The activity of enhancers and promoters fine-tunes the transcriptional program of mammalian cells through the recruitment and interplay between cell type-specific and ubiquitous transcription factors. Despite their key role in modulating transcription, the identification of enhancers is challenged by their limited sequence conservation and highly variable distance from target genes. Although enhancers are characterised by the strong enrichment of mono-methylation at lysine 4 of histone H3, mirrored by low tri-methylation at the same residue, a comprehensive list of enhancers-associated histone post-translational modifications (PTMs) is still lacking. We undertook a proteomics investigation, based on chromatin immunoprecipitation combined with mass spectrometry (MS), to identify histone marks specifically associated to cis-regulatory elements in macrophages, focusing on enhancers. We also profiled their plasticity during the transcriptional activation induced by an inflammatory stimulus. The proteomic analysis suggested novel PTM associations, which were validated by analysis of ChIP- and RNA-seq data, whose intersection revealed the existence of novel sub-populations of enhancers marked by specific signatures: the dual mark H3K4me1/K36me2 labels transcription at enhancers, whereas H3K4me1/K36me3 and H3K4me1/K79me2 tag distinct intronic enhancers. While demonstrating that analyzing restricted genomic regions can disclose the combinatorial language of histone modifications, this study highlights the potential of MS-based proteomics in addressing fundamental questions in epigenetics. Overall design: Total RNA was extracted from 5x10^6 untreated RAW 264.7 cells using RNAeasy kit (Qiagen). Libraries were then prepared using TruSeq RNA sample preparation Kit (Illumina) after depleting ribosomal RNA
Chromatin proteomics reveals novel combinatorial histone modification signatures that mark distinct subpopulations of macrophage enhancers.
Specimen part, Cell line, Treatment, Subject
View SamplesThe enzymes of the poly-ADP-ribose polymerase (PARP) super-family control many relevant cellular processes, but a precise understanding of their activities in different physiological or disease contexts is largely incomplete. We found that transcription of several PARP genes was dynamically regulated upon macrophage activation by several inflammatory stimuli. Specifically, PARP14 was strongly induced by endotoxin stimulation and translocated to the nucleus in stimulated cells. Quantitative mass spectrometry analysis showed that PARP14 bound to a group of interferon-stimulated gene (ISG)-encoded proteins, most with an unknown function, and it was required for their nuclear accumulation. Moreover, PARP14 depletion attenuated transcription of primary antiviral response genes regulated by the transcription factor IRF3, including Ifnb1, thus reducing IFNß production and activation of ISGs involved in the secondary antiviral response. Overall, these data hint at a role of PARP14 in the control of antimicrobial responses and specifically in nuclear activities of a subgroup of ISG-encoded proteins. Overall design: mRNA sequencing of differentially expressed genes in PARP14 WT and KO RAW 264.7 cells, upon: no treatment, LPS, Jak inhibitor or LPS plus Jak inhibitor treatment.
PARP14 Controls the Nuclear Accumulation of a Subset of Type I IFN-Inducible Proteins.
Specimen part, Cell line, Treatment, Subject
View SamplesThe enzymes of the poly-ADP-ribose polymerase (PARP) super-family control many relevant cellular processes, but a precise understanding of their activities in different physiological or disease contexts is largely incomplete. We found that transcription of several PARP genes was dynamically regulated upon macrophage activation by several inflammatory stimuli. Specifically, PARP14 was strongly induced by endotoxin stimulation and translocated to the nucleus in stimulated cells. Quantitative mass spectrometry analysis showed that PARP14 bound to a group of interferon-stimulated gene (ISG)-encoded proteins, most with an unknown function, and it was required for their nuclear accumulation. Moreover, PARP14 depletion attenuated transcription of primary antiviral response genes regulated by the transcription factor IRF3, including Ifnb1, thus reducing IFNß production and activation of ISGs involved in the secondary antiviral response. Overall, these data hint at a role of PARP14 in the control of antimicrobial responses and specifically in nuclear activities of a subgroup of ISG-encoded proteins. Overall design: mRNA sequencing of differentially expressed genes in PARP14 WT RAW 264.7 cells, with or without LPS treatment
PARP14 Controls the Nuclear Accumulation of a Subset of Type I IFN-Inducible Proteins.
Specimen part, Cell line, Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reduced chromatin binding of MYC is a key effect of HDAC inhibition in MYC amplified medulloblastoma.
Specimen part, Treatment
View SamplesMYC is a driver oncogene in many cancers. Inhibition of MYC promises high therapeutic potential, but specific MYC inhibitors remain unavailable for clinical use. Previous studies suggest that MYC amplified Medulloblastoma cells are vulnerable to HDAC inhibition. Using co-immunoprecipitation, mass spectrometry and ChIP-sequencing we show that HDAC2 is a cofactor of MYC in MYC amplified primary medulloblastoma and cell lines. The MYC-HDAC2 complex is bound to genes defining the MYC-dependent transcriptional profile. Class I HDAC inhibition leads to stabilization and reduced DNA binding of MYC protein inducing a down-regulation of MYC activated genes (MAGs) and up-regulation of MYC repressed genes (MRGs). MAGs and MRGs are characterized by opposing biological functions and distinct E-box distribution. We conclude that MYC and HDAC2 (class I) are localized in a complex in MYC amplified medulloblastoma and drive a MYC-specific transcriptional program, which is reversed by the class I HDAC inhibitor entinostat. Thus, the development of HDAC inhibitors for treatment of MYC amplified medulloblastoma should include HDAC2 in its profile in order to directly target MYC´s trans-activating and trans-repressing function.
Reduced chromatin binding of MYC is a key effect of HDAC inhibition in MYC amplified medulloblastoma.
Specimen part, Treatment
View SamplesEwing's Sarcoma cell lines were made resistant to different IGF-1R drugs to investigate mechanisms and pathways modulated by the resistance.
Identification of common and distinctive mechanisms of resistance to different anti-IGF-IR agents in Ewing's sarcoma.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Epigenetic chromatin states uniquely define the developmental plasticity of murine hematopoietic stem cells.
Specimen part
View SamplesAn investigation of the global gene expression signatures of murine hematopoietic stem cell differentiation during steady state hematopoiesis.
Epigenetic chromatin states uniquely define the developmental plasticity of murine hematopoietic stem cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dominant negative PPARγ promotes atherosclerosis, vascular dysfunction, and hypertension through distinct effects in endothelium and vascular muscle.
Specimen part
View SamplesPharmacological activation of the transcription factor PPAR gamma lowers blood pressure and improves glucose tolerance in humans. In contrast, naturally occurring mutations (e.g., P467L, V290M) in the ligand binding domain of PPAR gamma in humans leads to severe insulin resistance and early-onset hypertension. Experimental evidence, including whole genome expression profiling, suggests that these mutant versions of PPAR gamma act in a dominant negative manner. Because PPAR gamma is expressed in a variety of cell types and tissues, we generated a transgenic mouse model (SP467L) specifically targeting dominant negative PPAR gamma to the vascular smooth muscle cells in order to determine the action of PPAR gamma in the blood vessel independent of its systemic metabolic actions. In the data set provided herein, we examined the gene expression profile in thoracic aorta from SP467L mice and their control littermates using the Affymetrix Mouse Genome 430 2.0 array.
Dominant negative PPARγ promotes atherosclerosis, vascular dysfunction, and hypertension through distinct effects in endothelium and vascular muscle.
Specimen part
View Samples