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GSE21595
Mus musculus
18 Downloadable Samples
Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Induced pluripotent stem (iPS) cell reprogramming is a gradual epigenetic process that reactivates the pluripotent transcriptional network by erasing and establishing heterochromatin marks. Here, we characterize the physical structure of heterochromatin domains in full and partial mouse iPS cells by correlative Electron Spectroscopic Imaging (ESI). In somatic and partial iPS cells, constitutive heterochromatin marked by H3K9me3 is highly compartmentalized into chromocenter structures of densely packed 10 nm chromatin fibers. In contrast, chromocenter boundaries are poorly defined in pluripotent ES and full iPS cells, and are characterized by unusually dispersed 10 nm heterochromatin fibers in high Nanog-expressing cells, including pluripotent cells of the mouse blastocyst prior to differentiation. This heterochromatin reorganization accompanies retroviral silencing during conversion of partial iPS cells by Mek/Gsk3 2i inhibitor treatment. Thus, constitutive heterochromatin reorganization serves as a novel biomarker with retroviral silencing for identifying iPS cells in the very late stages of reprogramming.
Publication Title
Constitutive heterochromatin reorganization during somatic cell reprogramming.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Homo sapiens
- 1 Downloadable Sample
- Illumina HumanHT-12 V3.0 expression beadchip
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sample Metadata Fields
Sex, Cell line, Treatment
View Samples- Homo sapiens
- 1 Downloadable Sample
- Illumina HumanHT-12 V3.0 expression beadchip
Description
The expansion of repressive epigenetic marks has been implicated in heterochromatin formation during embryonic development, but the general applicability of this mechanism is unclear. Here we show that nuclear rearrangement of repressive histone marks H3K9me3 and H3K27me3 into non-overlapping structural layers characterizes senescence-associated heterochromatic foci (SAHF) formation in human fibroblasts. However, the global landscape of these repressive marks remains unchanged upon SAHF formation, suggesting that in somatic cells heterochromatin can be formed through the spatial repositioning of pre-existing repressively marked histones. This model is reinforced by the correlation of pre-senescent replication timing with both the subsequent layered structure of SAHFs and the global landscape of the repressive marks, allowing us to integrate microscopic and genomic information. Furthermore, modulation of SAHF structure does not affect the occupancy of these repressive marks nor vice versa. These experiments reveal that high-order heterochromatin formation and epigenetic remodeling of the genome can be discrete events.
Publication Title
Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sample Metadata Fields
Sex, Cell line, Treatment
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Transcriptome Array 2.0 (hta20)
Description
Mutations in the histone 3 variant H3.3 have been identified in one-third of pediatric glioblastomas (GBMs), but not in adult tumors. Here we show that H3.3 is a dynamic determinant of functional properties in adult GBM. H3.3 is repressed by mixed lineage leukemia 5 (MLL5) in self-renewing GBM cells. MLL5 is a global epigenetic repressor that orchestrates reorganization of chromatin structure by punctuating chromosomes with foci of compacted chromatin, favoring tumorigenic and self-renewing properties. Conversely, H3.3 antagonizes self-renewal and promotes differentiation. We exploited these epigenetic states to rationally identify two small molecules that effectively curb cancer stem cell properties in a preclinical model. Our work uncovers a role for MLL5 and H3.3 in maintaining self-renewal hierarchies in adult GBM.
Publication Title
MLL5 Orchestrates a Cancer Self-Renewal State by Repressing the Histone Variant H3.3 and Globally Reorganizing Chromatin.
Sample Metadata Fields
Specimen part, Time
View Samples- Bos taurus
- 78 Downloadable Samples
- Affymetrix Bovine Genome Array (bovine)
Description
An increase in circulating progesterone (P4) concentrations is associated with increased pregnancy success in beef and dairy cattle. Our objective was to ascertain differential effects of elevated P4 concentrations following conception on endometrial gene expression in beef heifers on Days 5, 7, 13 and 16 of pregnancy, corresponding to the morula, blastocyst, elongation and maternal recognition of pregnancy stages, respectively. Estrus was synchronized in beef heifers (N=263). Two-thirds (N=140) were inseminated (Day 0), and all animals were randomly assigned to one of the following treatments: (i) pregnant, high P4; (ii) pregnant, normal P4; (iii) cycling, high P4; (iv) and cycling, normal P4. All high P4 groups received a P4 release intravaginal device (PRID) on Day 3 post-estrus/mating. Tissue was collected on Days 5, 7, 13 or 16 of the cycle or pregnancy, and pregnancy was confirmed by the presence of an appropriately developed embryo/conceptus. PRID insertion elevated (P<0.05) P4 concentrations from Day 3.5 to 8 compared with untreated animals and conceptus size was larger (P<0.05) in animals with elevated P4 on Days 13 and 16 compared with normal P4. Total RNA was extracted from predominantly intercaruncular endometria from the ipsilateral uterine horn. Samples from individual heifers were selected on the basis of their P4 profiles and gene expression was analyzed using bovine Affymetrix microarrays (N=5 per treatment per time point). Microarray data from analyses using Bioconductor GCRMA and Limma packages were subjected to a modified t-test and P-values were adjusted for multiple testing using the Benjamin and Hochberg false discovery rate method. Differentially expressed genes were selected on the basis of an adjusted P-value of <0.01. There were no detectable differences in gene expression in endometria from pregnant and cyclic heifers on Days 5, 7 and 13 post-estrus, but, the expression of 764 genes was altered due to the presence of the conceptus at maternal recognition of pregnancy (Day 16). On Days 5 and 7, elevated P4 in pregnant heifers, altered the expression of 36 and 124 genes respectively but on Days 13 and 16 there were relatively few DEG between high and normal P4 heifers (15 and 25). Of the genes that were differentially regulated by P4, the majority were unique to a specific day of the estrous cycle/early pregnancy. In conclusion, gene expression in endometria did not differ between pregnant and cycling heifers until Day 16 of pregnancy (i.e. the time of maternal recognition of pregnancy and production of interferon tau by conceptus trophectoderm); however, elevating P4 in early pregnancy programmed changes in gene expression in endometria that are hypothesized to impact early conceptus growth and development. Thus, on Days 5, 7 and 13 differential gene expression was affected by P4, but on Day 16 the conceptus primarily influenced gene expression in uterine endometria of heifers.
Publication Title
Conceptus-induced changes in the endometrial transcriptome: how soon does the cow know she is pregnant?
Sample Metadata Fields
Specimen part, Time
View Samples- Danio rerio
- 622 Downloadable Samples
IlluminaHiSeq2000
Description
Identification of the coding elements in the genome is a fundamental step to understanding the building blocks of living systems. Short peptides (< 100 aa) have emerged as important regulators of development and physiology, but their identification has been limited by their size. We have leveraged the periodicity of ribosome movement on the mRNA to define actively translated ORFs by ribosome footprinting. This approach identifies several hundred translated small ORFs in zebrafish and human. Computational prediction of small ORFs from codon conservation patterns corroborates and extends these findings and identifies conserved sequences in zebrafish and human, suggesting functional peptide products (micropeptides). These results identify micropeptide-encoding genes in vertebrates, providing an entry point to define their function in vivo. Overall design: Ribosome profiling experiments at five timepoints across zebrafish development in WT embryos
Publication Title
Upstream ORFs are prevalent translational repressors in vertebrates.
Sample Metadata Fields
No sample metadata fields
View Samples- Danio rerio
- 44 Downloadable Samples
- IlluminaGenomeAnalyzerII
Description
MicroRNAs regulate gene expression through deadenylation, repression and mRNA decay. However, the contribution of each mechanism in non-steady-state situations remains unclear. We monitored the impact of miR-430 on ribosome occupancy of endogenous mRNAs in wild type and dicer mutants lacking mature miR-430. Our results indicate that miR-430 reduces the number of ribosomes on target mRNAs before causing mRNA decay. Translational repression occurs before complete deadenylation, and disrupting deadenylation using an internal poly(A) tail did not block target repression. Finally, we observe that ribosome density along the length of the target mRNA remains constant, suggesting that translational repression occurs by reducing the initiation rate rather than reducing elongation or causing ribosomal drop-off. In summary, our results show that miR-430 regulates translation initiation before inducing mRNA decay. Overall design: Time course parallel ribosome profiling and input mRNA quantification in wildtype and MZdicer mutant embryos
Publication Title
Ribosome profiling shows that miR-430 reduces translation before causing mRNA decay in zebrafish.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Human multipotent stromal cells readily form single-cell-derived colonies when plated at clonal densities. However, the colonies are heterogeneous because cells from a colony form new colonies that vary in size and differentiation potential when replated at clonal densities. The experiments here tested the hypothesis that cells in the inner regions of colonies are partially differentiated, but the differentiation is reversible. Cells were separately isolated from the dense inner (IN) regions and less-dense outer regions (OUT) of single-cell-derived colonies. Cells were then compared by assays of their transcriptomes and proteins, and for clonogenicity and differentiation. IN cells expressed fewer cell-cycle genes and higher levels of genes for extracellular matrix than the OUT cells. When transferred to differentiation medium, differentiation of the colonies occurred primarily in the IN regions. However, the IN cells were indistinguishable from OUT cells when replated at clonal densities and assayed for rates of propagation and clonogenicity. Also, colonies formed by IN cells were similar to colonies formed by OUT cells because they had distinct IN and OUT regions. Cultures of IN and OUT cells remained indistinguishable through multiple passages (30-75 population doublings), and both cells formed colonies that were looser and less dense as they were expanded. The results demonstrated that cells in the IN region of single-cell-derived colonies are partially differentiated, but the differentiation can be reversed by replating the cells at clonal densities.
Publication Title
Reversible commitment to differentiation by human multipotent stromal cells in single-cell-derived colonies.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 24 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
To identify the activity-induced gene expression programs in inhibitory and excitatory neurons, we analyzed RNA extracted from cultured E14 mouse MGE- and CTX-derived neurons (DIV 10) after these cultures were membrane-depolarized for 0, 1 and 6 hrs with 55mM extracellular KCl. To identify the gene programs regulated in these cells by the activity-induced early-response transcription factor Npas4, we repeated the same experiment in the MGE- and CTX-cultures lacking Npas4 (Npas4-KO).
Publication Title
Npas4 regulates excitatory-inhibitory balance within neural circuits through cell-type-specific gene programs.
Sample Metadata Fields
Specimen part, Treatment, Time
View Samples- Mus musculus
- 34 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
The mature CNS contains PDGFRA+ oligodendrocyte progenitor cells (OPC) which may remain quiescent, proliferate, or differentiate into oligodendrocytes. In human gliomas, rapidly proliferating Olig2+ cells resembling OPCs are frequently observed. We sought to identify, in vivo, candidate pathways uniquely required for OPC differentiation or quiescence. Using the bacTRAP methodology, we generated and analyzed mouse lines for translational profiling the major cells types (including OPCs), in the normal mouse brain. We then profiled oligodendoglial (Olig2+) cells from a mouse model of Pdgf-driven glioma. This analysis confirmed that Olig2+ tumor cells are most similar to OPCs, yet, it identified differences in key progenitor genes - candidates for promotion of differentiation or quiescence.
Publication Title
Candidate pathways for promoting differentiation or quiescence of oligodendrocyte progenitor-like cells in glioma.
Sample Metadata Fields
Specimen part
View Samples