PcG protein complex PRC2 is a methyltransferase specific for histone H3 lysine27, and H3K27me3 is essential for stable transcription silencing. Less well known but quantitatively much more important is the genome-wide role of PRC2 that dimethylates ~70% of total H3K27. Here we show that H3K27me2 occurs in inverse proportion to transcriptional activity in genes and intergenic regions and its loss results in global transcriptional derepression proportionally greatest in previously silent or weakly transcribed regions. H3K27me2 levels are controlled by opposing roaming activities of PRC2 and the H3K27 demethylase dUTX. Unexpectedly, we find an equally pervasive distribution of histone H2A ubiquitylated at lysine 118 (H2AK118ub), attributed to the RING1 subunit of PRC1-type complexes. Overall design: Examination of global changes in transcription genome-wide when E(z) is inactivated by monitoring total RNA from E(z) temperature-sensitive cells at 25°C and 31°C in duplicate
Genome-wide activities of Polycomb complexes control pervasive transcription.
Cell line, Subject
View SamplesTransgenic mice were generated that expressed the inhibitor of apoptosis and mitotic regulator survivin in pancreatic islet beta cells. Control non-transgenic or transgenic islets were then used in a model of islet transplantation in diabetic recipient mice and tested for their ability to correct hyperglycemia and allow long-term engraftment of tranplanted islets in vivo. Control or transgenic islets were analyzed by chip microarray for potential transcriptional changes associated with transgenic expression of survivin, in vivo.
Genome-wide analysis of Polycomb targets in Drosophila melanogaster.
Sex, Age, Specimen part
View SamplesDnmt3a catalyzes DNA methylation of gDNA, which contributes to the transriptional regulations of genes and genomic stability.
Methylation-independent repression of Dnmt3b contributes to oncogenic activity of Dnmt3a in mouse MYC-induced T-cell lymphomagenesis.
Age, Specimen part
View SamplesEffects of Nipped-B and Rad21 sister chromatid cohesin proteins on gene expression data in ML-DmBG3 cells derived from Drosophila melanogaster larval central nervous system
Regulation of the Drosophila Enhancer of split and invected-engrailed gene complexes by sister chromatid cohesion proteins.
Time
View SamplesmRNA expression levels were determined by NGS for wildtype larvae as well as for larvae lacking HP1a [Su(var)205^04/Su(var)205^05 transheterozygotes]. Overall design: RNA samples from wildtype (OR) and HP1a mutant third instar larvae were examined, using duplicate biological samples and Illumina NGS.
Enrichment of HP1a on Drosophila chromosome 4 genes creates an alternate chromatin structure critical for regulation in this heterochromatic domain.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Sequence-specific targeting of dosage compensation in Drosophila favors an active chromatin context.
Cell line
View SamplesThe Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at a subset of sites. However, the consensus sequence motif of entry sites (MSL recognition element or MRE) is only slightly enriched on the X (~2 fold), and only a fraction of them is utilized by the MSL complex. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the NHGRI modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells, which contain MSL complex, and female Kc cells, which lack the complex, we find that the presence of active chromatin modifications, together with an elevated local GC content in surrounding sequence, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites, and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our finding serves as a model to understand how chromatin and local sequence features are involved in the selection of functional protein binding sites in the genome.
Sequence-specific targeting of dosage compensation in Drosophila favors an active chromatin context.
Cell line
View SamplesGut microbes elicit specific changes in gene expression in the colon of mice. We colonized germ-free mice with microbial communities from the guts of humans, zebrafish and termites, human skin and tongue, soil and estuarine microbial mats.
Bacteria from diverse habitats colonize and compete in the mouse gut.
Sex, Specimen part
View SamplesUnderstanding the structure and interplay of cellular signalling pathways is one of the great challenges in molecular biology. Boolean Networks can infer signalling networks from observations of protein activation. In situations where it is difficult to assess protein activation directly, Nested Effect Models are an alternative. They derive the network structure indirectly from downstream effects of pathway perturbations. To date, Nested Effect Models cannot resolve signalling details like the formation of signalling complexes or the activation of proteins by multiple alternative input signals. Here we introduce Boolean Nested Effect Models (B-NEM). B-NEMs combine the use of downstream effects with the higher resolution of signalling pathway structures in Boolean Networks. We show that B-NEMs accurately reconstruct signal flows in simulated data. Using B-NEM we then resolve BCR signalling via PI3K and TAK1 kinases in BL2 lymphoma cell lines.
Analyzing synergistic and non-synergistic interactions in signalling pathways using Boolean Nested Effect Models.
Specimen part, Cell line, Treatment
View SamplesTip60 is a key histone acetyltransferase (HAT) enzyme that plays a central role in diverse biological processes critical for general cell function, however the chromatin-mediated cell-type specific developmental pathways that are dependent exclusively upon the HAT activity of Tip60 remain to be explored. Here, we investigate the role of Tip60 HAT activity in transcriptional control during multicellular development, in vivo by examining genome-wide changes in gene expression in a Drosophila model system specifically depleted for endogenous dTip60 HAT function. We show that amino acid residue E431 in the catalytic HAT domain of dTip60 is critical for the acetylation of endogenous histone H4 in our fly model in vivo, and demonstrate that dTip60 HAT activity is essential for multicellular development. Moreover, our results uncover a novel role for Tip60 HAT activity in controlling neuronal specific gene expression profiles essential for nervous system function as well as a central regulatory role for Tip60 HAT function in general metabolism.
Microarray analysis uncovers a role for Tip60 in nervous system function and general metabolism.
Specimen part
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