This SuperSeries is composed of the SubSeries listed below.
Dissecting the retinoid-induced differentiation of F9 embryonal stem cells by integrative genomics.
Cell line, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reconstruction of gene regulatory networks reveals chromatin remodelers and key transcription factors in tumorigenesis.
Specimen part, Cell line
View SamplesRetinoic acid (RA) triggers physiological processes by activating heterodimeric transcription factors comprising retinoic acid (RARa,b,g) and retinoid X (RXRa,b,g) receptors. How a single signal induces highly complex temporally controlled networks that ultimately orchestrate physiological processes is unclear. Using an RA-inducible differentiation model we defined the temporal changes in the genome-wide binding patterns of RARg and RXRa and correlated them with transcription regulation. Unexpectedly, both receptors displayed a highly dynamic binding, with different RXRa heterodimers targeting identical loci. Comparison of RARg and RXRa co-binding at RA-regulated genes identified putative RXRa-RARg target genes that were validated with subtype-selective agonists. Gene regulatory decisions during differentiation were inferred from transcription factor target gene information and temporal gene expression. This analysis revealed 6 distinct co-expression paths of which RXRa-RARg is associated with transcription activation, while Sox2 and Egr1 were predicted to regulate repression. Finally, RXRa-RARg regulatory networks were reconstructed through integration of functional co-citations. Our analysis provides a dynamic view of RA signalling during cell differentiation, reveals RA heterodimer dynamics and promiscuity, and predicts decisions that diversify the RA signal into distinct gene-regulatory programs.
Dissecting the retinoid-induced differentiation of F9 embryonal stem cells by integrative genomics.
Cell line, Time
View SamplesAlthough recent evidence suggests that overlapping sense/antisense transcription is a common feature in higher eukaryotes, the possibility that overlapping transcripts could interact to each other and bear a specific biological function has not been explored. Here we show that a plethora of sense/antisense transcript pairs are co-expressed from 8q24.21 within the same cell and acquire a stable double-stranded RNA conformation. Interestingly, these molecules display predominantly nuclear localization and establish specific interactions with nuclear components. A detailed characterization of a particular sense/antisense pair (ndsRNA-2a) revealed that this molecule displays differential localization throughout the cell cycle, interacts with RCC1 and RAN and through the latter with the mitotic RANGAP1-SUMO1/RANBP2 complex. Notably, an increased number of bi/multi-nucleated cells and chromatin bridges were observed upon ndsRNA-2a overexpression, whereas strand-specific ndsRNA-2a knockdown leads to mitotic catastrophe and cell death. This suggests a functional role of ndsRNA-2a in cell cycle progression that critically requires its double stranded nature. Finally, the identification of hundreds of sense/antisense transcripts pairs harboring ndsRNA profile signatures and their regulation by cellular cues suggests that ndsRNAs constitute a novel class of regulatory molecules that are likely to be involved in a plethora of biological processes. Overall design: PLB985 long (3x datasets) and small (3x datasets) strand specific RNA-Seq for captured RNAs. Global PLB985 for long (2x datasets) and small RNAs (2x datasets). Global libraries for EtOH (vehicle) treated (1x dataset) or retinoic acid induced differentiated PLB985 cells (1x dataset).
Human cells contain natural double-stranded RNAs with potential regulatory functions.
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View SamplesSenescent cells secrete a plethora of factors with potent paracrine signaling capacity. Strikingly, senescence, which acts as a defense against cell transformation, exerts pro-tumorigenic activities through its secretome by promoting numerous tumor-specific features, such as cellular proliferation, epithelial-mesenchymal transition and invasiveness. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has the unique activity of activating cell death exclusively in tumor cells. Given that the senescence-associated secretome supports cell transformation, we asked whether factor(s) of this secretome would establish a program required for the acquisition of TRAIL sensitivity. We found that conditioned media from several types of senescent cells (CMS) efficiently sensitized pre-transformed cells to TRAIL, while the same was not observed with normal or immortalized cells. Dynamic transcription profiling analysis of CMS-exposed pre-transformed cells revealed paracrine autoregulatory loop of senescence-associated secretome factors and a dominant role of CMS-induced MYC. Sensitization to TRAIL coincided with MYC upregulation and massive changes in gene regulation. CMS-induced MYC silenced its target gene CFLAR, encoding the apoptosis inhibitor FLIPL, thus leading to the acquisition of TRAIL sensitivity. Altogether, our results reveal that senescent cell-secreted factors exert a TRAIL sensitizing effect on pre-transformed cells by modulating the expression of MYC and CFLAR. Notably, CMS dose-dependent sensitization to TRAIL was observed with TRAIL-insensitive cancer cells and confirmed in co-culture experiments. Dissection and characterization of TRAIL-sensitizing CMS factors and the associated signaling pathway(s) may provide a mechanistic insight in the acquisition of TRAIL sensitivity and lead to novel concepts for the apoptogenic therapy of pre-malignant and TRAIL-resistant tumors.
Senescence-secreted factors activate Myc and sensitize pretransformed cells to TRAIL-induced apoptosis.
Cell line, Treatment, Time
View SamplesThe mechanistic links between transcription factors and the epigenetic landscape, which coordinate the deregulation of gene networks during cell transformation are largely unknown. We used an isogenic model of stepwise tumorigenic transformation of human primary cells to monitor the progressive deregulation of gene networks upon immortalization and oncogene-induced transformation. By combining transcriptome and epigenome data for each step during transformation and by integrating transcription factor (TF) - target gene associations, we identified 142 Tfs and 24 chromatin remodelers/modifiers (CRMs), which are preferentially associated with specific co-expression paths that originate from deregulated gene programming during tumorigenesis. These Tfs are involved in the regulation of divers processes, including cell differentiation, immune response and establishment/modification of the epigenome. Unexpectedly, the analysis of chromatin state dynamics revealed patterns that distinguish groups of genes, which are not only co-regulated but also functionally related. Further decortication of TF targets enabled us to define potential key regulators of cell transformation, which are engaged in RNA metabolism and chromatin remodelling. Our study suggests a direct implication of CRMs in oncogene-induced tumorigenesis and identifies new CRMs involved in this process. This is the first comprehensive view of gene regulatory networks that are altered during the process of stepwise human cellular tumorigenesis in a virtually isogenic system.
Reconstruction of gene regulatory networks reveals chromatin remodelers and key transcription factors in tumorigenesis.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reconstructed cell fate-regulatory programs in stem cells reveal hierarchies and key factors of neurogenesis.
Specimen part, Time
View SamplesWe have integrated dynamic RXRa binding, chromatin accessibility and promoter epigenetic status with the transcriptional activity inferred from RNA polymerase II mapping and transcription profiling. This demonstrated a temporal organization structure, in which early events are preferentially enriched for common GRNs, while cell fate specification is reflected by the activation of late programs in a cell-type specific manner. Furthermore, significant differences in cell lines' promoter status of genes associated with cell-line specific programs were inferred. Finally, a variety of transcription factors (TFs) playing a direct role in the signal transduction cascade downstream of the RXR/RAR initiated wiring were identified, several of them commonly regulated in both model systems, but in addition cell-type specific TF drivers were also identified.
Reconstructed cell fate-regulatory programs in stem cells reveal hierarchies and key factors of neurogenesis.
Specimen part, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Methylation specifies distinct estrogen-induced binding site repertoires of CBP to chromatin.
Cell line, Treatment, Time
View SamplesMultiple signaling pathways ultimately modulate the epigenetic information embedded in the chromatin of gene promoters by recruiting epigenetic enzymes. We found that, in estrogen-regulated gene programming, the acetyltransferase CREB-binding protein (CBP) is specifically and exclusively methylated by the coactivator-associated arginine methyltransferase (CARM1) in vivo. CARM1-dependent CBP methylation and p160 coactivators were required for estrogen-induced recruitment to chromatin targets. Notably, methylation increased the histone acetyltransferase (HAT) activity of CBP and stimulated its autoacetylation. Comparative genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) studies revealed a variety of patterns by which p160, CBP, and methyl-CBP (meCBP) are recruited (or not) by estrogen to chromatin targets. Moreover, significant target gene-specific variation in the recruitment of (1) the p160 RAC3 protein, (2) the fraction of a given meCBP species within the total CBP, and (3) the relative recruitment of different meCBP species suggests the existence of a target gene-specific fingerprint for coregulator recruitment. Crossing ChIP-seq and transcriptomics profiles revealed the existence of meCBP hubs within the network of estrogen-regulated genes. Together, our data provide evidence for an unprecedented mechanism by which CARM1-dependent CBP methylation results in gene-selective association of estrogen-recruited meCBP species with different HAT activities and specifies distinct target gene hubs, thus diversifying estrogen receptor programming.
Methylation specifies distinct estrogen-induced binding site repertoires of CBP to chromatin.
Cell line, Treatment, Time
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