C2H2-zinc finger domains mediate targeting of REF6 on the genome of Arabidopsis. Arabidopsis thaliana

In Arabidopsis, H3K27me3 demethylase JMJ12 / RELATIVE OF EARLY FLOWERING 6 (REF6) has been shown to play important roles in transcriptional regulation and plant development via demethylation of H3K27me3 at hundreds of regions in the genome. However, the mechanism underlying REF6 targeting remains elusive. Here, we show that a tandem of C2H2-zinc finger (C2H2-ZF) domains on the C-terminal of JMJ12/REF6 are required for its biological function. The REF6 proteins without C2H2-ZF domains (REF6ΔZF) failed to rescue the ref6 mutant phenotypes and resulted in an abnormal subcellular localization of REF6 protein. Genome-wide analysis revealed that REF6ΔZF missed its targets in the genome and blocked the function of H3K27me3 demethylation on its target genes. Our findings indicate that C2H2-ZF domains are essential for REF6 biological function by mediating REF6 targeting, which provide a new clue to explore the targeting mechanism of JmjC-containing proteins in plant.