Figure 6

Model of how Kat2b epigenetically activates neuroectodermal genes upon differentiation. In hESCs, nucleosome positioning is overall fuzzy. Nucleosomes are densely packed in promoters that are at a repressive chromatin state with prevalent H3K27me3 marks. Upon differentiation, nucleosome positioning becomes phased. H3K27me3 signals are greatly reduced. Concomitantly, Kat2b deposits H3K9ac signals that enhance Sox2 binding. H2A.Z-mediated nucleosomes eviction creates an open chromatin structure for transcription machinery assembly. As a result, neuroectodermal genes are activated for neuroectodermal commitment