Brona McVittie reports :: March 2007

Epigenetic marks on our DNA don’t just help cells to keep tabs on their past. Research carried out at the University of Birmingham in Alabama (USA) suggests that DNA and histone tags play a part in storing memories within the brain. DNMT, an enzyme that methylates DNA and silences genes, was found to be surprisingly active in rat hippocampus. Malfunctioning of this enzyme causes cognitive disorders like Rett syndrome and schizophrenia.

The researchers wondered whether it played some role in memory formation. They exposed rats to an electric shock. Within an hour DNMT activity had increased compared to rats that weren’t shocked. When the team blocked the enzyme function, the rats failed to recognise the shock-inducing stimulus. The scientists conclude that DNA methylation shuts down memory suppressor genes, helping rats to recall fearful stimuli, behaviour which might save their lives in the wild.

Research published in Neuron