Atg7-dependent autophagy regulates the naive to primed transition by selective Nanog degradation in mouse embryonic stem cells [ChIP-seq]
Autophagy is a conserved cellular mechanism to degrade unwanted cytoplasmic proteins and organelles to recycle their components, and it is proved to be critical for embryonic stem cell (ESC) self-renewal and somatic cell reprogramming. However, the role of autophagy in embryonic development remains elusive, and no information exists regarding its functions during the transition from naive to primed pluripotency. Here by using an in vitro transition model of ESCs to epiblast-like cells (EpiLCs), we describe that the dynamic changes in Atg7-dependent autophagy is required for the naive to primed transition, and it is also necessary for germline specification. RNA-seq and ATAC-seq profiling reveal that Nanog acts as a barrier to prevent pluripotency transition, and autophagy-dependent Nanog degradation is important for dismantling the naive pluripotency expression program through decommissioning of naive-associated active enhancers. Mechanistically, we found that autophagy adaptor protein Sqstm1 (p62) is nucleus located during the pluripotency transition period and it is preferentially associated with ubiquitinated Nanog for selective protein degradation. In vivo, loss of autophagy by Atg7 depletion disrupts peri-implantation development and we observed increased chromatin association of Nanog, which affects neuronal differentiation through activation of a subset of neuroectodermal development-associated enhancers. Taken together, our findings illuminate regulatory mechanisms underlying the naive to primed transition and reveal that autophagy-dependent regulation of Nanog is essential for exit from the naive state and marks distinct cell fate allocation during lineage specification. Overall design: The ChIP-Seq experiments of the Control and Atg7 KO groups were taken at each time point from the 4-day ESC to EpiLC transition.