EOMES safeguards TSC chromatin accessibility by directing BRG1 to TSC-associated loci [CUT&RUN]

EOMES is an essential transcription factor (TF) for murine trophoblast stem cell (TSC) maintenance. Despite that, the details of EOMES' function at the molecular level remain obscure. Here, we carried out rapid immunoprecipitation and mass spectrometry of endogenous protein (RIME) to identify TSC-specific protein interactors on EOMES. In addition to other established TFs involved in TSC maintenance, we found that EOMES interacts with several chromatin remodeller subunits, including BRG1. By exploiting an Eomes-degron system, we acutely depleted EOMES protein in TSCs and in parallel inhibited BRG1 function with small molecule BRM014. EOMES depletion and BRG1 inhibition resulted in reduced accessibility at largely overlapping genomic regions associated with TSC-related loci. Additionally, EOMES depletion results in misregulation of genes essential for TSC maintenance and function, as well as genes encoding cytoskeletal, cell-cell interaction and matricellular components. Investigation of EOMES chromatin occupancy by Cleavage UnderTargets and Release Using Nuclease (CUT&RUN) with a rabbit polyclonal anti-Eomes antibody and an anti-rabbit IgG control antibody.