The SV40 large (LT) and small (st) antigens are produced from a single alternatively spliced pre-mRNA, that when co-expressed, transform a variety of cells in vitro and in vivo. However, 17kT, a relatively uncharacterized third protein that is co-linear with LT for the first 131 amino acids, is also produced from the early viral pre-mRNA by removal of an additional intron from the LT transcript. Here we report a line of transgenic mice expressing a liver-specific dox-inducible viral transcript that fails to yield any detectable LT protein, yet produces abundant 17kT. Comparative analysis of livers of transgenic mice expressing either 17kT or LT demonstrates that while 17kT is a potent stimulator of cell proliferation, it is ineffective at inducing liver tumor development, due in part, to the failure of 17kT to effectively induce the expression of growth regulators and reactivate expression of imprinted and developmentally regulated hepatic genes. These studies highlight key functional differences between LT and 17kT in their ability to transform quiescent primary epithelial cells in vivo, and demonstrate how specific functional domains within LT impact cell-specific gene expression to promote oncogenesis.
Comparative analysis of SV40 17kT and LT function in vivo demonstrates that LT's C-terminus re-programs hepatic gene expression and is necessary for tumorigenesis in the liver.
Sex, Specimen part
View SamplesDEAD-box RNA helicases eIF4A and Ded1 are believed to promote translation initiation by resolving mRNA secondary structures that impede ribosome attachment at the mRNA 5' end or subsequent scanning of the 5'UTR, but whether they perform distinct functions or act redundantly in vivo is poorly understood. We compared the effects of mutations in Ded1 or eIF4A on global translational efficiencies (TEs) in yeast by ribosome footprint profiling. Despite similar reductions in bulk translation, inactivation of a cold-sensitive Ded1 mutant substantially reduced the TEs of >600 mRNAs, whereas inactivation of a temperature-sensitive eIF4A mutant yielded <40 similarly impaired mRNAs. The broader requirement for Ded1 did not reflect more pervasive secondary structures at low temperature, as inactivation of temperature-sensitive and cold-sensitive ded1 mutants gave highly correlated results. Interestingly, Ded1-dependent mRNAs exhibit greater than average 5'UTR length and propensity for secondary structure, implicating Ded1 in scanning though structured 5' UTRs. Reporter assays confirmed that cap- distal stem-loop insertions increase dependence on Ded1 but not eIF4A for efficient translation. While only a small fraction of mRNAs is strongly dependent on eIF4A, this dependence is significantly correlated with requirements for Ded1 and 5'UTR features characteristic of Ded1- dependent mRNAs. Our findings suggest that Ded1 is critically required to promote scanning through secondary structures within 5'UTRs; and while eIF4A cooperates with Ded1 in this function, it also promotes a step of initiation common to virtually all yeast mRNAs. Overall design: We compared the effects of mutations in Ded1 or eIF4A on global translational efficiencies (TEs) in yeast by ribosome footprint profiling.The study includes 32 samples, comprised of 16 mRNA-Seq samples and 16 ribosome footprint profiling samples, derived from biological replicates of 3 mutant strains, ded1-cs, ded1-ts and tif1-ts, and the corresponding wild-type strains. The tif1-ts mutant and its wild-type counterpart were analyzed at 30°C and 37°C.
Functional interplay between DEAD-box RNA helicases Ded1 and Dbp1 in preinitiation complex attachment and scanning on structured mRNAs in vivo.
Subject
View SamplesA delay in the mammalian inflammatory response is a prominent feature of infection with Yersinia pestis, the agent of bubonic and pneumonic plague. Y. pestis factors have been identified that either do not stimulate a normal inflammatory response, or actively suppress it. Prominent among these are components of the Type III secretion system that is encoded on the Yersinia virulence plasmid (pYV). We used a rat model of bubonic plague to characterize the kinetics and extent of the mammalian transcriptomic response to infection with wild-type or pYV-negative Y. pestis in the draining lymph node. Remarkably, dissemination and multiplication of wild-type Y. pestis during the bubonic stage of disease did not induce any detectable gene expression response by host lymph node cells. This was followed, however, by an extensive transcriptomic response, including upregulation of several cytokine, chemokine, and other immune response genes, after systemic spread during septicemic plague. Matched lymph node samples used for histopathology and extracellular cytokine measurements, combined with the microarray data set, broadly outlined the mammalian immune response to Y. pestis and how it is influenced by pYV-encoded factors. The results indicate that both WT and pYV Y. pestis induce primarily a Th17 response, and not a Th1 or Th2 response. In the absence of pYV, a sustained recruitment of polymorphonuclear leukocytes, the major Th17 effector cell, to the lymph node resulted in clearance of infection. Thus, the ability to counteract a Th17- driven PMN response in the lymph node appears to be a major function of the Y. pestis virulence plasmid. In contrast, classic markers of the proinflammatory response and macrophage activation, such as TNF- and IFN-, were not induced at all by pYV Y. pestis, and appeared only late in infection with WT Y. pestis.
Transcriptomic and innate immune responses to Yersinia pestis in the lymph node during bubonic plague.
Sex, Specimen part, Treatment, Time
View SamplesThe transcriptional data from an integrative analysis of transcriptional and metabolic stress responses that provides a more complete understanding of the mechanisms by which genetic regulatory circuits mediate metabolic phenotype.
Linking high-resolution metabolic flux phenotypes and transcriptional regulation in yeast modulated by the global regulator Gcn4p.
No sample metadata fields
View SamplesAlveolar rhabdomyosarcoma (aRMS) is a soft tissue sarcoma associated with the skeletal muscle lineage. The majority of aRMS tumors express the fusion protein PAX3-FOXO1 (PF), which has proven chemically intractable. As such, we identified proteins downstream from or cooperate with PF to support tumorigenesis, including SFRP3 (FRZB). Suppression of SFRP3 using lentivirally transduced shRNAs inhibits cell growth in vitro and tumor growth in vivo. This study aims to identify the genetic changes that underlie the SFRP3 suppression-mediated decreased cell growth. We analyzed changes using Gene Ontology (GO) enrichment and found the induced genes were enriched in striated muscle development/differentiation. In contrast, the repressed genes were enriched in response to stimulus and cell cycle/mitosis genes. We also observed as expected downregulation of SFRP3 (FRZB) but also downregulation of Wnt pathway-repressing genes such as CTBP2 (a transcriptional repressor of TCF, similar to CTBP1 ) and NAV2 (which is downstream from APC). Conversely, we noted upregulation of genes including CCND1 (cyclin D1) and SNAI2 (SLUG), both Wnt signaling target genes and WNT6, which is known to inhibit myoblast proliferation but induce myoblast elongation.
Secreted Frizzled-Related Protein 3 (SFRP3) Is Required for Tumorigenesis of PAX3-FOXO1-Positive Alveolar Rhabdomyosarcoma.
Disease, Cell line, Treatment
View SamplesTo investigate transcriptional differences between HCM and WT cells Overall design: Examination of HCM vs WT Cells, with 3 replicates of each sample
A Contraction Stress Model of Hypertrophic Cardiomyopathy due to Sarcomere Mutations.
Specimen part, Disease, Disease stage, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MEK inhibitors activate Wnt signalling and induce stem cell plasticity in colorectal cancer.
Specimen part, Treatment
View SamplesAnalysis of differentiating LSD1-KD C2C12 myoblasts. We found LSD1 is an important regulator of oxidative phenotypes in skeletal muscle cells.
LSD1 mediates metabolic reprogramming by glucocorticoids during myogenic differentiation.
Specimen part, Cell line
View SamplesAnalysis of differentiating C2C12 myoblasts treated with two LSD1 specific inhibitors. We found LSD1 is an important regulator of oxidative phenotypes in skeletal muscle cells. Results provide insight into the molecular mechanisms underlying roles of LSD1 in myocytes.
LSD1 mediates metabolic reprogramming by glucocorticoids during myogenic differentiation.
Specimen part, Cell line
View SamplesDuring cold acclimation plants increase their freezing tolerance in response to low non-freezing temperatures. This is accompanied by many physiological, biochemical and molecular changes that have been extensively investigated. In addition, many cold acclimated plants become more freezing tolerant during exposure to mild, non-damaging sub-zero temperatures. There is hardly any information available about the molecular basis of this adaptation. However, Arabidopsis thaliana is among the species that acclimate to sub-zero temperatures. This makes it possible to use the molecular and genetic tools available in this species to identify components of sub-zero signal transduction and acclimation. Here, we have used microarrays and a qRT-PCR primer platform covering 1880 genes encoding transcription factors to monitor changes in gene expression in the accessions Columbia-0, Rschew and Tenela during the first three days of sub-zero acclimation at -3C. The results indicate that gene expression during sub-zero acclimation follows a tighly controlled time-course. Especially AP2/EREBP and WRKY transcription factors may be important regulators of sub-zero acclimation, although the CBF signal transduction pathway seems to be less important during sub-zero than during cold acclimation. Globally, we estimate that approximately 5% of all Arabidopsis genes are regulated during sub-zero acclimation. Particularly photosynthesis-related genes were down-regulated and genes belonging to the functional classes of cell wall biosynthesis, hormone metabolism and RNA regulation of transcription were up-regulated. Collectively, these data provide the first global analysis of gene expression during sub-zero acclimation and allow the identification of candidate genes for forward and reverse genetic studies into the molecular mechanisms of sub-zero acclimation.
Global changes in gene expression, assayed by microarray hybridization and quantitative RT-PCR, during acclimation of three Arabidopsis thaliana accessions to sub-zero temperatures after cold acclimation.
Specimen part, Time
View Samples