Mareks disease (MD) is an economically significant disease in chickens caused by the highly oncogenic Mareks disease virus (MDV). A major unanswered question is the mechanism of MDV-induced tumor formation. Meq, a bZIP transcription factor discovered in the 1990s, is critically involved in viral oncogenicity but only a few of its host target genes have been described impeding our understanding of MDV-induced tumorigenesis. Using ChIP-seq and microarray analysis, a high confidence list of Meq-binding sites in the chicken genome and a global transcriptome of Meq-responsive genes was generated. Meq binding sites were found to be enriched in the promoter regions of up-regulated genes, but not in those of down-regulated genes. ChIP-seq was also performed for c-Jun, a known heterodimeric partner of Meq. Close location of binding sites of Meq and c-Jun was noted, suggesting cooperativity between these two factors in modulating transcription. Pathway analysis indicated that Meq transcriptionally regulates many genes that are part of several signaling pathways include the ERK/MAPK, Jak-STAT, and ErbB pathways that are critical for oncogenesis and/or include signaling mediators involved in apoptosis. Meq activates oncogenic signaling cascades by transcriptionally activating major kinases in the ERK/MAPK pathway and simultaneously repressing phosphatases, as verified using inhibitors of MEK and ERK1/2 in a cell proliferation assay. This study provides significant insights into the mechanistic basis of Meq-dependent cell transformation.
Integrated analyses of genome-wide DNA occupancy and expression profiling identify key genes and pathways involved in cellular transformation by a Marek's disease virus oncoprotein, Meq.
Specimen part
View SamplesThe goal of this study was to define relationships between peripheral blood miRNAs and mRNAs of women undergoing idiopathic preterm labor (PTL) and compare network level changes to control women that deliver at term.Using RNA Sequencing we have performed global miRNA and mRNA profiling in both monocytes and whole blood leukocytes of women who underwent PTL (N=15) matched to non-pathological controls (N=30) as a part of the Ontario Birth Study cohort. We have identified differentially expressed miRNAs, mRNAs and pathways associated with PTL. Intriguingly, we found perturbations in many cellular signaling pathways, particularly in interleukin signaling. We also predicted mRNA targets for specific miRNAs and used these predictions to build putative miRNA-mRNA networks. We identified 6 miRNAs significantly associated with PTL whose expression is negatively correlated with expression of 14 predicted mRNA targets that are also significantly associated with PTL. Overall design: miRNA and mRNA were quantified from whole blood and monocytes of women undergoing spontaneous preterm labor compared to nonlabor controls matched on gestational age
Comparative analysis of gene expression in maternal peripheral blood and monocytes during spontaneous preterm labor.
Subject
View SamplesFollistatin is a folliculogenesis regulating protein that has been found in relatively high concentration in the female ovarian tissues. Follistatin acts as an antagonist to the function of Activin, which is often found elevated in ovarian carcinogenesis and thus presents a possibility for therapeutic intervention in controlling ovarian cancer. Most of the ovarian cancer occurs in its ovarian surface epithelium (OSE) cells. Although breast cancer susceptibility gene 1 (BRCA1) is a known tumor suppressor for breast cancer but its role in ovarian cancer is beginning to unfold. We have shown that in ovarian carcinoma cells (SKOV3), stable overexpression of BRCA1 stimulates Follistatin secretion and simultaneously downregulates Activin expression. Moreover, knock down of BRCA1 in immortalized OSE (IOSE) cells from human ovarian tissue demonstrates downregulation of Follistatin secretion with simultaneous up regulation of Activin expression. IOSE cells generated from an ovarian cancer patient with BRCA1 mutation failed to secrete Follistatin in the medium. Our results indicate a novel function for BRCA1 in the form of regulation of the expression of Follistatin in the ovarian cells.
BRCA1 regulates follistatin function in ovarian cancer and human ovarian surface epithelial cells.
Specimen part, Cell line
View SamplesA single replicate of exponentially growing DT40 CL18 chicken B lymphoma cells were harvested and extracted RNA was subjected to Illumina GAIIx paired-end sequencing to determine global gene expression. Overall design: Single replicate RNA-seq expression analysis of DT40 cells.
Third Report on Chicken Genes and Chromosomes 2015.
Specimen part, Cell line, Subject
View SamplesMicroarray expression profiling was used to identify genes expressed misexpressed in wild-type Arabidopsis seedlings treated with 5-aza-2 deoxyctidine (5AC) or trichostatin A (TSA), and in decrease in dna methylation1 (ddm1) mutant seedlings.
Changes in global gene expression in response to chemical and genetic perturbation of chromatin structure.
Specimen part
View SamplesBiological systems display extraordinary robustness. Robustness of transcriptional enhancers results mainly from clusters of binding sites for the same transcription factor, and it is not clear how robust enhancers can evolve loss of expression through point mutations. Here, we report the high-resolution functional dissection of a robust enhancer of the shavenbaby gene that has contributed to morphological evolution. We found that robustness is encoded by many binding sites for the transcriptional activator Arrowhead and that, during evolution, some of these activator sites were lost, weakening enhancer activity. Complete silencing of enhancer function, however, required evolution of a binding site for the spatially restricted potent repressor Abrupt. These findings illustrate that recruitment of repressor binding sites can overcome enhancer robustness and may minimize pleiotropic consequences of enhancer evolution. Recruitment of repression may be a general mode of evolution to break robust regulatory linkages. Overall design: 8 samples are analyzed: background GFP- and target GFP+ cells from four independent sortings.
Evolved Repression Overcomes Enhancer Robustness.
Specimen part, Subject
View SamplesPdgfra-expressing (Pdgfra+) cells have been implicated as progenitors in many mesenchymal tissues. To further characterize Pdgfra+ cells during alveologensis, we performed single-cell RNA sequencing (scRNA-Seq) analysis using fluorescence-activated cell sorting (FACS) sorted GFP+ cells from Pdgfra-GFP lungs at P7 and P15. Overall design: We perfomed 10X genomics single-cell RNA-seq of Pdgfra-GFP+ cells at P7 and P15
<i>Pdgfra</i> marks a cellular lineage with distinct contributions to myofibroblasts in lung maturation and injury response.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Divergent whole-genome methylation maps of human and chimpanzee brains reveal epigenetic basis of human regulatory evolution.
No sample metadata fields
View SamplesWe identified human-specific gene expression patterns in the brain by comparing expression with chimpanzee and rhesus macaque
Divergent whole-genome methylation maps of human and chimpanzee brains reveal epigenetic basis of human regulatory evolution.
No sample metadata fields
View SamplesGlucose is the most important metabolic substrate of the retina and maintenance of nor-moglycemia is an essential challenge for diabetic patients. Glycemic excursions could lead to cardiovascular disease, nephropathy, neuropathy and retinopathy. We recently showed that hy-poglycemia induced retinal cell death in mouse via caspase 3 activation and glutathione (GSH) decrease. Ex vivo experiments in 661W photoreceptor cells confirmed the low-glucose induction of death via superoxide production and activation of caspase 3, which was concomitant with a decrease of GSH content. We evaluate herein retinal gene expression 4 h and 48 h after insulin-induced hypoglycemia. Microarray analysis demonstrated clusters of genes whose expression is modified by hypoglycemia and we discuss the potential implication of those genes in retinal cell death. In addition, we highlight, by gene set enrichment analysis, three important pathways, including KEGG lysosomes, KEGG GSH metabolism and REACTOME apoptosis pathways. We tested the effect of recurrent hypoglycemia (three successive 5h periods of hypoglycemia separated by 48 h recovery) on retinal cell death. Interestingly, exposure to multiple hypoglycemic events prevents retinal cell death and GSH decrease, or adapts the retina to external stress by restoring GSH level comparable to control situation. We hypothesize that scavenger GSH is a key compound in this apoptotic process, and maintaining normal GSH level, as well as a strict glycemic control, may represent a therapeutic challenge in order to avoid side effects of diabetes, especially diabetic retinopathy.
Biological Characterization of Gene Response to Insulin-Induced Hypoglycemia in Mouse Retina.
Sex, Age, Specimen part
View Samples