This SuperSeries is composed of the SubSeries listed below.
No associated publication
Specimen part
View SamplesBACKGROUND:Dynamic transcriptional regulation is critical for an organism's response to environmental signals and yet remains elusive to capture. Such transcriptional regulation is mediated by master transcription factors (TF) that control large gene regulatory networks. Recently, we described a dynamic mode of TF regulation named "hit-and-run". This model proposes that master TF can interact transiently with a set of targets, but the transcription of these transient targets continues after the TF dissociation from the target promoter. However, experimental evidence validating active transcription of the transient TF-targets is still lacking.
"Hit-and-Run" transcription: de novo transcription initiated by a transient bZIP1 "hit" persists after the "run".
Specimen part
View SamplesLoss of Tet1 expression causes global 5mC and 5hmC changes in stem and progenitor cells in mice and causes enhanced Pro-B cell self-renewal, increased DNA damage and B-lymphomageneis. In this study we performed microarray analysis of total LSK cells from WT and Tet1 KO mice. These results revealed that genes regulated byTet1 in LSKs included Histones, DNA repair enzymes and B-lineage specific factors.
No associated publication
Specimen part
View SamplesIn all animals, the initial events of embryogenesis are controlled by maternal gene products that are deposited into the developing oocyte. At some point after fertilization, control of embryogenesis is transferred to the zygotic genome in a process called the maternal to zygotic transition (MZT). During this time maternal RNAs are degraded and zygotic RNAs are transcribed1. A long standing question has been, what factors regulate these events? The recent findings that microRNAs and Smaugs mediate maternal transcript degradation brought new life to this old problem2,3, however, the transcription factors that activate zygotic gene expression remained elusive. A clue came from the finding that many early zygotic genes in Drosophila share a cis-regulatory heptamer motif, CAGGTAG and related sequences, collectively referred to as TAG-team sites4,5. We asked whether there was a dedicated transcription factor that interacts with these sites to activate early genes. Here we report the discovery of a zinc-finger protein, Zelda (Zld) that binds specifically to TAG-team sites, and is capable of activating transcription in transient transfection assays. Mutant embryos lacking zld are defective in the cellularization process, and fail to activate the transcription of many early zygotic genes involved in cellularization, sex determination, and dorsoventral patterning. Global expression profiling confirmed that Zld plays a key role in the activation of the early zygotic genome, and suggests that Zld may also play a role in maternal RNA degradation during the MZT since many RNAs are up-regulated in the absence of Zld.
No associated publication
No sample metadata fields
View SamplesIt is widely believed that the carcinogenic action of ionizing radiation is due to targeted DNA damage and resulting mutations, but there is also substantial evidence that non-targeted radiation effects alter epithelial phenotype and the stromal microenvironment. Activation of transforming growth factor 1 (TGF) is a non-targeted radiation effect that mediates cell fate decisions following DNA damage and regulates microenvironment composition; it could either suppress or promote cancer. We asked if such non-targeted radiation effects contribute to carcinogenesis by using a novel radiation chimera model. Unirradiated Trp53 null mammary epithelium was transplanted to the mammary stroma, previously divested of endogenous epithelia, of mice previously exposed to a single low (10 -100 cGy) radiation dose. By 300 days, 100% of transplants in irradiated hosts at either 10 or 100 cGy had developed Trp53 null breast carcinomas compared to 54% in unirradiated hosts. Tumor growth rate was also increased by high, but not low, dose host irradiation. In contrast, irradiation of Tgfb1 heterozygote mice prior to transplantation failed to decrease tumor latency, or increase growth rate at any dose. Host irradiation significantly reduced the latency of invasive ductal carcinoma compared to spindle cell carcinoma. However, irradiation of either host genotype significantly increased the frequency of estrogen receptor negative tumors. These data demonstrate two concepts critical to understanding radiation risks. First, non-targeted radiation effects can significantly promote the frequency and alter the features of epithelial cancer. Second, radiation-induced TGF activity is a key mechanism of tumor promotion.
No associated publication
Age, Specimen part
View SamplesBackground. Chronic renal failure is characterized by progressive renal scarring and accelerated cardiovascular disease. In animal models, this is thought to be due to non-dialyzable uremic toxins small, protein-bound molecules normally secreted via Organic Anion Transporters (OATs) in the proximal renal tubule,rather than filtered at the glomerulus. The best studied of these is indoxyl sulfate (IS).
No associated publication
Specimen part
View SamplesNonsense-mediated RNA decay (NMD) is regulated by a variety of cellular stresses. We expose U2OS cells to several stresses and assess RNA expression in the absence of transcription (i.e. stability). These studies identify transcripts that are stabilized by the physiological inhibition of NMD.
Inhibition of nonsense-mediated RNA decay by the tumor microenvironment promotes tumorigenesis.
Specimen part, Cell line, Treatment, Time
View SamplesACSL4 expression appears to be inversely associated with steroid hormone and growth factor receptor expression in breast cancer and positively correlated with an aggressive breast cancer phenotype. Neither MCF-7 nor SKBr3 cells normally express ACSL4, and when manipulated to do so, develop basal-like characteristics, including increased proliferation, migration and anchorage independent growth. We used an Affymetrix array platform to assess changes in individual gene expression as a function of conditional and stable expression of ACSL4 in MCF-7 and SKBr3 cells.
No associated publication
Specimen part, Disease, Disease stage, Cell line, Treatment
View SamplesGenome-wide profiling establishes that human cytomegalovirus (HCMV) exerts an extensive, unforeseen level of specific control over which cellular mRNAs are recruited to or excluded from polyribosomes.
Global reprogramming of the cellular translational landscape facilitates cytomegalovirus replication.
Specimen part, Disease, Treatment
View SamplesRecurrent somatic mutations in TET2 and in other genes that regulate the epigenetic state have been identified in patients with myeloid malignancies and in other cancers. However, the in vivo effects of Tet2 loss have not been delineated. We report here that Tet2 loss leads to increased stem-cell self-renewal and to progressive stem cell expansion. Consistent with human mutational data, Tet2 loss leads to myeloproliferation in vivo, notable for splenomegaly and monocytic proliferation. In addition, haploinsufficiency for Tet2 confers increased self-renewal and myeloproliferation, suggesting that the monoallelic TET2 mutations found in most TET2-mutant leukemia patients contribute to myeloid transformation. This work demonstrates that absent or reduced Tet2 function leads to enhanced stem cell function in vivo and to myeloid transformation.
Tet2 loss leads to increased hematopoietic stem cell self-renewal and myeloid transformation.
Specimen part
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