Saccharomyces cerevisiae strain:IMX745
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ABSTRACT:
PROVIDER: PRJNA313402 | ENA |
REPOSITORIES: ENA
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Project description:Fatty acid synthesis is closely linked to nutrient availability and cellular energetic status. The committed step in fatty acid synthesis is the acetyl CoA carboxylase. Eukaryotes have two genes encoding acetyl CoA carboxylases, one encoding a cytosolic enzyme and another coding for a mitochondrial enzyme. They catalyze the synthesis of malonyl CoA in the cytosol and the mitochondria, respectively. While cytosolic malonyl CoA is the precursor for fatty acid synthesis, mitochondrial malonyl CoA controls the transfer of fatty acyl group into the mitochondria by inhibiting carnitine/palmitoyl transferase activity and thus, regulates β-oxidation. In Saccharomyces cerevisiae, β-oxidation is restricted to the peroxisomes, raising the question of the function of the mitochondrial isoform (HFA1). In this study, we replaced the cytosolic Acc1 with Hfa1 expressed in the cytosol by removing the mitochondrial leader peptide, under control of the HFA1 promoter. We studied fatty acid synthesis and transcription profiles in this strain during starvation for carbon or nitrogen, using glucose or ethanol as the carbon source. Under all the conditions studied, the key sensor of energetic status, Snf1, was activated, indicating active inhibition of fatty acid synthesis. The pool size of fatty acids was smaller when Acc1 was replaced with truncated Hfa1 for fatty acid synthesis. Yet, the transcription profiles were similar in both the cases. These results point towards the conclusion that Hfa1 is either catalytically less efficient or it is more sensitive to inhibition by Snf1. Gene expression from a strain of Saccharomyces cerevisiae where cytosolic fatty acid synthesis occurs by mitochondrial acetyl CoA carboxylase (without its mitochondrial leader peptide) is compared with that in a reference strain while growing in chemostats on carbon or nitrogen starvation using glucose or ethanol as the carbon source. There are two strains (reference or mutant), two carbon sources (glucose or ethanol) and two limitations (carbon or nitrogen), resulting in 8 comparisons. Each array was performed in duplicate, resulting in 16 CEL files. Growth was limited by either carbon or nitrogen. When carbon was the limited nutrient, we tested growth on either glucose or ethanol (both using ammonium sulfate as the nitrogen source). When ammonium sulfate was limiting, we used either glucose or ethanol as the carbon source.
2010-06-08 | E-GEOD-21988 | biostudies-arrayexpress
Project description:Microarray analysis of the effect of L-carnitine supplementation on global expression of Sachharomyces cerevisiae cultures in logarithmic growing conditions and after exposure to H2O2 induced oxidative stress L-Carnitine plays a well documented role in eukaryotic energy homeostasis by acting as a shuttling molecule for activated acyl residues across intracellular membranes. This activity is supported by carnitine acyl-transferases and transporters, and is referred to as the carnitine shuttle. However, several pleiotropic and often beneficial effects of carnitine in humans have been reported that appear to be unrelated to the shuttling activity, but little conclusive evidence regarding the molecular networks that would be affected by carnitine exist. We have recently demonstrated a protective role of carnitine in oxidative stress in yeast that is independent of the carnitine shuttle. A DNA microarray-based global gene expression analysis identified Cyc3p, a cytochrome c heme lyase, as being important for carnitine's protective impact in oxidative stress conditions. These findings establish a direct genetic link to a carnitine-related phenotype that is independent of the shuttle system. The data suggest that the yeast Saccharomyces cerevisiae should provide a useful model for further elucidation of carnitine's physiological roles.
2009-06-29 | GSE16346 | GEO
Project description:Fatty acid synthesis is closely linked to nutrient availability and cellular energetic status. The committed step in fatty acid synthesis is the acetyl CoA carboxylase. Eukaryotes have two genes encoding acetyl CoA carboxylases, one encoding a cytosolic enzyme and another coding for a mitochondrial enzyme. They catalyze the synthesis of malonyl CoA in the cytosol and the mitochondria, respectively. While cytosolic malonyl CoA is the precursor for fatty acid synthesis, mitochondrial malonyl CoA controls the transfer of fatty acyl group into the mitochondria by inhibiting carnitine/palmitoyl transferase activity and thus, regulates β-oxidation. In Saccharomyces cerevisiae, β-oxidation is restricted to the peroxisomes, raising the question of the function of the mitochondrial isoform (HFA1). In this study, we replaced the cytosolic Acc1 with Hfa1 expressed in the cytosol by removing the mitochondrial leader peptide, under control of the HFA1 promoter. We studied fatty acid synthesis and transcription profiles in this strain during starvation for carbon or nitrogen, using glucose or ethanol as the carbon source. Under all the conditions studied, the key sensor of energetic status, Snf1, was activated, indicating active inhibition of fatty acid synthesis. The pool size of fatty acids was smaller when Acc1 was replaced with truncated Hfa1 for fatty acid synthesis. Yet, the transcription profiles were similar in both the cases. These results point towards the conclusion that Hfa1 is either catalytically less efficient or it is more sensitive to inhibition by Snf1. Gene expression from a strain of Saccharomyces cerevisiae where cytosolic fatty acid synthesis occurs by mitochondrial acetyl CoA carboxylase (without its mitochondrial leader peptide) is compared with that in a reference strain while growing in chemostats on carbon or nitrogen starvation using glucose or ethanol as the carbon source.
2010-05-25 | GSE21988 | GEO
Project description:Microarray analysis of the effect of L-carnitine supplementation on global expression of Sachharomyces cerevisiae cultures in logarithmic growing conditions and after exposure to H2O2 induced oxidative stress; L-Carnitine plays a well documented role in eukaryotic energy homeostasis by acting as a shuttling molecule for activated acyl residues across intracellular membranes. This activity is supported by carnitine acyl-transferases and transporters, and is referred to as the carnitine shuttle. However, several pleiotropic and often beneficial effects of carnitine in humans have been reported that appear to be unrelated to the shuttling activity, but little conclusive evidence regarding the molecular networks that would be affected by carnitine exist. We have recently demonstrated a protective role of carnitine in oxidative stress in yeast that is independent of the carnitine shuttle. A DNA microarray-based global gene expression analysis identified Cyc3p, a cytochrome c heme lyase, as being important for carnitine's protective impact in oxidative stress conditions. These findings establish a direct genetic link to a carnitine-related phenotype that is independent of the shuttle system. The data suggest that the yeast Saccharomyces cerevisiae should provide a useful model for further elucidation of carnitine's physiological roles. Experiment Overall Design: Yeast cultures was grown to mid-log phase with and without carnitine supplementation to a final concentration of 100 mg/L. A second set was grown to mid log phase, with and without carnitine supplementation and exposed to 0.4 mM H2O2 for 30 min. The experiments were performed using biological duplicate.
2009-07-04 | E-GEOD-16346 | biostudies-arrayexpress
Project description:Carnitine acetyltransferase (CRAT) is a mitochondrial enzyme and catalyzes the conversion of acetyl-CoA to acetyl-Carnitine, which enables its export from mitochondria. It was reported that CRAT played a central role in regulating metabolic flexibility and promoting substrate switching from fatty acid to glucose in skeletal myocytes5. Interestingly, CRAT is most abundantly expressed in the heart and its activity is dramatically decreased in the mouse model of HF5,9. However, the specific contribution of this enzyme in the pathogenesis of HF remains largely uncharacterized.
2023-06-02 | GSE200057 | GEO
Project description:Partitioning of active gene loci to the nuclear envelope is a key mechanism by which organisms can increase the speed of adaptation and metabolic robustness to fluctuating resources in the environment. In the budding yeast Saccharomyces cerevisiae, adaptation and transcriptional memory induced by nutrient depletion or other stresses, results from relocalization of active gene loci from nucleoplasm to the nuclear envelope, leading to increased transport of mRNAs to the cytosol and their translation. The mechanism by which this translocation occurs remains a mystery. We show here, that for the inositol depletion-responsive gene locus INO1 in yeast, translocation to the nuclear envelope is caused by a local phase transition of the mechanical stiffness of chromatin surrounding activated INO1 that favors phase separation of the active gene locus into low density regions of chromatin proximal to the nuclear envelope. Gene regulatory elements essential to translocation encode binding sites for histone acetyl transferases, which are necessary for chromatin decompaction. INO1 locus partitioning can be explained by a phenomenological model of chromatin decompaction, which reflects stiffening of chromatin and its partitioning into a dilute chromatin phase adjacent to the nuclear envelope, from the dense chromatin found in the nucleoplasmic phase. Recent evidence suggests that this demixing of chromatin could be due to the dissolution of multivalent chromatin interactions mediated by histone post-translational modifications.
2023-03-01 | PXD029913 | Pride
Project description:The energetic (ATP) cost of biochemical pathways critically determines the maximum yield of metabolites of vital or commercial relevance. Cytosolic acetyl-CoA is a key precursor for biosynthesis in eukaryotes and for many industrially relevant product pathways that have been introduced into Saccharomyces cerevisiae, such as isoprenoids or lipids. In this yeast, synthesis of cytosolic acetyl-CoA via acetyl-CoA synthetase (ACS) involves hydrolysis of ATP to AMP and pyrophosphate. Here, we demonstrate that expression and assembly in the yeast cytosol of a pyruvate dehydrogenase complex (PDH) from Enterococcus faecalis can fully replace the ACS-dependent pathway for cytosolic acetyl-CoA synthesis. In vivo activity of E. faecalis PDH required the simultaneous expression of E. faecalis genes encoding its E1α, E1β, E2 and E3 subunits, as well as genes involved in lipoylation of E2 and addition of lipoate to growth media. A strain lacking ACS, that expressed these E. faecalis genes, grew at near-wild-type rates on glucose synthetic medium supplemented with lipoate, under aerobic and anaerobic conditions. A physiological comparison of the engineered strain and an isogenic Acs+ reference strain showed small differences in biomass yields and metabolic fluxes. Cellular fractionation and gel filtration studies revealed that the E. faecalis PDH subunits were assembled in the yeast cytosol, with a subunit ratio and enzyme activity similar to values reported for PDH purified from E. faecalis. This study indicates that cytosolic expression and assembly of PDH in eukaryotic industrial micro-organisms is a promising option for minimizing the energy costs of precursor supply in acetyl-CoA-dependent product pathways. For both strains - mutant strain IMY104 and reference strain CEN.PK113-7D' three independent chemostat cultures were performed. Each of the chemosta was sampled for transcriptome analysis. Samples were processed as described below.
2014-11-04 | E-GEOD-59814 | biostudies-arrayexpress
Project description:Correct intracellular distribution of proteins is critical for the function of eukaryotic cells. Certain proteins are targeted to more than one cellular compartment, e.g. to mitochondria and peroxisomes. The protein phosphatase Ptc5 from Saccharomyces cerevisiae contains an N-terminal mitochondrial presequence followed by a trans-membrane domain and has been detected in the mitochondrial intermembrane space. Here we show mitochondrial transit of Ptc5 to peroxisomes. Translocation of Ptc5 to peroxisomes depended both on the C-terminal peroxisomal targeting signal (PTS1) and N-terminal cleavage by the mitochondrial inner membrane peptidase complex. Indirect targeting of Ptc5 to peroxisomes prevented deleterious effects of its phosphatase activity in the cytosol. Sorting of Ptc5 involves simultaneous interaction with import machineries of both organelles. We identify additional mitochondrial proteins with PTS1, which localize in both organelles and can increase their physical association. Thus, a tug-of-war like mechanism can influence the interaction and communication of two cellular compartments.
2020-05-22 | PXD018591 | Pride
Project description:Mitochondria fulfil many essential roles in eukaryotic cells, yet some of their molecular mechanisms are still unexplored. Although 99% of the mitochondrial proteins are imported from the cytosol, mitochondria have their own DNA, transcription and translation machinery. The Saccharomyces cerevisiae mitochondrial DNA contains 11 polycistronic transcripts that encode 2 ribosomal subunits, 24 tRNAs and 9 genes, which can be spliced in alternative ways to yield different proteins. There are still many unresolved questions about mitochondrial genes and their splicing, including how gene expression and splicing is affected by different growth conditions and what role introns play in mitochondrial physiology. In the present study, we aimed to elucidate this by developing an RNA-sequencing method for mitochondrial RNA using Nanopore technology.
2023-11-21 | GSE219013 | GEO
Project description:Circadian rhythmicity in renal function suggests rhythmic adaptations in renal metabolism. To decipher the role of the circadian clock in renal metabolism, we studied diurnal changes in renal metabolic pathways using integrated transcriptomic, proteomic, and metabolomic analysis performed on control mice and mice with inducible deletion of the circadian clock regulator Bmal1 in the renal tubule (cKOt). With this unique resource, we demonstrated that ~30% RNAs, ~20% proteins and ~20% metabolites are rhythmic in kidneys of control mice. Several key metabolic pathways including NAD+ biosynthesis, fatty acid transport, carnitine shuttle, and b-oxidation displayed impairments in kidneys of cKOt, resulting in a perturbed mitochondrial activity. Carnitine reabsorption from the primary urine was one of the most impacted processes with a ~50% reduction in plasma carnitine levels and a parallel systemic decrease in tissues carnitine content. This suggests that the circadian clock in the renal tubule controls both kidney and systemic physiology.
2023-03-05 | GSE216252 | GEO