Figure 5.—

Silencing elements in the genomic context of a silencer regulate its potency and directionality. (A) HML-E affects the apparent directionality of HML-I. Left, strains used. Right, growth phenotypes of these strains on SC, 5-FOA, and −Ura media. [Δ] denotes the deletion of a sequence. (B) HMR-I affects the apparent directionality of HMR-E. Left, strains used. Right, growth phenotypes. (C) Effect of UASα on the directionality of HMR-E in the context of HML-I. The Rap1p-binding site (designated R1) in UASα (upstream activating sequence of the α1 and α2 genes) is indicated by a bar in strains 210–213. Note that R1 is highlighted only in certain relevant strains in this report. UASα was deleted in strains 214 and 215. Growth phenotypes of strains 210–215 are shown on the right.