Peter McKinnon, PhD

Broken DNA is bad for the brain

DNA may be the cornerstone of life, but the molecule breaks all the time. To read DNA’s code or make more DNA, cells routinely nick and unwind the famous double helix using specialized enzymes. Free radicals and other stresses can also break DNA.

Usually, cells just repair the break and life goes on. But if repair processes fail, the damaged DNA can hurt cells and tissues. DNA damage has been linked to diseases such as cancer and neurodegenerative disorders.

Research from St. Jude Children’s Research Hospital has revealed an unexpected cause for the DNA damage in two rare childhood diseases of the brain. In models of these diseases, an enzyme used by cells to nick DNA becomes trapped in the molecule. Because of disease-associated defects in the normal repair process, the enzyme stays trapped, leading to permanent DNA damage.

“We are now working to understand how this newly recognized source of DNA damage might contribute to tumor development or age-related DNA damage in the brain that is associated with neurodegenerative disorders like Alzheimer’s disease,” said Peter McKinnon, PhD, of the Department of Genetics.

The findings appear in the journal Nature Neuroscience.

May 9, 2014

Read the news release