Its characteristic rose-like aroma makes phenylethanol a popular ingredient in foods, beverages and cosmetics. Microbial production of phenylethanol currently relies on whole-cell bioconversion of phenylalanine with yeasts that harbor an Ehrlich pathway for phenylalanine catabolism. Complete biosynthesis of phenylethanol from a cheap carbon source such as glucose provides an economically attractive alternative for phenylalanine bioconversion. In this study, a Synthetic Genetic Array screening was applied to identify genes involved in regulation of phenylethanol synthesis in Saccharomyces cerevisiae. The screen focused on transcriptional regulation of ARO10, which encodes the major decarboxylase involved in conversion of phenylpyruvate to phenylethanol. A deletion in ARO8, which encodes an aromatic amino acid transaminase, was found to cause a transcriptional upregulation of ARO10 during growth with ammonium sulfate as the sole nitrogen source. Physiological characterization revealed that the aro8 mutation led to substantial changes in the absolute and relative intracellular concentrations of amino acids. Moreover, deletion of ARO8 led to de novo production of phenylethanol during growth on a glucose synthetic medium with ammonium as the sole nitrogen source. The aro8 mutation also stimulated phenylethanol production when combined with other, previously documented mutations that deregulate aromatic amino acid biosynthesis in S. cerevisiae. The resulting engineered S. cerevisiae strain produced over 3 mM of phenylethanol from glucose during growth on a simple synthetic medium. The strong impact of a transaminase deletion on intracellular amino acid concentrations opens new possibilities for yeast-based production of amino acid-derived products.
Deletion of the Saccharomyces cerevisiae ARO8 gene, encoding an aromatic amino acid transaminase, enhances phenylethanol production from glucose.
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View SamplesAddition of 3 new arrays made from carbon limited chemostat of CENPK113-7D and 3 new arrays made from aerobic carbon limited chemostat of CENPK113-7D Complmentary data to the data of the serie GSE1723.
Exploiting combinatorial cultivation conditions to infer transcriptional regulation.
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View SamplesRaw expression values (CHP data) for transcriptional profiling of the response of Saccharomyces cerevisiae to challenges with various weak organic acids
Generic and specific transcriptional responses to different weak organic acids in anaerobic chemostat cultures of Saccharomyces cerevisiae.
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View SamplesBackground
Combinatorial effects of environmental parameters on transcriptional regulation in Saccharomyces cerevisiae: a quantitative analysis of a compendium of chemostat-based transcriptome data.
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View SamplesZinc is indispensable for the catalytic activity and structural stability of many proteins, and its deficiency can have severe consequences for microbial growth in natural and industrial environments. For example, Zn depletion in wort negatively affects beer fermentation and quality. Several studies have investigated yeast adaptation to low Zn supply, but were all performed in batch cultures, where specific growth rate depends on Zn availability. The transcriptional responses to growth-rate and Zn availability are then intertwined, which obscures result interpretation. In the present study, transcriptional responses of Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under Zn limitation and excess in chemostat culture. To investigate the context-dependency of this transcriptional response, yeast was grown under several chemostat regimes resulting in various carbon (glucose), nitrogen (ammonium) and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified and enabled the definition of a Zn-specific Zap1 regulon comprising of 26 genes and characterized by a broader ZRE consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large amount of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified
Physiological and transcriptional responses of Saccharomyces cerevisiae to zinc limitation in chemostat cultures.
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View SamplesZinc is indispensable for the catalytic activity and structural stability of many proteins, and its deficiency can have severe consequences for microbial growth in natural and industrial environments. For example, Zn depletion in wort negatively affects beer fermentation and quality. Several studies have investigated yeast adaptation to low Zn supply, but were all performed in batch cultures, where specific growth rate depends on Zn availability. The transcriptional responses to growth-rate and Zn availability are then intertwined, which obscures result interpretation. In the present study, transcriptional responses of Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under Zn limitation and excess in chemostat culture. To investigate the context-dependency of this transcriptional response, yeast was grown under several chemostat regimes resulting in various carbon (glucose), nitrogen (ammonium) and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified and enabled the definition of a Zn-specific Zap1 regulon comprising of 26 genes and characterized by a broader ZRE consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large amount of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified.
Physiological and transcriptional responses of Saccharomyces cerevisiae to zinc limitation in chemostat cultures.
No sample metadata fields
View SamplesZinc is indispensable for the catalytic activity and structural stability of many proteins, and its deficiency can have severe consequences for microbial growth in natural and industrial environments. For example, Zn depletion in wort negatively affects beer fermentation and quality. Several studies have investigated yeast adaptation to low Zn supply, but were all performed in batch cultures, where specific growth rate depends on Zn availability. The transcriptional responses to growth-rate and Zn availability are then intertwined, which obscures result interpretation. In the present study, transcriptional responses of Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under Zn limitation and excess in chemostat culture. To investigate the context-dependency of this transcriptional response, yeast was grown under several chemostat regimes resulting in various carbon (glucose), nitrogen (ammonium) and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified and enabled the definition of a Zn-specific Zap1 regulon comprising of 26 genes and characterized by a broader ZRE consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large amount of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified
Physiological and transcriptional responses of Saccharomyces cerevisiae to zinc limitation in chemostat cultures.
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View SamplesMycosis fungoides (MF), the most common cutaneous T-cell lymphoma (CTCL), is a malignancy of mature, skin-homing T cells. Szary syndrome (Sz) is often considered to represent a leukemic phase of MF. In this study the pattern of numerical chromosomal alterations in MF tumor samples was defined using array-based CGH; simultaneously gene expression was analyzed using microarrays. Highly recurrent chromosomal alterations in MF include copy number gain of 7q36, 7q21-7q22 and loss of 5q13 and 9p21. This pattern characteristic of MF differs markedly from chromosomal alterations observed in Sz. Integration of data from array-based CGH and gene expression analysis yielded several candidate genes with potential relevance in the pathogenesis of MF. We confirmed that the FASTK and SKAP1 genes, residing in loci with recurrent gain, demonstrated increased expression. The RB1 and DLEU1 tumor suppressor genes showed diminished expression associated with loss. In addition, it was found that presence of chromosomal alterations on 9p21, 8q24 and 1q21-1q22 was associated with poor prognosis in patients with MF. This study provides novel insight into genetic alterations underlying MF. Furthermore, our analysis uncovered genomic differences between MF and Sz, which suggest that the molecular pathogenesis and therefore therapeutic requirements of these CTCLs may be distinct.
Oncogenomic analysis of mycosis fungoides reveals major differences with Sezary syndrome.
Specimen part
View SamplesStudy of the short term (within the first 330 seconds) transcriptional response of S.cerevisiae upon a sudden addition of glucose.
When transcriptome meets metabolome: fast cellular responses of yeast to sudden relief of glucose limitation.
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View SamplesOur analysis of the sfr6 freezing-sensitive mutant (Knight, H., Veale, E., Warren, G. J. and Knight, M. R. (1999). Plant Cell 11, 875-886.) and cls8 (unpublished) chilling-sensitive mutant of Arabidopsis, has revealed that the expression of certain cold-regulated genes is aberrant in both these mutants. In order to understand the molecular basis of chilling and freezing stress in Arabidopsis and also to determine commonalities and differences between these 2 different physiological stress-tolerance processes, we request transcriptome analysis for both of these mutants compared to wild type in one experiment, upon cold treatment and at ambient conditions. The sfr6 mutant shows the most severe phenotype with respect to cold gene expression, but is tolerant to chilling (Knight, H., Veale, E., Warren, G. J. and Knight, M. R. (1999). Plant Cell 11, 875-886.). However, it is unable to cold acclimate and hence is sensitive to freezing. The cls8 mutant, on the other hand, has a relatively mild phenotype relative to the cold-regulated genes we have examined, but is very sensitive to chilling temperatures (15 to 10 degree centigrade). It is thus likely that in cls8 we have not yet identified the genes which are most affected, and which account for the physiological phenotype. Both sfr6 and cls8 have been fine-mapped and are close to being cloned. The cls8 mutant has an altered calcium signature in response to cold which means it is likely to be affected in early signalling, e.g. cold perception itself.We will compare the expression profiles of genes in sfr6, cls8 and Columbia (parental line for both mutants), both at ambient, and after treatment with cold (5 degrees) for 3 hours. This timepoint is designed to capture both rapidly responding genes e.g. CBF/DREB1 transcription factors, and also more slow genes e.g. COR genes (KIN1/2 and LTI78). Pilot northerns confirm that this time point is suitable.This analysis will provide new insight into 2 novel genes required for tolerance to low temperature in Arabidopsis, and additionally will determine the nature of overlap between the separate processes of chilling and freezing tolerance.
The Arabidopsis mediator complex subunits MED16, MED14, and MED2 regulate mediator and RNA polymerase II recruitment to CBF-responsive cold-regulated genes.
Specimen part
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