Emerging roles of RNA modification: m(6)A and U-tail.

Although more than 100 types of RNA modification have been described thus far, most of them were thought to be rare in mRNAs and in regulatory noncoding RNAs. Recent developments have unveiled that at least some of the modifications are considerably abundant and widely conserved. This Minireview summarizes the molecular machineries and biological functions of methylation (N6-methyladenosine, m(6)A) and uridylation (U-tail).