a) NSD1 is a 2696 amino acid protein with ten conserved domains in addition to the SET and preceding SAC domains whilst EZH2 is a 746 amino acid protein with two SANT domains in addition to the SET and SAC. b) NSD1 is a histone methyltransferase which preferentially mono or di- methylates lysine residue 36 of histone 3 whereas EZH2 can catalyse the transfer of up to three methyl groups to lysine residue 27 of histone 3. NID, Nuclear interacting domain; PWWP, Proline, tryptophan, tryptophan, proline; PHD, plant homeodomain; SANT, Swi3, Ada2, N-cor TFIIIB.