Transcription regulation involves enzyme-mediated changes in chromatin structure. Here, we describe a novel mode of histone crosstalk during gene silencing, in which histone H2A monoubiquitylation is coupled to the removal of histone H3 Lys 36 dimethylation (H3K36me2). This pathway was uncovered through the identification of dRING-associated factors (dRAF), a novel Polycomb group (PcG) silencing complex harboring the histone H2A ubiquitin ligase dRING, PSC and the F-box protein, and demethylase dKDM2. In vivo, dKDM2 shares many transcriptional targets with Polycomb and counteracts the histone methyltransferases TRX and ASH1. Importantly, cellular depletion and in vitro reconstitution assays revealed that dKDM2 not only mediates H3K36me2 demethylation but is also required for efficient H2A ubiquitylation by dRING/PSC. Thus, dRAF removes an active mark from histone H3 and adds a repressive one to H2A. These findings reveal coordinate trans-histone regulation by a PcG complex to mediate gene repression.
dKDM2 couples histone H2A ubiquitylation to histone H3 demethylation during Polycomb group silencing.
Cell line
View SamplesSTAT5 interacts with other factors to control transcription, and the mechanism of regulation is of interest as constitutive active STAT5 has been reported in malignancies. Here LSD1 and HDAC3 were identified as novel STAT5a interacting partners in pro-B cells. Characterization of STAT5a, LSD1 and HDAC3 target genes by ChIP-seq and RNA-seq revealed gene subsets regulated by independent or combined action of the factors and LSD1/HDAC3 to play dual role in their activation or repression. Genes bound by STAT5a alone or in combination with weakly associated LSD1 or HDAC3 were enriched for the canonical STAT5a dimer motif, and such binding induced activation or repression. Strong STAT5 binding was seen more frequently in intergenic regions, which might function as distal enhancer elements. Genes bound weakly by STAT5a and strongly by LSD1/HDAC3 present a STAT5a monomer like motif, and are differentially regulated based on their biological role, genomic binding localization and affinity. STAT5a binding in monomer like motifs was found with increased frequency in promoters, indicating a requirement for stabilization by additional factors, which might recruit LSD1/HDAC3. Our study describes an interaction network of STAT5a/LSD1/HDAC3 and a dual function of LSD1/HDAC3 on STAT5-dependent transcription, defined by protein-protein interactions, genomic binding positions-affinities and motifs. Overall design: Mouse pro-B Ba/F3 cells treated with lentiviral vectors expressing short-hairpins to knock-down various genes (STAT5a, STAT5b, LSD1 and HDAC3). All KDs were analysed versus cells treated with lentiviral construct expressing a No-Target short-hairpin at the same condition (either minus [IL3 deprivation for 6h] or plus [IL3 deprivation for 6h and IL3 stimulation for 30min]). Wild-type cells were also generated and compared between the two conditions. All samples contain biological replicates (3-5 depending on the sample).
The dual role of LSD1 and HDAC3 in STAT5-dependent transcription is determined by protein interactions, binding affinities, motifs and genomic positions.
Cell line, Treatment, Subject
View SamplesWe investigated the association between subgingival bacterial profiles and gene expression patterns in gingival tissues of patients with periodontitis.
Subgingival bacterial colonization profiles correlate with gingival tissue gene expression.
Specimen part
View SamplesWe examined gene expression signatures in healthy and diseased gingival tissues in 90 patients. Analysis of the gingival tissue transcriptome in states of periodontal health and disease may reveal novel insights of the pathobiology of periodontitis.
Transcriptomes in healthy and diseased gingival tissues.
Specimen part
View SamplesPeriodontal infections have been associated with systemic inflammation and risk for atherosclerosis and vascular disease. We investigated the effects of comprehensive periodontal therapy on gene expression of peripheral blood monocytes. Approximately 1/3 of the patients showed substantial changes in expression in genes relevant to innate immunity, apoptosis, and cell signaling. We concluded that periodontal therapy may alter monocytic gene expression in a manner consistent with a systemic anti-inflammatory effect.
Periodontal therapy alters gene expression of peripheral blood monocytes.
Specimen part, Time
View SamplesWe have ablated TAF10 in the erythroid compartment only by crossing the TAF10lox mice with the EpoR-Cre mice and we have studied the development of the erythroid cells in vivo. TAF10 ablation led to embryonic death at E13.5 while at E12.5 there was a clear developmental defect which was reflected in the transcriptional profile of the fetal liver cells. Gata1-target genes were mostly affected and were responsible for the lethal phenotype. Overall design: mRNA from E12.5 fetal livers of TAF10lox/KO:EpoR-Cre+/- (TAF10KO) mice, TAF10HET and WT mice was profiled by NGS (Illumina).
TAF10 Interacts with the GATA1 Transcription Factor and Controls Mouse Erythropoiesis.
No sample metadata fields
View SamplesSp1 and Sp3 belong to the Specificity proteins (Sp)/Krüppel-like transcription factor family. They are closely related, ubiquitously expressed and recognize G-rich DNA motifs. They are thought to regulate generic processes such as cell cycle and growth control, metabolic pathways and apoptosis. Ablation of Sp1 or Sp3 in mice is lethal, and combined haploinsufficiency results in hematopoietic defects during the fetal stages. Here, we show that in adult mice conditional ablation of either Sp1 or Sp3 has minimal impact on hematopoiesis, while the simultaneous loss of Sp1 and Sp3 results in severe macrothrombocytopenia and platelet dysfunction. We employed flow cytometry, cell culture and electron microscopy and show that although megakaryocyte numbers are normal in bone marrow and spleen, they display a less compact demarcation membrane system and a striking inability to form proplatelets. Through megakaryocyte transcriptomics and platelet proteomics we identified several cytoskeleton-related proteins and downstream effector kinases, including Mylk, that were downregulated upon Sp1/Sp3 depletion, providing an explanation for the observed defects in megakaryopoiesis. We show that Mylk is required for proplatelet formation and stabilization and for ITAM-receptor mediated platelet aggregation. Our data highlights the specific vs generic role of these ubiquitous transcription factors in the highly specialized megakaryocytic lineage. Overall design: Megakaryocyte mRNA profiles of Sp1fl/fl::Sp3fl/fl (WTlox) and Pf4-Cre::Sp1fl/fl::Sp3fl/fl (dKO) mice were generated by deep sequencing, in triplicate.
Sp1/Sp3 transcription factors regulate hallmarks of megakaryocyte maturation and platelet formation and function.
No sample metadata fields
View SamplesBackground: Venous hypertension is often present in advanced and in acute decompensated heart failure (HF). However, it is unclear whether high intravenous pressure can cause alterations in homeostasis by promoting inflammation and endothelial cell (EC) activation. We used an experimental model of acute, local venous hypertension to study the changes in circulating inflammatory mediators and EC phenotype that occur in response to biomechanical stress. Methods and Results: Twenty-four healthy subjects (14 men, age 352 years) were studied. Venous arm pressure was increased to ~30 mmHg above baseline level by inflating a tourniquet cuff around the dominant arm (test arm). Blood and endothelial cells (ECs) were sampled from test and control arm (lacking an inflated cuff) before and after 75 minutes of venous hypertension, using angiocatheters and endovascular wires. Magnetic beads coated with EC specific antibodies were used for EC separation; amplified mRNA was analyzed by Affymetrix HG-U133 2.0 Microarray. Plasma endothelin-1 (ET-1), interleukin-6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1) and chemokine (C-X-C motif) ligand 2 (CXCL2) were significantly increased in the congested arm. 5,332 probe sets were differentially expressed in venous ECs before vs. after testing. Among the 143 probe sets that exhibited a significant absolute fold change >2, we identified several inflammatory mediators including ET-1, VCAM-1, and CXCL2. Conclusions: Acute experimental venous hypertension is sufficient to cause local increase in circulating inflammatory mediators and to activate venous ECs in healthy human subjects. Additional work is needed to determine the effect of venous hypertension in patients with established HF.
Peripheral venous congestion causes inflammation, neurohormonal, and endothelial cell activation.
Specimen part, Treatment, Subject
View SamplesWe performed microarray analysis to investigate the gene expression profile changes induced by Hmg20b knock down in I/11 cells.
The DNA binding factor Hmg20b is a repressor of erythroid differentiation.
Specimen part
View SamplesThe molecular mechanisms of neurogenic fate determination are of particular importance in light of the need to regenerate neurons. However the molecular logic of neurogenic fate determination is still ill understood, even though some key transcription factors have been implicated. Here we describe how one of these, the transcription factor Pax6, regulates adult neurogenesis by initiating a cross-regulatory network of 3 transcription factors executing neuronal fate and regulating genes required for neuronal differentiation. This network is initiated and driven to sufficiently high expression levels by the transcription factor Pax6 in close interaction with Brg1-containing SWI/SNF chromatin remodeling factors.
The BAF complex interacts with Pax6 in adult neural progenitors to establish a neurogenic cross-regulatory transcriptional network.
Sex, Age, Specimen part
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