Specific DNA binding of GAL4, a positive regulatory protein of yeast

We show by the following series of experiments that the yeast positive regulatory protein GAL4 binds to four sites in the upstream activating sequence UASG to activate transcription of the adjacent GAL1 and GAL10 genes. GAL4 protein expressed in E. coli protected guanine residues in UASG from methylation by dimethyl sulfate. The same set of protections was seen in vivo in yeast and depended on the GAL4+ allele. This protection pattern is...