This study has examined the molecular mechanisms underlying sensitivity of sarcomas to Nutlin-3a, a non-genotoxic activator of the p53 pathway. Human patient material was collected immediately following surgical resection, dissected into small pieces and ex planted onto gelatin sponges immersed in media containing either vehicle control or Nutlin-3a (10uM and/or 50uM) for 48 hours.
Nutlin-3a efficacy in sarcoma predicted by transcriptomic and epigenetic profiling.
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View SamplesRNA-directed DNA methylation (RdDM) is a transcriptional silencing mechanism mediated by small and long noncoding RNAs produced by the plant-specific RNA polymerases Pol IV and Pol V, respectively. Through a chemical genetics screen with a luciferase-based DNA methylation reporter, LUCL, we found that camptothecin, a compound with anti-cancer properties that targets DNA topoisomerase 1a (TOP1a) was able to de-repress LUCL by reducing its DNA methylation and H3K9 dimethylation (H3K9me2) levels. Further studies with Arabidopsis top1a mutants showed that TOP1a promotes RdDM by facilitating the production of Pol V-dependent long non-coding RNAs, AGONAUTE4 recruitment and H3K9me2 deposition at transposable elements (TEs). Overall design: 5 small RNA libraries were sequenced
DNA topoisomerase 1α promotes transcriptional silencing of transposable elements through DNA methylation and histone lysine 9 dimethylation in Arabidopsis.
Specimen part, Subject
View SamplesTruncating mutations of CHD8, encoding a chromodomain helicase, and of many other genes with diverse functions, are strong-effect risk factors for autism spectrum disorder (ASD), suggesting multiple mechanisms of pathogenesis. We explored the transcriptional networks that CHD8 regulates in neural progenitor cells (NPCs) by reducing its expression and then integrating transcriptome sequencing (RNA-seq) with genome-wide CHD8 binding (ChIP-seq). Suppressing CHD8 to levels comparable with loss of a single allele caused altered expression of 1,756 genes, 64.9% of which were up-regulated. CHD8 showed widespread binding to chromatin, with 7,324 replicated sites that marked 5,658 genes. Integration of these data suggests that a limited array of direct regulatory effects of CHD8 produced a much larger network of secondary expression changes. Genes indirectly down-regulated (i.e., without CHD8 binding sites) reflect pathways involved in brain development, including synapse formation, neuron differentiation, cell adhesion, and axon guidance, whereas CHD8-bound genes are strongly associated with chromatin modification and transcriptional regulation. Genes associated with ASD were strongly enriched among indirectly down-regulated loci (p = 1.01x10-9) and CHD8-bound genes (p = 4.34x10-3), which align with previously identified co-expression modules during fetal development. We also find an intriguing enrichment of cancer related gene-sets among CHD8-bound genes (p < 1.9x10-11). In vivo suppression of chd8 in zebrafish produced macrocephaly comparable to that of humans with inactivating mutations. These data indicate that heterozygous disruption of CHD8 precipitates a network of gene expression changes involved in neurodevelopmental pathways in which many ASD-associated genes may converge on shared mechanisms of pathogenesis. Overall design: RNA-seq in NPCs treated with shRNAs targeting CHD8. For controls, NPCs were treated with shRNAs targeting GFP and LacZ. Infection and sequencing was carried out in two separate batches, with one GFP and one LacZ sample in each batch. All samples were sequenced in two technical replicates.
CHD8 regulates neurodevelopmental pathways associated with autism spectrum disorder in neural progenitors.
No sample metadata fields
View Samplesp63 mutations have been associated with several human hereditary disorders characterized by ectodermal dysplasia such as EEC syndrome, ADULT syndrome and AEC syndrome . The location and functional effects of the mutations that underlie these syndromes reveal a striking genotype-phenotype correlation. Unlike EEC and ADULT that result from missense mutations in the DNA-binding domain of p63, AEC is solely caused by missense mutations in the SAM domain of p63. We report a study on the TAp63a isoform, the first to be expressed during development of the embryonic epithelia, and on its naturally occurring Q540L mutant derived from an AEC patient. To assess the effects of the Q540L mutation, we generated stable cell lines expressing TAp63a wt, DeltaNp63 alpha or the TAp63 alpha-Q540L mutant protein and used them to systematically compare the cell growth regulatory activity of the mutant and wt p63 proteins and to generate, by microarray analysis, a comprehensive profile of differential gene expression. We found that the Q540L substitution impairs the transcriptional activity of TAp63a and causes misregulation of genes involved in the control of cell growth and epidermal differentiation.
The Hay Wells syndrome-derived TAp63alphaQ540L mutant has impaired transcriptional and cell growth regulatory activity.
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View SamplesThe gene expression of mice with osteoblast-specific beta-catenin activation or FoxO1 deactivation are each compared to that of Wt.
Leukaemogenesis induced by an activating β-catenin mutation in osteoblasts.
Sex, Specimen part
View SamplesOchratoxin A gene expression profiling in liver and kidney, with time points of exposure from 7 days to 12 motnhs
A toxicogenomics approach to identify new plausible epigenetic mechanisms of ochratoxin a carcinogenicity in rat.
No sample metadata fields
View SamplesEwing's Sarcoma cell lines were made resistant to different IGF-1R drugs to investigate mechanisms and pathways modulated by the resistance.
Identification of common and distinctive mechanisms of resistance to different anti-IGF-IR agents in Ewing's sarcoma.
Cell line
View SamplesAnalysis of expression changes in renal collecting duct epithelial cells by adenoviral mediated Krppel like transcription factor 5 (KLF5) overexpression. KLF5 is a key regulator of static and inflammatory stage in renal collecting duct epithelial cells. We thought these results provide insights into downstream genes of KLF5 in renal collecting duct epithelial cells.
Renal collecting duct epithelial cells regulate inflammation in tubulointerstitial damage in mice.
Specimen part, Cell line
View SamplesPhotoreceptor disorders are collectively known as retinal degeneration (RD), and include retinitis pigmentosa (RP), cone-rod dystrophy and age related macular degeneration (AMD). These disorders are largely genetic in origin; individual mutations in any one of >200 genes cause RD, making mutation specific therapies prohibitively expensive. A better treatment plan, particularly for late stage disease, may involve stem cell transplants into the photoreceptor or ganglion cell layers of the retina. Stem cells from young mouse retinas can be transplanted, and can form photoreceptors in adult retinas. These cells can be grown in tissue culture, but can no longer form photoreceptors. We have used microarrays to investigate differences in gene expression between cultured retinal progenitor cells (RPCs) that have lost photoreceptor potential, postnatal day 1 (pn1) retinas and the postnatal day 5 (pn5) retinas that contain transplantable photoreceptors. We have also compared FACS sorted Rho-eGFP expressing rod photoreceptors from pn5 retinas with Rho-eGFP negative cells from the same retinas. We have identified over 300 genes upregulated in rod photoreceptor development in multiple comparisons, 37 of which have been previously identified as causative of retinal disease when mutated. It is anticipated that this research should bring us closer to growing photoreceptors in culture and therefore better treatments for RD. This dataset is also a resource for those seeking to identify novel retinopathy genes in RD patients.
Gene expression changes during retinal development and rod specification.
No sample metadata fields
View SamplesInsulators delimit independent transcriptional domains within genomes by constraining enhancer and silencer action. These transcriptional effects depend upon DNA recognition by insulator binding proteins that recruit partners that protect against inappropriate long range modulation of non-target promoters. Insulator binding proteins are broadly expressed during development, with largely constitutive binding to thousands of genomic sites. Yet, tissue-specific transcriptional changes result from the loss of individual insulator binding proteins. To understand the molecular basis for such effects, we are studying the classic Drosophila insulator protein Suppressor of Hairy-wing [Su(Hw)]. Genetic studies show that loss of this broadly expressed insulator protein prevents oocyte development. To determine the basis for the block in oogenesis, we coupled transcriptional analyses in su(Hw) mutant ovaries with genome-wide definition of Su(Hw) binding in this tissue. These studies identified 71 direct targets of Su(Hw) regulation, with nearly 70% of these genes showing increased RNA accumulation when Su(Hw) is lost. Surprisingly, derepressed Su(Hw) target genes correspond to genes normally highly expressed in neural tissues, suggesting that Su(Hw) has a critical role in silencing neural genes in the ovary. Support for this postulate was obtained by genetic studies. We found that oocyte production was restored in su(Hw) mutant females that carry a deletion of one allele of the elav family RNA binding protein 9 (Rbp9) gene. These su(Hw) null oocytes can be fertilized, with evidence that embryos lacking Su(Hw) show compromised development. Our studies extend the known transcriptional activities of Su(Hw), indicating that Su(Hw) can function as an insulator, activator and repressor, the latter function being essential for oogenesis. These findings highlight that insulator proteins are versatile transcriptional regulatory proteins, suggesting that tissue specific contributions to transcription result from direct regulation of individual genes.
The insulator protein Suppressor of Hairy-wing is an essential transcriptional repressor in the Drosophila ovary.
Specimen part
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