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:Recurrent somatic mutations in TET2 and in other genes that regulate the epigenetic state have been identified in patients with myeloid malignancies and in other cancers. However, the in vivo effects of Tet2 loss have not been delineated. We report here that Tet2 loss leads to increased stem-cell self-renewal and to progressive stem cell expansion. Consistent with human mutational data, Tet2 loss leads to myeloproliferation in vivo, notable for splenomegaly and monocytic proliferation. In addition, haploinsufficiency for Tet2 confers increased self-renewal and myeloproliferation, suggesting that the monoallelic TET2 mutations found in most TET2-mutant leukemia patients contribute to myeloid transformation. This work demonstrates that absent or reduced Tet2 function leads to enhanced stem cell function in vivo and to myeloid transformation. These studies show that a ubiquitin ligase-substrate pair can orchestrate the molecular program of HSC differentitiation Gene expression profiles from WT and Tet2-/- sorted LSK and myeloid progenitors (CMP and GMP) were compared using genome wide mRNA expression profiling by Affymetrix genechip arrays (Mouse 430 2.0) and key targets were validated by chromatin immunoprecipitation experiments.
Project description:Notch signaling is one of the central regulators of differentiation in a variety of organisms and tissue types. Within the hematopoietic system, Notch is essential for the emergence of definitive HSC during fetal life and controls adult HSC differentiation to the T-cell lineage. Notch activation is controlled by the gamma-secretase complex complex, composed of presenilin, nicastrin (Ncstn), anterior pharynx-1 (Aph1), and presenilin enhancer-2 To determine other role of Notch signaling in HSC we designed a conditional mouse model of Nicastrin deletion. WT and KO HSC were analysed to determined genes controlled by Notch signaling. Bone marrow lineage negative, cKit+, Sca1+ and lineage negative, cKit+, Sca1- CD34+ FcgammaRII/III+ cells were sorted from WT and Ncstn KO littermates for RNA extraction and hybridization on Affymetrix microarrays
Project description:Notch signaling is one of the central regulators of differentiation in a variety of organisms and tissue types. Within the hematopoietic system, Notch is essential for the emergence of definitive HSC during fetal life and controls adult HSC differentiation to the T-cell lineage. Notch activation is controlled by the gamma-secretase complex complex, composed of presenilin, nicastrin (Ncstn), anterior pharynx-1 (Aph1), and presenilin enhancer-2 To determine other role of Notch signaling in HSC we designed a conditional mouse model of Nicastrin deletion. WT and KO HSC were analysed to determined genes controlled by Notch signaling. Bone marrow lineage negative, cKit+, Sca1+ cells were sorted from WT and Ncstn KO littermates for RNA extraction and hybridization on Affymetrix microarrays
Project description:Notch signaling is one of the central regulators of differentiation in a variety of organisms and tissue types. Within the hematopoietic system, Notch is essential for the emergence of definitive HSC during fetal life and controls adult HSC differentiation to the T-cell lineage. Notch activation is controlled by the gamma-secretase complex complex, composed of presenilin, nicastrin (Ncstn), anterior pharynx-1 (Aph1), and presenilin enhancer-2 To determine other role of Notch signaling in HSC we designed a conditional mouse model of Notch activation. WT and N1-IC+ HSC were analysed to determined genes controlled by Notch signaling. Bone marrow lineage negative, cKit+, Sca1+ cells were sorted from WT and N1-IC+ littermates for RNA extraction and hybridization on Affymetrix microarrays
Project description:Notch signaling defines a conserved, fundamental pathway, responsible for determination in metazoan development and is widely recognized as an essential component of lineage specific differentiation and stem cell self-renewal in many tissues including the hematopoietic system. Until recently, the majority of studies in the hematopoietic system focused on Notch signaling in lymphocyte differentiation and knowledge of individual Notch receptor roles in early hematopoiesis has been limited due to a paucity of genetic tools available To fate-map Notch receptor expression and pathway activity in the hematopoietic system we used tamoxifen-inducible CreER knock-in mice for individual Notch receptors in combination to a novel Notch reporter strain (Hes1GFP) and a conditional gain of function allele of Notch2 receptor (Rosa-lsl-ICN2). Bone marrow lineage negative, cKit+, Sca1- cells were sorted from Rosa-lsl-ICN2 Mx1-cre+ mice or Mx1-cre+ littermates for RNA extraction and hybridization on Affymetrix microarrays
Project description:Hematopoietic stem cells and progenitors from controls and Med12Flox; mxCre mice treated with pI:pC 4 days afters injection were sorted and Micrroarray Affymetrix mouse 430.2 platform. Results provide insight into the gene signatures regulated by Med12 that are essential for the homeostasis of the hematopoietic system. Microarrays we used to characterize the gene expression programs regulated by Med12 and identified down-regulated signatures
Project description:Notch signaling defines a conserved, fundamental pathway, responsible for determination in metazoan development and is widely recognized as an essential component of lineage specific differentiation and stem cell self-renewal in many tissues including the hematopoietic system. Until recently, the majority of studies in the hematopoietic system focused on Notch signaling in lymphocyte differentiation and knowledge of individual Notch receptor roles in early hematopoiesis has been limited due to a paucity of genetic tools available To fate-map Notch receptor expression and pathway activity in the hematopoietic system we used tamoxifen-inducible CreER knock-in mice for individual Notch receptors in combination to a novel Notch reporter strain (Hes1GFP) and a conditional gain of function allele of Notch2 receptor (Rosa-lsl-ICN2). E13.5 Foetal Liver lineage negative, cKit+, Sca1+ cells were sorted from Hes-GFP mice for RNA extraction and hybridization on Affymetrix microarrays