Transcriptomic profile of yeast cells lacking the high affinity K+-transport system. Saccharomyces cerevisiae

Potassium is the major intracellular cation in S. cerevisiae, which can be concentrated up to 200-300 mM even from relatively low potassium (< 1 mM) environments. This is achieved by mean of a high affinity K+-transport system encoded by the genes TRK1 and TRK2. Recently, our group became interested in the effects of sudden shortage of extracellular potassium. Transcriptomic analysis indicates that lack of potassium drastically alters sulfur metabolism (mainly Met and Cys metabolism), triggers an oxidative stress response and activates the mitochondrial retrograde pathway. We also observe a dramatic halt in the expression of genes required for ribosome biogenesis and translation, as well as decrease in expression of diverse genes (cyclins, protein kinases) required for progression through the cell cycle. Only subsets of these changes were observed in a strain deleted for the TRK1 and TRK2 genes growing in the presence of sufficient potassium (50 mM). Research involving molecular genetics and metabolomic approaches aiming to clarify the primary targets for potassium requirements is currently ongoing. Overall design: We compare the expression profile of two yeast strains: WT and trk1 trk2 double mutant, growing in a Translucent K-free medium containing 50 mM KCl until OD600 = 0.6. Two independent experiments were performed, and for each experiment a dye-swap was carried out. Total number of chips analyzed: 4.