N6-adenosine methylation in miRNAs

Methylation of N6-adenosine (me6A) has been observed in rRNA, tRNA, snoRNA, lncRNA and mRNA (ref.), but not yet miRNA. Interestingly, many mRNAs contain miRNA-binding sites and me6A in their 3''-UTR, although they do not appear to overlap (Mayer). We have investigated whether adenosine methylation affects miRNA levels and whether miRNAs are methylated. Indeed, we have obtained evidence suggesting that miRNA can be methylated and that the steady state level of certain miRNAs is affected by the level of the 6meA demethylase FTO. Overall design: RNA-Seq of small RNAs prepared from FTO knockdown cells. RNA-Seq of small RNA fraction first immunoprecipitated by antibody against me6A