FIG. 4.

Nuclease mapping of ORF50 promoter chromatin. (A) Partial Mnase digestion of JSC1 cells treated with (+) or without (−) NaB was assayed by Southern blotting and probed with ORF50 sequences (positions 71301 to 71598). Hypersensitive sites are indicated by the arrows, and molecular size standards are indicated to the right. (B) Endonuclease sensitivity assay of ORF50 promoter region in JSC1 cells treated with (+) or without (−) NaB. Nuclei were incubated with Asp718 (left panel) or HincII (right panel), and then isolated DNA was cleaved with NcoI/EcoRV and analyzed by Southern blotting with an ORF50-specific probe. Asp718 (left panel) and HincII (right panel) cleavage products are indicated. A schematic of ORF50 restriction sites, GC box, and presumptive nucleosomes is indicated below. (C) Schematic indicating restriction sites and probe used for indirect end-labeling.