FIGURE 1.

DNMT3A is processive on a variety of substrates, as shown using a pulse-chase assay. A, poly(dI-dC) (5 μm bp). B, EFS1 human promoter (10 μm bp). C, bacterial supercoiled plasmid pBR322 (10 μm bp). D and E, the p21 human promoter in the pCpG^L plasmid, linearized (20 μm bp) (D) and supercoiled (20 μm bp) (E). Substrate was added at time 0 to start the reaction. Full-length DNMT3A is at 50 nm, and AdoMet is at 2 μm. ■ = only substrate; ● = substrate and then 200 μm bp pCpG^L at 20 min; ▴ = substrate and 200 μm bp pCpG^L at the start of the reaction.