Light initiates the seedling deetiolation transition by promoting major changes in gene expression mainly regulated by phytochrome (phy) photoreceptors. During the initial dark-to-light transition, phy photoactivation induces rapid changes in gene expression that eventually lead to the photomorphogenic development. Recent reports indicate that this process is achieved by phy-induced degradation of Phy-Interacting bHLH transcription Factors (PIFs) PIF1, PIF3 PIF4 and PIF5, which are partly redundant constitutive repressors of photomorphogenesis that accumulate in darkness. In order to test whether light/phy-regulated gene expression occurs through these PIFs, we have performed whole-genome expression analysis in the pif1pif3pif4pif5 quadruple mutant (pifq).
Definition of early transcriptional circuitry involved in light-induced reversal of PIF-imposed repression of photomorphogenesis in young Arabidopsis seedlings.
No sample metadata fields
View SamplesRNA-seq experiment of WT and pifq mutant seedlings grown for 3 days in darkness in presence or absence of Lincomycin. Overall design: Transcriptome profiles of the wild-type (WT) and pif1pif3pif4pif5 (pifq) quadruple mutant seedlings grown for 3 days in the dark in presence or absence of Lincomycin. Biological triplicate samples were analyzed from libraries constructed using a 3''-capture, 5'' to 3'' directional method.
Phytochrome and retrograde signalling pathways converge to antagonistically regulate a light-induced transcriptional network.
Subject
View SamplesPlants respond to changes in the red:far red ratio (R:FR) of incident light. A reduction in this ratio (increase in FR) results in the Shade Avoidance Response (SAR) with associated changes in gene expression. The Phyotchrome-Interacting Factors (PIFs) are bHLH transcription factors known to be involved in the SAR. An analysis of changes in gene expression in WT and quadruple pif1pif3pif4pif5 (pifq; Leivar et al., 2008 (PMID 19920208)) mutant seedlings in response to an increase in FR should identify primary targets of PIF signaling.
Dynamic antagonism between phytochromes and PIF family basic helix-loop-helix factors induces selective reciprocal responses to light and shade in a rapidly responsive transcriptional network in Arabidopsis.
Specimen part
View SamplesPIF3 plays a role as repressor of photomorphogenesis in darkness. To identify PIF3-regulated genes that might be implementing this action, we have performed whole-genome expression analysis in the pif3 mutant.
Functional profiling identifies genes involved in organ-specific branches of the PIF3 regulatory network in Arabidopsis.
Specimen part
View SamplesOf the members of mitochondrial transcription termination factors (mTERFs) found in metazoans and plants known to regulate organellar gene expression at various levels, plant mTERF6 promotes maturation of a tRNA
Definition of a core module for the nuclear retrograde response to altered organellar gene expression identifies GLK overexpressors as gun mutants.
No sample metadata fields
View SamplesThe PLZF-RARa fusion oncoprotein is overexpressed in the t(11;17) subtype of acute promyelocytic leukemia. Gene expression microarrays were used to identify genes involved in leukemic transformation.
Comprehensive genomic screens identify a role for PLZF-RARalpha as a positive regulator of cell proliferation via direct regulation of c-MYC.
Cell line
View SamplesGUN1 integrates retrograde signals in the chloroplast but the underlying mechanism is elusive. FUG1, a chloroplast translation initiation factor, and GUN1 are co-expressed at the transcript level, and FUG1 co-immunoprecipitates with GUN1. We used mutants of GUN1 (gun1-103) and FUG1 (fug1-3) to analyse their functional relationship at the physiological and systems-wide level, the latter including transcriptome and proteome analyses. Absence of GUN1 aggravates the effects of decreased FUG1 levels on chloroplast protein translation, resulting in transient additive phenotypes with respect to photosynthesis, leaf coloration, growth and cold acclimation. Variegation of the var2 mutant is enhanced by gun1-103 in terms of increasing the fraction of white sectors, in contrast to fug1-3 that acts as suppressor. The transcriptomes of fug1-3 and gun1-103 are very similar, but absence of GUN1 alone has almost no effects on protein levels, whereas chloroplast protein accumulation is markedly decreased in fug1-3. In gun1 fug1 double mutants, effects on transcriptomes and particularly proteomes are enhanced. Our results show that GUN1 function becomes critical when chloroplast proteostasis is perturbed by decreased translation (fug1) or degradation (var2) of chloroplast proteins. The functions of FUG1 and GUN1 appear to be related, corroborating the view that GUN1 operates in chloroplast proteostasis. Overall design: Examination of differential gene expression in the Arabdidopsis thaliana gun1, fug1 and gun1 fug1 mutants compared to wild type in three replicates
Relationship of GUN1 to FUG1 in chloroplast protein homeostasis.
Subject
View SamplesChanges ins organellar gene expression trigger retrograde signalling. Prolyl-tRNA synthetase (PRORS1) is located in chloroplasts and mitochondria. Thus, prors1-2 mutants are impaired in chloroplast and mitochondrial gene expression.
Identification of target genes and transcription factors implicated in translation-dependent retrograde signaling in Arabidopsis.
Age, Specimen part
View SamplesGenes and pathways in which inactivation dampens tissue inflammation present new opportunities for understanding the pathogenesis of common human inflammatory diseases, including inflammatory bowel disease, rheumatoid arthritis and multiple sclerosis. We identified a mutation in the gene encoding the deubiquitination enzyme USP15 (Usp15L749R) that protected mice against both experimental cerebral malaria (ECM) induced by Plasmodium berghei and experimental autoimmune encephalomyelitis (EAE). Combining immunophenotyping and RNA sequencing in brain (ECM) and spinal cord (EAE) revealed that Usp15L749R-associated resistance to neuroinflammation was linked to dampened type I interferon responses in situ. In hematopoietic cells and in resident brain cells, USP15 was coexpressed with, and functionally acted together with the E3 ubiquitin ligase TRIM25 to positively regulate type I interferon responses and to promote pathogenesis during neuroinflammation. The USP15-TRIM25 dyad might be a potential target for intervention in acute or chronic states of neuroinflammation. Overall design: Sequencing of RNA extracted from target tissue in two experimental neuroinflammation models in wild-type (B6), USP15(L749R) and Trim25 KO mutant mice: (1) brains at day 3 and 5 following Plasmodium berghei ANKA (PbA) infection for the cerebral malaria model (ECM); and (2) spinal cords at day 7 following induction of experimental autoimmune encephalomyelitis (EAE) for B6 and Usp15 mutant mice only.
USP15 regulates type I interferon response and is required for pathogenesis of neuroinflammation.
Sex, Specimen part, Treatment, Subject
View SamplesThe in vitro test battery of the European research consortium ESNATS (novel stem cell-based test systems) has been used to screen for potential human developmental toxicants. As part of this effort, the migration of neural crest (MINC) assay has been used to evaluate chemical effects on neural crest function. It identified some drug-like compounds in addition to known environmental toxicants. The hits included the HSP90 inhibitor geldanamycin, the chemotherapeutic arsenic trioxide, the flame-retardant PBDE-99, the pesticide triadimefon and the histone deacetylase inhibitors valproic acid and trichostatin A. Transcriptome changes triggered by these substances in human neural crest cells were recorded and analysed here to answer three questions: (1) can toxicants be individually identified based on their transcript profile; (2) how can the toxicity pattern reflected by transcript changes be compacted/ dimensionality-reduced for practical regulatory use; (3) how can a reduced set of biomarkers be selected for large-scale follow up? Transcript profiling allowed clear separation of different toxicants and the identification of toxicant types in a blinded test study. We also developed a diagrammatic system to visualize and compare toxicity patterns of a group of chemicals by giving a quantitative overview of altered superordinate biological processes (e.g. activation of KEGG pathways or overrepresentation of gene ontology terms). The transcript data were mined for potential markers of toxicity, and 39 transcripts were selected to either indicate general developmental toxicity or distinguish compounds with different modes-of-action in read-across. In summary, we found inclusion of transcriptome data to largely increase the information from the MINC phenotypic test.
Identification of transcriptome signatures and biomarkers specific for potential developmental toxicants inhibiting human neural crest cell migration.
Sex, Specimen part
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