The m⁶A-YTH regulatory system in plants: A status

Plants use mRNA methylation to regulate gene expression. As in other eukaryotes, the only abundant methylated nucleotide in plant mRNA bodies is N6-methyladenosine (m⁶A). The conserved core components of m⁶A-based genetic control are a multi-subunit nuclear methyltransferase, and a set of nuclear and cytoplasmic RNA-binding proteins consisting of an m⁶A recognition module, the YT521-B homology (YTH) domain, and long intrinsically disordered regions (IDRs). In plants, this system is essential for growth during embryonic and post-embryonic development, but emerging evidence also points to key functions in plant-virus interactions and stimulus-dependent gene regulation. Cytoplasmic YTH-domain proteins are particularly important for these functions, and recent progress has identified two elements of the underlying molecular mechanisms: IDR-mediated phase separation and conserved short linear motifs mediating interactions with other key mRNA-binding proteins.