Histone methylation plays crucial roles in epigenetic regulation.The SET domain proteins generally having methyltransferase activity targeted to specific lysine residues of histones.The enzymes and their specific histone lysine methylation have enormous impacts on the regulation of chromatin structure and function.Recently, we characterized a ubiquitin-associated tomato SET domian protein SUVH3 (SlSUVH3) that was implicated as the substrate of the Cul4-DDB1 E3 ligase.