Micrococcal nuclease (MNase) is derived from Staphylococcus aureus, and its first use to determine chromatin structure dates back to 1975, when the method was called, variously, staphylococcal nuclease or micrococcal nuclease digestion of nuclei or chromatin.1, 2 With the advent of NGS, MNase digestion3 became more popular and the term MNase-Seq was coined finally4. The terms MNase-assisted isolation of nucleosomes sequencing (MAINE-seq)5, 6 Nucleo-Seq7, and Nuc-seq8 are not commonly used. MNase, fused to the protein of interest, has been also been used for calcium-dependent cleavage to study specific genomic loci in vivo (ChEC-seq)9.
In MNase-Seq, gDNA is treated with MNase. Sequences bound by chromatin proteins are protected from MNase digestion. Next, the DNA from the DNA-protein complexes is extracted and used to prepare a sequencing library. Deep sequencing provides accurate representation of the location of regulatory DNA-binding proteins in the genome10.