The tumor suppressor p53 is a transcription factor that coordinates the cellular response to DNA damage. Here we provide an integrated analysis of p53 genomic occupancy and p53-dependent gene regulation in the splenic B and non-B cell compartments of mice exposed to whole-body ionizing radiation, providing insight into general principles of p53 activity in vivo. In unstressed conditions, p53 bound few genomic targets; induction of p53 by ionizing radiation increased the number of p53 bound sites, leading to highly overlapping profiles in the different cell types. Comparison of these profiles with chromatin features in unstressed B cells revealed that, upon activation, p53 localized at active promoters, distal enhancers, and a smaller set of unmarked distal regions. At promoters, recognition of the canonical p53 motif as well as binding strength were associated with p53-dependent transcriptional activation, but not repression, indicating that the latter was most likely indirect. p53-activated targets constituted the core of a cell type-independent response, superimposed onto a cell type-specific program. Core response genes included most of the known p53-regulated genes, as well as many new ones. Our data represent a unique characterization of the p53-regulated response to ionizing radiation in vivo. Overall design: Total RNA profiling of gene expression in the splenic B and non-B cell compartments of wild-type and Trp53-/-mice exposed to whole-body ionizing radiation by Illumina sequencing
p53 transcriptional programs in B cells upon exposure to genotoxic stress in vivo: Computational analysis of next-generation sequencing data.
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View SamplesThe tumor suppressor p53 is a transcription factor that controls the response to stress. Here, we dissected the transcriptional programs triggered upon restoration of p53 in Myc-driven lymphomas, based on the integrated analysis of p53 genomic occupancy and gene regulation. p53 binding sites were identified at promoters and enhancers, both characterized by the pre-existence of active chromatin marks. p53 recruitment at these sites was mainly mediated through protein-protein or protein-chromatin interactions and, only for a small fraction, through recognition of the 20 base-pair p53 consensus motif. At promoters, p53 binding to the consensus motif was associated with gene induction, but not repression, indicating that the latter was most likely indirect. p53 also targeted unmarked distal sites devoid of activation marks, at which binding was prevalently driven by recognition of the consensus motif. At all sites, our data highlighted a functional role for the canonical, unsplit consensus element, but did not provide evidence for p53 recruitment by split motifs. Altogether, our data highlight key features of genome recognition by p53 and provide unprecedented insight into the pathways associated with p53 re-activation and tumor regression. Overall design: Total RNA profiling of gene expression in Eµ-myc lymphomas following p53 restoration by Illumina sequencing
Genome-wide analysis of p53-regulated transcription in Myc-driven lymphomas.
Specimen part, Cell line, Subject
View SamplesThe tumor suppressor p53 can induce various biological responses. Yet it is not clear whether it is p53 in vivo promoter selectivity that triggers different transcription programs leading to different outcomes. Our analysis of genome-wide chromatin occupancy by p53 using ChIP-seq (deposited in Sequence Read Archive database as SRP007261) revealed p53 default program, i.e. the pattern of major p53-bound sites that is similar upon p53 activation by nutlin3a, RITA or 5-FU in breast cancer cells, despite different biological outcomes triggered by these compounds. Parallel analysis of gene expression allowed identification of 280 previously unknown p53 target genes, including p53-repressed AURKA. The consensus p53 binding motif was present more frequently in p53-induced, than in repressed targets, indicating different mechanisms of gene activation versus repression. We identified several possible cofactors of p53, and found that STAT3 antagonised p53-mediated repression of a subset of genes, including AURKA. Finally, we showed that the expression of the novel p53 targets correlates with p53 status and survival in breast cancer patients.
Insights into p53 transcriptional function via genome-wide chromatin occupancy and gene expression analysis.
Cell line, Treatment
View SamplesMutant p53 proteins, resulting from the missense mutations of the TP53 tumor suppressor gene, possess gain-of-function activities and are among the most robust oncoproteins in human tumors. They are potentially important therapeutic targets. No studies to date have distinguished common, therapeutically relevant mutant p53 gain-of-function effects from effects specific to different mutant variants and cell backgrounds. here we performed RNA-seq analysisin MDA-MB-231 (R280K) upon silencing TP53 or the control siRNA. Overall design: MDA-MB-231 (R280K) cell line was transfected with control or p53 siRNA.So The study comprises one experimental cell line,in triplicate.
Proteasome machinery is instrumental in a common gain-of-function program of the p53 missense mutants in cancer.
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View SamplesThis study sought to evaluate the effects of dietary MeHg exposure on adult female yellow perch (Perca flavescens) and zebrafish (Danio rerio) reproduction by relating controlled exposures with subsequent reproductive effects. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, and the use of zebrafish allowed for a detailed analysis of the molecular effects of MeHg. MeHg exposures at environmentally relevant levels were done in zebrafish for a full life cycle, mimicking a realistic exposure scenario, and in adult yellow perch for twenty weeks, capturing early seasonal ovarian development. In zebrafish, several genes involved in reproductive processes were shown to be dysregulated by RNA-seq and QPCR, but no significant phenotypic or physiological changes were observed with ovarian staging, fecundity, or embryo mortality. Yellow perch did not appear to be affected by MeHg, either at a molecular level, as assessed by QPCR of eight genes in the pituitary, liver, and ovary tissue, or a physiological level, as seen with ovarian somatic index, circulating estradiol, and ovarian staging. Lack of impact in yellow perch limits the usefulness of zebrafish as a model and suggests that the reproductive sensitivity to environmentally relevant levels of MeHg differs between yellow perch and zebrafish. Overall design: 12 samples of total RNA isolated from adult zebrafish ovaries were analyzed. Each exposure group (1, 3, and 10 ppm MeHg) had three replicates, as did the vehicle control. Each sample was comprised of pooled total RNA of up to 6 individual fish.
Female reproductive impacts of dietary methylmercury in yellow perch (Perca flavescens) and zebrafish (Danio rerio).
No sample metadata fields
View SamplesThe objective was to identify the molecular mechanisms responsible for in vitro and in vivo efficacy of an anti-MYCN peptide nucleic acid on a preclinical model of alveolar rhabdomyosarcoma. Cells treated with a anti-MYCN PNA exhibit growth arrest and apoptosis, and in vivo tumor growth is blocked.
Antitumor activity of sustained N-myc reduction in rhabdomyosarcomas and transcriptional block by antigene therapy.
No sample metadata fields
View SamplesActivity-dependent transcriptional profiling was performed in the basolateral amygdala in order to identify unique genetic markers for functionally distinct neuronal populations
Antagonistic negative and positive neurons of the basolateral amygdala.
No sample metadata fields
View SamplesWe have analyzed RNA-seq data to identify A-to-I editing sites in two groups of samples: one group isolated from human U87 cell line expressing an active ADAR3 mutant while the other isolated from U87 cell line expressing the inactive counterpart of the ADAR3 mutant. We compared these two groups of samples and identified sites whose editing levels are higher in the first group than in the second group. Overall design: Examine A-to-I editing sites in two group of samples.
RNA binding candidates for human ADAR3 from substrates of a gain of function mutant expressed in neuronal cells.
Specimen part, Disease, Disease stage, Subject
View SamplesThe purpose of this study was to identify molecular alterations potentially involved in predisposition to adnexal serous carcinoma (SerCa) in the non-malignant fallopian tube epithelium (FTE) of BRCA1/2-mutation carriers, given recent evidence implicating the distal FTE as a common source for SerCa.
Gene expression profiles of luteal phase fallopian tube epithelium from BRCA mutation carriers resemble high-grade serous carcinoma.
Age
View SamplesMiRNAs are essential mediators of many biological processes. The aim of this study was to investigate the dynamics of miRNA-mRNA regulatory networks during exercise and subsequent recovery period.
Dynamically regulated miRNA-mRNA networks revealed by exercise.
Sex, Age
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