Mus musculus
Ontology highlight
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PROVIDER: PRJNA243374 | ENA |
REPOSITORIES: ENA
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Project description:Despite correlations between histone methyltransferase (HMT) activity and gene regulation, direct evidence that HMT activity is responsible for gene activation is sparse. We address the role of the HMT activity for MLL1, a histone H3 lysine 4 (H3K4) methyltransferase critical for maintaining hematopoietic stem cells (HSCs). Here we show that the SET domain and thus HMT activity of MLL1 is dispensable for maintaining HSCs and for supporting leukemogenesis driven by the MLL-AF9 fusion oncoprotein. Upon Mll1 deletion, histone H4 lysine 16 (H4K16) acetylation was selectively depleted at MLL1 target genes in conjunction with reduced transcription. Surprisingly, inhibition of SIRT1 was sufficient to prevent the loss of H4K16 acetylation and the reduction in MLL1 target gene expression. Thus, recruited MOF activity, and not the intrinsic HMT activity of MLL1, is central for the maintenance of HSC target genes. In addition, this work reveals a role for SIRT1 in opposing MLL1 function. 11 Samples, 5 controls and 5 KOs with antibodies H3K4me1, H3K4me3, and H3K27Ac. One input Sample.
2014-04-03 | E-GEOD-56456 | biostudies-arrayexpress
Project description:Despite correlations between histone methyltransferase (HMT) activity and gene regulation, direct evidence that HMT activity is responsible for gene activation is sparse. We address the role of the HMT activity for MLL1, a histone H3 lysine 4 (H3K4) methyltransferase critical for maintaining hematopoietic stem cells (HSCs). Here we show that the SET domain and thus HMT activity of MLL1 is dispensable for maintaining HSCs and for supporting leukemogenesis driven by the MLL-AF9 fusion oncoprotein. Upon Mll1 deletion, histone H4 lysine 16 (H4K16) acetylation was selectively depleted at MLL1 target genes in conjunction with reduced transcription. Surprisingly, inhibition of SIRT1 was sufficient to prevent the loss of H4K16 acetylation and the reduction in MLL1 target gene expression. Thus, recruited MOF activity, and not the intrinsic HMT activity of MLL1, is central for the maintenance of HSC target genes. In addition, this work reveals a role for SIRT1 in opposing MLL1 function.
2014-04-03 | GSE56456 | GEO
Project description:The MLL1 histone methyltransferase gene undergoes many distinct chromosomal rearrangements to yield poor-prognosis leukemia. The remaining wild-type allele is most commonly, but not always, retained. To what extent the wild-type allele contributes to leukemogenesis is unclear. Here we show using rigorous, independent animal models that endogenous MLL1 is dispensable for MLL-rearranged leukemia. Potential redundancy was addressed by co-deleting the closest paralog, Mll2. Surprisingly, Mll2 deletion alone had a significant impact on survival of MLL-AF9-transformed cells and additional Mll1 loss further reduced viability and proliferation. We show that MLL1/MLL2 collaboration is not through redundancy but regulation of distinct pathways. These findings highlight the relevance of MLL2 as a drug target in MLL-rearranged leukemia and suggest its broader significance in AML. We used microarray to investigate the effect of Mll1 deletion on gene expression in LSC-enriched MLL-AF9 leukemia cells.
2017-01-20 | GSE93621 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below. Our understanding of acute leukemia pathology is heavily dependent on 11q23 chromosomal translocations involving the mixed lineage leukemia-1 (MLL1) gene, a key player in histone H3 lysine 4 (H3K4) methylation. These translocations result in distinct MLL1-fusion (MLL1F) proteins that are thought to drive leukemogenesis. However, the mechanism behind increased H3K4 trimethylation in MLL1F-leukemic stem cells (MLL1F-LSCs), following loss of catalytic SET domain of MLL1 (known for H3K4 mono- and dimethylation), remains unclear. In our investigation, we introduced a homozygous loss-of-function point mutation in MLL1 within human induced pluripotent stem cells. Remarkably, this mutation mimics the histone methylation, gene expression, and EMT phenotypes of MLL1F-LSCs- without the need for a translocation or functional wild-type MLL1. This observation underscores the essential role of MLL1's enzymatic activity in restraining the cascade of epigenetic changes associated with the gene activating H3K4 trimethylation mark, which we show is catalyzed by mislocalized SETd1a H3K4 trimethyltransferase in the absence of MLL1’s enzymatic activity. Challenging existing models, our findings imply that MLL1F-induced leukemias arise from a dominant-negative impact on MLL1's histone methyltransferase activity. We advocate for a therapeutic paradigm shift, targeting SETd1a for precision medicine. This work opens new avenues for addressing the complexities of MLL1-associated leukemias and improving targeted therapies.
2024-09-09 | GSE213239 | GEO
Project description:MLL1 translocations encode fusion proteins retaining the N-terminus of MLL1, which interacts with the tumor suppressor, menin. This interaction is essential for leukemogenesis, thus is a promising drug target. However, wild-type MLL1 plays a critical role in sustaining hematopoietic stem cells (HSCs), therefore disruption of an essential MLL1 cofactor would be expected to obliterate normal hematopoiesis. Here we show that rather than working together as a complex, menin and MLL1 regulate distinct pathways during normal hematopoiesis, particularly in HSCs and B-cells. We demonstrate the lack of genetic interaction between menin and MLL1 in steady-state or regenerative hematopoiesis and in B-cell differentiation despite the fact that MLL1 is critical for these processes. In B-cells, menin- or MLL1-regulated genes can be classified into three categories: 1) a relatively small group of co-regulated genes including previously described targets Hoxa9 and Meis1 but also Mecom and Eya1, and much larger groups of 2) exclusively menin-regulated and 3) exclusively MLL1-regulated genes. Our results highlight the large degree of independence of these two proteins and demonstrate that menin is not a requisite cofactor for MLL1 during normal hematopoiesis. Furthermore, our data support the development of menin-MLL1 disrupting drugs as safe and selective leukemia targeting agents. We performed gene expression analysis to determine the genes deregulated in B-cell progenitors upon loss of menin. Fraction B pro-B cells (defined as B220+CD43+HSA+BP-1- BM cells) were sorted from four MenF/F and four Rag1-cre;MenF/F mice of three weeks old. Total RNA was amplified once, labeled, fragmented and hybridized to Affymerix GeneChip Mouse Genome 430 2.0 array.
2013-08-05 | E-GEOD-49120 | biostudies-arrayexpress
Project description:The trithorax H3K4 histone methyltransferase (HMT) MLL1 has important roles for early embryonic development, hematopoiesis and neurogenesis through regulation of Hox and homeodomain factor expression. MLL1 has been previously implicated in activation of Myf5 expression through an interaction with Pax7. Here, we find that in vivo, MLL1 is necessary for efficient muscle regeneration, and for maintenance of muscle stem and progenitor cells. Loss of MLL1 in cultured myoblasts reveals an essential role for proliferation and expression of both Myf5 and Pax7. Loss of Myf5 is conditional on loss of Pax7 and exogenous Pax7 rescues Myf5 in the absence of MLL1 suggesting a role for MLL1 in Pax7 expression but not Pax7 activity. Importantly, Mll1 knockout results in a minor decrease to H3K4me3 at Pax7, a 40% decrease in Pax7 mRNA and an 85% decrease in Pax7 protein, suggesting a previously proposed non-HMT role for MLL1 may involve linking transcription to translation.
2019-08-16 | GSE108339 | GEO
Project description:Neuronal Kmt2a/Mll1 histone methyltransferase is essential for prefrontal synaptic plasticity and working memory
| PRJNA345538 | ENA
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
| S-EPMC8784167 | biostudies-literature
Project description:MLL1 translocations encode fusion proteins retaining the N-terminus of MLL1, which interacts with the tumor suppressor, menin. This interaction is essential for leukemogenesis, thus is a promising drug target. However, wild-type MLL1 plays a critical role in sustaining hematopoietic stem cells (HSCs), therefore disruption of an essential MLL1 cofactor would be expected to obliterate normal hematopoiesis. Here we show that rather than working together as a complex, menin and MLL1 regulate distinct pathways during normal hematopoiesis, particularly in HSCs and B-cells. We demonstrate the lack of genetic interaction between menin and MLL1 in steady-state or regenerative hematopoiesis and in B-cell differentiation despite the fact that MLL1 is critical for these processes. In B-cells, menin- or MLL1-regulated genes can be classified into three categories: 1) a relatively small group of co-regulated genes including previously described targets Hoxa9 and Meis1 but also Mecom and Eya1, and much larger groups of 2) exclusively menin-regulated and 3) exclusively MLL1-regulated genes. Our results highlight the large degree of independence of these two proteins and demonstrate that menin is not a requisite cofactor for MLL1 during normal hematopoiesis. Furthermore, our data support the development of menin-MLL1 disrupting drugs as safe and selective leukemia targeting agents. We performed gene expression analysis to determine the genes deregulated in B-cell progenitors upon loss of menin.
2013-08-05 | GSE49120 | GEO
Project description:The human Mixed Lineage Leukemia-1 (MLL1) complex orchestrates methylation of histone H3K4 to promote transcription and is the target of chromosomal translocations in a variety of leukemias. The MLL1 core complex comprises the MLL1 methyltransferase and the WRAD complex, which contains WDR5, RbBp5, Ash2L, and DPY-30. Recent studies have shed light on the structure and organization of the human MLL1-WRAD complex bound to nucleosomes but were not able to resolve portions of the Ash2L subunit or DPY30. We used an integrated approach combining cryo-electron microscopy and mass spectrometry-cross linking to obtain models of the MLL1-WRAD complex bound to nucleosomes containing monoubiquitinated histone H2B, which is reported to stimulate H3K4 methylation. We constructed a model containing the Ash2L intrinsically disordered region (IDR), SPRY insertion region, and Sdc1-DPY30 interacting region (SDI-motif), as well as the DPY30 dimer, which were not resolved in previous structures. In addition to the model of the active state, we resolved three additional states of MLL1-WRAD lacking one or more subunits that may reflect different steps in the assembly of MLL1-WRAD. Our results provide a more complete picture of MLL1-WRAD and how it assembles on nucleosomes to form an active methyltransferase complex.
2023-08-31 | PXD036406 | JPOST Repository