FIG. 2.

Structure of the ɛ-globin promoter and locations of positioned nucleosomes. Nucleosome positions in the region of the ɛ-globin promoter were previously determined by indirect end-labeling experiments (20). The dotted nucleosome is altered when the ɛ-globin gene is transcriptionally activated. An expanded view of the sequences underlying N1 illustrates regulatory sites within the promoter (shaded boxes), nuclease cleavage sites in actively transcribing promoters (large arrowheads), and restriction enzyme recognition sites (small arrowheads). Southern blot probes used in the experiments are indicated at the top by open bars over the corresponding sequences. The positions of amplified PCR products are indicated by filled bars.