Microarray analysis of gene expression after transverse aortic constriction in mice: comparison of TAC vs. sham group at 48 hours, 10 days, and 3 weeks.
Microarray analysis of gene expression after transverse aortic constriction in mice.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reprogramming factor expression initiates widespread targeted chromatin remodeling.
Specimen part
View SamplesDespite rapid progress in characterizing transcription factor-driven reprogramming of somatic cells to an induced pluripotent stem (iPS) cell state, many mechanistic questions still remain. To gain insight into the earliest events in the reprogramming process, we systematically analyzed the transcriptional and epigenetic changes that occur during early factor induction after discrete numbers of divisions. We observed rapid, genome-wide changes in the euchromatic histone modification, H3K4me2, at more than a thousand loci including large subsets of pluripotency or developmentally related gene promoters and enhancers. In contrast, patterns of the repressive H3K27me3 modification remained largely unchanged except for focused depletion specifically at positions where H3K4 methylation is gained. These chromatin regulatory events precede transcriptional changes within the corresponding loci. Our data provide evidence for an early, organized, and population-wide epigenetic response to ectopic reprogramming factors that clarify the temporal order through which somatic identity is reset during reprogramming.
Reprogramming factor expression initiates widespread targeted chromatin remodeling.
Specimen part
View SamplesThe recruitment of mesenchymal stem cells in order to reconstruct damaged cartilage of osteoarthritis joints is a challenging tissue engineering task. Vision towards this goal is blurred by a lack of knowledge about the underlying differences between chondrocytes and MSC during the chondrogenic cultivation process. The aim of this study was to shed light on the differences between chondrocytes and MSC occurring during chondral differentiation through tissue engineering.
Expression pattern differences between osteoarthritic chondrocytes and mesenchymal stem cells during chondrogenic differentiation.
Specimen part
View SamplesIonizing radiation (IR) has long been associated with reduced hematopoietic function and increased malignancies, although the mechanisms behind this relationship remain poorly understood. The carcinogenic effect of IR has been commonly attributed to the direct induction of DNA damage. We demonstrate that IR exposure results in long-term, somatically heritable, cell-intrinsic reductions in HSC self-renewal that is mediated by C/EBPa and reversed by Notch, both of which are associated with human leukemias. Remarkably, restoration of HSC self-renewal prevents selection for C/EBPa loss of function in previously irradiated HSC pools. We propose that environmental insults prompt HSC to initiate a program limiting their self-renewal to prevent damaged HSC from contributing to hematopoiesis. This "programmed mediocrity" is advantageous for the localized insults animals have evolved to deal with, but becomes tumor promoting when the entire HSC compartment is damaged, such as during total body irradiation, by increasing selective pressure for adaptive oncogenic mutations Overall design: Examination of mRNA levels in in vitro and in vivo Hematopoietic Stem Cell that exposed to IR Ionizing radiation (IR) or control. Each group has three replicates.
Contrasting roles for C/EBPα and Notch in irradiation-induced multipotent hematopoietic progenitor cell defects.
No sample metadata fields
View SamplesHuman pluripotent stem cells were differentiated into hematopoietic progenitors, which were then re-specified using defined transcription factors to resemble hematopoietic stem cells (HSC)
Induction of multipotential hematopoietic progenitors from human pluripotent stem cells via respecification of lineage-restricted precursors.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
H3K4 demethylation by Jarid1a and Jarid1b contributes to retinoblastoma-mediated gene silencing during cellular senescence.
Specimen part, Cell line
View SamplesCellular senescence is a tumor-suppressive program that involves chromatin reorganization and specific changes in gene expression that trigger an irreversible cell-cycle arrest. We have examined the effect of suppressing the histone demethylases Jarid1a and Jarid1b on the senescence-associated gene expression signatures.
H3K4 demethylation by Jarid1a and Jarid1b contributes to retinoblastoma-mediated gene silencing during cellular senescence.
Specimen part, Cell line
View SamplesPurpose: To use RNA-Seq analysis of endothelial cell in various Notch1 alllels in order to determine transcrptional differencesas a consequence of Notch dose. Methods: Using a FACS sorting we generated high-throughput RNA-SEQ data of endothelials in various Notch1 alleles during development Results: Notch1 dose can alter gene expression in a subset of endothelial genes Overall design: RNA-Seq was performed on endothelial cells isolated at e9.5 from embryos with various Notch1 alleles including N1+/+, N1+/-, N1+/vg, N112/vg, N112/-
The intracellular domains of Notch1 and Notch2 are functionally equivalent during development and carcinogenesis.
No sample metadata fields
View SamplesPolycomb group (PcG) proteins mediate heritable but reversible silencing of developmental regulator genes by modifying their chromatin configuration. Accumulating evidence documents a role for PcG proteins in regulating higher order chromatin structures likely by their clustering, however, underlying mechanisms and its impact on transcriptional regulation remain obscure. In this study, we found that subnuclear clustering of PRC1 at canonical PcG target genes depended on head-to-tail polymerization property of SAM domain of Phc2 and likely Phc1. We show that Phc2-SAM polymerization limits the dynamic nature of PRC1, thereby promotes stable association of PRC1 with PcG target genes and contributes to their robust silencing. Our findings suggest a novel model by which SAM polymerization of Phc2 modulates the structural organization of PcG complexes to enable robust yet reversible PcG-mediated repression during development.
SAM domain polymerization links subnuclear clustering of PRC1 to gene silencing.
Specimen part, Disease
View Samples