New Nucleoside’s Hangouts Revealed

A mass spectrometry study has turned up a few surprises about which parts of the brain host a recently discovered piece of the DNA code. When researchers detected a new DNA nucleoside called 5-hydroxymethylcytosine last year, they suspected it might play a role in the brain, but its function remained unclear. Enter Thomas Carell, Martin Biel, and coworkers at Germany’s Ludwig Maximilians University. They made an ¹⁸O-labeled version of 5-hydroxymethylcytosine and used it as the cornerstone of an LC/MS method to determine how much of the compound is in various mouse brain tissues (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201002033). Scientists originally observed the nucleoside in the cerebellum, but the German team found far more of it in the cortex and hippocampus instead. They also found that the amount of 5-hydroxymethylcytosine in the mouse hippocampus goes up with age. The researchers didn’t identify a specific function for the molecule, but they note that both the cortex and hippocampus are associated with higher cognitive functions such as memory.