EKLF induction negatively affects megakaryocyte formation during embryoid body (EB) differentiation. (A) Doxycycline treatment of a stable embryonic stem (ES) cell line that contains single-copy, integrated tetO-EKLF-GFP results in robust expression of GFP and EKLF within 24 hours. GFP was monitored by FACS, EKLF was monitored by anti-FLAG Western blot analysis of extracts. Representative results are shown. (B) EKLF was induced in differentiating EBs by treatment with doxycycline at day 4 and harvested at day 8. Representative FACS analyses are shown for hematopoietic progenitor (c-Kit), progenitor/megakaryocyte (CD41), and megakaryocyte (CD42b) markers. All gates were drawn based on negative controls for each sample (not shown). The table (percentages) is a subset of a more extensive analysis summarized as Table S2.