Translocation t(6;7) in AML-M4 cell line GDM-1 results in MNX1 activation through enhancer-hijacking [4C-seq]
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ABSTRACT: The leukemic cell line GDM-1 was established from a patient with acute myelomonoblastic leukemia [4]. GDM-1 cells carry a reciprocal translocation t(6;7)(q23;q36) juxtaposing the transcription factor (TF) gene motor neuron and pancreas homeobox 1 (MNX1, also designated HLXB9 or HB9) on chromosome 7 (chr7) to the locus of the transcriptional activator MYB on chr6. The translocation does not result in a fusion transcript but leads to aberrant activation of MNX1, suspected to be due to altered topologically associating domains, nuclear positioning or ectopic mechanisms. GDM-1 represents the only AML cell line overexpressing MNX1. Here we demonstrate that the interaction between the MNX1 promoter with a ‘hijacked’ enhancer from the MYB/AHI1 locus leads to ectopic activation of MNX1.
Project description:The leukemic cell line GDM-1 was established from a patient with acute myelomonoblastic leukemia [4]. GDM-1 cells carry a reciprocal translocation t(6;7)(q23;q36) juxtaposing the transcription factor (TF) gene motor neuron and pancreas homeobox 1 (MNX1, also designated HLXB9 or HB9) on chromosome 7 (chr7) to the locus of the transcriptional activator MYB on chr6. The translocation does not result in a fusion transcript but leads to aberrant activation of MNX1, suspected to be due to altered topologically associating domains, nuclear positioning or ectopic mechanisms. GDM-1 represents the only AML cell line overexpressing MNX1. Here we demonstrate that the interaction between the MNX1 promoter with a ‘hijacked’ enhancer from the MYB/AHI1 locus leads to ectopic activation of MNX1.
Project description:The leukemic cell line GDM-1 was established from a patient with acute myelomonoblastic leukemia [4]. GDM-1 cells carry a reciprocal translocation t(6;7)(q23;q36) juxtaposing the transcription factor (TF) gene motor neuron and pancreas homeobox 1 (MNX1, also designated HLXB9 or HB9) on chromosome 7 (chr7) to the locus of the transcriptional activator MYB on chr6. The translocation does not result in a fusion transcript but leads to aberrant activation of MNX1, suspected to be due to altered topologically associating domains, nuclear positioning or ectopic mechanisms. GDM-1 represents the only AML cell line overexpressing MNX1. Here we demonstrate that the interaction between the MNX1 promoter with a ‘hijacked’ enhancer from the MYB/AHI1 locus leads to ectopic activation of MNX1.
Project description:The leukemic cell line GDM-1 was established from a patient with acute myelomonoblastic leukemia [4]. GDM-1 cells carry a reciprocal translocation t(6;7)(q23;q36) juxtaposing the transcription factor (TF) gene motor neuron and pancreas homeobox 1 (MNX1, also designated HLXB9 or HB9) on chromosome 7 (chr7) to the locus of the transcriptional activator MYB on chr6. The translocation does not result in a fusion transcript but leads to aberrant activation of MNX1, suspected to be due to altered topologically associating domains, nuclear positioning or ectopic mechanisms. GDM-1 represents the only AML cell line overexpressing MNX1. Here we demonstrate that the interaction between the MNX1 promoter with a ‘hijacked’ enhancer from the MYB/AHI1 locus leads to ectopic activation of MNX1.
Project description:The leukemic cell line GDM-1 was established from a patient with acute myelomonoblastic leukemia [4]. GDM-1 cells carry a reciprocal translocation t(6;7)(q23;q36) juxtaposing the transcription factor (TF) gene motor neuron and pancreas homeobox 1 (MNX1, also designated HLXB9 or HB9) on chromosome 7 (chr7) to the locus of the transcriptional activator MYB on chr6. The translocation does not result in a fusion transcript but leads to aberrant activation of MNX1, suspected to be due to altered topologically associating domains, nuclear positioning or ectopic mechanisms. GDM-1 represents the only AML cell line overexpressing MNX1. Here we demonstrate that the interaction between the MNX1 promoter with a ‘hijacked’ enhancer from the MYB/AHI1 locus leads to ectopic activation of MNX1.
Project description:Acute myeloid leukemia (AML) in children with cytogenetic aberrations like translocation t(7;12)(q36;p13) is associated with inferior outcome. The translocation can lead to a fusion transcript MNX1::ETV6 but also to activation of MNX1 transcription. We generated an AML mouse model by transplantation of fetal liver cells with ectopic expression of MNX1. AML was highly penetrant in immunocompromised and less penetrant in immunocompetent mice. Transforming capacity was restricted to fetal liver cells and could not achieved with adult bone marrow cells, in concordance with the clinical finding that t(7;12)(q36;p13) is mostly restricted to infants. Ectopic expression of MNX1 led to increased H3K4methylation and reduced H3K27me3, possibly through its interaction with methyl transferases. MNX1 expression was accompanied with changes in genome wide chromatin accessibility , increased DNA damage, depletion in the LSK population and skewing toward the myeloid lineage. These effects, together with leukemia development, could be prevented by the S-adenosylmethionine analogue Sinefungin that acts as a SAM competitor and a pan methyltranferases inhibitor. Expression profiles of a human iPSC AML model with t(7;12) and of TARGET pediatric AML and TCGA patients support the rationale for targeting MNX1 and downstream pathways.
Project description:We have shown that increased β-cell proliferation in functioning pancreatic neuroendocrine tumors (insulinomas) correlated with expression of phosphorylated isoform of the transcription factor HLXB9 which is an embryonic beta-cell differentiation factor (HLXB9 is also known as HB9, MNR2, and MNX1). To investigate the target genes of phospho-HLXB9 we did ChIP-seq using anti-HB9-PO4. This would help us better understand how phospho-HLXB9 regulates its targets and affects β-cell proliferation in insulinoma cells.