We also examined nucleosome occupancy relative to the symmetry properties of chromatin marks around TF-binding sites. Around TSSs, there is usually strong asymmetric nucleosome occupancy, often accounting for the majority of the histone modification signal (for instance, see Supplementary Figure E4). However, away from TSSs, there is far less concordance. For example, CTCF-binding sites typically show arrays of well-positioned nucleosomes on either side of the peak summit (Supplementary Figure E1)63. Where the flanking chromatin mark signal is high, the signals are often asymmetric, indicating differential marking with histone modifications (Supplementary Figure E2 and E3). Thus, we confirm on a genome-wide scale that TFs can form barriers around which nucleosomes and histone modifications are arranged in a variety of configurations63–66. Further detail is explored in refs25,26,30.
