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SRP056871
Mus musculus
16 Downloadable Samples
IlluminaHiSeq2000
Description
Numerous chromatin-remodelling factors are regulated by interactions with RNA. However, the contexts in which chromatin-remodelling factors encounter various RNA species, as well as the molecular functions of RNA binding, are poorly understood. Here we show that R-loops, RNA:DNA hybrids consisting of nascent transcripts hybridized to template DNA strands, facilitate embryonic stem cell (ESC) differentiation by modulating the binding of two key chromatin-remodelling enzymes near gene promoters. As previously shown for polycomb repressive complex 2 (PRC2)1-5, we find that the Tip60-p400 histone acetyltransferase and nucleosome-remodelling complex binds in cis to nascent transcripts. However, whereas chromatin binding by PRC2 is broadly inhibited by transcription6, transcription is necessary for maximal Tip60-p400 binding at most target loci. Given that nascent transcripts expressed from GC-rich promoters frequently form R-loops7, we mapped the genomic locations of R-loops in mouse ESCs, observing higher average Tip60-p400 levels and lower average PRC2 levels at genes with R-loops near their transcription start sites (TSSs). Disruption of R-loops by overexpression of RNaseH1 broadly reduced Tip60-p400 and increased PRC2 enrichment, demonstrating R-loops exert both positive and negative effects on chromatin association by regulatory factors. Consistent with these findings, RNaseH1 overexpression results in widespread changes in gene expression and inhibits ESC differentiation, allowing undifferentiated cells to persist for at least two weeks after differentiation is induced. These results define a novel mechanism by which promoter-proximal R-loops modulate chromatin structure to facilitate changes in cellular identity. Overall design: We examined the transcriptional profile in control and RNaseH1 overexpression mouse ES cells during differentiation.
Publication Title
R loops regulate promoter-proximal chromatin architecture and cellular differentiation.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 12 Downloadable Samples
Description
Approximately 75% of the human genome is transcribed, the majority of which does not encode protein. However, most noncoding RNA (ncRNA) is rapidly degraded after transcription, and relatively few have established functions, questioning the significance of this observation. Here we show that esBAF, a SWI/SNF family nucleosome remodeling factor, suppresses transcription of ncRNAs from approximately 57,000 nucleosome-depleted regions (NDRs) throughout the genome of mouse embryonic stem cells (ESCs). We show that esBAF functions both to keep NDRs nucleosome-free and to promote elevated nucleosome occupancy adjacent to NDRs. Reduction of adjacent nucleosome occupancy upon esBAF depletion is strongly correlated with ncRNA expression, suggesting that flanking nucleosomes form a barrier to pervasive transcription. Upon forcing nucleosome occupancy near an NDR using a nucleosome-positioning sequence, we find that esBAF is no longer required to silence transcription. These data reveal a novel role for esBAF in suppressing pervasive transcription from open chromatin regions in ESCs. Overall design: Examine nucleosome occupancy (MNase-Seq) and transcript production (CapSeq and RNA-Seq) in EGFP KD and Smarca4 KD ESCs
Publication Title
Suppression of pervasive noncoding transcription in embryonic stem cells by esBAF.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 12 Downloadable Samples
- NextSeq 500
Description
The transcriptomes of differentiated and undifferentiated E14 (male), Pgk12.1 (female; WT) and Pgk12.1 with a KO of Rlim (RlimKO) were elucidated and examined for differences in X chromosome inactivation. No significant differences between wt and RlimKO with respect to Xist expression and global X-silencing was detected. Results confirm that Rlim is not required for XCI in female ESCs. Overall design: Transciptomes of female WT (Pgk12.1) and female RlimKO ESCs were compared to those of male ESCs (E14). State of XCI in undifferentiated and differentiated ESCs was determined by comparing expression of Xist and expression of X-linked genes female versus male.
Publication Title
Rlim-Dependent and -Independent Pathways for X Chromosome Inactivation in Female ESCs.
Sample Metadata Fields
Sex, Specimen part, Cell line, Subject
View Samples- Pseudomonas aeruginosa
- 4 Downloadable Samples
Affymetrix Pseudomonas aeruginosa Array (paeg1a)
Description
Many Gram-negative bacteria employ cell-to-cell communication mediated by N-acyl homoserine lactones (quorum sensing) to control expression of a wide range of genes including, but not limited to, genes encoding virulence factors. Outside the laboratory, the bacteria live in complex communities where signals may be perceived across species. We here present a newly found natural quorum sensing inhibitor, produced by the pseudomonads Pseudomonas sp. B13 and Pseudomonas reinekei MT1 as a blind end in the biodegradation of organochloride xenobiotics, which inhibits quorum sensing in P.aeruginosa in naturally occurring concentrations. This catabolite, 4-methylenebut-2-en-4-olide, also known as protoanemonin, has been reported to possess antibacterial properties, but seems to have dual functions. Using transcriptomics and proteomics, we found that protoanemonin significantly reduced expression of genes and secretion of proteins known to be under control of quorum sensing in P.aeruginosa. Moreover, we found activation of genes and gene products involved in iron starvation response. It is thus likely that inhibition of quorum sensing, as the production of antibiotics, is a phenomenon found in complex bacterial communities.
Publication Title
Protoanemonin: a natural quorum sensing inhibitor that selectively activates iron starvation response.
Sample Metadata Fields
Compound
View Samples- Homo sapiens
- 13 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Gene expression from cord blood stem cells and respective derived neuronal cells at different times point of differentiation:CD133+ cells;
Publication Title
Cord blood-derived neuronal cells by ectopic expression of Sox2 and c-Myc.
Sample Metadata Fields
Specimen part, Time
View Samples- Homo sapiens
- 14 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
The mTOR (mammalian Target of Rapamycin) pathway is constitutively activated in Diffuse Large B-Cell Lymphoma (DLBCL). mTOR inhibition has been shown to have clinical activity in patients with DLBCL, although overall response rates remain low. We therefore evaluated differences in the transcriptome between DLBCL cell lines with differential sensitivity to the mTOR inhibitor Rapamycin, to (A) identify gene-expression patterns(GEP) capable of identifying sensitivity to Rapamycin, (B) understand the underlying mechanisms of resistance to Rapamycin in DLBCL and (C) identify bioactive molecules likely to synergize with mTOR inhibitors. Using Affymetrix HuGene ST 1.0 microarrays, we were able to identify a gene expression signature capable of accurately predicting sensitivity and resistance to Rapamycin in DLBCL cell lines. Pathway analysis identified the serine/threonine kinase Akt as central to the differentially-expressed gene network. Connectivity mapping of our datasets identified compounds targeting the AKT pathway with a high likelihood of reversing the GEP associated with resistance to Rapamycin. Specifically, we evaluated the HIV protease inhibitor (PI) Nelfinavir, which is known to have anti-cancer and Akt-inhibitory properties, as well as the small molecule Akt inhibitor MK-2206, for their potential to synergize with to Rapamycin in DLBCL. Nelfinavir and MK-2206 caused profound inhibition of cell viability in combination with Rapamycin in DLBCL cell lines. Low nanomolar concentrations of Rapamycin inhibited phosphorylation of Akt and also downstream targets of activated mTOR when used in combination with these Akt inhibitors. These findings have the potential to significantly improve patient selection for mTOR inhibitor therapy, and to improve rates and depths of response. More broadly, they support the use of global RNA expression and connectivity mapping to improve patient selection and identify synergistic drug combinations for cancer therapy.
Publication Title
Akt inhibitors MK-2206 and nelfinavir overcome mTOR inhibitor resistance in diffuse large B-cell lymphoma.
Sample Metadata Fields
Cell line
View Samples- Homo sapiens
- 25 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Acute Myeloid Leukemia (AML) is a heterogeneous disease from the molecular and biological standpoints, and even patients with a specific gene expression profile may present clinical and molecular heterogeneity. We studied the epigenetic profiles of a cohort of patients that shared a common gene expression profile but differed in that only half of them harbored mutations of the CEBPA locus, while the rest presented with silencing of this gene and co-expression of certain T cell markers. DNA methylation studies revealed that these two groups of patients could be readily segregated in an unsupervised fashion based on their DNA methylation profiles alone. Furthermore, CEBPA silencing was associated with the presence of an aberrant DNA hypermethylation signature, which was not present in the CEBPA mutant group. This aberrant hypermethylation occurred more frequently at sites within CpG islands. CEBPA silenced leukemias also displayed marked hypermethylation when compared with normal CD34+ hematopoietic cells, while CEBPA mutant cases showed only mild changes in DNA methylation when compared to these normal progenitors. Biologically, CEBPA silenced leukemias presented with a decreased response to myeloid growth factors in vitro.
Publication Title
Genome-wide epigenetic analysis delineates a biologically distinct immature acute leukemia with myeloid/T-lymphoid features.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 24 Downloadable Samples
- Affymetrix Human Genome U133A 2.0 Array (hgu133a2)
Description
The association of cytosine methylation and gene expression in the human kidneys is yet to be determined, here we have 25 pairs of the methylation and gene expression profile.
Publication Title
Cytosine methylation changes in enhancer regions of core pro-fibrotic genes characterize kidney fibrosis development.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 52 Downloadable Samples
- Affymetrix Human Genome U133A 2.0 Array (hgu133a2)
Description
Males are 50% more likely to develop end stage kidney failure compared to women. In this study we wanted to find out the molecular mechanism responsible for this increased risk. We collected kidney samples from patients with and without kidney disease and performed a comprehensive gene expression analysis in healthy and diseased male and female kidneys.
Publication Title
Human and murine kidneys show gender- and species-specific gene expression differences in response to injury.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 20 Downloadable Samples
- Affymetrix Mouse Genome 430A 2.0 Array (mouse430a2)
Description
Males are 50% more likely to develop end stage kidney failure compared to women. As a model of the human condition we analyzed gene expression changes in healthy and diseased mouse kidneys.
Publication Title
Human and murine kidneys show gender- and species-specific gene expression differences in response to injury.
Sample Metadata Fields
No sample metadata fields
View Samples