DNA Double-Strand Breaks Are Key to Normal Learning & Memory, But Then Cause Brain Degeneration As DNA Repair Slows Down with Aging; Such Breaks Found Critical for Normal Expression of Neuronal “Early-Response” Genes

The same process that allows our brains to learn and generate new memories also leads to degeneration as we age, according to a new study by researchers at MIT. The finding, published online on June 4, 2015 in the journal Cell, could ultimately help researchers develop new approaches to preventing cognitive decline in disorders such as Alzheimer's disease. The Cell article is titled “Activity-Induced DNA Breaks Govern the Expression of Neuronal Early-Response Genes.” Each time we learn something new, our brain cells break their DNA, creating damage that the neurons must immediately repair, according to Dr. Li-Huei Tsai, the Picower Professor of Neuroscience and Director of the Picower Institute for Learning and Memory at MIT. This process is essential to learning and memory. "Cells physiologically break their DNA to allow certain important genes to be expressed," Dr. Tsai says. "In the case of neurons, they need to break their DNA to enable the expression of early-response genes, which ultimately pave the way for the transcriptional program that supports learning and memory, and many other behaviors." However, as we age, our cells' ability to repair this DNA damage weakens, leading to degeneration, Dr. Tsai says. "When we are young, our brains create DNA breaks as we learn new things, but our cells are absolutely on top of this and can quickly repair the damage to maintain the functionality of the system," Dr. Tsai says.
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