A new layer of transcriptional control N ⁶ -methyladenosine (m ⁶ A) is the most abundant messenger RNA modification in almost all eukaryotes. Liu et al. now show that m ⁶ A is also cotranscriptionally added onto various chromosome-associated regulatory RNAs (carRNAs) in mammalian cells. Disruption of m ⁶ A modification of these RNAs increases their abundance and promotes gene transcription by increasing the chromatin accessibility. Thus, m ⁶ A serves as a switch to regulate carRNA levels by tuning nearby chromatin state and downstream transcription. Science , this issue p. 580