RNA methylation is emerging as a regulatory RNA modification that could have important roles in the control and coordination of gene transcription and protein translation. Herein, we describe an in vivo isotope-tracing methodology to demonstrate that the ribonucleoside 5-methylcytidine (m(5)C) is subject to oxidative processing in mammals, forming 5-hydroxymethylcytidine (hm(5)C) and 5-formylcy...
