JMJ28 guides sequence-specific targeting of ATX1/2-containing COMPASS-like complex in Arabidopsis

Despite extensive investigations in mammals and yeasts, the importance and specificity of COMPASS-like complex, which catalyzes histone 3 lysine 4 methylation (H3K4me), are not fully understood in plants. Here, we report that JMJ28, a Jumonji C domain-containing protein in Arabidopsis, recognizes specific DNA motifs through a plant-specific WRC domain and acts as an interacting factor to guide the chromatin targeting of ATX1/2-containing COMPASS-like complex. JMJ28 associates with COMPASS-like complex in vivo via direct interaction with RBL. The DNA-binding activity of JMJ28 is essential for both the targeting specificity of ATX1/2-COMPASS and the deposition of H3K4me at specific loci but exhibit functional redun-dancy with alternative COMPASS-like complexes at other loci. Finally, we demonstrate that JMJ28 is a nega-tive regulator of plant immunity. In summary, our findings reveal a plant-specific recruitment mechanism of COMPASS-like complex. These findings help to gain deeper insights into the regulatory mechanism of COMPASS-like complex in plants.

Automated summary

In this study, researchers report that JMJ28 protein in Arabidopsis plays a crucial role in the recruitment and targeting of ATX1/2-containing COMPASS-like complex by recognizing specific DNA motifs through a plant-specific WRC domain. They also found that JMJ28 associates with COMPASS-like complex via direct interaction with RBL and its DNA-binding activity is essential for the targeting specificity and deposition of H3K4me at specific loci. Additionally, JMJ28 is identified as a negative regulator of plant immunity.