FoxO transcription factors actuate the formative pluripotency specific gene expression programme [ATAC-Seq]

Naïve pluripotency is sustained by a self-reinforcing gene regulatory network (GRN) comprising core and naïve pluripotency-specific transcription factors (TFs). Upon exiting naïve pluripotency, ES cells transition through a formative post-implantation-like pluripotent state. However, the mechanisms underlying disengagement from the naïve GRN and initiation of the formative GRN remain unclear. Here, we demonstrate that phosphorylated AKT acts as a gatekeeper that prevents nuclear localization of FoxO TFs in naïve ESCs. PTEN-mediated reduction of AKT activity allows nuclear entry by FoxO TFs, enforcing a cell fate transition by binding and activating formative pluripotency-specific enhancers. Indeed, FoxO TFs are necessary and sufficient for transition from the naïve to the formative pluripotent state. Our work uncovers a pivotal role for FoxO TFs and AKT signalling in mechanisms underlying the exit from naïve pluripotency, a critical early embryonic cell fate transition. Overall design: ATAC-seq of WT and Pten KO mESC, in pluripotency supporting conditions (2i) and 24hours after 2i withdrawal (N24).