Scale map of DHS in U-937 cells (vertical arrows) relative to the AZU1, PRTN3, ELA2, and ADN genes and to restriction fragments used for DHS mapping (short vertical lines), (A, Hpa I; B, BamHI; C, Sca I; G, Bgl II; L, Bcl I; M, Mlul; R, EcoRI; X, Xbal, and Y, BssHII). Horizontal arrows depict orientation of end-labeled detection of DHS. Exons from the 4 genes used as probes for DHS analysis are shown (half-boxes) for each restriction fragment used for DHS mapping. The EcoRI fragment encompassing AZU1 extends 24 kb beyond the AZU1 gene and the EcoRI fragment at the ADN end of the locus is 31 kb. Multiple analyses using different restriction fragments were used to confirm the location of the DHS in U-937 and in other cell lines.