Protein synthesis belongs to the most energy consuming processes in the cell. Lowering oxygen tension below normal (hypoxia) causes a rapid inhibition of global mRNA translation due to the decreased availability of energy. Interestingly, subsets of mRNAs pursue active translation under such circumstances. In human fibrosarcoma cells (HT1080) exposed to prolonged hypoxia (36 h, 1% oxygen) we observed that transcripts are either increasingly or decreasingly associated with ribosomes localized at the endoplasmic reticulum (ER). In a global setting it turned out that only 31% of transcripts showing elevated total-RNA levels were also increasingly present at the ER in hypoxia. These genes, regulated by its expression as well as its ER-localization, belong to the gene ontologys hypoxia response, glycolysis and HIF-1 transcription factor network supporting the view of active mRNA translation at the ER during hypoxia. Interestingly, a large group of RNAs was found to be unchanged at the expression level, but translocate to the ER in hypoxia. Among these are transcripts encoding translation factors and >180 ncRNAs. In summary, we provide evidence that protein synthesis is favoured at the ER and, thus, partitioning of the transcriptome between cytoplasmic and ER associated ribosomes mediates adaptation of gene expression in hypoxia.
Hypoxia-induced gene expression results from selective mRNA partitioning to the endoplasmic reticulum.
Specimen part, Cell line
View SamplesWe used microarray analysis to investigate if keratinocytes excert an immuno-inflammatory response towards streptococcal M1 protein.
Vigilant keratinocytes trigger pathogen-associated molecular pattern signaling in response to streptococcal M1 protein.
Specimen part, Cell line
View SamplesA biobank collection of carotid plaque samples taken from patients undergoing endarterectomy operations.
Prediction of ischemic events on the basis of transcriptomic and genomic profiling in patients undergoing carotid endarterectomy.
Specimen part, Disease, Subject
View SamplesSTO2 is a novel MYB like protein which belongs to one of the most important transcription factors in planta.
Salt-Related MYB1 Coordinates Abscisic Acid Biosynthesis and Signaling during Salt Stress in Arabidopsis.
Specimen part
View SamplesPlants typically contain two different types of cell walls: a primary wall that is being deposited around all growing cells, and a secondary wall that is produced in cells with specialized functions once they have ceased to grow. In Arabidopsis, VND7 is a transcription factor that is sufficient to activate secondary cell wall synthesis. To artificially turn on the secondary cell wall synthesis, VND7 was fused to the activation domain of the herpes virus VP16 protein and the glucocorticoid receptor (GR) domain. Thus, the transgenic plants harbouring the constructs can then be treated with dexamethasone (DEX), a glucocorticoid derivative, to induce the secondary cell wall formation.
A Transcriptional and Metabolic Framework for Secondary Wall Formation in Arabidopsis.
Specimen part, Treatment
View SamplesRenal hypoxia is widespread in acute kidney injury (AKI) of various aetiologies. Hypoxia adaptation, conferred through the hypoxia-inducible factor (HIF), appears to be insufficient. Here we show that HIF activation in renal tubules through Pax8-rtTA-based inducible knockout of von Hippel-Lindau protein (VHL-KO) protects from rhabdomyolysis-induced AKI. In this model, histological observations indicate that injury mainly affects proximal convoluted tubules, with 5% necrosis at d1 and 40% necrosis at d2. HIF-1alpha up-regulation in distal tubules reflects renal hypoxia. However, lack of HIF in proximal tubules suggests insufficient adaptation by HIF.
Tubular von Hippel-Lindau knockout protects against rhabdomyolysis-induced AKI.
Specimen part, Disease, Disease stage, Treatment
View SamplesTo understand how an inhibition of the mitochondrial ATP synthase affects transcriptional programming and to identify potential candidates of the signaling machinery involved in ATP synthase deficiency responses, we used oligomycin on seedling liquid cultures. Seedlings were harvested at time points 0, 1 and 4 h after the start of oligomycin and control (EtOH) treatments. Already 1 h after addition of oligomycin a total of 102 genes were more than threefold up-regulated and 14 genes were repressed, with most of them showing persistent changes. After 4 h, 580 additional genes were more than threefold up-regulated, and 152 genes were repressed by oligomycin. Several genes for alternative NAD(P)H dehydrogenases and alternative oxidases (AOX1a, AOX1d and NDA1) were up-regulated early, and additional homologs (NDA2, NDB2, NDB4 and AOX1b) followed 4 h after the start of treatment. Several genes for subunits of complex I, complex IV and the ATP synthase were induced whereas hardly any genes encoding enzymes of glycolysis and the TCA cycle changed. Additionally, four of five hallmark genes for oxidative stress were increased by oligomycin. These genes are At2g21640 (UPOX), At1g19020, At1g05340 and At1g57630 and code for proteins of unknown function. Among oxidative stress proteins with known functions, several H2O2-responsive Glutathione-S-transferases and BCS1 (CYTOCHROME BC1 SYNTHESIS) were strongly up-regulated already after 1 h. BCS1 is induced by salicylic acid and independent of other reactive oxygen signaling (ROS) pathways, such as H2O2. The results indicate that several different ROS and defense signaling pathways were induced simultaneously by oligomycin. This is further corroborated by induction of several transcription factors of the WRKY and NAC families, which have been previously implicated in coordinating cellular defense signaling.
Downregulation of the δ-subunit reduces mitochondrial ATP synthase levels, alters respiration, and restricts growth and gametophyte development in Arabidopsis.
Specimen part, Treatment
View SamplesUpon illumination, etiolated seedlings experience a transition from heterotrophic to photoautotrophic growth. During this process, the tetrapyrrole biosynthesis pathway provides chlorophyll for photosynthesis. This pathway has to be tightly controlled to prevent the accumulation of photoreactive metabolites and to provide stoichiometric amounts of chlorophyll for its incorporation into photosynthetic protein complexes. Therefore, plants have evolved regulatory mechanisms to synchronize the biosynthesis of chlorophyll and chlorophyll-binding proteins. Two phytochrome-interacting factors (PIF1 and PIF3) and the DELLA proteins, which are controlled by the gibberellin pathway, are key regulators of this process. Here, we show that impairment of TARGET OF RAPAMYCIN (TOR) activity in Arabidopsis (Arabidopsis thaliana), either by mutation of the TOR complex component RAPTOR1B or by treatment with TOR inhibitors, leads to a significantly reduced accumulation of the photoreactive chlorophyll precursor protochlorophyllide in darkness but an increased greening rate of etiolated seedlings after exposure to light. Detailed profiling of metabolic, transcriptomic, and physiological parameters revealed that the TOR-repressed lines not only grow slower, they grow in a nutrient-saving mode, which allows them to resist longer periods of low nutrient availability. Our results also indicated that RAPTOR1B acts upstream of the gibberellin-DELLA pathway and its mutation complements the repressed greening phenotype of pif1 and pif3 after etiolation.
Inhibition of TOR Represses Nutrient Consumption, Which Improves Greening after Extended Periods of Etiolation.
Specimen part, Treatment
View SamplesCell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1), was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic organ fusions. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246). Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion.
The FRIABLE1 gene product affects cell adhesion in Arabidopsis.
Specimen part
View SamplesTo comprehensively characterize microRNA (miRNA) expression in breast cancer, we performed the first extensive next-generation sequencing expression analysis of this disease. We sequenced small RNA from tumors with paired samples of normal and tumor-adjacent breast tissue. Our results indicate that tumor identity is achieved mainly by variation in the expression levels of a common set of miRNAs rather than by tissue-specific expression. We also report 361 new, well-supported miRNA precursors. Nearly two-thirds of these new genes were detected in other human tissues and 49% of the miRNAs were found associated with Ago2 in MCF7 cells. Ten percent of the new miRNAs are located in regions with high-level genomic amplifications in breast cancer. A new miRNA is encoded within the ERBB2/Her2 gene and amplification of this gene leads to overexpression of the new miRNA, indicating that this potent oncogene and important clinical marker may have two different biological functions. In summary, our work substantially expands the number of known miRNAs and highlights the complexity of small RNA expression in breast cancer. Overall design: Sequencing of approximately 18-35 nt small RNAs from paired samples of normal, tumor and tumor-adjacent tissue for five breast cancer patients
Identification of new microRNAs in paired normal and tumor breast tissue suggests a dual role for the ERBB2/Her2 gene.
Specimen part, Subject
View Samples