We have observed that follicular B cells from mice with a hypomorphic mutation (IkL/L) in the Ikzf1 gene (which encodes the Ikaros transcription factor) exhibit an increased proliferative response to anti-IgM stimulation (Kirstetter et al, Eur J Immunol, 32:720-30, 2002). We asked if Ikaros controls the transcriptional response that unfolds after activation, or if differences in the transcriptional landscape of resting B cells could explain the altered response. To this end, we have determined the transcriptome of unstimulated WT and IkL/L follicular B cells, as well as that of cells stimulated for 3h and 12h with anti-IgM. Samples from 2 independent experients were analyzed.
Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways.
Age, Specimen part
View SamplesThe Drosha-DGCR8 complex (Microprocessor) is required for microRNA (miRNA) biogenesis. DGCR8 contains two double-stranded RNA binding motifs that recognize the RNA substrate, whereas Drosha functions as the endonuclease. We have used high-throughput sequencing of RNAs isolated by crosslinking immunoprecipitation (HITS-CLIP) to identify endogenous RNA targets of DGCR8 in mammalian cells. Unexpectedly, miRNAs were not the most abundant targets. DGCR8-bound RNAs comprised several hundred mRNAs as well as snoRNAs and long non-coding RNAs. We found that DGCR8 together with Drosha controls the abundance of several mRNAs, as well as long non-coding RNAs, such as MALAT-1. By contrast, the DGCR8-mediated cleavage of snoRNAs is independent of Drosha, suggesting the involvement of DGCR8 in cellular complexes with other endonucleases. Interestingly, binding of DGCR8 to cassette exons, acts as a novel mechanism to regulate the relative abundance of alternatively spliced isoforms. Collectively, these data provide new insights in the complex role of DGCR8 in controlling the fate of several classes of RNAs. Overall design: Comparison of RNAs associated to both endogenous (D8) and overexpressed (T7) DGCR8 in HEK293T cells
Drosha regulates gene expression independently of RNA cleavage function.
Cell line, Subject
View SamplesThe experiment aimed at determining the genes that are under the control of the Ikaros transcription factor in mouse splenic B1 and B2 B lymphocyte subsets. To this aim, we used Ikf/f R26-CreERT2+ (Cre+) or Ikf/f R26-CreERT2- (Cre-) mice, which correspond to mice with floxed null alleles for Ikzf1 (Heizmann et al., JEM 210:2823-32, 2013) that were crossed with the R26-CreERT2 mice, which harbor a knock-in of the cDNA encoding the tamoxifen (TAM) inducible CreERT2 recombinase in the Rosa26 gene (Badea et al, J. Neurosci 23:2314-22, 2003). 6-8 week-old mice were injected daily with TAM for 3d (50mg/kg). Mice were sacrificed 10d after the first injection, and splenic B1 and B2 B cell populations sorted by flow cytometry.
Ikaros Is a Negative Regulator of B1 Cell Development and Function.
Sex, Specimen part
View SamplesMyocardial infarction (MI) often results in left ventricular (LV) remodeling followed by heart failure (HF). It is of great clinical importance to understand the molecular mechanisms that trigger transition from compensated LV injury to HF and to identify relevant diagnostic biomarkers. In this study, we performed transcriptional profiling of LVs in rats with a wide range of experimentally induced infarct sizes and of peripheral blood mononuclear cells (PBMCs) in animals that developed HF.
Transcriptional profiling of left ventricle and peripheral blood mononuclear cells in a rat model of postinfarction heart failure.
Specimen part
View SamplesExpression data from antigen-experienced Nfat1+/+ and Nfat1-/- CD4+ T cells following 21 days of Plasmodium yoelii 17XNL infection.
The Transcription Factor NFAT1 Participates in the Induction of CD4<sup>+</sup> T Cell Functional Exhaustion during Plasmodium yoelii Infection.
Sex, Specimen part
View SamplesPromoter recognition by bacterial RNA polymerase is mediated by subunits, which assemble transiently to RNA polymerase core enzyme (E) during transcription initiation. subunits drive transcription of specific sets of genes by allowing RNA polymerase to interact with different promoter sequences. However, 70, the housekeeping subunit, and S, an alternative subunit mainly active during slow growth and in response to cellular stresses, appear to recognize almost identical promoter sequences, raising the question of how promoter selectivity is achieved in the bacterial cell. To identify sequence determinants for selective promoter recognition, we performed a run-off/microarray experiment (ROMA): in vitro transcription experiments were carried out with RNA polymerase saturated either with 70 (E70) or with S (ES) using the whole Escherichia coli genome as DNA template, and transcript levels were determined by microarray analysis. We found that several genes associated with bacterial growth (e.g., ribosomal operons) were transcribed more efficiently by E70. In contrast, ES transcribed preferentially genes involved in stress responses, secondary metabolism, as well as regulatory RNAs and intergenic regions with yet unknown function. Genes preferentially recognized in vitro by ES showed reduced expression in ES -deficient mutant strain of E. coli. Sequence comparison of E70- versus ES dependent promoters confirms that the presence of a -35 sequence and the relative location of UP elements affect promoter interaction with either form of RNA polymerase, and suggests that a G/C bias in the -2/+1 nucleotides would favour efficient promoter recognition by E70.
In vitro transcription profiling of the σS subunit of bacterial RNA polymerase: re-definition of the σS regulon and identification of σS-specific promoter sequence elements.
Disease
View SamplesWe compare the CD4+ T cell transcriptome between obese and normal-weight children with asthma to identify molecules/pathways differentially expressed in obese asthmatic CD4+ T cells Overall design: CD4+ T cell transcriptome generated using Directional RNA-Seq library preparatio; A=Normal-weight, B=obese
CDC42-related genes are upregulated in helper T cells from obese asthmatic children.
Sex, Age, Specimen part, Disease stage, Race, Subject
View SamplesIt is becoming increasingly apparent that Staphylococcus aureus are able to survive engulfment by macrophages, and that the intracellular environment of these cells, which is essential to innate host defenses against invading microorganisms, may in fact provide a refuge for staphylococcal survival and dissemination. Based on this, we postulated that S. aureus might induce cytoprotective mechanisms by changing gene expression profiles inside macrophages similar to obligate intracellular pathogens, such as Mycobacterium tuberculosis.
Phagocytosis of Staphylococcus aureus by macrophages exerts cytoprotective effects manifested by the upregulation of antiapoptotic factors.
No sample metadata fields
View SamplesUsing an siRNA screen we identify a role for GPR65 in the defense against intracellular pathogens. Epithelial cells and macrophages lacking GPR65 exhibited impaired clearance of intracellular bacteria as well as an accumulation of aberrant phagosomes and lysosomes. Transcriptional profiling revealed changes in genes associated with lysosomal function. Overall design: Bone marrow-derived macrophages from WT or Gpr65-/- mice were harvested for RNA analysis.
Genetic Coding Variant in GPR65 Alters Lysosomal pH and Links Lysosomal Dysfunction with Colitis Risk.
No sample metadata fields
View SamplesWe identify sites of combinatorial control by performing high throughput ChIP experiments on p300, CREB-binding protein (CBP), the deacetylase SIRT1 and on multiple DNA-binding transcription factors in three different tissues. We present a quantitative model of transcriptional regulation that reveals the contribution of each binding site to tissue-specific gene expression in several mouse cell types. Binding to both evolutionarily conserved and non-conserved sequences is found to contribute significantly to transcriptional regulation. We demonstrate that binding location strongly predicts the expression level of nearby genes.
A quantitative model of transcriptional regulation reveals the influence of binding location on expression.
Specimen part
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