Project description:Identification of the genome-wide binding sites of Hoxa9 and C/EBPα in a murine myeloblastic cell line transformed by Hoxa9/Meis1. Over 50% of Hoxa9 binding sites are co-bound by C/EBPα, providing mechanistic insight into the requirement of C/EBPα for Hoxa9-mediated leukemogenesis. Additionally, genome-wide occupancy of H3K4 monomethylation and H3K27 trimethylation provide additional information on the functionality of Hoxa9/C/EBPα cobound loci. Examination of two transcription factor binding sites and two histone modifications in a transformed cell line.
Project description:Identification of the genome-wide binding sites of Hoxa9 and C/EBPα in a murine myeloblastic cell line transformed by Hoxa9/Meis1. Over 50% of Hoxa9 binding sites are co-bound by C/EBPα, providing mechanistic insight into the requirement of C/EBPα for Hoxa9-mediated leukemogenesis. Additionally, genome-wide occupancy of H3K4 monomethylation and H3K27 trimethylation provide additional information on the functionality of Hoxa9/C/EBPα cobound loci.
Project description:The transcription factor Meis1 drives myeloid leukemogenesis in the context of Hox gene overexpression but is currently considered undruggable. We therefore investigated whether myeloid progenitor cells transformed by Hoxa9 and Meis1 become addicted to targetable signaling pathways. A comprehensive (phospho)proteomic analysis revealed that Meis1 increased Syk protein expression and activity. Syk upregulation occurs through a Meis1-dependent feed-forward loop. By dissecting this loop, we show that Syk is a direct target of miR-146a, whose expression is indirectly regulated by Meis1 through the transcription factor PU.1. In the context of Hoxa9 overexpression, Syk induces Meis1, recapitulating several leukemogenic features of Hoxa9/Meis1-driven leukemia. Finally, we show that Syk inhibition disrupts the identified regulatory loop, prolonging survival of mice with Hoxa9/Meis1-driven leukemia.
Project description:RNAseq characterization of gene expression changes 72 hours after genomic excision of Cebpa in murine hematopoietic progenitors from Cebpaf/f;CreER mice transformed by Hoxa9/Meis1. In the presence of tamoxifen (4OHT), Cre-ER localizes to the nucleus of cells allowing for excision of Cebpa and loss of C/EBPα protein levels. Loss of C/EBPα leads to a decrease in cellular proliferation. Examination of gene expression by RNAseq in two conditions in biological replicates.
Project description:RNAseq characterization of gene expression changes 72 hours after genomic excision of Cebpa in murine hematopoietic progenitors from Cebpaf/f;CreER mice transformed by Hoxa9/Meis1. In the presence of tamoxifen (4OHT), Cre-ER localizes to the nucleus of cells allowing for excision of Cebpa and loss of C/EBPα protein levels. Loss of C/EBPα leads to a decrease in cellular proliferation.
Project description:In this study, we use a conditional mouse model for Cebpa to investigate the significance of C/EBPα in HSCs. The frequency of HSCs is unaltered following deletion of C/EBPα, however, upon serial transplantations of either full BM or purified HSCs, the stem cells and stem cell activity is lost. This is not due to increased proliferation, but rather caused by a shift from quiescence to apoptosis with a resultant exhaustion of the stem cell pool. We identify direct C/EBPα target genes by combining genome-wide C/EBPα ChIP-seq analysis in stem and progenitor cells with gene expression data from HSC with and without C/EBPα. Furthermore, we explore the impact of C/EBPα on active and repressive histone modifications by doing functional genome-wide ChIP-seq analysis of H3K4Me3 and H3K27Me3 in stem and progenitor cells with and without C/EBPα. We have sorted HSCs from 3 Cebpaflox/flox and 4 Cebpaflox/flox;Mx1Cre mice 18 days after pIC injection.
Project description:Meis1 is found cooperatively activated with Hoxa7/a9 in AML, and it indeed promotes leukemogenic activities of Hoxa9. It is important to identify downstream target genes of Meis1 to understand its cooperative activity with Hoxa9 in leukemogenesis. We used microarrays to detail the global programme of gene expression upon Meis1 knockout. Murine primary bone marrow cells of the Rosa26-Cre-ERT2 knock-in mouse were transformed by retroviral transduction of Hoxa9 and floxed Meis1. The immortalized bone marrow cells were treated with 2 μM of 4-hydroxytamoxifen to delete Meis1 cDNA. Gene expression profiles were compared between the original Hoxa9/Meis1-expressing cells and Meis1 deleted (Hoxa9 only) cells.
Project description:We report Illumina next generation RNA sequencing (RNAseq) of NUP98-HOXA9 in vitro transformed murine LSKs upon genetic deletion of Mll1. These gene expression data illustrate that Mll1 regulates Hoxa, Hoxb and Meis1 expression in NUP98-HOXA9 transformed murine BM cells.
Project description:To investigate whether co-expression of PBX3/MEIS1 can mimic that of MLL-AF9, HOXA9/MEIS1 or HOXA9/PBX3 in inducing leukemogenesis, we conducted in vivo mouse bone marrow transplantation (BMT) assays. Briefly, normal mouse bone marrow (BM) progenitor (i.e., lineage negative; Lin-) cells collected from B6.SJL (CD45.1) donor mice (CD45.1) were retrovirally co-transduced with MSCVneo-MLL-AF9+MSCV-PIG (MLL-AF9), MSCVneo-HOXA9+MSCV-PIG (HOXA9), MSCVneo-HOXA9+MSCV-PIG-MEIS1 (HOXA9+MEIS1), MSCVneo-HOXA9+MSCV-PIG-PBX3 (HOXA9+PBX3), MSCV-PIG-PBX3+MSCVneo-MEIS1 (PBX3+MEIS1), MSCVneo+MSCV-PIG-PBX3 (PBX3) , MSCVneo+MSCV-PIG-MEIS1 (MEIS1), or MSCVneo+MSCV-PIG (normal control; NC). Retrovirally transduced cells then were cultured with cytokines as well as puromycin and G418. Seven days later, the donor cells were transplanted into lethally irradiated (960 rads) 8- to 10-week-old C57BL/6 (CD45.2) recipient mice. The transplanted mice were watched for leukemogenesis. Then, gene expression profiling was conducted with bone marrow samples collected from leukemia groups and control group.