Genome-wide rotational and translational phasing of nucleosomes with human transcription factors

How transcription factors (TFs) and their binding sites organize and engage nucleosomes at natural genomic locations remains poorly understood. Here we develop Benzonase-seq to measure the rotational phasing of nucleosomes in human cells, and enhance ChIP-exo (v6) to measure rotational phasing on the same DNA molecule bound by a TF. Unbound CTCF sites were found to be rotationally accessible on nucleosomes and this rotational accessibility is encoded by classical dinucleotide periodicities. CTCF binding results in nucleosome displacement to adjacent DNA phasing sequences. Examining 40 TF classes, their unbound sites were phased inward, outward, or lacked phasing. In all examined cases, TF binding (e.g. NFIA and FoxA) results in adjacent rotational and translational phasing, which is not dinucleotide encoded. Benzonase-seq also more robustly maps nucleosome and subnucleosome positions in hard-to-map CpG islands. These findings provide a clearer view of how TFs engage and position nucleosomes to shape the natural chromatin landscape.