Seed dormancy is the inability for seeds to germinate even under favorable conditions. In the Arabidopsis Landsberg <i>erecta</i> (L<i>er</i>) ecotype, 2 weeks of dry storage, called after-ripening, is sufficient to relieve seed dormancy. Such seed is referred to as after-ripened (AR) and has a high rate of germination when imbibed. While widespread transcriptome changes have been previously observed with seed dormancy loss, this experiment was designed to characterize transcriptional changes associated with the increased seed dormancy and dormancy loss of the gibberellin (GA) hormone-insensitive <i>sleepy1-2</i> (<i>sly1-2</i>) mutant. The <i>SLY1</i> gene encodes the F-box subunit of an SCF E3 ubiquitin ligase needed for GA-triggered proteolysis of DELLA repressors of seed germination. In the <i>sly1-2</i> mutant, GA-directed DELLA proteolysis cannot occur leading to DELLA protein accumulation and increased dormancy. <i>sly1-2</i> mutant seeds are fully dormant at 2 weeks of dry storage (0% germination), but germinate well with very long after-ripening (51% germination after 19 months). <i>sly1-2</i> seed germination can also be rescued by overexpression of the GA receptor, <i>GA-INSENSITIVE DWARF1b</i> (<i>GID1b-OE</i>), which resulted in 74% germination at 2 weeks of dry storage. In this experiment, we compared seeds of wild-type L<i>er</i> at 2 weeks of dry storage (non-dormant), dormant <i>sly1-2</i> (2 weeks of dry storage; <i>sly1-2</i>(D)), long after-ripened <i>sly1-2</i> (non-dormant, 19 months of dry storage; <i>sly1-2</i>(AR)), and <i>sly1-2 GID1b-OE</i> (non-dormant, 2 weeks of dry storage). Samples were collected at two imbibition timepoints: 1) a 0h timepoint after 4 days at 4°C, and 2) a 12h timepoint after 4 days at 4°C followed by 12 hours in the light at 22°C. These timepoints were selected to capture the transcriptomes at an early and late time in Phase II of imbibition. Using this experimental design we were able to determine transcriptome differences associated with seed dormancy in the <i>sly1-2</i> mutation (L<i>er</i> wt vs <i>sly1-2</i>(D)), and changes associated with <i>sly1-2</i> dormancy loss through dry after-ripening (<i>sly1-2</i>(AR) vs <i>sly1-2</i>(D)) or through <i>GID1b</i>-overexpression (<i>sly1-2 GID1b-OE</i> vs <i>sly1-2</i>(D)). Seeds for L<i>er</i> wt, <i>sly1-2</i>(D), and <i>sly1-2 GID1b-OE</i> were grown alongside each other under the same conditions and after-ripened for 2 weeks. Seeds from <i>sly1-2</i>(AR) were grown under the same conditions in advance of the other lines to allow for the long after-ripening requirement. RNA was extracted using a phenol-chloroform-based extraction from three biological replicates per treatment.
Transcriptional mechanisms associated with seed dormancy and dormancy loss in the gibberellin-insensitive sly1-2 mutant of Arabidopsis thaliana.
Specimen part, Time
View SamplesRNA sequencing technology has been carried out in order to evaluate mRNA expression changes after manipulation of miR-26a in both MCF-7 and MDA-MB-231 breast cancer cell lines. Overall design: To evaluate the entire set of genes modulated by miR-26a in breast cancer, we performed RNA-seq after ectopic manipulation of this miRNA. We over-expressed miR-26a in MCF-7 epithelial cancer cell lines and also reduced its activity by stably transfecting MDA-MB-231 mesenchymal-like cancer cell lines with a specific sponge vector. GO terms and pathway enriched analysis of the transcripts that significantly change upon miR-26 ectopic manipulation implicates miR-26ab in cell cycle, apoptosis, cell spreading and cell adhesion in breast cancer
Sustained expression of miR-26a promotes chromosomal instability and tumorigenesis through regulation of CHFR.
Specimen part, Cell line, Subject
View SamplesIschemic tolerance can be induced by numerous preconditioning stimuli, including various Toll-like receptor (TLR) ligands. We have shown previously that systemic administration of the TLR4 ligand, lipopolysaccharide (LPS) or the TLR9 ligand, unmethylated CpG ODNs prior to transient brain ischemia in mice confers substantial protection against ischemic damage. To elucidate the molecular mechanisms of preconditioning, we compared brain and blood genomic profiles in response to preconditioning with these TLR ligands and to preconditioning via exposure to brief ischemia.
Multiple preconditioning paradigms converge on interferon regulatory factor-dependent signaling to promote tolerance to ischemic brain injury.
Specimen part, Treatment
View SamplesWe used microarrays to detail the global program of gene expression during early hESC differentiation to mesendoderm using FBS, with and without RUNX1 depletion.
Transient RUNX1 Expression during Early Mesendodermal Differentiation of hESCs Promotes Epithelial to Mesenchymal Transition through TGFB2 Signaling.
Specimen part, Cell line
View SamplesThe signaling molecule retinoic acid (RA) regulates rod and cone photoreceptor fate, differentiation, and survival. The purpose of this study was to identify eye-specific genes controlled by RA during photoreceptor differentiation in the zebrafish.
Retinoic Acid Signaling Regulates Differential Expression of the Tandemly-Duplicated Long Wavelength-Sensitive Cone Opsin Genes in Zebrafish.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Anti-diabetic rosiglitazone remodels the adipocyte transcriptome by redistributing transcription to PPARγ-driven enhancers.
Cell line, Treatment, Time
View SamplesRosiglitazone (rosi) is a powerful insulin sensitizer, but serious toxicities have curtailed its widespread clinical use. Rosi functions as a high-affinity ligand for PPARg, the adipocyte-predominant nuclear receptor (NR). The classic model, involving binding of ligand to the NR on DNA, explains positive regulation of gene expression, but ligand-dependent repression is not well understood. We have now addressed this issue by studying the direct effects of rosiglitazone on gene transcription, using global run-on sequencing (GRO-seq). Rosi-induced changes in gene body transcription were pronounced after 10 minutes and correlated with steady-state mRNA levels as well as with transcription at nearby enhancers (eRNAs). Upregulated eRNAs occurred almost exclusively at PPARg binding sites, to which rosi treatment recruited the coactivator MED1. By contrast, transcriptional repression by rosi involved a loss of MED1 from eRNA sites devoid of PPARg and enriched for other TFs including AP-1 factors and C/EBPs. Thus, rosi activates and represses transcription by fundamentally different mechanisms that could inform the future development of antidiabetic drugs.
Anti-diabetic rosiglitazone remodels the adipocyte transcriptome by redistributing transcription to PPARγ-driven enhancers.
Cell line, Treatment, Time
View SamplesThe onset and progression of breast cancer are linked to genetic and epigenetic changes that alter the normal programming of cells. Epigenetic modifications of DNA and histones contribute to chromatin structure that results in the activation or repression of gene expression. Several epigenetic pathways have been shown to be highly deregulated in cancer cells. Targeting specific histone modifications represents a viable strategy to prevent oncogenic transformation, tumor growth or metastasis. Methylation of histone H3 lysine 4 has been extensively studied and shown to mark genes for expression; however this residue can also be acetylated and the specific function of this alteration is less well known. To define the relative roles of histone H3 methylation (H3K4me3) and acetylation (H3K4ac) in breast cancer, we determined genomic regions enriched for both marks in normal-like (MCF10A), transformed (MCF7) and metastatic (MDA-MB-231) cells using a genome-wide ChIP-Seq approach. Our data revealed a genome-wide gain of H3K4ac associated with both early and late breast cancer cell phenotypes, while gain of H3K4me3 was predominantly associated with late stage cancer cells. Enrichment of H3K4ac was overrepresented at promoters of genes associated with cancer-related phenotypic traits, such as estrogen response and epithelial-to-mesenchymal transition pathways. Our findings highlight an important role for H3K4ac in predicting epigenetic changes associated with early stages of transformation. In addition, our data provide a valuable resource for understanding epigenetic signatures that correlate with known breast cancer-associated oncogenic pathways. Overall design: RNA-Seq of cell lines MCF10A, MCF7 and MDA-MB-231.
Histone H3 lysine 4 acetylation and methylation dynamics define breast cancer subtypes.
No sample metadata fields
View SamplesMyalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) is a syndrome of unknown etiology characterized by profound fatigue exacerbated by physical activity, also known as post-exertional malaise (PEM). Previously, we did not detect evidence of immune dysregulation or virus reactivation outside of PEM periods. Here we sought to determine whether cardiopulmonary exercise stress testing of ME/CFS patients could trigger such changes. ME/CFS patients (n=14) and matched sedentary controls (n=11) were subjected to cardiopulmonary exercise on 2 consecutive days and followed up to 7 days post-exercise, and longitudinal whole blood samples analyzed by RNA-seq. Although ME/CFS patients showed significant worsening of symptoms following exercise versus controls, with 8 of 14 ME/CFS patients showing oxygen consumption (V?O2) on day 2, transcriptome analysis yielded only 6 differentially expressed gene (DEG) candidates when comparing ME/CFS patients to controls across all time points. None of the DEGs were related to immune signaling, and no DEGs were found in ME/CFS patients before and after exercise. Virome composition (P=0.746 by chi-square test) and number of viral reads (P = 0.098 by paired t-test) were not significantly associated with PEM. These observations do not support transcriptionally-mediated immune cell dysregulation or viral reactivation in ME/CFS patients during symptomatic PEM episodes. Overall design: RNAseq of whole blood samples from ME/CFS patients and controls following exercise.
Whole blood human transcriptome and virome analysis of ME/CFS patients experiencing post-exertional malaise following cardiopulmonary exercise testing.
Specimen part, Disease, Disease stage, Treatment, Subject
View SamplesEstrogen receptor-a (ERa) is an important driver of breast cancer and is the target for hormonal therapies, anti-estrogens and drugs that limit estrogen biosynthesis (aromatase inhibitors). Mutations in the ESR1 gene identified in metastatic breast cancer provide a potential mechanism for acquired resistance to hormone therapies. We have used CRISPR-Cas9 mediated genome editing in the MCF-7 breast cancer cell line, generating MCF-7-Y537S. MCF-7-Y537S cells encode a wild-type (tyrosine 537) and a mutant (serine 537) allele. Growth of the line is estrogen-independent and expression of ERa target genes is elevated in the absence of estrogen. ER ChIP-seq was carried out to map global ERa binding sites in the presence and absence of estrogen. RNA-seq following estrogen treatment was used for gene expression analysis. We show that expression of ER target genes and ER recruitment to ER binding regions is similar in MCF-7 and MCF-7-Y537S cells, except that ER recruitment to DNA and expression of ER target genes is frequently elevated in the absence of estrogen. Overall design: Hormone depleted MCF7 Luc or Y537S cells were treated with 10nM E2 or ethanol, as vehicle control, for 8 hours, with 3 replicates (2 replicates for Y537S + E2). RNA-seq was carried out using Illumina Hiseq 2500.
Genomic modelling of the ESR1 Y537S mutation for evaluating function and new therapeutic approaches for metastatic breast cancer.
No sample metadata fields
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