FUNCTIONAL-ANALYSIS OF UPSTREAM ACTIVATING ELEMENTS IN THE PROMOTER OF THE FBP1 GENE FROM SACCHAROMYCES-CEREVISIAE

We have investigated the effect of different carbon sources and of dif ferent mutations on the capacity of two elements, UAS 1 and UAS2, from the promoter of the FBP1 gene to form specific DNA-protein complexes and to activate expression of a reporter gene. The complexes are obser ved with nuclear extracts from yeast derepressed on glycerol or ethano l. When hxk2 mutants are grown on glucose the nuclear extracts are abl e to complex UAS 1 but not UAS2, while for wild-type cells grown on ga lactose only the complex with UAS2 is formed. In contrast, in vivo the operation of both UASs is high in ethanol, moderate to low in glycero l, and negligible in galactose; no expression is observed in glucose e ven in a hxk2 background. There is no effect of a MIG1 deletion, eithe r in the formation of DNA-protein complexes or on the expression of re porter genes.