This SuperSeries is composed of the SubSeries listed below.
Genome-wide characterization of menin-dependent H3K4me3 reveals a specific role for menin in the regulation of genes implicated in MEN1-like tumors.
Specimen part
View SamplesInactivating mutations in the MEN1 gene predisposing to the multiple endocrine neoplasia type 1 (MEN1) syndrome can also cause sporadic pancreatic endocrine tumors. MEN1 encodes menin, a subunit of MLL1/MLL2-containing histone methyltransferase complexes that trimethylate histone H3 at lysine 4 (H3K4me3). The importance of menin-dependent H3K4me3 in normal and transformed pancreatic endocrine cells is unclear. To study the role of menin-dependent H3K4me3, we performed in vitro differentiation of wild-type as well as menin-null mouse embryonic stem cells (mESCs) into pancreatic islet-like endocrine cells (PILECs). Gene expression analysis and genome-wide H3K4me3 ChIP-Seq profiling in wild-type and menin-null mESCs and PILECs revealed menin-dependent H3K4me3 at the imprinted Dlk1-Meg3 locus in mESCs, and all four Hox loci in differentiated PILECs. Specific and significant loss of H3K4me3 and gene expression was observed for genes within the imprinted Dlk1-Meg3 locus in menin-null mESCs and the Hox loci in menin-null PILECs. Given that the reduced expression of genes within the DLK1-MEG3 locus and the HOX loci is associated with MEN1-like sporadic tumors, our data suggests a possible role for menin-dependent H3K4me3 at these genes in the initiation and progression of sporadic pancreatic endocrine tumors. Furthermore, our investigation also demonstrates that menin-null mESCs can be differentiated in vitro into islet-like endocrine cells, underscoring the utility of menin-null mESC-derived specialized cell types for genome-wide high-throughput studies.
Genome-wide characterization of menin-dependent H3K4me3 reveals a specific role for menin in the regulation of genes implicated in MEN1-like tumors.
Specimen part
View SamplesAcrylamide is a type-2 alkene monomer with established human neurotoxic effects. While the primary source of human exposure to acrylamide is occupational, other exposure sources include food, drinking water, and smoking. In this study, neurobehavioral assays coupled with transcriptional profiling analysis were conducted to assess both behavioral and gene expression effects induced by acrylamide neurotoxicity in rats when administered during early postnatal life. Acrylamide administration in rat pups induced significant characteristic neurotoxic symptoms including increased heel splay, decrease in grip strength, and decrease in locomotor activity. Transcriptome analysis with the Affymetrix Rat Genome 230 2.0 array indicated that acrylamide treatment caused a significant alteration in the expression of genes involved in muscle contraction, pain regulation, and dopaminergic neuronal pathways. First, in agreement with the observed behavioral effects, expression of the Mylpf gene involved in muscle contraction was downregulated in the spinal cord in response to acrylamide. Second, in sciatic nerves, acrylamide repressed the expression of the opioid receptor gene Oprk1 that is known to play a role in neuropathic pain regulation. Finally, in the cerebellum, acrylamide treatment caused a decrease in the expression of the nuclear receptor gene Nr4a2 that is required for development of dopaminergic neurons. Thus, our work examining the effect of acrylamide at the whole-genome level on a developmental mammalian model has identified novel genes previously not implicated in acrylamide neurotoxicity that can be further developed into biomarkers for assessing the risk of acrylamide exposure.
Neurobehavioral and transcriptional effects of acrylamide in juvenile rats.
Sex, Specimen part, Treatment
View SamplesThe recent reports of two circular RNAs (circRNAs) with strong potential to act as microRNA (miRNA) sponges suggest that circRNAs might play important roles in regulating gene expression. However, the global properties of circRNAs are not well understood. We developed a computational pipeline to identify circRNAs and quantify their relative abundance from RNA-seq data. Applying this pipeline to a large set of non-poly(A)-selected RNA-seq data from the ENCODE project, we annotated 7,112 human circRNAs that were estimated to comprise at least 10% of the transcripts accumulating from their loci. Most circRNAs are expressed in only a few cell types and at low abundance, but they are no more cell-type–specific than are mRNAs with similar overall expression levels. Although most circRNAs overlap protein-coding sequences, ribosome profiling provides no evidence for their translation. We also annotated 635 mouse circRNAs, and although 20% of them are orthologous to human circRNAs, the sequence conservation of these circRNA orthologs is no higher than that of their flanking linear exons. The previously proposed miR-7 sponge, CDR1as, is one of only two circRNAs with more miRNA sites than expected by chance, with the next best miRNA-sponge candidate deriving from a primate-specific zinc-finger gene, ZNF91. These results provide a new framework for future investigation of this intriguing topological isoform while raising doubts regarding a biological function of most circRNAs. Overall design: Examination of 9 samples in 1 cell type Note: The ENCODE data we used are under GEO SuperSeries GSE26284 (all samples labeled "_cell_total"). But they were not used in the processing of the U2OS data.
Expanded identification and characterization of mammalian circular RNAs.
No sample metadata fields
View SamplesMEN1 is a tumor suppressor gene loss of which causes lipoma (fatty tumors under the skin) and many other endocrine and non-endocrine tumors. It's target genes in fat cells (adipocytes) are unknown. Gene expression in adipocytes that were in vitro differentiated from mouse embryonic stem cells (mESCs) of Men1-nul l(Men1-KO) and WT mice were compared to assess the expression of genes upon menin loss in adipocytes that could lead to the deveopment of lipoma.
Consequence of Menin Deficiency in Mouse Adipocytes Derived by In Vitro Differentiation.
Specimen part
View SamplesMeg3 is a long non-coding RNA. It's target genes are unknown. The mouse pancreatic beta cell line MIN6-4N was used to assess the expression of genes upon stable Meg3 overexpression
Epigenetic regulation of the lncRNA MEG3 and its target c-MET in pancreatic neuroendocrine tumors.
Specimen part, Cell line
View SamplesAlterations in the composition of the gut microbiome have an emerging role in brain function and behaviour. We have porposed that short chain fatty acids (SCFA) including propionate and butyrate which are present in the diet and are fermantation products of many gastrointestinal bacteria are contributing environmental factors in autism spectrum disorders (ASD). Here we used the microarray technology to compare global changes in gene expression profiles following exposure of PC12 cells to structurally related SCFA propionate and butyrate each in two different concentrations. Large number of affected genes, common for both SCFA were identified, including genetic networks and GO processes implicated in ASD.
Enteric bacterial metabolites propionic and butyric acid modulate gene expression, including CREB-dependent catecholaminergic neurotransmission, in PC12 cells--possible relevance to autism spectrum disorders.
Specimen part
View SamplesRecent studies have reported that competitive endogenous RNAs (ceRNAs) can act as sponges for a miRNA through their binding sites and that changes in ceRNA abundances from individual genes can modulate the miRNA’s activity. Consideration of this hypothesis would benefit from knowing the quantitative relationship between a miRNA and its endogenous target sites. Here, we altered intracellular target-site abundance through expression of a miR-122 target in hepatocytes and livers, and analyzed the effects on miR-122 target genes. Target repression was released in a threshold-like manner at high target-site abundance (=1.5x10^5 added target sites per cell), and this threshold was insensitive to the effective levels of the miRNA. Furthermore, in response to extreme metabolic liver disease models, global target-site abundance of hepatocytes did not change sufficiently to affect miRNA-mediated repression. Thus, modulation of miRNA target abundance is unlikely to cause significant effects on gene expression and metabolism through a ceRNA effect. Overall design: Seventeen mRNA profiles were generated of 1) primary hepatocytes of mice expressing variable levels of a recombinant Adenovirus expressing the transcript of AldolaseA (Ad-AldoA), containing either 1 or 3 sites matching miR-122 or a mutated miR-122 site (no site), 2) primary hepatocytes derived from mice treated with Antagomir-122 (treatment group) or Antagomir-122mm (control group), 3) livers originating of a genetic model (Ldlr deficient mice) causing severe pathological changes in cholesterol metabolism, 4) livers of mice perfused with Insulin or PBS, and 5) livers of mice fed a high-fat or chow diet; most samples were sequenced in duplicate or triplicate by an Illumina HiSeq 2000. One small RNA profile was also generated from livers of mice fed a chow diet by Solexa sequencing.
Assessing the ceRNA hypothesis with quantitative measurements of miRNA and target abundance.
No sample metadata fields
View SamplesThe second heart field (SHF) comprises a population of mesodermal progenitor cells that are added to the nascent linear heart to give rise to the majority of the right ventricle, interventricular septum, and outflow tract of mammals and birds. The zinc finger transcription factor GATA4 functions as an integral member of the cardiac transcription factor network in the SHF and its derivatives. In addition to its role in cardiac differentiation, GATA4 is also required for cardiomyocyte replication, although the transcriptional targets of GATA4 required for proliferation have not been previously identified. In the present study, we disrupted Gata4 function exclusively in the SHF and its derivatives. Gata4 SHF knockout mice die by embryonic day 13.5 and exhibit hypoplasia of the right ventricular myocardium and interventricular septum and display profound ventricular septal defects. Loss of Gata4 function in the SHF results in decreased myocyte proliferation in the right ventricle, and we identify numerous cell cycle genes that are dependent on Gata4 by microarray analysis. We show that Gata4 is required for Cyclin D2 expression in the right ventricle and that the Cyclin D2 promoter is bound and activated by GATA4 via three consensus GATA binding sites. These findings establish Cyclin D2 as a direct transcriptional target of GATA4 and support a model in which GATA4 controls cardiomyocyte proliferation by coordinately regulating numerous cell cycle genes.
GATA4 is a direct transcriptional activator of cyclin D2 and Cdk4 and is required for cardiomyocyte proliferation in anterior heart field-derived myocardium.
No sample metadata fields
View SamplesA series of transfections was performed in Drosophila S2 cells to explore: 1) the types of target sites that Drosophila microRNAs recognize, 2) the relative functional efficacy of these sites in mediating repression, and 3) the determinants that allow some sites to have greater potency than others. 3p-seq was also performed to help reannotate and quantify the landscape of 3'' UTRs in Drosophila S2 cells. Overall design: Nine mRNA profiles were generated, with Drosophila S2 cells transfected with one of 6 microRNAs (miR-1, miR-4, miR-92a, miR-124, miR-263a, and miR-997). These samples were compared to 3 biological replicates of a mock transfection condition. 3p-seq data for S2 cells was also generated to help reannotate and quantify 3'' UTR isoforms.
Predicting microRNA targeting efficacy in Drosophila.
Specimen part, Subject
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