Expression of GUT1, which encodes glycerol kinase in Saccharomyces cerevisiae, is controlled by the positive regulators Adr1p, Ino2p and Ino4p and the negative regulator Opi1p in a carbon source-dependent fashion

摘要

In Saccharomyces cerevisiae glycerol utilization is mediated by two enzymes, glycerol kinase (Gut1p) and mitochondrial glycerol-3-phosphate dehydrogenase (Gut2p). The carbon source regulation of GUT1 was studied using promoter-reporter gene fusions. The promoter activity was lowest during growth on glucose and highest on the non-fermentable carbon sources, glycerol, ethanol, lactate, acetate and oleic acid. Mutational analysis of the GUT1 promoter region showed that two upstream activation sequences, UAS_INOINO and UAS_INOADR1, are responsible for ～90% of the expression during growth on glycerol. UAS_INOADR1 is a presumed binding site for the zinc finger transcription factor Adr1p and UAS_INOINO is a presumed binding site for the basic helix-loop-helix transcription factors Ino2p and Ino4p. In vitro experiments showed Adr1 and Ino2/Ino4 protein-dependent binding to UAS_INOADR1 and UAS_INO. The negative regulator Opi1p mediates repression of the GUT1 promoter, whereas the effects of the glucose repressors Mig1p and Mig2p are minor. Together, the experiments show that GUT1 is carbon source regulated by different activation and repression systems.