Small RNA-seq on MCF10A, HCT116 and HCT116p53-/- cell lines after induction of DNA damage (5 Gy Irradiation). Overall design: Small RNA-seq on MCF10A, HCT116 and HCT116p53-/- at 4 and 24 hours after induction of DNA damage (5 Gy Irradiation), done in duplicate with respective control (0 hour) using illumina Genome Analyzer IIx
p53 shapes genome-wide and cell type-specific changes in microRNA expression during the human DNA damage response.
Cell line, Treatment, Subject, TimeView Samples
Cancer cells have abnormal gene expression profiles, however, the transcription factors and the architecture of the regulatory network that drive cancer specific gene expression is often not known. Here we studied a model of Ras-driven invasive tumorigenesis in Drosophila epithelial tissues and combined in vivo genetics with high-throughput sequencing and computational modeling to decipher the regulatory logic of tumor cells. Surprisingly, we discovered that the bulk of the tumor specific gene expression is driven by an ectopic network of a few transcription factors that are overexpressed and/or hyperactivated in tumor cells. These factors are Stat, AP-1, the bHLH proteins Myc and AP-4, the nuclear hormone receptor Ftz-f1, the nuclear receptor coactivator Taiman/AIB1, and Mef2. Notably, many of these transcription factors are also hyperactivated in human tumors. Bioinformatics analysis predicted that these factors directly regulate the majority of the tumor specific gene expression, that they are interconnected by extensive cross-regulation, and that they show a high degree of co-regulation of target genes. Indeed, the factors of this network were required in multiple epithelia for tumor growth and invasiveness and knock-down of individual factors caused a reversion of the tumor specific expression profile, but had no observable effect on normal tissues. We further found that the Hippo pathway effector Yki/Sd was strongly activated in tumor cells and initiated cellular reprogramming by activating several transcription factors of this network. Thus, modeling regulatory networks identified an ectopic yet highly ordered network of master regulators that control tumor cell specific gene expression. Overall design: RNA-seq gene expression profiling across Drosophila 3rd instar larval wild type wing discs and genetic perturbations of wts.
An Ectopic Network of Transcription Factors Regulated by Hippo Signaling Drives Growth and Invasion of a Malignant Tumor Model.
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The lower glucose-responsiveness of neonatal beta cells is generally considered a sign of endocrine immaturity. We compared mRNA profiles of neonatal and 10-weeks old rat beta cells to see how their gene expression changes with functional maturation. Neonatal beta cells showed a lower glucose-inducible increment in insulin production than adult cells. This was in part explained by basal protein synthetic hyperactivity of neonatal cells: while at 2.5mM glucose 80% of neonatal beta cells were recruited into active protein synthesis, 10 mM glucose was required to achieve a similar fraction of active adult beta cells. Besides this progressive recruitment, glucose exerted in both age groups an additional amplifying effect in the recruited cells, but clearly more so in adult beta cells that showed a higher maximal synthetic capacity/cell. Neonatal beta cells balanced an advanced endocrine differentiation as judged by their mRNA expression of conserved beta cell marker genes, with higher expression of genes involved in cell cycle and development. One example, Delta-like 1 homolog (DLK1) was used to investigate if neonatal beta cells with basal hyperactivity corresponded to a more immature subset, as marked by high DLK1. Neonatal pancreas contained distinct subsets of DLK1high and DLK1low insulin-expressing cells, but both showed equal hyperactivity. We conclude that neonatal beta cells combine advanced endocrine maturation with traits of residual developmental immaturity. If DLK1 is used as marker for the latter, the basal hyperactivity which proved to be a cardinal feature of neonatal beta cells is not a direct reflection of their residual immaturity.
Functional characteristics of neonatal rat β cells with distinct markers.
Sex, Age, Specimen partView Samples
The aim of this data set is to perform a differential expression analysis between wild type eye-antennal imaginal disc and discs that are homozygous glass mutant gl[60j]. This data set is used to validate Glass target gene predictions identified by i-cisTarget on a set of conserved eye-specific genes. Overall design: RNA-seq was performed in eye-antennal imaginal discs of two D.melanogaster wild-type strains (Canton S and strain RAL-208 (Jordan et al. 2007, Ayroles et al. 2009)), representing two biological replicates; and in glass mutant (gl[60j]) discs for two technical replicates.
Comparative motif discovery combined with comparative transcriptomics yields accurate targetome and enhancer predictions.
Specimen part, Cell line, SubjectView Samples
Analysis of p53 binding sites using multiplex enhancer reporter assays, ChIP-seq data and RNA-seq data. Transcription factors establish and maintain the specific transcriptome of a cell by binding to genomic regulatory regions, thereby regulating the transcription of their target genes. Like many transcription factors, the DNA sequence-specific binding preferences of p53 are known. However, it remains largely unclear what distinguishes functional enhancers from other bound genomic regions that have no regulatory activity. In addition, the genome is scattered with seemingly perfect recognition sequences that remain unoccupied. To disentangle the rules of genome-wide p53 binding, we employed two complementary techniques of multiplex enhancer-reporter assays, one using barcoded reporters and the other using enhancer self-transcription. We compared the activity of more than one thousand candidate p53 enhancers under loss and gain of p53 conditions and identified several hundred high-confidence p53-responsive enhancers. Strikingly, the large majority (99%) of these target enhancers can be characterized and distinguished from negative sequences by the occurrence of a single p53 binding site. By training a machine learning classifier on these data, and integrating the resulting genome-wide predictions with fifteen publicly available human p53 ChIP-seq data sets, we identified a consensus set of 1148 functional p53 binding sites in the human genome. Unexpectedly, this direct p53 cistrome is invariably used between cell types and experimental conditions, while differences between experiments can be largely attributed to indirect non-functional binding. Our data suggest that direct p53 enhancers function in a context-independent manner and do not contain obvious combinatorial complexity of binding sites for multiple transcription factors. They represent a class of unsophisticated cell-autonomous enhancers with a single binding site, distinct from complex developmental enhancers that integrate signals from multiple transcription factors. This suggests that context-dependent regulation of p53 target genes is not encoded in the p53 enhancer, but at different upstream or downstream layers of the cell''s gene regulatory network. Overall design: RNA-seq on MCF7 cells with p53 stable knockdown.
Multiplex enhancer-reporter assays uncover unsophisticated TP53 enhancer logic.
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To evaluate the prognostic relevance of molecular subtypes and key transcription factors in pancreatic ductal adenocarcinoma (PDAC), we performed gene expression analysis of whole-tumor tissue obtained from 118 surgically resected PDAC and 13 control samples.
Prognostic relevance of molecular subtypes and master regulators in pancreatic ductal adenocarcinoma.
Specimen partView Samples
RNA from two murine mesothelioma cell lines (AC29 and AB1) was extracted and hybridized to Affymetrix Microarrays to compare gene expression. Both mesothelioma cell lines were established following intraperitoneal introduction of crocidolite (asbestos) fibers (Davis et al. 1992) in CBA mice (AC29 cell line), and BALB/c mice (AB1).
Depletion of Tumor-Associated Macrophages with a CSF-1R Kinase Inhibitor Enhances Antitumor Immunity and Survival Induced by DC Immunotherapy.
Genome control is operated by transcription factors (TF) controlling their target genes by binding to promoters and enhancers. Conceptually, the interactions between TFs, their binding sites, and their functional targets are represented by gene regulatory networks (GRN). Deciphering in vivo GRNs underlying organ development in an unbiased genome-wide setting involves identifying both functional TF-gene interactions and physical TF-DNA interactions. To reverse-engineer the GRN of eye development in Drosophila, we performed RNA-seq across 72 genetic perturbations and sorted cell types, and inferred a co-expression network. Next, we derived direct TF-DNA interactions using computational motif inference, ultimately connecting 241 TFs to 5632 direct target genes through 24926 enhancers. Using this network we found network motifs, cis-regulatory codes, and new regulators of eye development. We validate the predicted target regions of Grainyhead by ChIP-seq and identify this factor as a general co-factor in the eye network, being bound to thousands of nucleosome-free regions. Overall design: RNA-seq gene expression profiling across Drosophila 3rd instar larval wild type tissues (brain, eye-antennal and wing discs), specific cell types from the eye-antennal disc, sorted by FACS, and genetic perturbations (TF mutants, TF over-expression, and TF RNAi knockdown).
Mapping gene regulatory networks in Drosophila eye development by large-scale transcriptome perturbations and motif inference.
Specimen part, SubjectView Samples
Recent studies have reported that glycosphingolipids (GSL) might be involved in obesity induced insulin resistance. Those reports suggested that inhibition of GSL biosynthesis in animals ameliorated insulin sensitivity accompanied with improved glycemic control leading to decreased liver steatosis in obese mice. In addition, GSL depletion altered hepatic secretory function. In those studies, ubiquitously acting inhibitors for GSL-biosynthesis have been used to inhibit function of the enzyme Ugcg (UDP-glucose:ceramide glucosyltransferase), catalyzing the first step of the glucosylceramide based GSL-synthesis pathway. In the present study, a genetic approach for GSL deletion in hepatocytes was chosen to achieve full inhibition of GSL synthesis and to prevent possible adverse effects caused by Ugcg-inhibitors. Using the Cre/loxP system under control of the albumin promoter, GSL biosynthesis in hepatocytes and their release into the plasma could be effectively blocked. Deletion of GSL in hepatocytes did not change quantity of bile excretion through the biliary duct. Total bile salt content in bile-, feces- and plasma from mutant mice showed no difference as compared to control animals. Cholesterol concentration in liver-, bile-, feces- and plasma-samples remained unaffected. Lipoprotein concentration in plasma-samples in mutant animals reached similar levels as in their control littermates. No alteration in glucose tolerance after intraperitoneal application of glucose and insulin appeared in mutant animals. A preventive effect of GSL-deficiency on development of liver steatosis after high fat diet feeding could not be observed.
Hepatic glycosphingolipid deficiency and liver function in mice.
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Microphthalmia-associated transcription factor (MITF) is the master regulator of the melanocyte lineage. By tandem affinity purification and mass spectrometry, we present a comprehensive characterisation of the MITF interactome comprising multiple novel cofactors involved in transcription, DNA replication and repair and chromatin organisation, including a BRG1 chromatin remodelling complex comprising CHD7. BRG1 is essential for melanoma cell proliferation in vitro and for normal melanocyte development in vivo. MITF and SOX10 actively recruit BRG1 to a set of MITF-associated regulatory elements (MAREs) at active enhancers. MITF, SOX10 and YY1 bind between two BRG1-occupied nucleosomes thus defining both a combinatorial signature of transcription factors essential for the melanocyte lineage and a specific chromatin organisation of MAREs. Nevertheless, BRG1 silencing enhances MITF occupancy at MAREs showing that BRG1 acts to promote dynamic MITF interactions with chromatin. Overall design: 19 samples corresponding to mRNA profiles of 501Mel and Hermes3A after MITF, BRG1 or control shRNA-mediated knockdown were generated by deep sequencing in triplicate (in duplicate for 501_shMITF and corresponding control 501_shSCR2), using HiSeq2500.
Transcription factor MITF and remodeller BRG1 define chromatin organisation at regulatory elements in melanoma cells.
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