Fig. 5.

Histone lysine methyltransferases(HKMTs): classfication, histone targets, primary domain architecture. HKMTs are classified in two types: the SET domain-containing proteins and the DOT1-like proteins. The SET domain-containing proteins can be subdivided into four families by structural sequence features: SUV39, SET1, SET2 and RIZ. Except for these family listed above, there are other SET domain -containing methyltransferases that have not been classfied into a specific group, for instance, SET8, SET7/9, SMYD subfamily and SUV4–20 subfamily