RNA N6-methyladenosine methylation in post-transcriptional gene expression regulation

N 6 -methyladenosine (m 6 A) is the most prevalent and internal modification that occurs in the messenger RNAs (mRNA) of most eukaryotes, although its functional relevance remained a mystery for decades. This modification is installed by the m 6 A methylation “writers” and can be reversed by demethylases that serve as “erasers.” In this review, we mainly summarize recent progress in the study of the m 6 A mRNA methylation machineries across eukaryotes and discuss their newly uncovered biological functions. The broad roles of m 6 A in regulating cell fates and embryonic development highlight the existence of another layer of epigenetic regulation at the RNA level, where mRNA is subjected to chemical modifications that affect protein expression.