Nodal signaling maintains H3K18ac landscape to promote mesendodermal differentiation through TRIM33

The epigenome of a cell is established and maintained by chromatin modifiers and remodelers, which are recruited to the chromatin by specific transcription factors. In this report, we show that nodal cross-talks with the epigenome through TRIM33-H3K18ac to mediate mesendodermal genes expression. The chromatin accessibility at mesendodermal genes depends on TRIM33. Moreover, histone acetylation is essential for TRIM33 recruitment to many nodal target genes involved in mesendodermal differentiation. The distribution pattern of the H3K18ac mark changes from foci to expanded domains at the mesendodermal genes promoter during embryonic stem cells (ESCs) differentiation to embryoid bodies (EBs). This could be the cue to facilitate TRIM33 colocalized with Smad2/3 at chromatin in EBs but not in ESCs. TRIM33 interacts with the H3K18ac “writer” p300 dependent on nodal signaling, providing a positive feedback to promote activation of mesendodermal genes and association with HDAC1 plays a negative role in activation of mesendodermal genes.