FIG. 2.

Stable expression of Dnmt3a and Dnmt3b isoforms in late-passage 7aabb cells. (A) Schematic diagram of Dnmt3a and Dnmt3b isoforms. The conserved PWWP and PHD domains, the methyltransferase motifs (I, IV, VI, IX, and X), and the sites of alternative splicing are indicated (the C-terminal 45 amino acids of Dnmt3b5 are out of frame and shown as an open bar). The locations of the epitopes for the Dnmt3a and Dnmt3b antibodies are also shown. (B) cDNAs encoding Dnmt3a/3b isoforms were subcloned in an expression vector (schematically shown at the top), and these constructs were individually electroporated into late-passage (P70) 7aabb cells, which were subsequently selected in blasticidin-containing medium for 7 days. Blasticidin-resistant clones were analyzed with immunoblotting with anti-Dnmt3a (middle panel) or anti-Dnmt3b (bottom panel) antibodies. As a loading control, the same membranes were immunoblotted with anti-tubulin antibody.