TFIID is a central player in activated transcription initiation. Recent evidence suggests that the role and composition of TFIID is more diverse than previously understood. To investigate the effects of changing the composition of TFIID in a simple system we depleted TAF1 from Drosophila cells and determined the consequences on metal induced transcription at an inducible gene, Metallothionein B (MtnB). We observe a marked increase in the levels of both the mature message and pre-mRNA in TAF1 depleted cells. Under conditions of continued metal exposure, we show that TAF1 depletion increases the magnitude of the initial transcription burst, but has no effect on the timing of that burst. We also show that TAF1 depletion causes delay in the shut-off of transcription upon removal of the stimulus. Thus TAFs are involved in both establishing an upper limit of transcription during induction and efficiently turning the gene off once the inducer is removed. Using genomewide nascent-seq we identify hundreds of genes that are controlled in a similar manner indicating that the findings at this inducible gene are likely generalizable to a large set of promoters. There is a long-standing appreciation for the importance of the spatial and temporal control of transcription. Here we uncover an important third dimension of control, the magnitude of the response. Our results show that the magnitude of the transcriptional response to the same signaling event, even at the same promoter, can vary greatly depending on the composition of the TFIID complex in the cell. Overall design: Nascent RNA was sequenced from replicate samples of Drosophila S2 cells treated with double-stranded RNA directed against E. coli LacI (Control) or against Drosophlia TAF1 (experimental). Reads per kilo-base per million (RPKM) was determined for each gene and the control and experimental samples were compared to determine the genes that were affected by the depletion of TAF1.
Holo-TFIID controls the magnitude of a transcription burst and fine-tuning of transcription.
Specimen part, Subject
View SamplesApproximately 30% of women diagnosed with ERa breast cancer relapse with metastatic disease following adjuvant treatment with endocrine therapies. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain (TAD) undergoes epigenetic reprogramming in cells that develop resistance to aromatase inhibitors (AI), leading to keratin 80 (KRT80) upregulation. In agreement, an increased number of KRT80-positive cells are observed at relapse in vivo while KRT80 expression associates with poor outcome using several clinical endpoints. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 1 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion maturation and cellular stiffening, which collectively promote cancer cell invasion. Shear-wave elasticity imaging of tumors from prospectively recruited patients shows that KRT80 levels correlate with stiffer tumors in vivo. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment. Overall design: Total RNA profiling of MCF7 breast adenocarcinoma cell line and MCF7 overexpressing KRT80. Experiments were carried out in four replicates in both cell lines.
SREBP1 drives Keratin-80-dependent cytoskeletal changes and invasive behavior in endocrine-resistant ERα breast cancer.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The thrombopoietin/MPL axis is activated in the Gata1<sup>low</sup> mouse model of myelofibrosis and is associated with a defective RPS14 signature.
Sex
View SamplesMyelofibrosis (MF) is caused by genetic abnormalities involving the thrombopoietin (TPO)/MPL/JAK2 axis. Furthermore MF patients have elevated serum TPO levels. MF is also associated with reduced GATA1 content in MK suggesting that this abnormality represents a phenotypic modifier. In 2014, Dr. Crispino suggested that in MF abnormal TPO signaling induces a ribosomal deficiency hampering GATA1 mRNA translation in MK. Support for MK GATA1 deficiency as phenotypic modifier in MF was provided by the observation that mice carrying the Gata1low mutation reducing Gata1 transcription in MK develop myelofibrosis. Since reduced RBC half-life subject these mice to continuous erythroid stress, we investigated the TPO/Mpl axis in this model. In Gata1low and wild-type mice, TPO mRNA was expressed by bone marrow (BM), spleen and liver. The greatest expression (by 300-fold) was detected in liver. Gata1low livers expressed TPO mRNA levels 6-fold greater than wild-type livers. TPO protein was detected in BM, spleen, liver and peritoneum washes and plasma. The greatest levels where detected in plasma. Gata1low plasma contained TPO levels 2-fold lower than wild-type plasma, but 2-times greater than plasma from bleed wild-type mice and Mplnull mice with similar thrombocytopenia, suggesting that TPO is overproduced in Gata1low mice. JAK2 and STAT5 were easily detected in Gata1low BM bur barely detectable in wild-type BM, suggesting that in the former MPL is prompt to signaling activation. Furthermore, Gata1low LSK expressed levels of Mpl mRNA 3-times greater than wild-type cells but expressed cell-surface levels of MPL 2-times lower than wild-type cells and similar to those on LSK from TPO-treated wild-type mice, suggesting that MPL is down-modulated in Gata1low LSK. The Crispinos hypothesis that in MF activation of TPO/MPL/JAK2 induces a ribosomal deficiency hampering GATA1 mRNA translation and the realization that this axis is activated in Gata1low mice made us question the original hypothesis that reduced content of GATA1 in Gata1low MK results from deletion of lineage-specific enhancers. Microarray analyses indeed identified that Gata1low BM express a discordant ribosome signature including reduced expression of RPS24 and RPS36A, two genes mutated in Diamond Blackfan Anemia, a disease characterized by inefficient GATA1 mRNA translation. Electron microscopy identified that the cytoplasm of Gata1low MK contained poorly developed endoplasmic reticulum with rare polysomes. In conclusion, these results validate the Gata1low model as a MF model by indicating that these mice express an activated TPO/MPL axis and an abnormal ribosomal signature which may reduce efficiency of Gata1 mRNA translation.
The thrombopoietin/MPL axis is activated in the Gata1<sup>low</sup> mouse model of myelofibrosis and is associated with a defective RPS14 signature.
Sex
View SamplesMyelofibrosis (MF) is caused by genetic abnormalities involving the thrombopoietin (TPO)/MPL/JAK2 axis. Furthermore MF patients have elevated serum TPO levels. MF is also associated with reduced GATA1 content in MK suggesting that this abnormality represents a phenotypic modifier. In 2014, Dr. Crispino suggested that in MF abnormal TPO signaling induces a ribosomal deficiency hampering GATA1 mRNA translation in MK. Support for MK GATA1 deficiency as phenotypic modifier in MF was provided by the observation that mice carrying the Gata1low mutation reducing Gata1 transcription in MK develop myelofibrosis. Since reduced RBC half-life subject these mice to continuous erythroid stress, we investigated the TPO/Mpl axis in this model. In Gata1low and wild-type mice, TPO mRNA was expressed by bone marrow (BM), spleen and liver. The greatest expression (by 300-fold) was detected in liver. Gata1low livers expressed TPO mRNA levels 6-fold greater than wild-type livers. TPO protein was detected in BM, spleen, liver and peritoneum washes and plasma. The greatest levels where detected in plasma. Gata1low plasma contained TPO levels 2-fold lower than wild-type plasma, but 2-times greater than plasma from bleed wild-type mice and Mplnull mice with similar thrombocytopenia, suggesting that TPO is overproduced in Gata1low mice. JAK2 and STAT5 were easily detected in Gata1low BM bur barely detectable in wild-type BM, suggesting that in the former MPL is prompt to signaling activation. Furthermore, Gata1low LSK expressed levels of Mpl mRNA 3-times greater than wild-type cells but expressed cell-surface levels of MPL 2-times lower than wild-type cells and similar to those on LSK from TPO-treated wild-type mice, suggesting that MPL is down-modulated in Gata1low LSK. The Crispinos hypothesis that in MF activation of TPO/MPL/JAK2 induces a ribosomal deficiency hampering GATA1 mRNA translation and the realization that this axis is activated in Gata1low mice made us question the original hypothesis that reduced content of GATA1 in Gata1low MK results from deletion of lineage-specific enhancers. Microarray analyses indeed identified that Gata1low BM express a discordant ribosome signature including reduced expression of RPS24 and RPS36A, two genes mutated in Diamond Blackfan Anemia, a disease characterized by inefficient GATA1 mRNA translation. Electron microscopy identified that the cytoplasm of Gata1low MK contained poorly developed endoplasmic reticulum with rare polysomes. In conclusion, these results validate the Gata1low model as a MF model by indicating that these mice express an activated TPO/MPL axis and an abnormal ribosomal signature which may reduce efficiency of Gata1 mRNA translation.
The thrombopoietin/MPL axis is activated in the Gata1<sup>low</sup> mouse model of myelofibrosis and is associated with a defective RPS14 signature.
Sex
View SamplesMany aged individuals develop monoclonal expansions of CD8 T cells. These expansions are derived from a CD8 memory T cell that outcompetes neighboring CD8 T cells. The molecular alterations within clonal expansions that confer this competitive advantage relative to other CD8 T cells remains unknown. These microarray experiments were designed to identify genes differentially expressed in age-associated expansions of CD8 memory T cells relative to polyclonal CD8 memory T cells found in the same aged mice.
Identification of two major types of age-associated CD8 clonal expansions with highly divergent properties.
No sample metadata fields
View SamplesThe aim of this experiment was to investigate differential gene expression in splenocytes stimulated with BCG from nave and BCG vaccinated mice. The differences between nave and BCG vaccinated mice might indicate the mechanisms by which BCG vaccination confers an enhanced ability of splenocytes from BCG vaccinated mice to inhibit growth of BCG in splenocyte cultures as compared with splenocytes from naive animals.
Mycobacterial growth inhibition in murine splenocytes as a surrogate for protection against Mycobacterium tuberculosis (M. tb).
Sex, Age, Specimen part
View SamplesTransient expression of two factors, or from Oct4 alone, resulted in efficient generation of human iPSCs. The reprogramming strategy described revealed a potential transcriptional signature for human iPSCs yet retaining the gene expression of donor cells in human reprogrammed cells free of viral and transgene interference.
Transcriptional signature and memory retention of human-induced pluripotent stem cells.
Sex, Specimen part
View SamplesEthanol exposure during prenatal development causes fetal alcohol spectrum disorder (FASD), the most frequent preventable birth defect and neurodevelopmental disability syndrome. The molecular targets of ethanol toxicity during development are poorly understood. Developmental stages surrounding gastrulation are very sensitive to ethanol exposure. To understand the effects of ethanol on early transcripts during embryogenesis, we treated zebrafish embryos with ethanol during pre-gastrulation period and examined the transcripts by Affymetrix GeneChip microarray before gastrulation. We identified 521 significantly dysregulated genes, including 61 transcription factors in ethanol-exposed embryos. Sox2, the key regulator of pluripotency and early development was significantly reduced. Functional annotation analysis showed enrichment in transcription regulation, embryonic axes patterning, and signaling pathways, including Wnt, Notch and retinoic acid. We identified all potential genomic targets of 25 dysregulated transcription factors and compared their interactions with the ethanol-dysregulated genes. This analysis predicted that Sox2 targeted a large number of ethanol-dysregulated genes. A gene regulatory network analysis showed that many of the dysregulated genes are targeted by multiple transcription factors. Injection of sox2 mRNA partially rescued ethanol-induced gene expression, epiboly and gastrulation defects. Additional studies of this ethanol dysregulated network may identify therapeutic targets that coordinately regulate early development.
Embryonic ethanol exposure alters expression of sox2 and other early transcripts in zebrafish, producing gastrulation defects.
Treatment
View SamplesHuman medulloblastoma (MB) can be segregated into four major categories based on gene expression patterns: Hedgehog (HH) subtype, Wnt subtype, Group 3, and Group 4. However, they all exhibit strikingly different gene expression profiles from Atypical Teratoid/Rhabdoid Tumor (AT/RT). We re-analyzed published gene expression microarray dataset of pediatric brain tumors to identify a gene expression profile that clearly distinguished human AT/RT from human MB. We used this profile, choosing only genes that have clear murine orthologs, to compare tumors from Snf5F/Fp53L/LGFAP-Cre mice (in C57Bl/6 strain background) with MB from Ptc1+/- mice (in mixed C57Bl/6 and 129Sv strain background). Snf5F/Fp53L/LGFAP-Cre tumors are clearly very different from mouse MB and the markers that distinguish human AT/RT from human MB also distinguish the mouse tumors.
Generation of a mouse model of atypical teratoid/rhabdoid tumor of the central nervous system through combined deletion of Snf5 and p53.
No sample metadata fields
View Samples