5-hydroxymethylcytosine-mediated epigenetic dynamics during neurodevelopment and aging [mRNA profiling]

DNA methylation dynamics influence brain function and are altered in neurological disorders. 5-hydroxymethylcytosine (5-hmC), a DNA base derived from 5-methylcytosine (5mC) accounts for ~40% of modified cytosine in brain, and has been implicated in DNA methylation-related plasticity. Here we map 5-hmC genome-wide across three ages in mouse hippocampus and cerebellum, allowing assessment of its stability and dynamic regulation during postnatal neurodevelopment through adulthood. We find developmentally programmed acquisition of 5-hmC in neuronal cells. Epigenomic localization of 5-hmC-regulated regions reveals stable and dynamically modified loci during neurodevelopment and aging. By profiling 5-hmC in human cerebellum we establish conserved genomic features of 5-hmC. Finally, we implicate 5-hmC in neurodevelopmental disease by finding that its levels are inversely correlated with methyl-CpG-binding protein 2 (Mecp2) dosage, a protein encoded by a gene in which mutations cause Rett Syndrome. These data point toward critical roles for 5-hmC-mediated epigenetic modification in neurodevelopment and diseases.