Mouse Embryonic Stem Cells Resist c-Jun induced Differentiation in Suspension

The oncogene c-Jun plays a key role in development and cancer. Yet, its role in cell fate decision remains poorly understood at the molecular level. Here we report that c-Jun confers different fate decisions upon mouse embryonic stem cells (mESCs) in adhesion vs suspension. We developed a Tet-on system for temporal induction of c-Jun expression by Doxycycline treatment in mESCs. We show that mESCs carrying the inducible c-Jun TetOn remain pluripotent and grow slowly in suspension with induction of c-Jun, while undergoing differentiation with normal proliferative potentials in adherence upon c-Jun induction. Apparently, c-Jun pushes mESCs in suspension into cell cycle arrest at G1/S, through the induction of Cdkn1a/b and Cdkn2/a/b/c. Despite cell cycle arrest, they can re-enter cell cycle upon plating on adhesive surface and grow into typical mESC colonies albeit at lower efficiency. These results demonstrate that mESCs respond to c-Jun differently in suspension or adherence. Our results suggest that cells in suspension may be more resistant to differentiation than in adherence. TRE-ESCs cells were cultured in N2B27+2i+LIF medium in low adsorption petri dish with or without dox