The complexity of PRC2 catalysts CLF and SWN in plants

Polycomb repressive complex 2 (PRC2) is an evolutionally conserved multisubunit complex essential for the development of eukaryotes. In Arabidopsis thaliana (Arabidopsis), CURLY LEAF (CLF) and SWINGER (SWN) are PRC2 catalytic subunits that repress gene expression through trimethylating histone H3 at lysine 27 (H3K27me3). CLF and SWN function to safeguard the appropriate expression of key developmental regulators throughout the plant life cycle. Recent researches have advanced our knowledge of the biological roles and the regulation of the activity of CLF and SWN. In this review, we summarize these recent findings and highlight the redundant and differential roles of CLF and SWN in plant development. Further, we discuss the molecular mechanisms underlying CLF and SWN recruitment to specific genomic loci, as well as their interplays with Trithorax-group (TrxG) proteins in plants.