Four SWI2/SNF2 chromatin remodeling proteins play roles as “double agents” in the tug of war between RNA-directed DNA methylation and active DNA demethylation in Arabidopsis [small RNA]

Here we report that CLSY4 and its three paralogous SWI2/SNF2-type chromatin remodeling proteins function in both RdDM and active DNA demethylation for dynamic regulation of DNA methylation in Arabidopsis. We identified CLSY4 initially in a genetic screen for DNA demethylation factors and subsequently demonstrated that it also plays an important role in RdDM. Comprehensive genetic analyses using single and high order mutants of CLSY family proteins revealed their roles as double agents in the tug of war between methylation and demethylation reactions. The four CLSY proteins collectively are necessary for the canonical RdDM pathway; meanwhile, each CLSY also mediates active DNA demethylation at specific loci where DNA methylation is dependent on one or more of the other three CLSY proteins. Our results revealed dual functions of the four chromatin remodeling proteins in regulating genomic DNA methylation status, and thus provide new insights into the mechanisms underlying the dynamic regulation of DNA methylation in Arabidopsis. small RNA sequencing data of clsy1234 and WT