FIG. 7.

Dnmt1 and Dnmt3 proteins function cooperatively in maintaining methylation patterns. (A) Dnmt1 or Dnmt3a was overexpressed in 7aabb (P70) or Dnmt1^−/− (c/c) ES cells as indicated and stable clones were examined for protein expression by immunoblotting with anti-Dnmt1 (top), anti-Dnmt3a (middle), and anti-tubulin (bottom) antibodies. (B and C) Genomic DNA from the indicated ES cell lines was analyzed for methylation of repetitive sequences (B) and unique genes (C) with the indicated probes.