RNA editing is a mutational mechanism that specifically alters the nucleotide content in sets of transcripts while leaving their cognate genomic blueprint intact. Editing has been detected from bulk RNA-seq data in thousands of distinct transcripts, but apparent editing rates can vary widely (from under 1% to almost 100%). These observed editing rates could result from approximately equal rates of editing within each individual cell in the bulk sample, or alternatively, editing estimates from a population of cells could reflect an average of distinct, biologically significant editing signatures that vary substantially between individual cells in the population. To distinguish between these two possibilities we have constructed a hierarchical Bayesian model which quantifies the variance of editing rates at specific sites using RNA-seq data from both single cells and a cognate bulk sample consisting of ~ 106 cells. The model was applied to data from murine bone-marrow derived macrophages and dendritic cells, and predicted high variance for specific edited sites in both cell types tested. We then 1 validated these predictions using targeted amplification of specific editable transcripts from individual macrophages. Our data demonstrate substantial variance in editing signatures between single cells, supporting the notion that RNA editing generates diversity within cellular populations. Such editing-mediated RNA-level sequence diversity could contribute to the functional heterogeneity apparent in cells of the innate immune system. Overall design: 26 samples were subjected to RNA-seq: 24 single WT macrophages, and 2 bulk samples (Apobec1 WT and KO macrophages), consisting of 500,000-1 million cells each.
RNA editing generates cellular subsets with diverse sequence within populations.
Specimen part, Cell line, Subject
View SamplesWnt signaling is intrinsic to mouse embryonic stem cell self-renewal. Therefore it is surprising that reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) is not strongly enhanced by Wnt signaling. Here, we demonstrate that active Wnt signaling inhibits the early stage of reprogramming to iPSCs, while it is required and even stimulating during the late stage. Mechanistically, this biphasic effect of Wnt signaling is accompanied by a change in the requirement of all four of its transcriptional effectors: Tcf1, Lef1, Tcf3, and Tcf4. For example, Tcf3 and Tcf4 are stimulatory early but inhibitory late in the reprogramming process. Accordingly, ectopic expression of Tcf3 early in reprogramming combined with its loss-of-function late enables efficient reprogramming in the absence of ectopic Sox2. Together, our data indicate that the step-wise process of reprogramming to iPSCs is critically dependent on the stage-specific control and action of all four Tcfs and Wnt signaling.
Stage-specific regulation of reprogramming to induced pluripotent stem cells by Wnt signaling and T cell factor proteins.
Specimen part, Time
View SamplesThe bromodomain and extraterminal (BET) protein Brd4 is a validated drug target in leukemia, yet its regulatory function in this disease is not well understood. Here, we show that Brd4 chromatin occupancy in acute myeloid leukemia closely correlates with the hematopoietic transcription factors (TFs) Pu.1, Fli1, Erg, C/EBPa, C/EBPß, and Myb at nucleosome-depleted enhancer and promoter regions. We provide evidence that these TFs, in conjunction with the lysine acetyltransferase activity of p300/CBP, facilitate Brd4 recruitment to their occupied sites to promote transcriptional activation. Moreover, chemical inhibition of BET bromodomains is found to suppress the functional output each hematopoietic TF, thereby interfering with essential lineage-specific transcriptional circuits in this disease. These findings reveal a chromatin-based signaling cascade comprised of hematopoietic TFs, p300/CBP, and Brd4, which supports leukemia maintenance and is suppressed by BET bromodomain inhibition. Overall design: PolyA selected RNA-Seq for drug treated or shRNA-expressing MLL-AF9 transformed acute myeloid leukemia cells (RN2)
BET Bromodomain Inhibition Suppresses the Function of Hematopoietic Transcription Factors in Acute Myeloid Leukemia.
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View SamplesAssessment of the putative differential gene expression profiles in high osmolality-treated bovine nucleus pulposus intervertebral disc cells for a short (5 h) and a long (24 h) time period. Identification of novel genes up- or down-regulated as an early or a late response to hyperosmotic stress.
Deficiency in the α1 subunit of Na+/K+-ATPase enhances the anti-proliferative effect of high osmolality in nucleus pulposus intervertebral disc cells.
Specimen part
View SamplesThe metabolic syndrome (MetS) is characterized by the presence of metabolic abnormalities that include abdominal obesity, dyslipidemia, hypertension, increased blood glucose/insulin resistance, hypertriglyceridemia and increased risk for cardiovascular disease (CVD). The ApoE*3Leiden.human Cholesteryl Ester Transfer Protein (ApoE3L.CETP) mouse model manifests several features of the MetS upon high fat diet (HFD) feeding. Moreover, the physiological changes in the white adipose tissue (WAT) contribute to MetS comorbidities. The aim of this study was to identify transcriptomic signatures in the gonadal WAT of ApoE3L.CETP mice in discrete stages of diet-induced MetS.
Transcriptome analysis of the adipose tissue in a mouse model of metabolic syndrome identifies gene signatures related to disease pathogenesis.
Sex, Age, Specimen part
View SamplesThe formation of neuronal connections requires the precise guidance of developing axons towards their targets. In the Drosophila visual system, photoreceptor neurons (R cells) project from the eye into the brain. These cells are grouped into some 750 clusters comprised of eight photoreceptors or R-cells each. R cells fall into three classes, R1-R6, R7 and R8. Posterior R8 cells are the first to project axons into the brain. How these axons select a specific pathway is not known.
Robo-3--mediated repulsive interactions guide R8 axons during Drosophila visual system development.
Specimen part
View SamplesIn polygenic disorders we do not know exactly, how many genes are involved in the pathomechanism, but the analysis of fetal gene expression can get us closer to the solution. In our study we were searching for the genetic background of the polygenic neural tube defect, which is the second most common birth defect in the world (1 in 1000 live births). Our data revealed novel candidate genes, like SLAP, LST1 and BENE, which can play an important role in the pathogenesis of neural tube defects. We created a data warehouse from the results, suitable for further analysis. This study also demonstrates that a routinely collected amount of amniotic fluid (as small as 6 mL) is enough to successfully hybridize isolated RNA to expression arrays, making the ability to use the technique from normally collected amniotic fluid samples.
Use of routinely collected amniotic fluid for whole-genome expression analysis of polygenic disorders.
Specimen part, Disease, Disease stage
View SamplesHuman SLK cells were infected with wildtype (wt) and LANA knockout (KO) Kaposi's sarcoma-associated herpesvirus (KSHV), separately for 3 days. Cellular gene expression changes were identified upon the wild type and LANA KO KSHV virus infection compared to the uninfected SLK cells using the human gene expression microarray U133plus2.0.
LANA-Mediated Recruitment of Host Polycomb Repressive Complexes onto the KSHV Genome during De Novo Infection.
Cell line, Time
View SamplesA growing number of studies on gynecological cancers (GCs) have revealed potential gene markers associated either with the pathogenesis and progression of the disease on representing putative targets for therapy and treatment of cervical (CC), endometrial (EC) and vulvar cancer (VC). However, quite a little overlap is found between these data. In this study we combined data from the three GCs integrating gene expression profile analysis.
Profiling of Discrete Gynecological Cancers Reveals Novel Transcriptional Modules and Common Features Shared by Other Cancer Types and Embryonic Stem Cells.
Specimen part, Disease, Disease stage
View SamplesEvolution of antibiotic resistance in microbes is frequently achieved by acquisition of spontaneous mutations during antimicrobial therapy. Here we demonstrate that inactivation of a central regulator of iron homeostasis (fur) facilitates laboratory evolution of ciprofloxacin resistance in Escherichia coli. To decipher the underlying molecular mechanisms, we first performed a global transcriptome analysis and demonstrated a substantial reorganization of the Fur regulon in response to antibiotic treatment. We hypothesized that the impact of Fur on evolvability under antibiotic pressure is due to the elevated intracellular concentration of free iron and the consequent enhancement of oxidative damage-induced mutagenesis. In agreement with expectations, over-expression of iron storage proteins, inhibition of iron transport, or anaerobic conditions drastically suppressed the evolution of resistance, while inhibition of the SOS response-mediated mutagenesis had no such effect in fur deficient population. In sum, our work revealed the central role of iron metabolism in de novo evolution of antibiotic resistance, a pattern that could influence the development of novel antimicrobial strategies.
Perturbation of iron homeostasis promotes the evolution of antibiotic resistance.
No sample metadata fields
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