TRANSCRIPTIONAL REGULATION OF THE YEAST VACUOLAR AMINOPEPTIDASE YSCI ENCODING GENE (APE1) BY CARBON-SOURCES

Transcription of the vacuolar aminopeptidase yscI-encoding gene (APE1) is regulated by the carbon source used for yeast growth, responding t o carbon catabolite repression. By Northern blot analyses, we determin ed the kinetics of glucose repression in growth-shift experiments. Whe n added to induced cells, glucose leads to the disappearance of hybrid izable aminopeptidase yscI RNA sequences within 30 min. However, the a mount of inmunoreactive protein, once induced, is not affected by the addition of glucose. By deletion analysis of the fusion gene APE1-lacZ we have identified a number of strong regulatory regions in the APE1 promoter. Consensus sequences for the binding of yAP1 and the HAP2/HAP 3/HAP4 complex are contained in those regions. Control of the APE1 gen e expression is not mediated by the HXK2 regulatory gene, but a strain bearing a deletion in the CAT1 gene can not derepress APE1 transcript ion to wild-type levels.