Activation-induced cytidine deaminase (AID) is essential for the generation of antibody memory but also targets oncogenes among others. We investigated the transcriptional regulation of the AID gene, Aicda, in the class switchinducible CH12F3-2 cells, and found that the Aicda regulation involves derepression by several layers of positive regulatory elements in addition to the 5 promoter region. The 5 upstream region contains functional motifs for the response to signaling by cytokines, CD40-ligand, or stimuli that activate NF-B. The first intron contains functional binding elements for the ubiquitous silencers c-Myb and E2f and for B cellspecific activator Pax5 and E-box-binding proteins.
B cell-specific and stimulation-responsive enhancers derepress Aicda by overcoming the effects of silencers.
Specimen part
View SamplesMost human B cell lymphomas (B-NHL) are derived from germinal centers (GCs), the structure where B-cells undergo class switch recombination (CSR) and somatic hypermutation (SHM) and are selected for high-affinity antibody production. The pathogenesis of B-NHL is associated with distinct genetic lesions, including chromosomal translocations and aberrant somatic hypermutation, which appear to arise from mistakes occurring during CSR and SHM. To ascertain the role of CSR and SHM in lymphomagenesis, we crossed three oncogene-driven (MYC, BCL6, MYC/BCL6) mouse models of B cell lymphoma with mice lacking activation-induced cytidine deaminase (AID), the enzyme required for both processes.
AID is required for germinal center-derived lymphomagenesis.
Specimen part
View SamplesBACKGROUND: Peroxisome proliferator-activated receptor g (PPAR g) is a nuclear receptor whose activation has been shown to modulate macrophage and epithelial cell-mediated inflammation. The objective of this study was to use a systems approach for investigating the mechanism by which the deletion of PPAR g in T cells modulates the severity of dextran-sodium sulfate (DSS)-induced colitis, immune cell distribution and global gene expression.
The role of T cell PPAR gamma in mice with experimental inflammatory bowel disease.
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View SamplesPPARg and C/EBPa cooperate to control preadipocyte differentiation (adipogenesis). However, the factors that regulate PPARg and C/EBPa expression during adipogenesis remain largely unclear. Here we show PTIP, a protein that associates with histone H3K4 methyltransferases, regulates PPARg and C/EBPa expression in mouse embryonic fibroblasts (MEFs) and during preadipocyte differentiation. PTIP deletion in MEFs leads to marked decreases of PPARg expression and PPARg-stimulated C/EBP expression. Further, PTIP is essential for induction of PPARg and C/EBPa expression during preadipocyte differentiation. Deletion of PTIP impairs the enrichment of H3K4 trimethylation and RNA polymerase II on PPARg and C/EBPa promoters. Accordingly, PTIP-/- MEFs and preadipocytes all show striking defects in adipogenesis. Furthermore, rescue of the adipogenesis defect in PTIP-/- MEFs requires co-expression of PPARg and C/EBPa. Finally, deletion of PTIP in brown adipose tissue significantly reduces tissue weight in mice. Thus, by regulating PPARg and C/EBPa expression, PTIP plays a critical role in adipogenesis.
Histone methylation regulator PTIP is required for PPARgamma and C/EBPalpha expression and adipogenesis.
Cell line
View SamplesBACKGROUND: Peroxisome proliferator-activated receptor g (PPAR g) is a nuclear receptor whose activation has been shown to modulate macrophage and epithelial cell-mediated inflammation. The objective of this study was to use a systems approach for investigating the mechanism by which the deletion of PPAR g in epithelial cells modulates the severity of dextran-sodium sulfate (DSS)-induced colitis, immune cell distribution and global gene expression.
Immunoregulatory actions of epithelial cell PPAR gamma at the colonic mucosa of mice with experimental inflammatory bowel disease.
Specimen part
View SamplesBackground: It has been shown previously that administration of Francisella tularensis (Ft) LVS lipopolysaccharide (LPS) protects mice against subsequent challenge with Ft LVS and blunts the pro-inflammatory cytokine response.
Modulation of hepatic PPAR expression during Ft LVS LPS-induced protection from Francisella tularensis LVS infection.
Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
An integrated systems biology approach identifies positive cofactor 4 as a factor that increases reprogramming efficiency.
Sex, Specimen part
View SamplesMultipotent spermatogonial stem cells (mSSCs) derived from SSCs are a potential new source of individualized pluripotent cells in regenerate medicine such as ESCs. We hypothesized that the culture-induced reprogramming of SSCs was mediated by a mechanism different from that of iPS, and was due to up-regulation of specific pluripotency-related genes during cultivation. Through a comparative analysis of expression profile data, we try to find cell reprogramming candidate factors from mouse spermatogonial stem cells. We used microarrays to analyze the gene expression profiles of culture-induced reprogramming converting unipotent spermatogonial stem cells to pluripotent spermatogonial stem cells.
An integrated systems biology approach identifies positive cofactor 4 as a factor that increases reprogramming efficiency.
Sex, Specimen part
View SamplesVinylidene Chloride has been widely used in the production of plastics and flame retardants. Exposure of B6C3F1 to VDC in the 2-year National Toxicology Program carcinogenicity bioassay resulted in a dose-dependent increase in renal cell hyperplasias, adenomas, and carcinomas (RCCs). Global gene expression analysis showed overrepresentation of pathways associated with chronic xenobiotic and oxidative stress in RCCs from VDC-exposed B6C3F1 mice, as well as cMyc overexpression and dysregulation of Tp53 cell cycle checkpoint and DNA damage repair pathways. Trend analysis comparing RCC, VDC-exposed kidney, and vehicle control kidney showed a conservation of pathway dysregulation in terms of overrepresentation of xenobiotic and oxidative stress, and DNA damage and cell cycle checkpoint pathways in both VDC-exposed kidney and RCC, suggesting that these mechanisms play a role in the development of RCC in VDC-exposed mice.
Renal Cell Carcinomas in Vinylidene Chloride-exposed Male B6C3F1 Mice Are Characterized by Oxidative Stress and TP53 Pathway Dysregulation.
Specimen part
View SamplesHepatocellular carcinoma (HCC) is an important cause of morbidity and mortality worldwide. Although the risk factors of human HCC are well known, the molecular characterization of this disease is complex, and treatment options in general remain poor. The use of rodent models to study human cancer has been extensively pursued both through genetically engineered rodents and rodent models used in carcinogenicity and toxicology studies. In particular, the B6C3F1 mouse used in the National Toxicology Program (NTP) 2-year bioassay has been used to evaluate the carcinogenic effects of environmental and occupational chemicals, and other compounds. The high incidence of spontaneous HCC in the B6C3F1 mouse has challenged its use as a model for chemically induced HCC in terms of relevance to the human disease. Using global gene expression profiling, we identify the dysregulation of several mediators similarly altered in human HCC, including re-expression of fetal oncogenes, upregulation of protooncogenes, downregulation of tumor suppressor genes, and abnormal expression of cell cycle mediators, growth factors, apoptosis regulators, and angiogenesis and extracellular matrix remodeling factors. Although important differences in etiology and pathogenesis remain between human and mouse HCC, there are important similarities in global gene expression and the types of signaling networks dysregulated in mouse and human HCC. These data provide further relevance for the use of this model in hazard identification of compounds with potential human carcinogenicity risk, and may help in better understanding mechanisms of tumorigenesis due to chemical exposure in the NTP 2-year carcinogenicity bioassay.
Global gene profiling of spontaneous hepatocellular carcinoma in B6C3F1 mice: similarities in the molecular landscape with human liver cancer.
Specimen part
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