The extent to which carbon flux is directed towards fermentation vs. respiration differs between cell types and environmental conditions. Understanding the basic cellular processes governing carbon flux is challenged by the complexity of the metabolic and regulatory networks. To reveal the genetic basis for natural diversity in channeling carbon flux, we applied Quantitative Trait Loci analysis by phenotyping and genotyping hundreds of individual F2 segregants of budding yeast that differ in their capacity to ferment the pentose sugar xylulose. Causal alleles were mapped to the RXT3 and PHO23 genes, two components of the large Rpd3 histone deacetylation complex. We show that these allelic variants modulate the expression of SNF1/AMPK-dependent respiratory genes. Our results suggest that over close evolutionary distances, diversification of carbon flow is driven by changes in global regulators, rather than adaptation of specific metabolic nodes. Such regulators may improve the ability to direct metabolic fluxes for biotechnological applications. Overall design: mRNA profiles of S. cerevisiae strain BY4741 with either the RXT3 or PHO23 genes either deleted, replaced by S. cerevisiae T73 allele or replaced by S. cerevisiae PHO23 allele
Natural Diversity in Pentose Fermentation Is Explained by Variations in Histone Deacetylases.
Cell line, Subject
View SamplesCells constantly adapt to changes in their environment. In the majority of cases, the environment shifts between conditions that were previously encountered during the course of evolution, thus enabling evolutionary-programmed responses. In rare cases, however, cells may encounter a new environment to which a novel response is required. To characterize the first steps in adaptation to a novel condition, we studied budding yeast growth on xylulose, a sugar that is very rarely found in the wild. We previously reported that growth on xylulose induces the expression of amino-acid biosynthesis genes, in multiple natural yeast isolates. This induction occurs despite the presence of amino acids in the growth medium and is a unique response to xylulose, not triggered by any of the naturally available carbon sources tested. Propagating these strains for ~300 generations on xylulose significantly improved their growth rate. Notably, the most significant change in gene expression was the loss of amino acid biosynthesis gene induction. Furthermore, the reduction in amino-acid biosynthesis gene expression on xylulose was strongly correlated with the improvement in growth rate, suggesting that internal depletion of amino-acids presented the major bottleneck limiting growth in xylulose. We discuss the possible implications of our results for explaining how cells maintain the balance between supply and demand of amino acids during growth in evolutionary 'familiar' vs. 'novel' conditions. Overall design: mRNA profiles of 12 wt S. cerevisiae strains grown on either YPD or YP-xylulose, before and after 300 generations evolution on YP-xylulose
Rapid evolutionary adaptation to growth on an 'unfamiliar' carbon source.
Cell line, Subject
View SamplesDepletion of essential nutrients triggers regulatory programs that prolong cell growth and survival. Starvation-induced processes increase nutrient transport, mobilize nutrient storage, and recycle nutrients between cellular components. This leads to an effective increase in intracellular nutrients, which may act as a negative feedback that down-regulates the starvation program. To examine how cells overcome this potential instability, we followed the transcription response of budding yeast transferred to medium lacking phosphate. Genes were induced in two temporal waves. The first wave was stably maintained and persisted even upon phosphate replenishment, indicating a positive feedback loop. This commitment was abolished after two hours with the induction of the second expression wave, coinciding with the reduction in cell growth rate. We identify genes that mediate this loss of commitment, and show that the overall temporal stability of the expression response depends on the sequential pattern of gene induction. Our results emphasize the key role of gene expression dynamics in optimizing cellular adaptation. Wild type cells were grown at high Phosphate medium, washed and transferred to no phosphate medium. Sample were taken every 15 minuets for 6 hours Overall design: 25 samples were taken during the time course. Expression data was normalized to the first time point (cells grown at high phosphate medium)
Sequential feedback induction stabilizes the phosphate starvation response in budding yeast.
Subject
View SamplesDepletion of essential nutrients triggers regulatory programs that prolong cell growth and survival. Starvation-induced processes increase nutrient transport, mobilize nutrient storage, and recycle nutrients between cellular components. This leads to an effective increase in intracellular nutrients, which may act as a negative feedback that down-regulates the starvation program. To examine how cells overcome this potential instability, we followed the transcription response of budding yeast transferred to medium lacking phosphate. Genes were induced in two temporal waves. The first wave was stably maintained and persisted even upon phosphate replenishment, indicating a positive feedback loop. This commitment was abolished after two hours with the induction of the second expression wave, coinciding with the reduction in cell growth rate. We identify genes that mediate this loss of commitment, and show that the overall temporal stability of the expression response depends on the sequential pattern of gene induction. Our results emphasize the key role of gene expression dynamics in optimizing cellular adaptation. ?phm3 cells were grown at high Phosphate medium, washed and transferred to no phosphate medium. Sample were taken every 15 minuets for 6 hours Overall design: 25 samples were taken during the time course. Expression data was normalized to the first time point (cells grown at high phosphate medium)
Sequential feedback induction stabilizes the phosphate starvation response in budding yeast.
Subject
View SamplesDepletion of essential nutrients triggers regulatory programs that prolong cell growth and survival. Starvation-induced processes increase nutrient transport, mobilize nutrient storage, and recycle nutrients between cellular components. This leads to an effective increase in intracellular nutrients, which may act as a negative feedback that down-regulates the starvation program. To examine how cells overcome this potential instability, we followed the transcription response of budding yeast transferred to medium lacking phosphate. Genes were induced in two temporal waves. The first wave was stably maintained and persisted even upon phosphate replenishment, indicating a positive feedback loop. This commitment was abolished after two hours with the induction of the second expression wave, coinciding with the reduction in cell growth rate. We identify genes that mediate this loss of commitment, and show that the overall temporal stability of the expression response depends on the sequential pattern of gene induction. Our results emphasize the key role of gene expression dynamics in optimizing cellular adaptation. pho90_OX cells were grown at high Phosphate medium, washed and transferred to no phosphate medium. Sample were taken every 15 minuets for 6 hours Overall design: 25 samples were taken during the time course. Expression data was normalized to the first time point (cells grown at high phosphate medium)
Sequential feedback induction stabilizes the phosphate starvation response in budding yeast.
Subject
View SamplesDepletion of essential nutrients triggers regulatory programs that prolong cell growth and survival. Starvation-induced processes increase nutrient transport, mobilize nutrient storage, and recycle nutrients between cellular components. This leads to an effective increase in intracellular nutrients, which may act as a negative feedback that down-regulates the starvation program. To examine how cells overcome this potential instability, we followed the transcription response of budding yeast transferred to medium lacking phosphate. Genes were induced in two temporal waves. The first wave was stably maintained and persisted even upon phosphate replenishment, indicating a positive feedback loop. This commitment was abolished after two hours with the induction of the second expression wave, coinciding with the reduction in cell growth rate. We identify genes that mediate this loss of commitment, and show that the overall temporal stability of the expression response depends on the sequential pattern of gene induction. Our results emphasize the key role of gene expression dynamics in optimizing cellular adaptation. phm3 damp cells were grown at high Phosphate medium, washed and transferred to no phosphate medium. Sample were taken every 15 minuets for 6 hours Overall design: 25 samples were taken during the time course. Expression data was normalized to the first time point (cells grown at high phosphate medium)
Sequential feedback induction stabilizes the phosphate starvation response in budding yeast.
Subject
View SamplesDepletion of essential nutrients triggers regulatory programs that prolong cell growth and survival. Starvation-induced processes increase nutrient transport, mobilize nutrient storage, and recycle nutrients between cellular components. This leads to an effective increase in intracellular nutrients, which may act as a negative feedback that down-regulates the starvation program. To examine how cells overcome this potential instability, we followed the transcription response of budding yeast transferred to medium lacking phosphate. Genes were induced in two temporal waves. The first wave was stably maintained and persisted even upon phosphate replenishment, indicating a positive feedback loop. This commitment was abolished after two hours with the induction of the second expression wave, coinciding with the reduction in cell growth rate. We identify genes that mediate this loss of commitment, and show that the overall temporal stability of the expression response depends on the sequential pattern of gene induction. Our results emphasize the key role of gene expression dynamics in optimizing cellular adaptation. ?vip1 cells were grown at high Phosphate medium, washed and transferred to no phosphate medium. Sample were taken every 15 minuets for 6 hours Overall design: 25 samples were taken during the time course. Expression data was normalized to the first time point (cells grown at high phosphate medium)
Sequential feedback induction stabilizes the phosphate starvation response in budding yeast.
Subject
View SamplesDepletion of essential nutrients triggers regulatory programs that prolong cell growth and survival. Starvation-induced processes increase nutrient transport, mobilize nutrient storage, and recycle nutrients between cellular components. This leads to an effective increase in intracellular nutrients, which may act as a negative feedback that down-regulates the starvation program. To examine how cells overcome this potential instability, we followed the transcription response of budding yeast transferred to medium lacking phosphate. Genes were induced in two temporal waves. The first wave was stably maintained and persisted even upon phosphate replenishment, indicating a positive feedback loop. This commitment was abolished after two hours with the induction of the second expression wave, coinciding with the reduction in cell growth rate. We identify genes that mediate this loss of commitment, and show that the overall temporal stability of the expression response depends on the sequential pattern of gene induction. Our results emphasize the key role of gene expression dynamics in optimizing cellular adaptation. pho85 damp cells were grown at high Phosphate medium, washed and transferred to no phosphate medium. Sample were taken every 15 minuets for 6 hours Overall design: 25 samples were taken during the time course. Expression data was normalized to the first time point (cells grown at high phosphate medium)
Sequential feedback induction stabilizes the phosphate starvation response in budding yeast.
Subject
View SamplesDepletion of essential nutrients triggers regulatory programs that prolong cell growth and survival. Starvation-induced processes increase nutrient transport, mobilize nutrient storage, and recycle nutrients between cellular components. This leads to an effective increase in intracellular nutrients, which may act as a negative feedback that down-regulates the starvation program. To examine how cells overcome this potential instability, we followed the transcription response of budding yeast transferred to medium lacking phosphate. Genes were induced in two temporal waves. The first wave was stably maintained and persisted even upon phosphate replenishment, indicating a positive feedback loop. This commitment was abolished after two hours with the induction of the second expression wave, coinciding with the reduction in cell growth rate. We identify genes that mediate this loss of commitment, and show that the overall temporal stability of the expression response depends on the sequential pattern of gene induction. Our results emphasize the key role of gene expression dynamics in optimizing cellular adaptation. ?phm4 cells were grown at high Phosphate medium, washed and transferred to no phosphate medium. Sample were taken every 15 minuets for 3.75 hours Overall design: 16 samples were taken during the time course. Expression data was normalized to the first time point (cells grown at high phosphate medium)
Sequential feedback induction stabilizes the phosphate starvation response in budding yeast.
Subject
View SamplesPrevalence and severity of allergic diseases have increased worldwide. To date, respiratory allergy phenotypes are not fully characterized and, in addition, the mechanisms underlying sublingual immunotherapy (SLIT) are still unknown.
Exploring novel systemic biomarker approaches in grass-pollen sublingual immunotherapy using omics.
Specimen part, Treatment, Time
View Samples