Dissection of PRC1 and PRC2 recruitment in Arabidopsis connects EAR repressome to PRC2 anchoring

Abstract

PcG complexes ensure that every cell in an organism expresses the genes needed at a particular stage, time or condition. However, it is still not fully understood how PRC1 and PRC2 are recruited to target genes in plants. Recent results in Arabidopsis support that PRC2 recruitment is mediated by different TFs. However, it is unclear how all these TFs interact with PRC2 and whether they can also recruit PRC1 activity. Here, by using a system to in vivo bind selected factors to a synthetic promoter lacking the complexity of PcG target promoters, we show that while VAL1 binding recapitulates PRC1 and PRC2 marking, the binding of other TFs only render PRC2 marking. Interestingly, all these TFs contain an EAR domain that acts as docking point for PRC2 and HDACs, connecting two different repressive mechanisms. Furthermore, we show that different TFs act synergistically in PRC2 anchoring to maintain a long-term repression.