Yeast Gal Promoter
Induction of the Gal genes in yeast.
The constitutively expressed proteins GAL80 and GAL4 regulate expression of several genes required for the conversion of galactose to glucose-6-phosphate. The product of the GAL4 gene binds to the Upstream Activating Sequence (UAS-GAL). The activating effect of GAL4 is repressed by GAL80. In the presence of galactose, a metabolic product is formed which releases GAL80p from GAL4p and then activation of the GAL genes cluster occurs.