Effects of GAL10-SUC2 promoter combinations on SUC2 gene expression in S. cerevisiae.

The plasmid series YEP51 delta n bearing GAL10-SUC2 promoter combinations were constructed by inserting SUC2 gene with different upstream deletions downstream GAL10 promoter on YEP51. After transforming yeast cells S. cerevisiae, the invertases expressed by each of the transformants were measured and analysed by means of PAGE. The results showed that: 1) The SUC2 gene with upstream deletion to at -636bp expressed high level glycosylated form of invertase under glucose derepression, while SUC2 gene with more extensive deletions to -223 bp or more lost its response to glucose derepression; 2) Each part of GAL10-SUC2 promoter combination acted almost independently. All of the combinations showed no apparent coordinated promoter function under our experimental conditions; 3) Sequences between -89bp and -41bp of SUC2 upstream region are responsible for constitutive expression of nonglycosylated invertase. The two tracts of poly (dA-dT) of this region may serve as promoter elements.