Project description:CHD7 interacts with CBFb-SMMHC through RUNX1 and modulates their gene expression regulation and is important for CBFB-MYH11 leukemogenesis in the mouse model.
Project description:Results showed that Chd7 deficiency delay Cbfb-MYH11 induced leukemia, to explore the mechanism, We also performed microarray analysis on c-Kit+ leukemic cells to determine gene expression differences between Mx1-Cre, Cbfb+/56M and Chd7f/f, Mx1-Cre, Cbfb+/56M leukemic cells.
Project description:It is known that CBFB-MYH11, the fusion gene generated by inversion of chromosome 16 in human acute myeloid leukemia, is causative for oncogenic transformation. However, the mechanism by which CBFB-MYH11 initiates leukemogenesis is not clear. Previously published reports showed that CBFB-MYH11 dominantly inhibits RUNX1 and CBFB, and such inhibition has been suggested as the mechanism for leukemogenesis. However, knockin mice expressing Cbfb-MYH11 (Cbfb+/MYH11) showed defects in primitive hematopoiesis not seen in Cbfb null (Cbfb-/-) embryos indicating that Cbfb-MYH11 has repression independent activities as well. To identify gene expression changes associated with this novel activity, we compared the gene expression profile in the blood cells of Cbfb+/MYH11 and Cbfb-/- embryonic day 12.5 (E12.5) embryos with that of their wildtype littermates. Cbfb-MYH11 chimeras were mated to C57/Bl6 females to generate Cbfb+/MYH11 (Cbfb+/MYH11) and Cbfb+/+ (WT) embryos. Cbfb+/- x Cbfb+/- matings were used to generate Cbfb+/+ (Cbfb+/+) and Cbfb-/- (Cbfb-/-) embryos. Blood from 8-10 E12.5 embryos of the same genotype was pooled, and RNA was isolated, labeled, and hybridized to Affymetrix Genechip mouse microarray (430 2.0) chips. 4 chips were used for both the Cbfb+/MYH11 and littermate control samples. 3 chips were used for the Cbfb-/- samples and littermate control samples.
Project description:It is known that CBFB-MYH11, the fusion gene generated by inversion of chromosome 16 in human acute myeloid leukemia, is causative for oncogenic transformation. However, the mechanism by which CBFB-MYH11 initiates leukemogenesis is not clear. Previously published reports showed that CBFB-MYH11 dominantly inhibits RUNX1 and CBFB, and such inhibition has been suggested as the mechanism for leukemogenesis. However, knockin mice expressing Cbfb-MYH11 (Cbfb+/MYH11) showed defects in primitive hematopoiesis not seen in Cbfb null (Cbfb-/-) embryos indicating that Cbfb-MYH11 has repression independent activities as well. To identify gene expression changes associated with this novel activity, we compared the gene expression profile in the blood cells of Cbfb+/MYH11 and Cbfb-/- embryonic day 12.5 (E12.5) embryos with that of their wildtype littermates.
Project description:Inversion of chromosome 16 is a consistent finding in patients with acute myeloid leukemia subtype M4 with eosinophilia (AML M4Eo), which generates a CBFB-MYH11 fusion gene. It is generally considered that CBFβ-SMMHC, the fusion protein encoded by CBFB-MYH11, is a dominant negative repressor of RUNX1. However, recent findings challenge the RUNX1-repression model for CBFβ-SMMHC mediated leukemogenesis. To definitively address the role of Runx1 in CBFB-MYH11 induced leukemia, we crossed conditional Runx1 knockout mice (Runx1f/f) with conditional Cbfb-MYH11 knockin mice (Cbfb+/56M). Upon Mx1-Cre activation in hematopoietic cells induced by poly (I:C) injection, all Mx1-CreCbfb+/56M mice developed leukemia in 5 months while no leukemia developed in Runx1f/fMx1-CreCbfb+/56M mice, and this effect was cell autonomous. Importantly, the abnormal myeloid progenitors (AMPs), a leukemia initiating cell population induced by Cbfb-MYH11 in the bone marrow, decreased and disappeared in Runx1f/fMx1-CreCbfb+/56M mice. RNA-seq analysis of AMP cells showed that genes associated with proliferation, differentiation blockage and leukemia initiation, were differentially expressed between Mx1-CreCbfb+/56M and Runx1f/fMx1-CreCbfb+/56M mice. In addition, with chromatin immunocleavage sequencing (ChIC-seq) assay, we observed a significant enrichment of RUNX1/CBFβ-SMMHC target genes in Runx1f/fMx1-CreCbfb+/56M cells, especially among down-regulated genes, suggesting that RUNX1 and CBFβ-SMMHC mainly function together as activators of gene expression through direct target gene binding. These data indicate that Runx1 is indispensable for Cbfb-MYH11 induced leukemogenesis by working together with CBFβ-SMMHC to regulate critical genes associated with the generation of a functional AMP population.
Project description:The recurrent chromosome 16 inversion in acute myeloid leukemia generates a fusion gene between CBFB and MYH11, which in turn encodes a chimeric protein CBFβ-SMMHC (core binding factor β-smooth muscle myosin heavy chain). We previously demonstrated that CBFβ-SMMHC needs its C terminal domains for leukemogenesis. In this study, we generated a new Cbfb-MYH11 knock-in mouse model to dissect the role of the multimerization domain at the C terminus of CBFβ-SMMHC. Specifically, we mutated six amino acids in the helices D and E (mDE) of the assembly competent domain, which is important for SMMHC multimerization. We found that the embryos with the mDE mutation (Cbfb+/mDE) did not develop hematopoietic defects seen in embryos with full-length CBFβ-SMMHC (Cbfb+/MYH11). More importantly leukemia development was abolished in the adult Cbfb+/mDE mice even after mutagenesis treatment. In addition, gene expression profile of the hematopoietic cells from the Cbfb+/mDE mice was more similar to that of Cbfb+/+ mice than the Cbfb+/MYH11 mice. Our data suggest that the C terminal multimerization domain is required for the defects in primitive and definitive hematopoiesis caused by CBFβ-SMMHC, and it is also essential for leukemogenesis caused by CBFβ-SMMHC.
Project description:We searched for genes which are mutated in a manner that is linked with gene mutations involved in DNA de/methylation in AML. We found that recurrent CBFB-MYH11 fusions, which result in the expression of fusion protein comprising core-binding factor β (CBFB) and myosin heavy chain 11 (MYH11), occur mutually exclusively with DNMT3A mutations. The CBFB-MYH11 fusion tumors show DNA hypomethylation patterns similar to cancers with loss-of-function mutation of DNMT3A. Expression of CBFB-MYH11 fusion protein or inhibition of DNMT3A similarly impairs the methylation and expression of target genes of Runt related transcription factor 1 (RUNX1), a functional partner of CBFB. We demonstrate that RUNX1 directly interacts with DNMT3A and that CBFB-MYH11 fusion protein sequesters RUNX1 in the cytoplasm, thereby preventing RUNX1 from interacting with and recruiting DNMT3A to its target genes. Our results identify a novel regulation of DNA methylation and provide a molecular basis how CBFB-MYH11 fusion contributes to leukemogenesis.
Project description:To clarify the role of Gata2 in the development of Cbfb-MYH11 induced leukemia, we generated conditional Cbfb-MYH11 knockin mice with Gata2 heterozygous knockout. Leukemic cells with Gata2 heterozygous knockout gained higher number of genetic mutations and showed more aggressive phenotype in both primary and transplanted recipient mice. We compared gene expression profilings between Gata2+/+ and Gata2+/f leukemic cells with Cbfb-MYH11.
Project description:AML patient GMPs or CMPs were FACS sorted as described in Supplementary Information (Reckzeh, K et al. 2020) TET2 deficiency cooperates with CBFB-MYH11 to induce acute myeloid leukemia and represents an early leukemogenic event. Reckzeh, K et al