The microbial population that live within the gut of animals influences their physiology. We used axenic and recolonized flies to identify genes whose expression is modulated by the presence of a bacterial flora in the gut.
Drosophila microbiota modulates host metabolic gene expression via IMD/NF-κB signaling.
Specimen part, Treatment
View SamplesRecent studies have revealed a myriad of non-coding transcripts in different organisms. For instances, the presence of short bidirectional transcripts is a hallmark of active promoters in mammals, while upstream non-coding transcripts can be detected at most expressed genes in conditions where the RNA degradation machinery is inhibited. Here, we used RNA-seq with very high sequencing depth to characterize strand specific transcripts from primary mouse tissues. We found that a substantial fraction of gene promoters sustain expression of long non-coding antisense transcripts. These transcripts have an average size of 6 kb, have features of mature transcripts, but remain associated with the chromatin. We named this new class of non-coding RNAs Long Upstream Antisense Transcripts (LUAT). Strikingly, the LUAT and coding gene pairs are usually co-regulated, with the associated genes often/generally coding for transcriptional regulators functioning during development and cell differentiation. Indeed, these bidirectional promoters share several characteristic of developmental gene promoters, including large CpG islands and high degree of conservation, and display symetrical GC skews. Finally, we found that bidirectional promoters have enlarged platforms of Pol II initiation, associated with an intensified rate of early transcriptional elongation. We concluded that promoters of developmental regulators are characterized by a specialized mechanism of Pol II transcription, whereby Pol II poising is directly coupled to relaxed bidirectional transcription. Overall design: Expression of noncoding RNA transcripts in CD4-,CD8- double negative thymocytes from Rag2-/- mice was studied by strand-specific, ribosomal-depleted RNA-seq experiment, using Illumina sequencer
Divergent transcription is associated with promoters of transcriptional regulators.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Bacterial control of host gene expression through RNA polymerase II.
Sex, Cell line
View SamplesUrinary tract infections (UTIs) constitute a highly relevant model of microbial adaptation, in which the contrasting effects of pathogens and commensals on host tissues are clearly displayed. While virulent Escherichia coli cause severe, potentially life-threatening disease by breaking the inertia of the mucosal barrier and infecting the kidneys, the most common outcome of bacteriuria is an asymptomatic carrier state resembling commensalism at other mucosal sites. It remains unclear if the lack of destructive inflammation merely reflects low virulence or if carrier strains actively inhibit disease associated responses in the host. To address this question, we examined the effects of asymptomatic bacterial carriage on host gene expression.
Bacterial control of host gene expression through RNA polymerase II.
Sex
View SamplesUrinary tract infections (UTIs) constitute a highly relevant model of microbial adaptation, in which the contrasting effects of pathogens and commensals on host tissues are clearly displayed. While virulent Escherichia coli cause severe, potentially life-threatening disease by breaking the inertia of the mucosal barrier and infecting the kidneys, the most common outcome of bacteriuria is an asymptomatic carrier state resembling commensalism at other mucosal sites. It remains unclear if the lack of destructive inflammation merely reflects low virulence or if carrier strains actively inhibit disease associated responses in the host. To address this question, we examined the effects of asymptomatic bacterial carriage on host gene expression.
Bacterial control of host gene expression through RNA polymerase II.
Cell line
View SamplesThe mechanisms involved in the maintenance of memory IgE responses are poorly understood, and the role played by germinal center (GC) IgE cells in these memory responses is particularly unclear. IgE B-cell differentiation is characterized by a transient GC phase, a bias towards the plasma cell (PC) fate, and dependence on sequential switching for the production of high-affinity IgE. We show here that IgE GC B cells are unfit to undergo the conventional GC differentiation program due to impaired B-cell receptor function and increased apoptosis. IgE GC cells fail to populate the GC light zone and are unable to contribute to the memory and long-lived PC compartments. Furthermore, we demonstrate that direct and sequential switching are linked to distinct B-cell differentiation fates: direct switching generates IgE GC cells, whereas sequential switching gives rise to IgE plasma cells. We propose a comprehensive model for the generation and memory of IgE responses.
The distinctive germinal center phase of IgE+ B lymphocytes limits their contribution to the classical memory response.
Specimen part, Treatment
View SamplesDespite the availability of large-scale transcriptomics data, specific long noncoding RNAs (lncRNAs) expressed in specific brain regions and populations of neurons are poorly understood. Here we report analysis of expression of lncRNAs and mRNAs expressed in hippocampus and prefrontal cortex (PFC), two regions of brain that are involved in memory storage and neuropsychiatric disorders. Our unbiased analyses have identified specific lncRNAs and mRNAs that are enriched in hippocampus and PFC. We have identified several regions in the chromosomes characterized by clustered lncRNA expression suggesting the transcriptional hotspots of lncRNA in the genome. We find that, a subset of lncRNAs and protein coding genes in their vicinity are uniquely co-expressed in specific brain regions and thus presumably co-regulated. Furthermore, specific brain regions and neuronal populations have characteristic lncRNA expression profile. These studies reveal unexpected complexity in the expression profiles of lncRNAs in the mammalian brain. Overall design: Examination of mRNAs and long noncoding RNAs in mouse hippocampus and prefrontal cortex of 8 adult mice.
Transcriptome analyses of adult mouse brain reveal enrichment of lncRNAs in specific brain regions and neuronal populations.
No sample metadata fields
View SamplesThis study was aimed at understanding the genome-wide binding and regulatory role of the DAXX transcriptional repressor, recently implicated in PCa. ChIP-Seq analysis of genome-wide distribution of DAXX in PC3 cells revealed over 59,000 DAXX binding sites, found at regulatory enhancers and promoters. ChIP-Seq analysis of DNA methyltransferase 1 (DNMT1), which is a key epigenetic partner for DAXX repression, revealed that DNMT1 binding was restricted to a small number of DAXX sites. DNMT1 and DAXX bound close to transcriptional activator motifs. DNMT1 sites were found to be dependent on DAXX for recruitment by analyzing DNMT1 ChIP-Seq following DAXX knockdown (K/D), corroborating previous findings that DAXX recruits DNMT1 to repress its target genes. Massively parallel RNA sequencing (RNA-Seq) was used to compare the transcriptomes of WT and DAXX K/D PC3 cells. Genes induced by DAXX K/D included those involved in autophagy, and DAXX ChIP-Seq peaks were found close to the transcription start sites (TSS) of autophagy genes, implying they are more likely to be regulated by DAXX. Overall design: Determine changes in gene expression levels between WT and DAXX K/D prostate cancer cells by RNA-Seq (PC3 Cells).
The DAXX co-repressor is directly recruited to active regulatory elements genome-wide to regulate autophagy programs in a model of human prostate cancer.
No sample metadata fields
View SamplesEstrogen signaling and epigenetic modifications, in particular DNA methylation, are involved in regulation of gene expression in breast cancers. Here we investigated a potential regulatory cross-talk between these two pathways by identifying their common target genes and exploring potential underlying molecular mechanisms in human MCF7 breast cancer cells. Principal Findings: Gene expression profiling revealed that the expression of approximately 150 genes was influenced by both 17-estradiol (E2) and a hypomethylating agent 5-aza-2-deoxycytidine (DAC). Based on gene ontology (GO), CpG island prediction analysis and previously reported estrogen receptor (ER) binding regions, we selected six genes for further analysis (BTG3, FHL2, PMAIP1, BTG2, CDKN1A and TGFB2). GO analysis suggests that these genes are involved in intracellular signaling cascades, regulation of cell proliferation and apoptosis, while CpG island prediction of promoter regions reveals that the promoters of these genes contain at least one CpG island. Using chromatin immunoprecipitation, we show that ER is recruited to CpG islands in promoters, but neither in an E2- nor in a DAC-dependent fashion. DAC treatment reactivates the expression of all selected genes although only the promoters of BTG3 and FHL2 genes are methylated, with E2 treatment showing no effect on the methylation status of these promoters. Conclusions: We identified a set of genes regulated by both estrogen signaling and DNA methylation. However, our data does not support a direct molecular interplay of mediators of estrogen and epigenetic signaling at promoters of regulated genes.
Global identification of genes regulated by estrogen signaling and demethylation in MCF-7 breast cancer cells.
Cell line
View SamplesIn order to confirm the role of fatty acid -oxidation in Src regulation, we performed gene expression analysis in MDA231 cells from in vivo model treated with ETX or knockdown of CPT1 or CPT2 using shRNA. As expected, inhibition of -oxidation showed a gene expression pattern that is opposite to the published Src regulated gene pattern. The known Src up-regulated genes are down-regulated and Src down-regulated genes are up-regulated in -oxidation inhibited cells. Western Blotting further confirmed the gene expression pattern. Knockdown of CPT1 or CPT2 inhibited Src Y416 autophosphorylation as observed with ETX.
Fatty Acid Oxidation-Driven Src Links Mitochondrial Energy Reprogramming and Oncogenic Properties in Triple-Negative Breast Cancer.
Cell line
View Samples