The basic unit of genome packaging is the nucleosome, and nucleosomes have long been proposed to restrict DNA accessibility both to damage and to transcription. However, nucleosome number in cells was considered fixed, and no condition was described where nucleosome number was reduced. We show here that mammalian cells lacking High Mobility Group Box 1 protein (HMGB1) contain a reduced amount of core, linker and variant histones, and a correspondingly reduced number of nucleosomes. Yeast nhp6 mutants lacking NHP6A and B proteins, which are related to HMGB1, also have a reduced amount of histones and fewer nucleosomes. Nucleosome limitation in both mammalian and yeast cells increases the sensitivity of DNA to damage, increases transcription globally, and the relative expression of about 10% of genes. In yeast nhp6 cells the loss of more than one nucleosome in four does not affect the location of nucleosomes and their spacing, but nucleosomal occupancy. The decrease in nucleosomal occupancy is non-uniform, and our results can be modelled assuming that different nucleosomal sites compete for the available histones: sites with high affinity are almost always packaged into nucleosomes both in wt and nucleosome-depleted cells, whereas sites with low affinity are less frequently packaged in nucleosome-depleted cells. We suggest that by modulating the occupancy of nucleosomes histone availability may constitute a novel layer of epigenetic regulation.
Substantial histone reduction modulates genomewide nucleosomal occupancy and global transcriptional output.
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View SamplesTh17 cells were sorted ex vivo from PB of healthy donors as CD4+CD161+CCR6+CXCR3-. Following, cells were transduced with a lentiviral vector carrying the Eomes gene or with an empty vector. Infected cells were then enriched by MACS separation using the reporter gene NGFR as selection marker. Finally, cells were frozen for RNA analysis.
Eomes controls the development of Th17-derived (non-classic) Th1 cells during chronic inflammation.
Cell line
View SamplesExpression profiles at various time points after surgical intervention for pressure-overload induced cardiac hypertrophy and failure.
Small proline-rich protein 1A is a gp130 pathway- and stress-inducible cardioprotective protein.
Sex, Age, Specimen part, Disease, Disease stage, Subject
View SamplesIn this study we applied differential gene expression analysis to exfoliated human urothelia obtained from patients of known bladder disease status. Selected targets from the microarray data were validated in an independent set of samples using a quantitative PCR approach.
A candidate molecular biomarker panel for the detection of bladder cancer.
Specimen part, Disease
View SamplesMutants in the Drosophila gene lethal (3) malignant brain tumor cause malignant growth in the larval brain. This data shows the changes in gene expression profile associated to mutations in l(3)mbt, both in situ in third instar larval brains and in tumors cultured for 1 5 and 10 (T1, T5, T10) rounds of allograft culture
Ectopic expression of germline genes drives malignant brain tumor growth in Drosophila.
No sample metadata fields
View SamplesBJAB cells over expressing KSHV PAN RNA
Regulation of viral and cellular gene expression by Kaposi's sarcoma-associated herpesvirus polyadenylated nuclear RNA.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Epipolymorphisms associated with the clinical outcome of autoimmune arthritis affect CD4+ T cell activation pathways.
Sex
View SamplesMultifactorial diseases, including autoimmune juvenile idiopathic arthritis (JIA), result from a complex interplay between genetics and environment. Epigenetic mechanisms are believed to integrate such gene-environment interactions, fine-tuning gene expression and possibly contributing to immune system dysregulation. Although anti-TNF therapy has strongly increased JIA remission rates, it is not curative and up to 80% of patients flare upon treatment withdrawal. Thus, a crucial unmet medical and scientific need is to understand the immunological mechanisms associated with remission or flare to inform clinical decisions. Here, we explored the CD4+ T cell DNA methylome of 68 poly-articular and extended oligo-articular JIA patients, before and after anti-TNF therapy withdrawal, to identify features associated with maintenance of inactive disease (ID). Individual CpG sites were clustered in coherent modules without a priori knowledge of their function through network analysis. The methylation level of several CpG modules, specifically those enriched in CpG sites belonging to genes that mediate T cell activation, uniquely correlated with clinical activity. Differences in DNA methylation were already detectable at the time of therapy discontinuation, suggesting epigenetic predisposition. RNA profiling also detected differences in T cell activation markers, including HLA-DR, but, overall, its sensitivity was lower than epigenetic profiling. Changes to the T cell activation signature at the protein level were detectable by flow cytometry, confirming the biological relevance of the observed alterations in methylation. Our work proposes, for the first time, epigenetic discrimination between clinical activity states, and reveals T cell-related biological functions tied to, and possibly predicting and/or causing, clinical outcome.
Epipolymorphisms associated with the clinical outcome of autoimmune arthritis affect CD4+ T cell activation pathways.
Sex
View SamplesWe exploited microarrays to detail the global program of gene expression underlying normal stem cells and cancer stem cells in the cerebellum and in medulloblastomas (MBs).
Gene signatures associated with mouse postnatal hindbrain neural stem cells and medulloblastoma cancer stem cells identify novel molecular mediators and predict human medulloblastoma molecular classification.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Importance of Comprehensive Molecular Profiling for Clinical Outcome in Children With Recurrent Cancer.
No sample metadata fields
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