Extended Data Figure 1: In vitro DNA methyltransferase activity of DNMT3A.

a, In vitro DNA methyltransferase activities of DNMT3A2 (purified from insect cells) in the absence or presence of C^DNMT3L. The assays were performed in the presence or absence of histone H3 peptide (residues 1–12). Note that C^DNMT3L could enhance the activity of DNMT3A2 by a factor of 2–3, which is consistent with previous study²². However, histone H3-mediated activation of DNMT3A is independent of the existence of C^DNMT3L. b, In vitro DNA methyltransferase activities of DNMT3A2 (purified from insect cells) or DNMT3A2–C^DNMT3L (purified from bacteria) in the presence or absence of histone H3 peptides. c, Enzymatic activities of DNMT3A2 (purified from insect cells) or DNMT3A2–C^DNMT3L (purified from bacteria) using reconstituted nucleosomes as substrates. Nucleosomes containing unmodified histone H3 or H3K_C4me3 were subject to SDS–PAGE and visualized using specific antibodies. d, e, Enzymatic activities of various N-terminal deletions of DNMT3A2 in the absence (d) or presence (e) of C^DNMT3L. Corresponding relative activities are indicated at the bottom of each figure. CPM, counts per minute. Error bars, s.d. for triplicate experiments. The ADD–CD or CD protein purified from bacteria was not stable in solution and tended to precipitate out, which may have resulted in their lower activities under our experimental conditions (compared with DNMT3A2 purified from insect cells). Because C^DNMT3L could stabilize DNMT3A and had no effect on histone H3-mediated activation, protein complexes ADD–CD–C^DNMT3L and CD–C^DNMT3L were used in the following studies if not specified.