Naïve and primed pluripotency is characterized by distinct signaling requirements, transcriptomes and developmental properties, but both cellular states share key transcriptional regulators, Oct4, Sox2 and Nanog. Here we demonstrate that transition between these two pluripotent states is associated with widespread Oct4 relocalization, mirrored by global rearrangement of enhancer chromatin landscapes. Our genomic and biochemical analyses identified candidate mediators of primed state-specific Oct4 binding, including Otx2 and Zic2/3. Even in the absence of other differentiation cues, premature Otx2 overexpression is sufficient to exit the naïve state, induce transcription of a large subset of primed pluripotency-associated genes and redirect Oct4 to thousands of previously inaccessible sites. However, ability of Otx2 to engage new enhancer regions is determined by its levels, cis-encoded properties of the sites and signaling environment. Our results illuminate regulatory mechanisms underlying pluripotency and suggest that capacity of transcription factors such as Otx2 and Oct4 to function as pioneers is highly context-dependent Overall design: transcription profile of ESCs and EpiLCs to analzye changes during differentiation and the effect of Otx2 loss and overexpression on the differentiation properties
Reorganization of enhancer patterns in transition from naive to primed pluripotency.
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View SamplesAlzheimer's disease (AD) is a devastating neurodegenerative disorder that threatens to reach epidemic proportions as our population ages. Although much research has examined molecular pathways associated with AD, relatively few studies have focused on critical early stages. Our prior microarray study correlated gene expression in human hippocampus with AD markers. Results suggested a new model of early-stage AD in which pathology spreads along myelinated axons, orchestrated by upregulated transcription and epigenetic factors related to growth and tumor suppression (Blalock et al., 2004). However, the microarray analyses were performed on RNA from fresh frozen hippocampal tissue blocks containing both gray and white matter, potentially obscuring region-specific changes. In the present study, we used laser capture microdissection to exclude major white matter tracts and selectively collect CA1 hippocampal gray matter from formalin-fixed, paraffin-embedded (FFPE) hippoc ampal sections of the same subjects assessed in our prior study. Microarray analyses of this gray matter-enriched tissue revealed many correlations similar to those seen in our prior study, particularly for neuron-related genes. Nonetheless, in the laser-captured tissue, we found a striking paucity of the AD-associated epigenetic and transcription factor genes that had been strongly overrepresented in the prior tissue block study. In addition, we identified novel pathway alterations that may have considerable mechanistic implications, including downregulation of genes stabilizing ryanodine receptor Ca2+ release and upregulation of vascular development genes. We conclude that FFPE tissue can be a reliable resource for microarray studies, that upregulation of growth-related epigenetic/ transcription factors with incipient AD is predominantly localized to white matter, further supporting our prior findings and model, and that alterations in vascular and ryanodine receptor-relat ed pathways in gray matter are closely associated with incipient AD.
Microarray analyses of laser-captured hippocampus reveal distinct gray and white matter signatures associated with incipient Alzheimer's disease.
Sex, Age, Disease
View SamplesBackground: Age-related cognitive deficits negatively affect quality of life and can presage serious neurodegenerative disorders. Despite sleep disruptions well-recognized negative influence on cognition, and its prevalence with age, surprisingly few studies have tested sleeps relationship to cognitive aging.
Deep sleep and parietal cortex gene expression changes are related to cognitive deficits with age.
Sex, Age, Specimen part, Subject
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The oscillating miRNA 959-964 cluster impacts Drosophila feeding time and other circadian outputs.
Specimen part
View SamplesUsing high throughput sequencing of Drosophila head RNA, a small set of miRNAs that undergo robust circadian oscillations in levels were discovered. We concentrated on a cluster of six miRNAs, mir-959-964, all of which peak at about ZT12 or lights-off. The data indicate that the cluster pri-miRNA is transcribed under bona fide circadian transcriptional control and that all 6 mature miRNAs have short half-lives, a requirement for oscillating. Manipulation of food intake dramatically affects the levels and timing of cluster miRNA transcription with no more than minor effects on the core circadian oscillator. This indicates that the central clock regulates feeding, which in turn regulates proper levels and cycling of the cluster miRNAs. Viable Gal4 knock-in as well as cluster knock-out and over-expression strains were used to localize cluster miRNA expression as well as explore their functions. The adult head fat body is a major site of expression, and feeding behavior, innate immunity, metabolism, and perhaps stress responses are under cluster miRNA regulation. The feeding behavior results indicate that there is a feedback circuit between feeding time and cluster miRNA function as well as a surprising role of post-transcriptional regulation in these behaviors and physiology.
The oscillating miRNA 959-964 cluster impacts Drosophila feeding time and other circadian outputs.
Specimen part
View SamplesComparison of Arabidopsis seedlings with disturbed function of CDKB2;1 and CDKB2;2 by either overexpression or knock-down
Requirement of B2-type cyclin-dependent kinases for meristem integrity in Arabidopsis thaliana.
Specimen part
View SamplesUsing high throughput sequencing of Drosophila head RNA, a small set of miRNAs that undergo robust circadian oscillations in levels were discovered. We concentrated on a cluster of six miRNAs, mir-959-964, all of which peak at about ZT12 or lights-off. The data indicate that the cluster pri-miRNA is transcribed under bona fide circadian transcriptional control and that all 6 mature miRNAs have short half-lives, a requirement for oscillating. Manipulation of food intake dramatically affects the levels and timing of cluster miRNA transcription with no more than minor effects on the core circadian oscillator. This indicates that the central clock regulates feeding, which in turn regulates proper levels and cycling of the cluster miRNAs. Viable Gal4 knock-in as well as cluster knock-out and over-expression strains were used to localize cluster miRNA expression as well as explore their functions. The adult head fat body is a major site of expression, and feeding behavior, innate immunity, metabolism, and perhaps stress responses are under cluster miRNA regulation. The feeding behavior results indicate that there is a feedback circuit between feeding time and cluster miRNA function as well as a surprising role of post-transcriptional regulation in these behaviors and physiology. Overall design: Six samples of small RNA libraries (RNA size 19 to 29 nucleotides long) were prepared from Drosophila heads, each collected at one circadian time point during a light-dark cycle (ZT0, ZT4, ZT8, ZT12, ZT16, ZT20).
The oscillating miRNA 959-964 cluster impacts Drosophila feeding time and other circadian outputs.
Specimen part, Cell line, Subject
View SamplesSleep deprivation (SD) in young adults is associated with metabolic, stress and cognitive responses that are also characteristic of brain aging. Given that sleep architecture changes with age, including increased fragmentation and decreased slow wave activity, it seems reasonable to investigate potential molecular relationships between SD and aging in brain tissue. Here, we tested the hypothesis that young rats exposed to 24 or 72 hour SD would respond with stress and aging-like shifts in brain hippocampal CA1 gene expression. SD animals showed blood corticosterone and weight changes consistent with a stress response. Microarray results, validated by Western blot and comparison to prior SD studies, pointed to disruptions in neurotransmission, sleep pressure signaling, and macromolecular synthesis. In a separate experiment, animals exposed to 24 or 72 hour novel environment stress recapitulated nearly one third of the SD transcriptional profile, particularly upregulated apoptotic and immune signaling pathways. Compared to aging (based on three previously published independent hippocampal aging studies), SD transcriptional profiles agreed for neurogenesis and energy pathways. However, immune signaling, glial activity, macromolecular synthesis and neuronal function all showed an SD profile that was, at least in part, opposed by aging. We conclude that while stress and SD have discrete molecular signatures, they do show a subset of highly similar changes. However, the same could not be said of aging and SD, where a similar subset of genes is changed, but in partially divergent directions. Finally, this work identifies presynaptic vesicular release and intercellular adhesion molecular signatures as novel targets for future SD-countering therapeutics.
Hippocampal CA1 transcriptional profile of sleep deprivation: relation to aging and stress.
Sex, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MYBL2 is a sub-haploinsufficient tumor suppressor gene in myeloid malignancy.
Specimen part, Disease, Disease stage
View SamplesA dosage-dependent role for tumor suppressor genes in the initiation of myeloid malignancies remains controversial. Here we show that MYBL2 is expressed at sharply reduced levels in CD34+ cells from most patients with myelodysplastic syndrome (MDS; 65%; n=26). In a murine competitive reconstitution model, Mybl2 knockdown by RNAi to 20-30% of normal levels in multipotent hematopoietic progenitors led to clonal dominance by these sub-haploinsufficient cells, affecting all blood cell lineages. By 6 months post-transplantation, the reconstituted mice had developed a myeloproliferative/myelodysplastic disorder originating from the cells with aberrantly reduced Mybl2 expression. Thus, downregulation of MYBL2 activity to levels below those predicted by classical haploinsufficiency drives the clonal expansion of hematopoietic progenitors in a large fraction of human MDS cases.
MYBL2 is a sub-haploinsufficient tumor suppressor gene in myeloid malignancy.
Specimen part, Disease, Disease stage
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