Project description:ETV6-RUNX1 is a fusion protein bringing together almost the entire coding sequence of RUNX1, including the DNA binding runt domain, and the N-terminus of ETV6 which is known to include transcriptional repressors including histone deacetylation 3 (HDAC3). Here we perform ChIP-seq for the active chromatin mark H3K27ac in the NALM6 B-cell acute lymphoblastic leukaemia cell line expressing ETV6-RUNX1 or mutant derivatives of ETV6-RUNX1: Delta helix-loop-helix (dHLH) is a deletion of the pointed domain; R139G is a point mutation in the runt DNA-binding domain.
Project description:PAX5 is a tumor suppressor in B-ALL, while the role of PAX5 fusion proteins in B-ALL development is largely unknown. Here we studied the function of PAX5-ETV6 and PAX5- FOXP1 in mice expressing these proteins from the Pax5 locus. Both proteins arrested Blymphopoiesis at the pro-B-to-pre-B cell transition and, contrary to their proposed dominantnegative role, did not interfere with the expression of most Pax5 target genes. Pax5-Etv6, but not Pax5-Foxp1, cooperated with loss of the Cdkna2a/b tumor suppressor in promoting B-ALL development. Regulated Pax5-Etv6 target genes identified in these B-ALLs encode proteins implicated in pre-BCR signaling and migration/adhesion, which could contribute to the proliferation, survival and tissue infiltration of leukemic B-cells. Together with similar observations made in human PAX5-ETV6+ B-ALLs, these data identified PAX5-ETV6 as a potent oncoprotein. 36 samples in total: A) 24 RNA-Seq samples in 5 cell types: pro-B (5 genotypes, 2-4 replicates) large pre-B (2 genotypes, 2 replicates each) small pre-B (1 genotype, 2 replicates) lymph node (1 genotype, 3 replicates) bone marrow (1 genotype, 2 replicates) B) 12 ChIP-Seq samples in 2 cell types: pro-B (H3K27me3, H3K9ac, H3K4me2, H3K4me3, H3K27ac, 1 replicate each; Pax5Etv6 ChIP, Prd ChIP, 2 replicates each; Pax5 ChIP 1 replicate) lymph node (1 genotype, 2 replicates).
Project description:Distal enhancers play critical roles in sustaining oncogenic gene expression programs. We obtained ATAC-Seq data and ChIP-Seq data using antibodies against the H3K27ac histone mark, transcription factors ERG and ETV6, and input chromatin from B-ALL cell lines and comparator B-cell cancer cell lines, including B-ALL with biallelic ETV6 inactivation, ETV6-RUNX1, and intact ETV6. We identify aberrant enhancer-like activation of GGAA tandem repeats as a characteristic feature of B-cell acute lymphoblastic leukemia (B-ALL) with genetic defects of the ETV6 transcriptional repressor, including ETV6-RUNX1+ and ETV6-null B-ALL. We show that GGAA repeat enhancers are direct activators of previously identified ETV6-RUNX1+ B-ALL “signature” genes, including likely oncogenic drivers. When restored to ETV6-deficient B-ALL cells, ETV6 directly binds to GGAA repeat enhancers, represses their acetylation, downregulates adjacent genes, and inhibits B-ALL growth. In ETV6-deficient B-ALL cells, we find that the ETS transcription factor ERG directly binds to GGAA microsatellite enhancers and is required for sustained activation of many repeat enhancer-activated genes. Together, our findings reveal a novel epigenetic gatekeeper function of the ETV6 tumor suppressor gene and establish microsatellite enhancers as a key mechanism underlying the unique gene expression program of ETV6-RUNX1+ B-ALL.
Project description:Distal enhancers play critical roles in sustaining oncogenic gene expression programs. We obtained ATAC-Seq data and ChIP-Seq data using antibodies against the H3K27ac histone mark, transcription factors ERG and ETV6, and input chromatin from B-ALL cell lines and comparator B-cell cancer cell lines, including B-ALL with biallelic ETV6 inactivation, ETV6-RUNX1, and intact ETV6. We identify aberrant enhancer-like activation of GGAA tandem repeats as a characteristic feature of B-cell acute lymphoblastic leukemia (B-ALL) with genetic defects of the ETV6 transcriptional repressor, including ETV6-RUNX1+ and ETV6-null B-ALL. We show that GGAA repeat enhancers are direct activators of previously identified ETV6-RUNX1+ B-ALL “signature” genes, including likely oncogenic drivers. When restored to ETV6-deficient B-ALL cells, ETV6 directly binds to GGAA repeat enhancers, represses their acetylation, downregulates adjacent genes, and inhibits B-ALL growth. In ETV6-deficient B-ALL cells, we find that the ETS transcription factor ERG directly binds to GGAA microsatellite enhancers and is required for sustained activation of many repeat enhancer-activated genes. Together, our findings reveal a novel epigenetic gatekeeper function of the ETV6 tumor suppressor gene and establish microsatellite enhancers as a key mechanism underlying the unique gene expression program of ETV6-RUNX1+ B-ALL.
Project description:This SuperSeries is composed of the SubSeries listed below. ETS Variant 6 (ETV6) encodes an essential transcriptional repressor abundantly expressed in hematopoietic stem and progenitor cells (HSPCs), where it is required for adult hematopoiesis. Heterozygous pathogenic germline ETV6 variants are associated with Thrombocytopenia 5 (T5), a poorly understood genetic condition predisposing to thrombocytopenia and hematologic malignancies. To elucidate how germline ETV6 variants impact the HSPC compartment and contribute to disease, we generated a knock-in mouse model harboring an Etv6R355X loss-of-function variant, which is equivalent to the T5-associated variant ETV6R359X. Under homeostatic conditions, all HSPC subpopulations are present in the bone marrow (BM) of Etv6R355X/+ mice; however, these animals display subtle shifts in the proportions and/or numbers of specific progenitor subtypes. To examine whether the Etv6R355X/+ mutation impacts HSPC function, we carried out serial competitive transplantation and observed that Etv6R355X/+ lineage-sca1+cKit+ (LSK) cells exhibit significantly impaired reconstitution compared to Etv6+/+ LSK cells with near complete failure to repopulate irradiated-recipients by the tertiary transplant. Mechanistic studies incorporating CUT&RUN, ATAC-Seq and Hi-C identify ETV6 binding at inflammatory gene loci, including those within the TNF signaling pathway, in Etv6+/+ HSPCs, mouse BM-progenitor-derived HPC5 cells, and human CD34+ cells. Further, single-cell RNA-Seq of BM cells isolated post-competitive transplantation reveals upregulation of inflammatory genes in Etv6R355X/+ compared to Etv6+/+ progenitors. Corroborating these findings, Etv6R355X/+ HSPCs produce significantly more TNF than Etv6+/+ cells post-transplantation. From these studies, we conclude that ETV6 is required to repress inflammatory gene expression in HSPCs under conditions of hematopoietic stress and this mechanism may be critical to sustain HSPC function.
Project description:Arrested bone marrow (BM) lymphoid cell differentiation underlies the emergence of the most common childhood cancer, acute lymphoblastic leukemia (ALL). Recurrent genetic lesions often directly involve transcription factors (TFs), such as ETV6 and RUNX1 found in the most common ALL translocation. Here, we studied differential gene expression in ETV6-RUNX1 primary ALL samples and the REH cell line using single cell RNA-seq (scRNA-seq). Submitter declares that the raw data will be deposited in EGA due to patient privacy concerns. The raw data can be accessed at https://www.ebi.ac.uk/ega/studies/EGAS00001004374
Project description:RUNX1 and ETV6-RUNX1 possess the same DNA-binding runt domain and are therefore expected to bind to canonical RUNX motifs. As the ETV6-RUNX1 fusion arises in the context of native RUNX1 expression, and since RUNX1 is retained or amplified in B-ALL, the two proteins are likely to compete for the same target sites. To assess this, we performed RUNX1 ChIP-seq in the presence of exogenous ETV6-RUNX1 (or non DNA binding ETV6-RUNX1-R139G) and the reciprocal experiment: ETV6-RUNX1 ChIP (using a V5 tag) in the presence of exogenous RUNX1 or vector control.
Project description:ETS Variant 6 (ETV6) encodes an essential transcriptional repressor abundantly expressed in hematopoietic stem and progenitor cells (HSPCs), where it is required for adult hematopoiesis. Heterozygous pathogenic germline ETV6 variants are associated with Thrombocytopenia 5 (T5), a poorly-understood genetic condition predisposing to thrombocytopenia and hematologic malignancies. To elucidate how germline ETV6 variants impact the HSPC compartment and contribute to disease, we generated a knock-in mouse harboring an Etv6R355X loss-of-function variant, which represents the mouse equivalent to the T5-associated variant ETV6R359X. All HSPC subpopulations are present in the bone marrow (BM) of Etv6R355X/+ mice under homeostatic conditions; however, these animals exhibit subtle shifts in the proportions and/or numbers of specific progenitor subtypes. To examine whether the Etv6R355X/+ mutation impacts HSPC function, we carried out serial competitive transplantation and observed that Etv6R355X/+ lineagesca1+cKit+ (LSK) cells exhibit significantly impaired reconstitution, with near complete failure to repopulate irradiated-recipients by the tertiary transplant. Mechanistic studies incorporating CUT&RUN, ATAC-Seq and Hi-C identify ETV6 binding at inflammatory gene loci, including those within the TNF pathway in Etv6+/+ HSPCs, the mouse BM-progenitor derived HPC5 cell line, and G-CSF-mobilized human CD34+ cells. Further, single-cell RNA sequencing of mouse LSK cells isolated six-weeks post-competitive transplantation reveals upregulation of inflammatory gene pathways. Corroborating these findings, we observe significantly increased production of TNF by Etv6R355X/+ versus Etv6+/+ HSPCs post-transplantation. From these studies, we conclude that ETV6 represses inflammatory response genes within HSPCs under conditions of hematopoietic stress, and that this mechanism may be critical to sustain HSPC function.
Project description:ETS Variant 6 (ETV6) encodes an essential transcriptional repressor abundantly expressed in hematopoietic stem and progenitor cells (HSPCs), where it is required for adult hematopoiesis. Heterozygous pathogenic germline ETV6 variants are associated with Thrombocytopenia 5 (T5), a poorly-understood genetic condition predisposing to thrombocytopenia and hematologic malignancies. To elucidate how germline ETV6 variants impact the HSPC compartment and contribute to disease, we generated a knock-in mouse harboring an Etv6R355X loss-of-function variant, which represents the mouse equivalent to the T5-associated variant ETV6R359X. All HSPC subpopulations are present in the bone marrow (BM) of Etv6R355X/+ mice under homeostatic conditions; however, these animals exhibit subtle shifts in the proportions and/or numbers of specific progenitor subtypes. To examine whether the Etv6R355X/+ mutation impacts HSPC function, we carried out serial competitive transplantation and observed that Etv6R355X/+ lineagesca1+cKit+ (LSK) cells exhibit significantly impaired reconstitution, with near complete failure to repopulate irradiated-recipients by the tertiary transplant. Mechanistic studies incorporating CUT&RUN, ATAC-Seq and Hi-C identify ETV6 binding at inflammatory gene loci, including those within the TNF pathway in Etv6+/+ HSPCs, the mouse BM-progenitor derived HPC5 cell line, and G-CSF-mobilized human CD34+ cells. Further, single-cell RNA sequencing of mouse LSK cells isolated six-weeks post-competitive transplantation reveals upregulation of inflammatory gene pathways. Corroborating these findings, we observe significantly increased production of TNF by Etv6R355X/+ versus Etv6+/+ HSPCs post-transplantation. From these studies, we conclude that ETV6 represses inflammatory response genes within HSPCs under conditions of hematopoietic stress, and that this mechanism may be critical to sustain HSPC function.
Project description:Evidence suggests childhood acute lymphoblastic leukemia (cALL) arises in early human development. Existing models of pre-leukemic initiation using the ETV6-RUNX1 fusion do not recapitulate human disease, highlighting the need for a developmentally relevant human model system. A human pluripotent stem cell (hPSC) model genome was engineered to express ETV6-RUNX1 from the endogenous ETV6 promoter. RNA-seq data from sorted hematopoietic progenitors identified according to surface markers.