Project description:Total RNA was isolated from mouse Asxl2-/- and WT LK cells following standard protocol with TRIZol reagent (Life Technologies) followed by RNA library preparation with the Illumina TruSeq strand-specific mRNA sample preparation system. All RNA-seq libraries were sequenced with a read length of single-end 75bp using the Illumina NextSeq 500, and final of over 45 million reads per sample.
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: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
Project description:LK cells of each mouse genotype were fixed with 1% formaldehyde for 15 min and quenched with 0.125 M glycine. Chromatin was isolated by the addition of lysis buffer, followed by shearing with Bioruptor Pico with water cooler (Diagenode, Seraing, Belgium). The DNA was sheared to an average length of 300-500 bp. Genomic DNA regions of interest were isolated using antibodies against H3K27ac (Diagenode, C15410196), H3K4me1 (C15410194), and H3K4me2 (Abcam, ab32356). Complexes were washed, eluted from the beads with SDS buffer, and subjected to RNase and proteinase K treatment. Crosslinks were reversed by incubation overnight at 65°C, and ChIP DNA was purified by phenol-chloroform extraction and ethanol precipitation. After the measurement of DNA concentration with Qubit3.0, the libraries were prepared and sequenced on an Illumina NextSeq 500.
Project description:Chromosomal translocation t(8;21) (q22;q22) leading to generation of oncogenic RUNX1-RUNX1T1 (AML1-ETO) fusion is a cytogenetic abnormality observed in about 10% of acute myelogenous leukemia (AML). To uncover somatic mutations that cooperate with t(8;21)-driven leukemia, we performed targeted and whole exome sequencing of newly-diagnosed and relapsed AML samples. We identified high frequency of truncating alterations in ASXL2 along with recurrent mutations of KIT, TET2, MGA, FLT3, and DHX15 in this subtype of AML. To investigate in-depth the role of ASXL2 in normal and malignant hematopoiesis, we utilized a mouse model of ASXL2 deficiency. Loss of ASXL2 caused progressive hematopoietic defects characterized by myeloid cell expansion, splenomegaly, extramedullary hematopoiesis and poor reconstitution ability in transplantation models. A parallel analysis of young and >1-year old Asxl2-deficient mice revealed age-dependent changes in the hematopoietic compartment leading to perturbations affecting not only myeloid and erythroid differentiation but also maturation of lymphoid cells. Our studies also suggest that expression of truncated ASXL2 protein confers proliferative advantage to mouse myeloid progenitors. Overall, these findings establish a critical role of ASXL2 in maintaining steady state hematopoiesis and provide insights into how its loss/mutation primes leukemic growth of myeloid cells.
Project description:Chromosomal translocation t(8;21) (q22;q22) leading to generation of oncogenic RUNX1-RUNX1T1 (AML1-ETO) fusion is a cytogenetic abnormality observed in about 10% of acute myelogenous leukemia (AML). To uncover somatic mutations that cooperate with t(8;21)-driven leukemia, we performed targeted and whole exome sequencing of newly-diagnosed and relapsed AML samples. We identified high frequency of truncating alterations in ASXL2 along with recurrent mutations of KIT, TET2, MGA, FLT3, and DHX15 in this subtype of AML. To investigate in-depth the role of ASXL2 in normal and malignant hematopoiesis, we utilized a mouse model of ASXL2 deficiency. Loss of ASXL2 caused progressive hematopoietic defects characterized by myeloid cell expansion, splenomegaly, extramedullary hematopoiesis and poor reconstitution ability in transplantation models. A parallel analysis of young and >1-year old Asxl2-deficient mice revealed age-dependent changes in the hematopoietic compartment leading to perturbations affecting not only myeloid and erythroid differentiation but also maturation of lymphoid cells. Our studies also suggest that expression of truncated ASXL2 protein confers proliferative advantage to mouse myeloid progenitors. Overall, these findings establish a critical role of ASXL2 in maintaining steady state hematopoiesis and provide insights into how its loss/mutation primes leukemic growth of myeloid cells.