Post-transcriptional regulation of mRNA by the RNA binding protein HuR is required in B cells for the germinal centre reaction and for the production of class-switched antibodies in response to T-independent antigens. Transcriptome-wide examination of RNA isoforms, abundance and translation in HuR-deficient B cells, together with direct measurements of HuR-RNA interaction, revealed that HuR-dependent mRNA splicing affects hundreds of transcripts including the dihydrolipoyl succinyltransferase (Dlst), a subunit of the aketoglutaratedehydrogenase (aKGDH) enzyme. In the absence of HuR, defective mitochondrial metabolism results in high levels of reactive oxygen species and B cell death. Our study shows how post-transcriptional processes control the balance of energy metabolism required for B cell proliferation and differentiation. Overall design: Sequencing analysis of B cell transcriptome using Illumina TruSeq mRNA sample prep kit and Illumina platform. RNA was isolated from ex-vivo or LPS-activated (48h) splenic B cells from HuRflox/flox x mb1wt control or HuRflox/flox x mb1cre mice. 3-4 biological replicates per genotype and condition.
The RNA-binding protein HuR is essential for the B cell antibody response.
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View SamplesIn T-cell acute lymphoblastic leukemia (T-ALL) NOTCH 1 receptors are frequently mutated. This leads to aberrantly high Notch signaling, but how this translates into deregulated cell cycle control and the transformed cell type is poorly understood. In this report, we analyze downstream responses resulting from the high level of NOTCH 1 signaling in T-ALL. Notch activity, measured immediately downstream of the NOTCH 1 receptor, is high, but expression of the canonical downstream Notch response genes HES 1 and HEY 2 is low both in primary cells from T-ALL patients and in T-ALL cell lines. This suggests that other immediate Notch downstream genes are activated, and we found that Notch signaling controls the levels of expression of the E3 ubiquitin ligase SKP2 and its target protein p27Kip1. We show that in T-ALL cell lines, recruitment of NOTCH 1 ICD to the SKP2 promoter was accompanied by high SKP2 and low p27Kip1 protein levels were low. In contrast, pharmacologically blocking Notch signaling reversed this picture and led to loss of NOTCH 1 ICD occupancy of the SKP2 promoter, decreased SKP2 and increased p27Kip1 expression. T-ALL cells show a rapid G1-S cell cycle transition, while blocked Notch signaling resulted in G0/G1 cell cycle arrest, also observed by transfection of p27Kip1 or, to a smaller extent, a dominant negative SKP2 allele. Collectively, our data suggest that the aberrantly high Notch signaling in T-ALL maintains SKP2 at a high level and reduces p27Kip1, which leads to more rapid cell cycle progression.
Notch signaling induces SKP2 expression and promotes reduction of p27Kip1 in T-cell acute lymphoblastic leukemia cell lines.
No sample metadata fields
View SamplesMacrophage activation by bacterial lipopolysaccharides (LPS) is induced through Toll-like receptor 4 (TLR4). The synthesis and activity of TLR4 downstream signalling molecules modulates the expression of pro- and anti-inflammatory cytokines. To address the impact of post-transcriptional regulation on that process, we performed RIP-Chip analysis. Differential association of mRNAs with heterogeneous ribonucleoprotein K (hnRNP K), an mRNA-specific translational regulator in differentiating haematopoietic cells, was studied in non-induced and LPS-activated macrophages. Analysis of interactions affected by LPS revealed an enrichment of mRNAs encoding TLR4 downstream kinases and their modulators. We focused on transforming growth factor activated kinase-1 (TAK1), a central player in TLR4 signalling. HnRNP K interacts specifically with a sequence in the TAK1 mRNA 3' UTR in vitro. Silencing of hnRNP K does not affect TAK1 mRNA synthesis and stability, but enhances TAK1 mRNA translation, resulting in elevated TNF-alpha, IL-1beta and IL-10 mRNA expression. Our data suggest that the hnRNP K-3' UTR complex inhibits TAK1 mRNA translation in non-induced macrophages. LPS-dependent TLR4 activation abrogates translational repression and newly synthesised TAK1 initiates the inflammatory response of macrophages.
Translation control of TAK1 mRNA by hnRNP K modulates LPS-induced macrophage activation.
Specimen part, Cell line, Treatment
View SamplesThis experiment was set up in order to identify the (direct) transcriptional targets of the Ethylene Response Factor 115 (ERF115) transcription factor. Because ERF115 expression occurs in quiescent center (QC) cells and strong effects on the QC cells were observed in ERF115 overexpression plants, root tips were harvested for transcript profiling in order to focus on root meristem and QC specific transcriptional targets.
ERF115 controls root quiescent center cell division and stem cell replenishment.
Age, Specimen part
View SamplesThe intercalated disc of cardiac myocytes is emerging as a crucial structure in the heart. Loss of intercalated disc proteins like N-cadherin causes lethal cardiac abnormalities, mutations in intercalated disc proteins cause human cardiomyopathy. A comprehensive screen for novel mechanisms in failing hearts demonstrated that expression of the lysosomal integral membrane protein-2 (LIMP-2) is increased in cardiac hypertrophy and heart failure in both rat and human myocardium. Complete loss of LIMP-2 in genetically engineered mice did not affect cardiac development; however these LIMP-2 null mice failed to mount a hypertrophic response to increased blood pressure but developed cardiomyopathy. Disturbed cadherin localization in these hearts suggested that LIMP-2 has important functions outside lysosomes. Indeed, we also find LIMP-2 in the intercalated disc, where it associates with cadherin. RNAi-mediated knockdown of LIMP-2 decreases the binding of phosphorylated b-catenin to cadherin, while overexpression of LIMP-2 has the opposite effect. Taken together, our data show that lysosomal integrated membrane protein-2 is crucial to mount the adaptive hypertrophic response to cardiac loading. We demonstrate a novel role for LIMP-2 as an important mediator of the intercalated disc.
Lysosomal integral membrane protein 2 is a novel component of the cardiac intercalated disc and vital for load-induced cardiac myocyte hypertrophy.
No sample metadata fields
View SamplesWounding is a primary trigger of organ regeneration but how wound stress reactivates cell proliferation and promotes cellular reprogramming remains elusive. In this study we combined the transcriptome analysis with quantitative hormonal analysis to investigate how wounding induces callus formation in Arabidopsis thaliana. Our time-course RNA-seq analysis revealed that wounding induces dynamic transcriptional changes that can be categorized into five clusters with distinct temporal patterns. Gene ontology analyses uncovered that wounding modifies the expression of hormone biosynthesis and response genes, and quantitative analysis of endogenous plant hormones revealed accumulation of cytokinin prior to callus formation. Mutants defective in cytokinin synthesis and signalling display reduced efficiency in callus formation, indicating that de novo synthesis of cytokinin has major contribution in wound-induced callus formation. We further demonstrate that type-A ARABIDOPSIS RESPONSE REGULATOR (ARR)-mediated cytokinin signalling regulates the expression of CYCLIN D3;1 (CYCD3;1) and mutations in CYCD3;1 and its homologs CYCD3;2-3 cause defects in callus formation. Our transcriptome data, in addition, showed that wounding activates multiple developmental regulators, and we found novel roles of ETHYLENE RESPONSE FACTOR 115 (ERF115) and PLETHORA3 (PLT3), PLT5, PLT7 in wound-induced callus formation. Together, this study provides novel mechanistic insights into how wounding reactivates cell proliferation during callus formation. Overall design: Examination of transcriptome at 0, 1, 3, 6, 12,24 h after wounding.
Wounding Triggers Callus Formation via Dynamic Hormonal and Transcriptional Changes.
Specimen part, Subject, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide signatures of differential DNA methylation in pediatric acute lymphoblastic leukemia.
Specimen part, Disease, Disease stage
View SamplesWe surveyed the genome-wide DNA methylation levels and gene expression patterns in patients with pediatric acute lymphoblastic leukemia. Using Affymetrix U133 Plus 2.0 GeneChips, we identified a relatively small set of CpG sites that are highly correlated with gene expression.
Genome-wide signatures of differential DNA methylation in pediatric acute lymphoblastic leukemia.
Specimen part
View SamplesWe report ileal gene expression at diagnosis in a cohort of 210 treatment-naïve patients of pediatric Crohn''s disease and 35 non-IBD controls from the RISK study. After three years of follow-up after diagnosis, 27 of the CD patients progressed to complicated disease (B2 and/or B3). We aim to test whether Transcriptional Risk Scores helps to distinguish between patient subgroups, improving the predictive power gained from Genetic Risk Scores. Overall design: Ileal biopsies were obtained during diagnostic colonoscopies of children and adolescents (<17 years) who presented with symptoms of IBD. Non-IBD control label corresponds to those with suspected IBD, but without inflammation and normal endoscopic findings. Biopsies were stored at -80 degrees.
Transcriptional risk scores link GWAS to eQTLs and predict complications in Crohn's disease.
No sample metadata fields
View SamplesThe requirement of frozen tissues for microarray experiments limits the clinical usage of genome-wide expression profiling using microarray technology.
Robust gene expression signature from formalin-fixed paraffin-embedded samples predicts prognosis of non-small-cell lung cancer patients.
Sex, Specimen part, Race
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