In vitro activity assays confirmed that recombinant OsSET3 was a functional H3K9 methyltransferase while OsSET2 and OsSET4 were not.

• 利用大肠杆菌表达的OsSET2、OsSET3和OsSET4重组蛋白进行的体外活性检测实验证明OsSET3具有组蛋白H3K9的甲基转移酶活性，而OsSET2和OsSET4不具有该活性。