Fig 3.

Induced HIS3 plasmid chromatin is more accessible to restriction enzymes at sites both near and far from the HIS3 promoter. Time courses of digestion of uninduced and induced sucrose gradient-purified TA-HIS3 chromatin with exogenous plasmid DNA as internal control, analyzed by indirect end-labeling. (A) Accessibility of the MscI site in HIS3: the phosphorimage of a Southern blot probed with a fragment of the HIS3 gene is shown. (*, Spurious band derived from plasmid control.) (B) Quantification of the data in A: uninduced (Unind) (•) and induced (Ind) (▪) TA-HIS3 chromatin; control plasmid DNA mixed with uninduced (○) or induced (□) chromatin. (C–E) Time courses of digestion by XbaI, HincII, and PleI, respectively. Symbols are as in B. See Fig. 1A for the locations of restriction sites.