Nitrogen (N) and nitrate (NO3-) per se regulate many aspects of plant metabolism, growth and development. N/NO3- also suppresses parts of secondary metabolism including anthocyanin synthesis. Molecular components for this repression are unknown. We report that three N/NO3--induced members of the LATERAL ORGAN BOUNDARY DOMAIN (LBD) gene family of transcription factors (LBD37, LBD38 and LBD39) act as negative regulators of anthocyanin biosynthesis in Arabidopsis (Arabidopsis thaliana). Over-expression of each of the three genes in the absence of N/NO3- strongly suppresses the key regulators of anthocyanin synthesis PAP1 and PAP2, genes in the anthocyanin-specific part of flavonoid synthesis, as well as cyanidin- but not quercetin- or kaempferol-glycoside production. Conversely, lbd37, lbd38 or lbd39 T-DNA insertion mutants accumulate anthocyanins when grown in N/NO3--sufficient conditions and show constitutive expression of anthocyanin biosynthetic genes. The LBD genes also repress many other known N-responsive genes including key genes required for NO3- uptake and assimilation, resulting in altered NO3- content, nitrate reductase activity/activation, protein, amino acid and starch levels, and N-related growth phenotypes. The results identify LBD37 and its two close homologs as novel repressers of anthocyanin biosynthesis and N-availability signals in general. They also show that besides being developmental regulators LBD genes fulfill roles in metabolic regulation.
Members of the LBD family of transcription factors repress anthocyanin synthesis and affect additional nitrogen responses in Arabidopsis.
Age, Specimen part, Treatment
View SamplesAbiotic stress is a major factor for crop productivity, a problem likely to be exacerbated by climate change. Improving the tolerance to environmental stress is one of the most important goals of crop breeding programmes. While the early responses to abiotic stress in plants are well studied, plant adaptation to enduring or recurring stress conditions has received little attention. This project investigates the molecular mechanism of the maintenance of acquired thermotolerance as a model case of stress memory in Arabidopsis. Arabidopsis seedlings acquire thermotolerance through a heat treatment at sublethal temperatures. To investigate the underlying mechanisms, we are investigating changes in the transcriptome at two timepoints after a heat acclimation treatment using Arabidopsis thaliana seedlings.
Arabidopsis miR156 Regulates Tolerance to Recurring Environmental Stress through SPL Transcription Factors.
Treatment
View SamplesSulphur is an essential macronutrient for plant growth and development. Reaching a thorough understanding of the molecular basis for changes in plant metabolism depending on the sulphur-nutritional status at the systems level will advance our basic knowledge and help target future crop improvement. Although the transcriptional responses induced by sulphate starvation have been studied in the past, knowledge of the regulation of sulphur metabolism is still fragmentary. This work focuses on the discovery of candidates for regulatory genes such as transcription factors (TFs) using omics technologies. For this purpose a short term sulphate-starvation / re-supply approach was used. ATH1 microarray studies and metabolite determinations yielded 21 TFs which responded more than 2-fold at the transcriptional level to sulphate starvation. Categorization by response behaviors under sulphate-starvation / re-supply and other nutrient starvations such as nitrate and phosphate allowed determination of whether the TF genes are specific for or common between distinct mineral nutrient depletions. Extending this co-behavior analysis to the whole transcriptome data set enabled prediction of putative downstream genes. Additionally, combinations of transcriptome and metabolome data allowed identification of relationships between TFs and downstream responses, namely, expression changes in biosynthetic genes and subsequent metabolic responses. Effect chains on glucosinolate and polyamine biosynthesis are discussed in detail. The knowledge gained from this study provides a blueprint for an integrated analysis of transcriptomics and metabolomics and application for the identification of uncharacterized genes.
Transcriptome and metabolome analysis of plant sulfate starvation and resupply provides novel information on transcriptional regulation of metabolism associated with sulfur, nitrogen and phosphorus nutritional responses in Arabidopsis.
Specimen part
View SamplesGenetically engineered mice developed spontaneous pancreas cancer (Pdx-Cre;LSL-KRASG12D;P53Mut). Mice were also engineered to develop similar spontaneous pancreas cancer without Twist or Snail (conditional gene knockout). The pancreas tumors were harvested and analysed for gene expression profiles comparisons.
Epithelial-to-mesenchymal transition is dispensable for metastasis but induces chemoresistance in pancreatic cancer.
Specimen part
View SamplesHow do the transcript levels of leaf-expressed genes change in a normal day-night cycle? The interest is in genes that are regulated by the circadian clock and the diurnal component (i.e. light, metabolite changes). Plants were grown on soil in a 12/12 h light/dark rythm at 20C day and night. 5 weeks after germination the rosettes of the non-flowering plants were harvested, 15 plants per sample. Plants were harvested at 6 timepoints every 4 hours beginning with the end of the night (still in darkness).
Sugars and circadian regulation make major contributions to the global regulation of diurnal gene expression in Arabidopsis.
No sample metadata fields
View SamplesmRNA sequencing was used to identify genome wide transcriptional changes occuring in fly heads in response to spermidine feeding. This study shed light on the molecular mechanisms through wich spermidine can protect against age-dependent memory impairment. Overall design: mRNA profiles from 3 and 10 day old Drosophila melanogaster heads were generated in duplicate by deep sequencing using Illumina GAIIx. mRNA profiles from flies that were fed food with 5mM spermidine were compared to profiles from flies that had no spermidine in thier food.
Restoring polyamines protects from age-induced memory impairment in an autophagy-dependent manner.
Age, Specimen part, Subject
View SamplesTo compare human memory CD4+ T cell subsets in peripheral blood (PB) and bone marrow (BM) of healthy individuals at transcriptional level, we analyzed the global gene expression of ex vivo PB CD69- as well as BM CD69- and CD69+ memory CD4+ T cells from 4 paired PB and BM samples. The gene expression of these subsets was additionally compared to the transcriptional profile of 8 PB samples taken ex vivo or stimulated with phorbol myristate acetate (PMA) and Ionomycin for 3 hours.
Human memory T cells from the bone marrow are resting and maintain long-lasting systemic memory.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Importance of Comprehensive Molecular Profiling for Clinical Outcome in Children With Recurrent Cancer.
No sample metadata fields
View Samplesto explore possible treatment targets and reasons for agressive children cacners by comprehensive molecular profiling on several platforms
Importance of Comprehensive Molecular Profiling for Clinical Outcome in Children With Recurrent Cancer.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Defective mitophagy in XPA via PARP-1 hyperactivation and NAD(+)/SIRT1 reduction.
Sex, Cell line, Treatment
View Samples