Day 0: The TRs Rcan1, Taf1c, Tead4 and Tfap4 are expressed in naïve MEFS. Approximately 50% of naïve cells express all 4 factors. 18 hours: OSKM induce the expression of Cbfa2t3 in ~40% of the cells. Only a fraction of the population expresses all 5 TRs. Day 3: The expression of Gli2, Irf6, and Ovol1 has been induced by direct and indirect OSKM effects. Various interconnections between the TRs are established, thus stabilizing their expression. All eight TRs are expressed in a limited number of cells found exclusively in early-iPSCs colonies. Day 6: Nanog expression is induced in ~40% of the cells within the early-iPSCs colonies. All nine TRs are expressed only in ~6% of the cells found exclusively within these early formations. The nine TRs reconstruct the 9TR GRN, which is required to promote cellular reprogramming. iPSCs: The 9TR GRN GRN is dissolved in iPSCs because Ovol1 and Cbfa2t3 expression is dramatically reduced to undetectable levels. 