Transition from pluripotency to differentiation is a pivotal yet poorly understood developmental step. Here, we show that the tumour suppressor RASSF1A is a key player driving the early specification of cell fate. RASSF1A acts as a natural barrier to stem cell self-renewal and iPS cell generation, by switching YAP from an integral component in the β-catenin-TCF pluripotency network to a key factor that promotes differentiation. We demonstrate that epigenetic regulation of the Rassf1A promoter maintains stemness by allowing a quaternary association of YAP-TEAD and β-catenin-TCF3 complexes on the Oct4 distal enhancer. However, during differentiation, promoter demethylation allows GATA1-mediated RASSF1A expression which prevents YAP from contributing to the TEAD/β-catenin-TCF3 complex. Simultaneously, we find that RASSF1A promotes a YAP-p73 transcriptional programme that enables differentiation. Together, our findings demonstrate that RASSF1A mediates transcription factor selection of YAP in stem cells, thereby acting as a functional "switch" between pluripotency and initiation of differentiation.
Adaptor Proteins, Signal Transducing, Animals, Basic Helix-Loop-Helix Transcription Factors, Cell Differentiation, DNA-Binding Proteins, Embryonic Stem Cells, Female, Gene Expression Regulation, Developmental, Humans, Male, Mice, Inbred C57BL, Mice, Inbred CBA, Octamer Transcription Factor-3, Phosphoproteins, Protein-Serine-Threonine Kinases, Signal Transduction, Transcription Factors, Tumor Protein p73, Tumor Suppressor Proteins, Wnt Proteins, beta Catenin