RNAseq of murine primary bone marrow cells transformed by an inducible Hoxa9-ER: time-course
ABSTRACT: Relative overexpression of HOXA9 is a key feature of aggressive AML (acute myeloid leukemia). Hoxa9 responsive genes were identified by nascent RNA sequencing (4-thio-uridine labeled RNA - sequencing) in samples of primary hematopoietic precursor cells from mice transformed by an tamoxifen inducible version of Hoxa9 (Hoxa9-ER). Samples were generated in the presence of active Hoxa9 (0h) and in a time series after Hoxa9 was inactivated at 8h, 16h, 24h, 48h, and 72h.
Project description:Relative overexpression of HOXA9 is a key feature of aggressive AML (acute myeloid leukemia). Here we determined genome wide binding sites of Hoxa9 in primary murine cells transformed by Hoxa9 and in a human AML cell line. In addition global H3K4 monomethylation and H3K27acetylation levels were determined in cells transformed by an inducible Hoxa9-ER construct in Hoxa9-active conditions and 72h after Hoxa9 was inactivated.
Project description:Characterization of gene expression changes 72 hours after withdrawal of tamoxifen in murine hematopoietic progenitors transformed by Hoxa9-ER/Meis1 using RNAseq. In the presence of tamoxifen (4OHT), Hoxa9-ER localizes to the nucleus of cells allowing for transformation, while withdrawal of 4OHT (culture in EtOH) leads to loss of nuclear Hoxa9-ER. Loss of Hoxa9-ER leads to a decrease in cellular proliferation and differentiation along the myeloid lineage. Examination of gene expression by RNAseq in two conditions in biological replicates.
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:Drosophila melanogaster Schneider cells (S2) were transfected with a 2'-O-methyl inhibitor antisense to miR-277 or an unrelated control sequence. Three days after inhibition of the miRNA, the cellular RNA was pulse-labeled with 4-thio-Uridine for 1 hour, then tthe cells were lysed and RNA was extracted with Trizol. Following extraction, the RNA was further fractionated by in vitro biotinylation of incorporated 4-thio-uridine, yielding altogether three RNA fractions for each sample: total, newly transcribed (=labeled) and > 1h old (=unlabeled).
Project description:Human Intestinal Organoids (HIOs) generated from embryonic and/or induced pluripotent stem cell lines offer an avenue to study both developmental and human specific disease states. Recently, progress has been made in scaling and maturing these inherently immature tissues through transplanting them in vivo. However, these resultant grafts best approximate fetal intestinal tissue thus limiting their utility. To induce growth and maturation of HIOs we used a nitinol spring device to mechanically induce enterogenesis of HIO in vivo. HIOs are cultured prior to implantation within the mesentery of immunodeficient mice. They are allowed to grow, vascularize, and mature before a second procedure is performed wherein a compressed nitinol spring is implanted within the lumen of the transplanted HIO (tHIO). Next Generation RNA sequencing was performed across transplanted samples as well as on human surgical samples to highlight the transcriptional similarities and differences between groups. Transcriptionally, the tHIO+S samples were more similar to human tissues than the tHIO. With these initial experiments, we concluded that the application of an intraluminal uniaxial force is a practical method to induce maturation of tHIOs in vivo without concomitant architectural disruptions. While our current system does lack certain complexities, we have demonstrated enterogenesis by means of mechanical manipulation.
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:Rearrangements involving the NUP98 gene resulting in fusions to several partner genes occur in acute myeloid leukemia and myelodysplastic syndromes. This study demonstrates that the second FG repeat domain of the NUP98 moiety of the NUP98-HOXA9 fusion protein is important for its cell immortalization and leukemogenesis activities. We demonstrate that NUP98-HOXA9 interacts with MLL via this FG repeat domain and that, in the absence of MLL, NUP98-HOXA9-induced cell immortalization and leukemogenesis are severely inhibited. Molecular analyses indicate that MLL is important for the recruitment of NUP98-HOXA9 to the HOXA locus and for NUP98-HOXA9-induced HOXA gene expression. Our data indicate that MLL is crucial for NUP98-HOXA9 leukemia initiation. Overall design: To identify the regulated genes by the NUP98 moiety of NUP98-HOXA9, we performed gene expression profiling in full-length NUP98-HOXA9- and NUP98-HOXA9 deletion mutant-expressing cells.
Project description:SEM cells were established from the peripheral blood of a 5-year-old girl in relapse with acute lymphoblastic leukaemia (ALL). SEM cells exhibit the t(4;11) chromosomal rearrangement, which leads to production of the MLL-AF4 fusion protein. Hematopoietic transcription factors including HOXA9 and MEIS1 are highly expressed in ALL. ChIP-seq was performed against HoxA9 and MEIS1 in SEM cells. DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing.
Project description:Importantly increasing evidence shows that Hox genes such as Hoxa9 are key regulators of stem cell self-renewal and hematopoiesis. Hoxa9 is expressed in early hematopoietic progenitor cells and promotes stem cell expansion. In contrast Hoxa9 down regulation is associated with hematopoietic differentiation. In addition to its role in development, HOXA9 has been intensively studied because of its central role in human acute leukemias. Despite their obvious biomedical importance, the mechanisms through which Hoxa9 and its partner proteins exert their downstream functions are poorly understood. Using whole-genome gene expression profiling, we identified direct targets of Hoxa9 in murine MHPs after 4-OHT withdraw, resulting in cell differentiation. Bone marrow cells were harvested from 5-Fluorouracil treated female 6-8 week old C57BL/6 mice and transduced with an MSCV-based retrovirus expressing Hoxa9 fused to a modified estrogen receptor ligand binding domain (Hoxa9-ER). Hoxa9-ER cells were washed 3x and resuspended in IL-3+ media with/without 100 nM 4-OHT (Sigma). At selected intervals, cells were removed for flow cytometric analysis using anti-Gr1 and anti-Mac1 antibodies (BD biosciences), morphologic assessment by cytocentrifugation and staining with Diff-Quick reagents (Intl. Med. Equip.), and RNA collection. For RNA, Pellets were lysed in Trizol reagent (Invitrogen) and RNA was extracted following manufacturer's instructions until phase separation, after which RNeasy columns (Qiagen) were employed for further purification. cRNA probes were synthesized at the University of Michigan microarray core. Probes were hybridized to Affymetrix Mouse 430 2.0 array.