Retinoic Acid promotes a totipotent-like stem cell through Zscan4 epigenetic activation

In culture, embryonic stem cells (ESCs) are a heterogeneous population that includes several cell intermediates with different degrees of potency. In particular, the subpopulation marked by Zscan4 expression, resembling molecular and epigenetic two-cell stage preimplantation signature, results enhanced after RA-treatment. We detected the epigenetic mechanisms involved in Zscan4 activation RA-dependent. We identified the minimal Zscan4 promoter region responsive to epigenetic stimuli, such as AZA and TSA, using transgenic ESCs stably transfected with different deletions of the Zscan4 promoter regions and their specific mutation. Thus, we identified a minimal promoter region responsive to epigenetics stimuli, demonstrating that Zscan4 activation is related to the histone acetylation status and DNA demethylation. This Zscan4 promoter region, at -300 bp to TSS, contains binding motifs for the DUX and TBX transcription factors and three specific CpG sites responsible for Zscan4 RA-activation. The next step will be identifying the proteins that bind and regulate the Zscan4 activation RA-induced by using a dCAS9 system, followed by a Mass Spec analysis.