Fig. 3.

Enzyme titrations comparing the methyltransferase activities of insect cell-expressed and Escherichia coli-expressed MLL4-WRAD₂ complexes in the scintillation/filter plate assay. (A) The E. coli-expressed (□) and insect cell-expressed (♦) preparations assayed with HeLa mono/di-nucleosomes. (B) Insect cell-expressed complex assayed with HeLa oligonucleosomes (same data as [A], expanded scale). Linear regression line is y=162.6x+113.6, with R²=0.9717. (C) E. coli-expressed enzyme (□, ■) was assayed with recombinant histone H3.3 (□) or core histones (■), as was the insect cell-expressed preparation (◯, H3.3), (●, core histones). The linear fit to the insect/core histones data (●) is y=117.9x+783.0 with R²=0.9986.