Differential gene expression profiles were observed in response to Hras in either wild-type or Ppar-beta null primary keratinocytes and differentail gene edxpression profiles by GW0742 were only found in wild-type keratinocytes.
Peroxisome proliferator-activated receptor β/δ cross talks with E2F and attenuates mitosis in HRAS-expressing cells.
Specimen part
View SamplesThe human and mouse aryl hydrocarbon receptor (hAHR and mAHRb) share limited (58%) transactivation domain sequence identity. Compared to the mAHRb allele, the hAHR displays 10-fold lower relative affinity for prototypical ligands such as 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD). However, in previous studies we have demonstrated that the hAHR can display a higher relative ligand binding affinity than the mAHRb for specific AHR ligands such as indirubin. Each receptor has also been shown to differentially recruit LXXLL co-activator-motif proteins and to utilize different TAD subdomains in gene transactivation. Using hepatocytes isolated from C57BL6/J mice (Ahrb/b) and AHRTtr transgenic mice which express hAHR protein specifically in hepatocytes, we investigated whether the hAHR and mAHRb differentially regulate genes. Microarray and quantitative-PCR analysis of Ahrb/b and AHRTtr primary-mouse hepatocytes treated with 10 nM TCDD revealed that a number of established AHR target genes such as Cyp1a1 and Cyp1b1 are significantly induced by both receptors. Remarkably, of the 1752 genes induced by mAHRb and 1186 genes induced by hAHR, only 265 genes (<10%) were significantly activated by both receptors in response to TCDD. Conversely of the 1100 and 779 genes significantly repressed in mAHRb and hAHR hepatocytes respectively, only 462 (<25%) genes were significantly repressed by both receptors in response to TCDD treatment. Genes identified as differentially expressed are known to be involved in a number of biological pathways, including cell proliferation and inflammatory response which suggests that compared to the mAHRb, the hAHR may play contrasting roles in TCDD-induced toxicity and endogenous AHR-mediated gene regulation.
Differential gene regulation by the human and mouse aryl hydrocarbon receptor.
Specimen part
View SamplesIRE1a is a critical modulator of the unfolded protein response. Its RNAse activity generates the mature transcript for the XBP1 transcription factor and also degrades other ER associated mRNAs in a process termed Regulated IRE1a Dependent mRNA Decay or RIDD. To determine if IRE1a is critical in the response to oncogenic Ras we used ShRNA to knockdown Ire1a or Xbp1 in primary mouse epidermal keratinocytes transduced with a v-HRAS retrovirus.
ER stress and distinct outputs of the IRE1α RNase control proliferation and senescence in response to oncogenic Ras.
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View SamplesThe AhR is a ligand activated transcription factor that may be important in normal skin physiology. We compared gene expression profiles between AhR Wt and AhR KO primary mouse keratinocyte cultures. We identified 391 genes that were differentially expressed with a 1.5 fold cutoff and p<.05, and identified the AhR as an important regulator of genes involved in normal epidermal differentiation.
No associated publication
Specimen part
View SamplesImmune memory cells are poised to rapidly expand and elaborate effector functions upon reinfection. However, despite heightened readiness to respond, memory cells exist in a functionally quiescent state. The paradigm is that memory cells remain inactive due to lack of TCR stimuli. Here we report a unique role of Tregs in orchestrating memory quiescence by inhibiting effector and proliferation programs through CTLA-4. Loss of Tregs resulted in activation of genome-wide transcriptional programs characteristic of potent effectors, and both developing and established memory quickly reverted to a terminally differentiated (KLRG-1hi/IL-7Rlo/GzmBhi) phenotype, with compromised metabolic fitness, longevity, polyfunctionality and protective efficacy. CTLA-4, an inhibitory receptor overexpressed on Tregs, functionally replaced Tregs in trans to rescue Treg-less memory defects and restore homeostasis of secondary mediators as well. These studies present CD28-CTLA-4-CD80/CD86 axis as a novel target to potentially accelerate vaccine-induced immunity and improve T-cell memory quality in current cancer immunotherapies proposing transient Treg-depletion.
Quiescence of Memory CD8(+) T Cells Is Mediated by Regulatory T Cells through Inhibitory Receptor CTLA-4.
Specimen part
View SamplesHeterotrimeric G proteins mediate crucial and diverse signaling pathways in eukaryotes. To gain insights into the regulatory modes of the G protein and the co-regulatory modes of the G protein and the stress hormone abscisic acid (ABA), we generated and analyzed gene expression in G protein subunit single and double mutants of the model plant Arabidopsis thaliana.
Boolean modeling of transcriptome data reveals novel modes of heterotrimeric G-protein action.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Pluripotent stem cells reveal erythroid-specific activities of the GATA1 N-terminus.
Specimen part, Cell line, Time
View SamplesAnalysis of erythroid differentiation using Gata1 gene-disrupted G1E ER4 clone cells. Estradiol addition activates an ectopically expressed Gata-1-estrogen receptor fusion protein, triggering synchronous differentiation. 30 hour time course corresponds roughly to late burst-forming unit-erythroid stage (t=0 hrs) through orthochromatic erythroblast stage (t=30 hrs).
Erythroid GATA1 function revealed by genome-wide analysis of transcription factor occupancy, histone modifications, and mRNA expression.
Specimen part
View SamplesWe generated human induced pluripotent stem cells (iPSCs) from trisomy 21 (T21) and euploid patient tissues with and without GATA1 mutations causing exclusive expression of truncated GATA1, termed GATA1short (GATA1s). Transcriptome analysis comparing expression levels of genes in GATA1s vs. wtGATA1-expressing progenitors demonstrated that GATA1s impairs erythropoiesis and enhances megakaryopoiesis and myelopoiesis in both T21 and euploid contexts in the iPSC-model system.
Pluripotent stem cells reveal erythroid-specific activities of the GATA1 N-terminus.
Specimen part
View SamplesAlcoholic liver disease is a pathological condition caused by over-consumption of alcohol. Due to the high prevalence of morbidity and mortality associated with this disease, there remains a need to elucidate the molecular mechanisms underlying the etiology to develop new treatments. Since peroxisome proliferator-activated receptor-/ (PPAR/) modulates ethanol-induced hepatic effects, the present study examined alterations in gene expression that may contribute to this disease.
No associated publication
Sex, Specimen part
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