Exon Junction Complex Is a Molecular Compass of N6-Methyladenosine Modification

Abstract

N6-methyladenosine (m6A) is the most prevalent internal mRNA modification in mammals and plays crucial roles in pre-mRNA splicing, mRNA translation, and mRNA stability. Recent studies from three separate research groups have brought to light the regulation of m6A installation by exon junction complexes (EJCs), which are deposited immediately upstream of each exon-exon junction following splicing. These studies have revealed that the EJCs deposited onto mRNAs act as a barrier, limiting the accessibility of METTL3/14 complex (known as m6A writer complex), thereby preventing m6A modification in regions of mRNA proximal to the exon-exon junctions. The discovery of this EJC-mediated reshaping of m6A transcriptome paves the way for new research opportunities to comprehend a wide array of molecular, cellular, and physiological events associated with the EJC and m6A. © The Korean Society for Molecular and Cellular Biology.