In vivo regulation of glucose transporter genes at glucose concentrations between 0 and 500 mg/L in a wild type of Saccharomyces cerevisiae

When the yeast Saccharomyces cerevisiae consumes glucose, the expression of the genes for the glucose transport is controlled via signal transduction pathways and sensor molecules. Most publications describe the behavior of deletion strains while little is published about the in vivo regulation of glucose transporters in a wild type of S. cerevisiae.Here a global gene expression analysis via microarray experiments from cultivations with glucose concentrations of 50, 70, 100 and 500 mg/L is presented. This permits the observation of the fine-tuning of gene expression in dependency on the glucose concentration. We detected indications that the transport system for high glucose concentrations is activated at glucose concentrations between 50 and 100 mg/L. The regulation of genes coding enzymes for the signal pathways and of those encoding the transporters themselves supports this assumption.The expression of sensor-, signal- and transporter genes will be discussed in detail. In addition, new information about the behavior of the so far little described carriers HXT8, HXT12, HXT13, HXT17 and GAL2 will be given. According to our findings, HXT13 is active during starvation. HXT12, HXT17 and GAL2 are used at low glucose concentrations. The carrier HXT8 supports the glucose transport both during starvation and at low glucose concentrations.