Project description:We have developed a transgenic mouse model for Epstein-Barr virus-associated Burkitt's lymphoma. Transgenic mice that express LMP2A and MYC in B cells develop spontaneous lymph node tumors at different rates. Tumor onset occurs at approximately 40-60 days in LMP2A/λ-MYC mice and at 100-200 days in λ-MYC mice. This study compared total gene expression in the tumor cells from each genotype, as well as in B cells isolated from 3 week old mice prior to tumor onset. Comparison of total gene expression in tumor cells from LMP2A/λ-MYC and λ-MYC transgenic mice identified a short list of differentially expressed genes. Comparison of gene expression in B cells from the spleens of 3 week old mice, in contrast, identified a 10-fold increase in the number of differentially expressed genes.
Project description:We have developed a transgenic mouse model for Epstein-Barr virus-associated Burkitt's lymphoma. Transgenic mice that express LMP2A and MYC in B cells develop spontaneous lymph node tumors at different rates. Tumor onset occurs at approximately 40-60 days in LMP2A/λ-MYC mice and at 100-200 days in λ-MYC mice. This study compared total gene expression in the tumor cells from each genotype, as well as in B cells isolated from 3 week old mice prior to tumor onset. Comparison of total gene expression in tumor cells from LMP2A/λ-MYC and λ-MYC transgenic mice identified a short list of differentially expressed genes. Comparison of gene expression in B cells from the spleens of 3 week old mice, in contrast, identified a 10-fold increase in the number of differentially expressed genes. B cells from the spleens of 3 week old LMP2A/λ-MYC (n=5), λ-MYC (n=5), LMP2A (n=3), and WT (n=3) transgenic mice were purified using magnetic-activated cell sorting (MACS) beads purchased from Miltenyi for CD19 positive selection. Total RNA was isolated from these purified B cells, as well as from cervical lymph node tumor cells that developed in LMP2A/λ-MYC (n=7) and λ-MYC (n=5) transgenic mice using RNeasy RNA extraction kit from QIAGEN. Cervical lymph node tumor cells were >90% positive for the B cell marker B220, and were not further purified. Total gene expression was assessed in each sample, along with heart and brain reference samples using MouseRef-8 v2.0 Expression Bead Chips purchased from Illumina. GeneSpring analysis software was used to analyze the expression data and identify significantly differentially expressed genes (fold change >1.5-fold and false discovery rate< 0.05).
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:We created mice, which are deficient for Myc specifically in cardiac myocytes by crossing crossed Myc-floxed mice (Mycfl/fl) and MLC-2VCre/+ mice. Serial analysis of earlier stages of gestation revealed that Myc-deficient mice died prematurely at E13.5-14.5. Morphological analyses of E13.5 Myc-null embryos showed normal ventricular size and structure; however, decreased cardiac myocyte proliferation and increased apoptosis was observed. BrdU incorporation rates were also decreased significantly in Myc-null myocardium. Myc-null mice displayed a 3.67-fold increase in apoptotic cardiomyocytes by TUNEL assay. We examined global gene expression using oligonucleotide microarrays. Numerous genes involved in mitochondrial death pathways were dysregulated including Bnip3L and Birc2. Keywords: wildtype vs Myc-null
Project description:We created mice, which are deficient for Myc specifically in cardiac myocytes by crossing crossed Myc-floxed mice (Mycfl/fl) and MLC-2VCre/+ mice. Serial analysis of earlier stages of gestation revealed that Myc-deficient mice died prematurely at E13.5-14.5. Morphological analyses of E13.5 Myc-null embryos showed normal ventricular size and structure; however, decreased cardiac myocyte proliferation and increased apoptosis was observed. BrdU incorporation rates were also decreased significantly in Myc-null myocardium. Myc-null mice displayed a 3.67-fold increase in apoptotic cardiomyocytes by TUNEL assay. We examined global gene expression using oligonucleotide microarrays. Numerous genes involved in mitochondrial death pathways were dysregulated including Bnip3L and Birc2. Hearts were taken from wide type and Myc-null Mouse embryos at E13.5 under the dissecting scope. Cardiac myocyte RNA was isolated using TRIZOL®Reagent Total RNA (100 ng) was hybridized to the Sentrix® MouseRef-8 Expression BeadChip that contains probes for ~24,000 transcripts. GeneChips were scanned using the Hewlett-Packard GeneArray Scanner G2500A. The data were analyzed with Illumina Inc. BeadStudio version 1.5.0.34 and normalized by rank invariant method.
Project description:Epstein-Barr virus (EBV) infects human B cells and reprograms them to allow virus replication and persistence. One key viral factor in this process is latent membrane protein 2A (LMP2A), which has been described as a B cell receptor (BCR) mimic promoting malignant transformation. However, how LMP2A signaling contributes to tumorigenesis remains elusive. By systematically comparing LMP2A and BCR signaling using quantitative phosphoproteomics and transcriptome profiling, we identified molecular mechanisms through which LMP2A affects B cell biology. Consistent with previous literature, we found that LMP2A mimics a subset of BCR signaling events, including tyrosine-phosphorylation of the kinase SYK, the calcium initiation complex consisting of BLNK, BTK, PLC2, and its downstream transcription factor NFAT. However, the vast majority of LMP2A-induced signaling events markedly differed from those induced by BCR stimulation. These included differential phosphorylation of kinases, phosphatases, adaptor proteins, transcription factors such as NFB and TCF3, as well as widespread changes in the transcriptional output of LMP2A-expressing B cells. LMP2A affected apoptosis and cell cycle checkpoints by dysregulating the expression of apoptosis regulators such as Bcl-xL and the tumor suppressor retinoblastoma-associated protein (RB1). Accordingly, LMP2A cooperated with drivers of Burkitt lymphoma, overexpressed MYC and an oncogenic cyclin D3 mutant, by counteracting the pro-apoptotic effects of MYC and by further inhibiting RB1 function to promote cell growth. Our results indicate that LMP2A rewires rather than mimics BCR signaling, promoting a signaling output that predisposes EBV-infected B cells to hyperproliferation and eventual malignant transformation.
Project description:Our data shows that LMP2A promotes a more aggressive tumor phenotype. To evaluate the gene expression deregulated by LMP2A, RNA from the LMP2A cells and xenografted tumors were subjected to gene expression array.
Project description:Strict regulation of proliferation is vital for development, whereas unregulated cell proliferation is a fundamental characteristic of cancer. The polarity protein atypical protein kinase C lambda/iota (aPKC lambda) is associated with cell proliferation through unknown mechanisms. In endothelial cells, suppression of aPKC lambda impairs proliferation despite hyperactivated mitogenic signaling. Here we show that aPKC lambda phosphorylates the DNA binding domain of forkhead box O1 (FoxO1) transcription factor, a gatekeeper of endothelial growth. Although mitogenic signaling excludes FoxO1 from the nucleus, consequently increasing c-Myc abundance and proliferation, aPKC lambda controls c-Myc expression via FoxO1/miR-34c signaling without affecting its localization. We find this pathway is strongly activated in the malignant vascular sarcoma, angiosarcoma, and aPKC inhibition reduces c-Myc expression and proliferation of angiosarcoma cells. Moreover, FoxO1 phosphorylation at Ser218 and aPKC expression correlates with poor patient prognosis. Our findings may provide a new therapeutic strategy for treatment of malignant cancers, like angiosarcoma.