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E-MEXP-729
Hordeum vulgare
9 Downloadable Samples
Affymetrix Barley Genome Array (barley1)
Description
Comparative genomic analysis of nutrient response to NO3-, NH4+ or NH4+: NO3- in barley
Publication Title
Global transcriptional and physiological responses of Saccharomyces cerevisiae to ammonium, L-alanine, or L-glutamine limitation.
Sample Metadata Fields
Age, Specimen part, Subject, Compound
View Samples- Arabidopsis thaliana
- 6 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Despite the importance of amino acids as basic components of proteins, amino acids also serve as substrates for multiple other metabolic pathways, such as the TCA cycle that regulates energy homeostasis. The response to deficiency in the biosynthesis of specific amino acids (also termed “amino acid starvation”) has been studied extensively in yeast (See for example Petti et. al., 2011 Survival of starving yeast is correlated with oxidative stress response and non-respiratory mitochondria function. Proc. Natl. Acad. Sci. USA 108: 1089-1098). In contrast, very little is known about the metabolic responses to deficiency in the biosynthesis of amino acids in plants. A number of recent reports have already shown that catabolism of amino acids can significantly contribute to cellular energy homeostasis particularly during the nighttime and particularly in response to stress. In the present manuscript we used a previously characterized Arabidopsis mutant with reduced expression of the Lys biosynthesis enzyme L,L-diaminopimelate aminotransferase (dapat) to investigate the physiological and metabolic impacts of deficient Lys biosynthesis. The results obtained demonstrate that not stomatal limitations but rather biochemical alterations are responsible for the decreased photosynthesis and growth of the dapat mutants which mimic stress conditions associated to Lys deficiency. Our findings suggest that manipulation of Lys biosynthesis in dapat mutant simulates a stress response culminating in a highly exquisite metabolic reprogramming such that alternative substrates support energy generation once carbohydrate metabolism is down-regulated.
Publication Title
No associated publication
Sample Metadata Fields
Age, Specimen part
View Samples- Homo sapiens
- 12 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Specific vulnerability of neurons in the human entorhinal cortex has been associated with the onset of disease.
Publication Title
Differential gene expression analysis of human entorhinal cortex support a possible role of some extracellular matrix proteins in the onset of Alzheimer disease.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 7 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
Upon antigen recognition within peripheral lymphoid organs, B cells interact with T cells and other immune cells to transiently form morphological structures called germinal centers (GCs), which are required for B cells clonal expansion, immunoglobulin class switching, and affinity maturation. This process, known as the GC response, is an energetically demanding process that requires metabolic reprogramming of B cells. Here, we showed that the Ras-related guanosine triphosphate hydrolase (GTPase) R-Ras2 (also known as TC21) plays an essential, nonredundant, and B cellintrinsic role in the GC response. Both the conversion of B cells into GC B cells and their expansion were impaired in mice lacking R-Ras2, but not in those lacking a highly-related R-Ras subfamily member or both the classic H-Ras and N-Ras GTPases. In the absence of R-Ras2, activated B cells did not increase oxidative phosphorylation or aerobic glycolysis. We showed that R-Ras2 was an effector of both the B cell receptor (BCR) and CD40 and that, in its absence, B cells exhibited impaired activation of the PI3K-Akt-mTORC1 pathway, reduced mitochondrial DNA replication, and decreased expression of genes involved in glucose metabolism. Because most human B cell lymphomas originate from GC B cells or B cells that have undergone the GC response, our data suggests that R-Ras2 may also regulate metabolism in B cell malignancies.
Publication Title
R-Ras2 is required for germinal center formation to aid B cells during energetically demanding processes.
Sample Metadata Fields
Specimen part
View Samples- Arabidopsis thaliana
- 23 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Plant cells contain different O-acetylserine(thiol)lyase (OASTL) enzymes involved in Cys biosynthesis and located in different subcellular compartments. These enzymes are made up of a complex variety of isoforms resulting in different subcellular Cys pools. To unravel the contribution of cytosolic Cys to plant metabolism, we characterized the knockout oas-a1.1 and osa-a1.2 mutants, deficient in the most abundant cytosolic OASTL isoform in Arabidposis thaliana. Total intracellular Cys and glutathione concentrations were reduced, and the glutathione redox state was shifted in favour of its oxidized form. Interestingly, the capability of the mutants to chelate heavy metals did not differ from that of the wild type, but the mutants have an enhanced sensitivity to Cd. With the aim of establishing the metabolic network most influenced by the cytosolic Cys pool, we used the ATH1 GeneChip for evaluation of differentially expressed genes in the oas-a1.1 mutant grown under non-stress conditions. The transcriptomic footprints of mutant plants had predicted functions associated with various physiological responses that are dependent on reactive oxygen species and suggested that the mutant was oxidatively stressed. To further elucidate the specific function(s) of the OAS-A1 isoform in the adaptation response to cadmium we extended the trasncriptome experiment to the wild type and oas-a1.1 mutant plants exposed to Cd. The comparison of transcriptomic profiles showed a higher proportion of genes with altered expression in the mutant than in the wild type, highlighting up-regulated genes identified as of the general oxidative stress response rather than metal-responsive genes.
Publication Title
Knocking out cytosolic cysteine synthesis compromises the antioxidant capacity of the cytosol to maintain discrete concentrations of hydrogen peroxide in Arabidopsis.
Sample Metadata Fields
Specimen part
View Samples- Arabidopsis thaliana
- 12 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Arabidopsis thaliana cells contain different O-acetylserine(thiol)lyase (OASTL) enzymes that catalyze the biosynthesis of cysteine. Recently, we have deeply investigated about one of the minor OASTL-like protein located in the cytosol, named DES1, highlighting some important clues about its metabolic function. We have demonstrated that DES1 catalyzes the desulfuration of L-cysteine to sulfide plus ammonia and pyruvate, instead of the biosynthesis of Cys, and thus, is a novel L-cysteine desulfhydrase (EC 4.4.1.1). The functionality of DES1 is being revealed by the phenotype of the T-DNA insertion mutants des1-1 and des1-2. We have performed a comparative transcriptomic analysis on leaves of the des1-1 and Col-0 wild type plants grown for 30 days under long-day conditions. The normalized data from the replicates showed differential expression of 1614 genes in the des1-1 mutant, with 701 genes down-regulated and 913 genes up-regulated by more than twofold, with a False Discovery Rate (FDR) of < 0.05 and an intensity signal restriction of lgSignal >7. This des1-1 transcriptional profile show a strong alteration when compared to a previous comparative transcriptomic analysis performed on leaves of the des1-1 and Col-0 wild type plants grown for 20 days under identical long-day conditions (GSE 19244). We have also performed a comparative transcriptomic analysis on leaves of the des1-1 and Col-0 wild type plants grown for 20 days and treated with sodium sulfide for 10 additional days. The comparison of the transcriptional profile of des1-1+Na2S versus Col-0+Na2S clearly shows that exogenous sulfide reversed the transcriptional level differences between the mutant and the wild type to reach similar transcriptional patterns as the array GSE19244. Our results suggest a role of sulfide as transcriptional regulator in the des1-1 mutant background.
Publication Title
Cysteine-generated sulfide in the cytosol negatively regulates autophagy and modulates the transcriptional profile in Arabidopsis.
Sample Metadata Fields
Age, Specimen part, Treatment
View Samples- Arabidopsis thaliana
- 12 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Cyanide is stoichiometrically produced as a co-product of the ethylene biosynthesis pathway, and it is detoxified by the b-cyanoalanine synthase enzyme. The molecular and phenotypical analysis of T-DNA insertional mutants of the mitochondrial b-cyanoalanine synthase CYS-C1 suggests that discrete accumulation of cyanide is not toxic for the plant and does not alter mitochondrial respiration rates, but does act as a strong inhibitor of root hair development. The cys-c1 null allele is defective in root hair formation and accumulates cyanide in root tissues. The root hair defect is phenocopied in wild type plants by the exogenous addition of cyanide to the growth medium and is reversed by the addition of hydroxocobalamin. Hydroxocobalamin not only recovers the root phenotype of the mutant, but also the formation of ROS at the initial step of the root hair tip. Transcriptional profile analysis of the cys-c1 mutant reveals that cyanide accumulation acts as a repressor signal for several genes encoding enzymes involved in cell wall rebuilding and the formation of the root hair tip, as well as genes involved in ethylene signaling and metabolism. Our results demonstrate that mitochondrial b-cyanoalanine synthase activity is essential to maintain a low level of cyanide for proper root hair development.
Publication Title
Mitochondrial beta-cyanoalanine synthase is essential for root hair formation in Arabidopsis thaliana.
Sample Metadata Fields
Specimen part
View Samples- Arabidopsis thaliana
- 12 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
In bacteria, the biosynthesis of cysteine is accomplished by two enzymes that are encoged by the cysK and cysM genes. CysM is also able to incorporate thiosulfate to produce S-sulfocysteine. In plant cells, the biosynthesis of cysteine occurs in the cytosol, mitochondria and chloroplasts. Chloroplasts contain two O-acetylserine(thiol)lyase homologs, which are encoded by the OAS-B and CS26 genes. An in vitro enzymatic analysis of the recombinant CS26 protein demonstrated that this isoform possesses S-sulfocysteine synthase activity and lacks O-acetylserine(thiol)lyase activity. In vivo functional analysis of this enzyme in knockout mutants demonstrated that mutation of cs26 suppressed the S-sulfocysteine synthase activity that was detected in wild type; furthermore, the mutants exhibited a growth phenotype, but penetrance depended on the light regime. The cs26 mutant plants also had reductions in chlorophyll content and photosynthetic activity (neither of which were observed in oas-b mutants), as well as elevated glutathione levels. However, cs26 leaves were not able to properly detoxify ROS, which accumulated to high levels under long-day growth conditions. The transcriptional profile of the cs26 mutant revealed that the mutation had a pleiotropic effect on many cellular and metabolic processes. Our finding reveals that S-sulfocysteine and the activity of S-sulfocysteine synthase play an important role in chloroplast function and are essential for light-dependent redox regulation within the chloroplast.
Publication Title
Arabidopsis S-sulfocysteine synthase activity is essential for chloroplast function and long-day light-dependent redox control.
Sample Metadata Fields
No sample metadata fields
View Samples- Arabidopsis thaliana
- 6 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Cysteine occupies a central position in plant metabolism due to its biochemical functions. Arabidopsis thaliana cells contain different O-acetylserine(thiol)lyase (OASTL) enzymes that catalyze the biosynthesis of cysteine. Because they are localized in the cytosol, plastids and mitochondria, this results in multiple subcellular cysteine pools. Much progress has been made on the most abundant OASTL enzymes; however, information on the less abundant OASTL-like proteins has been scarce. To unequivocally establish the enzymatic reaction catalyzed by the minor cytosolic OASTL isoform CS-LIKE (AT5G28030), we expressed this enzyme in bacteria and characterized the purified recombinant protein. Our results demonstrate that CS-LIKE catalyzes the desulfuration of L-cysteine to sulfide plus ammonia and pyruvate. Thus, CS-LIKE is a novel L-cysteine desulfhydrase (EC 4.4.1.1), and we propose to designate it DES1. The impact and functionality of DES1 in cysteine metabolism was revealed by the phenotype of the T-DNA insertion mutants des1-1 and des1-2. Mutation of the DES1 gene leads to premature leaf senescence, as demonstrated by the increased expression of senescence-associated genes and transcription factors. Also, the absence of DES1 significantly reduces the total cysteine desulfuration activity in leaves, and there is a concomitant increase in the total cysteine content. As a consequence, the expression levels of sulfur-responsive genes are de-regulated, and the mutant plants show enhanced antioxidant defenses and tolerance to conditions that promote oxidative stress. Our results suggest that DES1 from Arabidopsis is an L-cysteine desulfhydrase involved in maintaining cysteine homeostasis, mainly at late developmental stages or under environmental perturbations.
Publication Title
Cysteine homeostasis plays an essential role in plant immunity.
Sample Metadata Fields
No sample metadata fields
View Samples- Arabidopsis thaliana
- 16 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
DELLA proteins interact with ARR1 and modulate its activity.
Publication Title
No associated publication
Sample Metadata Fields
Specimen part
View Samples