Project description:<p>Gene expression is a biological process regulated at different molecular levels, including chromatin accessibility, transcription, and RNA maturation and transport. In addition, these regulatory mechanisms have strong links with cellular metabolism. Here we present a multi-omics dataset that captures different aspects of this multi-layered process in yeast. We obtained RNA-seq, metabolomics, and H4K12Ac ChIP-seq data for wild-type and mip6delta strains during a heat-shock time course. Mip6 is an RNA-binding protein that contributes to RNA export during environmental stress and is informative of the contribution of post-transcriptional regulation to control cellular adaptations to environmental changes. The experiment was performed in quadruplicate, and the different omics measurements were obtained from the same biological samples, which facilitates the integration and analysis of data using covariance-based methods. We validate our dataset by showing that ChIP-seq, RNA-seq and metabolomics signals recapitulate existing knowledge about the response of ribosomal genes and the contribution of trehalose metabolism to heat stress.</p>
Project description:Human cells identify invading pathogens and activate immune signaling pathways through a wide array of pattern recognition receptors, such as DNA sensors. The interferon-inducible protein 16 (IFI16) is a nuclear DNA sensor that recognizes double-stranded DNA from a number of viral sources, including genomes of nuclear-replicating viruses such as the prevalent human pathogen, herpes simplex virus 1 (HSV-1). Upon binding to the DNA genome of HSV-1, IFI16 both induces antiviral cytokine expression and suppresses virus gene expression. Here, we use a multi-omics approach of DNA sequencing techniques paired with targeted mass spectrometry to obtain an extensive view of the interaction between IFI16 and the HSV-1 genome, and how this binding affects the viral DNA structure and protein expression. Through ChIP-seq, we find that IFI16 binds to the HSV-1 genome in a sequence-independent manner while simultaneously exhibiting broad enrichment at two loci: UL30, the viral DNA polymerase gene, and US1-US7. ATAC-seq analysis reveals that these two regions are among the most accessible stretches of DNA on the genome, thereby facilitating IFI16 binding. Accessibility of the entire HSV-1 genome is elevated upon IFI16-KO, indicating that expression of IFI16 globally induces chromatinization of viral DNA, regardless of IFI16 enrichment. Deletion of IFI16 also results in a global increase in the expression of HSV-1 proteins, as measured by parallel reaction monitoring-mass spectrometry. Altogether, we demonstrate that IFI16 interacts with the HSV-1 genome in a sequence-independent manner, and this interaction coordinates epigenetic silencing of the viral genome, resulting in decreased protein expression and virus replication.
Project description:The key myeloid transcription factor (TF) CEBPA is frequently mutated in acute myeloid leukemia (AML), but the molecular ramifications of this leukemic driver mutation remain elusive. To investigate CEBPA mutant AML, we compared gene expression changes in human CEBPA mutant AML and in the corresponding CebpaLp30 mouse model, and identified a conserved cross-species transcriptional program. ChIP-seq revealed aberrantly activated enhancers, exclusively occupied by the leukemia-associated CEBPA-p30 isoform. One leukemic-enhancer upstream of Nt5e, encoding CD73, was physically and functionally linked to this conserved AML gene, and could be activated by CEBPA. Targeting of CD73-adenosine signaling increased AML survival in transplanted mice. Our data indicate a first-in-class link between a TF cancer driver mutation and a druggable, direct transcriptional target.
Project description:This model is from the article:
A regulatory role for repeated decoy transcription factor binding sites in target gene expression.
Lee TH, Maheshri N. Mol Syst Biol.
2012 Mar 27;8:576. 22453733
,
Abstract:
Tandem repeats of DNA that contain transcription factor (TF) binding sites could serve as decoys, competitively binding to TFs and affecting target gene expression. Using a synthetic system in budding yeast, we demonstrate that repeated decoy sites inhibit gene expression by sequestering a transcriptional activator and converting the graded dose-response of target promoters to a sharper, sigmoidal-like response. On the basis of both modeling and chromatin immunoprecipitation measurements, we attribute the altered response to TF binding decoy sites more tightly than promoter binding sites. Tight TF binding to arrays of contiguous repeated decoy sites only occurs when the arrays are mostly unoccupied. Finally, we show that the altered sigmoidal-like response can convert the graded response of a transcriptional positive-feedback loop to a bimodal response. Together, these results show how changing numbers of repeated TF binding sites lead to qualitative changes in behavior and raise new questions about the stability of TF/promoter binding.
Note:
This model corresponds to the basic model for gene expression in the presence of decoys, described in the paper.
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To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
Project description:Enhancers are fundamental to gene regulation. Post-translational modifications by the small ubiquitin-like modifiers (SUMO) modify chromatin regulation enzymes, including histone acetylases and deacetylases. However, it remains unclear whether SUMOylation regulates enhancer marks, acetylation at the 27th lysine residue of the histone H3 protein (H3K27Ac). We hypothesize that SUMOylation regulates H3K27Ac. To test this hypothesis, we performed genome-wide ChIP-seq analyses. We discovered that knockdown (KD) of the SUMO activating enzyme catalytic subunit UBA2 reduced H3K27Ac at most enhancers. Bioinformatic analysis revealed that TFAP2C-binding sites are enriched in enhancers whose H3K27Ac was reduced by UBA2 KD. ChIP-seq analysis in combination with molecular biological methods showed that TFAP2C binding to enhancers increased upon UBA2 KD or inhibition of SUMOylation by a small molecule SUMOylation inhibitor. However, this is not due to the SUMOylation of TFAP2C itself. Proteomics analysis of TFAP2C interactome on the chromatin identified histone deacetylation (HDAC) machinery. TFAP2C KD reduced HDAC binding to chromatin and increased H3K27Ac marks at enhancer regions, suggesting that TFAP2C is involved in recruiting HDAC. Taken together, our findings provide important insights into regulation of enhancer marks by SUMOylation.
Project description:In this study, we engineered a micro-well duct-on-chip platform to generate defined 3D aggregates from hiPSC-derived PPs and subsequently induce differentiation toward PDLOs. Time-resolved scRNA-seq combined with cleared immunofluorescence imaging provided a deep understanding of in vitro ductal cell type differentiation. By defining the emergent cell types at each stage of differentiation based on their gene expression profiles and organoid structures, we provide a precise cell-by-cell description of the in vitro differentiation trajectory. Transcriptional data of PDLOs were complemented by their proteome and secretome data, allowing the identification and validation of prognostic cancer marker. Thus, we show the applicability of hiPSC-derived PDLOs-on-chip for future ductal disease modeling.
Project description:We determined the effect of p53 activation on de novo protein synthesis using quantitative proteomics of newly synthesized proteins (pulsed stable isotope labeling with amino acids in cell culture, pSILAC) in combination with mRNA and non-coding RNA expression analyses by next generation sequencing (RNA-, miR-Seq) in the colorectal cancer (CRC) cell line SW480. Furthermore, genome-wide DNA binding of p53 was analyzed by chromatin-immunoprecipitation (ChIP-Seq). Thereby, we identified differentially regulated mRNAs (1258 up, 415 down), miRNAs (111 up, 95 down), lncRNAs (270 up, 123 down) and proteins (542 up, 569 down). Changes in mRNA and protein expression levels showed a positive correlation (r = 0.50, p < 0.0001). More transcriptionally induced genes displayed occupied p53 binding sites (4.3% mRNAs, 7.2% miRNAs, 6.3% lncRNAs, 5.9% proteins) than repressed genes (2.4% mRNAs, 3.2% miRNAs, 0.8% lncRNAs, 1.9% proteins), suggesting indirect mechanisms of repression. Around 50% of the downregulated proteins displayed seed-matching sequences of p53-induced miRNAs in the corresponding 3â??-UTRs. Moreover, proteins repressed by p53 significantly overlapped with those previously shown to be repressed by miR-34a. We confirmed upregulation of the novel direct p53 target genes LINC01021, MDFI, ST14 and miR-486 and showed that ectopic LINC01021 expression inhibited proliferation in SW480 cells. Furthermore, HMGB1, KLF12 and CIT mRNAs were confirmed as direct targets of the p53-induced miR-34a, miR-205 and miR-486-5p, respectively. In line with the loss of p53 function during tumor progression, elevated expression of HMGB1, KLF12 and CIT was detected in advanced stages of cancer. This study provides new insights and a comprehensive catalogue of p53-mediated regulations and p53 DNA binding in CRC cells.
Project description:The Nucleosome Remodeling and Deacetylase (NuRD) complex plays an important role in gene expression regulation, stem cell self-renewal, and lineage commitment. Yet little is known about the dynamics of NuRD during cellular differentiation. Here, we study these dynamics using genome-wide profiling and quantitative interaction proteomics in mouse embryonic stem cells (ESCs) and neural progenitor cells (NPCs). The genomic targets of NuRD are highly dynamic during differentiation, with most binding occurring at cell-type specific promoters and enhancers. We identify ZFP296 as a novel, ESC-specific NuRD interactor that also interacts with the SIN3A complex. ChIP-sequencing in Zfp296 knockout (KO) ESCs reveals decreased NuRD binding both genome-wide and at ZFP296 binding sites, although this has little effect on the transcriptome. Nevertheless, Zfp296 KO ESCs exhibit delayed induction of lineage-specific markers upon differentiation to embryoid bodies. In summary, we identify an ESC-specific NuRD interacting protein which regulates genome-wide NuRD binding and cellular differentiation.
Project description:Sequence-specific DNA-binding proteins including transcription factors (TFs) are key determinants of gene regulation and chromatin architecture. Formaldehyde cross-linking and sonication followed by Chromatin ImmunoPrecipitation (X-ChIP) and sequencing is widely used for genome-wide profiling of protein binding, but is limited by low resolution and poor specificity and sensitivity. We have implemented a simple genome-wide ChIP protocol that starts with micrococcal nuclease-digested uncross-linked chromatin followed by affinity purification and paired-end sequencing without size-selection. The resulting ORGANIC (Occupied Regions of Genomes from Affinity-purified Naturally Isolated Chromatin) profiles of the budding yeast TFs Abf1 and Reb1 achieved near-perfect accuracy, in contrast to other profiling methods, which were much less sensitive and specific. Unlike profiles produced using X-ChIP methods such as ChIP-exo, ORGANIC profiles are not biased toward identifying sites in accessible chromatin and do not require input normalization. We also demonstrate the high specificity of our method when applied to larger genomes by profiling Drosophila GAGA Factor and Pipsqueak. Taken together, these results suggest that ORGANIC profiling outperforms current X-ChIP methodologies for genome-wide profiling of TF binding sites. Chromatin immunoprecipitation of micrococcal nuclease-digested native chromatin followed by paired-end sequencing (Occupied Regions of Genomes from Affinity-purified Naturally Isolated Chromatin 'ORGANIC' profiling) of DNA-binding proteins Abf1 and Reb1 from S. cerevisiae and GAGA-binding factor (GAF) and Pipsqueak (Psq) from D. melanogaster S2 cells; and, Sono-seq (paired-end sequencing of formaldehyde cross-linked and sonicated chromatin) of yeast nuclei. Reb1 ORGANIC profiling was performed at three different salt (NaCl) concentrations (80, 150, and 600 mM) and Abf1 ORGANIC profiling was done at two different salt concentrations (80 and 600 mM) to achieve varying levels of stringency. GAF and Psq ORGANIC profiles were determined at 80 mM salt. Two replicates each of Reb1 and Abf1 600 mM ORGANIC experiments, mixed Drosophila S2 cell and S. cerevisiae nuclei Reb1 ORGANIC experiments, yeast Sono-seq, and GAF and Psq ORGANIC experiments were performed. Each S. cerevisiae and mixed S2 cell/yeast ORGANIC profiling experiment included separately sequenced input chromatin and ChIP samples. Total of 24 samples.