Restriction endonuclease accessibility as a determinant of altered chromatin structure.

Active genes in eukaryotic genomes are typically found in open, nuclease-sensitive regions of chromatin. This chapter presents an overview of the techniques used to assay restriction endonuclease cleavage of chromosomal DNA as an approach to assess general accessibility at a genomic region of interest. We describe protocols to (1) prepare nuclei templates, (2) treat chromosomal DNA with a restriction enzyme(s), and (3) visualize and quantify chromosomal cleavage(s), with an emphasis on ligation-mediated (LM) PCR techniques.