Effect of Ets1 knockdown in the P5424 thymic cell line

We performed ChIP-Seq for Ets1 and histone modifications in P5424 thymic cells, without and with Ets1 knockdown via shRNA. Overall, we find that loss of Ets1 results in specific, higher occupancy of H3K4me1-marked nucleosomes at the Ets1 binding site, but not H3K4me3 nucleosomes. We verified the specificity of this mechanism as Ets1-dependent by also computing H3K4me1 and 3 nucleosome occupancy in hypersensitive, Ets1-depleted sites. This effect was also found in primary WT DN+DP Ets1 sites. Overall, this suggests that Ets1 induces chromatin remodeling and that its loss increases H3K4me1 nucleosome occupancy in bound sites, with levels of H3K4me3 comparatively unchanged, thus reducing the activation status of these enhancers Overall design: Genome-wide analysis via ChIP-Seq for Ets1, H3K4me1 and H3K4me3 in WT, sh-scramble and sh-Ets1 the P5424 thymic cell line