Project description:We measured steady-state mRNA levels by microarray hybridization, comparing WT, (delta)ire1, (delta)gcn4, and (delta)gcn2 cells treated with 2 mM DTT for 30 min (by which time the UPR is qualitatively complete) to untreated samples of the same genotype. WT cells were taken as a positive control for UPR induction, and (delta)ire1 cells as a negative control. Fold change in expression of a given gene was computed as the ratio of mRNA level in the treated sample to the level in an untreated sample of the same genotype. Values reported here are the log2 fold change. Keywords = unfolded protein response Keywords = UPR Keywords = ire1 Keywords = gcn4 Keywords = gcn2
Project description:We measured steady-state mRNA levels by microarray hybridization, comparing WT, (delta)ire1, (delta)gcn4, and (delta)gcn2 cells treated with 2 mM DTT for 30 min (by which time the UPR is qualitatively complete) to untreated samples of the same genotype. WT cells were taken as a positive control for UPR induction, and (delta)ire1 cells as a negative control. Fold change in expression of a given gene was computed as the ratio of mRNA level in the treated sample to the level in an untreated sample of the same genotype. Values reported here are the log2 fold change. Keywords = unfolded protein response Keywords = UPR Keywords = ire1 Keywords = gcn4 Keywords = gcn2 Keywords: parallel sample
Project description:Ire1 is an endoplasmic reticulum (ER)-located transmembrane protein that triggers the unfolded protein response. I recently noticed that Ire1 is activated not only in response to ER accumulation of unfolded proteins but also alongside diauxic shift in yeast Saccharomyces cerevisiae cells. I thus asked how different the Ire1-target genes upon two distinct scenes, a canonical ER -stressing stimuli and diauxic shift. Thus NGS transcriptome analysis was performed by using IRE1+ and ire1-delta mutant yeast cells under these conditions.
Project description:The Snf1 kinase plays a critical role in recalibrating cellular metabolism in response to glucose depletion. Hundreds of genes show changes in expression levels when the SNF1 gene is deleted. However, cells can adapt to the absence of a specific gene when grown in long term culture. Here we apply a chemical genetic method to rapidly and selectively inactivate a modified Snf1 kinase using a pyrazolopyrimidine inhibitor. By allowing cells to adjust to a change in carbon source prior to inhibition of the Snf1 kinase activity, we identified a set of genes whose expression increased when Snf1 was inhibited. Prominent in this set are genes that are activated by Gcn4, a transcriptional activator of amino acid biosynthetic genes. Deletion of Snf1 increased Gcn4 protein levels without affecting its mRNA levels. The increased Gcn4 protein levels required the Gcn2 kinase and Gcn20, regulators of GCN4 translation. These data indicate that Snf1 functions upstream of Gcn20 to regulate control of GCN4 translation. Experiment Overall Design: Strains growing in raffinose medium and expressing Snf1 and Snf1-I132G proteins were treated with a pyrazolopyrimidine inhibitor (2NM-PP1) to specifically inhibit Snf1-I132G kinase activity. RNA combined from three individual transformants were processed in duplicate for each strain, for a total analysis of four Affymetrix Yeast Genome S98 arrays.
Project description:The yeast protein kinases Sat4/Hal4 and Hal5 are required for the plasma membrane stability of the K+ transporter Trk1 and some amino acid and glucose permeases. The transcriptomic analysis presented here indicates alterations in the general control of both nitrogen and carbon metabolism. Accordingly, we observed reduced uptake of methionine and leucine in the hal4 hal5 mutant. This decrease correlates with activation of the Gcn2-Gcn4 pathway, as measured by expression of the lacZ gene under the control of the Gcn4 promoter. However, with the exception of methionine biosynthetic genes, few amino acid biosynthetic genes are induced in the hal4 hal5 mutant, whereas several genes involved in amino acid catabolism are repressed. Concerning glucose metabolism, we found that this mutant exhibits derepression of respiratory genes in the presence of glucose, leading to an increased activity of mitochondrial enzymes, as measured by SDH activity. In addition, the reduced glucose consumption in the hal4 hal5 mutant correlates with a more acidic intracellular pH and with low activity of the plasma membrane H+-ATPase. As a compensatory mechanism for the low glycolytic rate, the hal4 hal5 mutant overexpresses the HXT4 high affinity glucose transporter and the hexokinase genes. These results indicate that the hal4 hal5 mutant presents defects in the general control of nitrogen and carbon metabolism, which correlate with reduced transport of amino acids and glucose, respectively. A more acidic intracellular pH may contribute to some defects of this mutant.