Fig. 6. Kinetics of EKLF and GATA1 expression during EB differentiation. (A) EBs were differentiated for varying lengths of time (days, as indicated) in SR1 before addition of BMP4. All samples were harvested at day 8 and total RNA was analyzed for EKLF, GATA1 or HPRT expression. Expression in the presence of serum was included as a positive control, and ‘water’ indicates a no-RNA negative control. (B) The onset of EKLF expression was monitored in EBs differentiating in FBS or in SR1 and BMP4, as indicated for varying lengths of time (days). Asterisk indicates a no-RNA negative control.