Female mouse embryonic stem cells (mESCs) contain two active X chromosomes, with one undergoing random inactivation upon differentiation. Schulz et al. (2014) now demonstrate that the presence of two active X chromosomes in mESCs prevents exit from pluripotency by blocking MAPK signaling, ensuring synchronization between X chromosome dosage compensation and development.
Copyright © 2014 Elsevier Inc. All rights reserved.