This SuperSeries is composed of the SubSeries listed below.
Promoter-proximal transcription factor binding is transcriptionally active when coupled with nucleosome repositioning in immediate vicinity.
Specimen part, Disease, Cell line
View SamplesNon-metastatic 2 (NME2) is an established metastases suppressor in multiple human cancer types. However, the molecular mechanisms of NME2 action remain insufficiently resolved. We recently validated the transcription regulatory activity of NME2 with respect to control of proto-oncogene c-MYC expression. We hypothesized that large scale transcriptional potential of NME2 may be at the core of metastases suppression by NME2. Using a combination of high throughput genomic assays such as chromatin immunoprecipitation coupled to promoter array hybridization (ChIP-chip) and gene expression profiling, we characterized the transcriptional roles of NME2. Specifically, we found a set of NME2 target genes which changed expression upon selective depletion of NME2 in a lung cancer cell line, A549. The analysis of gene expression suggested control of various biological pathways esp. cell adhesion and apoptosis by NME2 target genes which could be important in regulation of metastases.
Promoter-proximal transcription factor binding is transcriptionally active when coupled with nucleosome repositioning in immediate vicinity.
Specimen part, Cell line
View SamplesIt is widely believed that reorganization of nucleosomes result in availability of binding sites that engage transcription factors during eukaryotic gene regulation. Recent findings, on the other hand, suggest that transcription factors induced as a result of physiological perturbations directly (or in association with chromatin modifiers) may alter nucleosome occupancy to facilitate DNA binding. Although, together these suggest a close relationship between transcription factor binding and nucleosome reorganization, the nature of the inter-dependency, or to what extent it influences regulatory transcription is not clear. Moreover, since most studies used physiolgical pertubations that induced multiple transcription factor chromatin modifiers, the relatively local (or direct) effect of transcription factor binding on nucleosome occupancy remains unclear. With these in mind, we used a single transcription factor to induce physiological changes, representing metastatic (aggressive cancer) and the corresponding non-metastatic state, in human cancer cells. Following characterization of the two states (before and after induction of the transcription factor) we determined: (a) genome wide binding sites of the transcription factor, (b) promoter nucleosome occupancy and (c) transcriptome profiles, independently in both conditions. Interestingly, we find only ~20% of TF binding results from nucleosome reorganization - however, almost all corresponding genes were transcriptionally altered. Whereas, in cases where TF-occupancy was independent of nucleosome repositioning (in close vicinity), or co-occurred with nucleosomes, only a small fraction of the corresponding genes were expressed/repressed. Together, these indicate a model where TF occupancy only when coupled with nucleosome repositioning in close proximity is transcriptionally active. This, to our knowledge, for the first time also helps explain why genome wide TF occupancy (e.g., from ChIP-seq) is typically associated with only a small fraction of genes that change expression.
Promoter-proximal transcription factor binding is transcriptionally active when coupled with nucleosome repositioning in immediate vicinity.
Specimen part, Cell line
View SamplesAdvantages of RNA-Seq over array based platforms are quantitative gene expression and discovery of expressed single nucleotide variants (eSNVs) and fusion transcripts from a single platform, but the sensitivity for each of these characteristics is unknown. We measured gene expression in a set of manually degraded RNAs, nine pairs of matched fresh-frozen, and FFPE RNA isolated from breast tumor with the hybridization based, NanoString nCounter, (226 gene panel) and with whole transcriptome RNA-Seq using RiboZeroGold ScriptSeq V2 library preparation kits. We performed correlation analyses of gene expression between samples and across platforms. We then specifically assessed whole transcriptome expression of lincRNA and discovery of eSNVs and fusion transcripts in the FFPE RNA-Seq data. For gene expression in the manually degraded samples, we observed Pearson correlation of >0.94 and >0.80 with NanoString and ScriptSeq protocols respectively. Gene expression data for matched fresh-frozen and FFPE samples yielded mean Pearson correlations of 0.874 and 0.783 for NanoString (226 genes) and ScriptSeq whole transcriptome protocols respectively. Specifically for lincRNAs, we observed superb Pearson correlation (0.988) between matched fresh-frozen and FFPE pairs. FFPE samples across NanoString and RNA-Seq platforms gave a mean Pearson correlation of 0.838. In FFPE libraries, we detected 53.4% of high confidence SNVs and 24% of high confidence fusion transcripts. Sensitivity of fusion transcript detection was not overcome by an increase in depth of sequencing up to 3-fold (increase from ~56 to ~159 million reads). Both NanoString and ScriptSeq RNA-Seq technologies yield reliable gene expression data for degraded and FFPE material. The high degree of correlation between NanoString and RNA-Seq platforms suggests discovery based whole transciptome studies from FFPE material will produce reliable expression data. The RiboZeroGold ScriptSeq protocol performed particularly well for lincRNA expression from FFPE libraries but detection of eSNV and fusion transcripts was less sensitive. Overall design: We performed RNASeq on RNA from nine matched pairs of fresh-frozen and FFPE tissues from breast cancer patients. The goal was to test the RiboZeroGold ScriptSeq complete low input library preparation kit for degraded RNA samples.
Gene expression, single nucleotide variant and fusion transcript discovery in archival material from breast tumors.
No sample metadata fields
View SamplesMice lacking the transcription factor Fezf1 exhibit defects in the structural and molecular organiztion of their olfactory system. To invetigate this at the level of gene expression, we isolated Fezf1 expressing cells by FACS from the MOE of Fezf1+/- or Fezf1-/- animals and compared their gene expression profiles.
Fezf1 and Fezf2 are required for olfactory development and sensory neuron identity.
Specimen part
View SamplesDisruption of peripheral circadian rhyme pathways dominantly leads to metabolic disorders. Studies on circadian rhythm proteins in the heart indicated a role for Clock or Per2 in cardiac metabolism. In fact, Per2-/- mice have larger infarct sizes with a deficient lactate production during myocardial ischemia. To test the hypothesis that cardiac Per2 represents an important regulator of cardiac metabolism during myocardial ischemia, we performed lactate measurements during reperfusion in Per1-/-, Per2-/- or wildtype mice followed by gene array studies using various ischemia-reperfusion protocols comparing wildtype and Per2-/- mice. Lactate measurements in whole blood confirmed a dominant role of Per2 for lactate production during myocardial ischemia. Surprisingly, high-throughput gene array analysis of eight different conditions on one 24-microarray plate revealed dominantly lipid metabolism as differentially regulated pathway in wildtype mice when compared to Per2-/-. In all treatment groups, the enzyme enoyl-CoA hydratase, which is essential in fatty acid beta-oxidation, was regulated in wildtype animals only. Studies using nuclear magnet resonance imaging (NMRI) confirmed altered fatty acid populations with higher mono-unsaturated fatty acid levels in hearts from Per2-/- mice. Unexpectedly, studies on gene regulation during reperfusion revealed solely pro inflammatory genes as differentially regulated 'Per2-genes'. Subsequent studies on inflammatory markers showed increasing IL6 or TNFa levels during reperfusion in Per2-/- mice. In summary, these studies reveal a novel role of cardiac Per2 for fatty acid metabolism or inflammation during myocardial ischemia and reperfusion.
Cardiac Per2 functions as novel link between fatty acid metabolism and myocardial inflammation during ischemia and reperfusion injury of the heart.
Sex, Specimen part
View SamplesVentilator induced lung injury can lead to serious conditions like ARDS which are associated with a high mortality (around 30%, Stapleton et al., Chest, 2005). We hypothesized that changes of expression levels of different genes would lead us to the identification of critical target genes, which might influence the inflammation and outcome associated with this condition.
HIF1A reduces acute lung injury by optimizing carbohydrate metabolism in the alveolar epithelium.
Disease, Cell line, Treatment
View SamplesA complex interplay between ethylene, ETP1/ETP2 F-box proteins, and degradation of EIN2 is essential for triggering ethylene responses in plants.
Interplay between ethylene, ETP1/ETP2 F-box proteins, and degradation of EIN2 triggers ethylene responses in Arabidopsis.
Age, Treatment
View SamplesChronic low dose inorganic arsenic (iAs) exposure leads to changes in gene expression and epithelial-to-mesenchymal transformation. During this transformation, cells adopt a fibroblast-like phenotype accompanied by profound gene expression changes. While many mechanisms have been implicated in this transformation, studies that focus on the role of epigenetic alterations in this process are just emerging. DNA methylation controls gene expression in physiologic and pathologic states. Several studies show alterations in DNA methylation patterns in iAs-mediated pathogenesis, but these studies focused on single genes. We present a comprehensive genome-wide DNA methylation analysis using methyl-sequencing to measure changes between normal and iAs-transformed cells. Additionally, these differential methylation changes correlated positively with changes in gene expression and alternative splicing. Interestingly, most of these differentially methylated genes function in cell adhesion and communication pathways. To gain insight into how genomic DNA methylation patterns are regulated iAs-mediated carcinogenesis, we show that iAs probably targets CTCF binding at the promoter of DNA methyltransferases, regulating their expression. These findings reveal how transcription factor binding regulates DNA methyltransferase to reprogram the methylome in response to an environmental toxin.
Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation.
Specimen part, Cell line, Treatment
View SamplesBoth cigarette smoking and obesity have been implicated in increased risk of clear cell renal cell carcinoma (ccRCC); however, there are limited data regarding the molecular mechanisms that underlie these associations. We used a multi-stage design to identify and validate specific molecular targets that are associated with smoking or obesity-related ccRCC.
ANKS1B is a smoking-related molecular alteration in clear cell renal cell carcinoma.
Specimen part, Subject
View Samples