Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA369411 | ENA |
REPOSITORIES: ENA
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Project description:Phosphatidylcholine (PC) is an abundant membrane lipid component in most eukaryotes including yeast. PC has been assigned a multitude of functions in addition to that of building block of the lipid bilayer. Here we show that PC is evolvable essential in yeast by isolating suppressor mutants devoid of PC that exhibit robust growth. The requirement for PC is suppressed by monosomy of chromosome XV, or by a point mutation in the ACC1 gene encoding acetyl-CoA carboxylase. Although these two genetic adaptations rewire lipid biosynthesis differently, both decrease Acc1 activity thereby reducing the average acyl chain length. Accordingly, soraphen A, a specific inhibitor of Acc1, rescues a yeast mutant with deficient PC synthesis. In the aneuploid suppressor, up-regulation of lipid synthesis is instrumental to accomplish feed-back inhibition of Acc1 by acyl-CoA produced by the fatty acid synthase (FAS). The results show that yeast regulates acyl chain length by fine-tuning the activities of Acc1 and FAS, and indicate that PC evolved by benefitting the maintenance of membrane fluidity.
2021-08-04 | GSE75725 | GEO
Project description:The aim of this work is to investigate whether A. thaliana senses low temperature by perceiving changes in membrane fluidity. To this end, we have performed an experiment to test whether mutant or transgenic plants with altered membrane lipid composition, regulate their gene expression in the same manner as wild type plants in response to cold. Previous work has demonstrated that a change in the expression levels of a number of genes is important in acquiring tolerance to low temperatures. Chemicals which rigidify cell membranes in such a way as to mimic the effects of cold have been shown to be able to induce the expression of such genes. However, because of the non-specific nature of such chemical treatments, it has not been possible to demonstrate unequivocally that the changes in gene expression observed were the result of changes in membrane fluidity. All of the mutants used in our experiment, fab1, fad2-2 and the fad3/fad7/fad8 mutant, have increased lipid saturation levels compared to wild type plants and are thought to have reduced membrane fluidity. The fab1 mutant is also known to be sensitive to chilling. In the fab1 mutant the elongation of 16:0 fatty acids to 18:0 is reduced. The fad2-2 mutant has reduced 18:1 desaturase activity and hence reduced amounts of polyunsaturated phospholipids. The fad3/fad7/fad8 triple mutant is deficient in 18:2 desaturase activity and consequently unable to synthesise trienoic fatty acids. The transgenic line used contained a 35S::FAD3 transgene and in contrast to the mutants tested, should have increased lipid desaturation and increased membrane fluidity. A. thaliana ecotype Col-0 was used as the wild type control for the fab1 and fad2-2 mutants, in addition to the 35S::FAD3 line. The fad3/fad7/fad8 mutant had previously been transformed with the 35S::apoaequorin transgene and a Columbia line expressing apoaequorin under the control of the same promoter, was included to control for the presence of aequorin. Nine day old seedlings grown in petri-dishes on MS were transferred from their growth room (20 oC, 16 h photoperiod, 100 E m-2 s-1) to a growth cabinet (20 oC, 16 h photoperiod,160 m-2 s-1) 24 hours before the experiment began. The next day, one petri-dish of seedlings from each line of plants used was transferred to a cabinet running at 5 oC (16 h photoperiod,160 E m-2 s-1). Control plates remained at 20 oC. Seedlings were harvested after three hours and frozen in liquid nitrogen.
2008-02-15 | E-NASC-66 | biostudies-arrayexpress
Project description:The aim of this work is to investigate whether A. thaliana senses low temperature by perceiving changes in membrane fluidity. To this end, we have performed an experiment to test whether mutant or transgenic plants with altered membrane lipid composition, regulate their gene expression in the same manner as wild type plants in response to cold. Previous work has demonstrated that a change in the expression levels of a number of genes is important in acquiring tolerance to low temperatures. Chemicals which rigidify cell membranes in such a way as to mimic the effects of cold have been shown to be able to induce the expression of such genes. However, because of the non-specific nature of such chemical treatments, it has not been possible to demonstrate unequivocally that the changes in gene expression observed were the result of changes in membrane fluidity. All of the mutants used in our experiment, fab1, fad2-2 and the fad3/fad7/fad8 mutant, have increased lipid saturation levels compared to wild type plants and are thought to have reduced membrane fluidity. The fab1 mutant is also known to be sensitive to chilling. In the fab1 mutant the elongation of 16:0 fatty acids to 18:0 is reduced. The fad2-2 mutant has reduced 18:1 desaturase activity and hence reduced amounts of polyunsaturated phospholipids. The fad3/fad7/fad8 triple mutant is deficient in 18:2 desaturase activity and consequently unable to synthesise trienoic fatty acids. The transgenic line used contained a 35S::FAD3 transgene and in contrast to the mutants tested, should have increased lipid desaturation and increased membrane fluidity. A. thaliana ecotype Col-0 was used as the wild type control for the fab1 and fad2-2 mutants, in addition to the 35S::FAD3 line. The fad3/fad7/fad8 mutant had previously been transformed with the 35S::apoaequorin transgene and a Columbia line expressing apoaequorin under the control of the same promoter, was included to control for the presence of aequorin. Nine day old seedlings grown in petri-dishes on MS were transferred from their growth room (20 oC, 16 h photoperiod, 100 E m-2 s-1) to a growth cabinet (20 oC, 16 h photoperiod,160 m-2 s-1) 24 hours before the experiment began. The next day, one petri-dish of seedlings from each line of plants used was transferred to a cabinet running at 5 oC (16 h photoperiod,160 E m-2 s-1). Control plates remained at 20 oC. Seedlings were harvested after three hours and frozen in liquid nitrogen. 12 samples were used in this experiment
2013-08-30 | E-GEOD-50435 | biostudies-arrayexpress
Project description:CRISPR interference screening of 129 protein kinases and 161 transcription factors in S. cerevisiae. Repression effects on yeast growth in oxygen-limited conditions were quantified in synthetic complete media (SCM), SCM supplemented with 10% lignocellulose hydrolysate and SCM supplemented with 45% of a mixture of growth-inhibiting lignocellulosic compounds. The aim of this project was to determine the reproducibility of CRISPRi effects across studies and to characterize CRISPRi for screening of phenotypes relevant for industrial biotechnology. We identify gene functions in general growth in oxygen-limited conditions, and specific for cellular fitness in lignocellulose hydrolysate. A further screen with a cocktail of lignocellulosic compounds enables us to explain hydrolysate-specific gene functions with roles in toxicity.
2021-02-15 | GSE155590 | GEO
Project description:Kavšček2015 - Genome-scale
metabolic model of Yarrowia lipolytica (iMK735)
This model is described in the article:
Optimization of lipid
production with a genome-scale model of Yarrowia
lipolytica.
Kavšček M, Bhutada G, Madl
T, Natter K.
BMC Syst Biol 2015; 9: 72
Abstract:
Yarrowia lipolytica is a non-conventional yeast that is
extensively investigated for its ability to excrete citrate or
to accumulate large amounts of storage lipids, which is of
great significance for single cell oil production. Both traits
are thus of interest for basic research as well as for
biotechnological applications but they typically occur
simultaneously thus lowering the respective yields. Therefore,
engineering of strains with high lipid content relies on novel
concepts such as computational simulation to better understand
the two competing processes and to eliminate citrate
excretion.Using a genome-scale model (GSM) of baker's yeast as
a scaffold, we reconstructed the metabolic network of Y.
lipolytica and optimized it for use in flux balance analysis
(FBA), with the aim to simulate growth and lipid production
phases of this yeast. We validated our model and found the
predictions of the growth behavior of Y. lipolytica in
excellent agreement with experimental data. Based on these
data, we successfully designed a fed-batch strategy to avoid
citrate excretion during the lipid production phase. Further
analysis of the network suggested that the oxygen demand of Y.
lipolytica is reduced upon induction of lipid synthesis.
According to this finding we hypothesized that a reduced
aeration rate might induce lipid accumulation. This prediction
was indeed confirmed experimentally. In a fermentation
combining these two strategies lipid content of the biomass was
increased by 80%, and lipid yield was improved more than
four-fold, compared to standard conditions.Genome scale network
reconstructions provide a powerful tool to predict the effects
of genetic modifications and the metabolic response to
environmental conditions. The high accuracy and the predictive
value of a newly reconstructed GSM of Y. lipolytica to optimize
growth conditions for lipid accumulation are demonstrated.
Based on these findings, further strategies for engineering Y.
lipolytica towards higher efficiency in single cell oil
production are discussed.
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MODEL1510060001.
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2016-01-20 | MODEL1510060001 | BioModels
Project description:Oleaginous yeasts are capable of accumulating high levels of intracellular storage lipids from excess carbon during times when other key nutrients are limited. The basidiomycete yeast Rhodosporidium toruloides is an emerging host for microbial cell factory applications thanks to its naturally high lipid and carotenoid production. However, the engineering toolbox in this non-model host is limited and is currently a bottleneck for implementation of metabolic engineering strategies. In this study, we performed differential gene expression analysis with the goal to identify promoters that are strongly induced or repressed by nitrogen-limitation, a condition that is commonly used to induce lipid accumulation in oleaginous yeasts. The genome-wide transcriptional response of R. toruloides BOT-A2 was analysed using RNAseq during exponential growth and nitrogen-starvation, with either glucose or xylose as the sole carbon source. To validate the differential gene expression findings, reporter genes were constructed by placing the candidate promoters in control of a fluorescent protein, integrated in BOT-A2 and evaluated in vivo.
2023-08-23 | GSE217097 | GEO
Project description:The aim of this work is to investigate whether A. thaliana senses low temperature by perceiving changes in membrane fluidity. To this end, we have performed an experiment to test whether mutant or transgenic plants with altered membrane lipid composition, regulate their gene expression in the same manner as wild type plants in response to cold. Previous work has demonstrated that a change in the expression levels of a number of genes is important in acquiring tolerance to low temperatures. Chemicals which rigidify cell membranes in such a way as to mimic the effects of cold have been shown to be able to induce the expression of such genes. However, because of the non-specific nature of such chemical treatments, it has not been possible to demonstrate unequivocally that the changes in gene expression observed were the result of changes in membrane fluidity. All of the mutants used in our experiment, fab1, fad2-2 and the fad3/fad7/fad8 mutant, have increased lipid saturation levels compared to wild type plants and are thought to have reduced membrane fluidity. The fab1 mutant is also known to be sensitive to chilling. In the fab1 mutant the elongation of 16:0 fatty acids to 18:0 is reduced. The fad2-2 mutant has reduced 18:1 desaturase activity and hence reduced amounts of polyunsaturated phospholipids. The fad3/fad7/fad8 triple mutant is deficient in 18:2 desaturase activity and consequently unable to synthesise trienoic fatty acids. The transgenic line used contained a 35S::FAD3 transgene and in contrast to the mutants tested, should have increased lipid desaturation and increased membrane fluidity. A. thaliana ecotype Col-0 was used as the wild type control for the fab1 and fad2-2 mutants, in addition to the 35S::FAD3 line. The fad3/fad7/fad8 mutant had previously been transformed with the 35S::apoaequorin transgene and a Columbia line expressing apoaequorin under the control of the same promoter, was included to control for the presence of aequorin. Nine day old seedlings grown in petri-dishes on MS were transferred from their growth room (20 oC, 16 h photoperiod, 100 E m-2 s-1) to a growth cabinet (20 oC, 16 h photoperiod,160 m-2 s-1) 24 hours before the experiment began. The next day, one petri-dish of seedlings from each line of plants used was transferred to a cabinet running at 5 oC (16 h photoperiod,160 E m-2 s-1). Control plates remained at 20 oC. Seedlings were harvested after three hours and frozen in liquid nitrogen.
2013-08-30 | GSE50435 | GEO
Project description:The regulation of flocculation, surface adhesion and invasive growth in the fission yeast Schizosaccharomyces pombe has focused primarily at the transcriptional level, but little is known with regards to posttranscriptional control. Here, we identified the Pumilio protein Pfr1 as a novel posttranscriptional regulator of these processes. Deletion of pfr1+ prevented flocculation, surface adhesion and invasive growth under inducing conditions, while overexpression of pfr1+ was sufficient to trigger flocculation. The flocculent phenotype of pfr1+ overexpression was dependent on the presence of the Gsf2 flocculin, but not on the Mbx2, Cbf12 and Adn3 transcription factors. In addition, we used RNA immunoprecipitation and expression microarrays to identify pvg1+ and SPBPB7E8.01, which encode a galactose pyruvyltransferase and glycophosphatidylinositol membrane protein, respectively, as putative mRNA targets potentially degraded by Pfr1. The mRNAs of these genes were upregulated and downregulated in the pfr1 deletion and overexpression strains, respectively, and contained putative binding sites in the 3’-untranslated region. We also discovered that ccr4+ and ste13+, which encode components of the mRNA decay machinery, were required for these processes, but did not suppress the pfr1+ overexpression flocculent phenotype when deleted. This data suggest that these processes in S. pombe involve multiple posttranscriptional-regulatory pathways of which one requires Pfr1.
2016-03-24 | GSE79537 | GEO
Project description:The regulation of flocculation, surface adhesion and invasive growth in the fission yeast Schizosaccharomyces pombe has focused primarily at the transcriptional level, but little is known with regards to posttranscriptional control. Here, we identified the Pumilio protein Pfr1 as a novel posttranscriptional regulator of these processes. Deletion of pfr1+ prevented flocculation, surface adhesion and invasive growth under inducing conditions, while overexpression of pfr1+ was sufficient to trigger flocculation. The flocculent phenotype of pfr1+ overexpression was dependent on the presence of the Gsf2 flocculin, but not on the Mbx2, Cbf12 and Adn3 transcription factors. In addition, we used RNA immunoprecipitation and expression microarrays to identify pvg1+ and SPBPB7E8.01, which encode a galactose pyruvyltransferase and glycophosphatidylinositol membrane protein, respectively, as putative mRNA targets potentially degraded by Pfr1. The mRNAs of these genes were upregulated and downregulated in the pfr1 deletion and overexpression strains, respectively, and contained putative binding sites in the 3â-untranslated region. We also discovered that ccr4+ and ste13+, which encode components of the mRNA decay machinery, were required for these processes, but did not suppress the pfr1+ overexpression flocculent phenotype when deleted. This data suggest that these processes in S. pombe involve multiple posttranscriptional-regulatory pathways of which one requires Pfr1. We generated 2 overexpression microarrays with dye swap that were biological replicates, 2 deletion microarrys with dye swap. Mutants samples were compared to empty vector control or wild type. 1 RIP-chip array was generated with IP rna compared to total RNA from the sample.
2016-03-24 | E-GEOD-79537 | biostudies-arrayexpress
Project description:In the fission yeast Schizosaccharomyces pombe, the transcriptional-regulatory network that governs flocculation remains poorly understood. Here, we systematically screened an array of transcription factor deletion and overexpression strains for flocculation and performed microarray expression profiling and ChIP-chip analysis to identify the flocculin target genes. We identified five transcription factors that displayed novel roles in the activation or inhibition of flocculation (Rfl1, Adn2, Adn3, Sre2, and Yox1), in addition to the previously-known Mbx2, Cbf11 and Cbf12 regulators. Overexpression of mbx2+ and deletion of rfl1+ resulted in strong flocculation and transcriptional upregulation of gsf2+/pfl1+ and several other putative flocculin genes (pfl2+-pfl9+). Overexpression of the pfl+ genes singly was sufficient to trigger flocculation, and enhanced flocculation was observed in several combinations of double pfl+ overexpression. Among the pfl1+ genes, only loss of gsf2+ abrogated the flocculent phenotype of all the transcription factor mutants and prevented flocculation when cells were grown in inducing medium containing glycerol and ethanol as the carbon source, thereby indicating that Gsf2 is the dominant flocculin. In contrast, the mild flocculation of adn2+ or adn3+ overexpression was likely mediated by the transcriptional activation of cell wall-remodeling genes including gas2+, psu1+, and SPAC4H3.03c. We also discovered that Rfl1, Mbx2, and Cbf12 displayed transcriptional autoregulation, and Rfl1 repressed gsf2+ expression in an inhibitory feed-forward loop involving mbx2+. These results reveal that flocculation in S. pombe is regulated by a complex network of multiple transcription factors and target genes encoding flocculins and cell wall-remodeling enzymes. Moreover, comparisons between the flocculation transcriptional regulatory networks of Saccharomyces cerevisiae and S. pombe indicate substantial rewiring of transcription factors and cis-regulatory sequences.
2012-11-02 | GSE41730 | GEO