Accessibilità del genoma

This is a high-throughput sequencing based method to map euchromatin and heterochromatin accessibility. The method is based on the sequential extraction of distinct nuclear fractions containing: soluble proteins (S1 fraction); the surnatant obtained after DNase treatment (S2 fraction); DNase-resistant chromatin extracted with high salt buffer (S3 fraction); and the most condensed and insoluble portion of chromatin, extracted with urea buffer that solubilizes the remaining proteins and membranes (S4 fraction).