Filters
Technology
Platform
GSE39676
Mus musculus
12 Downloadable Samples
Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Geminin is a small nucleoprotein that neuralizes ectoderm in the Xenopus embryo. Geminin promotes neural fate acquisition of mouse embryonic stem cells: Geminin knockdown during neural fate acquisition decreased expression of neural precursor cell markers (Pax6, Sox1), while increasing expression of Pitx2, Lefty1 and Cited2, genes involved in formation of the mouse node. Here we differentiated mouse embryonic stem cells into embryoid bodies to study Geminin's ability to repress primitive streak mesendoderm fate acquisition. We used microarrays to define the sets of genes that are regulated by Geminin during cell fate acquisition in embryoid bodies, using Dox-inducible Geminin knockdown or overexpression mouse embryonic stem cell lines.
Publication Title
Geminin restrains mesendodermal fate acquisition of embryonic stem cells and is associated with antagonism of Wnt signaling and enhanced polycomb-mediated repression.
Sample Metadata Fields
Specimen part
View Samples- Xenopus laevis
- 12 Downloadable Samples
- Affymetrix Xenopus laevis Genome Array (xenopuslaevis)
Description
Geminin cooperates with Polycomb to restrain multi-lineage commitment in the early embryo: Transient maintenance of a pluripotent embryonic cell population followed by the onset of multi-lineage commitment is a fundamental aspect of development. However, molecular regulation of this transition is not well characterized in vivo. Here we demonstrate that the nuclear protein Geminin is required to restrain commitment and spatially restrict mesoderm, endoderm, and non-neural ectoderm to their proper locations in the Xenopus embryo. We used microarray analyses to demonstrate that Geminin overexpression represses many genes associated with cell commitment and differentiation, while elevating expression levels of genes that maintain pluripotent early and immature neurectodermal cell states. We characterized Geminins relationship to cell signaling and found that Geminin broadly represses Activin-, FGF-, and BMP-mediated cell commitment. Conversely, Geminin knockdown enhances commitment responses to growth factor signaling and causes ectopic mesodermal, endodermal, and epidermal fate commitment in the embryo. We also characterized Geminins functional relationship with transcription factors that had similar activities and found that Geminin represses commitment independent of Oct4 ortholog (Oct25/60) activities, but depends upon intact Polycomb repressor function. Consistent with this, chromatin immunoprecipitation assays directed at mesodermal genes demonstrate that Geminin promotes Polycomb binding and Polycomb-mediated repressive histone modifications, while inhibiting modifications associated with gene activation. This work defines Geminin as an essential regulator of the embryonic transition from pluripotency through early multi-lineage commitment, and demonstrates that functional cooperativity between Geminin and Polycomb contributes to this process.
Publication Title
Geminin cooperates with Polycomb to restrain multi-lineage commitment in the early embryo.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 6 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Formation of the complex vertebrate nervous system begins when pluripotent cells of the early embryo are directed to acquire a neural fate. Although cell intrinsic controls play an important role in this process, the molecular nature of this regulation is not well defined. Here we assessed the role for Geminin, a nuclear protein expressed in embryonic cells, in neural fate acquisition from mouse embryonic stem (ES) cells. While Geminin knockdown does not affect the ability of ES cells to maintain or exit pluripotency, we found that it significantly impairs their ability to acquire a neural fate. Conversely, Geminin overexpression promotes neural gene expression, even in the presence of growth factor signaling that antagonizes neural transcriptional responses. These data demonstrate that Geminins activity contributes to mammalian neural cell fate acquisition. We investigated the mechanistic basis of this phenomenon and found that Geminin maintains a hyperacetylated and open chromatin conformation at neural genes. Interestingly, recombinant Geminin protein also rapidly alters chromatin acetylation and accessibility even when Geminin is combined with nuclear extract and chromatin in vitro. These findings define a novel activity for Geminin in regulation of chromatin structure. Together, these data support a role for Geminin as a cell intrinsic regulator of neural fate acquisition that promotes expression of neural genes by regulating chromatin accessibility and histone acetylation.
Publication Title
Geminin promotes neural fate acquisition of embryonic stem cells by maintaining chromatin in an accessible and hyperacetylated state.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Homo sapiens
- 8 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Extracts from the rhizome of Cimicifuga racemosa (black cohosh) are increasingly popular as herbal alternative to hormone replacement therapy (HRT) for the alleviation of postmenopausal disorders. However, the molecular mode of action and the active principles are presently not clear. Previously published data have been largely contradictory. We, therefore, investigated the effects of a lipophilic Cimicifuga rhizome extract on the ER+ breast cancer MCF-7 cells at transcriptional level in comparision to 17beta-estradiol and the ER antagonist tamoxifen. With the extract 431 genes were regulated more than 1.5 fold. The overall expression pattern differed from those of 17-estradiol or the estrogen receptor antagonist tamoxifen. We observed an enrichment of genes in an anti-proliferative and apoptosis-sensitizing manner, together with an increase of mRNAs coding for gene products involved in several stress response pathways. Regulated genes of these functional groups were highly overrepresented among all regulated genes. Various transcripts coding for oxidoreductases were induced, as for example the cytochrome P450 family members 1A1 and 1B1. In addition, some transcripts associated with antitumor but also tumor-promoting activity were regulated.
Publication Title
Gene expression profiling reveals effects of Cimicifuga racemosa (L.) NUTT. (black cohosh) on the estrogen receptor positive human breast cancer cell line MCF-7.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 29 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
High quality genetic material is an essential pre-requisite when analyzing gene expression using microarray technology. Peripheral blood mononuclear cells (PBMC) are frequently used for genomic analyses, but several factors can affect the integrity of nucleic acids prior to their extraction, including the methods of PBMC collection and isolation. In this study, we compared the Ficoll-Paque density gradient centrifugation and BD Vacutainer cell preparation tube (CPT) protocols to determine if either method offered a distinct advantage in preparation of PBMC-derived immune cell subsets for their use in gene expression analysis. We compared gene expression in PBMC and individual immune cell types from Ficoll and CPT isolation protocols using Affymetrix microarrays.
Publication Title
Immune cell subsets and their gene expression profiles from human PBMC isolated by Vacutainer Cell Preparation Tube (CPT™) and standard density gradient.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus, Xenopus laevis
- 6 Downloadable Samples
- Affymetrix Xenopus laevis Genome Array (xenopuslaevis)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Geminin regulates the transcriptional and epigenetic status of neuronal fate-promoting genes during mammalian neurogenesis.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Xenopus laevis
- 6 Downloadable Samples
- Affymetrix Xenopus laevis Genome Array (xenopuslaevis)
Description
Transcriptional targets of neurogenin (Ngnr1) were identified by over-expression of an inducible form of neurogenin in Xenopus ectodermal explants. The effects of co-expressing the nucleoprotein geminin on Ngnr1-dependent target gene transactivation were defined.
Publication Title
Geminin regulates the transcriptional and epigenetic status of neuronal fate-promoting genes during mammalian neurogenesis.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Mus musculus
- 4 Downloadable Samples
Illumina HiSeq 2000
Description
Regulating the transition from lineage-restricted progenitors to terminally differentiated cells is a central aspect of nervous system development. Here, we investigated the role of the nucleoprotein Geminin in regulating neurogenesis at a mechanistic level during both Xenopus primary neurogenesis and mammalian neuronal differentiation in vitro. The latter work utilized both neural cells derived from embryonic stem and embryonal carcinoma cells in vitro and neural stem cells from mouse forebrain. In all of these contexts, Geminin antagonized the ability of neural bHLH transcription factors to activate transcriptional programs promoting neurogenesis. Furthermore, Geminin promoted a bivalent chromatin state, characterized by the presence of both activating and repressive histone modifications, at genes encoding transcription factors that promote neurogenesis. This epigenetic state restrains the expression of genes that regulate commitment of undifferentiated stem and neuronal precursor cells to neuronal lineages. Geminin is highly expressed in undifferentiated neuronal precursor cells but is downregulated prior to differentiation. Therefore, these data support a model whereby Geminin promotes the neuronal precursor cell state by modulating both the epigenetic status and expression of genes encoding neurogenesis-promoting factors. Additional developmental signals acting in these cells can then control their transition toward terminal neuronal or glial differentiation during mammalian neurogenesis. Overall design: A mouse embryonic stem (ES) cell line for inducible knockdown of the small nucleoprotein Geminin was utilized. ES cells were used to generate neural precursor cells by monolayer culture in N2B27 media for 5 days, and doxycycline-inducible knockdown of Geminin was performed from day 3. Changes in gene expression resulting from Geminin knockdown were assessed by RNA sequencing. Three experimental replicates were generated for Geminin knockdown (plus Dox) with a corresponding no-Dox control. These were subjected to sequencing, and data were analyzed using TopHat and Cufflinks/Cuffdiff. Transcripts were considered as differentially expressed upon Gem knockdown if data met statistical significance cutoffs in Cuffdiff (sufficient sequence alignments were obtained for analysis and transcript had significant change in FPKM value (normalized transcript abundance; fragments per kb of exon per million fragments mapped) between the no Dox and plus Dox sample pairs) in at least two of the three replicates.
Publication Title
Geminin regulates the transcriptional and epigenetic status of neuronal fate-promoting genes during mammalian neurogenesis.
Sample Metadata Fields
Specimen part, Treatment, Subject
View Samples- Homo sapiens
- 8 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Products derived from roots of Leuzea carthamoides DC. (maral root) are being promoted as anti-aging and adaptogenic. The phytoecdysteroids are considered as active principles with numerous beneficial effects, but little is known about the pharmacological properties of Leuzea extracts. We, therefore, investigated the effects of a lipophilic Leuzea root extract on ER+ breast cancer MCF-7 cells at transcriptional level in comparison to 17beta-estradiol and the ER antagonist tamoxifen. With the extract 241 genes were regulated more than 1.5 fold. We observed gene regulation in an anti-proliferative and pro-apoptotic manner.
Publication Title
Effects of Leuzea carthamoides on human breast adenocarcinoma MCF-7 cells determined by gene expression profiling and functional assays.
Sample Metadata Fields
No sample metadata fields
View Samples- Saccharomyces cerevisiae
- 26 Downloadable Samples
- Affymetrix Yeast Genome 2.0 Array (yeast2)
Description
Studies using yeast have advanced our understanding of both replicative and chronological aging, leading to the discovery of longevity genes that have homologues in higher eukaryotes. Chronological lifespan in yeast is conventionally defined as the lifespan of a non-dividing cell. To date, this parameter has only been estimated under calorically restricted (CR) conditions, mimicked by starvation. Since post-mitotic cells in higher eukaryotes are rarely calorically-restricted, we sought to develop an alternative experimental system where non-dividing yeast would age chronologically, in the presence of excess nutrients. We report here on a system wherein alginate-encapsulated yeast are packed in a pH- and temperature-controlled bioreactor, then continuously fed non-limiting substrate for extended periods of time. We present demographic, physiological and genomic evidence indicating that after ~120 hrs, immobilized cells cease dividing, remain metabolically very active and retain >95% viability for periods of 17 days. Over the same time interval, starved planktonic cells, cultured using the same media, and also controlled for temperature and pH, retained < 1 % viability in both aerobic and anaerobic cultures,. Unlike planktonic yeast, continuously-fed immobilized cells hyper-accumulate glycogen. FACS analysis of SYTOX green-stained yeast confirms that immobilized cells completely arrest within 5 days of culture, and unlike starving planktonic cells, remain free thereafter of replicative stress and are non-apoptotic. This unusual state is supported by a global gene expression profile that is stable over time, repeatable across replicate experiments, and altogether distinct from planktonic cells cultured in the presence and absence of limiting nutrients. DNA expression profiling, performed here for the very first time on immobilized cells, reveals that glycolytic genes and their trans-acting regulatory elements are upregulated, as are genes involved in remodeling the cell wall and resisting stress; by contrast, many genes that promote cell cycle progression and carry out oxidative metabolism are repressed. Stress resistance transcription factor MSN4 and its upstream effector RIM15 are conspicuously upregulated in the immobilized state, suggesting that nutrient-sensing pathways may play a role in cell viability and longevity when yeast are immobilized and placed in prolonged culture under calorically-unrestricted conditions. The cell cycle arrest in the immobilized state is mediated by RIM 15. Over the time-course of our experiments, well-fed, non-diving immobilized cells do not appear to age.
Publication Title
Uncoupling reproduction from metabolism extends chronological lifespan in yeast.
Sample Metadata Fields
No sample metadata fields
View Samples