ChIP-chip analysis of histone acetylation across 220-kb of chromosome 16p13.3. (A) Overview of the human α globin locus. The positions of erythroid-specific DNase1 hypersensitive sites (eDHSs) associated with the murine MCS elements are shown at the top. The genes located in the telomeric region of chromosome 16p are shown. The red shadow box represents the putative α globin regulatory domain exchanged between human and mouse to produce the humanized mouse model.10 The region of conserved synteny is represented as a horizontal bar. Below this, all CpG islands, DHSs, eDHS, and multispecies conserved regulatory sequences (MCS-R1-4) are shown. The human eDHS corresponding to MCS-R are labeled. (B) H4ac and H3ac in cells collected on day 8 of the second phase of culture (Day 8 Ery) and in T lymphocytes (T Ly) are shown. The y-axis represents enrichment of ChIP DNA over input DNA from 1 experiment. A very similar pattern of enrichment was seen for each biologic replicate. (All replicates are available at the website http://www.imm.ox.ac.uk/groups/mrc_molhaem/home_pages/Higgs.) The x-axis represents the α globin locus. Gray columns run from CpG islands through the array data. CpG islands not represented on the array are marked with an asterisk. V marks CpG islands which are not associated with promoters. Dashed vertical lines run from mouse eDHS through the array data.
