FIG. 2.

Dnmt[3a^−/−,3b^−/−] ES cells lose differentiation capacities with prolonged passage and progressive demethylation. Photomicrographs of normal erythroid (day 10) (A) and myeloid (day 20) (B) differentiation of wild-type ES cell colonies. Examples of absent (C) and atypical (diffuse low-level) (D) erythroid differentiation are also shown. Bar charts depicting the extent of DNA methylation (meth.) (E), percentage of colonies showing erythroid differentiation (diff.) (F), myeloid differentiation (G), and EBs showing cardiomyocyte differentiation (H) are shown for wild-type, Dnmt1^−/−, and Dnmt[3a^−/−,3b^−/−] ES cells of different passages. The x axis labels shown in panel H are the same for all graphs. The error bars indicate standard deviations. Asterisks indicate a low level of diffuse hemoglobinization.