The analysis of several mammalian genomes has revealed between 20,000 to 30,000 genes in each genome, a number that may seem hard to reconcile with the large number of cell types and complex functions of these organisms. The solution to this paradox partly lies in the large array of transcripts that each gene can potentially generate through usage of alternative promoters and the variable levels of transcripts that each gene produces in different tissues and cell types. Thus, in order to understand the mechanisms that control diverse patterns of gene expression in mammals, it is necessary to accurately define the active promoters and monitor their cell or tissue-dependent activity. Previous high throughput strategies for assaying tissue-specific gene expression have primarily relied on measurements of steady-state transcript levels by microarrays or tag sequencing. Here, we employ a new experimental strategy to identify and characterize tissue specific promoters by integrating genome-wide maps of RNA polymerase II (Pol II) binding, chromatin modifications and gene expression profiles. We applied this strategy to mouse embryonic stem cells (mES), and adult brain, heart, kidney, and liver. Our results delineated 24,363 Pol II binding sites throughout the genome, 91% of which correspond to 5 end annotation based on known transcripts and cap-analysis of gene expression (CAGE) and can be regarded as promoters. A majority of these experimentally defined promoters are active in all tissues, while only 4,396 can be characterized as tissue-specific using a quantitative measure of Pol II occupancy. In general, Pol II occupancy at these tissue specific promoters is correlated with the presence of active histone modification marks. However, a set of mES- specific promoters display persistent levels of H3K4me3 in non-ES tissues despite undetectable Pol II binding and transcript. Broadly, our results expand the knowledge of tissue-specific mammalian genes and provide a resource for understanding the transcriptional programs in mammalian development and differentiation.
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Genomic binding of PAX8-PPARG fusion protein regulates cancer-related pathways and alters the immune landscape of thyroid cancer.
Specimen part, Treatment
View SamplesPAX8-PPARG fusion protein (PPFP) results from a t(2;3)(q13;p25) chromosomal translocation, is found in 30% of follicular thyroid carcinomas, and demonstrates oncogenic capacity in transgenic mice. A PPARG ligand, pioglitazone, is highly therapeutic in mice with PPFP thyroid carcinoma. We used our previously characterized transgenic mouse model of PPFP thyroid carcinoma to identify PPFP binding sites in vivo using ChIP-seq, and to identify genes and pathways regulated by PPFP with and without pioglitazone treatment via integration with RNA-seq and Affymetrix microarray data. This submission contains the Affymetrix microarray data. PPFP and pioglitazone regulated genes involved in lipid and fatty acid metabolism, ribosome function, immune processes, cell death and other cancer-related processes. The RNA-seq data yielded similar findings.
Genomic binding of PAX8-PPARG fusion protein regulates cancer-related pathways and alters the immune landscape of thyroid cancer.
Specimen part, Treatment
View SamplesConventional biochemical and molecular techniques identified previously several genes whose expression is regulated by the aryl hydrocarbon receptor (AHR). We sought to map the complete spectrum of AHR-dependent genes in male adult liver using expression arrays to contrast mRNA profiles in Ahr-null mice (Ahr/) with those in mice with wild-type AHR (Ahr+/+). Transcript profiles were determined both in untreated mice and in mice treated 19 h earlier with 1000 g/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Expression of 456 ProbeSets was significantly altered by TCDD in an AHR-dependent manner, including members of the classic AHRE-I gene battery, such as Cyp1a1, Cyp1a2, Cyp1b1, and Nqo1. In the absence of exogenous ligand, AHR status alone affected expression of 392 ProbeSets, suggesting that the AHR has multiple functions in normal physiology. In Ahr/ mice, only 32 ProbeSets exhibited responses to TCDD, indicating that the AHR is required for virtually all transcriptional responses to dioxin exposure in liver. The flavin-containing monooxygenases, Fmo2 and Fmo3, considered previously to be uninducible, were highly induced by TCDD in an AHR-dependent manner. The estrogen receptor alpha as well as two estrogen-receptor-related genes (alpha and gamma) exhibit AHR-dependent expression, thereby extending cross-talk opportunities between the intensively studied AHR and estrogen receptor pathways. p53 binding sites are over-represented in genes down-regulated by TCDD, suggesting that TCDD inhibits p53 transcriptional activity. Overall, our study identifies a wide range of genes that depend on the AHR, either for constitutive expression or for response to TCDD.
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View SamplesDNA repair genes have been shown to be expressed in the early stages of mammalian development probably to reduce possible replication errors and genotoixc damages. Several birth defects and some cancers are due to inappropriate or defective DNA repair machinery indicating that a right activity of DNA repair genes in the early stages of fetal development are essential for an appropriate DNA function. Neuroblastoma (NB), an embryonal tumor deriving from neural crest cells (NCCs) is diagnosed in about 30% of patients within the first year of life. Moreover, several reports show that NB can be detected in foetus and in neonatal period.
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View SamplesAffymetrix Mouse Genome 430 2.0 arrays were used to measure genome-wide gene expression levels. The results show that high-risk human papillomavirus oncogenes E6 and E7 reprogram the cervical cancer microenvironment independently of and synergistically with estrogen, a critical co-factor in cervical cancer development and maintenance.
Human papillomavirus oncogenes reprogram the cervical cancer microenvironment independently of and synergistically with estrogen.
Specimen part, Treatment
View SamplesMerm1/Wbscr22 is one of genes in chromosomal region deleted in Williams-Beuren syndrome, a multisystem developmental disorder. Wbscr22 contains a nuclear localization signal and an S-adenosyl-L-methionine-dependent methyltransferase fold, but its real function is completely unknown.In this study, to examine the function, we compared the gene expression profiles between control and Merm1/Wbscr22 knock-downed tumor cells.
The novel metastasis promoter Merm1/Wbscr22 enhances tumor cell survival in the vasculature by suppressing Zac1/p53-dependent apoptosis.
Cell line, Treatment
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Activation of the aryl hydrocarbon receptor dampens the severity of inflammatory skin conditions.
Sex, Age, Specimen part, Treatment, Subject
View SamplesTarget genes of four signaling pathways (Notch, Fgf, Retinoic Acid [RA] and Wnt) are identified in the posterior presomitic mesoderm of 12 somite stage zebrafish embryos.
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Specimen part
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