H3K4me3 recruits the chromatin remodeling DILL-PICKLE-PEPPERCORN complexes to promoters in plants

The plant CHD chromatin remodeler PICKLE (PKL) is a master regulator of cellular identity and differentiation, controlling developmental, hormonal and stress-response processes. Yet the molecular mechanisms underlying its function remain unclear. Here, we show that PKL forms three complexes, each composed of a protein of previously unknown function and one of three mutually exclusive novel DNAJ proteins that recruit HSP70-1. Simultaneous loss of all three DNAJs phenocopies the pkl mutant, indicating functional redundancy among PKL complexes. In vitro activity assays and cryo-electron microscopy reveal that PKL clamps nucleosomal DNA via its ATPase motor domain and recognizes H3K4me3 through its double chromodomain. Genome-wide profiling shows that H3K4me3 recognition positions PKL complexes at genic promoters to bidirectionally fine-tune gene expression. Together, these results provide structure-function insight into PKL recruitment and its control of developmental gene expression, and reveal a chaperone-coupled complex assembly that offers a broader perspective on how chaperone networks may support chromatin remodeling complexes across eukaryotes.