Structure of METTL3-METTL14 with an m6A nucleotide reveals insights into m6A conversion and sensing.

The nuclear METTL3-METTL14 transfers a methyl group from SAM to convert the of adenosine (A) in RNA to mA and in ssDNA to 6mA. mA marks are prevalent in eukaryotic mRNAs and lncRNAs and modulate their stability and fate in a context-dependent manner. The cytoplasmic METTL3 can act as a mA reader.