tries to buffer the oxidative beating. And in human cells cultured in the lab, Yankner's team was able to repair much of the damage by artificially turning up the cell's DNA repair enzymes. While he cautions that the lab is a far cry from the brain, it raises the possibility that damage might be amenable to therapy in the future.
"The findings are really quite stunning," says neurologist Ann Graybiel of the Massachusetts Institute of Technology in Cambridge. "It gives new meaning to reaching 40."