FIG. 3.

Multiple DNase I-hypersensitive sites at the H4/n locus. Nuclei were digested with increasing concentrations of DNase I. DNA was purified and cleaved with PstI/BamHI (A) or HpaI (B). After Southern blotting the filter was hybridized with the XbaI-PstI fragment (A) or the HpaI PCR probe fragment (+336/+500) (B) (see Fig. 2A). The diagram at the left indicates the positions of transcription regulatory elements and the transcription start site. The + sign designates the area of altered nuclease sensitivity. Other symbols and abbreviations are described in the legend to Fig. 2.