Changes in chromatin accessibility at the MMTV array locus and at endogenous sites in response to pulsed and constant hormone stimulation. (A) High-resolution mapping of the GR binding profile at the MMTV locus demonstrates an excellent concordance between the results obtained by single cell imaging (Fig. 1B) and the GR ChIP-seq method. (B) DNase I digestion reveals the presence of a transient DNase I hypersensitive site (DHS) at the MMTV locus coinciding with the major GR peak (black arrows). Hypersensitivity of this site is contingent upon GR binding, suggesting a direct involvement of the receptor in the DHS establishment and maintenance. (C) Examples of endogenous transient DHSs. (D) Examples of endogenous persistent DHSs.
