UCLA and Kyoto University researchers mapped out the location of methyls on mRNA found at the synapses, or junctions, of mouse brain cells. They isolated brain cells from adult mice and compared the epitranscriptome found at the synapses to the epitranscriptomes of mRNA elsewhere in the cells. At more than 4,000 spots on the genome, the mRNA at the synapse was methylated more often. More than half of these spots, the researchers went on to show, are in genes that encode proteins found mostly at the synapse. The researchers found that when they disrupted the methylation of mRNA at the synapse, the brain cells didn’t function normally.
The methylation of mRNA at the synapse is likely one of many ways that neurons speed up their ability to send messages, by allowing the mRNA to be poised and ready to translate into proteins when needed.