Role of H3K79 methylation states in HOX gene expression and leukemogenesis
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ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Scott Armstrong
PROVIDER: E-GEOD-54500 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:We wanted to investigate the effects of Dot1l deletion on gene expression in LSKs and GMPs of C57/BL6 mice Aberrant Hox gene activation is a recurrent feature in several different types of human leukemia, including leukemias with rearrangements of the mixed lineage leukemia (MLL) gene. In this study, we demonstrate that Hox gene expression is controlled by higher degree H3K79 methylation in acute myeloid leukemia (AML). We show that the deposition of progressive H3K79 methylation states at the genomic loci of critical Hox genes is dependent on the interaction of the H3K79 methyltransferase Dot1l with Af10, a protein that is found in the Dot1l complex isolated from diverse cell types. Furthermore, abrogation of the Dot1l-Af10 interaction reverses aberrant epigenetic profiles found in the leukemia epigenome and impairs the transforming ability of mechanistically distinct AML oncogenes. Lineage negative Sca-1 positive Kit positive (LSK) cells and granulocyte macrophage progenitors (GMPs) were sorted from Dot1 wt/wt x Mx-Cre mice or Dot1l fl/fl x Mx-Cre mice were injected with PIPC. PIPC injection induced biallelic deletion of the Dot1l allele in the Dot1l fl/fl mice but not the Dot1l wt/wt mice. The Dot1l wt/wt LSKs and GMPs were compared to the Dot1l -/- counterparts by RNA extraction and Microarrays.
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Project description:Aberrant Hox gene activation is a recurrent feature in several different types of human leukemia, including leukemias with rearrangements of the mixed lineage leukemia (MLL) gene. In this study, we demonstrate that Hox gene expression is controlled by higher degree H3K79 methylation in acute myeloid leukemia (AML). We show that the deposition of progressive H3K79 methylation states at the genomic loci of critical Hox genes is dependent on the interaction of the H3K79 methyltransferase Dot1l with Af10, a protein that is found in the Dot1l complex isolated from diverse cell types. Furthermore, abrogation of the Dot1l-Af10 interaction reverses aberrant epigenetic profiles found in the leukemia epigenome and impairs the transforming ability of mechanistically distinct AML oncogenes. Primary MLL-AF9 leukemias in the AF10 floxed background (homozygous) were transduced with MSCV-IRES-tdTomato (MIT) or the Cre recombinase expressing MIT vector, cells were sorted and injected into secondary recipient mice to generate Af10 floxed (MIT) or deleted (CRE) leukemias. BM cells fresly harvested from these leukemias were sorted for tdTomato expression and used for microarrays. BM cells from Hoxa9-Meis1 transduced primary leukemias were used for comparison.
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