Abstract 2215 The histone chaperone FACT maintains murine embryonic stem cell pluripotency by regulating. The genomic landscape

The FACT complex is a conserved and essential histone chaperone with roles in replication, transcription, and repair. FACT is thought to reassemble nucleosomes in vivo to promote chromatin integrity after the passage of RNA Pol II during transcription. While FACT is dispensable for most non- cancerous mammalian cell types, depletion of FACT in stem cells results in loss of pluripotency, yet, the precise mechanism through which FACT regulates cell fate decisions remains unclear. We found that AID-mediated depletion of FACT in murine embryonic stem cells (mESCs) led to increased nucleosome occupancy at loci bound by master pluripotency factors while simultaneously downregulating both mRNA and enhancer transcripts associated with Pou5f1 (OCT4), Sox2, Nanog and their targets.