This SuperSeries is composed of the SubSeries listed below.
Yin Yang 1 extends the Myc-related transcription factors network in embryonic stem cells.
Specimen part
View SamplesWe have determined the global gene expression upon loss of function of the Yy1 transcription factor in mouse embryonic stem cells
Yin Yang 1 extends the Myc-related transcription factors network in embryonic stem cells.
Specimen part
View SamplesThe 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.
Tet proteins connect the O-linked N-acetylglucosamine transferase Ogt to chromatin in embryonic stem cells.
Specimen part
View SamplesO-linked N-acetylglucosamine (O-GlcNAc ) transferase (OGT) activity is essential for embryonic stem (ES) cell viability and mouse development. OGT is present in both cytoplasm and nucleus of different cell types and mediates serine or threonine glycosylation. The Ogt gene locus resides on the X-chromosome and its activity is required for the viability of male ES cells. Using Ogt conditional knock out (KO) ES cells it was shown the failure of establishing stable KO ES clones further suggesting that Ogt activity is required for ES cell self-renewal and pluripotency. For understanding these changes, we performed global gene expression upon silencing of Ogt mediated by esiRNA in mouse Embryonic Stem Cells.
Tet proteins connect the O-linked N-acetylglucosamine transferase Ogt to chromatin in embryonic stem cells.
Specimen part
View SamplesTranscription factor (TF)-induced reprogramming of somatic cells into induced pluripotent stem cells (iPSC) is associated with genome-wide changes in chromatin modifications. Polycomb-mediated histone H3 lysine-27 trimethylation (H3K27me3) has been proposed as a defining mark that distinguishes the somatic from the iPSC epigenome. Here, we dissected the functional role of H3K27me3 in TF-induced reprogramming through the inactivation of the H3K27 methylase EZH2 at the onset of reprogramming. Our results demonstrate that surprisingly the establishment of functional iPSC proceeds despite global loss of H3K27me3. iPSC lacking EZH2 efficiently silenced the somatic transcriptome and differentiated into tissues derived from the three germ layers. Remarkably, the genome-wide analysis of H3K27me3 in Ezh2 mutant iPSC cells revealed the retention of this mark on a highly selected group of Polycomb targets enriched for developmental regulators controlling the expression of lineage specific genes. Erasure of H3K27me3 from these targets led to a striking impairment in TF-induced reprogramming. These results indicate that PRC2-mediated H3K27 trimethylation is required on a highly selective core of Polycomb targets whose repression enables TF-dependent cell reprogramming.
Cell reprogramming requires silencing of a core subset of polycomb targets.
Specimen part
View SamplesWe characterize histone crotonylation in intestinal epithelium-derived cells through Mass spectrometry, ChIp-Seq and RNA-Seq approaches and show that this modification is removed by class I histone deacetylases, HDAC1, 2 and 3. Overall design: RNA-Seq profile from mouse colon epithelium. ChIP-Seq experiments for H3K18crotonylation and H3K4me3 on mouse colon epithelium. ChIP-Seq experiments for H3K18 crotonylation and H3K18 acetylation on HCT116 cell line treated or not with the HDAC inhibitor MS275 (5 µM) for 18h. All the experiments were performed in triplicate.
Microbiota derived short chain fatty acids promote histone crotonylation in the colon through histone deacetylases.
No sample metadata fields
View SamplesEstrogen receptor positive (ER+) breast cancers that develop resistance to therapies that target the ER are the most common cause of breast cancer death. Beyond mutations in ER, which occur in 25-30% of patients treated with aromatase inhibitors (AIs), our understanding of clinical mechanisms of resistance to ER-directed therapies remains incomplete. We identified activating HER2 mutations in metastatic biopsies from eight patients with ER+ metastatic breast cancer who had developed resistance to ER-directed agents, including AIs, tamoxifen, and fulvestrant. Examination of treatment-naïve primary tumors in five patients revealed no evidence of pre-existing mutations in four of five patients, suggesting that these mutations were acquired under the selective pressure of ER-directed therapy. These mutations were mutually exclusive with ER mutations, suggesting a distinct mechanism of acquired resistance to ER-directed therapies. In vitro analysis confirmed that these mutations conferred estrogen independence. In addition, and in contrast to ER mutations, these mutations resulted in resistance to tamoxifen, fulvestrant, and the CDK4/6 inhibitor palbociclib. Resistance was overcome by combining ER-directed therapy with the irreversible HER2 kinase inhibitor neratinib, highlighting an effective treatment strategy in these patients. Overall design: Examination of the transcriptional output (mRNA) of the HER2 activating mutations compared with controls under various drugs. Specifically, we expressed the activating mutations S653C, L755S, V777L, and L869R in ER+/HER2- breast cancer cell line (T47D), and controls (GFP, wild-type HER2, kinase-dead HER2, and ESR1 Y537S). Cell were then treated with DMSO, 1µM fulvestrant, 1µM neratinib, 10µM palbociclib, 1µM fulvestrant + 1µM neratinib, or 1µM fulvestrant + 10µM palbociclib for 24 hours. All experimental conditions were done in 6 replicates, sequenced in 3 replicates
Acquired HER2 mutations in ER<sup>+</sup> metastatic breast cancer confer resistance to estrogen receptor-directed therapies.
No sample metadata fields
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