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GSE34390
Drosophila melanogaster
29 Downloadable Samples
Affymetrix Drosophila Genome 2.0 Array (drosophila2)
Description
Transcription regulation involves enzyme-mediated changes in chromatin structure. Here, we describe a novel mode of histone crosstalk during gene silencing, in which histone H2A monoubiquitylation is coupled to the removal of histone H3 Lys 36 dimethylation (H3K36me2). This pathway was uncovered through the identification of dRING-associated factors (dRAF), a novel Polycomb group (PcG) silencing complex harboring the histone H2A ubiquitin ligase dRING, PSC and the F-box protein, and demethylase dKDM2. In vivo, dKDM2 shares many transcriptional targets with Polycomb and counteracts the histone methyltransferases TRX and ASH1. Importantly, cellular depletion and in vitro reconstitution assays revealed that dKDM2 not only mediates H3K36me2 demethylation but is also required for efficient H2A ubiquitylation by dRING/PSC. Thus, dRAF removes an active mark from histone H3 and adds a repressive one to H2A. These findings reveal coordinate trans-histone regulation by a PcG complex to mediate gene repression.
Publication Title
dKDM2 couples histone H2A ubiquitylation to histone H3 demethylation during Polycomb group silencing.
Sample Metadata Fields
Cell line
View Samples- Mus musculus
- 6 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
The spatial organization of DNA in the cell nucleus is an emerging key contributor to genomic function. We have developed 4C technology, or 3C-on-chip, which allows for an unbiased genome-wide search for DNA loci that contact a given locus in the nuclear space. We demonstrate here that active and inactive genes are engaged in many long-range intrachromosomal interactions and can also form interchromosomal contacts. The active b-globin locus in fetal liver contacts mostly transcribed, but not necessarily tissue-specific, loci elsewhere on chromosome 7, while the inactive locus in fetal brain contacts different, transcriptionally silent, loci. A housekeeping gene in a gene dense region on chromosome 8 forms long-range contacts predominantly with other active gene clusters, both in cis and in trans, and many of these intra- and interchromosomal interactions are conserved between the tissues analyzed. Our data demonstrate that chromosomes fold into areas of active chromatin and areas of inactive chromatin and establish 4C technology as a powerful tool to study nuclear architecture.
Publication Title
Nuclear organization of active and inactive chromatin domains uncovered by chromosome conformation capture-on-chip (4C).
Sample Metadata Fields
Specimen part
View Samples- Drosophila melanogaster
- 4 Downloadable Samples
Illumina HiSeq 2000
Description
Nucleosome structure and positioning play pivotal roles in gene regulation, DNA repair and other essential processes in eukaryotic cells. Nucleosomal DNA is thought to be uniformly inaccessible to DNA binding and processing factors, such as MNase. Here, we show, however, that nucleosome accessibility and sensitivity to MNase varies. Digestion of Drosophila chromatin with two distinct concentrations of MNase revealed two types of nucleosomes: sensitive and resistant. MNase-resistant nucleosome arrays are less accessible to low concentrations of MNase, whereas MNase-sensitive arrays are degraded by high concentrations. MNase-resistant nucleosomes assemble on sequences depleted of A/T and enriched in G/C containing dinucleotides. In contrast, MNase-sensitive nucleosomes form on A/T rich sequences represented by transcription start and termination sites, enhancers and DNase hypersensitive sites. Lowering of cell growth temperature to ~10°C stabilizes MNase-sensitive nucleosomes suggesting that variations in sensitivity to MNase are related to either thermal fluctuations in chromatin fiber or the activity of enzymatic machinery. In the vicinity of active genes and DNase hypersensitive sites nucleosomes are organized into synchronous, periodic arrays. These patterns are likely to be caused by “phasing” nucleosomes off a potential barrier formed by DNA-bound factors and we provide an extensive biophysical framework to explain this effect. Overall design: RNA-seq S2 cells Drosophila melanogaster
Publication Title
Genome-wide profiling of nucleosome sensitivity and chromatin accessibility in Drosophila melanogaster.
Sample Metadata Fields
Specimen part, Subject
View Samples- Arabidopsis thaliana
- 6 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
The bundle sheath cells (BSCs) layer a presumed control point for radial transport of water and solutes between the vasculature and the leaf mesophyll cells (MCs) is still largely understudied. Using isolated protoplasts, we found that 45% of the 90 genes differentially expressed in BSCs vs. MCs are membrane related and 20% are transport related, suggesting unique functionality of membrane transport in the BSCs, supported also by functional assays (electrophysiology and fluorescence imaging).
Publication Title
Differential gene expression and transport functionality in the bundle sheath versus mesophyll - a potential role in leaf mineral homeostasis.
Sample Metadata Fields
Specimen part
View Samples- Drosophila melanogaster
- 6 Downloadable Samples
- Illumina HiSeq 2000
Description
RNA sequencing data for replicates of E347 driver control, E347 neuronal ablation per Shi dominant-negative expression and activation per NachBac expression to identify differences in RNA abundancy Overall design: E347 driver control, E347 neuronal ablation per Shi dominant-negative expression and activation per NachBac expression
Publication Title
Coordination between Drosophila Arc1 and a specific population of brain neurons regulates organismal fat.
Sample Metadata Fields
Specimen part, Subject
View Samples- Homo sapiens
- 37 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
The RPMI-8226 human multiple myeloma cell line was stably infected with either a validated shRNA against BMI1 or a control shRNA. RNA was prepared from these lines, +/- doxycycline induction and at various time points post-induction. Samples were hybridized on the Affymetrix U133plus2 human genome expression microarray.
Publication Title
The Polycomb group protein Bmi-1 is essential for the growth of multiple myeloma cells.
Sample Metadata Fields
Cell line
View Samples- Homo sapiens
- 2 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Adenosine to Inosine (A-to-I) RNA editing is a site-specific modification of RNA transcripts, catalyzed by members of the ADAR (Adenosine Deaminase Acting on RNA) protein family. RNA editing occurs in human RNA in thousands of different sites. Some of the sites are located in protein-coding regions but the majority is found in non-coding regions, such as 3UTRs, 5UTRs and introns - mainly in Alu elements. While editing is found in all tissues, the highest levels of editing are found in the brain. It was shown that editing levels within protein-coding regions are increased during embryogenesis and after birth and that RNA editing is crucial for organism viability as well as for normal development. In this study we characterized the A-to-I RNA editing phenomenon during neuronal and spontaneous differentiation of human embryonic stem cells (hESCs). We identified high editing levels of Alu repetitive elements in hESCs and demonstrated a global decrease in editing levels of non-coding Alu sites when hESCs are differentiating, particularly into the neural lineage. Using RNA interference, we showed that the elevated editing levels of Alu elements in undifferentiated hESCs are highly dependent on ADAR1. DNA microarray analysis showed that ADAR1 knockdown has a global effect on gene expression in hESCs and leads to a significant increase in RNA expression levels of genes involved in differentiation and development processes, including neurogenesis. Taken together, our data suggest that A-to-I editing of Alu sequences plays a role in the regulation of hESC early differentiation decisions.
Publication Title
Alu sequences in undifferentiated human embryonic stem cells display high levels of A-to-I RNA editing.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 15 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Bmi-1 and Mel-18 are close structural homologues that belong to the polycomb group (PcG) of transcriptional regulators of homeotic gene expression in development. They are believed to stably maintain repression of gene expression by altering the state of chromatin at specific promoters. A number of clinical and experimental observations have also implicated Bmi-1 in tumorigenesis and stem cell maintenance. Bmi-1 overexpression or amplification has been observed in a number of human malignancies, particularly in B-cell lymphomas, medulloblastomas and breast cancer. We report here that shRNA-mediated knock-down of either Bmi-1 or Mel-18 in human medulloblastoma DAOY cells results in the inhibition of proliferation, loss of clonogenic survival and anchorage-independent growth, and suppression of xenograft tumor formation in nude mice. Furthermore, overexpression of both Bmi-1 and Mel-18 significantly increased clonogenic survival of Rat1 fibroblasts. In contrast, stable downregulation of Bmi-1 or Mel-18 alone did not affect the growth of SK-OV-3 or U2OS cancer cell lines or normal human WI38 fibroblasts. Gene expression analysis of shRNA-expressing DAOY cells has demonstrated a significant overlap in the Bmi-1- and Mel-18-regulated genes and revealed novel gene targets under their control. Taken together, these results suggest that Bmi-1 and Mel-18 might have overlapping functions in human tumorigenesis.
Publication Title
Contribution of polycomb homologues Bmi-1 and Mel-18 to medulloblastoma pathogenesis.
Sample Metadata Fields
No sample metadata fields
View Samples- Macaca mulatta
- 25 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Lassa fever (LF) is a rodent-borne viral disease that can be fatal for human beings. In this study, an attenuated Lassa vaccine candidate, ML29, was tested in SIV-infected rhesus macaques for its ability to elicit immune responses without instigating signs of virulent disease. ML29 is a reassortant between Lassa and Mopeia viruses that causes a transient infection in non-human primates and confers sterilizing protection from lethal Lassa viral challenge. However, since the LF endemic area of West Africa also has high HIV seroprevalence, it is important to determine whether vaccination could be safe in the context of AIDS. SIV-infected and uninfected rhesus macaques were vaccinated with the ML29 virus and monitored for classical and non-classical signs of arenavirus disease. Classical disease signs included viremia, rash, weight loss, high liver enzyme levels, and virus invasion of the central nervous system. Non-classical signs derived from profiling the blood transcriptome of virulent and non-virulent arenavirus infections included increased expression of interferon response genes and decreased expression of COX2, IL-1?, coagulation intermediates and nuclear receptors needed for stress signaling. Here it is demonstrated that SIV-infected and uninfected rhesus macaques responded similarly to ML29 vaccination, and that none developed signs of arenavirus disease or persistence. Furthermore, 5 of 5 animals given a heterologous challenge with a lethal dose of LCMV-WE survived without developing disease signs.
Publication Title
An attenuated Lassa vaccine in SIV-infected rhesus macaques does not persist or cause arenavirus disease but does elicit Lassa virus-specific immunity.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 10 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Liquid biopsy profile which can screen for early CRC. We aimed to depict the profile of early stage CRC as well as for advanced adenomas by combination of current molecular knowledge with microarray technology, using efficient circulating free RNA purification from blood and RNA amplification technologies.
Publication Title
Feasibility of Unbiased RNA Profiling of Colorectal Tumors: A Proof of Principle.
Sample Metadata Fields
Sex
View Samples