Genome-wide approaches to determining nucleosome occupancy in metazoans using MNase-Seq

The precise location of nucleosomes in functional regulatory regions in chromatin is critical to the regulation of transcription. The nucleosome structure protects DNA from microccocal nuclease (MNase) digestion and leaves a footprint on DNA that indicates the position of nucleosomes. Short sequence reads (25-36 bp) from ends of mononucleosome-sized DNA generated from MNase digestion of chromatin can be determined using next-generation sequencing techniques. Mapping of these short reads to the genome provides a powerful genome-wide approach to precisely define the nucleosome positions in any genome with known genomic sequence. This chapter outlines the reagents and experimental procedures of MNase-Seq for mapping nucleosome positions in the human genome.