Project description:Notch1-IC, Notch2-IC or EBNA2 have been induced in a conditionally immortalized human B cell line (EREB2-5) in order to identify similar and unique target genes in B cells. CAT was used as a control. Experiment Overall Design: RNA was isolated at different time points after induction of Notch1-IC, Notch2-IC or EBNA2 in EREB2-5 cells. Three independent experiments were performed (except Notch1-IC at 3day).
Project description:Notch1-IC, Notch2-IC or EBNA2 have been induced in a conditionally immortalized human B cell line (EREB2-5) in order to identify similar and unique target genes in B cells. CAT was used as a control. Keywords: time course
Project description:To determine role of Notch signaling in AML leukemia initiating cells we used a conditional mouse knock-in model of Notch1-IC to induce Notch1-IC expression in MLL-AF9 transformed LGMP. WT and Notch1-IC+ LGMP were analyzed to determined genes controlled by Notch signaling.
Project description:Notch signaling plays essential roles in maintenance of muscle stem cell pool. We found that Notch2, but not Notch1 and Notch3, is expressed in fully differentiated myofibers. To study the specific role of Notch2 in adult myofibers, we generated muscle-specific Notch2-knockout mice. Here, we showed that muscle-specific Notch2 deficiency prevented muscle atrophy induced by hindlimb unloading and diabetes millitus. RNA sequencing analysis revealed that the loss of Notch2 gene in myofibers inhibited gene responses to unloading and diabetes. Especially, several FoxO-target genes and atrogenes were upregulated in wildtype muscles but not in Notch2-deficient muscles by unloading and diabetes. Thus, our characterization of muscle-specific Notch2-knockout mice indicates that Notch2 acts as a regulatory factor of skeletal muscle plasticity and could be a therapeutic target of muscle atrophy.
Project description:To determine role of Notch signaling in AML leukemia initiating cells we used a conditional mouse knock-in model of Notch1-IC to induce Notch1-IC expression in MLL-AF9 transformed LGMP. WT and Notch1-IC+ LGMP were analyzed to determined genes controlled by Notch signaling. 12 weeks old wt lethaly irradiated mice were transplanted with 50000 cKit+ MLL-AF9-IRES-YFP infected cells from MLL-AF9 EF1 wt/wt ROSAwt/CreERT2 or MLL-AF9 EF1 wt/lsl-N1-IC ROSAwt/CreERT2 mice + 250000 support wt total bone marrow cells. 4 weeks after transplant mice were injected 2 times with tamoxifen (0.2mg/g body weight) every other day. Mice were sacrificed and analyzed 6 days after last injection. LGMP were flow purified for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Next generation sequencing was used to identify Notch mutations in a large collection of diverse solid tumors. NOTCH1 and NOTCH2 rearrangements leading to constitutive receptor activation were confined to triple negative breast cancers (TNBC, 6 of 66 tumors). TNBC cell lines with NOTCH1 rearrangements associated with high levels of activated NOTCH1 (N1-ICD) were sensitive to the gamma-secretase inhibitor (GSI) MRK-003, both alone and in combination with pacitaxel, in vitro and in vivo, whereas cell lines with NOTCH2 rearrangements were resistant to GSI. Immunohistochemical staining of N1-ICD in TNBC xenografts correlated with responsiveness, and expression levels of the direct Notch target gene HES4 correlated with outcome in TNBC patients. Activating NOTCH1 point mutations were also identified in other solid tumors, including adenoid cystic carcinoma (ACC). Notably, ACC primary tumor xenografts with activating NOTCH1 mutations and high N1-ICD levels were sensitive to GSI, whereas N1-ICD low tumors without NOTCH1 mutations were resistant. Gene expression profiling for Notch-sensitive cancer cell lines using RNA-seq, each sample with triplicates
Project description:Next generation sequencing was used to identify Notch mutations in a large collection of diverse solid tumors. NOTCH1 and NOTCH2 rearrangements leading to constitutive receptor activation were confined to triple negative breast cancers (TNBC, 6 of 66 tumors). TNBC cell lines with NOTCH1 rearrangements associated with high levels of activated NOTCH1 (N1-ICD) were sensitive to the gamma-secretase inhibitor (GSI) MRK-003, both alone and in combination with pacitaxel, in vitro and in vivo, whereas cell lines with NOTCH2 rearrangements were resistant to GSI. Immunohistochemical staining of N1-ICD in TNBC xenografts correlated with responsiveness, and expression levels of the direct Notch target gene HES4 correlated with outcome in TNBC patients. Activating NOTCH1 point mutations were also identified in other solid tumors, including adenoid cystic carcinoma (ACC). Notably, ACC primary tumor xenografts with activating NOTCH1 mutations and high N1-ICD levels were sensitive to GSI, whereas N1-ICD low tumors without NOTCH1 mutations were resistant.
Project description:Epstein-Barr virus (EBV) infection converts resting human B cells into permanently growing lymphoblastoid cell lines (LCLs). The viral Epstein-Barr virus nuclear antigen 2 (EBNA2) plays key role in this process. It preferentially binds to B cell enhancers and establishes a specific viral and cellular gene expression program in LCLs. The cellular DNA binding factor CBF1/CSL serves as a sequence specific chromatin anchor for EBNA2. The ubiquitous expression of this highly conserved protein raises the question whether additional cellular factors might determine EBNA2 chromatin binding selectively in B cells. Here we used CBF1 deficient B cells to identify cellular genes up or downregulated by EBNA2 as well as CBF1 independent EBNA2 chromatin binding sites. Both, CBF1 independent EBNA2 target genes and chromatin binding sites are less frequent than CBF1 dependent EBNA2 functions. CBF1 independent EBNA2 binding sites are highly enriched for EBF1 binding motifs. We show that EBNA2 binds to EBF1 in CBF1 proficient and deficient B cells and requires EBF1 to bind to CBF1 independent binding sites. Our results identify EBF1 as a co-factor of EBNA2 which conveys B cell specificity to EBNA2. In order to test, if EBNA2 can exert any functions in the absence of its DNA adaptor CBF1, a microarray based genome wide screen for EBNA2 target genes in DG75 B cells that are either proficient (wt) or deficient (ko) for CBF1 was performed. CBF1 deficient DG75 cells (SM224.9) cells had been generated by gene targeting using homologous recombination in the somatic B cell line DG75. Both cell lines, the CBF1 proficient DG75 parental cell line and the CBF1 deficient somatic knock-out cell line constitutively express an estrogen receptor (ER) hormone binding domain EBNA2 fusion protein (ER/EBNA2). ER/EBNA2 is retained in the cytoplasm of the cell but is rapidly activated and translocated to the nucleus in response to estrogen. For expression profiling, DG75, DG75 CBF1 ko (SM224.9), DG75 ER/EBNA2 CBF1 wt (SM295 D6) and DG75 ER/EBNA2 CBF1 ko (SM296 D3) cells were cultured in estrogen supplemented media for 24 h, total cellular RNAs were harvested and processed for the hybridization of gene arrays. The cellular system used for this study has been published: Maier S, Santak M, Mantik A, Grabusic K, Kremmer E, Hammerschmidt W, et al. A somatic knockout of CBF1 in a human B-cell line reveals that induction of CD21 and CCR7 by EBNA-2 is strictly CBF1 dependent and that downregulation of immunoglobulin M is partially CBF1 independent. Journal of Virology. 2005 Jul;79(14):8784-92. PubMed PMID: 15994772.
Project description:Notch receptors play crucial roles in the cell-fate decisions of tissue stem cells during development and regeneration. Notch1-3 receptors are expressed by satellite cells and their progeny. Here we found that Notch2, but not Notch1 or Notch3, was expressed in fully differentiated myofibers. Using transgenic mice that expressed a muscle-specific active form of Notch2 (N2ICD-mTG), we found that Notch2 activation remarkably reduced muscle mass and strength with a shift toward slow fibers. Transcriptome analyses revealed that growth differentiation factor 11 (GDF11) was highly up-regulated in muscles of N2ICD-mTG mice, and crucially, N2ICD-induced muscle atrophy was rescued by siRNA-mediated reduction of GDF11 expression. These data suggest that Notch2 functions in muscle to regulate muscle mass, in part, through induction of GDF11 expression, and reveal a novel aspect of Notch signaling in a terminally differentiated adult tissue.