Chromatin occupancy of key transcriptional regulators in P493-6 cells with various levels of c-Myc expression
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Richard Young
PROVIDER: E-GEOD-42262 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Excessive expression of c-Myc occurs frequently in human cancers, where high levels are associated with tumor aggression and poor clinical outcome, but the effect of high levels of c-Myc on global gene regulation is poorly understood. We report here that in tumor cells expressing high levels of c-Myc, the transcription factor binds to E-box sequences in the core promoters of most actively transcribed genes and, unexpectedly, the enhancers of these active genes. The predominant effect of increasing c-Myc levels at both proximal and distal promoter elements is to produce higher levels of transcription at existing active genes by promoting RNA polymerase II elongation, as opposed to stimulating transcription of novel target genes. Our results argue that c-Myc overexpression drives increased transcription of growth-promoting genes, and does so by amplifying the levels of transcripts associated with the entire gene expression program of the cancer cell. Thus, excess c-Myc functions to elicit the transcriptional amplification of existing active genes through the invasion of enhancers across the cancer cell genome, thereby reducing the rate-limiting constraints required for continuous tumor growth and proliferation. ChIP-Seq of multiple factors and histone modifications in a variety of human tumor cell lines
2012-04-04 | E-GEOD-36354 | biostudies-arrayexpress
Project description:The c-myc proto-oncogene product, Myc, is a transcription factor that binds thousands of genomic loci. Recent work suggested that rather than up- and down-regulating selected groups of genes, Myc targets all active promoters and enhancers in the genome (a phenomenon termed "invasion") and acts as a general amplifier of transcription. However, the available data did not readily discriminate between direct and indirect effects of Myc on RNA biogenesis. We addressed this issue with genome-wide chromatin immunoprecipitation and RNA expression profiles during B-cell lymphomagenesis in mice, in cultured B-cells and fibroblasts. Consistent with long-standing observations, we detected general increases in total RNA or mRNA copies per cell (hereby termed "amplification") when comparing actively proliferating cells with control quiescent cells: this was true whether cells were stimulated by mitogens (requiring endogenous Myc for a proliferative response) or by deregulated, oncogenic Myc activity. RNA amplification and promoter/enhancer invasion by Myc were separable phenomena that could occur without one another. Moreover, whether or not associated with RNA amplification, Myc drove the differential expression of distinct subsets of target genes. Hence, while having the potential to interact with all active/poised regulatory elements in the genome, Myc does not directly act as a global transcriptional amplifier. Instead, our results imply that Myc activates and represses transcription of discrete gene sets, leading to changes in cellular state that can in turn feed back on global RNA production and turnover. Mapping c-Myc, RNAPII and H3K4me3, H3K4me1 and H3K27ac in four different models of Myc regulation Note: GEO Sample GSM894093 was used as input sample to generate processed data files P493.Myc.NoMyc.bed, P493.Myc.LowMyc.bed, P493.Myc.HighMyc.bed, P493.Myc.t1h.bed, P493.Myc.t24h.bed, P493.Pol2.NoMyc.bed, P493.Pol2.t24h.bed
2014-07-07 | E-GEOD-51004 | biostudies-arrayexpress
Project description:Gene expression analysis is a widely used and powerful method for investigating the transcriptional behavior of biological systems, for classifying cell states in disease and for many other purposes. Recent studies indicate that common assumptions currently embedded in experimental and analytical practices can lead to misinterpretation of global gene expression data. We discuss these assumptions and describe solutions that should minimize erroneous interpretation of gene expression data from multiple analysis platforms. RNA was extracted from cells expressing low or high levels of c-Myc. A panel of synthetic RNA's was added to these populations, based on cell number. Total RNA was then extracted and processed on Affymetrix microarrays in biological duplicate.
2012-10-25 | E-GEOD-40782 | biostudies-arrayexpress
Project description:Gene expression analysis is a widely used and powerful method for investigating the transcriptional behavior of biological systems, for classifying cell states in disease and for many other purposes. Recent studies indicate that common assumptions currently embedded in experimental and analytical practices can lead to misinterpretation of global gene expression data. We discuss these assumptions and describe solutions that should minimize erroneous interpretation of gene expression data from multiple analysis platforms. Polyadenylated RNA depleted of ribosomal content was used for preparation of two independent sequencing libraries (low-Myc & high-Myc). A panel of synthetic RNA's was added to these populations, based on cell number.
2012-10-25 | E-GEOD-40783 | biostudies-arrayexpress
Project description:Myc is a well known transcription factor with important roles in cell cycle, apoptosis and cellular transformation. Long non-coding (lnc)RNAs have recently emerged as a important class of regulatory RNAs. Here, we show that lncRNAs are an extensive component of the Myc-regulated transcriptional program. Using the P493-6 inducible Myc model we demonstrate that both Myc-induced mRNAs and lncRNAs were significant enriched for Myc binding sites. In contrast to Myc-repressed mRNAs, Myc-repressed lncRNAs were significantly enriched for Myc binding sites. Subcellular localization analysis revealed that Myc-repressed lncRNAs and mRNAs are enriched in the nucleus while Myc-induced lncRNAs and mRNAs are enriched both in the cytoplasm and nucleus. Parallel analysis of differentially expressed lncRNAs and mRNAs identified 105 lncRNA-mRNA pairs that were in close vicinity, indicative for regulation in cis. To support the potential relevance of the Myc-regulated lncRNAs in cellular transformation, we analyzed their expression in primary Myc-high and Myc-low B-cell lymphomas. In total, 54% of the lncRNAs differentially expressed between the lymphoma subsets were identified as Myc-regulated in P493-6 cells. This study is the first to show that lncRNAs are an important factor within the Myc-regulated transcriptional program and indicates a marked difference between Myc-repressed lncRNAs and mRNAs. Arrays: The total, cy3 labeled fraction and the cytoplasmic or nuclear, cy5 labeled fraction was hybridized on the same array. Data was imported and analyzed as a single color array. Expression of all known mRNAs and >10 000 lncRNAs was assessed in P493-6 B cells with low c-myc levels
2015-02-01 | E-GEOD-59478 | biostudies-arrayexpress
Project description:Myc is a well known transcription factor with important roles in cell cycle, apoptosis and cellular transformation. Long non-coding (lnc)RNAs have recently emerged as a important class of regulatory RNAs. Here, we show that lncRNAs are an extensive component of the Myc-regulated transcriptional program. Using the P493-6 inducible Myc model we demonstrate that both Myc-induced mRNAs and lncRNAs were significant enriched for Myc binding sites. In contrast to Myc-repressed mRNAs, Myc-repressed lncRNAs were significantly enriched for Myc binding sites. Subcellular localization analysis revealed that Myc-repressed lncRNAs and mRNAs are enriched in the nucleus while Myc-induced lncRNAs and mRNAs are enriched both in the cytoplasm and nucleus. Parallel analysis of differentially expressed lncRNAs and mRNAs identified 105 lncRNA-mRNA pairs that were in close vicinity, indicative for regulation in cis. To support the potential relevance of the Myc-regulated lncRNAs in cellular transformation, we analyzed their expression in primary Myc-high and Myc-low B-cell lymphomas. In total, 54% of the lncRNAs differentially expressed between the lymphoma subsets were identified as Myc-regulated in P493-6 cells. This study is the first to show that lncRNAs are an important factor within the Myc-regulated transcriptional program and indicates a marked difference between Myc-repressed lncRNAs and mRNAs. P493-6: 72h Tet treated (low c-myc levels), t=4h (intermediate c-myc levels), t=24h (high c-myc levels), untreated (steady state c-myc levels) Expression of all known mRNAs and >10 000 lncRNAs was assessed in P493-6 B cells with different c-myc levels
2015-02-01 | E-GEOD-59477 | biostudies-arrayexpress
Project description:The c-myc proto-oncogene product, Myc, is a transcription factor that binds thousands of genomic loci. Recent work suggested that rather than up- and down-regulating selected groups of genes, Myc targets all active promoters and enhancers in the genome (a phenomenon termed "invasion") and acts as a general amplifier of transcription. However, the available data did not readily discriminate between direct and indirect effects of Myc on RNA biogenesis. We addressed this issue with genome-wide chromatin immunoprecipitation and RNA expression profiles during B-cell lymphomagenesis in mice, in cultured B-cells and fibroblasts. Consistent with long-standing observations, we detected general increases in total RNA or mRNA copies per cell (hereby termed "amplification") when comparing actively proliferating cells with control quiescent cells: this was true whether cells were stimulated by mitogens (requiring endogenous Myc for a proliferative response) or by deregulated, oncogenic Myc activity. RNA amplification and promoter/enhancer invasion by Myc were separable phenomena that could occur without one another. Moreover, whether or not associated with RNA amplification, Myc drove the differential expression of distinct subsets of target genes. Hence, while having the potential to interact with all active/poised regulatory elements in the genome, Myc does not directly act as a global transcriptional amplifier. Instead, our results imply that Myc activates and represses transcription of discrete gene sets, leading to changes in cellular state that can in turn feed back on global RNA production and turnover. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-07-07 | E-GEOD-51011 | biostudies-arrayexpress
Project description:In order to examine the consequences of Myc and Lin-28B induction on the transcriptome, P493-6 cells (human EBV-transformed B lymphocytes) were infected with a retrovirus that produces human Lin-28B or empty virus as a control. Gene expression profiles were then monitored in the high and low Myc state using Affymetrix microarrays. Experiment Overall Design: RNA from retrovirally-infected cells with high or low Myc expression was isolated and hybridized to Affymetrix microarrays.
2009-03-14 | E-GEOD-14302 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2015-02-01 | E-GEOD-59480 | biostudies-arrayexpress
Project description:Constitutively active MYC and reactivated telomerase often co-exist in cancers. While the reactivation of telomerase is thought to be essential for replicative immortality, MYC, in conjunction with co-factors, confers several growth advantages to cancer cells. However, it is unclear which co-factors sustain elevated MYC activity in tumours . Here, we identify TERT, the catalytic subunit of telomerase, as a novel regulator of MYC stability in cancers. Binding of TERT to MYC stabilizes its levels on chromatin, contributing to either activation or repression of its target genes. Mechanistically, TERT regulates MYC ubiquitination and stability, and this effect of TERT is independent of its role on telomeres. Genetic inhibition and knocking out of TERT phenocopied the loss of MYC, resulting in reduced disease burden of early- and late-stage MYC-driven murine lymphomas. Conversly, the ectopic expression of TERT could substitute for reduced MYC in these functions. Finally we show that TERT null mice, unlike Terc null mice, show delayed onset of MYC induced lymphomagenesis. Accordingly, inhibiting TERT function in primary human leukemia cells blocked the expression of MYC targets, while Terc depletion had no effects . Based on our data, we conclude that the re-expression of TERT, a direct MYC target in tumors, provides a feed-forward mechanism to potentiate MYC-dependent oncogenesis. ChIP was performed using anti-MYC (sc-764) in primary lymphoma cells from Eµ-Myc;Tert -/- mice, Eµ-Myc;Tert +/+ mice, or in P493 cells treated with shTert, P493 shTerc and shControl.
2015-04-23 | E-GEOD-60223 | biostudies-arrayexpress