SV40 transforms cells through the action of two oncoproteins, large T antigen and small t antigen. Small t antigen targets phosphatase PP2A, while large T antigen stimulates cell proliferation and survival by action on multiple proteins, including the tumor suppressors Rb and p53. Large T antigen also binds components of the transcription initiation complex and several transcription factors. We examined global gene expression in SV40-transformed mouse embryo fibroblasts, and in enterocytes obtained from transgenic mice. SV40 transformation alters the expression of approximately 800 cellular genes in both systems. Much of this regulation is observed in both MEFs and enterocytes and is consistent with T antigen action on the Rb-E2F pathway. However, the regulation of many genes is cell-type specific, suggesting that unique signaling pathways are activated in different cell types upon transformation, and that the consequences of SV40 transformation depends on the type of cell targeted.
Cell-type specific regulation of gene expression by simian virus 40 T antigens.
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View SamplesThe E2F family consists of transcriptional repressors and activators that control cell proliferation. In the classic paradigm of cell cycle regulation, the three activators, E2F1, E2F2 and E2F3, are invariably depicted as the final components of a CDK/Rb signaling cascade that executes the transcriptional program necessary to commit cells to enter S phase.
Cell proliferation in the absence of E2F1-3.
Specimen part
View SamplesThe retinoblastoma protein (pRB) is best known for regulating cell proliferation through E2F transcription factors. In this report we investigate the properties of a targeted mutation that disrupts pRB interactions with the transactivation domain of E2Fs. Mice that carry this mutation endogenously (Rb1G) are defective in regulating E2F target genes. Surprisingly, cell cycle regulation in Rb1G/G MEFs strongly resembles that of wild type. In a serum deprivation induced cell cycle exit, Rb1G/G MEFs display a similar magnitude of E2F target gene derepression as Rb1-/-, even though Rb1G/G cells exit the cell cycle normally. Interestingly, cell cycle arrest in Rb1G/G MEFs is responsive to p16 expression, indicating that the G-pRB protein can be activated in G1 to arrest proliferation through non-E2F mechanisms. Some Rb1G/G mice die neonatally with a muscle degeneration phenotype, while the others live a normal lifespan with no evidence of spontaneous tumor formation. Histological analysis reveals discrete examples of hyperplasia in the mammary epithelium, but most tissues appear normal while being accompanied by derepression of pRB regulated E2F targets. This suggests that non-E2F, pRB dependent pathways may have a more relevant role in proliferative control than previously identified.
A retinoblastoma allele that is mutated at its common E2F interaction site inhibits cell proliferation in gene-targeted mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Redeployment of Myc and E2f1-3 drives Rb-deficient cell cycles.
Specimen part
View SamplesCombined ablation of Myc and E2f1-3 results in disruption of crypt-villus integrity in the small intestine due to a S-G2 cell cycle blockade.
Redeployment of Myc and E2f1-3 drives Rb-deficient cell cycles.
Specimen part
View SamplesLoss of Myc corrects abrrant transcription in Rb KO villi, while these genetic manipulation does not lead to major gene expression changes in crypts.
Redeployment of Myc and E2f1-3 drives Rb-deficient cell cycles.
Specimen part
View SamplesYerba mate (YM) has been shown to have anti-inflammatory properties in several studies. However, this effect has been found mainly in obesity-related in inflammation. The aim of this work was to study the effect of YM in cultured peripheral blood mononuclear cells to see whether it has anti-inflammatory properties. We stimulated peripheral blood mononuclear cells in vitro with phitohemaglutinin in the presence of yerba mate and determined their activation measuring the the expression of CD25 by flow cytometry. We observed that YM treatment produced a dose-dependent reduction in PBMC activation (CD25 positive cells) when they were stimulated with PHA. This effect was also observed in T cells (CD3 positive) subpopulation. Microarray analysis revealed the differential expression of 128 genes in YM-treated cells. According to a protein-protein interaction database, these genes were highly connected and they are involved in inflammatory response. In summary, it was demonstrated that YM produces a reduction in the amount of activated cells under the stimulation of PHA. Therefore, it might be used in diseases with an inflammatory component.
Yerba mate (Ilex paraguariensis) inhibits lymphocyte activation in vitro.
Sex, Specimen part
View SamplesWhole-genome expression of peripheral blood leukocytes was measured in 22 patients and 24 controls using the Human Gene 1.0 ST array by Affymetrix
Transcriptomic profile reveals gender-specific molecular mechanisms driving multiple sclerosis progression.
Sex, Age, Specimen part, Disease
View SamplesC. elegans totalRNA profiles of worms treated with RNAi for different Integrator complex genes or L4440 (Control). Worms were grown at 15ºC and samples were taken six days after silencing Overall design: C. elegans totalRNA profiles of worms treated with RNAi for different Integrator complex genes or L4440 (Control). Three replicates per sample. Deep sequencing in Illumina HiSeq1500.
Disruption of the Caenorhabditis elegans Integrator complex triggers a non-conventional transcriptional mechanism beyond snRNA genes.
Subject
View SamplesThe transcriptomes of model organisms have been defined under specific laboratory growth conditions. The standard protocol for Caenorhabditis elegans growth and maintenance is 20ºC on an Escherichia coli diet. Temperatures ranging from 15ºC to 25ºC or feeding with other species of bacteria are considered physiological lab conditions, but the effect of these conditions on the worm transcriptome have not been well characterized. Here, we compare the global patterns of gene expression for the reference Caenorhabditis elegans strain (N2) grown at 15oC, 20oC, and 25oC on two different diets, Escherichia coli and Bacillus subtilis. When C. elegans were fed E. coli and the growth temperature was increased, we observed an enhancement of defense response pathways and down-regulation of genes associated with metabolic functions. However, when C. elegans were fed B. subtilis and the growth temperature was increased, the nematodes exhibited a decrease in defense response pathways and an enhancement of expression of genes associated with metabolic functions. Our results show that C. elegans undergo significant metabolic and defense response changes when the maintenance temperature fluctuates within the physiologically accepted experimental range and that the degree of pathogenicity of the bacterial diet can further alter the worm transcriptome. Overall design: C. elegans mRNA profiles at different temperatures and feeding in six samples, three replicates per sample. Deep sequencing in Illumina HiSeq2500.
Effect of the diet type and temperature on the <i>C. elegans</i> transcriptome.
Subject
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