Figure 4
Steady state analysis when OCT4-SOX2 over-expression is varied. Time series concentrations of NANOG (red), OCT4-SOX2 (blue) and G (green) obtained from stochastic simulation when reprogramming occurs. Reprogramming efficiency when over-expression of OCT4-SOX2 is varied. (A) The steady state values of NANOG, OCT4-SOX2 and G as functions of over-expression (α) of OCT4-SOX2 for LIF=100 and I3=10 respectively. The gene regulatory circuitry is initially in the somatic state with G high and NANOG and OCT4-SOX2 low. The reprogramming occurs when G turns OFF while NANOG and OCT4-SOX2 turn ON (at α≃0.001). At higher values of α(α≃0.2), there now exist two states of the system: the existing ES state and the differentiated state which occurs since G turns ON while OCT4-SOX2 and NANOG switch to lower levels. (B) Time series of NANOG, OCT4-SOX2 and G for one case when the reprogramming was successful, G turns OFF while NANOG and OCT4-SOX2 turn ON for LIF=100 and I3 = 0.05 respectively. (C) The reprogramming efficiency for values of α varying from 0 to 0.4 and I3 taking 0 and 0.4 values, LIF=100