ZIC2 and ZIC3 promote SWI/SNF recruitment to safeguard progression towards human primed pluripotency [ChIP-seq]

The primed epiblast acts as a transitional stage between the relatively homogeneous naïve epiblast and the gastrulating embryo. Its formation entails coordinated changes in regulatory circuits driven by strict epigenetic mechanisms. Using a multi-omic approach in human embryonic stem cell models across the spectrum of peri-implantation development, we demonstrate that the transcription factors ZIC2 and ZIC3 have overlapping but essential roles in opening primed-specific enhancers. Together they are essential to facilitate progression to and maintain primed pluripotency. ZIC2/3 achieve their function by recruiting SWI/SNF to chromatin and loss of ZIC2/3 or degradation of SWI/SNF both prevent enhancer activation. Loss of ZIC2/3 results in transcriptome changes consistent with perturbed Polycomb activity and a shift towards the expression of genes linked to mesendoderm differentiation. Additionally, we find an intriguing dependency on the transcriptional machinery for sustained recruitment of ZIC2/3 over a subset of primed-hESC specific enhancers. Taken together, ZIC2 and ZIC3 regulate highly dynamic lineage-specific enhancers and collectively act as key regulators of human primed pluripotency.