DNA sequence influences hexasome orientation to regulate DNA accessibility.

Nucleosomes, the fundamental organizing units of eukaryotic genomes, contain ∼146 base pairs of DNA wrapped around a histone H3-H4 tetramer and two histone H2A-H2B dimers. Converting nucleosomes into hexasomes by removal of a H2A-H2B dimer is an important regulatory event, but its regulation and functional consequences are not well-understood. To investigate the influence of hexasomes on DNA accessibility, we used the property of the Widom-601 Nucleosome Positioning Sequence (NPS) to form homogeneously oriented hexasomes in vitro.