ABSTRACT
More than 100 modifications have been found in RNA. Analogous to epigenetic DNA methylation, epitranscriptomic modifications can be written, read, and erased by a complex network of proteins. Apart from N-methyladenosine (mA), N-methyladenosine (mA) has been found as a reversible modification in tRNA and mRNA. mA occurs at positions 9, 14, and 58 of tRNA, with mA58 being critical for tRNA stability. Other than the hundreds of mA sites in mRNA and long non-coding RNA transcripts, transcriptome-wide mapping of mA also identifies >20 mA sites in mitochondrial genes. mA in the coding region of mitochondrial transcripts can inhibit the translation of the corresponding proteins. In this review, we summarize the current understanding of mA in mRNA and tRNA, covering high-throughput sequencing methods developed for mA methylome, mA-related enzymes (writers and erasers), as well as its functions in mRNA and tRNA.