Scientists get a glimpse of chemical tagging in live brains

PET scan

LEAVING A MARK A new radioactive tracer molecule shows where chemical tags, called epigenetic marks, are made in the brains of healthy people. Shown is the epigenetic activity in a volunteer’s brain imaged 60 to 90 minutes after injection of the tracer. 

H.-Y. Wey et al./Science Translational Medicine 2016

For the first time scientists can see where molecular tags known as epigenetic marks are altered in the brain.

These chemical tags — which flag DNA or its protein associates, known as histones — don’t change the genes, but can change gene activity. Abnormal epigenetic marks have been associated with brain disorders such as Alzheimer’s disease, schizophrenia, depression and addiction.

Researchers at Massachusetts General Hospital in Boston devised a tracer molecule that latches onto a protein that removes one type of epigenetic mark, known as histone acetylation.

The scientists then used PET scans to detect where a radioactive version of the tracer appeared in the brains of eight healthy young adult men and women, the researchers report August 10 in Science Translational Medicine. Further studies could show that the marks change as people grow older or develop a disease. The team studied only healthy young volunteers so can’t yet say whether epigenetic marking changes with age or disease.

Editor’s note: This story was updated August 17, 2016, to correct the type of epigenetic process being visualized. 

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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