Primary cells enter replicative senescence after a limited number of cell divisions. This process is associated with reproducible changes in DNA methylation (DNAm) at specific sites in the genome. The mechanism that drives senescence-associated DNAm changes remains unknown and may arise through drift in DNAm or through regulated, senescence dependent modifications at specific sites in the genome. In this study, we analyzed the reorganization of nuclear architecture and DNA methylation during long-term culture of human fibroblasts and mesenchymal stromal cells (MSCs). [RNA-seq] Overall design: RNA was isolated from 1,000,000 cells of three MSC donors (59, 64, and 73 years old) at passage 4 and passage 13 using the miRNeasy Mini Kit (Qiagen). Gene expression profiles were analzyed by deep sequencing with IlluminaHiSeq 2000 technology with a read length of 50 bases at EMBL gene core facility (Heidelberg, Germany).
Replicative senescence is associated with nuclear reorganization and with DNA methylation at specific transcription factor binding sites.
No sample metadata fields
View SamplesHow spatial chromosome organization influences genome integrity is still poorly understood. Here we show that DNA double-strand breaks (DSBs) mediated by topoisomerase 2 (TOP2) activities, are enriched at chromatin loop anchors with high transcriptional activity. Recurrent DSBs occur at CTCF/cohesin bound sites at the bases of chromatin loops and their frequency positively correlates with transcriptional output and directionality. The physiological relevance of this preferential positioning is indicated by the finding that genes recurrently translocating to drive leukemias, are highly transcribed and are enriched at loop anchors. These genes accumulate DSBs at recurrent hot spots that give rise to chromosomal fusions relying on the activity of both TOP2 isoforms and on transcriptional elongation. We propose that transcription and 3D chromosome folding jointly pose a threat to genomic stability, and are key contributors to the occurrence of genome rearrangements that drive cancer. Overall design: Nuclear RNA profiling in lymphoblastoid TK6 cell line
Spatial Chromosome Folding and Active Transcription Drive DNA Fragility and Formation of Oncogenic MLL Translocations.
Specimen part, Cell line, Subject
View SamplesInflorescence stages 1 to 12 from mutants involved in Arabidopsis small RNA metabolism. Three biological replicates of each mutant comprising at least 9 independent plants were harvested, and the expression profiles were determined using Affymetrix ATH1 arrays. Comparisons among the sample groups allow the identification of genes regulated by small RNAs (microRNAs and siRNAs).
microRNA-directed phasing during trans-acting siRNA biogenesis in plants.
No sample metadata fields
View SamplesEstrogen signaling and epigenetic modifications, in particular DNA methylation, are involved in regulation of gene expression in breast cancers. Here we investigated a potential regulatory cross-talk between these two pathways by identifying their common target genes and exploring potential underlying molecular mechanisms in human MCF7 breast cancer cells. Principal Findings: Gene expression profiling revealed that the expression of approximately 150 genes was influenced by both 17-estradiol (E2) and a hypomethylating agent 5-aza-2-deoxycytidine (DAC). Based on gene ontology (GO), CpG island prediction analysis and previously reported estrogen receptor (ER) binding regions, we selected six genes for further analysis (BTG3, FHL2, PMAIP1, BTG2, CDKN1A and TGFB2). GO analysis suggests that these genes are involved in intracellular signaling cascades, regulation of cell proliferation and apoptosis, while CpG island prediction of promoter regions reveals that the promoters of these genes contain at least one CpG island. Using chromatin immunoprecipitation, we show that ER is recruited to CpG islands in promoters, but neither in an E2- nor in a DAC-dependent fashion. DAC treatment reactivates the expression of all selected genes although only the promoters of BTG3 and FHL2 genes are methylated, with E2 treatment showing no effect on the methylation status of these promoters. Conclusions: We identified a set of genes regulated by both estrogen signaling and DNA methylation. However, our data does not support a direct molecular interplay of mediators of estrogen and epigenetic signaling at promoters of regulated genes.
Global identification of genes regulated by estrogen signaling and demethylation in MCF-7 breast cancer cells.
Cell line
View SamplesAcute quadriplegic myopathy (AQM) or critical illness myopathy (CIM) is frequently observed in intensive care unit (ICU) patients. In order to elucidate duration-dependent effects of the ICU intervention on molecular and functional networks that control the muscle wasting and weakness in AQM, gene expression profile was analyzed at time points varying from 6 hours to 14 days in a unique experimental rat model mimicking ICU conditions, i.e., post-synaptically paralyzed, mechanically ventilated and extensively monitored animals.
Muscle wasting and the temporal gene expression pattern in a novel rat intensive care unit model.
Sex, Specimen part, Disease, Disease stage
View Samples10 male subjects performed ~45 min one-legged cycling and 4 x 7 maximal concentric-eccentric knee extensions for each leg 15 min later. Thus, one limb performed aerobic and resistance exercise (AE+RE), while the opposing leg did resistance exercise only (RE). Biopsies were obtained from m. vastus lateralis of each leg 3 h after the resistance exercise bout.
Aerobic exercise augments muscle transcriptome profile of resistance exercise.
Sex, Specimen part, Treatment, Subject
View SamplesMitotic entry is accompanyed by the expression of a cluster of so called mitotic genes, whose activation is critical for mitosis in human and yeast cells. We found a link between the transcription machinery and cell cycle control network at mitosis in fission yeast, involving the Cdk8 kinase dependent phosphorylation of the fork head transcription factor Fkh2. We have generated a non-phosphorylatable fkh2 mutant (fkh2-S2A) also.
Cyclin-dependent kinase 8 regulates mitotic commitment in fission yeast.
No sample metadata fields
View SamplesDrugMatrix is a comprehensive rat toxicogenomics database and analysis tool developed to facilitate the integration of toxicogenomics into hazard assessment. Using the whole genome and a diverse set of compounds allows a comprehensive view of most pharmacological and toxicological questions and is applicable to other situations such as disease and development.
Genomic models of short-term exposure accurately predict long-term chemical carcinogenicity and identify putative mechanisms of action.
Sex, Specimen part, Compound, Time
View SamplesDrugMatrix is a comprehensive rat toxicogenomics database and analysis tool developed to facilitate the integration of toxicogenomics into hazard assessment. Using the whole genome and a diverse set of compounds allows a comprehensive view of most pharmacological and toxicological questions and is applicable to other situations such as disease and development.
Genomic models of short-term exposure accurately predict long-term chemical carcinogenicity and identify putative mechanisms of action.
Specimen part, Compound, Time
View SamplesDrugMatrix is a comprehensive rat toxicogenomics database and analysis tool developed to facilitate the integration of toxicogenomics into hazard assessment. Using the whole genome and a diverse set of compounds allows a comprehensive view of most pharmacological and toxicological questions and is applicable to other situations such as disease and development.
Genomic models of short-term exposure accurately predict long-term chemical carcinogenicity and identify putative mechanisms of action.
Sex, Specimen part, Compound, Time
View Samples